Computer Room Fires
Is there a computer room in your response area? If so, have you toured the facility? Are you familiar with the special characteristics of computer rooms that affect firefighting strategy and tactics? How would you handle a fire alarm for the facility? Would your actions take into account the costliness of computer equipment and the loss of the computing function to the affected company?
Many companies rely on computers to conduct their business. Although the equipment is insured, a fire could render the computer equipment unusable and could bankrupt the company in a matter of days.
Pre-fire planning is your greatest asset in handling an incident involving a computer room. If you’re aware of a computer room in your response area, contact the company and explain your concern. Most likely, you’ll be vvelcorned, and a tour for you and your officers can be arranged. A tour for the whole fire department would probably not be well-received due to space and workload requirements.
Computer rooms —more commonly referred to as data centers—are usually centrally located within a building. If located on an outside wall, the room will have no windows but may have an emergency exit or loading doors so as not to advertise the location to possible intruders. In a multiple-story building, the data center may be located on any floor.
The entrance to the computer room itself is usually through card-key or combination-lock, vault-like metal doors, which may or may not be guarded by security personnel. Any windows will be wired glass. Forcible entry could result in costly damage; if possible, firefighters should rely on company employees to gain access to the room.
The computer room floor most likely will be raised about a foot, but it might be raised as much as three feet in the newer centers. The raised floor is used to run cables between equipment and acts as a plenum for the air conditioning. (The downdraft of conditioned air moves through the floor space and finds outlet through the flooring, thereby cooling the machines before reaching the ceiling and completing the HVAC circuit.)
The floor tiles are supported by screw-tvpe jacks usually bonded to the subfloor. The tiles can be aluminum or pressboard that’s framed and covered with carpet or linoleum. Care must be taken when removing these tiles. Given the weight load, removing a number of tiles in one area may result in a domino effect, with computer equipment sliding about. The tiles are removed with a device called a floor puller, usually located on a bracket on the wall of the room. Velcro is used for the carpet-type tiles, suction cups for the linoleum-type.
Most computer room fires start elsewhere in a building and spread to the computer room, but the room itself supplies a sizable fire load and many potential fire hazards: paper products, miles of current-laden cables (the current which feeds a computer room may be as high as 440V AC), air conditioning units, and dozens of electric motors, switches, and relays located throughout the room. Then, of course, there’s the greatest fire hazard of all… people!
People are fire hazards, it’s true, but they should be used to obtain a firefighting advantage whenever possible. An employee who is familiar with the computer room, for instance, may be able to supply valuable information to assist in the firefighting effort.
Suspended ceilings are characteristic of computer rooms. They contain a variety of utilities such as normal electrical wiring, HVAC systems, fire-suppression pipes, and water supply lines.
The data center contains a variety of computer and ancillary equipment. The cables connecting the equipment will most likely be under the raised floor. The equipment may or may not be connected to an emergency poweroff switch located at each exit or linked to breakers located in, near, or far from the room. Each unit will have breakers located on the outside or inside of the unit, or perhaps on a wall panel, for power-off. The power may or may not be powered off by a fire alarm or suppression-system activation. All computer rooms and computer equipment are different; only through pre-fire planning can you ascertain the particulars of the data center(s) in your jurisdiction.
The computer room may be equipped with sprinklers, a halon deluge system, or a combination of both. Contrary to popular belief, sprinklers can be used in a computer room as long as there’s an automatic electrical power-off upon alarm and the system is kept clean by flushing the water out of it at least twice a year. Clean water is not dangerous to computers as long as the system is powered off. Sprinklerequipped rooms should have drains in the subfloor.
Most computer rooms are equipped with smoke detectors arranged in a zoned svstem for fire detection. Singledetector activation sounds one type of alarm (which usually is an “investigatory” type of alarm that does not activate a halon dump, allowing a company official or employee to use discretion as to whether or not a fire emergency exists); detection by two or more zones sounds another type of alarm (which usually means that a distinct emergency exists and that a halon dump, possibly controlled by a delay timer set anywhere from instantaneous to two minutes, is imminent). Of course, there is the infamous “trouble” alarm which indicates that there’s something wrong somewhere in the system.
The sprinkler system may be wet or dry. Some companies may prefer the dry system to eliminate any possibility’ of leakage onto equipment. The heads may be fixed temperature-fusible link or on/off heads activated by a bimetal strip to control the flow. Halonequipped systems will be suited with abort stations located next to the exits, which, as a safety device, will abort the discharge during the delay period. This is important not only from the standpoint of human safety; Halon 1301, the fire-suppressant gas used in deluge systems—it spreads faster to a wider area than the other halons—is very expensive. A small system protecting a room about twice the width and length of a fire department pumper costs about $4,000 to recharge.
Halon 1301 is discharged as a colorless gas. During its discharge, it condenses water vapor in the air and becomes translucent, giving the impression that it’s light grey in color. While the manufacturer of Halon 1301 stresses the safety for human exposure to the gas, a maximum of a 10-minute exposure without SCBA is suggested. Should someone be exposed, he or she may show signs of respiratory distress and should be removed to fresh air as soon as possible and turned over to medical personnel for proper evaluation and treatment. Upon exposure to heat and/or flame, halon can generate small amounts of bromine gas, hydrogen fluoride, and hydrogen bromide. The normal concentration of halon in the room is 5% to 7% after discharge.
On a response to a computer room fire, the halon would probably have discharged before firefighter arrival, and SCBA use would be standard operating procedure. If you’re in a computer room at the time of discharge, you would hear, in addition to the alarm, a loud “whoosh” immediately before the discharge. Do not attempt to exit the room, as visibility will immediately diminish to almost zero. The danger in discharge of the halon is the force of the gas—it blows anything that’s loose all over the room, turning them into flying missiles. Drop to your hands and knees, and wait for the room to clear in a few minutes. As you exit, make sure that the door is closed behind you, since halon may not extinguish the fire immediately. It will take a few minutes for the halon to reach into the combustion process and chemically interrupt the fire.
Upon discharge, the room should remain sealed for at least 10 minutes, then the halon and smoke (if any) should be ventilated out of the build| ing. Since halon destroys the ozone layer around the Earth, it’s reasonable to speculate that the Environmental Protection Agency may issue other instructions in the future. For the time being, however, venting halon into the atmosphere is not illegal or controlled.
If there is a fire in the computer room, give the halon a chance to work. If your SOP calls for attack lines, place them just outside the doors to the room. Most likely, you won’t need them. There will be Halon 1211 hand extinguishers located throughout the room that can be used to douse any remaining embers.
If you make the decision to advance a handline into the room, ensure that the power has been turned off. The fire detection and/or the halon discharge may or may not power-off the equipment or the air conditioning units. Chemical extinguishers should not be used (since electronic boards are manufactured by etching with acid, and the powder used in chemical extinguishers is a base).
CO2 extinguishers are not quite as damaging as chemical; however, the extreme cold may damage some equipment. Remember though, that CO2 should never be used in conjunction with halon fire-suppression systems because it will displace oxygen. Halon plus CO2quals dead bodies.
In the overhaul phase of operations, do not attempt to return power to the room unless company management as. Covering the equipment with tarps is advisable unless the equipment is running due to ventilation requirements. On-site employees should be consulted. Some sites will have rolls of plastic available. Any equipment or documents removed from the building should be secured by the fire department, police department, or company representatives. Should you respond to an incident in which halon has been discharged, you should advise the company personnel that, until the system is recharged, portable fire extinguishers will be their only fire protection unless they have a dual halon system (which is rare) or a sprinkler system.
For more information and to borrow a VHS tape describing how halon is used, contact the DuPont Company. Ansul Fire Protection also has information available.
E.I. DuPont de Nemours & Co., Inc. C & P Department Barley Mill Plaza – PI 12214 Wilmington, DE 19898
ANSUL, Inc.
Marinette, WI 54143
