PU Foam in Fire Stopping

Polyurethane foam, also known as "PU" foam, is a compressed liquid compound which when released into the atmosphere, expands rapidly and starts to form a solid - a process known as curing.

For a number of years, it's versatility has been greatly beneficial for many industries due to the ease of application, the building trade included.

Whereas some forms of the chemical product were known to be flammable, the introduction of a fire retardant formula seemed to rule out any downsides of the product.

Nowadays it would be difficult to find a construction site where it's not being used somewhere in the build.

However, like all products, it has its limitations. Unfortunately though, because of the fire-retardant properties many of the products now claim, it can often be found used as a solution to a range of fire stopping matters. Whereas in reality, its uses are in fact rather limited.

The reason being, often when testing, supporting evidence states that the foam has been tested as part of a system, usually in combination with a backing material such as mineral fibre. Subsequently, the performance of the foam alone cannot be guaranteed.

Also, the majority of foams are not meant to be used in gaps wider than 30mm. Hence the primary use of the foams is to fill voids around lintels, window casements and doorframes. All of which are perfectly good applications.

What is not a permissible application of the product is when it is used to fire stop service penetrations and large voids in fire-resisting construction. Too frequently now PU foam can be seen in an array of scenarios unsuitable for the design of the product, potentially compromising compartments within the building.

Incorrectly used to fire stop service tray penetration.

Correct Application of PU foam.

That's why we always recommend using a passive fire protection specialist when undertaking fire stopping works. They will have knowledge of the different products available, as well as the materials applications and limitations.

This subject reiterates the need for proper due diligence in regards to the use and approval of contractors within the property and construction industry. Contractors with appropriate training would understand the potential danger of using the incorrect material poses.

If you have concerns regarding the fire stopping in a building or are seeking clarification in relation to passive fire protection measures, please feel free to request further information on our "Compartmentation & Fire stopping Survey" or alternatively, see our website for further details as to how we can help.

Thank you for reading.

Sincerely

Athena FC Team