What is meant by a mixed service or multiservice penetration seal? Passive Fire Protection terminology

A mixed or multiservice penetration seal is where more than one of the same or different type of services penetrate the one aperture. For instance, a letterbox aperture above a flat entrance door containing a sprinkler pipe, cable tray, hot and cold water feeds and a plastic ventilation duct.

Multiservice penetration seals typically require a Fire Batt or Fire Protection Compound to complete the larger oversized aperture. Services are then sealed with additional fire stop seals that are fitted within, or to, the overall seal.

In accordance with BSEN1366-3, the fire resistance test standard, there must be a minimum of 100mm between penetration seals unless tested otherwise.

Whilst multiple services can penetrate the fire batt seal, the spacing requirements between the individual seals within the overall seal must be observed.

Therefore, spacing requirements could vary between different service types and may require 100mm between the seals. This is unless they are tested at less, which could be 50mm or even 0mm between services of the same type.

There is also a need to allow for space between the seals and the edge of the apertures. It is important to understand that the spacing requirement is between the service seals and not between the services themselves, so the seal size needs to be considered.

For more details, contact Quelfire technical at technical@quelfire.co.uk

Craig Wells

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