NFPA 13, 8.15.4 Vertical Openings and Draft Stop

[staedtlerwtc]

NFPA 13, section 8.15.4 Vertical Openings, specifies a draft stop of at least 18" deep.

1) Where do you measure this 18"? Do you measure it from the top of the ceiling? or do you measure it from the sprinkler discharge?

2) In addition, it specifies the horizontal requirements of sprinklers not more than 6 ft apart and 6in to 12in from the draft stop, but it does not specify the vertical distance in relation to the draft stop.

3) If there are structural steel beams (24" deep) that are installed around the perimeter of the vertical opening, can these steel beams be techincally be used as the draft stop? or do you need to install a draft stop attached to the steel beam? Will the steel geometry effect the sprinkler spray, draft curtain and the overall effectiveness?

I really appreciate any help and clarification.

Thank you!!

 

[cdafd]

Do not have the book in front of me but thought there was a picture showing the set u
I have mainly seen it in anchor stores around escalators

Usually the draft stop is attached to the edge of the opening, so measured 18 inched from the edge down

And the sprinkler head is attached to the smooth cieling there, so to me the sprinkler head is at the top of the draft stop.

Are you just asking a general question or is the above set up a design you are looking at

 

[staedtlerwtc]

Correct the picture you are talking about is attached. It shows the sprinkler flush with the ceiling, however the design I'm looking at is not. It is approx. 10 inches below the ceiling.

Thanks for the assistance.

 

[cdafd]

ok now I see the question

good one


if you are at bottom of the opening and have at least 18 inches or more down from that, it looks like you meet 13.

than head placement should be per 13 down from the actual cieling and looks like you meet that section for both.

there is no minimum or max thickness on the draft stop per 13


"""Will the steel geometry effect the sprinkler spray, draft curtain and the overall effectiveness?""" would say no

hopefuly some others will chime in with an opinion

 

[staedtlerwtc]

Thanks for your input cdafd. Hoepfully I can get further opinions from other members.