Fires are not uncommon in prisons with the majority being cell fires, often intentionally set. Ministry of Justice figures show that in 2011 there were 950 fire incidents in prisons.

Noting that the majority of the fires are in cells, the focus on fire safety in prisons is based around fighting the fire in the cell and preventing it from spreading from there. The issues with cell fires include the reason why they were started in the first place.  For example it could be a suicide attempt; an attack on someone else or their property; or an attempt to get attention. Prisoners will often barricade the door to their cell or threaten prison officers, making it difficult to enter the cell to fight the fire.

This means fire safety in prisons is a different task to fire safety in premises open to the general public. The most obvious difference being means of escape; you can’t allow prisoners access to the front car park of a prison! Means of escape has to be carefully planned to ensure the safety of those inside the prison and move them away from the fire without compromising the security of the prison.

Added to this is that firefighting is generally conducted in-house, Fire & Rescue Services only attend about 25% of fires in prisons.

What are the sources of fire? Well prisoners are allowed to have smoking materials in their cells. However, as far as possible items of furniture, bedding and clothing are made of fire retardant materials, although this does not extend to the prisoners' clothing and private effects which may include some electrical equipment. So sources of fire and ignition are difficult to control. Added to this the danger of entering cells to fight fires has to be factored in. For example, prison officers who attend cell fire incidents should be equipped with personal protective equipment. This can be either Short Duration Breathing Apparatus (SDBA) or a specially designed smoke hood known as Cell Snatch Rescue Equipment (CSRE). CSRE is effective for protecting officers from the effects of smoke while they are inundating a cell through the inundation point. They also allow a snatch rescue of a cell occupant but are not breathing apparatus suitable for full scale firefighting activities. In most establishments SDBA has been replaced by CSRE.

How do you fight a fire in a cell? Options include use of hose reels where the water can be put into the cell via the view port and fixed water based suppression, i.e. sprinklers or watermist allowing suppression without having to enter the cell. The problem here is obvious; tampering with the sprinkler head/watermist nozzles by inmates. Then there is access for maintenance; you can’t just show up and fix a faulty head. Any system has to be robust and require minimal maintenance.

Watermist has particular advantage in this area with the amount of water required, piping sizes and protected nozzles. Watermist can also be used in the hose application referred to earlier.

BRE was commissioned to carry out fire tests to evaluate various suppression methods and the results showed that both fixed and mobile watermist systems can provide an effective means of suppressing cell fires and maintain tenable fire conditions for both the prisoners in the cells and the prison staff providing rescue. The work was commissioned by the Ministry of Justice and based on the results they concluded that fixed watermist systems in cells would be their preferred choice and mobile mist systems introducing watermist via the inundation point in the cell door would be used where retrofit was not possible.

Fire detection in prisons is equally problematic for the same reasons as fire suppression. As well as prisoners tampering with detectors and alarms there are issues with maintenance as servicing in accordance with BS 5839-1 would require an annual test of the detectors, which is a bit more difficult in a prison. Whilst conventional detection can be used, aspirating detection offers benefits. The sample point being a very small hole - there is nothing to get a grip of. Sample pipes can be fitted in existing ductwork or, in some newer facilities with prefabricated cells, built in and fitted off site. Another advantages of aspirating systems is they can have several sensitivities each linked to a different signal outputs. At the highest sensitivity, local staff could receive a warning of a potential fire and investigate long before smoke levels reach the level of a normal point type detector. This could allow earlier intervention whilst minimising the potential for false alarms. Lower sensitivities could be linked directly to the general fire alarm.

Ultimately there are a number of things to be considered with regard to fire safety in prisons but the key is to consider a holistic approach covering all aspects of fire protection and detection and to ensure a rigorous fire risk assessment is completed for each premise.

Robert Thilthorpe, Technical Manager, FIA