Compartmentation is the fundamental principle that contains fire within defined boundaries, limiting its spread and providing time for evacuation and firefighting. In residential tower blocks — particularly those built during the post-war construction boom — compartmentation deficiencies are among the most common and most serious fire safety findings we encounter.
These deficiencies are not always the result of poor original construction. Many arise from decades of ad hoc maintenance, service installations, and partial refurbishments carried out without adequate understanding of the fire compartmentation they were compromising.
Service Penetrations Through Compartment Walls and Floors
The single most common compartmentation deficiency in post-war residential towers is inadequate fire stopping at service penetrations. Every pipe, cable, duct, or conduit that passes through a compartment wall or compartment floor creates a potential pathway for fire and smoke to breach the compartment boundary.
In our experience, the most problematic areas are service risers — vertical shafts carrying water, gas, electrical, and telecommunications services between floors. Over decades of service upgrades, seals have been repeatedly broken through and inadequately reinstated.
Compartment Wall Integrity Above Suspended Ceilings
A compartment wall must maintain its fire resistance for its full height. Where suspended ceilings have been installed, a common deficiency is the failure to extend the compartment wall above the suspended ceiling to meet the structural soffit.
Cavity Barriers in External Wall Construction
Post-war residential towers that have undergone overcladding or external wall insulation works are particularly vulnerable to missing or inadequate cavity barriers. Cavity barriers are required at compartment lines, around openings, and at defined maximum intervals within the external wall cavity.
Our Approach
Apex Fire Engineering conducts compartmentation surveys that combine desktop review of available construction records with systematic intrusive inspection of compartment boundaries. We identify deficiencies, categorise them by severity, and provide prioritised remediation recommendations supported by annotated floor plans and photographic evidence.