| Abstract | This report provides a historical analysis of the spatial separation requirements in the National Building Code of Canada (NBC), focusing on the development of Articles 3.2.3.1. and 3.2.3.2., Tables 3.2.3.1.-A to 3.2.3.1.-E in Part 3 and Articles 9.10.15.1. to 9.10.15.4., Tables 9.10.14.4.-A and 9.10.15.4. in Part 9 of Division B. The analysis is primarily focused on the 1958 St. Lawrence Burn Tests, particularly the fire tests conducted on Building Nos. 4 and 5, which established foundational data for radiant heat exposure and incident heat flux that formed the basis of these requirements.
The report documents the development of the spatial separation tables and associated requirements from the St. Lawrence Burn Tests to more recent changes associated with the concentration of openings and fire department arrival time. This includes a detailed discussion of the results of the St. Lawrence burn tests and the conversion of those results into the specific spatial separation requirements that exist in the current 2020 NBC, including the modifications that have occurred since.
Recommendations include reviewing the applicability of the flame front factor used in the development of the spatial separation table values, reconsidering the 10-minute fire department arrival time assumption, reassessing concentrated openings in the context of the enclosing rectangle approach used in the UK and New Zealand, and extending themethod for calculating unprotected openings for staggered and skewed building faces from Part 9 to Part 3 buildings. |
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