CROSS UK – Collaborative Reporting for Safer Structures (CROSS) – has published a report on the stack effect and considerations for smoke control. CROSS is a provider of free safety information for the built environment and publishes safety information based on reports it receives and information from the public domain.

This new CROSS report addresses issues and recommendations relating to the stack effect - a natural phenomenon that occurs predominantly in tall buildings, where difference in air temperature results in pressure between the inside and outside of a building and causes air to flow through vertical spaces.

Stack effect can significantly impact fire safety and smoke spread in the escape stairwells of tall buildings. Reports suggest that real world tests have demonstrated that existing smoke control systems, designed in accordance with standard industry design guidance and idealised conditions, may not suitably account for typical winter stack effect conditions.

Aimed at designers and installers, the report recommends that when modelled, smoke control systems such as smoke extract shafts should account for realistic building and environmental conditions to demonstrate they can overcome the powerful and competing air flows driven by the stack effect

The report outcomes also advise that testing and commissioning of smoke control systems should not be done in isolation but should be carried out in realistic and suitably representative building conditions to capture the impacts of the stack effect.

The full report can be viewed here.