In-cell fire fighting

In-cell fires are difficult to deal with, not only do you have a fire in a confined area, but also you have a potentially violent inmate who possibly started it to get the door opened. You are still faced with a fire that must be extinguished rapidly without someone being hurt in the process.

The standard method is to remove the inundation point in the door and direct a fire hose through it to try and put the fire out. This usually involves a lot of water, and is a haphazard process because it is impossible to see the fire in the cell due to smoke. The time to extinguish the fire is considerable, damage to the cell and those below is often caused and water can run out under the cell door into the landing. The occupant isn’t always saved from further injury and may decide to hinder the process.

To achieve this a lance is inserted through the inundation point and turned on. It has a misting nozzle that creates a wide plume of atomised water with a  6 metre throw and can be directed anywhere in the cell. The lance is angled to aid directional control. The fire is extinguished rapidly and uses less than 15 litres of water per minute.

Developed by Watermist Ltd & Fireworks Fire Protection in Norwich the system was first trialled in 1995 and is available in three forms. All use the same water lance delivery method, and what varies is the equipment for getting the water to the cell. The portable version is a wheeled unit that is stored in a locked cabinet on the landing. It has an integral 35ltr water tank which is enough for a 5 minute run time, it can also be refilled while in use. All that is required is a standard 13 amp plug socket to provide the power. When a fire is detected the unit is simply plugged in and wheeled to the cell door.

The modular unit, which is fitted into a wall cabinet with a 35 metre high pressure hose and integral pump unit. The method for extinguishing a fire is the same as the portable unit. There is also a fixed system where the pump unit is situated in the building plant room connected to wall mounted hose reel cabinets located around the prison.

Hydramist® products are protected by worldwide patents.

This method of fire extinguishing has impressed many fire brigades. It was developed in co-operation with the MoJ and the Building Research Establishment at Watford. To test the system BRE built a double sized mock up cell complete with cell door. A fire was started and allowed to establish for 5 minutes.  The ‘inundation point’ was removed from the door and a standard fire hose was introduced. The standard hose reel was found to have little or no effect on the fire. The temperature and toxic gas content rose to levels that would threaten life.

The test was repeated using a Hydramist® lance for a maximum of 5 minutes only. The cell door was then left open to simulate a ‘snatch’ rescue, the door was shut again and the cell left untouched for a further 5 minute period. After this time the fire had not reignited and the gas and smoke levels had not risen.  From time of inundation to the end of the test a life sustainable environment was achieved within the cell using this system.

At the point the water was introduced the cell maximum temperature was 700˚C. It fell almost immediately to 80˚C and eventually dropped to 10˚C. The equipment used less than 35 litres of water enabling the cell to be cleaned with a mop. Because the water ‘finds’ the fire it was under control in 2 minutes and out in only 5.

Monitoring equipment placed at 3 locations and 5 levels in the cell proved that the temperature and toxic gas levels dropped dramatically as soon as the atomised water was introduced and they did not rise again after inundation. Both stayed at levels that would support life.

Because the water droplets fill the air it’s difficult for the inmate to detrimentally affect the systems ability to extinguish the fire. The lance also has a device to provide a seal around the inundation point and to protect the operator’s fingers by preventing pull through.

In a recent episode a cell fire was tackled using a portable Hydramist® unit. 2 minutes after the lance was activated the inmate was asking for it to be turned off because he was cold. When the full 5 minutes use had elapsed the inmate was taken out of the cell, a couple of smouldering items and embers were removed and the inmate was returned to the cell, given paper towels and told to clean the cell floor by himself. The inmate was able to sleep in the cell that night. Keeping cells in use is a vital advantage with the present pressures on capacity.

For more information can you please contact Fireworks Fire Protection Ltd directly on 01953 861070 or visit their website www.fireworks-ltd.com.

Hydramist is a registered trade name.