Measuring lift door air leakage rates in modern high-rise residential buildings

Abstract

This paper investigates air leakage rates between the common corridor and the lift shaft within modern high-rise residential buildings via the lift doors. A literature review has been undertaken which indicates that leakage areas for lift doors are suggested as being between 0.047 and 0.060 m² with only the latest version of BS EN 12101-13:2022 indicating that a reduction may be necessary to 0.020 m² for more modern buildings. Leakage areas have been investigated for a 22 storey residential building by recording on-site flowrate and pressure measurements whilst a lift car is in operation as well as attempting to measure the gaps across a set of lift doors. The maximum instantaneous flowrate measured was −89 L/s into the shaft and +99 L/s out of the shaft. The largest pressure change recorded was a depressurisation of −22.5 Pa and the highest pressure recorded was +19.5 Pa. These values result in a maximum calculated leakage area of 0.020 m² for this building. This value is approximately half of the lift leakage area previously quoted in BS EN 12101-6:2005, however is closer to the suggested tight lift door value of 0.020 m² in BS EN 12101-13:2020 and would indicate that these are more appropriate for use in analyses of modern buildings.

Practical application

When undertaking computational fluid dynamics (CFD) modelling of smoke control systems within the common corridors of residential buildings, leakage values can be used for lift doors based on values quoted in BS EN 12101-13:2022. For a pressurisation system design, it is more onerous to use larger values, however, when designing a mechanical extract or depressurisation system, a lower leakage rate is potentially more onerous. This paper shows that the use of lower lift door leakage values from the standard as being more appropriate for use as input conditions within CFD simulations.