FAQS on implementation of HSE recommendations on replacement of Halon fire systems

Please send any queries you have on the HSE document and the procedure you have to follow to anthony.fox @which.net. Questions, and replies, will be listed here. Please do not contact the HSE direct on the matter.

The following questions have now been passed to the HSE.

Query No.	Question	Answer
	GENERAL QUESTIONS
G1	What about Class 140 and 141 Pacer units now in preservation?  They have BCF/halon systems in place, similar to first generation railcars.  Can we assume that HSE will view these units in the same way?	The advice given previously relates to first generation multiple units / railcars. It is not considerd that these vehicles fall within this category.
G2	The HSE statement refers to first generation cars built from 1957 onwards.  Three preserved vehicles, 79900 Iris and Derby Lightweights 79018/79612 predate this, and they also have halon-based systems.  Can we assume that the statement also applies to these vehicles?	Yes.
G3	The EEC Directive requires that ALL systems (except those which have exemptions) using halon must be decommissioned and halon physically removed by 31/12/03.  Halon must be recovered in accordance with Article 16.  The latter does not include a date by which recovery must be completed.  Please advise.	No date is specified but disposal post removal should be sooner rather than later because of storage requirements in the interim.Further advice may be obtained from the Dti at www.dti.gov/access/ozone.htm or the Halon Users National Consortium at www.hunc.org and Brian Dale of HUNC on 01420-538855 or Ronnie Drugan at Kidde Graviner at www.kiddegraviner.com
G4	As passenger safety is not an issue, can  we assume that there are no restrictions on shunting and empty stock movements after halon bottles have been removed from vehicles but before superseding systems are in place?	Not seen as a problem providing the driver can evacuate his cab without putting himself at risk.
G5	Can a vehicle operate in passenger service when implementation of a superseding system is complete and as soon as the supporting documentation is lodged with the local HMI (as is implied in  the HSE letter)?  Or is a physical inspection by HMI required before passenger service can re-commence?	HSE is content with a letter to the local inspector for the railway concerned stating what work has been undertaken to a vehicle. The vehicle would then be inspected when the opportunity presented itself.
G6	A 2 litre AFFF extinguisher has a fire rating of 55B which means it will put out 2.2 square metres of burning fuel in a duration of 9 seconds.  2 litres of AFFF is equivalent to 5kg of halon 1211, the amount stored in existing fire bottles.  Do HSE accept that this 2 litre capacity is satisfactory for fixed or portable AFFF extinguishers mounted near each engine?	Advice has been taken by a fire specialist such that the efficiency of AFFF does not compare with Halon and that it would be more appropriate to consider four litres.
G7	An engine fire amidships may require passengers to detrain from both ends of a power car.  A ladder is available in the guard’s brake at one end of the vehicle, or if the vehicle has no guard’s brake then passengers can pass via the gangway to de-train from the adjacent coupled vehicle.  Are the built-in steps sufficient for use by passengers who de-train via the driver’s cab?	Providing there is always at least one ladder aboard and the steps are in good order then HSE is content with this proposition.
	QUESTIONS RELATING TO OPERATION WITHOUT AUTOMATIC  FIRE SUPPRESSION
W1	If hand-operated extinguishers adjacent to an engine are mounted permanently (as opposed to being stored inside the vehicle and mounted outside only when the vehicle is in service) what security arrangements are acceptable, consistent with speed of access in an emergency?  For example, can extinguishers be located inside special cabinets with carriage key locks, or inside battery boxes where use of automotive batteries creates spare space?	No problem is foreseen utilising redundant spaces within battery boxes or adding a suitable and secure cradle in which to place the extinguishers. The use of carraige keys to obtain quick access for emergency use is in order: (position a carraige key in a discreet location near to the cabinet as a back up).
	QUESTIONS RELATING TO MODIFICATION OF FIRE SUPPRESSION (OR COMPLETE) SYSTEM
R1	Proven systems are available (e.g. as used in road vehicles) which could replace existing fire detection and extinguishing systems in toto.  They would of course be interfaced with engine stop and alarm circuits.  How does HSE regard this alternative, given that operation is on private railways at 25 mph max.	This is not considered necessary.
R2	Items a). to g). in the HSE letter relate to systems where automatic fire suppression no longer exists.  Can we assume that none of these points will apply if a replacement system continues to employ fully automatic extinguishers?	Correct but it remains good practice to follow.
R3	What is the HSE view on powder-based alternatives to AFFF? (i.e. keep the same detection set-up but replace halon with powder, introducing appropriate new discharge pipework and nozzles if necessary).	Powder is good for electrical fires but AFFF performs far better on fuel fires
R4	Please confirm the HSE review process for replacement systems which incorporate automatic fire suppression.  Can a vehicle operate in passenger service prior to an HMI inspection?	Any proposal for such systems should be submitted to the local inspector who will forward to the appropriate specialist inspector.