nebosh oil and gas iog revision guide pdf

NEBOSH International Certificate Unit IOG1

International Technical Certificate in Oil and Gas Operational Safety

Revision Guide

RRC Ref. IOG1RNP.1.2

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UNIT IOG1: MANAGEMENT OF INTERNATIONAL OIL AND GAS OPERATIONAL HEALTH AND SAFETY

REVISION GUIDE Contents

LIST OF TOPICS PAGE Introduction ................................................................................................... 1 Element 1: Health, Safety and Environmental Management in Context........ 5 Element 2: Hydrocarbon Process Safety 1 ................................................. 23 Element 3: Hydrocarbon Process Safety 2 ................................................. 43 Element 4: Fire Protection and Emergency Response ............................... 75 Element 5: Logistics and Transport Operations .......................................... 93 And Finally... ............................................................................................. 108

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Unit IOG1: Management of International Oil & Gas Operational Health and Safety

Introduction This revision guide has been prepared with the examinations in mind; it is NOT intended to replace a proper course of learning.

This booklet contains an overview of the IOG1 course content and suggests tactics for maximising the marks you attain from examination questions. It is divided into Elements, as defined by the NEBOSH syllabus. Each element-section contains two main parts:

Revision Notes – a summary of the main course content for each element. This section does not include all of the detailed information you will be required to know and understand for the exam, but is intended to remind you of the key principles and ideas.

Exam-Style Questions – examples of NEBOSH-style questions alongside model answers. This section provides an insight into what your NEBOSH examiner will expect from you and some common mistakes to avoid. The model answers provided have been written as ideal answers, and not under examination conditions or time restraints, so it may not always be possible to produce such detailed answers in the actual examination. Some questions require you to use knowledge from more than one element of the course.

There is no substitute for hard work, and the more study time you can spare the better, but the secret is to use this time effectively.

Revising Effectively

Using the Syllabus

Your secret to success is the Syllabus for the NEBOSH International Technical Certificate in Oil and Gas Operational Safety. This sets out the structure of the Certificate course and the content of each element. If you do not already have a copy, you are strongly advised to buy one, keep it with you and read it every day. All NEBOSH examination questions are taken from the syllabus so as you become more familiar with it you will be less likely to be ‘thrown’ by a surprise question. Remember, however, that you will be expected to apply your knowledge to both familiar and unfamiliar situations.

As exam questions are set from the syllabus, mapping your study notes against the syllabus can be a very useful revision technique. If you have studied with RRC you will find that your study material generally follows the syllabus quite closely, but this exercise is important to help you appreciate the overall view which you need in order

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to familiarise yourself with the whole of the course material. When you are studying one specific section of course notes in isolation, it can be very easy to lose sight of how the material fits together, what practical use it is, or how one might make use of it in real life. Constant reference back to the syllabus will put each topic in perspective and help you to see how it relates to the field of oil and gas operational safety generally. It will also help you cross-reference the material with other related topics, which you may have to do in more complex examination questions.

To achieve this overview you need to know the elements that make up the course and how they relate to the RRC units. Note that each element in the NEBOSH syllabus (e.g. Unit IOG1 Element 1: Health, Safety and Environmental Management in Context) contains the following two important sections:

Learning Outcomes, which specify what you should be able to explain, appreciate, carry out, assess, etc. after having completed the element.

Content, which gives you the topics that you should be fully familiar with.

By using both these sections of the syllabus you can test whether you have the relevant skills, knowledge and understanding for each element or whether you need to look again at certain topics.

An effective revision technique is to take a pin (blunt, of course, for health and safety reasons!) and randomly stick it in any part of the syllabus. Now write down what you know about that topic. Initially this might be very little, in which case, refer back to your study notes and summarise the key issues that you need to work on. Make a note of this topic, then return to it a few weeks later and see how much more you can now remember. If you practise this regularly, you will eventually cover the entire syllabus and in the process find that you understand and retain the material much more effectively. This is ‘active revision’ – as it actively tests your memory to see what you have learnt – and it is far more effective than ‘passive revision’ where you simply read your study notes and usually switch off after 30 seconds, taking in little of the material.

You will find it easier if you make sure that you have an overall understanding of the topic first then fill in the detailed knowledge requirements later. Ask yourself searching questions on each topic such as: ‘What use is this?’, ‘How would a person working in the oil and gas industry apply this in real life?’, ‘What is the point of this topic?’, until you feel that you thoroughly understand why it is necessary know about that particular area. Once you have this level of general understanding, the details will be much easier to retain, and in some cases you may be able to derive them from your own workplace experiences.

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Your revision aim is to achieve this comprehensive overview of the syllabus. Once you have done this, you will be in a position to at least say something about each of the topic areas and tackle any question set on the syllabus content.

The Exam

This examination comprises one long question (worth 20 marks) and ten short questions (worth eight marks each). You have to answer ALL questions.

You have two hours to complete your answers. This means that you have approximately 25 minutes to answer the long question and, on average, eight minutes per short question. This should leave adequate time for you to read the questions thoroughly before you attempt to answer, and to read through your answers at the end.

NEBOSH are renowned for setting challenging questions and for marking strictly. The examiners are not trying to catch you out, but they do word their questions to ask for specific information. They also expect this information to be provided in the requested format.

The most common mistake that candidates make is to not read the questions properly. Often candidates provide excellent answers but, unfortunately, they do not answer the question given.

It is all well and good understanding the syllabus back to front, but it is of no use if you have poor examination technique. To achieve maximum marks, you will need to:

Read the question carefully.

Understand what information is being requested.

Understand the breadth of knowledge required.

Provide the information in a logical and coherent way.

Manage your time effectively – you need to allocate your time evenly throughout the exam to take into account the number of marks allocated per question.

It is important to identify the action verb within the question as this indicates the depth of knowledge required in your answer. The following meanings of the verbs have been identified by NEBOSH:

List – provide a list without explanation.

Identify – select and name.



Outline – give the most important features of (less depth than ‘explain’ or ‘describe’ but more depth than ‘list’).

Describe – give a word picture.

Explain – give a clear account of, or reasons for.

Define – provide a generally recognised or accepted definition.

State – a less demanding form of ‘define’, or where there is no generally recognised definition.

Give – provide without explanation (e.g. give an example of).

Sketch – provide a simple line drawing, using labels to identify specific features.

Examination Strategy

The examination process may seem complex but success simply depends on averaging around half marks or more for each question. Marks are awarded for setting down ideas that are relevant to the requirements of the question, and convincing the examiner that you understand what you are talking about. If you have the knowledge and understanding derived from studying the syllabus as set out above, then this should not be a problem.

Carefully reading and analysing the question so that you are clear about what is required to answer it is an important examination skill. The more you study past examination questions, the more familiar you will become with the way they tend to be phrased and the kind of answer the examiners are looking for.

Students often make the mistake of going into too much detail on specific topics and failing to address the wider issues. If you only deal with half of the relevant issues you can only achieve half of the marks. Try to give as broad an answer as you can, without stepping outside the subject matter of the question altogether. Ensure that you explain each issue in order to convince the examiner that you have the all-important understanding. Giving relevant workplace examples is a good way of doing this.

Last Minute Practice

Finally, a useful way to combine syllabus study with examination practice is to attempt to set and answer your own examination questions. By adding a question word, such as ‘explain’ or ‘describe’, in front of the syllabus topic areas you can produce a whole range of questions similar to many of those used in past papers. This is excellent examination practice because it serves as a valuable topic revision aid, whilst requiring you to set out your knowledge just as you would under examination conditions.



Element 1: Health, Safety and Environmental Management in Context Learning from Incidents

Investigating Incidents

When an incident occurs it should be recorded and investigated to understand why it happened and how to prevent a recurrence.

The incident investigation process is an important part of the health and safety management system and managers should be actively involved, including making sure that any recommendations are fully implemented and closed out.

The accident investigation is carried out:

To identify the immediate and root causes of the incident.

To identify corrective actions that will prevent a recurrence.

To record factual evidence for the future.

For legal reasons.

For claims purposes.

For staff morale, to demonstrate that the organisation does value employee safety.

For disciplinary purposes if worker behaviour has fallen short of the acceptable standard.

For data gathering to identify trends and patterns.

Types of incident include:

Near-miss.

Accident:

− Injury.

− Damage only.

Dangerous occurrence.

Ill-health.



The four steps in the accident investigation process are:

1. Gather factual information about the event.

2. Analyse that information and draw conclusions about the immediate and root causes:

− Immediate causes are the unsafe acts and unsafe conditions that gave rise to the event.

− Underlying or root causes lie behind the immediate causes; for example, failures in the management system.

3. Identify suitable corrective measures.

4. Plan the remedial actions.

The Importance of Learning from Major Incidents

Lessons can be learned from major incidents such as:

Piper Alpha 1988 – a blanking plate failure leading to a gas explosion and major oil platform fire.

Bhopal 1984 – an uncontrolled thermal runaway reaction in a storage tank leading to a large release of poison gas.

Buncefield 2005 – petrol spillage from an overfilled tank leading to a vapour cloud explosion and major fire.

Deepwater Horizon 2010 – a gas explosion and major fire destroyed an oil platform releasing large quantities of crude oil.

In each case, management, cultural and technical failures were key factors leading to the incident.

Hazards Inherent in Oil and Gas

Terminology

The following specific terms are relevant to inherent hazards in the oil and gas industry:

Flash point is the lowest temperature at which there is sufficient vapour to ignite.

Vapour density (relative to air) indicates whether a flammable vapour is likely to rise in the air or accumulate in low-lying areas.



Vapour pressure increases with temperature; a high vapour pressure means that the liquid is very volatile and more likely to produce a flammable vapour.

Flammable liquids have a flash point around ambient temperature.

Highly flammable liquids have a flash point below ambient temperature.

Extremely flammable liquids have a very low flash point and low boiling point, and therefore high volatility.

Lower flammable limit (or explosive limit) is the concentration below which a flammable mixture is too lean to burn.

Upper flammable limit (or explosive limit) is the concentration above which a flammable mixture is too rich to burn.

Between the flammable limits is the flammable (or explosive) range.

Toxic substances can produce serious, acute or chronic ill-health, or death.

Corrosive substances destroy living tissue by direct chemical attack.

Irritant substances cause inflammation, in particular of the mucous membranes.

Sensitising substances can cause an allergic response following either single acute overexposure or repeated chronic overexposures.

Carcinogenic substances can induce the growth of malignant tumours (cancer) capable of causing serious ill-health or death.



Properties and Hazards of Gases

The following gases used and created in the production and processing of oil and gas have hazardous properties:

Hydrogen and methane – highly flammable and explosive gases which form ignitable mixtures in air over a wide range of concentrations.

Liquefied petroleum gas (LPG) – highly flammable and, being denser than air, collects at low level and readily forms an explosive mixture. It is stored under great pressure and, on release, reverts to its gaseous state with rapid and considerable increase in volume.

Liquefied natural gas (LNG) – liquefied methane which easily vaporises with rapid and considerable increase in volume, forming a highly flammable gas.

Nitrogen – a non-flammable gas used to ‘inert’ flammable atmospheres. Liquefied nitrogen is used for pipe freezing and pipeline purging.

Hydrogen sulphide – a toxic flammable gas with an offensive odour of rotten eggs that forms explosive mixtures with air over a wide range of concentrations.

Oxygen – a non-flammable gas but it will encourage combustion, with combustible materials becoming more easily ignited in an oxygen-enriched atmosphere.

Properties and Hazards of Associated Products and Control Measures

The following products are used in the production and processing of oil and gas:

Anti-foaming agents – reduce problems caused by foam and dissolved or trapped air.

Anti-wetting agents – provide a waterproof barrier.

Micro-biocides – provide an anti-bacterial treatment.

Corrosion treatments – delay or prevent the formation of corrosion.

Refrigerants – substances used in a refrigeration cycle.

Water/steam – provides a good reservoir for heat energy and heat transfer but with a serious risk of scalding. Steam generated from a volume of water occupies a much greater volume and the pressure generated from this expansion has been the cause of many explosions.

Mercaptans – substances with offensive odours; easily detected by smell, but can lead to headaches and nausea when inhaled.



Drilling muds – used to reduce friction during drilling.

Sludges (drilling wastes including low specific activity (LSA) sludges) – may contain naturally-occurring radionuclides such as uranium and thorium.

Asbestos-containing materials (ACMs) – may be present in offshore installations built before 1999.

Hazards are related to the:

Physical form (powder, liquid, vapour, gas), which determines the potential route of entry into the body (inhalation, ingestion, skin absorption or penetration).

Hazard classification (toxic, harmful, irritant, corrosive, sensitising, carcinogenic).

Control measures will generally involve:

Risk assessment for use of hazardous substances.

Avoiding exposure as far as possible.

Safe storage and handling procedures.

Use of PPE and respiratory protective equipment appropriate for the nature and extent of the hazard.

Risk Management Techniques Used in the Oil and Gas Industries

Purposes and Uses of Risk Assessment Techniques

Risk assessment is “simply a careful examination of what, in your work, could cause harm to people, so that you can weigh up whether you have taken enough precautions or should do more to prevent harm”.

Hazard – something with the potential to cause harm.

Risk – the likelihood that a hazard will cause harm in combination with the severity of injury, damage or loss that might foreseeably occur.



The five steps to risk assessment are:

Because of the higher levels of risk in the oil and gas industries, qualitative and quantified risk assessment techniques are used to:

Identify and rank the risks.

Examine risk reduction measures to determine which to use.

Qualitative and Quantified Risk Assessment

Qualitative Risk Assessment uses qualitative methods to determine frequency and severity.

Semi-Quantitative Risk Assessment approximately quantifies frequency and severity within ranges.

Quantified Risk Assessment (QRA) involves full quantification.



Hazard Identification, Risk Estimation and Ranking of Risks

The main stages in assessment are:

How Risk Management Tools are Applied

In the oil and gas industries, low frequency, high impact incidents have catastrophic consequences and must be properly managed with strong health and safety leadership and robust safety management systems.

Risk management systems have the same common elements:

Plan – have a considered policy.

Do – have arrangements for putting the plan into practice.

Check – assess or monitor performance.

Act – review performance, leading to continuous improvement in the management system.



OHSAS 18001:2007 Occupational Health and Management Systems: Specification provides a recognisable management standard for certification (shown in the following diagram).

The elements of the system described in ILO-OSH-2001 Guidelines on Occupational Health and Safety Management Systems (ILO, 2001) are illustrated below.



Planning and implementation is a key stage, with controls needed for:

Minimising hazards and risks entering the organisation at the input stage.

Containing and controlling risks in the process stage.

Preventing risks from going off-site or in the products and services at the output stage.

Critical to the oil and gas process industries are:

Containment of hazardous materials.

Effects of hazardous processes and systems.

Effective maintenance (especially in harsh operating environments).

Process change procedures to ensure continuing plant integrity.

Risk control systems are needed for:

Physical resources.

Human resources.

Information.

Risk control systems are also needed to deal with the four main areas of risk:

Production.

Plant.

Procedures.

People.

Concept of “As Low as Reasonably Practicable” (ALARP)

The concept of “as low as reasonably practicable” (ALARP) covers risk at levels of some uncertainty:

Unacceptable risk – risk cannot be justified at this level.

ALARP (tolerability region):

− At the higher risk end, a benefit is desired and risk reduction is impracticable.

− At the lower risk end, the risk is tolerable if the cost to reduce it would outweigh the benefits.

Acceptable risk – the risk is negligible.



Other Risk Management Tools

Risk management techniques and tools can be applied in process safety risk identification and assessment, and models applied to aid risk control include:

HAZOP (Hazard and Operability Studies) – use guide words to identify:

− Any deviations from intended performance with significant risk.

− The actions that should be taken to reduce the risk to an acceptable level.

HAZID (Hazard Identification) – a hazard identification exercise that is intended to pick out as many hazards as possible for later risk assessment.

FMEA (Failure Modes and Effects Analysis) – a technique used to calculate:

− The possibility of failure or malfunction of individual components.

− The effect on the assembly or equipment itself.

Industry Related Process Safety Standards

Inherently safe and risk based design concepts, and engineering codes and good practice, are the foundations for onshore and offshore operational safety.

Inherently safer designs - designs where the design engineers use a variety of techniques to achieve risk reduction through design (the “design it out” principle).

Methods include:

Hazard elimination – get rid of the hazards as a first priority:

− Eliminate use of a hazardous material.

− Substitute with a less hazardous material.

− Discontinue the operation.

Consequence reduction – find a less hazardous solution to the same design objective:

− Reduce quantities of hazardous materials.

− Contain and evacuate spillages.

− Separate the operation from critical areas to reduce exposure to adjacent operations and personnel.

Likelihood reduction – reduce the probability of a hazardous event happening:

− Reduce the potential for human error through simplicity of design.

− Control ignition sources.



− Provide redundancy and alarms.

Sources of written, recognised good practice include:

(UK) HSE Guidance and Approved Codes of Practice (ACoPs).

National or local government guidance.

Standards from international or national accredited providers (BS, CEN, CENELEC, ISO, IEC, etc.).

Industry-specific or sector guidance from trade federations and professional institutions.

Concept of Hazard Realisation

The concept of hazard realisation involves a detailed examination of a major incident.

For example:

1. Loss of containment of hydrocarbons could lead to:

2. Ignition, which could lead to:

3. Fire or explosion, which could lead to:

4. Damage and injury to workers.

This scenario shows what the potential for damage and injury/loss of life could be. This potential enables us to determine priorities around which we introduce risk controls to prevent hydrocarbon releases.



Concept of Risk Control Barrier Models

The concept of risk control using barrier models can be illustrated using a bow-tie diagram. This represents all of the initiators of an incident scenario and the consequences, with barriers placed in between to prevent, control or mitigate the outcome of the event.

Based on Offshore Information Sheet No.3/2006, Guidance on Risk Assessment for Offshore Installations, HSE, 2006 (www.hse.gov.uk/offshore/sheet32006.pdf)



Use of Modelling

Estimation of essential data such as:

− Evaporation rate of flammable liquids from a spill.

− Dispersion of vapours/gases and concentrations at given points on and off-site.

− Types, effects and scale of fires and explosions, including maximum pressure and intensity of thermal radiation.

Identification of the key contributors to explosion risks to help prioritisation.

Exploration of the effectiveness of existing preventive and protective measures to justify the adequacy of existing controls.

An Organisation’s Documented Evidence

Organisations must have documented evidence that their safety systems are adequate:

Safety cases are legally required in some countries. In the UK, the Offshore Installations (Safety Case) Regulations 2005 (OSCR) require operators of all installations to prepare a safety case where their operations will be located in British waters and in UK-designated areas of the continental shelf.

Safety reports may be required in various countries and are needed in the UK to ensure safety of sites under the Control of Major Accident Hazards Regulations 1999, by demonstrating how the duties set out for operators in these Regulations will be met.

Purpose of Documented Evidence

Safety cases:

Are required to ensure that those involved in offshore activities design, construct, commission and operate their facilities in order to reduce the risks to as low as reasonably practicable (ALARP).

Demonstrate that the duty holder is capable of controlling major accident risks effectively.

Are core documents for checking that risk controls and safety management systems are in place and operate as they should.

Safety reports:

Contribute to preventing major accidents on sites having specified amounts of hazardous substances, normally onshore.



Demonstrate that measures are in place to prevent major accidents and limit consequences to people and the environment.

Systematically examine:

− Site activities.

− The potential for major accidents.

− What is being done to prevent major accidents.

Show:

− That a systematic process has been used to arrive at the risk controls.

− The depth to which they have been developed.

− That any shortcomings can be corrected.

The typical content of safety cases and safety reports will include:

Identification of major accident hazards.

Evaluation of major accident risks and measures taken (or to be taken) to control those risks.

Arrangements for audit and audit reports.

Confirmation that an adequate safety management system is in place.

Major accident prevention policies.

Identification of the safety critical elements in place to manage major accident hazards.

Details of the emergency plan.



Element 1 Exam-Style Questions

Short Questions

1. Gases are used and created in the production and processing of oil and gas. Identify the hazardous properties of: (a) Hydrogen. (2) (b) Nitrogen. (2) (c) Hydrogen sulphide. (2) (d) Oxygen. (2) 2. Outline the purpose and use of the following risk assessment techniques: (a) Qualitative. (4) (b) Quantitative. (4) 3. Organisations must have documented evidence that their safety systems are

adequate. Outline the purpose of:

(a) the safety case. (4) (b) the safety report. (4) 4. (a) Identify the hazardous of properties of LNG. (3) (b) Outline the risks associated with LNG. (5)

Long Question

1. Inherently safe and risk based design concepts are the foundations for onshore and offshore operational safety.

(a) Outline what is meant by ‘inherently safer design’. (2) (b) Identify the THREE principal concepts of inherently safer design. (3) (c) For each concept, outline, with examples, methods that could be

used to achieve each concept. (15)



Element 1 Model Answers

Short Questions

1. (a) Hydrogen: Highly flammable and explosive gas which forms ignitable mixtures in air

over a very wide range of concentrations (between 4.9% - 75%).

Lighter than air and forms explosive mixtures rapidly.

Easily ignited by low-energy sparks.

(b) Nitrogen: Gas will asphyxiate at high concentrations.

Liquefied nitrogen will cause cold burns.

(c) Hydrogen sulphide: Forms explosive mixtures with air over a wide range of concentrations

(4% - 46%).

Denser than air and will accumulate in low level areas, travel long distances to an ignition source and flash back.

Toxic, will irritate the eyes, skin and respiratory tract and can lead to respiratory paralysis. It will rapidly deaden the sense of smell, so its odour cannot be relied on to detect it.

(d) Oxygen: Oxygen enrichment can lead to fires and explosion.

Will react violently with oils and greases.

Oxygen is non-flammable, but will encourage combustion, with combustible materials becoming more easily ignited in an oxygen-enriched atmosphere.

2. (a) Qualitative risk assessment:

Specified activity.

Comprehensive identification and description of hazards to people or the environment.

The range of possible events is represented by broad categories.

Classification of the likelihood and severity.



Enables comparison and prioritisation.

(b) Quantitative risk assessment: Specified activity.

Application of methodology to produce a numerical representation.

Frequency and extent of a specified level of exposure or harm.

Specified people or the environment.

Enables comparison of the results with specified numerical criteria.

3. Safety case:

Legally required in some countries; Offshore Installations (Safety Case) Regulations 2005 (OSCR) require UK operators of all installations to prepare a safety case.

Required to ensure that those involved in offshore activities design, construct, commission and operate their facilities in order to reduce the risks to the health and safety of those working on the offshore installations or in connected activities to as low as reasonably practicable (ALARP).

Demonstrates that the duty holder is capable of controlling major accident risks effectively.

Core document for checking that risk controls and safety management systems are in place and operate as they should.

Safety report:

Contributes to preventing major accidents on sites having specified amounts of hazardous substances, normally onshore.

Demonstrates measures are in place to prevent major accidents and limit consequences to people and the environment.

Systematically examines the site activities, and the potential for major accidents and what is or is going to be done to prevent them.

Shows use of a systematic process to arrive at the risk controls, showing the depth to which you have gone to develop them. It shows you can correct any shortcomings.

4. (a) Hazardous properties of LNG: Easily liquefied and vaporised from the liquefied state. Forms a highly flammable odourless gas.



Non-toxic asphyxiant gas.

(b) Risks associated with LNG: Forms an explosive mixture with air. Vapour can be ignited some distance away from a leak and the flame will

spread back to the source. Will exclude oxygen from the atmosphere and asphyxiate at high.

Concentrations. Contact with its liquefied form will cause frostbite. Catastrophic vessel failure may result in boiling liquid expanding vapour

explosions (BLEVEs).

Long Question

1. (a) Engineers use a variety of techniques to achieve risk reduction through design.

“Design it out” principle.

(b) Hazard elimination.

Consequence reduction.

Likelihood reduction.

(c) Hazard elimination: Eliminate use of a hazardous material.

Substitute with a less hazardous material.

Discontinue the operation.

Consequence reduction: Reduce quantities of hazardous materials.

Contain spills.

Separate the operation from critical areas and reduce exposure to adjacent operations and personnel.

Likelihood reduction: Reduce the potential for human error through simplicity of design.

Control ignition sources.

Provide redundancy and alarms.



Element 2: Hydrocarbon Process Safety 1 Contractor Management

Scale of Contractor Use

Contractors are widely used for:

Construction.

Installation.

Repairs.

Maintenance.

Demolition.

Deconstruction.

Support vessels and diving services.

Work on drilling and exploration rigs.

Contractor Management, Ownership and Representation

A simple five step approach to managing contractors involves:

Step 1 – Planning

− Define the job.

− Identify the hazards.

− Assess the risks.

− Eliminate or reduce the risks.

− Specify health and safety conditions.

− Discuss with contractor (if selected).

Step 2 – Choosing a Contractor

− Decide what safety and technical competence is needed.

− Ask questions (use a questionnaire).

− Get evidence.

− Go through information about the job, the site or installation and site rules.

− Ask for a safety method statement.



− Decide whether subcontracting is acceptable and how health and safety will be ensured.

Step 3 – Contractors Working on Site

− All contractors sign in and out.

− Name a site or installation contact.

− Reinforce health and safety information and site rules.

− Check the job and allow work to begin.

Step 4 – Keeping a Check

− Assess the degree of contact needed depending on how the job is going, whether the contractor is working safely as agreed and whether any incidents or changes in personnel have occurred.

− Decide if any special arrangements are required.

Step 5 – Reviewing the Work

− Review the job and the contractor.

− Record the lessons.

Safe Handover – Understanding the Hazards

The process of changing from one shift to another can have significant problems, such as:

Lack of time.

Lack of formal shift handover meetings/failure to attend shift handover meeting.

Outgoing shift wanting to get off/incoming shift wanting to start.

Conflict between shifts.

Outgoing shift leaving work they don’t want to do.

Lack of face-to-face meetings or adequate written communication.

Poor shift record keeping/failure of outgoing shift to handover complete records.

Lack of continuity to ensure permits-to-work are handed over properly.

Lack of continuity with contractors.



Process Safety Management (PSM)

The process industry uses rapid hazard assessment methods such as the Dow Fire and Explosion Hazard Index and the Mond Fire and Explosion and Toxicity Index on chemical plants during process and plant development, and in the design of plant layout.

Process safety management controls include:

Spacing and configuration of operating plant.

Positioning and protection of control rooms and critical equipment.

Assessment of specifically occupied buildings.

Provision of temporary refuges and the critical safety systems associated with their integrity.

Management of Change Controls

Formal written procedures should be put in place to ensure all changes to process systems are assessed for their impact on safe process operation.

Documentation for evaluation of change may include:

− Original process system designs.

− Process flow diagrams.

− Cause and effect diagrams.

− List of control, alarm and trip settings.

− Process equipment specifications.

− Mechanical equipment specifications.

− Drawings detailing classification of hazardous areas.

− Line list.

Change proposal documentation should include:

− The proposed change.

− Date and reasons supporting the change, including all health, safety and welfare issues.

− Identification of persons who can authorise different types of change.

− Provision for monitoring, to ensure that procedures are not short-circuited or any elements missed out.



− Provision for communication and feedback, particularly where proposals for change are not approved.

Permit-to-Work Procedures

Role and Purpose of a Permit-to-Work System

To ensure that non-routine, hazardous work is assessed, planned, authorised and carried out in such a way as to ensure the health and safety of the workers involved, and others who may be affected.

To ensure that proper consideration is given to the risks and that they are dealt with before the task starts, throughout the duration of the ongoing work and at completion.

Permits-to-work detail and explain:

The work involved.

What isolations are required.

Hazards in the work to be carried out.

Precautions to avoid injury.

Key Features of a Permit-to-Work

Title and permit number.

Reference to other permits/isolation certificates in place.

Equipment, job location, and plant identification.

Description and nature of the work to be carried out.

Hazards identified and precautions necessary.

Protective equipment and PPE required.

Authorisation that it’s safe to work.

Date, time and duration of the permit.

Identification of workers in control of the work.

Permit acceptance – by those doing the work.

Considerations for extending the terms of the permit.

Returning to service on completion of the work.



Cancellation certifying that testing has been carried out and the plant satisfactorily recommissioned.

Types of Permits-to-Work

Hot work (welding, burning, grinding).

Live or high voltage work.

Working at height.

Working over water.

Work in confined spaces.

Special permits for work carried out under special conditions (maintenance work of a non-routine nature).

Interfaces

With adjacent plant:

− Consider all other plant and equipment on the installation.

With contractors:

− Consider contractors in exactly the same way as directly employed workers for the purposes of the permit-to-work system.

Safe Isolation, Lock-Out and Tag-Out Systems

The removal (isolation) of energy sources.

Prevention of accidental re-application of the energy source.

Provision of warnings and safeguards for those at work on isolated equipment and machinery.

Concerned with the safe isolation of:

− Electrical supplies.

− Hydraulic (oil) power.

− Pneumatic power and stored energy.

− Residual energy.

− Combustion engines.

− Natural gravitational forces weight.

− Steam or high-pressure water systems.



Safe Isolation Steps

Machinery or plant stopped by normal means.

All residual energy reserves exhausted/discharged.

All moving parts stopped in a safe position.

Electrical main isolator(s) must be turned “off”.

A padlock is to be fitted to the isolator to secure it in the off position.

Safety clamp should be fitted to the main isolator (where more than one person requires access).

Appropriate warning notice posted on normal means of stopping/starting the machine and/or mains isolator.

Key Principles of Safe Shift Handover

Safety Critical Communications

These include:

Shift handover.

Emergency communications.

Remote communication, e.g. between the control room and outside operators.

Permit-to-work procedures.

Informing contractors of hazards and risks.

Using radios and personal communicators, e.g. pagers, mobile phones.

Marking and labelling of plant for identification.

Informing about procedural changes.

Shift Handover

A shift handover is a critical time for passing on information about the status of operations.

Problems in communication occur:

During plant maintenance, when it runs across more than one shift.

In areas where safety systems may have been overridden.

During deviations from normal working, such as breakdowns.



When members of the team have been absent from work for long periods.

If handover takes place between experienced and inexperienced staff.

Shift handover should be:

High priority, and conducted face-to-face.

Two-way, with both sets of participants taking responsibility for its effectiveness.

Carried out using verbal and written communication, with emphasis given to written communication.

Based on analysis of the information needs of the incoming shift staff.

Given as much time as is necessary.

Operational issues communicated at shift handover include:

Operational status of the installation or process.

Maintenance operations:

− Carried out and completed.

− Begun but not completed.

Permits-to-work:

− Cleared.

− Still open.

Situations where safety systems have been overridden.

Deviations from normal working.

Emergencies that occurred during the shift.

Incidents or injuries following accidents during the shift.

Issues that will occur in the oncoming shift.

− Operational.

− Maintenance.

− Events (drills or exercises).



Plant Operations and Maintenance

Asset Integrity

The ability of an asset to carry out its intended function effectively and efficiently over its planned lifecycle and safeguard the health and safety of those exposed to it and the operating environment.

Asset integrity management:

− How we ensure that people, systems, processes and resources that deliver the integrity of the asset are put in place, used and remain effective over the asset’s lifecycle.

− Through Asset Integrity Management Systems (AIMS).

The lifecycle of any asset follows six stages:

Design – design the installation to achieve optimal integrity performance throughout the lifecycle, ensuring optimum technical safe solution, and that all lifecycle aspects are considered.

Construction – construct in accordance with design and, through quality planning process, confirm delivery up to and including ‘mechanical completion’.

Commissioning – demonstrate through function testing and acceptance that design specification has been achieved and that Performance Standards are being met.

Operations – operate plant within design limits and implement and monitor management systems.

Modifications – control changes to asset and/or operation.

De-commissioning – remove from service entire installation.

Asset integrity requires:

Inspection, which is required:

− After installation or re-installation – before being used for the first time or after refitting, to prevent faults from incorrect installation.

− Where deterioration leads to a significant risk – e.g. items of equipment left out in all weathers or in a harsh environment.

− Where exceptional circumstances may jeopardise safety – e.g. after major modifications or repair, known or suspected damage, change of use or after long periods of disuse.



Maintenance

Routine checks and maintenance should be carried out to ensure that all equipment operates efficiently and effectively and remains in a safe condition.

Strategies to maintain plant and machinery in a safe condition include:

− Emergency/breakdown maintenance:

− Breakdown or failure does not have safety implications or affect production.

− Opportunity maintenance:

− ‘Downtime’ is used to carry out maintenance.

− Working adjustments:

− Failures are identified and can be repaired with plant running.

− Servicing and inspection:

− Potential failures are looked for and remedial action taken before failure occurs.

− Shut-down maintenance:

− Production or process is dependent upon all equipment functioning and must all be shut down for maintenance.

− Planned preventive maintenance (PPM):

− Planned and operated to minimise lost production time.

− Routine condition-monitoring:

− Safety critical parts are monitored for early identification of potential failure.

Planned preventive maintenance (PPM) should be applied where:

− The safety of an item of equipment or machinery depends on the installation conditions.

− An item of equipment or machinery is exposed to conditions that could cause dangerous deterioration.

The programme should be based on regular inspections of the equipment or machinery and should be recorded.



Testing

Some testing procedures may be required under national or local regulations, such as:

− Pressure vessels (including pipelines) – in accordance with a written scheme of examination.

− Lifting equipment – six-monthly if persons are carried; 12 months for other, unless specified in a written scheme by the operator.

Corrosion prevention

Two main principles by which corrosion may be prevented or minimised:

− Surface coating – a metallic surface is insulated from the corrosive medium by a protective coating (paints, varnishes, and metallic films).

− Corrosion resistant materials – metals or alloys having an inherent resistance to corrosion, used where:

− Corrosive action is severe.

− Mechanical abrasion is likely to damage surface coatings.

Risk Based Maintenance and Inspection

A formal process to identify the items of plant and equipment that have a risk of degradation, breakdown or failure.

Critical items are ranked in relation to their risk.

The maintenance system aims to eliminate, reduce or manage the risks, based on an estimation of the:

− Probability of equipment, plant or component failure.

− Consequences of that failure.

Risk based inspection schemes allow a plan for carrying out critical inspections, using the following approach:

− Ensure the risks are reduced to as low as reasonably practicable (ALARP).

− Optimise the inspection schedules.

− Inspect the most critical items of plant, equipment and components.

− Use the most appropriate inspection methods.



Techniques, Principles and Importance of Safe Operation Procedures and Maintenance

Safe operation requires:

Planned activities.

Controlled timetables.

Operational guidelines.

Controlled and regulated shift patterns of skilled operatives and technicians.

Standard operation procedures are the day-to-day procedures that cover activities such as:

Start up.

Shift handover.

Shut-down.

Loading and unloading.

Planned maintenance.

Performance standards for:

− Operations.

− Plant and equipment.

− Structures.

− Pipelines.

− Handling chemicals and materials.

Emergency plans.

Permit-to-work systems.

Safe isolation procedures.

Training programmes and competence assurance.

Maintenance activities must be carefully planned in advance, following risk assessment. Key precautions include:

The use of competent maintenance workers.

Procedural measures such as permit-to-work.



Ensuring suitable means of access to the work area.

Physical isolation of the equipment.

To carry out maintenance activities safely all the risks to the maintenance worker have to be:

Identified at the planning stage.

Controlled by a range of both technical and procedural measures.

Control of Ignition Sources During Maintenance and Operations

Fire hazards in maintenance and operations include:

Hot work (welding, burning, cutting, soldering).

Use of flammable materials (solvents, gas cylinders, etc.).

Use of combustible materials (packaging, wrapping, filling materials).

Electrical work – especially on poorly maintained systems.

Use of defective portable electrical equipment, including extension leads.

Overloading an electrical system used in the work and use of socket adaptors.

Workers smoking or burning rubbish on-site.

Precautions include:

Use of hot work permits.

Regular fire safety checks in the hot work area (during and after work).

Use of burning/welding/soldering equipment only by qualified persons.

Consider fabrication of components off-site.

Portable appliance testing and maintenance of electrical systems.

Proper control of flammable and combustible materials used or stored.

Regular removal of rubbish.

Prohibiting smoking.

Cleaning and Gas Freeing

These processes are applied to tanks and vessels:

− When changing from one product to another.



− Before entry into the vessel for inspection and maintenance purposes.

In maintenance cases, the tank must be:

− Cleaned to remove residues of product and contaminants.

− Gas free.

Often steam is used for both cleaning and gas freeing.

Gas freeing can be achieved by blowing fresh air into the vessel.

Purging

Pumping an inert gas into the tank or vessel until hydrocarbons have been expelled (to below around 1%).

Makes the vessel gas free for maintenance and inspection entry purposes.

Venting

Blowing air through the vessel to expel hydrocarbons and other gases.

Offshore Draining of Water and Product

Done under process pressure to remove the contents, which are then washed out with sea water.

Achieved by the operation of collectors and drain valves in the tank and pipework systems.

Contaminants are drained into a collector tank:

− Closed drain system (to prevent the escape of flammables).

− Separator to remove the contaminants (which are collected and disposed of safely).

− Water disposed of to the drains (or into the sea offshore).

Oxygen and Non-Condensable (NCD) Gases (Hydrogen, Nitrogen and Hydrocarbon Gases)

Drained through a collector and separator system.

Treat before allowing safe discharge.

Inerting:

− Creates a safe atmosphere within a vessel in which hydrocarbon vapours cannot burn.



− Uses an inert gas:

− Nitrogen.

− Nitrogen-enriched air.

− Steam.

− Carbon dioxide.

− Increases the lower flammable limit, decreases the upper flammable limit and reduces the oxygen concentration in a vessel to a safe level.

− Used to:

− Retain a safe atmosphere within an empty tank (usually after cleaning and gas freeing).

− Form a blanket above a flammable product (usually nitrogen) to prevent the emission of vapours and make the load safer to store and carry.

Start-Up and Shut-Down

Organising, Planning and Controlling Maintenance

It is vital for the safety of maintenance personnel that:

All services are stopped, isolated, drained down, blanked, and remain in a safe condition for the duration of the work.

All liquids, gases and residues are removed, leaving the plant safe to work on.

The work is carried out under the controls of a permit-to-work.

Systems are put back into operable condition before start-up.

Water

Can cause problems if introduced or allowed to accumulate in process plant, by:

− Flashing to steam in processes operating above its boiling point.

− Reacting violently with other chemicals.

− Causing long-term corrosion damage.

Process removal and arrangements to prevent contamination are important design and operational requirements.

Hydrates

Form when there is a drop in temperature of natural gas containing water.



Accumulate as solid or semi-solid compounds (resembling ice crystals) and can impede the passage of natural gas through valves and gathering systems, causing blockages which could lead to ruptures.

Can occur in a range of oil and gas activities such as:

− Drilling operations.

− Offshore facilities, including sea-floor pipelines.

− Onshore plants such as refineries.

Need to be removed from all hydrocarbon conveying systems, often requiring shut-down and venting in order to facilitate their removal.

Testing, Commissioning and Hook-Up

Following maintenance, establish that:

All isolations have been re-made.

All blanks have been removed.

All tools and service equipment have been taken out of the area.

There may be a requirement to carry out certain tests:

Pressures, temperatures, flow rates, etc.

Ensuring safety items are fully and correctly functioning:

− Pressure relief valves.

− Diverter valves.

− Bursting discs.

Safe operation of new components.

Pipework and system components:

− Pressurised, pressure tested and leak tested.

− Functionally and operationally tested.

− Integrity testing.

− Non-destructive testing (NDT) to check the quality of welds.




Short Questions

1. The process of changing from one operational team to another can have significant problems, especially where 12-hour shifts operate.

Outline the hazards associated with shift handover. (8)

2. Outline the key features of a permit-to-work for electrical maintenance work. (8)

3. (a) Give the meaning of ‘safe isolation’. (2)

(b) Outline the stages involved in safe isolation of mechanical equipment. (6)

4. Maintenance is a key element of safe plant operation.

Identify, AND state the application of, FOUR strategies to maintain plant and machinery in a safe condition. (8)

Long Question

1. Explain the FIVE principal steps involved in effective contractor management. (20)




Short Questions

1. Not enough time allowed for shift handover.

No formal shift handover meetings held.

Off-going/on-coming members failing to attend shift handover meeting.

Outgoing shift wanting to get off.

Incoming shift seeing problems ahead and wanting to get on with them.

Conflict between the shifts (how much the off-going shift actually achieved, etc.).

A tendency for the off-going shift to leave work they don’t want to do.

Failure to meet face-to-face to discuss the issues.

Failure to use adequate written communication.

Not keeping good shift records.

Off-going shift failing to handover records, or leaving things out.

No continuation between parties to ensure permits-to-work are handed over properly.

Lack of continuity with contractors.

2. Title/permit number/reference to other permits/isolation certificates in place.

Equipment, distribution board, circuit or job location, and plant identification.

Description and nature of the electrical work to be carried out.

Hazards identified and precautions necessary.

Protective equipment and PPE required.

Authorisation that it’s safe to work.

Date, time and duration of the permit.

Identification of employees in control of the work.

Permit acceptance – by those doing the work.



Considerations for extending the terms of the permit.

Returning to service on completion of the work.

Cancellation certifying that testing has been carried out and the plant satisfactorily recommissioned.

3. (a) Safe isolation: The interruption, disconnection and separation of all the equipment’s

motive power sources.

Disconnection and separation is secure by lockable means.

(b) Machinery or plant to be worked on with power isolated stopped by normal means.

All residual energy reserves (pneumatic, hydraulic, electric, etc) exhausted/discharged.

All moving parts stopped in a safe position suitable for the work to be carried out.

Electrical main isolator(s) turned “OFF” (primary means of isolation on most plant and equipment).

Padlock fitted to the isolator to secure it in the off position (with locks labelled/coded to identify the owner).

4. Emergency/breakdown maintenance:

− Breakdown or failure does not have safety implications or affect production.

Opportunity maintenance:

− ‘Downtime’ is used to carry out maintenance.

Working adjustments:

− Failures are identified and can be repaired with plant running.

Servicing and inspection:

− Potential failures looked for and remedial action taken before failure occurs.

Shut-down maintenance:

− Production or process is dependent upon all equipment functioning and must all be shut down for maintenance.



Planned preventive maintenance (PPM):

− Planned and operated to minimise lost production time.

Routine condition-monitoring:

− Safety critical parts are monitored for early identification of potential failure.

(Only four were required.)

Long Question

1. Step 1 – planning:

− Define the job.

− Identify the hazards.

− Assess the risks.

− Eliminate or reduce the risks.

− Specify health and safety conditions.

− Discuss with contractor.

Step 2 – choosing a contractor:

− Define safety and technical competence needed.

− Use a questionnaire.

− Go through information about the job/site/installation/site rules.

− Ask for a safety method statement.

− Decide whether subcontracting is acceptable and how health and safety will be ensured.

Step 3 – contractors working on-site:

− Ensure all contractors sign in and out.

− Name a site or installation contact.

− Reinforce health and safety information and site rules.

− Check the job and allow work to begin.

Step 4 – keeping a check:

− Ensure that the contractor has full control of their work.

− Establish a plan, and meet regularly to monitor progress.



− Make sure all safe systems of work are closely followed.

− Make sure that all incidents are reported and investigated.

Step 5 – reviewing the work:

− Evaluate the standard and quality of the contractor’s work.

− Evaluate their ability to follow the plan and meet deadlines.

− Evaluate the safety of their performance throughout.

− Record the contractor’s performance and any lessons learned.



Element 3: Hydrocarbon Process Safety 2 Failure Modes

There are many ways in which vessels, pipework and equipment can suffer wear, tear and failure in the materials of their construction, including:

Creep

At elevated temperatures, and with a constant load/stress applied close to the elastic limit, a slow process of plastic deformation occurs, depending on:

− Time.

− Temperature.

A major factor in hot, high pressure environments such as furnaces and turbines.

Has been known to lead to:

− Excessive deformation in turbine blades.

− Rupture of pressure systems (fractured steam pipes).

Stress

During operation, the body of a vessel or pipe-work system may be subjected to stresses arising from:

− Periodic fluctuations in operating pressure.

− Temperature cycling.

− Vibration.

− Water hammer.

− Periodic fluctuations of external loads.

If a material is stressed beyond its yield point, varying degrees of permanent extension or distortion will occur.

If the endurance limit is exceeded, fatigue failure will occur.

Stress Corrosion Cracking

Occurs when three criteria appear together:

− A susceptible material.



− A corrosive environment.

− Enough tensile stress to induce the condition.

Is worse:

− In corrosive environments.

− At elevated temperatures.

Examples include:

− Caustic embrittlement of steel boilers.

− Stress corrosion cracking of stainless steels in the presence of chloride ions.

Thermal Shock

Makes material expand and contract, setting up cyclic stress reversal, leading to fatigue failure:

− Different parts of an object expand by different amounts, causing expansion to occur unevenly.

At some point the stress will overcome the strength of the material, causing it to crack.

− The crack may continue until the object/material fails.

Examples include brittle fractures from stress or strain across a weld in ductile material.

Brittle Fracture

Occurs suddenly and without warning, when:

− An excessive load is placed on a structure.

− The material is not able to slip due to structure or timescale.

Small cracks spread through the material quickly:

− A massive failure is produced.

− Some of the energy in the material is released as sound (characteristic “crack”).

Can also be part of the sequence in other failure modes (e.g. ductile).

Promoted by:

− Low temperature.

− Impact or “snatch” loading.



− Residual tensile stresses.

− Inherently brittle material.

In welded structures, it depends on:

− Plate thickness.

− Residual stresses present after fabrication.

− The operating temperature.

Meaning of “Safe Operating Envelope”

Defines the boundaries that contain the controlled chemical reaction process which avoids a hazardous situation occurring.

In this operating envelope, safety is determined within the designer’s boundaries (often with upper and lower limits).

Safe operation requires definition of how violations beyond the limits and system failures are to be detected and corrected.

Design constraints may allow fault tolerance and recovery, providing there are adequate warning systems to indicate system over-run or failure.

Modern process facilities rely heavily on fault detection, alarm systems and safety-instrumented systems to maintain operations within the safe operating envelope.

Use of Knowledge of Failure Modes in Initial Design, Process and Safe Operation

Designers must qualitatively evaluate stresses and safety factors for protection against failure, using data from:

− Design loads of vessels, pipe-work or equipment.

− Maximum stresses due to the design loads.

Creep can cause excessive deformation in turbine blades and the rupture of pressure systems.

Prevention should be controlled by:

− Careful design of the shape of the components.

− Choice of materials (chrome-molybdenum steels have low creep characteristics).

Thermal shock can be avoided by using materials that have:



− Sufficient strength to withstand it.

− Appropriate thermal conductivity and heat capacity for the conditions in which they will operate.

Failure of the Annular Rim

The annular rim is the name given to the bottom rim of a storage tank. It is prone to failure due to:

Rapid corrosion if the fluids stored in the tank have high sea water content.

Settlement of the tank into or onto a foundation, leading to corrosion as the joints and protective finishes are affected by the movement.

Bacterial corrosion from high sulphur content of hydrocarbon products.

The result of this corrosion and settlement is:

Mechanical failure of the rim and bottom plates.

Loss of containment.

Other Types of Failures

Weld Failures

The strength of a welded joint will depend on the type of joint and the quality of the welding.

The soundness of welds is checked by visual inspection and non-destructive testing, using the following methods/techniques:

− Visual – observing surface defects.

− Dye penetrant – uses dye to highlight the defect.

− Magnetic particle – defects distort the magnetic field and particles lie ‘differently’.

− Eddy current – discontinuities in the surface cause a variation of the eddy current.

− Ultrasonic – defects cause a variation in the return ultrasonic signal.

− Radiography – radiation passed through the material darkens the film emulsion, which shows where any defect exists.

− Pressure testing – subjects a finished pressure system to a test at some value above the working pressure.



The following table summarises non-destructive testing methods:

Test Advantages Disadvantages

Visual Quick and inexpensive. Surface defects only. Surface must be clean and accessible.

Dye penetrant

Inexpensive and convenient. Superior to visual examination alone. For all non-porous materials.

Surface defects only. Defects must be open to the surface.

Magnetic particle

More sensitive than dye penetrant. Can also find sub-surface defects.

Ferrous metals only. Cannot find defects at any significant depth. Requires a power source.

Eddy current Rapid detection of surface or sub-surface flaws. Can measure depth of shallow flaws.

Cannot operate close to other free surfaces, e.g. thin sheet. Cannot find deep flaws. Requires a power source.

Ultrasonic Precise location of internal and external defects. Sizing of many defects possible.

Expensive equipment. Dependent on a skilled operator and a power supply.

Radiography Permanent, pictorial, easily interpreted images obtained. Locates majority of internal defects.

Safety hazards (radiation). Expensive x-ray sets. Thickness limits (more so with x-rays). Power supply needed. Needs access to both sides.

Pressure testing

System can be tested while in operation.

Cleaning problem if hydraulic medium used in a gaseous system.



Safety Critical Equipment Controls

Safety Control

Safety critical equipment includes:

Process equipment controls.

Fire and gas controls.

Emergency shut-down.

Drilling systems.

Emergency Shut-Down Equipment and Systems

Intended to monitor and detect faults in processes and service systems.

When faults are detected they will shut down to:

− Prevent escalation of a hazardous event.

− Protect people and property on the installation from damage.

Safety Integrity Levels for Instrumentation

Every instrumented protective function should have its safety criticality established:

− Usually indicated by using safety integrity levels (SILs).

There are generally four levels, each corresponding to a range of “likelihood of failure” targets:

− SIL 1 will be at the highest Probability of Failure on Demand (PFD).

− SIL 4 will be at the lowest PFD.

The higher the safety integrity level, the more critical the safety function (e.g. trip systems, fire and gas, HIPS, relief and blowdown systems).

All safety critical instrumented protective functions need regular tests to prove that their performance standards continue to be met:

− All test results should be recorded.

− The higher the integrity of the system, the more stringent the testing required will be.



Procedures for Bypassing ESD

Emergency shut-down systems should not generally have bypass (inhibiting or override) facilities, unless they are very closely controlled and only operated under permit conditions.

Where bypass systems are provided, they should be:

Generated and authorised by a competent person with suitable justification.

Risk assessed to determine the safe conditions and controls required.

Applied for the shortest possible periods of time.

Monitored and controlled for any continued application.

Tested to ensure they function correctly.

Fully tested after reversal to ensure ESDs function correctly when reinstated.

Entered in a bypass log when operated.

Controlled in number to prevent deterioration of safe operations and enable effective management.

Blowdown Facilities and Flare Types

Blowdown

The removal of liquid content from process vessels and equipment to reduce the likelihood of fires or explosions occurring.

Gas flares

Gas combustion device used to eliminate waste gas not required in other processes or for transportation.

Act as a safety system for non-waste gases released by pressure relief valves during unplanned over-pressuring of plant equipment.

In emergency situations the flare can burn-out total reserve gas.

Drains, Sewers and Interceptors

On offshore installations drains usually consist of a series of:

− Non-hazardous open drains:

− Open to the atmosphere.

− Include drainage from:



− Normal ground waters (rainwater and wash-down from hoses, etc.).

− Areas with hazardous safety ratings (water which may contain oil, etc.).

− Hazardous closed drainage systems:

− Connected directly to pressure vessels.

Sewage can be collected through a sewer system and put through a treatment plant.

Interceptors:

− Used at onshore installations to collect and separate ground waters that fall and are drained from hazardous areas, or process waters that are discharged. These consist of settling bays which allow water to flow through while oil is collected, sucked out and disposed of.

− Offshore, interceptors are referred to as oil/water separators. These separate oil from water before it is discharged into the sea.

Safe Storage of Hydrocarbons

Hazards and Risks

Risks associated with the storage of hydrocarbons include:

Over-filling of storage vessels due to:

− Failure of the operator to monitor filling (when filling manually).

− Failure of the pumping system to shut off.

− Lack of or failure of over-filling sensors and alarms.

− Blockage or lack of adequate tank venting or relief systems.

The effects of vacuum, such as collapse or distortion.

Failure of tank shells and associated pipework due to:

− Natural forces and pressures exerted by the wind or earthquakes.

− Corrosion reducing the thickness of tanks.

− Poor installation and deformation of the settlement of foundations and tank bases.

− Faulty welding or the use of sub-standard steels in manufacture.

− Inadequate shell thickness for the pressure or vacuum conditions.



Floating Roof Tanks

Can move up and down within the outer shell of the tank.

Always remain immediately above the surface of the liquid contained.

Minimise the air gap and potential build-up of flammable hydrocarbon vapours.

There are two main types of floating roof tank:

− External floating roof tank:

− Used to store medium flashpoint hydrocarbons.

− Has a rim seal in place between the main shell of the tank and the floating roof to cut down on vapour evaporation and escape through the floating roof.

− A major disadvantage is lightning, which can cause ignition at the rim around the roof seal, causing major tank fires.



External floating roof tank



− Internal floating roof tank

− Used for storing lower flashpoint hydrocarbons.

− Has a fixed roof in place over the floating roof.

− Design reduces the likelihood of lightning strikes igniting vapours at the rim seal of the floating roof, cutting down the potential for tank fires.

Internal floating roof tank



Fixed Roof Storage Tanks

Intended for use with liquids that have very high flash points.

Constructed of steel or other material suitable to withstand the effects of direct flames or radiant heat from a fire in the vicinity.

Consideration should be given to the chemical and physical properties of the contents to ensure they are compatible and will not cause or lead to failure of the tank.

Bunding of Storage Tanks

Tanks should be surrounded by a bund:

To limit the spread of spillage or leakage.

May contain more than one tank.

Designed to hold at least 110% of the capacity of the largest tank within the bund.

Impervious to the liquid being stored.

Designed to withstand the full hydrostatic head.

If tanks are not effectively bunded then stored materials can:

Soak into the ground, where they can pollute groundwater or contaminate land.

Enter open drains or loose-fitting manhole covers.

Contaminate springs, wells or boreholes.

Contaminate watercourses, lakes and coastal waters.



Vertical storage tank with bund

Filling of Tanks

The most common methods are:

‘Top’ filling

− Achieved by means of a filling valve arrangement (usually gravity-fed) through the top of the tank.

− More often used with smaller tanks and containers.

− Can create ‘splash’, which can:

− Contaminate the surrounding area.

− Aerate the substance and create a large electrostatic charge.

− Allow the escape of vapours.

‘Bottom’ filling

− The substance is delivered into the tank under pressure through a closed pipeline.

− The common method for larger tanks and road tankers.



− Alleviates the problem of vapour escape.

− The pressure under which the substance is delivered can cause problems unless:

− The container is designed to be pressurised.

− Pressure venting and relief devices are functioning properly.

Regardless of filling method, care must be taken to avoid over-filling, which has the potential consequences of:

Uncontrolled contamination of the environment.

Release of vapours.

Vapour-cloud formation, fire and explosion.

Pressurised and Refrigerated Vessels

Liquefied natural gas (LNG)

Liquefied close to the production facilities.

Transported in specially designed cryogenic (low temperature) sea vessels or road tankers.

Storage and delivery to a pipeline system at an LNG regasification terminal.

Liquefied petroleum gas (LPG)

Liquefied by moderately increasing the pressure or by reducing the temperature.

Refrigerated storage can be used by gas suppliers to store large volumes of LPG.

Main form of LPG storage is in special tanks known as ‘pressure tanks’:

− Vessels have very thick wall sections.

− Designed to withstand immense pressures exerted by the gas inside.

− Cylindrical or spherical in shape.

− Fire-resistance rating.



Spherical vessel for storing LPG gas

Loss of Containment and Consequences

Pool fire:

− Occurs when a flammable liquid leaks from a vessel or pipeline to form a fluid reservoir, which then ignites.

− Smoke generation depends on the fuel:

− Heavy hydrocarbons burn ‘messily’, producing large amounts of smoke.

− LNG burns cleanly, with little smoke.

Jet fire:

− Can occur following the rupture of a pressurised vessel and/or gas line.

− Properties of the fire will depend on:

− Composition of the fuel.

− Conditions under which it is released.

− Rate at which it is released.

− Direction(s) of its release.

− Weather, in particular wind conditions at the time of release.

Hydrocarbon vapour clouds:

− Arise from release of hydrocarbon fuels.



− Principles and effects of vapour cloud explosions are:

− Vapour concentration, confined within a tank, vessel (or building) increases until it is above the Lower Explosive Limit (LEL).

− Unconfined as a release of large quantities into the open air:

− A vapour cloud at a concentration within the explosive limits may travel some distance.

− Dispersal may reduce the concentration below the LEL.

− Vapour cloud explosions may arise from vaporisation of a release of liquefied gas from a ruptured vessel or pipeline.

− Explosions may be ignited by an ignition source of greater energy than the minimum ignition energy for the vapour cloud.

− Effects may be overpressure, fire, explosion and resulting debris as airborne missiles.

Boiling Liquid Expanding Vapour Explosions (BLEVE)

Result from a sudden release of vapour, containing liquid droplets, due to the rupture or overpressure of a storage vessel containing a substance that is above its atmospheric boiling point, such as propane.

Following release:

− The vapour above the liquid rapidly escapes, lowering the pressure inside the vessel.

− Loss of pressure causes the liquid to boil violently, giving off further large amounts of escaping vapour.

− Escaping vapour generates a wave of overpressure – an explosion – which can destroy the storage vessel and send debris over a large area.

Confined Vapour Cloud Explosions (CVCE)

Occur when a flammable vapour cloud ignites in a closed space (such as a process vessel or a building).

Pressure builds up until the containing walls rupture.

A relatively small amount of flammable material can lead to a significant explosion and cause considerable damage.

Have insufficient energy to produce more than localised effects.



For personnel close to the blast, missiles and flash-burns can result in serious or fatal injuries.

Unconfined Vapour Cloud Explosions (UVCE)

Result from the release of a considerable quantity of flammable gas or vapour into the atmosphere and its subsequent ignition.

The vapour cloud will begin to disperse but if it is ignited before it is diluted below its lower flammable limit, an unconfined vapour cloud explosion will occur.

Shock waves and thermal radiation will result from the explosion and can have effects both on- and off-site, causing extensive damage.

Effects are most pronounced when explosions involve reactive gases such as ethylene.

Precautions to Prevent VCEs

Location:

− Site hydrocarbon plants away from residential areas to minimise the consequences if an explosion occurs.

Storage quantities:

− Keep to a minimum, especially for volatile liquids under pressure and gases.

Design and layout:

− Include remote isolation and shut-off valves.

− As much space around and between containment vessels as possible.

− Route pipelines, cables and services together where possible.

Buildings:

− Well-ventilated and resistant to the entry of vapours.

− Minimum number of occupied buildings near plant/containment vessels.

− Consider blast protection.

Emergency and safety measures:

− Leakage monitoring devices.

− Sprinkler water supplies.

− Automated alarm systems.



Pipelines

Practical and economical for transporting oil, hydrocarbon products and gas.

Can be overland or beneath the sea.

Built from tubes of steel or plastic.

Generally buried at a depth of around 1-2 m.

Products flow by being pumped by intermediate pumping stations along the pipeline at speeds of between 1-6 m/s.

Need to be inspected and cleaned to remove build-ups.

Need a method of ensuring safety of the pipeline to protect:

− The asset (illegal tapping).

− The local population (leaks).

To counter theft and to ensure continuity of the pipeline and supply of product, detection systems are fitted in the pipelines that can detect changes in flow rates and location.

Decommissioning of Plant

Usually occurs at the end of plant life, when plant is either no longer required or is to be moved and recommissioned at another location.

The three stages are:

1. Decontamination to:

− Remove contaminants and reduce occupational health risks from exposure to those decommissioning the plant.

− Salvage the equipment and maintain its usability as far as possible.

− Clean up and restore the site environmentally.

2. Dismantling to:

− Break the equipment down further into component parts for packaging and transportation.

3. Disposal:

− Where plant and equipment is not required or not deemed fit for re-location or re-use.



− Including disposal of any contaminants that have been collected during the decontamination process.

Significant Factors for Offshore Decommissioning

Health and safety.

Environmental impact.

Technical feasibility.

Cost-effectiveness.

Management of Simultaneous Operations

Simultaneous Operations (SIMOP)

Where there is a potential clash of activities that have safety and operational implications.

Can occur due to:

− Contractor activities in the same location at the same time.

− Process failure responses, such as after hydrocarbon releases, fire or explosion.

− Interference between platform and vessel operations.

− Maintenance clashes on the same plant or area at the same time by different teams.

− Weather or environmental impacts.

Where SIMOPs are identified, those who will be involved should initially meet to draw up a plan of operation, taking into account all separate activities and their impact on other work.

Fire Hazards, Risks and Controls

Lightning

A major static electrical discharge.

Installations and plant should be protected by suitable lightning-rod applications:

− Fixed to the highest point on various items of plant and structures.

− Connected to ground to dissipate energy from a strike.

The Fire Triangle and Potential Consequences

To start a fire, the following three things are needed:



− Combustible/flammable substance or fuel (wood, paper, plastics, gas, petrol, etc.).

− Oxygen in a gas state (usually from air).

− An ignition source (or heat).

These three factors form the basis of the fire triangle.

All must be present to produce and sustain a fire.

Take any one of the three elements away, and a fire will go out.

The Triangle of Combustion (Fire Triangle)

Classification of Fires

Fires are commonly classified into five categories according to the fuel type.

The classification is useful as the basis for identifying which extinguisher to use and the classification system used in Europe is shown below:



European Standard - Classification of Fires

Stages of Combustion

Combustion can be divided into five stages:

Induction.

Ignition.

Growth.

Steady state.

Decay.



Stages of Combustion

Electrostatic Charges

The flow of flammable liquids inside a pipe can build up static electricity.

The rate of generation is determined by:

− Conductivity.

− Turbulence.

− Surface area.

− Flow rate.

− Presence of impurities.

The rate of generation and accumulation can be reduced by:

− Control of pumping rates.

− Proper pipe sizing to keep liquid velocities low.

− Elimination of splash filling and free-fall of flammable liquids by:

− Lowering fill velocities.

− Directing the discharge of liquid down the side of the vessel.

− Submerging fill pipes below the liquid level in the vessel.

− Installing filters far enough upstream of discharge points to allow adequate time for any static generated to leak away.

The biggest risk of static electrical discharge is where fuel is being transferred from one vessel to another.



Identifying Ignition Sources

Ignition sources include:

Open flames.

Electrical sparking sources.

Spontaneous ignition.

Sparks from grinding or tools.

Sparks or heat from internal combustion engines.

Static electricity.

Friction.

Hot surfaces.

Sparks.

Lasers and other intense radiant heat sources.

Chemical reactions giving rise to heat/flame.

Smoking.

Zoning and Hazard Area Classification

Hazardous area zoning classifies areas on the basis of the frequency and duration of the occurrence of an explosive atmosphere.

Zones are shown below for gas/vapours (those for dust are in brackets).

Zone 0

A place in which an explosive atmosphere consisting of a mixture of air with dangerous substances in the form of gas, vapour or mist is present continuously, or for long periods of time, or frequently (Zone 20 for dust).

Zone 1

A place in which an explosive atmosphere consisting of a mixture of air with dangerous substances in the form of gas, vapour or mist is likely to occur in normal operation occasionally (Zone 21 for dust).

Zone 2

A place in which an explosive atmosphere consisting of a mixture of air with dangerous substances in the form of gas, vapour or mist is not likely to occur in



normal operation but, if it does occur, will persist for a short period only (Zone 22 for dust).

The zone will define the requirements for the selection of equipment to be used in the hazardous area:

Zone 0 or Zone 20 – Category 1 equipment

Zone 1 or Zone 21 – Category 1 or 2 equipment

Zone 2 or Zone 22 – Category 1, 2 or 3 equipment

Types of Equipment

Intrinsically Safe Equipment (Type ‘I’)

− Has restricted electrical energy.

− Energy levels are insufficient to produce an incendiary spark.

− Can be used in Zone 0 areas.

− Faults may raise energy levels.

Flameproof Equipment (Type ‘D’)

− Allows an explosive mixture to enter the enclosure but the enclosure will withstand the pressure and heat of explosion and the ignition of the surrounding flammable atmosphere is prevented.

− Is not suitable for some combustible powders and dusts.

− Can be used in Zones 1 and 2.

− Requires regular maintenance to ensure continuing integrity.

Type ‘e’ Equipment

− Does not arc, spark or generate temperatures high enough to ignite a flammable atmosphere.

− May be used in Zone 2 areas.

Type ‘N’ Equipment (Non-Sparking)

− Intended for use in Zone 2 applications.



Furnace and Boiler Operations

Use of Furnace and Boiler Operations

Used to heat water to produce steam, which is used in the oil and gas process industries for:

− Heating.

− Steam generation for turbine operation.

− Steam washing and cleaning.

− Product recovery at wells.

− Source of heat in oil and gas processing.

Two common types:

− Closed systems – unused condensed steam goes back through the system to be re-heated.

− Open systems – where the boiler vents unused steam from the system.

Closed and open boilers are also in two forms:

− Firetube boilers – heated gases pass through the core of the firetube and heat water in the internal water tubes, which creates the steam.

− Watertube boilers – water enters the vertical tube and is heated until it becomes steam, which then passes out through the top of the tube.

At the oil refinery, crude oil is heated directly in a furnace and fractional distillation separates (by boiling point) the various petroleum products.

Hazards and Risks of Boiler Operations

Loss of pilot supply:

− Gas powering the pilot will continue to enter the unit, causing a potential build-up of flammable/explosive gases, which can lead to boiler explosion.

Over-firing and flame impingement:

− A flame that is used to heat the water in a boiler touches boiler surfaces, such as directly on heating coils or pipework. This can cause erosion and corrosion, cracking and failure of the materials.

Low tube flow:

− If tube flow reduces, heat exchange will become inefficient, causing temperature and pressure rises, which could lead to explosion.



Increase in tube-metal temperature:

− Excessive stresses are placed on boiler tubes during increased cycle demands.

Leak or release In the refining process:

− Potential for fire and explosion when crude oil is heated in a direct-fired furnace and fed into a distillation column.




Short Questions

1. Outline TWO types of failure mode that may lead to loss of containment from hydrocarbons. (8)

2. Outline the purpose and function of gas flares used in hydrocarbon processing. (8)

3. Fixed roof and floating roof are two types of storage tank.

Outline how the design of each contributes to the safe containment of hydrocarbon liquids. (8)

4. Outline the main hazards associated with operating boilers and furnaces. (8)

Long Question

1. The zones specified by hazardous area classification define the requirements for the selection of equipment to be used in that hazardous area.

(a) Outline the zone classification for flammable gases and vapours. (6)

(b) Outline, with examples, the various types of ignition protected electrical equipment AND the zones that each type could be used in. (14)




Short Questions

1. Creep

At elevated temperature, and with a constant load/stress applied close to the elastic limit, material continues to deform slowly over time.

Extent of creep depends on time and temperature.

A major factor in hot, high pressure environments such as furnaces and turbines.

Failure will occur as brittle or ductile depending upon the parent material.

Stress corrosion cracking:

Occurs with a susceptible material in a corrosive environment.

Tensile stress will induce the condition.

Is worse in corrosive environments and at elevated temperatures.

More common in alloys than pure metals and where there is exposure to chemicals.

Thermal shock:

Rapid and extreme temperature changes (hot to cold and vice versa).

Sets up cyclic stress reversal.

Different parts of an object expand by different amounts, causing expansion to occur unevenly.

Leads to fatigue failure.

Brittle fracture:

Occurs suddenly and without warning.

An excessive load is placed on a structure and the material is not able to slip.

Brittle structure of the material itself or intense load over very short time period.

Small cracks spread through the material quickly and a massive failure is produced.

(Only two were required.)



2. Gas combustion device:

Used in refineries, natural gas processing plants, oil or gas production sites (oil wells, offshore oil and gas rigs).

Used to eliminate waste gas not required in other processes or for transportation.

Acts as a safety system for non-waste gases.

Released by pressure relief valves during unplanned over-pressuring of plant equipment.

Process gases are vented through pressure relief systems and burned off.

In emergency situations the flare can burn-out total reserve gas.

Air supply is needed for complete combustion and reduction of smoke.

3. External floating roof tank:

− Open-topped cylindrical steel shell, with a roof inside the shell.

− Floats on the surface of the liquid in the tank, and will rise and fall with the liquid as its level changes.

− Minimises the air gap and potential build-up of flammable hydrocarbon vapours.

− Used to store medium flash point hydrocarbon products in large quantities.

Internal floating roof tank:

− An internal floating roof beneath a standard fixed roof.

− Minimises the air gap and potential build-up of flammable hydrocarbon vapours.

− Overcomes weather-related problems of external floating roof tanks.

− Used for storing the lower flash point hydrocarbons.

Fixed roof storage tanks:

− Constructed of steel or other material suitable to withstand the effects of direct flames or radiant heat from a fire in the vicinity.

− Designed and constructed in accordance with the appropriate recognised standards and good engineering practice.

− Intended for use with liquids that have very high flash points.



4. Loss of pilot supply:

− Gas powering the pilot will continue to enter the unit, causing a potential build-up of flammable/explosive gases, which can lead to boiler explosion.

Over-firing and flame impingement:

− A flame that is used to heat the water in a boiler touches boiler surfaces, such as directly on heating coils or pipework. This can cause erosion and corrosion, cracking and failure of the materials.

Low tube flow:

− If tube flow reduces, heat exchange will become inefficient, causing temperature and pressure rises, which could lead to explosion.

Increase in tube-metal temperature:

− Excessive stresses are placed on boiler tubes during increased cycle demands.

Long Question

1. (a) Zone 0 – a place in which an explosive atmosphere consisting of a mixture of air with dangerous substances in the form of gas, vapour or mist is present continuously, or for long periods of time, or frequently.

Zone 1 – a place in which an explosive atmosphere consisting of a mixture of air with dangerous substances in the form of gas, vapour or mist is likely to occur in normal operation occasionally.

Zone 2 – a place in which an explosive atmosphere consisting of a mixture of air with dangerous substances in the form of gas, vapour or mist is not likely to occur in normal operation but, if it does occur, will persist for a short period only.

(b) Intrinsically safe equipment (type ‘i’):

− This design ensures that the energy level is insufficient to produce an incendiary spark.

− Only ‘ia’ equipment can be used (exceptionally) in Zone 0 if sparking contacts are not part of the equipment.

− Examples of type ‘i’ equipment are instrumentation and low energy equipment.



Flameproof equipment (type ‘d’):

− Flameproof equipment is totally enclosed and the casing has to be robust enough to withstand internal explosions without igniting the flammable atmosphere in which the equipment is located.

− Examples of type ‘d’ equipment are motors, lighting, switchgear and portable handlamps.

− It is suitable for use in Zones 1 or 2 but is unsuitable for Zone 0.

Type ‘e’ equipment:

− This equipment does not arc, spark or generate temperatures high enough to ignite a flammable atmosphere.

− Examples of type ‘e’ equipment are induction motors and transformers.

− Type ‘e’ equipment may be used in Zone 2 areas.

Type ‘N’ equipment (non-sparking):

− Less stringent requirements have to be met by this category as compared with type ‘e’ equipment.

− It is intended for use in Zone 2 applications.

− Examples of type ‘n’ or ‘N’ equipment are some solid-state relays.



Element 4: Fire Protection and Emergency Response Fire and Explosion in the Oil and Gas Industries

Leak and Detection Systems

Comprised of detectors for:

− Gas/vapour

− Flame

− Heat

− Smoke

These detectors:

− Continuously monitor the area.

− Also raise the alarm on detection.

− May then initiate control action, such as emergency shut-down.

General considerations for these systems include:

Adequate number of detectors.

Suitable location:

− Considering local air flows and the density of the gas.

Maintenance/testing:

− Fault detection circuit should be incorporated.

Uninterruptible power supply:

− In the event of power failure, the protection is maintained.

Manual backup:

− Supplemented with manual call points.

Minimisation of false alarms:

− If the detector initiates some control action (such as a shut-down), a voting system can be incorporated to reduce the potential for false alarms (i.e. several detectors are required to activate to set off the alarm and subsequent control action).



Zoning:

− Detectors wired together into groups/zones so that they trigger a zone alarm on the fire alarm panel.

Leak Detection

Gas/vapour/oil mist detectors are used to detect leaks:

− From pump seals.

− In bunds.

− Pressurised hydrocarbon liquids from pin holes.

Fire Detection

Broadly divided into:

Smoke Detectors

− Ionisation types use a radioactive compound to ionise the air in a chamber, generating a small current, which is reduced when smoke particles enter the device; this triggers the alarm.

− Optical types scatter or obscure light when activated by smoke; the change is detected by a photoelectric cell, which triggers the alarm.

Heat Detectors

− Contain fusible links which melt in the fire, triggering the alarm.

− Detect expansion of either metal, liquid or air.

− Can be made to activate at:

− A fixed temperature.

− A determined rate of rise of temperature.

− Can be configured as:

− Spot (or point) type – individual units.

− Line type – cables detect temperature variations at any point along their length.

Flame Detectors (UV/Visible/IR)

− Detect either UV, visible or IR radiation emitted from the fire.

− Can be obscured by equipment and stored materials.



Passive Fire Protection

Passive fire protection (PFP) protects the structure to which it is applied, stopping (or reducing) the heat and smoke from destroying its structural integrity and limiting spread to other parts.

It is typically used:

On fire barriers:

− Structures such as walls that are designed to stop fire transmission between different protected areas/compartments.

To protect load-bearing structures:

− Columns supporting key areas such as accommodation blocks.

To protect critical equipment or components.

PFP needs to maintain three things:

Integrity – should not allow smoke or flames through.

Stability – preserving the structural strength of what it is protecting.

Insulation – preventing significant heat transmission.

PFP can come in many forms:

Preformed:

− Boards, panels, cladding, wall linings, pipe shells.

Prefabricated:

− A fire-resisting structure that has been prefabricated off-site for on-site erection.

Spray coating:

− Used on columns, beams, bulkheads, fire walls, flare booms and vessel supports.

Enclosures:

− Fire-resisting boxes or trunking placed around critical components.

Seals/sealants:

− Intumescent door seals to prevent the passage of fire and smoke and activated by heat.



Flexible jackets:

− Wrap around equipment, supports, lining bulkheads (often based on woven glass fibre) and can easily be removed for maintenance.

Active Fire Protection

Active fire protection is activated on detection of a fire to extinguish it or mitigate its effects.

Systems can be:

Fixed installations:

− Sprinkler or deluge systems.

Portable:

− Extinguishers.

Commonly, activation of fixed installations is automatic (linked to a detector) with a manual backup (e.g. opening of a valve or manual activation of a linked alarm call point).

Water-Based and Foam-Based Fire Protection Systems

A typical water-based fixed installation comprises:

Fire-water source:

− Sea water or a large water storage tank.

Fire-water pump:

− Must deliver to the required pressure and flow rate.

Fire-water mains.

Pipes transporting the water from the pump to where it is needed:

− Dry (empty).

− Wet (continuously charged with water).

Discharge point:

− Nozzles, sprinkler heads, monitors, hoses.

The common types of water-based and foam-based AFPs are:

Sprinkler systems.



Deluge systems.

Water-mist systems.

Monitors.

Hoses.

In addition to water-based and foam-based AFPs:

Dry chemical-based fire protection systems.

Gaseous inerting extinguishing systems.

Specific Examples of Fire Protection Systems

Fixed Roof Tanks

− Foam injection – overhead or sub-surface.

− Remotely activated foam monitors.

− Water deluge cooling sprays.

Floating Roof Tanks

− Fixed foam installations.

− Monitors and water deluge cooling sprays.

Process Modules

− Gas leak detection equipment.

− Overhead foam deluge.

− Foam monitors.

− Hydrants/hoses.

Spheres

− Situate the vessel underground.

− Gas leak detectors.

− Passive fire protection.

− Water deluge systems and monitors.



Gas Turbines and Compressors

− Fire-resisting enclosures (fire barriers).

− Gas detectors.

− Fixed installations using carbon dioxide or water-mist.

Refinery Process Units and Storage Terminals

− Water sprinkler and spray systems.

− Foam pourers.

− Fixed water jets.

− Inert gases for flooding enclosed spaces.

− Passive fire protection to protect against vessel failure.

− Fire walls.

Emergency Response

Emergency Response Plan (ERP)

Communicates to all parties:

− What action to take.

− Who will take that action.

− The resources needed for all likely emergencies/clean-up operations.

Signifies that emergencies have been thought through before they happen:

− When they do occur, there is understanding of what is going on and what to do.

− Prompt action prevents an incident from becoming a catastrophe.

Provides documentary evidence of preparedness to regulators:

− Especially in the case of an investigation.

Content of ERPs

Specific foreseeable emergency situations (or types):

− Their likely scale and consequences.

Organisational roles, authority, responsibilities and expertise:

− Emergency response team.

− Incident command structure.



Emergency response actions/procedures:

− From detection and raising the alarm, to the point at which the emergency has been controlled and all personnel are in a ‘place of safety’.

Provision of sufficient resources:

− People (shift work coverage, equipment, materials) and specialised emergency response equipment needed in an emergency control centre.

Evacuation procedures:

− The need to establish and maintain evacuation routes and provide for evacuation to a safe place away from the installation.

Communications:

− Between emergency responders (e.g. by radio), internal and external (regulatory) incident reporting, calling external help (escalation) and dealing with the media.

Training for personnel and drills to test the plan:

− Training to maintain readiness of the response team and other workers and liaising with external agencies such as hospitals, the coastguard and regulators.

Fire and Explosion Strategy (FES)

Output of a process which evaluates:

− Fire and explosion scenarios.

− Mitigation measures needed.

A record of a specific fire and explosion risk assessment.

Detail depends on complexity:

− Complex cases:

− Computer-based dispersion modelling.

− Simple cases:

− Industry standard codes of practice.

Evaluations would involve:

− The foreseeable fires/explosions.

− Their likelihood of occurrence and likely severity, which may depend on:

− Location.



− Nature of the gas/liquid.

− Temperature/pressure.

− Amounts in use.

− Complexity of the installation.

− Other related issues, such as:

− Human factors (i.e. how people behave in a fire/explosion).

− Remoteness of the installation (proximity of external help).

Evaluation:

− Allows selection of the most appropriate fire/explosion prevention and mitigation measures, depending on the risk.

− Feeds into the operational and procedural requirements in the ERP.

Alarms

May be activated:

− Automatically.

− Manually.

May be incorporated into fixed fire-water installations (driven by the water flow).

Initiated by fire and gas detection systems along with some control action, such as:

− Emergency shut-down.

− Activation of fire suppression.

Give an audible or visual warning to personnel.

May be varied to indicate different responses to different types of emergencies.

Medical Emergency Planning

Consider matters such as the:

Range of likely medical emergencies.

Personnel:

− Trained and adequate number.

Equipment needed for treatment and evacuation:

− Remoteness of the site and harshness of the environment.



Need to transport/evacuate the sick/injured to off-site medical facilities.

− On-site emergency response usually adopts a tiered approach:

− Level 1 – basic first-aid.

− Level 2 – advanced first-aid.

− Level 3 – utilising medics or paramedics.

Adequacy of trained first-aiders. This depends on:

− Level of risk from the activities.

− The number of workers.

− Installation remoteness.

First-aid equipment:

− First-aid kit supplies.

− Specialist treatments.

− Recovery room.

− Automatic external defibrillators (AEDs).

Medical Evacuation and Back Up

Procedures for evacuation need to be developed and would consider:

Health risk to the patient:

− Urgency of the transfer.

− Extra risks posed by the transport itself.

Scale of the emergency:

− Single versus multiple casualties.

Resources required and available:

− Vehicle vehicle/vessel/craft:

− Capable of accommodating and securing the patient.

− Fitted with medical equipment.

− Accompanying trained personnel.



Principles of Escape, Evacuation and Rescue

Escape routes should be designed to allow people to escape to a place of safety as quickly as possible. They should therefore be:

Wide enough.

Sufficient in number for the number of personnel and foreseen emergency scenarios:

− With alternative routes in case one route is blocked by fire/smoke.

Protected against the effects of fire/explosion, by:

− Position.

− Special fire protection.

Clearly designated and illuminated.

Maintained clear of obstructions.

Evacuation

Onshore facilities:

− Evacuation off-site is easily achieved by walking or land-based transport.

Offshore evacuation options are:

− Primary method:

− Normal non-emergency method, e.g. by ship if transport to the installation is normally by ship.

− Secondary method:

− Backup method, e.g. lifeboat, situated close to the temporary refuge and launched from the installation.

− Tertiary methods:

− Personal equipment such as lifejackets, liferafts and survival suits.

Recovery and Rescue

Recovery from the sea will be required when:

A tertiary evacuation method has been used.

A helicopter has had to ditch into the sea.

Someone has fallen into the sea from the installation.



Certain secondary evacuation methods have been used:

− Survival craft are not designed to transport personnel to a place of ultimate safety, so require further intervention.

Roles and Operation of Fire Teams

Onshore Installations

Structure typically consists of the following roles:

Incident Controller (IC)

− Site manager or very experienced supervisor.

− Takes control of the incident.

− Determines if an incident is serious and initiates the emergency plan.

− Assumes some Main Controller (MC) responsibilities, if they are absent, to ensure:

− External emergency services are alerted.

− Alarms have been activated and warnings given.

− Plant shut-down and evacuation.

− Key personnel are summoned.

− Co-ordinates incident response activities.

− Establishes and maintains communications.

Main Controller (MC)

− Site manager or offshore installation manager.

− Keeps the incident under review as it develops.

− Makes sure casualties are being treated.

− Liaises with external agencies/sources.

− Controls traffic.

− Keeps a record of the development of events and decisions made:

− Preserving evidence.

− Arranges welfare needs.

− Deals with the media.

− Recovery and cleanup of the area/plant afterwards.



Offshore Installations

Offshore Installation Manager (OIM)

− In overall charge.

− Assisted by:

− Two on-scene commanders (drilling and process).

− Permit controller.

− Radio operator.

− Offshore Installation Supervisor (OIS).

− Direct contact with onshore and the coastguard.

Training and Drills

All site personnel should receive basic instruction on induction:

− Raising the alarm.

− Evacuation routes.

− Where to muster.

− Use of any emergency life-saving equipment.

− Basic first-aid.

Those with specific responsibilities should receive additional training in topics related to their duties:

− Fire team members:

− Fire behaviour.

− Fire-fighting techniques.

− Fire extinguishment.

− Use of breathing apparatus.

− Search and rescue.

− Communications equipment.

− MCs, ICs, OIMs, and OISs:

− Analysing incidents/decision making.

− Adequate evidence recording.

− Specialist fire team training.



− Control room operators:

− Operational emergencies.

− Radio operation during emergencies.

− Helideck crew:

− Helideck emergency training.

Refresher training.

Drills – simulations of real emergency events:

− ‘Table-top’ theoretical exercises.

− Full-scale ‘realistic’ exercises.

Liaison with External Support Agencies and Resources and Emergency Services

External agencies that may be needed include:

Fire brigade.

Ambulance.

Coast guard.

Police.

Air ambulance.

Local municipal authority.

Health authority.

Environmental regulator.

Safety regulator.




Short Questions

1. (a) Give the meaning of the following terms. (i) Active fire protection. (2) (ii) Passive fire protection. (2) (b) Outline TWO examples of the use of passive fire protection. (4) 2. Liquefied petroleum gas (LPG) is stored under pressure to retain its liquid state. (a) Identify TWO types of fire that may result from loss of containment of an

LPG storage vessel. (4) (b) Outline measures that could be used for fire protection of an LPG storage

vessel. (4) 3. Leak and fire detection systems are an important aspect of fire protection in the oil

and gas industry. Outline the measures to improve and maintain the effectiveness of such systems. (8)

4. (a) Outline the THREE options available for offshore evacuation. (6) (b) Give TWO examples of circumstances where sea recovery may

be required. (2)

Long Question

1. (a) Outline the THREE elements of a strategy to prevent major accidents. (6) (b) Outline the typical content of an Emergency Response Plan (ERP). (14)




Short Questions

1. (a) (i) Active fire protection (AFP): Equipment, systems and methods.

Used to control, mitigate and extinguish fires.

(ii) Passive fire protection (PFP): Coating or cladding arrangement or freestanding system.

Provides thermal protection to restrict the rate at which heat is transmitted to the object or area being protected.

(b) On fire barriers (i.e. structures, such as walls, designed to stop fire transmission between different protected areas/compartments).

To protect load-bearing structures (like columns) supporting key areas such as accommodation blocks.

To protect critical equipment/components.

(Only two were required.)

2. (a) Pool fire:

− Occurs when a flammable liquid leaks from a vessel or pipeline to form a fluid reservoir, which then ignites.

Jet fire:

− Can occur following the rupture of a pressurised vessel and/or gas line.

(b) Keep the vessel sufficiently cool (active fire protection):

− Discharge water onto the vessel at a sufficient rate to prevent failure.

Protect the vessel from radiant heat (passive fire protection):

− Burial, mounding or insulating coatings.

3. Adequate number of detectors.

Suitable location.



− Local air flows and the density of the gas.

Maintenance/testing:

− Fault detection circuit should be incorporated.

Uninterruptible power supply:

− In the event of power failure, the protection is maintained.

Manual backup:

− Supplement with manual call points.

Minimisation of false alarms:

− If the detector initiates some control action (such as a shut-down) to reduce the potential for false alarms, a voting system can be incorporated (i.e. several detectors are required to activate to set off the alarm and subsequent control action).

Zoning:

− Detectors wired together into groups/zones so that they trigger a zone alarm on the fire alarm panel.

4. (a) Primary method:

− Normal non-emergency method, e.g. by ship if transport to the installation is normally by ship.

Secondary method:

− Backup method, e.g. lifeboat, situated close to the temporary refuge and launched from the installation.

Tertiary methods:

− Personal equipment such as lifejackets, liferafts and survival suits.

(b) A tertiary evacuation method has been used.

A helicopter has had to ditch into the sea.

Someone has fallen into the sea from the installation.

Certain secondary evacuation methods have been used, e.g. survival craft are not designed to transport personnel to a place of ultimate safety, so require further intervention.



Long Question

(a) Identification of an installation as a major hazard installation:

− Notification to the authorities based on the type of activity and/or inventory of hazardous substances.

Prevention and control:

− Assess the likely risks and put in place effective measures to control them

Mitigation to minimise the effects of a major accident:

− Emergency planning.

(b) Specific foreseeable emergency situations (or types):

− Their likely scale and consequences.

Organisational roles, authority, responsibilities and expertise:

− Emergency response team, incident command structure.

Emergency response actions/procedures:

− From detection and raising the alarm to the point at which the emergency has been controlled and all personnel are in a ‘place of safety’.

Provision of sufficient resources:

− People (shift work coverage, equipment, materials) and specialised emergency response equipment needed in an emergency control centre.

Evacuation procedures:

− The need to establish and maintain evacuation routes and provide for evacuation to a safe place away from the installation.

Communications.

− Between emergency responders (e.g. by radio), internal and external (regulatory) incident reporting, calling external help (escalation) and dealing with the media.

Training for personnel and drills to test the plan:

− Training to maintain readiness of the response team and other workers and liaising with external agencies such as hospitals, the coastguard and regulators.



Element 5: Logistics and Transport Operations Marine Transport

The oil and gas industry uses an array of marine vessels and structures:

FSO - Floating Storage and Offloading Unit

− A floating hull fitted with oil storage tanks.

− A facility to transfer oil to tankers.

− Many FSOs are old, converted supertankers.

FSU - Floating Storage Unit

− Can either be the same as an FSO or transfer the oil by pipeline to a land-based facility.

FPSO - Floating Production, Storage and Offloading Unit

− Receives crude oil from wells.

− Processes the oil (separation of oil, gas and water).

− Stores and offloads it.

LNG FSRU - Liquefied Natural Gas Floating Storage and Regasification Unit

− Receives LNG from other vessels.

− ‘Regasifies’ the LNG (i.e. converts the liquid back into gas).

− Distributes it via pipelines to onshore facilities.

Hazards of Vessels and Working Over Water

As well as the intrinsic dangers associated with planned operations on board and beneath such vessels, there are the specific issues of:

Extreme environmental conditions.

Accelerated wear and corrosion.

Collisions with other vessels and structures.

The intrinsic hazards of the substances.



Oil/LNG transfer operations – which, again, could result in environmental damage (oil spills). We will look at loading/unloading operations later.

Personnel transfer operations.

Drilling rig hazards.

Lone working.

Personnel falling overboard.

Piracy.

Loading and Unloading of Vessels at Marine Terminals

The main hazards associated with floating production, storage and offloading units (FPSOs) include:

Leaks of gas and/or oil arising from:

− Blowouts.

− Pipeline leaks.

− Process leaks.

Non-process incidents such as:

− Fires.

− Chemical spills and leaks.

Marine events such as:

− Collisions of supply, stand-by and support vessels.

− Collisions with other vessels.

− Capsize or grounding.

Extreme loadings due to wind or waves.

Structural failure due to:

− Fatigue.

− Design error.

Failure of derricks, cranes or other equipment.

Dropped objects during:

− Construction.



− Crane operations.

− Cargo transfer.

− Drilling operations.

Transport activities (crew changes/in-field transfers):

− Helicopter crash or fire during refuelling.

− Capsize of crew boats or accidents to personnel during transfer.

Construction accidents:

− Onshore or offshore work.

− Marine installation.

− Commissioning activities.

− Pipe laying.

Diving accidents.

Slips and trips.

Precautions for loading and unloading of vessels at marine terminals include:

Ship securely moored.

Agreed loading/off-loading plan.

Precautions to avoid ingress of flammable vapours.

Ship-to-terminal connections fitted with an emergency release.

Precautions to avoid misconnection of lines.

Hoses inspected for defects.

Hoses/loading arms positioned to avoid placing undue strain on components.

Weather monitored before and during the operation (operation suspended if high winds or electrical storms are expected).

Crews keep watch for leaks during the operation.

Precautions against electrical discharge.

Co-ordinate activities (or take precautions).



Control of Marine Operations, Certification of Vessels, Inspection and Approvals

Certification/Approval

Depending on the vessel, it would need certificates of:

Safety construction.

Oil pollution prevention.

Loadline.

Tonnage.

Mobile offshore drilling unit (MODU) safety.

Shipboard safety management.

Class.

On-board equipment such as cranes.

Master and crew competency.

Inspection

To maintain Class certification, ships must undergo periodic inspection by the classification society.

Roles and Responsibilities of Marine Co-ordinators, Masters and Crews

Safety roles and responsibilities include:

Marine Co-ordinator

− Co-ordinates all the activities related to a vessel’s arrival, mooring, cargo loading/discharge, and departure.

− Liaises with other functions when vessels require annual/special independent inspections.

Ship’s Master

− Ultimate authority; responsible for seaworthiness and safety of the vessel.

− Responsible for the safe navigation of the ship/continued safety of crew and cargo.

− Keeps accurate records/logs of incidents (collisions, pollution).



Deck Crew

− Chief Officer/First Officer – maintenance (fire-fighting equipment), supervision and training of deck crew, cargo (charging/discharging and cleaning tanks).

− Second Officer – vessel navigation.

− Third Officer – safety; in charge of the safety equipment.

Personnel Transfers and Boarding Arrangements

Typical methods of transfer to marine vessels and structures each have principal hazards:

Helicopter:

− Crash on land or water.

Transfer basket:

− Failure of lifting equipment/fall from basket.

Gangways, bridges and accommodation ladders:

− Failure of equipment or sudden movement.

Rope ladder (for pilot transfer):

− Failure of ladder or fall from ladder.

Personal Protective Equipment Suitability

The nature of the task and its associated risk will determine the selection, suitability and appropriateness of the PPE to be worn, which could include:

Safety boots.

Boiler suits/overalls.

Gloves:

− Cotton rigger’s gloves for general work.

− Specialist gloves, e.g. for welding or working with chemicals/oils.

High-visibility jackets.

Goggles.

Hearing protection.

Harness and lanyard.



Respirators, breathing apparatus.

Visors/face shields.

Anti-static/sparkproof clothing.

Safety helmets.

Inflatable lifejackets.

Survival suits.

Diver Operations

Diving can be categorised into:

Surface supplied diving:

− Diver has air supplied via hose from a diving support vessel or installation on the surface.

Self-contained underwater breathing apparatus (SCUBA):

− Diver carries their own air supply in tanks on their back.

− Gives more freedom to the diver.

− More limited air supply.

Hybrid system (sometimes called mobile (or portable) surface supplied diving):

− A mobile system which adds some of the flexibility inherent in SCUBA, but the air is surface supplied.

Diving operation management consists of four steps:

1. Compliance

− All parties should comply with all applicable national, international, industry and company/contractor requirements for the diving operation.

2. Planning

− The diving operation should be properly planned, including:

− Agreeing communications, roles and responsibilities.

− Agreeing the scope of the job to be done.

− Identifying likely hazards and assessing risks.



3. Execution

− Site rules must be followed/developed:

− On-site risk assessment and toolbox talk.

− Safety briefings.

− Use of formal permit-to-work/permit-to-dive system to control the dive.

4. Measuring and Improving

− Review of the operation, any incidents and what lessons can be learned.

Land Transport

Road Tankers

UN Classification and Transport of Hazardous Materials (Transport of Dangerous Goods)

Oil and gas products such as petrol are classified as dangerous goods.

Carriage by road involves the risk of traffic accidents and loss of containment due to:

− Collisions (with vehicles, storage vessels).

− Spillage of the goods (including during transfer).

These may lead to effects such as fire, explosion, injury/death, ill-health and environmental pollution.

Transport of dangerous goods is regulated by national laws and international agreements, the rules depending on the mode of transport. The rules are generally aligned with recommendations issued by the United Nations (UN).

The UN system assigns a class, a description and a four-digit number to dangerous goods.

Dangerous goods carried in road tankers need to be marked and placarded with a system of:

− Hazard diamonds.

− Orange plates.

− UN number and hazard codes.



Protection of Plant Against Vehicles Striking Plant

Vulnerable plant and equipment (bulk storage tanks) should be protected from vehicle collision damage by:

− Position.

− Barriers.

Driver Training

ADR (European Agreement Concerning the International Carriage of Dangerous Goods by Road) requires drivers of tankers carrying dangerous goods to:

− Attend a vocational course of instruction (theory and practice).

− Sit an externally assessed examination (for the classes of goods being carried).

The course covers:

− General aspects of dangerous goods transportation.

− Tanker-specific issues, such as:

− Vehicle behaviour (load movement/surge).

− Specific vehicle requirements.

− Filling and discharge.

− Specific rules (approval certificates, marking, placarding).

Filling Road Tankers

Involves the risk of fire and explosion if a flammable mixture of fuel and air can be generated above the explosive limits in the presence of an ignition source.

Consequently, control measures need to be in place to:

Prevent the formation of a flammable mixture of fuel and air:



− Vapour return systems to reduce flammable vapour release.

− Adequate tank space to prevent spillage through overfilling.

− Level monitoring with alarms.

− Nitrogen blanketing of the road tanker and the bulk storage tank.

− Monitoring equipment to detect leaks from the tank and associated (buried) pipework.

− Strict operating procedures to prevent leaks and spills.

Control potential ignition sources:

− Prohibition of smoking.

− Zoning of the filling area and electrical equipment appropriate for that zone.

− Reduce the risk of ignition by static electricity by:







− Avoiding the use of filters or installing filters far enough upstream of discharge points to allow adequate time for any static generated to leak away.

− Use of antistatic footwear and clothing.

− Earthing of pipeline, vehicle and tank.

− Electrical bonding of all pipe joints and of the pipeline to the tanker.

Deal with emergencies:

− Fire extinguishers to deal with any small outbreaks of fire on, or in the immediate vicinity of, the fuelling unit.

− Dry sand or other absorbent material to aid the clearing up of small leaks or spills.



There are safety implications in the two methods of loading road tankers:

‘Top’ filling:

− Can create ‘splash’, aerating the substance and creating a large electrostatic charge.

− Allows the release of vapours.

− Requires the driver to work at a height on the top of the tanker.

Consequently:

− Fill pipe should touch the bottom of the tanker compartment.

− Vehicle should be earthed.

− Driver should be protected from a fall at height.

‘Bottom’ filling:

− Alleviates the problem of vapour escape.

− Relies on pressure venting and relief devices to be functioning properly.

− Is the main method used for loading petrol in order to:

− Facilitate vapour recovery to prevent the release of hydrocarbon vapours.

− Avoid the need to access the top of the tanker.

Consequently:

− Overfill protection system needs to be effective.

− Tanker compartment needs to be correctly sized for the cargo.

Traffic Management

On-Site

The principles for on-site management of traffic include:

Minimise:

− Bends/junctions.

− Steep gradients.

− The need for reversing.

Pedestrian and vehicle segregation:

− Clearly designate areas for pedestrian walkways and crossing points.



Clear signage:

− Warning of speed limits, obstructions, allowable width/height.

Well lit during hours of darkness.

Wide enough for the vehicles:

− Consider one-way systems.

Enforce speed limits.

Protect vulnerable plant with barriers.

Designed with plenty of space for off-loading.

Dedicated tanker off-loading points:

− Emergency facilities.

− Environmental protection.

Security access gate/sign in.

Routes

Consideration of the security of dangerous goods is a specific requirement of UN Recommendations/ADR. Routes should therefore be planned to:

Ensure suitability for tanker use.

Minimise security threat (terrorism, theft) to the valuable load being carried.

Rail

Rail transportation of petroleum products:

Involves tank cars and tank containers.

Has similar provisions to those for road transport based on UN recommendations.




Short Questions

1. Identify the main hazards associated with floating production, storage and offloading units (FPSOs). (8)

2. Identify FOUR methods of transfer to marine vessels and structures AND their

principal hazards. (8) 3. Identify the safety roles and responsibilities of: (a) The marine co-ordinator. (2)

(b) The ship’s master. (3)

(c) The deck crew. (3)

4. Identify: (a) TWO methods of filling road tankers. (2)

(b) The safety implications of EACH method. (6)

Long Question

1. Filling road tankers involves the risk of fire and explosion. Safety measures aim to prevent the formation of a flammable mixture of fuel and air, control sources of ignition and deal with emergencies.

Identify the controls that should be in place to achieve these aims. (20)




Short Questions

1. Leaks of gas and/or oil (blowouts, pipeline leaks, process leaks).

Non-process incidents (fires, chemical spills and leaks).

Marine events (collisions of vessels, capsize or grounding).

Extreme loadings due to wind or waves.

Structural failure (fatigue, design error).

Failure of derricks, cranes or other equipment.

Dropped objects during construction, crane operations, cargo transfer or drilling operations.

Transport activity incidents (helicopter crash/fire during refuelling, capsize of crew boats or accidents to personnel during transfer).

Construction accidents (onshore or offshore work, marine installation, commissioning activities, pipe laying).

Diving accidents.

Slips, trips.

2. Helicopter:

− Crash (on land or water).

Transfer basket:

− Failure of lifting equipment/fall from basket.

Gangways, bridges and accommodation ladders:

− Failure of equipment or sudden movement.

Rope ladder (for pilot transfer):

− Failure of ladder or fall from ladder.



3. The marine co-ordinator:

Co-ordinates all the activities related to a vessel’s arrival, mooring, cargo loading/discharge, and departure.

Liaises with other functions when vessels require annual/special independent inspections.

The ship’s master:

Has ultimate authority; is responsible for seaworthiness and safety of the vessel.

Is responsible for the safe navigation of the ship/continued safety of crew and cargo.

Keeps accurate records/logs of incidents (collisions, pollution).

The deck crew:

Chief Officer/First Officer – maintenance (fire-fighting equipment), supervision and training of deck crew, cargo (charging/discharging and cleaning tanks).

Second Officer – vessel navigation.

Third Officer – safety; in charge of the safety equipment.

4. (a) ‘Top’ filling.

‘Bottom’ filling.

(b) ‘Top’ filling:

− Can create ‘splash’:

− Aerating the substance and creating a large electrostatic charge.

− Allowing the release of vapours.

− Requires the driver to work at a height on the top of the tanker.

‘Bottom’ filling:

− Through a closed system – therefore it alleviates the problem of vapour escape.

− Relies on pressure venting and relief devices functioning properly.

− Overfill protection system needs to be effective.

− Tanker compartment needs to be correctly sized for the cargo.



Long Question

1. Prevent the formation of a flammable mixture of fuel and air:

− Vapour return systems to reduce flammable vapour release.

− Adequate tank space to prevent spillage through overfilling.

− Level monitoring with alarms.

− Nitrogen blanketing of the road tanker and the bulk storage tank.

− Monitoring equipment to detect leaks from the tank and associated (buried) pipework.

− Strict operating procedures to prevent leaks and spills.

Control potential ignition sources:

− Prohibition of smoking.

− Zoning of the filling area and electrical equipment appropriate for that zone.

− Reduce the risk of ignition by static electricity by:







− Avoiding the use of filters or installing filters far enough upstream of discharge points to allow adequate time for any static generated to leak away.

− Use of antistatic footwear and clothing.

− Earthing of pipeline, vehicle and tank.

− Electrical bonding of all pipe joints and of the pipeline to the tanker.

Deal with emergencies:

− Fire extinguishers to deal with any small outbreaks of fire on, or in the immediate vicinity of, the fuelling unit.

− Dry sand or other absorbent material to aid clearing up small leaks/spills.



And Finally... Hopefully, this guide has provided you with relevant practice questions as well as some ideas for tackling them. It should also have shown that the questions are straightforward, but that it is vital that you READ THE QUESTION and answer the question that is written (not the one that you want it to be!).

In order to do well in the exams, it is really important to practise as many exam questions as possible – the Examiner’s Reports for previous exams can be purchased from NEBOSH (0116 263 4700) or online at www.nebosh.org.uk. These Examiner’s Reports do not provide model answers, but nevertheless highlight important points that should have been included in your answer.

Lastly, don’t panic about the exam, but do ensure that you are prepared – you want to make sure that all your hard work will be rewarded.

Good Luck!


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