Having to do with Draft Curtains and ESFR Systems

[SprinklerDesigner2]

14.2.5 Draft Curtains.

14.2.5.1 Where ESFR sprinkler systems are installed adjacent to sprinkler systems with standard-response sprinklers, a draft curtain of noncombustible construction and at least 2 ft (600 mm) in depth shall be required to separate the two areas.

14.2.5.2 A clear aisle of at least 4 ft (1.2 m) centered below the draft curtain shall be maintained for separation

I have a job where I am using K25.2 pendent ESFR heads where the building is rigid metal frames and 8" bent metal purlins.

The 2 1/2" branch lines will be as high as possible next to the bottom of the purlins so the deflector is a maximum of 18" from the roof deck or ceiling.

14.2.10.1.3 Pendent sprinklers with a nominal K-factor of K-22.4 (320) and K-25.2 (360) shall be positioned so that deflectors are a maximum 18 in. (450 mm) and a minimum 6 in. (150 mm) below the ceiling.

The 24" depth is from the roof deck so if we have 8" bent metal purlins the bottom of the draft curtain can be 1'-4" down from the bottom of the purlin?

And the metal frames themselves are at least 24" deep but what about the 8" space between the top of the frame and roof deck? How well sealed up do the curtains have to be? Cut some sheet metal into 8"x5' strips attached to the top of the frame? Maybe not air tight but pretty close?

Your experience with this and how you handled it would be most appreciated. Seems it would be easy with bar joists but bent metal purlins... I am just not sure.

 

[cdafd]

My less than two cents


910.3.5.1 Construction
Draft curtains shall be constructed of sheet metal, lath and plaster, gypsum board or other approved materials which provide equivalent performance to resist the passage of smoke. Joints and connections shall be smoke tight.

 

[aaron johnson llc]

You may want to take a look at section 14.2.11.1 where the distances are from the obstruction, not just the ceiling.

 

[alchemon]

Your safest bet is to ask the fire marshal. They might require a smoke test to demonstrate performance on what you have built.