Embed Size (px)
Citation preview
Post Fire Stability
Hans Gerlich
for Winstone Wallboards Ltd
‘Post-Fire’ ‘Stability’
‘Stability’vs
‘Structural Adequacy’
not the same
‘Structural Adequacy’
Ability of a specimen to resist vertical loads, applied
in a standard furnace test
e.g.,30/30/30
Commonly involves lateral forcesnot by test but by design
Designing for Stability
in accordance with
NZBC B1/VM1
During and After fire
Designing for Stability
Of boundary fire walls
FRR based on ‘Time Equivalence’ or ‘S’ rating
based on FLED and constant ventilation conditions FRR rounded (up) in C/AS documents
Post-fire stability required on assumption of
building collapse significantly increased ventilation much lower FRR
High FRR - compartment integrityStability - compartment failure
FRR of Boundary Fire Wall
Post-Fire
NZBC B1/VM1
‘After the fire until the building is either repaired or
demolished’
??
Post-Fire Stability
Many questions remain, such as;
• What are we trying to achieve?• What elements require post-fire stability?• Are the B1/VM1 provisions workable?• Do we have the FRR right? • One way or two-way?
MBIE Work Group
MEFE Thesis – Daniel JessopFire Performance of a Laterally Loaded LTF Structure
Horizontal furnace testISO 834 standard time-temperature curve
30.5 mins – Run-away deflection in fire-rated wall, furnace shut-off
30.5 minutes Run-away deflection in fire-rated wallfurnace shut-down
C/AS1NZS3604
NZBC Compliance
B1 – Structure C 1-6 Protection from Fire
Thanks for Listening !
In short;
• ‘Stability’ vs ‘Structural Adequacy’• ‘Post-Fire’• B1/VM1 provisions• Required FRRs for Boundary Walls• Testing LTF structure (MEFE Project - Daniel Jessop)
