External LPG Fuelled Live Fire Training Rigs (Simulators)
1. A number of recent HSE inspections of LPG-fuelled simulators used to train firefighters identified concerns about lighting and the absence of flame failure arrangements. This advice has been prepared by HSE in the absence of any existing and specific industry standard.
What are these concerns?
2. On some existing rigs there is the potential for LPG to be introduced at the full burner flow rate without the burners being lit, or for there to be a delay in lighting the burners. Using fire simulators without flame failure protection presents a foreseeable risk of an LPG cloud being created, and the ignition of such a cloud could result in a large fireball and/or explosion.
Are there suitable standards for flame failure equipment?
3. There are no British or EN Standards relating specifically to the construction and use of these rigs. However, there are a number of other documents which suggest an appropriate standard of control for simulators.
4. Fire Service Manual Volume 4 'Fire Service Training' provides guidance in the safe and effective delivery of compartment fire behaviour training. This training can be delivered using a gas fuelled system. The external LPG fuelled fire training rigs are similar, and therefore this guidance provides a useful basis for determining the level of control which needs to be applied.
5. There are technical standards that are relevant to any gas installation, one in particular being BS EN 746-2 (Industrial Thermoprocessing Equipment). This includes the requirement for an automatic burner control system if the burner has a rated heat input of greater than 70kW (Section 22.214.171.124). Such an automatic control system should include a device for detecting the presence of a flame, and the system should shut down safely if a flame is not detected. The Standard states that thermo-electric flame supervision devices are not acceptable for burners with capacities above 70kW. For liquid-fuelled systems, section 126.96.36.199.5 also states that flame failure either during start-up or operation should result in the burner going to lock out mode (ie safe shutdown, requiring manual reset to restart).
6. The German standard DIN 14097 'Firefighting Training Facilities – part 2: Gas fuelled simulation devices' requires controls to prevent build-up of a flammable cloud and its immediate re-ignition, or gas shut-off if the flame is extinguished. Whilst a DIN standard does not directly apply in GB, it does indicate that it is practicable to comply with EN 746 for this class of equipment.
Does this guidance cover all eventualities?
7. No. The HSE inspections and subsequent discussions with other users indicated that there are numerous designs and ages of simulators in existence, and differences in their level of usage. The advice contained above provides a default solution to the dangers arising from LPG being introduced at the full burner flow rate without the burners being lit, or from a delay in lighting the burners.
8. If these default solutions do not seem suitable for any given installation, or if the design and use of the equipment gives rise to different risks, then it is entirely appropriate to assess the risks afresh from first principles based on a complete hazard identification study (typically HAZOP). This will ensure that the safeguards applied to a given training simulator will be proportionate to the assessed risk, and will provide an adequate level of control of that risk.
And remember the need for appropriate supervision and maintenance.
9. It is important that the use of the rig is properly supervised by a competent person to ensure that the supply of LPG can be turned off promptly when necessary, and that the rig is properly maintained.