A fire in a cell is a very damaging and dangerous event. There is a potentially dangerous and probably very scared human being in a small locked room that is filling with smoke and getting hotter by the second. Putting the fire out used to be a matter of inserting a fire hose through an inundation point in the cell door. This has its drawbacks as the cell will be full of smoke and the inmate may be unconscious on the floor.  So they could asphyxiate or drown by the time enough water has been introduced to extinguish the blaze.

Another system exists that uses a fine mist of water to extinguish the blaze, its manufacturers claim it also has many other advantages over the conventional hose reels in that it reduces temperature and removes smoke without causing water damage. I spoke to Derek Killaspy about the claims he has made for his companies equipment.
Derek claims that the Watermist system protect assets, is environmentally better, prevents re-ignition, is safer for personnel, is easier to install and uses less water. These are bold claims and as this equipment is currently being installed in prisons I asked him to justify them!

CR    the Custodial Review
DK    Derek Killaspy

CR    You claim that the Hydramist system is fast and effective, what are you comparing it with when you say this?
DK    The comparison is with conventional hose reel systems, gas systems and foam systems! My statement is backed up by a report completed by The Building Research Establishment. BRE carried out comprehensive research in order to compile a report for the Ministry of Justice. BRE built a concrete block cell, installed safer cell furniture and personal belongings usually found in a typical cell, and then set fire to it. They then compared the extinguishing properties of different systems including conventional hose reel system and the Hydramist system. In a like for like test the misting system was found to be the quickest to extinguish the fire. The temperature at the fire front was reduced within seconds of the unit being activated. In addition it almost completely removed the smoke from the cell, something the hose reel did not even affect. The ability of the hose reel to extinguish the fire when it was not right in front of the inundation point was also poor compared to the misting unit. If the fire was in the toilet or basin where it is almost impossible to play the water directly on to then it could not do the job, the Hydramist equipment tackled these sorts of fires effectively wherever they were in the cell.

CR    You claim your system will prevent re-ignition. Don’t all systems do that?
DK    No, in the same BRE tests they allowed the in cell fire to burn for 5 minutes, then they had a 5 minute inundation, then a 2 minute interval while the door was opened to simulate a snatch rescue, then the door was closed and the cell observed for 5 minutes during which time the fire was not supposed to restart. The hose reel system failed this test predominately as it could not extinguish a fire completely unless it was on the floor by the door. If the fire was in the sink or on the bed where the hose reel jet could not play directly on it then the flammable material was not fully extinguished.

CR    You say it’s safer for personnel. If both systems operate by water being pumped through the inundation point then how can one be safer than the other?
DK    If an inmate is unconscious on the cell floor then it is possible for them to drown in a half inch of water. Our system uses less than 20 litres of water in a typical cycle. That amount of water does not collect to a significant amount on the floor. In addition a hose reel is quite a powerful jet; injury can result from being struck by it. The Hydramist system uses high pressure, but the pressure is used to create fine water mist at the nozzle, so the droplets come out very quickly, but they have very low mass and so do not injure on contact.