T 3.85 Impairment of fire protection compartmentalisations

Numerous cables and lines are routed through buildings housing IT operations. Fresh and waste water pipes, heating pipes, power supply cables, and data transmission lines are examples of such pipes and cables. It is impossible to prevent such pipe and cable trays from crossing ceilings and fire protection walls. When suitable fire compartmentalisation is not installed at such locations (refer to S 1.9 Fire sealing of trays), fire and smoke can spread uncontrollably through such locations under some circumstances.

It is usually necessary once the building is in use to work on such trays or install new trays to perform repairs or to create space for additional cables and lines required.

When performing such work, some or all of the fire seals may need to be removed. Extra cables also change the fire load of a cable tray. The result is that the function of fire protection constructions may be significantly impaired while such work is being performed and afterwards as well.

Unfortunately, experience has shown that the persons entrusted to do this type of work (the planning, execution, and approval of the work) often misjudge the consequences of their actions for the fire protection, and act accordingly:

• Alternative measures to compensate for the fire protection removed are neither planned nor implemented.
• Damaged fire seals are not repaired immediately or not repaired properly.
• Fire protection measures are not adapted to the new situation.

The result of these human errors is a higher risk of ignition of a fire and a higher risk of spreading smoke and fire. If essential corridors or escape and rescue routes are affected, then not only the IT systems are endangered, but the health and welfare of personnel is also at risk. This can result in serious consequences in terms of liability.

Example:

• In a multistory office building, various networks were routed in a single, common cable ladder from the basement all the way up to the top floor. All holes through floors were designed to have an ample reserve, but the holes were not sealed again after the cables were laid. Large amounts of paper and fabric were stored in the basement near the starting end of the cable ladder. The upright part of the cable ladder extending above this would have acted as a chimney if there were to be a fire. Smoke and flames would have spread quickly to all other floors in the building.