Use of Gas Heaters

Created on: 28 Jul 2023

Portable liquefied petroleum gas (LPG) heaters should only be used as temporary measures the event of breakdown of the normal heating system.

Where they have to be used there is a need to recognise the fire, explosion and toxic risks. Circumstances have to be considered individually because conditions in individual premises vary enormously.

If heaters are to be used a risk assessment should be carried out and a written safe system of work should be prepared by a competent person. The employer should ensure that the arrangements detailed in the system of work have been properly implemented.

The fire risk assessment will also require to be reviewed. Since it is foreseeable that the need for emergency heating will arise from time to time, employers should make advance plans.

If, after taking account of all possibilities, it is decided that the heating is to be of the portable LPG variety, several factors should be taken into account. These include: the adequacy of the ventilation, the extent of usage of individual rooms, the existing fire hazard of the building and separate rooms within it and the availability of suitable means of escape.

Additional fire fighting equipment may also be required. Clear written guidance on emergency procedures should be prepared, eg, to cover the possibility of a leakage of gas with or without a fire, or a fire arising from extraneous sources.

Employers should buy equipment from reputable firms. Where equipment is hired it should only be hired from a reputable supplier who has adequate facilities to ensure proper maintenance. Equipment, whether purchased or hired, should conform to British/European Standards.

The manufacturers or suppliers instructions should be taken into account and should be made available to the users of the equipment. Several years may elapse between the need to use the LPG heaters and it is necessary to make suitable arrangements for the long term storage and maintenance of the equipment.

Flame failure devices, atmosphere sensitive devices and gas pressure regulators can deteriorate and should be examined annually by a specialist engineer. The equipment should also be examined following a spell in storage prior to use.

In general appliances fuelled by butane rather than propane are preferred for indoor use as butane has a lower pressure. Large industrial mobile heaters, for example those fuelled by 47kg propane cylinders should not normally be used while premises are being occupied for educational purposes.

Even when heaters designed for use with cylinders of no larger than 15kg capacity are used the possibility of students tampering with the equipment should be realised. Close supervision may be necessary.

Storage of Cylinders

LPG cylinders (including empty ones) not connected to an appliance or heating appliance should be stored outside and where possible in a secure cage or compound. Cylinders should always be kept upright and protected from damage, eg by chaining unstable cylinders in racks or special trolleys.

It is not essential to remove a cylinder from an appliance for short term storage purposes provided the valves on the appliance and on the cylinder has been turned off.

One reason for this is because repeated making and breaking of connections may increase the possibility of a faulty connection being made.

Keeping of Heaters in Rooms

Heaters should be brought into a room only when required for immediate use and should be removed when normal heating is restored.

The number of heaters per room, and where applicable, in fire separated sections of the premises, should be kept to a minimum. Each heater brought into a room for use in an emergency should:

  1. be located so as not to affect the means of escape (eg it should be placed away from room exits and not in corridors or circulation spaces forming part of the means of escape) and should not be exposed to draughts;
  2. be placed in its allocated position with at least one metre clear space around it except that the heater may be placed adjacent to a wall provided the hot surface faces away from the wall and there are no curtains or other combustible materials within the metre space.

Special consideration may need to be given to the location of heaters in laboratories, art rooms, or workrooms where highly flammable materials may be used and where a safe location cannot be identified an LPG heater should not be used.

There should be clear instructions that when a suitable location has been identified the heater should not be moved without the authorisation of a competent person. It may be useful to provide a sketch for use by the fire brigade showing the locations of the LPG heaters in each building.

Toxic Risks and Ventilation Requirements

The use of LPG heaters has resulted in some complaints of nausea, headache and excessive humidity. There is also the possibility of fatigue, dizziness and, in extreme cases, unconsciousness and death from a build-up of carbon monoxide in poorly ventilated rooms.

All gas fired appliances produce as combustion products water vapour, carbon dioxide and, usually, trace concentrations of carbon monoxide. The amount of carbon monoxide produced depends upon the quality of the input air and on burner design and efficiency.

Atmosphere sensitive devices are designed to shut off the gas supply to an appliance before the carbon dioxide content of the surrounding atmosphere exceeds a given level.

However, they are not sensitive to carbon monoxide but their operation is such that they should prevent acute gassings and fatal accidents. It is essential that adequate ventilation is provided and maintained in rooms in which heaters are used.

Both high and low level ventilation is required and should never be blocked to prevent drafts. This may require windows to be kept open even in cold weather if fixed open vents are not available.

Operation and Maintenance

Many heaters have surfaces capable of causing burns. Employers should consider the means by which accidental contact with hot surfaces can be minimised and the appropriate precautions which they need to take. Suitable fire guards may be necessary.

Heaters should be lit and controlled only by a trained and authorised person. Each heater should be checked for leaks and damage before it is lit each morning and when turned off at the end of the day.

The check should include a visual examination to ensure that: the hose is not damaged or worn, that the cylinder and valves do not appear to be damaged or tampered with, that the connection between hose and cylinder is properly made and that the cylinder is not leaking.

At the end of the day it is most important to ensure that the valve is turned off and to check that the cylinder is not leaking. The cylinder should be changed only by a trained and authorised person.

Before connecting it is essential to check that the connections are compatible and correct for the equipment. Connections should be tightened firmly but should not be overtightened as this can lead to damage of threads.

Where spanners are used for tightening and undoing connections they should be of the correct size. The cylinder should be changed only in a well-ventilated place, preferably in the open air, but where it is not reasonably practicable to do so, all naked flames and other sources of ignition, eg cigarettes and any other heaters in the room should be extinguished.

Students should not be present during cylinder changing.

It is not the job of a teacher or lecturer to carry out any of the above tasks.

Emergency Procedures

All staff should have received instruction and training appropriate to their responsibility in the event of an emergency.

As part of the safe system of work each premise should have written procedures for dealing with a damaged appliance or cylinder, an escape of gas, or a fire. The procedure should include the steps which need to be taken should an incident occur.

Leakage without fire: If an appliance or cylinder is found to be leaking without the gas igniting, the action taken should include the following, providing, where appropriate, it is safe to do so.

  1. The main valve on the cylinder should be closed to cut off the gas supply.
  2. All possible sources of ignition should be extinguished.
  3. The room should be evacuated other than persons involved in the emergency procedures.
  4. The area should be ventilated.
  5. The appliance/cylinder should be removed to a well-ventilated place in the open air away from sources of ignition.
  6. Unauthorised approach to the appliance/cylinder should be prevented.
  7. If the leak persists the fire brigade should be called and informed that LPG is involved.

Leakage with fire: The gas from a leaking appliance/cylinder may catch alight. The action taken should include the following:

  1. Anyone who discovers a fire should sound the fire alarm.
  2. Persons not connected with the emergency procedures should be evacuated from the building.
  3. The fire brigade should be called and informed that an LPG cylinder is involved.
  4. The flame should be extinguished IF IT IS SAFE TO DO SO by turning off the value.
  5. If the flame from the leak is extinguished but vapour continues to escape, action should be taken as outlined above.
  6. If the flame cannot be extinguished, fire fighting should be left to the fire brigade and the building should be evacuated immediately.

Fire in the vicinity of an LPG heater: Action should include the following:

  1. The establishment’s fire and emergency procedures should be initiated.
  2. IF IT IS SAFE TO DO SO the gas supply should be shut off by closing the main value.
  3. IF IT IS SAFE TO DO SO the appliance/cylinder should be removed to a wellventilated place, in the open air away from sources of ignition.