Quick Response Reduction for Ordinary Hazard?

7/27/2020

NFPA 13 (2010 Edition) 21.23 Cleanrooms: 21.23.1.1 Automatic sprinklers for cleanrooms or clean zones shall be hydraulically designed for a density of .20 gpm/sqft over a design area of 3000 sqft.We have a wet pipe system utilizing quick-response sprinklers.

With an ordinary hazard density (.20 gpm/sqft) would I be allowed to use the quick-response design area reduction in Chapter 11?

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9 Comments

Wayne Ammons

7/27/2020 09:31:37 am

I would say yes as long as all of the requirements of 11.2.3.2.3.1 are met.

NFPA 13, 2010 Edition:

21.1.1.1 In addition to the requirements of Chapter 8, Chapters 11 through 21, and Chapter 22, the following special occupancy requirements shall apply.

21.1.1.1.1 All provisions of design criteria in this standard, including design area increases and reductions, shall also apply to these special occupancy requirements.

11.2.3.2.3 Quick-Response Sprinklers.
11.2.3.2.3.1 Where listed quick-response sprinklers, including extended coverage quick-response sprinklers, are used throughout a system or portion of a system having the same hydraulic design basis, the system area of operation shall be permitted to be reduced without revising the density as indicated in Figure 11.2.3.2.3.1 when all of the following conditions are satisfied:
(1) Wet pipe system
(2) Light hazard or ordinary hazard occupancy
(3) 20 ft (6.1 m) maximum ceiling height
(4) There are no unprotected ceiling pockets as allowed by 8.6.7 and 8.8.7 exceeding 32 ft2 (3 m2)

Paul

7/27/2020 10:08:29 am

I second this

JH KANG

7/27/2020 07:23:54 pm

Exactly correct this I understand.
Able to apply area deduction if follow them. NFPA13 2010Ed 11.2.3.2.3.1 (1)~(4)

Glenn Berger

7/27/2020 10:20:55 am

My experience has been when there is a specific criteria listed, the design area reduction is not allowed. Consult with the AHJ as soon as possible.

Franck

7/27/2020 11:02:53 am

As indicated by Glenn, this is not an ordinary hazard classification area but a special occupancy with special requirements.

In the latest edition of NFPA 13 (2019), you have the following (§26.23.2.2) - Approved quick-response sprinklers shall be utilized for sprinkler installations within down-flow airstreams in clean rooms and clean zones. There is no indication for a possible design area reduction.

Furthermore, 0.2/3000 is not on the curve for Ordinary Hazard. OH Gr 2 is either 0.2 over 1500 or 0.17 over 3000.
The O.2 over 3000 is above the OH Gr 2 curve.

It is not on the list of Ordinary hazard occupancies (in the annex section of chapter 4.3 for NFPA 13 2019 Edition, chapter 5.3 in the 2010 Edition)

Ask your AHJ, but I would say no.

If it was on the OH Gr 2 curve and/or if it was defined as an Ordinary Hazard Group 2 occupancy, then I may have say yes, according to what Wayne has indicated.

Dan Wilder

7/27/2020 01:33:36 pm

May want to check Chapter 26

Section 21.1.1.1.1 allowing design area increases and decreases, shall also apply to these special requirements.

Dan Wilder

7/27/2020 01:35:27 pm

Chapter 26 was for the 2019 Edition.

Chapter 21 is for the 2010 Edition as Wayne has indicated above.

Kelly Childers

10/18/2023 07:42:14 am

Do I need to dust seals on my concealed pendant sprinklers for a class six clean room

Moderator

10/18/2023 07:44:12 am

Kelly,

Would recommend submitting as a new question (go.meyerfire.com/ask) so that it can get the response you're looking for. Posting on older threads won't get much traction.

Thanks!

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Quick Response Reduction for Ordinary Hazard?

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