In a data centre the big loss rarely comes from a big fire. Smoke from a small fire in a single cabinet is spread across the whole hall by the cooling air and contaminates thousands of devices with corrosive residue; a pipe failure floods the raised floor void; a UPS battery goes into thermal runaway and causes an outage lasting hours. FM Global DS 5-32 Data Centers and Related Facilities treats these risks together, in terms of the building, the protection systems and business continuity.
Scope
The data sheet covers data halls, computer and telecommunications rooms and the support areas that serve them: UPS and battery rooms, generators and fuel systems, cooling plant, electrical distribution rooms and equipment staging areas. The drivers of loss in a data centre can be summarised as follows:
| Loss driver | Typical source | Main measure |
|---|---|---|
| Fire | Cables, server plastics, UPS, batteries | Sprinklers plus early detection |
| Smoke contamination | Combustion products of small fires | Very early smoke detection and fast response |
| Water damage | Cooling pipe leaks, roof leaks | Leak detection, pipe routing, drainage |
| Loss of cooling | Chiller/CRAH failure, power outage | Redundancy, monitoring |
| Loss of power | Utility, UPS or generator failure | Redundancy, maintenance, fuel management |
Key Loss-Prevention Principles
1. Construction and separation
The data hall should be of noncombustible construction and separated from higher-risk support areas by fire-resistant elements. Battery rooms, generators, fuel stores and staging areas holding cardboard and packaging are separated so they cannot carry fire and smoke into the hall. Firestopping cable and pipe penetrations is needed both for fire separation and, where gaseous suppression is used, for enclosure integrity.
2. Sprinkler protection
In the FM approach all areas, data halls included, are protected by automatic sprinklers. Where accidental discharge is a concern, pre-action systems are usually chosen; and because sprinkler heads open individually by heat, water is delivered only where the fire is. A common misconception is that sprinklers will soak the whole hall; in reality the affected area is limited to the immediate vicinity of the fire.
3. Hot and cold aisle containment
Aisle containment installed for energy efficiency can stop water from ceiling sprinklers reaching the racks. The solution is either sprinklers inside the containment or approved containment panels that drop or shrink when heated. Containment, cable trays and busbars are also checked against sprinkler obstruction rules.
4. Very early smoke detection
High airflows in data halls dilute smoke quickly, and point detectors can respond late. Very early warning systems such as aspirating smoke detection pick up a fire while it is still at the overheating or smouldering stage, giving staff time to shut down the affected equipment and stop smoke spreading. Detection should also be considered below the raised floor, above the ceiling and in return air paths.
5. Gaseous suppression as an added layer
Clean agent systems can be used as supplementary protection in halls critical to continuity. For FM, gas does not replace sprinklers; enclosure integrity, interlocks and hold time must be achieved in line with DS 4-9.
6. Power and cooling shutdown strategy
De-energising the affected equipment once a fire is confirmed stops a fire inside the equipment from continuing and makes extinguishment easier. How cooling behaves — balancing not spreading smoke against not diluting a gaseous agent — must be clearly defined in the cause-and-effect matrix. This is designed with the operations team, with outage scenarios in mind.
7. Lithium-ion UPS batteries
Lithium-ion batteries are now common in UPS systems. Because of thermal runaway, flammable gas release and re-ignition, they should be in separate fire-resistant rooms with the battery management system monitored, and protection should be assessed together with FM's battery-related data sheets.
8. Water damage and housekeeping
Cooling pipework through the data hall is avoided where possible; where it must pass, leak detection and drainage are provided. Cardboard, packaging and spares are not stored in the hall; new equipment is unpacked in the staging room.
How It Differs from NFPA 75 and EN 50600
NFPA 75 (protection of information technology equipment) and NFPA 76 (telecommunications facilities) give rules on construction, detection, suppression and power disconnection; NFPA 75 also relies on sprinkler protection for IT areas in sprinklered buildings. In Europe the EN 50600 series describes data centre facilities and infrastructure as a whole, with fire and security systems covered in the relevant part. The Uptime Institute Tier classification defines redundancy, not fire protection.
The FM difference is that it does not treat sprinklers as optional and sees loss not only as fire damage but as the sum of smoke contamination, water damage and business interruption. Early detection, separation and redundancy therefore carry as much weight as the sprinklers themselves.
Field observation: aisle containment and cable trays added after commissioning are the most frequent cause of sprinkler obstruction. Every new containment project should be reviewed against the sprinkler layout.
Practical Checklist
- The data hall is separated from battery, generator and staging areas by fire-resistant construction.
- All areas are sprinklered; pre-action has been considered for the halls.
- Aisle containment and cable trays do not obstruct sprinkler discharge.
- Very early smoke detection covers the hall, floor void and ceiling void.
- Where gas is used, enclosure integrity and interlocks are verified to DS 4-9.
- The power and cooling shutdown strategy is defined in the cause-and-effect matrix.
- Lithium-ion batteries are in a separate room and the BMS is monitored.
- No combustible storage in the hall; packaging is opened in the staging room.
- Water leak detection and drainage are fitted at critical points.
- The disaster recovery and business continuity plan is current.
Frequently Asked Questions
Won't sprinklers damage the equipment?
Sprinklers open only where the fire is. The damage from smoke and an uncontrolled fire is far greater than local water damage. Pre-action systems address the risk of accidental discharge.
If there is a gas system, are sprinklers still needed?
In the FM approach, yes. Gas discharges once and may not permanently extinguish a deep-seated fire; sprinklers are the final safeguard.
Why is aspirating smoke detection recommended?
In high-airflow halls it detects smoke at very low concentrations. Intervening before the fire grows limits both fire damage and smoke contamination.
How does hot aisle containment affect sprinklers?
The containment roof blocks water from ceiling sprinklers. Sprinklers are placed inside the containment, or approved panels that drop when heated are used.
Does the Tier rating cover fire protection?
No. Tier classification defines power and cooling redundancy. Fire protection is designed separately to references such as the FM data sheet, NFPA 75 or EN 50600.
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Download MEP Calc on the App StoreFM Global Property Loss Prevention Data Sheet 5-32, Data Centers and Related Facilities; FM Global DS 4-9; NFPA 75; NFPA 76; EN 50600 series. This page is a summary in our own words, not the data sheet text. Download and design to the current revision from fmglobal.com.