Fire protection of computer and telecom rooms

There are two types of fire that can occur in a computer or telecom room, a smouldering fire and a flaming fire.

The smouldering fire occurs when an plastic coated electronic component or cable overheats. The smoke produced by the smouldering plastic can quickly become a danger to people, and provide serious and widespread damage to electronic circuits throughout the space*.

The flaming fire is produced when the overheated component is left unchecked. A flaming fire can then start which can quickly spread and present a danger to nearby equipment and even the building itself.

The primary fire protection goal may therefore be to ensure business continuity by rapidly extinguishing a smouldering fire and extracting and 'scrubbing' the smoke. Alternatively, the primary goal may be to protect the building and contents from a full-scale fire.

State of the art

Business continuity risk in computer & telecoms rooms has traditionally been minimised by use of very fast smoke detection connected to a gaseous extinguishing system. But these systems do not address the real problem, which is smoke, and they are generally not effective unless the space remains sufficiently gas-tight. In addition a gaseous extinguishing system may worsen the smoke problem by distributing dust and corrosive smoke particles throughout the space. (The new halocarbon alternative gases will increase this problem if the extinguishing fails because at elevated temperatures the gas itself decomposes into toxic and corrosive by-products.)

Building and contents protection has traditionally been achieved out by conventional pre-action sprinkler systems. These provide protection for the building itself but pipework and infrastructure can be large, and in case of discharge, water damage can be considerable.

Professionally engineered water mist suppression systems can provide a more effective solution for computer & telecom rooms which do not rely on enclosure integrity and are safe for people, equipment and the environment.

HI-FOG solution - features and benefits

Marioff has developed a range of HI-FOG water mist fire protection solutions for a wide variety of applications. The company has developed specialist solutions for both fire protection goals in computer & telecoms rooms.

The 'business continuity risk' is addressed by HI-FOG total flooding and smoke scrubbing systems activated by very fast detection. In the HI-FOG total flooding system ultra-fine mist / air mixture is discharged into the whole space for a period of ten minutes, sufficient to extinguish a smouldering fire.

The HI-FOG smoke scrubbing system, normally used in sub-floor spaces, extinguishes a smouldering fire and cleans or 'scrubs' the smoke from the air preventing costly contamination and damage to electronic circuits.

The 'buildings & contents risk' is covered by a HI-FOG sprinkler system approved by FM or VdS. These systems are particularly suitable for larger spaces since mist discharge is normally limited to a small area. Water discharge is less than 10% that of conventional sprinklers, so the risk of water damage is considerably reduced. Mist is only discharged in the part of the space where there is a fire, and nearby equipment is protected by radiant heat blocking.

For either approach, an accidental discharge poses no danger to equipment or people. The systems will operate effectively even if the door is open, allowing people to safely evacuate or enter the space.

HI-FOG Systems Details

A HI-FOG smoke scrubbing system consisting of nozzles, piping, a self-contained water and nitrogen cylinder unit, as well as smoke scrubbing pipework with water drains.

On activation, a specialised nozzle, installed inside the smoke scrubbing pipework, releases water spray at high velocity, creating a strong venturi effect. Smoke is drawn into the scrubbing pipework through a series of suction holes and is trapped with most of the discharged water in dedicated drains. The cleaned air, the finest fraction of the generated water mist as well as the nitrogen used as the atomizing medium return to the sub-floor through another series of discharge holes in the pipes. For total flooding systems, discharge nozzles are installed in a uniform grid at ceiling level.

HI-FOG pre-action sprinkler systems are powered by a GPU (Gas Pump Unit) which does not rely on any external power for operation. The pump can be driven by a number of standard nitrogen cylinders for the protection time required by the approval authorities.



Smoke scrubbing pipework. This consists of two horseshoe shaped tubes with special HI-FOG spray heads located inside each tube section. On activation these discharge water mist in opposite directions. The water is collected for later retrieval. Only a small amount of water, delivered in the form of fog or small droplets, reaches the protected space