working in excavations procedure - tenderlink safe work practices at all times and review and sign...

SWP 214 - Working in Excavations - Trenches and Shafts Version 3 Issued 12/2/2009 Reviewed 29/7/2013 Uncontrolled when printed

SAFE WORKPLACE PROCEDURE No. 214

Working in Excavations - Trenches and Shafts

Purpose To detail the requirements for persons carrying out excavation works including: the excavation of trenches and shafts. Definitions

o Trench – opening whose length is greater than its depth and the width is less than its length.

o Shaft – any vertical opening whose dimension is less than its depth. o Deep Excavation – means a trench which is deeper than 1.4 metres and a shaft

deeper than 2.0 metres. o Shallow Excavation – means a trench shallower than 1.4 metres and a shaft shallower

than 2.0 metres. o Excavation Supervisor – means a Southern Rural Water employee who has been

nominated by the Area Supervisor/Manager (Headwork/Irrigation/Technical services) to supervise trenching and excavation works after:

1. Completion of an accredited trenching and shoring course (or Mine Managers Certificate)

2. Demonstration of suitable experience in excavation works Responsibilities and Authorities Area Supervisor/Manager

1. Monitor to ensure staff members are following appropriate excavation procedures. 2. Ensure new staff members are provided with information regarding SRW’s

procedures for trenching operations 3. Ensure WorkSafe notification for deep excavations 3 days prior for planned works or

within 24 hours after emergency works has been carried out. Area Coordinator/site manager

1. Ensure individual works are carried out in accordance with the excavation procedure and Risk assessment

2. Ensure the risk assessment is reviewed, updated and signed prior to commencement

3. Ensure that an approved Excavation Supervisor is available to supervise each work site that involves the excavation of trenches or shafts (excluding shallow excavations by hand)

All Employees

1. Follow safe work practices at all times and review and sign safe work method statement

2. Do not enter to a deep excavation until the Excavation Supervisor has assessed the excavation is safe to enter.

3. Do not start or continue to work where the worksite is unsafe. Never work alone in a deep excavation.

4. Alert the Excavation or Site Supervisor, and fellow operators to any hazard or potential danger which may exist from the excavation (e.g. trench movement)


EXCAVATION SUPERVISORS BEFORE COMMENCING - ALL UNDERGROUND SERVICES MUST BE LOCATED WITH THE USE OF DIAL BEFORE YOU DIG or A PRIVATE SERVICE LOCATOR

1. Ensure safe work method statements (risk assessments) are performed for all deep excavations - excluding shallow trenches or shafts that are hand excavated.

2. Ensure deep excavation activities are adequately supervised., 3. Carry out periodic inspections of deep excavations and record the details of such

inspections. 4. Respond immediately to excavation and trenching hazards raised by employees

working in and around the excavation. Investigate these issues and where necessary implement control measures to address them.

5. Ensure employees do not enter a deep excavation before an assessment has been made that the excavation is safe to enter.

OHS Hazards and controls The following table lists common hazards associated with excavation work and examples of control measures:

Potential hazards Examples of control measures

Ground collapse The use of benching or the installation of ground support (e.g. shoring or shields)

Water inrush Pumps or other dewatering systems to remove water and prevent build-up

Falls Ramps, steps or other appropriate access into the excavation (eg. Ladders)

Hazardous manual tasks Rotating tasks between workers

Airborne contaminants (welding gases, sealants, etc.)

Mechanical ventilation to remove airborne contaminants

Buried contaminants (e.g. asbestos) Training to identify buried contaminants and what action to take

Underground services Obtain information from the relevant authorities on the location of underground services

Plant and Equipment Hazards (Being struck by mobile plant or loads)

Exclusion zones, hi-vis clothing and hard hats

Electrocution - machine contacts live wires.

Visual inspection of site – detailed safe work method statement. Use spotter if working in the spotter zone


Training and Competency

1. All deep excavations shall be supervised by an Excavation Supervisor who is required to be present at all times where persons are working in a deep excavation.

2. All shallow excavations shall be supervised by a fully trained operator who has completed an accredited trenching and shoring course.

3. All persons working in deep excavations must have read and understand this excavation procedure and safe work method statement

4. Operators of Load-shifting equipment including the following: o Front end loader / backhoe o Excavators o Dozers o Skid steer loaders o Draglines, cableways / flying foxes

Shall have completed and be issued with a qualification card issued by an accredited training provider, OR an equivalent licence (includes: a valid NSW Licence, Licence from another state, or old Victorian licence)

5. OHS construction induction (redcard)

Procedure General Requirements - All Excavations

1. All persons on site (including those who may be inspecting or visiting) shall wear the following personal protective clothing and equipment: o Safety helmet (hard hat) o Safety footwear o High visibility vest for those working around mobile plant or near roadways.

2. Where an excavation is assessed as a confined space SRW’s procedure, “Entry into Confined Spaces Procedure No. 211” shall be observed and applied.

Shallow Excavations

1. All shallow excavations must be supervised by a competent person (Site Supervisor) who has completed an accredited training course in trenching and shoring. 2. All shallow excavations must be assessed for risks:

o Where mobile plant is used to excavate a documented site safety assessment using SRW’s “Site Safety Risk Assessment and Record of Excavation Inspection” shall be carried out by the Site Supervisor.

o Where hand excavation occurs an informal a Take 5 risk assessment must be carried out. SRW’s “Site Safety Risk Assessment and Record of Excavation Inspection” may be used as a guide.

Deep Excavations

1. All deep excavations must be supervised by an Excavation Supervisor 2. The Excavation Supervisor or Area Coordinator shall notify the Victorian WorkCover Authority of any excavation deeper than 1.4 metres for trenches and 2.0 metres for shafts.

o Planned works - notification is required to be provided 3 days before excavation works are carried out.

o Emergency works – notification shall be provided as soon as possible after the works have commenced but must be within 24 hours of completion of the works.

3. A current copy of the WorkSafe “Notice of Intention to Commence Excavation Operations in Trenches, Shafts and Tunnels” is attached to this procedure OR saved


in the Procedure Management System under Occupational Health & Safety/templates/Template No. 12 - Water Supply - Notice of Intention to Commence Excavation Operations in Trenches, Shafts and Tunnels

4. A documented risk assessment shall be undertaken by the Excavation Supervisor before works commence using SRW’s “Site Safety Risk Assessment and Record of Excavation Inspection”.

5. A Safe Work Method Statement must be completed by the Excavation Supervisors and all person attending the site inducted into the (SWMS) and sign off (SWMS attached to the appendices

6. SRW employees shall not enter a deep excavation until the excavation supervisor has assessed the excavation as safe to enter.

7. Ladders shall be provided and used for access and egress from all deep excavations. For long trenches additional ladders shall generally be required to be provided every 30 metres.

8. Ground support systems or benching / battering shall always be used for deep excavations unless the Excavation Supervisor certifies that they are not required.

References OH&S Act 1985; S 21 Code of Practice Safety Precautions in Trenching Operations 1988 Appendices

o SRW’s “Site Safety Risk Assessment and Record of Excavation Inspection”. o WorkSafe “Notice of Intention to Commence Excavation Operations in Trenches,

Shafts and Tunnels” o Battering examples o No Go Zones o Safe work Method Statement - generic pipeline leak (example)


SITE RISK ASSESSMENT & RECORD OF EXCAVATION INSPECTION

This form must be completed by the Excavation Supervisor Site Address / Location: ………………………………………………………………… Date of Works: …………………………... Type of Excavation: Trench Shaft Tunnel/Bore Open Cut WorkSafe Notified: Yes No N/A Excavation Depth: …………m Width: …………m Length: ………..m

Nature of Ground Yes No N/A

Clay (stiff, firm, soft, greasy) Shale Loam Sandy Rock

Previous Excavation Yes No N/A

Other trenching works

Old Excavations

Possibility of Flooding Yes No N/A

Strom water runoff

Surface water runoff

Swamp/Dam/Reservoir Lake

Drains

Water Courses

Pumps Required

Ground Vibration Yes No N/A

Other construction works

Explosives used

Heavy traffic

Excavation machinery

Close by

Services Located Nearby Yes No N/A

Underground power

Gas Line

Optic cable

Telephone Cable

Dial Before you Dig required

Locator required

Type of Trench Protection Yes No N/A

Battering / Benching

Trench shields

Soldier sets & jacks

Sheeting

No Support required

Excavation / Trench Hazards

Mobile Plant Near Over head Power lines

Yes No N/A

Plant working in No Go Zone

Spotter required

Power Company notified

Plant working in Yellow spotter

zone

Permission from power company

provided

Plant working in Green open area

zone

Complete below if working in a No Go Zone Plant Information Max reach of boom bucket ……………m Proposed working envelope for works: o Height ………………………………...m o Extension ……………………………..m o Slewing width ………………………...m Plant position from power lines: o Directly below ………………………..m o N/E/S/W ……………………………...m Estimated distance plant will be working from power lines: o Vertical ……………………………….m o Horizontal …………………………….m

Terrain Yes No N/A

Flat (no slope)

Minor slop (10 degrees)

Severe slop (10-20 degrees)

Weather conditions Yes No N/A

No wind

Slight wind

Strong wind

Gusty unpredictable

Name of Spotter: ……………………………………

Other safety Controls Yes No N/A

Observer at the top of trench

Barricading required

Traffic signage required

Traffic management required

Entry to confined space

Access ladder required

Asbestos pipe removal

Contractors Employed Yes No N/A

Contractors inducted

Contractors licensed

Personal Protective Equipment (PPE)

Yes No N/A

Hard hats

Safety boots

High visibility vests

Fire extinguisher

Gloves

Reparatory protection

Chemicals Yes No N/A

Chemical used

MSDS provided

Correct PPE provided

Asbestos control plan completed

Contractors equipment inspected

& OK

Site Inspection Record Excessive water in trench Supports damaged/over stressed Tension cracking in surrounding soil Subsidence in surrounding soil Undercutting of trench walls Vandalism PPE being worn Traffic Management/signage in place

Morning Yes No N/A

Noon Yes No N/A

Afternoon Yes No N/A

Comments: …………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… Signature of Excavation Supervisor: …………………………………………………Date completed: …………………………….

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This SWMS is a site-specific statement that must be prepared before any high-risk construction work is commenced.

Person responsible for ensuring compliance with this SWMS:

Date:

High-risk job: Excavation and repair or pipeline clamp

Location:

What are the tasks involved? What are the hazards and risks? How will hazards and risks be controlled?

(describe the control measures and how they will be used)

Think about the worksite and each stage of the project, including preparation and clean-up.

1. working outdoors Working in direct sunlight causing sunburn Wear protective hats and sunscreen on exposed body parts

Flies and insects - bites Use insect repellent before commencing work to prevent distraction

Snakes - bites Visual observation of area before commencing work

Hot weather/cold weather (thermal comfort) o Maintain cold fluid intake on warn days

o Provide shade if possible

o Cold day wear warm clothing and avoid working in the rain (if required appropriate wet weather clothing is required)

2. Traffic control Speeding traffic

Erect men at work sign & appropriate signage to slow traffic and reduce speed (complete a traffic management plan)

Traffic - site worker being hit by a car o Wear high visibility safety vest

o Position witches hats or barriers around work area

o Observe for vehicle traffic before moving from the work site.

Safe Work Method Statement

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3. Site observations Electrical hazards – overhead powerlines o Document height of overhead powerlines…………… o Use a spotter if working in the 3 – 6.4 m zone o No works permitted if work is within the No go zone o Document height of machine ………………………….. o Machine operator must maintain contact with spotter at all

times o Identify and document a safe loading area clear from

overhead hazards ……………………………….

4. Operation of Machinery Operation of machinery o Use a Licensed machine operator only o Perform machine pre-start checklist o Refer to procedure No. 44 – safe operation and

maintenance of Backhoes and excavators

Slipping and falling from machinery when entering and exiting

o Turn off machinery o Always face the machinery when exiting o Use steps and handrails provided (near jump from

machinery) o Maintain a 3 point contact at all times

Burns and explosion from refuelling o Turn engine off o Ensure there are no naked flame in the area – NO Smoking

zone o Use funnel to prevent spillage o Wipe up spillage residue

Machine tipping over - crushing o Warm up machinery before full operation commences o Site inspection before works commences o Level ground surface and stabilise machine before

commencing excavation o Operation of the machinery must only occur when in the

seated position o Seat belt must be on o Bring load close to the excavator before travelling distances

or swinging the load

Machine bucket striking a site worker

o All site personal to wear hard hats o High visibility vest and safety boots/gumboots o Do not stand near machinery when in operation (15 meters

clear)

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5. Excavation Underground hazards – electrical/gas/telecom

o Dial before you dig (Yes/No) o Use accredited cable locator contractor to test the area o Excavate by hand around identified assets

Electrocution – overhead or underground services

o Look up and Live

o Dial before you dig & cable location contractor.

o Have a spotter to observe to works

Striking the concrete pipe with the backhoe

o Have a spotter observe the site when excavation is in

progress

o Stand clear of the operating boom of the machine

o Wear PPE listed above

Trench collapsing Trenching supervisor to inspect the trench before worker enter the trench

Falling in open excavation Install bunting around the top of the trench to define where excavation is located

6. Install a pump to reduce water volume in the trench

Manual handling/ back injury from setting up site pump

o Follow correct lifting techniques/ use 2 people to position pump

o Use excavation machine to lift and manoeuvre pumps

7. Erection and installing trench shield Manual handling the trenching shield o Use the excavation machine to unload the shield components

o Unload in the designated unloading area

Being crushed by the shield o Do not stand or work under the suspended load o Hard hats, Gloves & Safety boots are required o Use approved and inspected lifting gear (chains) o Dogman to sling up loads

8. Pipe clamp repair Pinch or cut hands on sharps objects Wear appropriate gloves to protect hands

Accessing the trench and or falling in the excavation – greater than 2 meters

o Use ladder for access o Install temporary bunting around the excavation area to

prevent falls into the trench

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Worker struck by the Operating Machine or items falling in the trench from above

o Wear hard hat o High visibility vest and safety boots/gumboots o Lower clamps in trench the first the access to unload

clamps o Do Not work under a suspended load

Manual handling/ back injury

Use the excavation machine to lower the clamps into the pit

Clamps hitting someone when lowering Remove all personal from the trench when lowering clamps and equipment

Fitting clamps around pipeline/ Manual handling

o Wear gloves o 2 person lift and use correct lifting techniques

9. Backfill trench Machine striking employee o Wear hard hat o High visibility vest and safety boots/gumboots o Keep clear at all times

10. Site clean up on completion Site damage – reinstate site area o Set up bunting to limit stock access to enable soil to dry and settle

o Dress area with top soil and grass seeds as required o Repair any fence damage that had been caused by eth

works o Clear track damage caused by site machinery

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Safe work method statement (continued)

Steps for filling out

1. Discuss with relevant employees, contractors and Supervisors what work will be high-risk, the tasks, and associated hazards, risks and controls.

2. In the ‘What are the tasks involved?’ column, list the work tasks in sequence to how they will be carried out.

3. In the ‘What are the hazards and risks?’ column, list the hazards and risks for each work task.

4. In the ‘How will the hazards and risks be controlled?’ column, select the hazard or risk and then work through the control levels 1 – 4 from top to bottom. Choose a control measure (and how it is to be used) that is as close to level 1 as is reasonably practicable.

Control levels

1. Eliminate any risk to health or safety associated with construction work.

2. Reduce the risk to health or safety by any one or any combination of the following:

Substituting a new activity, procedure, plant, process or substance

Isolating persons from the hazard, such as barricading, fencing or guard railing, or

Using engineering controls, such as mechanical or electrical devices.

3. Use administrative controls, such as changing the way the work is done.

4. Provide appropriate personal protective equipment.

5. Brief each team member on this SWMS before commencing work. Ensure team knows that work is to immediately stop if the SWMS is not being followed.

6. Observe work being carried out. If controls are not adequate, stop the work, review the SWMS, adjust as required and re-brief the team.

7. Retain this SWMS for the duration of the high-risk construction work.

Persons Required to Carry out Task: Signature Activity

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