Health & Safety Executive / Local Authorities Enforcement Liaison Committee(HELA)

Local Authority Circular

Subject: Pressure Systems LAC Number: 66/8

Open Government Status: Open Keywords: Gas Cylinders

Revised: September 2000 Review date: September 2005To: Directors of Environmental Health/ Chief Environmental Health Officers of London, Metropolitan, District and Unitary

Authorities and Chief Executives of County Councils.

For the attention of: Environmental Services / Trading Standards / Fire Authorities / Other

This circular gives advice to local authority enforcement officers

PRESSURE SYSTEMS SAFETY REGULATIONS 2000 ISSUES OFINTERPRETATION

INTRODUCTION

1 Enforcement officers will wish to be aware of these interpretations as supplementing existingguidance so that a consistent approach to enforcement can be taken nationally.

2 References are to individual regulations and, where appropriate, the ACoP relating to thoseregulations.

3 The information is intended to give practical guidance to enforcement officers rather than to setrigid standards to be followed in every case.

COMPETENT PERSONS (reg 2 definition)

4 A "competent person" legally cannot be an individual employee but can be an in−house inspectiondepartment within a user's or owner's company. The in−house department can be staffed by justone individual although larger complements are normal. Such departments must have a properdegree of independence from the operating functions of the company. So, for example, individualswithin in−house inspection departments who carry out functions in addition to theircompetent−person duties, should be separately accountable under their job descriptions for thosecompetent person duties. Individuals should not be subject to commercial or financialresponsibilities which conflict with their competent person duties.

5 As regards the attributes of the person drawing up or certifying the written scheme there is noneed for that individual to be of chartered engineered status provided he/she acts under thedirection and supervision of a chartered engineer, or engineer of equivalent status.

MOBILE SYSTEM (reg 2 definition)

Application of the Regulations to rail tankers transporting LPG

6 The regulations will apply to tankers transporting LPG by rail and the tankers themselves wouldbe defined as "mobile systems".

PRESSURE SYSTEM (reg 2 definition)

7 The definition in reg2 has 3 clauses (a), (b) and (c) which should be read as alternatives.

Domestic LPG installations

8 The Regulations will apply to LPG tanks whilst they are being installed or filled because then thereis "use at work".

RELEVANT FLUID (reg 2 definition)

Steam

9 Hot water above 1100C is a relevant fluid.

10 Pressure systems operating between 1000C and 1100C should be considered by enforcementofficers under the regulations. Users should be asked for clear evidence that such systems do notcontain (and are not liable to contain) steam under foreseeable operating conditions and that thetemperature is not liable to exceed 1100C.

11 If evidence is not forthcoming, the advice of HSE specialists may be necessary if enforcementaction is contemplated (via the ELO).

Aqueous solutions

12 For an "aqueous solution" to be a relevant fluid the liquid must contain dissolved gases whichgenerate pressure above 0.5 bar by the evolution of the gas at either the actual temperature of theliquid or 17.50C.

Methyl bromide

13 Methyl bromide used for fumigation is a relevant fluid and the regulations will apply when itsvapour pressure is greater than 0.5 bar above atmospheric pressure.

TRANSPORTABLE GAS CONTAINER

Distinction between "transportable gas container" and "mobile system"

14 Occasionally, enforcement officers may come across equipment which falls within the definitionof "transportable gas container" but could also be regarded as a "mobile pressure system" for thepurposes of the regulations. When considering these cases, enforcement officers should bear inmind that:

the words "designed to be transportable for the purpose of refilling" have been interpreted byHSE's solicitor to mean that the container so described should be designed so that it can beremoved from its appliance when it is empty and transported to another place where it canbe filled.

15 Advice may be obtained via the ELO in the normal way in cases of doubt.

Transportable cryogenic (deeply refrigerated) gas containers

16 These containers come within the definition of "transportable gas container" because:

(1) the containers are for a relevant fluid; and

(2) the containers are designed to be transported for the purposes of refilling. Thefact that they may occasionally be used for static storage is immaterial.

Chlorine drums

17 Chlorine drums in the UK are typically 864 kg and 1000 kg both of which have capacities below3000 litres. The drums are of mild steel construction either roller−forge−welded or fusion welded.The roll forged drums have inverted ends convex to pressure. There are two internal pipes withexternal stop valves.

18 These chlorine drums should be treated as transportable gas containers and subject to thepositive approval requirements of part V of the regulations.

MARKING OF LOW TEMPERATURE OR INSULATED PRESSURE VESSELS (reg.5(4))

19 Providing that the vessel is marked in accordance with reg 5(4)) it is not necessary for themarking to be readable at all times. If the plate is iced up or covered by insulation and needs to beviewed then the ice or insulation should be removed. Furthermore, the supporting documentation forthe vessel should be available. If it is necessary for the information to be readable at all times, thiscan be achieved by fixing the marking plate to a bracket which is proud of the vessel itself.

IMMINENT DANGER (reg.10)

20 "Imminent danger" can only be declared by a competent person as a result of carrying out theexamination in accordance with the written scheme.

21 If the written scheme only applies to the plant when it is not in use then that would limit the extentof reg 10. If the scheme of examination covers in−service examination then the competent personneed only declare imminent danger if it is discovered during the examination. At all other times, thediscovery of faults in the operational condition of the plant, whether considered to be of imminentdanger or not, comes within the scope of reg 12 on maintenance. In this situation, the competentperson or any other employee would need to comply with HSW Act s.7(b), which would requireco−operation so far as is necessary to enable the employer to comply with reg 12.

EXCEPTIONS (Schedule 2, Part 1)

Refrigeration systems (Exception 18)

22 Specification of safe operating limits for refrigeration plants should be in the form of maximumand minimum coincident pressures and temperatures.

23 The minimum design temperature is an important design criteria which ensures that materialsselected to subzero use in refrigerating systems have the required fracture toughness properties attheir operating conditions to resist brittle fracture.

24 There is an exception from the regulations for any vapour compression refrigeration systemincorporating compressor drive motors (including standby motors) having a total installed power notexceeding 25 kw. The exception would apply to separate systems intended to operate as integratedunits by means of electrical connections to one common controller only if the total power is below 24kw.

Prime movers (Exception 20)

25 Exception 20 excludes prime movers from the regulations. The definition of "prime mover" atsection 176 of the Factories Act 1961 should be used in interpretation. By this route cylinders withan integral piston or ram actuated by steam or compressed air are excepted from the regulations.

Fire extinguishers (Exception 24)

26 Exception 24 relates to portable fire extinguishers with a working pressure below 25 bar at 600Cand having a total mass not exceeding 23 kg.

27 The exception embraces halon fire extinguishers mounted within racing cars and operatedremotely by the driver in the event of an emergency.

Hand−held tools (Exception 25)

28 Exception 25 only applies to parts of a hand−held tool which are pressure vessels and not to thetool itself.

29 The hand−held lance of an oxy−acetylene welding set is not a pressure vessel because it only"contains" a relevant fluid in the sense of directing gases to the flame; there is no storage of gas.

30 The hand−held lance should be considered part of a pressure system as "pipework to which atransportable gas container is, or is intended to be connected".

ASSESSMENT OF INSPECTION ORGANISATIONS (including in−house organisations)

31 Voluntary accreditation scheme for inspection bodies (see ACOP − para 43).

32 The assessment is made by UKAS.

33 If enforcement officers doubt the competency of any inspection body they should consult theELO.