Quick-Response with Standard in Corridor?

4/22/2020

NFPA 13 (2019) Section 9.4.3.2 states that quick-response sprinklers shall not be mixed with any standard-response within a compartment unless some conditions apply.

9.4.3.2 Where quick-response sprinklers are installed, all sprinklers within a compartment shall be quick-response unless otherwise permitted in 9.4.3.3, 9.4.3.4, or 9.4.3.5.

Those conditions don't apply in my case and I know there's a definition of a compartment in 3.3.38.

However, from a practical standpoint if the compartment in question is a corridor, would you include the adjoining offices in the compartment? These offices are likely to have their doors open and are not on any magnetic door closing devices.

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6 Comments

Wayne Ammons

4/22/2020 08:22:40 am

A compartment can have openings to the adjoining space up to 8 ft. wide as long as there is an 8" lintel from the ceiling and a single opening (such as a door) 36" wide without a lintel. Is your scenario different than what the definition describes?

Dan Wilder

4/22/2020 08:38:14 am

Change the sprinklers in the corridor to all be SR (match existing conditions I am assuming) unless the adjoining offices also do not comply with the definition of a compartment, then you are on the hook for the complete change out. This is allowed per 9.4.3.1(5).

Franck

4/22/2020 10:28:42 am

I won't be too much concerned in your case.

As indicated by Wayne, as long as you can consider that the wall above the door or other opening that is open can act as a draft curtain, you can have different type of sprinkler heads on either sides.
The issue with having standard response and quick response in the same area (same ceiling and same elevation) is that a fire below the standard response heads may operate first the quick response heads. This means that you will have more water damages as you will open more heads. In some adverse conditions, you could even overtax your sprinkler protection (room design method or very small design area of application with a mix of different sprinklers).
But this would be the same, up to a certain point, if you mix ordinary and high temperature sprinklers.

You will have the same type of issues when using ESFR in an area where you have standard sprinklers. In that case, it is good practice to provide a draft curtain of noncombustible construction to separate the two areas.

As Dan indicated, it is also common sense to use a single type of sprinkler, if possible. If you remove the problem, you find the solution :)

Mike

4/22/2020 03:35:18 pm

What is the occupancy? If it is light hazard, aren't QR heads required?

Daniel

4/23/2020 04:44:28 pm

It would normally be light hazard but it's ordinary based on the jurisdiction. The issue is the ones in the corridor need to be changed to QR out to deal with a ceiling pocket issue. The question is if the ones in the adjoining offices also need to be changed since typically people have the doors open. While I don't think they have to per the compartment definition, it may be practical to do so.

Mike

4/22/2020 08:37:40 pm

If the OP is talking from a practical standpoint, use QR response matching QR sprinklers already installed.

Avoids, conflict with plan check review comments, fitter confusions, head box spare sprinklers, listing and ordering.

Why would anyone go through the trouble of creating a separate sprinkler symbol, BOM, etc. for SR response sprinklers is beyond me. Think about listing, ordering, installation and head box. Lots of questions and comments on this board just show no practicality.

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