The LWF Blog
Fire Safety for Healthcare Premises – Compartmentation – Part 36August 20, 2018 1:54 pm
In LWF’s blog series for healthcare professionals, the aim is to give information on best practice of fire safety in hospitals and other healthcare premises. In part 35 of this series, we looked at how the openings in compartments must be protected via fire-stopping to avoid the spread of fire, smoke or hot gases through to other compartments. In part 36, we’ll discuss junctions of compartment walls with roofs and glazing in a compartment wall, both of which are possible areas of weakness if not fire-stopped adequately.
Junction of compartment walls with roofs
A compartment wall must be taken up to the underside of the roof covering or deck and fire-stopped to maintain the fire resistance of each element. In situations where there is an eaves cavity, the compartment wall should also be continued across.
As per Approved Document B, a zone of the roof which is 1.5 m wide on either side of the wall should have a covering designation AA, AB or AC on a substrate or deck of a material of limited combustibility. Further information on these designations can be obtained from Approved Document B, Appendix A, Paragraph 6 (PDF) which is on page 120 in a pdf reader.
HTM 05-02 notes that double-skinned insulted roof sheeting with a thermoplastic core should incorporate a band of material of limited combustibility at least 300 mm wide centred over the wall.
While the above description is one acceptable method, it is also possible to extend the compartment wall through the roof for a height of at least 375 mm above the top surface of the adjoining roof covering.
Glazing in a compartment wall
There would be little point in a compartment with a minimum fire resistance if any windows placed in that compartment were not also subject to the same period of fire resistance as the other elements in terms of integrity and insulation. BS EN 12600:2002 – Glass in building. Pendulum test. Impact test method and classification for flat glass gives reference to the requirement for any glazing used to have a permanent and legible mark which details the manufacturer, product name, fire-resistance rating and any requirement for impact safety performance. It should be noted that BS EN 12600 has partially, but not entirely replaced BS 6206:1981 – specification for impact performance requirements for flat safety glass and safety plastics for use in buildings.
In part 37 of this series, LWF will talk through sub-compartment walls in terms of fire resistance. In the meantime, if you have any questions about this blog, or wish to discuss your own project with one of our fire engineers, please contact us.
Lawrence Webster Forrest has been working with their clients for over 25 years to produce innovative and exciting building projects. If you would like further information on how LWF and fire strategies could assist you, please contact Peter Gyere on 020 8668 8663.
While care has been taken to ensure that information contained in LWF’s publications is true and correct at the time of publication, changes in circumstances after the time of publication may impact on the accuracy of this information.