Mitigate risks to your data and equipment
Most electronic equipment is not highly combustible. There are plastics in the circuit boards, some of the casings, and other components, but the total energy of combustion is usually very small compared to typical storage or office occupancies. Fires originating in electronic equipment usually develop slowly and the heat release rate is low. However, even small fires can result in huge interruptions since facilities rely so heavily on this equipment. Consequently, an effective loss control program must minimize the probability of fire and maximize loss control equipment effectiveness in EDP rooms.
Organizations should have a structured approach in place to manage their exposures. TÜV SÜD Global Risk Consultants (GRC) recommends several steps to help minimize potential physical damage from a fire in EDP equipment:
STEP ONE: MANAGING EDP EQUIPMENT ROOMS
Most “catastrophic” losses in EDP rooms involve extraneous combustible materials or equipment filled with combustible liquids. These can be avoided with proper housekeeping and equipment arrangement. This includes cable management, electrical maintenance and self-inspections.
STEP TWO: PROVIDING GOOD FIRE PROTECTION
Electronic equipment fires typically grow slowly (20 minutes or more) after components begin overheating. Highly Sensitive Smoke Detection (HSSD) senses these fires before there are open flames and should be in all significant EDP areas. Use of HSSD maximizes the response window and allows time to investigate and isolate or de-energize equipment before operations are affected or significant hazards are generated.
Alerted by a smoke alarm, an effective and well-trained response team will:
Automatic suppression systems and energy efficiency schemes are also commonly used in areas housing EDP equipment. Most clean agent systems work primarily by chemically interfering with the combustion process or by reducing oxygen concentration. The larger the room, the less practical it becomes due to the high cost of extinguishing agent. There is also the need to maintain the integrity of the “envelope” of the room so the agent will remain at an effective concentration. Controlling, detecting, and repairing penetrations in the envelope become more of a problem as the size of the room increases. All of this increases installation, testing, and maintenance costs and is why most large data centers do not use clean agents.
Clean agent systems usually have a one-shot agent supply. If the system discharges and the fire does not go out or rekindles because power has been left on, there is no more agent to control the fire. This limits effectiveness. Concerns about human toxicity of some agents can also hinder effectiveness. Once the system has discharged, people do not normally re-enter the area without proper protective equipment or until the agent has been evacuated.
Sprinkler systems are usually needed to meet fire and building codes and are valuable as catastrophic property protection. If a fire in an electronic equipment area gets so large that sprinkler heads open, the problems are beyond a typical electronics fire and severe damage has already occurred. Therefore, sprinklers are not considered to be a primary loss minimization system. As computing power continues to increase, the amount of space required for EDP to support a particular operation decreases. Installing sprinklers provides flexibility for future use of space no longer needed for EDP, minimizing long term costs.
Accidental water discharge from sprinkler systems is a common concern. Sprinklers are extremely reliable and leaks are rare. Several studies indicate the probability of a leak is less than one in a million heads per year. It is even less in the benign environment of a data center- where vibration and risk of impact damage are minimal and temperature and humidity are consistent. Chilled or hot water pipes routed through or near an EDP area are a more likely source of leaks than sprinkler leakage, double interlocked pre-action systems can be installed. These systems require a sprinkler head to fuse in addition to fire detection actuation before water enters the piping. They are expensive to install and require more maintenance than a wet pipe system so they should be used only in the most critical areas.
These systems are no substitute for effective personnel response. Delayed response resulting in system discharge before personnel arrive on the scene will likely result in more downtime than if prompt response had identified the source of smoke before agent discharge. This is especially true if power is not shut off to equipment on agent discharge. Therefore, the importance of good, early warning fire detection and quick, effective response cannot be overemphasized. Where effective response cannot be guaranteed, e.g., remote installations, clean agent extinguishing systems may be the appropriate protection scheme (just be sure to power down when the agent is released.
Most large data centers are now using hot aisle or cold aisle containment to improve cooling and reduce energy usage. Both systems are designed to prevent mixing of the cooling air with warm air before it passes by the equipment. In cold aisle containment the cold air typically travels from the computer room air handler (CRAH) through an under floor supply plenum, passes through the floor panels into the cold aisle, through the equipment to the hot aisle and rest of room, and back to the CRAH. With hot aisle containment the cooled air leaves the CRAH, is discharged into the room, passes through the equipment and into the hot aisle. The air is then channelled into an overhead return plenum to be returned to the CRAH or is exhausted through a chimney.
Both types of containment require the IT equipment be physically separated from the room by a containment barrier. Barriers used for containment should be noncombustible; metal or tempered glass panels where practical. Metal panels cannot be used where light transmission is required and tempered glass is heavy and expensive. Therefore, translucent plastics are often used as containment barriers. TÜV SÜD GRC recommends they be rigid, Class A plastics with a Smoke Developed Index (SDI) of 120 or less per ASTM E84. Most polycarbonates meet these standards. Flexible plastics should be avoided as they require less ignition energy than rigid plastics. Class A plastics with a high SDI (up to 450 still meets Class A requirements) generate more contaminating smoke when they should burn and should be avoided.
Smoke detectors/air sampling points at the return air grilles of the CRAHs is the standard approach for rooms without aisle containment or with cold aisle containment. Each CRAH re-circulates air in a specific zone so smoke detected entering a particular CRAH identifies the area with the problem. With hot aisle containment, cooling air passes through the equipment racks and into the hot aisle. Placing detectors in each hot aisle uses this airflow pattern to create zone detection (one zone per hot aisle). Other arrangements using aspirating detectors may be appropriate, depending on air circulation geometry.
Fire Protection for Electronic Data Processing Rooms is only one aspect of mitigating fire and explosion-related risks. Now, more than ever, organizations have a strong need to adeptly manage their exposure to fire and explosion risks. This is a result of many reasons, including increased regulatory activity, higher levels of public scrutiny, greater demands for aggressive environmental liability management, stricter insurance requirements, and new technological advances for processing and warehousing.
TÜV SÜD Global Risk Consultants (GRC) engineers have pioneered advances in fire protection by applying their in-depth expertise to develop new methods to address today’s escalating concerns. As an industry leader, we have successfully solved fire protection issues to ensure the health and welfare of our clients’ businesses around the world, something we have done for decades.
TÜV SÜD GRC is dedicated to providing sound, cost-effective Fire Protection Engineering to address today’s newest challenges in fire and explosion property loss prevention coupled with increased competitive demands.
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