Thanks Scott. Yes, that does help zero in on when it went from open to closed sprinklers. I've recently modeled activation with and without a draft stop for 3,6,9,12,15, and 18 inch deflector distance, for 135F, 155F, 175F, and 200F Sprinklers 9" from edge of opening splitting the difference of 6 to 12. I remember seeing the detail when open sprk deluge was required I just can't recall if there was draft stop or not.


Quoting Scott Futrell <>:

Seems like a fun research project Brad for a Friday afternoon.

From the 1955 edition,

621: Open sprinklers may be used to protect special hazards, for protection against exposures, or in other special locations.

777 (c): Where vertical openings are not protected by standard enclosures, sprinklers should be so placed as to fully cover them. This necessitates placing sprinklers close to such openings at each floor level.

I don't see anything else. Maybe narrows it down to 1955-1969.


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-----Original Message-----
From: Sprinklerforum [] On Behalf Of
Sent: Friday, April 06, 2018 12:15 PM
Subject: NFPA 13 prior to 1969 edition

Does anyone have access to 13 where the water curtain detail still required open sprinklers (deluge)?

I'm curious if the draft stop is required.

Besides smoke protecting the opening it occurred to me the other day the draft stop would help form a 'wall of water' by blocking ~9 gpm, making it drop straight down, and thereby providing a density of greater than 1 gpm/sf around the perimiter.




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