UCL ESTATES
Compressed Gas
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Compressed Gas
›   Introduction
UCL uses and stores a variety of compressed gases. Cylinders of compressed gases are used in connection with engineering maintenance work and the storage of refrigerant gases. When compressed gas cylinders are introduced into a work area or building for the first time e-mail fire@ucl.ac.uk with details of the type of gas, number of cylinders and the location where they will be used and stored. This information will be used by the Fire Safety Team to update the fire and rescue information packs available in the Premises Information Box.

›  Acetylene
UCL Estates does not permit the use of Acetylene.



›  Quick Links to Contents
The purpose of this guidance is to ensure those responsible for the storage, location and use of compressed gases in cylinders are familiar with the requirements.

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›  Training
All staff must be trained in hazards and correct handling procedures for compressed gas



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›  Management Responsibilities
Managers are required to ensure that all staff are fully conversant with the correct procedures when using pressure regulators. (For cylinders without hand wheel valves, the correct cylinder valve keys should be kept readily available, e.g. on the valve).


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›  Personal Protective Equipment
  • Use stout gloves (preferable textile or leather) and protective footwear when transporting compressed gases.
  • Use respirators and face protection etc, when changing regulators on cylinders of toxic gases
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›  Storage
  • All cylinders should be stored upright and secured to prevent them falling, do not prop any cylinders against a wall or bench but use a suitable cylinder stand.
  • Stored cylinders should be segregated by type - All cylinders must be properly labelled and colour coded EN1089-3
  • Full cylinders should be stored separately from empty cylinders and be clearly identified, empty cylinders should be returned to the supplier on a regular basis.
  • Where necessary, provide fireproof partitions / barriers to separate / protect cylinders;
  • Storage areas must be of fire resisting material and so designed and situated, that in the event of fire, the cylinders do not present a significant fire risk to the building.
  • Protect storage facility from mechanical damage;
  • Cylinders must only be stored in a purpose - designed area used only for compressed gas. The gas storage facility should be sited in a well ventilated, preferably in the open, ideally with some weather protection (cold weather from accumulation of ice and snow, and in hot weather from the direct rays of the sun) The floor surface should be well drained and smooth to prevent corrosion of cylinders or instability
  • No artificial heat is to be allowed in stores where compressed gas cylinders are stored (boilers, radiators and well away from combustible material and open flame).
  • Cylinders and fittings must be kept away from all sources of contamination to prevent grit, dirt or any type of oil, grease and water from entering cylinder valves. They must be kept clear of all corrosive materials/environments.
  • Personnel must not smoke, wear clothes heavily contaminated with oil/grease, or have any naked flame in any place where compressed gases are stored.
The UCL Fire Technical Note No 097 prescribes requirements for storage cupboards housing flammable substances or liquid.



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›  Location of Cylinders
  • Compressed gas cylinders should be stored away from fire risk (fire loading - i.e. packaging materials, 5m plus) and away from sources of heat and ignition. The cylinder storage must be designated a NO SMOKING AREA and signed 'Caution Compressed Gases'.
  • Depending on the length of pipe run, locate cylinders outside (for hazardous gases valves installed within the workplace can be used as remote control of the main supply from the cylinder in the event of an emergency).
  • Site cylinders so they cannot become part of an electrical circuit, all storage facilities must be electrically bonded/earthed;
  • Securely clamp, or firmly held in position cylinders on installation. (Unless otherwise specified cylinders containing liquefied or dissolved gases must be stored and used upright);
  • Storage areas should be well defined and located in the open air where there is good natural ventilation. Storage in a building is not recommended and should not be considered for new locations for cylinder stores.
  • Storage locations for cryogenic, liquefied and heavier than air compressed gases, e.g. argon, carbon dioxide and liquid nitrogen, should be sited with due regard to the dangers of seepage into drains, basement areas and underground conduits.
  • Oxygen should be stored at least 3 m away from fuel gas cylinders (flammable gases - i.e. propane, hydrogen or separated by a full height separation wall, the wall must be of 30 minute fire resisting construction and constructed of materials such as solid concrete or masonry. The wall should not be less than 2 m in height.
  • Liquefied Petroleum Gas (LPG) cylinders in excess of 50kg total capacity should not be stored within 3 m of any compressed gas cylinders including acetylene (see additional guidance, HSE Guidance CS4 for LPG requirements and BCGA Code for hydrogen storage). LPG storage in small quantities must have 1 metre clear area all round the storage area or be firewalled.
  • Toxic and corrosive gases (i.e. Ethylene Oxide etc) should be stored separately from all other gases (refer to the materials safety data sheet and the supplier will advise on detailed requirements)
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›  Internal Storage
Gas Manufacturers and the British Compressed Gases Association (BCGA) do not recommend indoor storage of compressed gas cylinders. However, where indoor storage cannot be avoided, only a small number of cylinders may be stored.

A risk assessment must be carried out to identify the necessary risk control measures and emergency procedures to ensure safe operation of the facility. Mechanical ventilated systems must be compatible with the gases stored.

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›  Use
  • Fit approved cylinder pressure regulators, selected to give maximum pressure on the reduced side commensurate with the required delivery pressure. (The regulator and all fittings upstream of it must be able to withstand at least the maximum cylinder pressure).
  • Fit in-line flame arresters for flammable gases and eliminate ignition sources;
  • Use compatible pipe fittings. (Flammable gas cylinders have valves with right hand threads; cylinders for oxygen and non-flammable gases, except occasionally helium, have valves with right-hand threads. Certain liquefied gas cylinders have two supply lines, one for gas and one for liquid, dependent on cylinder position).
  • Do not use oil, grease or jointing compounds on any fittings for compressed gas cylinders;
  • Fit an excess flow valve to the outlet of a regulator, select to allow the maximum required gas flow;
  • Turn off gas supply at the cylinder at the end of days use;
  • Consider the need for gas detection / alarms, e.g. for hazardous gases left in use out of normal hours;
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›  Hoses
  • Only the best quality hoses are to be used. Low quality hose tends to harden, crack and leak. Low quality hoses have been known to catch fire when oxygen is passes through it.
  • Hoses must be firmly attached to the blowpipe and other connections by approved clips (jubilee clips are not suitable).
  • Lengths of hose are supplied with the ends firmly attached to suitable ferrules having screwed unions suitable for connecting to standard regulator outlets and blowpipe inlets. These must be used in preference to any other hoses.
  • Accidents occur due to leakages or the supply hose becoming loose or blown off. Hoses and connections must be formally examined every 3 months. A record of inspections must be kept.
  • Lengths of hose must be joined by means of approved BCGA connecting fittings when more than a standard length is required. Do not use unnecessarily long lengths of hose.
  • Never use rubber or plastic connections from cylinders containing toxic gases
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›  Valves and Regulators
  • Never try to re-fill cylinders;
  • Only use correct key. Do not extend handles or keys to permit greater leverage; do not use excessive force, e.g. hammering when opening / closing valves or connecting / disconnecting fittings.
  • Never force connectors that do not fit. Where cylinders are connected to manifolds or headers, such manifolds must be of proper design and equipped with one or more pressure regulators, and flash back arrestors.
  • The pressure regulator must be fully closed before opening the cylinder valve. This valve can then be opened slowly until the regulator gauge indicates cylinder pressure but should not be opened wider than necessary.
  • The cylinder valve must be opened slowly.
  • Cylinder valve spindles always have right hand threads, irrespective of whether the cylinder contains a fuel gas or a non-combustible gas.
  • The cylinder valve must be closed sufficiently to shut of the gas. Excessive force must not be used.
  • Welding and cutting apparatus must not be used unless automatic pressure regulators are fitted to the oxygen and fuel gas cylinders.
  • Do not rely on the needle valve, as this does not prevent a reverse flow of gas towards the cylinders.
  • Before any regulator is put onto a full cylinder, the operator must always release the adjusting screw for regulating the pressure of output; otherwise there is a risk of damage to the regulator.
  • The threads on regulators and other auxiliary equipment must be the same as those on the cylinder valve outlets.
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›  Transport
  • Transport gases in specially designed trolleys
  • A cylinder dolly should be used for transporting large compressed gas cylinders.
  • Do not roll or drop cylinders from height, never lift cylinders by the cap;
  • Cylinders must not be lifted with magnets or chains, a rope or nylon sling must be used to lift one cylinder.
  • Never lift more than one cylinder at a time and ensure the sling is properly adjusted to prevent slipping.
  • Cylinders must never be transported with the regulators and hoses attached, unless a proper trolley or carrier is used.
  • When transporting by trolley, the cylinder valve must be shut before the cylinder is moved.
  • Cylinders of compressed gas should not be transported by vehicle on public road without proper classification as required by the dangerous goods road regulations and should only be transported in an approved vehicle for the type of gas. It is recommended that competent contractors are used to move cylinders by road when needed.
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›  Periodic Checks
  • Ensure no gas discharge when gauge reading is zero;
  • Ensure reading on gauge does not increase as the regulator valve is closed;
  • Check for 'crawl' due to wear on the regulator valve and seat assembly;
  • Ensure no leak between cylinder and regulator;
  • Overhaul regulators on a 3 - 6 month basis for corrosive gases, annually or as manufacturers recommendations for others;
  • Valves and fittings must not be lubricated and jointing compound must not be used to prevent leaks.
  • Inspect condition of cylinders regularly, especially those containing hazardous gases (i.e. corrosives).
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›  Gauges
No attempt must be made to use pressure gauges other than those recommended by the supplier.


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›  Emergency Arrangements
  • In the event of fire, cylinders must be easily removable.
  • Should a cylinder become accidentally over heated or damaged, the suppliers must be notified immediately and the cylinder must be taken out of service.
  • Oxygen has no smell and whilst it does not burn, it supports and accelerates combustion. Ordinary clothing and more flammable materials such as oil can be ignited, and will burn fiercely in oxygen or where the atmosphere has been enriched with oxygen.
  • Take care to avoid leakages. Always test with 2% Teepol in water (liquid soap), or a recognised brand of leak detection spray. Never check for leaks with a naked flame.
  • In a confined space a small amount oxygen may create a dangerous condition which will cause explosion or fire from a spark or naked flame.
  • Cylinders within workplaces should be restricted to those gases in use. Specially designed compartments with partitions may be required to protect people in the event of explosion. Take into account emergency exits, steam and hot water systems, the proximity of other processes etc. consider the possibility of dense gases accumulating in drains, basements, cable ducts, lift shafts etc;
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›  Confined Space Working
  • When compressed gases are used in a confined space - both ends of the hoses must be broken to atmosphere when the equipment is left unattended for extended periods.
  • Use only the suppliers keys for operating cylinder valves.
  • Do not increase the leverage of keys or employ long leverage spanners or badly worn keys.
  • Do not attempt to get gas from cylinders with broken spindles, otherwise valves may be damaged and the cylinder rendered useless.
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›  Disposal
If a cylinder is no longer needed it should be returned to the supplier. If this is not possible then contact Facilities Services via Customer Services Centre on Ext. 30000.


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›  Other Related Information/Documentation




Further guidance can be found at: The UCL Fire Technical Note No 097 prescribes requirements for storage cupboards housing flammable substances or liquid.

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