Reply To: 9.5 Exterior Stairs vs Fire Escape

[John Wilson]

Hi Guys,

Check OBC 3.4.1.4.(1)(d) exterior stairway, and (e) fire escape (conforming to Subsection 3.4.7.). This indicates that they are separate and distinguishable from each other.  Yes these are serving as required egress.

Agreed that if it was considered exterior stair then 9.5.3.3.(1) & (2) would apply and 30 min would be required. The masonry walls easily give that but then I get to 9.5.2.8. for the closures. The challenge there is that under the ‘fire escape’ definition, there are specific parameters which openings need closures but under the ‘exterior stairway’ definition, those parameters don’t exist means even an opening 60′ away horizontally away would technically need to be protected.

The Type 3 reference is straight out of the IFSTA manual for Firefighter Level 1. I forget that everyone here doesn’t necessarily have suppression background – sorry about that. Masonry loadbearing exterior walls with combustible floors/interior walls/supporting elements/roof.

 

Rob, I’m with George, under FPPA, we do not have the authority to order tests like the BCA provides so I can’t tell the owner to have it evaluated. What I can do is go to OBC SB2 2.1.1. and see that 76mm (3 inch) solid brick gives me 45 min. This style of construction (if brick) is typically 2 wythes minimum if not 3 or 4 wythes thick. It’s also reasonable to consider a real stone wall (similar thickness or more) with similar parameters. No need to evaluate the masonry further than that to me.

When considering the cost of evaluation vs replacement, that’s partly where my mind is. Under 9.5.3.7. I can define exactly which openings need closures by the distances specified in Sentence (2). For argument sake, lets say that means 10 windows on the side of a long building. But now if I use 9.5.2.8. EVERY window in the side of the building needs to be protected. That could be a HUGE difference, hence this discussion.