Also Look At

Technical Information

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• General technical information
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• Plan safety & quality

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• Why penetration seals demand more attention

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• Different types of penetration seals
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• Combustible penetrations
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• Loadbearing seals

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• Movement of penetrations & services
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• Specifications & installation of penetration seals

Combustible penetrations

Electrical and communication cables or cable bundles, plastic pipes and some insulation products used for pipe or ductwork lagging will burn. These are all potential points of failure. Small single cables do not present much of a problem as they tend to extinguish themselves at their junction with the penetration seal. A large number of cables (or cable bundles) will, however, cause some difficulties. Although cables should be protected each side of the seal — in effect, creating an exclusion zone — extra care must be taken to ensure that cables do not overheat and degrade their designed electrical capacity.

Plastic pipes are less of a worry, as an intumescent collar or wrap, can be fitted, usually quite easily, around the pipe.

These collars or wraps will crush and close the pipe in the event of a fire and will prevent flames and smoke passing through it.

If there is a gap between the pipe and pipe sleeve, it is likely that an additional "cold smoke" seal will be required as the collar will not operate until the temperature is sufficiently high enough to activate the intumescent seal. In fact, such a "cold smoke" seal is almost always required and is achieved simply by installing the appropriate quality fire resistant sealant.

It is important to note that different types of plastic behave in very different ways to actual fire conditions, as do different wall thicknesses of the same plastic type. Extreme care should therefore be taken to ensure that the chosen pipe collar or wrap is fully tested to demonstrate it is capable of providing the requisite performance under actual fire conditions for the type of plastic, the pipe thickness and pipe diameter in use.

It is also important to note clearly that it does not follow that all plastics, of all similar dimensions and thicknesses, behave in a similar manner. On the contrary, there can be clear and noticeable differences in the performance between, for example, 50mm and 150mm diameter pipes of the same plastic type and thickness. Similarly, there can be marked differences between two 110mm diameter pipes with 2mm and 10mm thickness of the same plastic type.