Limited Area Sprinkler System

[KLH]

Hello all,

At one time, wasn't there a limit to the number of sprinklers connected to a domestic water system? Thirteen sticks in my head.

Thanks.

 

[SprinklerDesigner2]

A lot of it depends on individual state laws.

In Ohio it was 20 (not sure if that has changed) and in Georgia it is 6.

 

[TravisMack]

Yeah, it is very local specific. I seem to recall St Louis, MO being no more than 6 heads and no more than 4 in a single compartment or something like that. I have seen up to 20 in other areas.

I believe some of the limit has to do with the type of water meter installed on the domestic system. That was the rationale in one of the jurisdictions where I do design work. Basically, anything more than 4 heads flowing would exceed the max flow of the meters. The AHJ was afraid of a piece of the meter breaking off, due to high flows, and obstructing a sprinkler.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[NJ1]

Yeah that seems just about right. Here in NJ is up to the AHJ and water pressure. I have done up to 15 heads protecting mean of egress in two family homes.

 

[stookeyfpe]

In the 2009 IFC, the system is limited to 19 sprinklers.

In NFPA 101, limited area sprinkler systems can have no more than 6 sprinklers and are limited to a discharge density of 0.15 GPM/Square Foot or less.

Based on calculations I've done in the past, and the requirements of the International Plumbing Code, these local area systems cannot support more than 3-4 sprinklers with a discharge density of 0.10-0.12 GPM/Square Foot.

I am not a fan of these systems because they create a false sense of protection and technically are a violation of the IFC because they are never installed in accordance with NFPA 13.

 

[NJ1]

I totally agree with stookey however if the local jurisdiction accepts the job and approve it I guess is ok. I do not believe they are reliable systems but they are the only cost effective solution to the client. Other options are fully sprinkler systems or self contained 13D systems with boosters pumps.

 

[stookeyfpe]

NJ1

I respectfully disagree. My biggest issue with limited area sprinkler systems is they are employed to resolve issues in the IBC for incidential occupancies. Someone using a limited area system for the protection of a laboratory, spray booth, or a rubbish chute room housing a dumpster full of trash or linen and expecting a 10 GPM sprinkler to protect the hazard needs to be working in an industry where they use the statement "you want fries with that." As a former code official, I rarely allowed these systems, and when I did, it was for light hazard uses.

Finally, if a system is not reliable, why select it? Our job is not to appease the code official - its to provide a minimum level of protection that is reliable and meets the requirements of the design standard as well as the adopted construction code.

 

[NJ1]

You right. No argument there but if the Fire Sub Code says that he will approve it then the liability does not fall on me as a contractor. Trust me those systems are very limited specially if someone decides to flush the toilet while a sprinkler head goes off.

Picture this: A landlord builds a wooden deck with stairs as mean of egress on a existing three family home and the fire sub code says that sprinklers are required as water curtains on each door at each floor plus below landings what would you recommend.

Option 1) Sprinklers throughout entire house
Option 2) Sprinkler just the deck with a 13D System employing holding tank and booster pump
Option 3) Install sprinklers out a domestic just in the designated areas.


Option 1 - $ 30,000.00 plus
Option 2 - $ 14,000.00 plus
Option 3 - $ 5,000.00 plus

 

[sspeare]

Somebody "borrowed" my 2009 International Building Code, but I can cite the 2006 edition, as follows:

The 2006 International Bldg Code says:

"903.3.5.1.1 Limited area sprinkler systems. Limited area sprinkler systems serving fewer than 20 sprinklers ON ANY SINGLE CONNECTION are permitted to be connected to the domestic service WHERE A WET AUTOMATIC STANDPIPE IS NOT AVAILABLE."

You can't have a valve blocking the sprinkler flow branch unless the valve is "supervised." Also the domestic service "shall be capable of supplying the SIMULTANEOUS domestic demand and the sprinkler demand ....."

Watch out, 2009 may have changed this stuff. Now, where is my 2009 IBC .....?

 

[KLH]

Thanks all!