What is the Design Area for a Deluge System?

11/16/2021

What is the minimum design area for a deluge system?

NFPA 13 only specifies the design area for wet-pipe and dry-pipe systems.

Is the design area the entire system?

Many thanks!

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11 Comments

Dan Wilder

11/16/2021 06:36:21 am

It depends.....not the greatest answer but as a general approach, you'll need to know what is being protected.

For open sprinkler deluge systems, the entire system becomes the remote area. In other cases, there may be a requirement to discharge 2 or 3 systems at one time (We have a transformer project that is required to discharge the two adjacent transformers in addition to the transformer that may be on fire). Cooling towers also fall under this requirement in NFPA 13 in certain conditions.

For closed head systems it is based on the protection use and applicable NFPA... an example is in NFPA 409 it's 5,000 FT² for Group II Aircraft Hangars.

Anthony

11/16/2021 08:25:29 am

NFPA 13-2016 23.5 Says to see a different standard.

I'd start with NFPA 15 the standard on fixed water spray.

However a good rule of thumb is 'if its going to flow it should be calculated." All the heads are open and are going to flow when a deluge system operates so all the heads must be calculated. NFPA 13 always has a 7psi end head minimum so keep that in mind when running calcs.

If this is for a proscenium as detailed under NFPA 13-16 8.15.17 then its the whole deluge system at 3 gallons per lineal foot.
See 11.3.3 ( 2016)

CJ Bonczyk

11/16/2021 09:07:05 am

As Dan has stated above it will depend on the occupancy and what the system is protecting. Deluge valves are used in preaction, open head, nozzle type, monitor nozzle systems, foam, etc.

If the sprinkler system is open head, it will be the entire area/every head as per FAQ [8.3.3] in the NFPA 13 2019 Handbook.

Important items to consider are water supply capability, system sizes, monitoring/supervision, system bracing & possible surge tanks for water hammer issues. Return bends are not allowed. Depending on the size of the deluge system, if it's a large capacity type it can exceed the pumping capacity of the fire department.

Pay special attention to the items outlined in Special Occupancy requirements in the later chapters of NFPA 13.

Jon link

11/16/2021 09:13:01 am

For Deluge system or water spray system, NFPA 15 will be the reference code... It will guide you on your design

Jesse

11/16/2021 09:30:46 am

It depends. And I'm presuming this is an open-head deluge system.

Necessarily, if its an open head deluge system your entire area is being calculated. Additionally, depending on the occupancy hazard class, you may be adding in adjacent systems to the demand.

13 addresses some deluge type systems, as do NFPA 15 and NFPA 409 if its a hangar.

Franck

11/16/2021 10:10:00 am

The minimum area is the entire system controlled by one deluge valve. As all heads are open, you cannot consider the discharge of only a portion of them.
Then, when you design several adjacent deluge systems, as it would be the case with adjacent transformers, a large hydraulic cellar with adjacent deluge systems, or a cooling tower with adjacent cells, then, as indicated above, it all depends on youir configuration. It could be only one system id separation distances are sufficient or if adequate fire barriers are provided between 2 adjacent systems. Or it could be 2, 3 or 4 systems at the same time if you consider the worst place to have a fire : at the intersection between different systems.

Jack G

11/16/2021 01:46:41 pm

Yes—- open heads, entire system or systems.

Alex

11/17/2021 06:00:14 am

Minimum area would be any heads assumed to open during a fire. Therefor, if your heads are open, calculate the entire system. For multiple systems, see NFPA 15

sean

12/31/2021 06:48:36 pm

all of them

Omar

1/8/2024 07:52:22 am

According to NFPA 16, section 7.3.7 : for foam water wet pipe , dry pipe and preaction system the total design area shall be 5000 ft2 (465m2).

rina

4/1/2024 07:57:05 pm

May I know why the deluge system is a must 7 psi?
what is the 'history' behind the 7 psi.... (since most of ''aging'' asset unable to stand 7psi anymore..)

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What is the Design Area for a Deluge System?

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