Design Fires for Smoke Control Dr. John H. Klote PE Fire and Smoke Consulting john@SmokeControlExpert.com www.SmokeControlExpert.com

Learning Objectives Provide an understanding of fire growth, flashover, fully developed fire and fire decay. Provide an overview of the basic concepts of developing design fires for smoke control systems.

Extensive Treatment of All Aspects of Smoke Control For more information about design fires, see Chapter 5 “Fire Physics & Design Fires”

Design Fires Used for Atrium Smoke Control and Tenability Systems IBC No Prescribed Design Fires Requires Analysis of Design Fires Many Engineers – New to Design Fires This Talk: Overview of Analysis of Design Fires Focus on Highlights

UK Information on Design Fires Industrial & Warehouse (not high racked) -1990 Smoke Ventilation Association Guide: Sprinklered Steady Fires - 3m x 3m to 9m x 9m. Unsprinkleres Steady Fires – 2 Times as Big Steady Fires in Car Parks – BS 7346-7 Guidance for Offices & Hotels – BS 7346-4 and 5 and in BR368 General Information on Specific Objects: BS 7974 (UK fire engineering standard) BRE design fires database CD

Design Fires Normally Most Important Property - Heat Release Rate (HRR) Other Properties (toxic gases, reduced visibility, etc.) - Tenability Systems For simplicity - Only Discuss HRR HRR of a Design Fire: Steady Unsteady Steady HRR – Peak of Unsteady HRR

Fully Developed Fire Called “Ventilation Controlled Fire” Room with One Opening HRR Controlled by Opening Size – HRR Equation

HRR Measurement Oxygen Consumption Calorimeters HRR per unit O2 Consumed – Almost Constant (13.1 MJ per kg of oxygen + 6%) Open Air Calorimeter Room Calorimeter

Design Fires Normal Fuels - Objects Planned for Space Transient Fuels - In a Space Temporarily Examples: Trash, Stacked Wood Pallets, Furniture After Delivery, etc. Atrium Fires Normal & Transient Fuels No Benefit of Sprinklers (Ceilings > 35 – 45 ft) Transient Fuels: Suggest Min. 2000 Btu/s Non-Atrium Fires Fires w/ Axisymmetric Plume – CFAST Shielded Fires (NIST & NRCC Models)

Questions? Dr. John H. Klote PE john@SmokeControlExpert.com www.SmokeControlExpert.com