(1) UMIST, Manchester, England;(2) Wormald Ansul (UK) Limited, Manchester, England
Abstract:
The paper extends existing methods of calculating the hold time for a fire extinguishing gas in an enclosure to cover mechanical HVAC systems and wide descending interfaces, and compares the wide descending interface model's predictions with some experimental data. A simple approximation to the measured wide descending interface gives conservative hold time predictions, while the sharp descending interface model used in current standards gives optimistic predictions.