Designing a sprinkler system with hose reels for a supermarket 1

[rbarnswell]

I need some clarification on this matter.

The area that needs to be sprinkled is 5,864 square feet. I would classify the area as Extra Hazard based on the definition in NFPA13. Using the area-density method i would get approximately 1,319 GPM. The I am not sure what to do next. From table 7-2.3.1.1 the required water supply duration is 90 minutes.. This would mean i would need 118,746 gallons for the 90 minutes. How do I incorporate this with the hose reels (standpipes) that I would like to add? Can i use 1 pump for both the standpipes and the sprinkler system. I would need a total of 6 standpipes. The class standpipe is class 2. Can somebody tell me how to go about this please.

And if i never had the sprinkler system and i was just going with standpipes (forget that the building is a supermarket) and i have 6 standpipes. Since it is a class 2 that would mean the flow required is 100 GPM for the most remote standpipe and also the required water supply would be 6000 gallons. (since for this class you would not add for additional standpipes) That is what i got from the code. I hope i am correct. Am i correct?

Would greatly appreciate the help .. really need to finalize this.

Regards,
Ramone

 

[cdafd]

Why the extra hazard??? What are they storing and how high, that requires the eh????

Why the standpipe???? Most codes the standpipe falls out once you sprinkle???

Do you know what building code and edition this is built under???

 

[rbarnswell]

Ok.. maybe I am not correct with the hazard. The sprinkler is only for the storage area for the supermarket. There will not be any sprinklers within the supermarket's shopping area. I am not sure on how high . But I assume up to 10 feet.

The standpipes are for the front part of the building and within the supermarket's shopping area. As for the building code i am not sure. I can find that out. So what do you think? Can you help me figure this out?

 

[Oremus]

Can I ask what field you are approaching this from? Architect, mechanical, or fire protection contractor?

 

[rbarnswell]

Oremus ... mechanical

 

[cdafd]

The design depends on what they are storing, how high they are storing, and how they are storing
Suggest get with a fire sprinkler company and talk to them

Who is requiring the standpipe system???

How many sq ft is the rest of the store

 

[rbarnswell]

would it be ok to have the sprinklers within the shopping area of the supermarket?

the rest of the store is 8,500 sguare feet.

Perishable packaged food items, canned products. Basically all the usual items within a supermarket. There is also a cold room for products that need lower temperatures. i have no information on how high but i have assumed 10 ft. There will be shelving and storage racks for storage on pallets.

 

[cdafd]

Do not assume, that is how sprinkled buildings burn down

Yes not that much more to sprinkle

 

[Oremus]

Rbarnswell, it sounds like you're in over your head. I'd turn it over to your local fire protection contractor / fire protection engineer.

 

[stookeyfpe]

Rbarnswell,

Don't be offended but I suspect your being asked to design an automatic sprinkler system and you are not in North America. You mention a code and hose reels inside a grocery store, which is classified as a Mercantile in the U.S. model codes. In the US, we require automatic sprinkler protection in Mercantile occupancies with a fire area > 12,000 square feet. Hose reels are never required.

Tell us this:
1) What country are you in?
2) Can you cite the applicable code sections you're seeking guidance on?
3) What does the specification require?

From my perspective, Class II standpipes (including hose reels) are dangerous to use by individuals not trained in operating fire streams. If you haven't been trained in operating a hose stream flowing 100 GPM @ 65 PSIG, the time to learn is not during an incipient fire.

Your entering into an arena where a qualified fire protection engineer needs to be engaged.

 

[rbarnswell]

1) I am in Jamaica
2) Table 7-2.3.1.1 and 7-2.3.1.2

For 5,864 sq ft i would get 1,173 gpm based on the tables mentioned above.

for 90 minutes i would have 105,570 gallons. This is an extremely large amount of water.

Yes I know i need to contact a Fire Protection Engineer but in my country I know they are not many of them. I would like to become a fire protection engineer myself. any idea of colleges?

 

[TravisMack]

I have done a fair bit of work in the Grand Bahamas and assume you may have similar codes.

1 - Your design density is only over the calculated area, not the entire protected area. So, if you are doing 0.20 gpm / sq ft over the most demanding 1500 sq ft, then you only have 300 gpm + overage. At 90 minutes, you are looking at 27k+ gallons.
1a - Check your local building code for local requirements on minimum end head pressure. I have found that some of these islands have specific requirements for minimum end head pressure. Some jurisdictions require 25 psi minimum pressure. So, even if your sprinkler only need 20 psi, you have to bump it up to 25 psi. This will increase your system demand, and lead to an increase in stored water supply.

2 - It sounds like you are talking about a pump / tank system. Your pump capacity would be based on your sprinkler demand, or standpipe demand, whichever is higher.

3 - Check your local building code for the standpipe requirements. I have seen projects in the Carribean where we just do standpipes and the code has demands of 65 psi at the outlet at 100 gpm. They also want to be able to flow every hose on a floor. So, if your store has 4 standpipes connections, you are going to be looking at 400 gpm for your demand. This will affect your pump / tank sizing.

Basically, you really need to look at the local building code as that will have a large impact on what the requirements are for the particular system.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[rbarnswell]

ok thanks much Travis. This information helps a lot. I will keep you updated on my progress.

 

[stookeyfpe]

Thanks again Travis. Very helpful as always.

 

[rbarnswell]

WHAT IS THE REQUIRED PRESSURE FOR WET TYPE SPRINKLER SYSTEMS?

 

[Oremus]

Minimum psi for a sprinkler is 7 psi. There is no minimum required psi for a system. It is whatever the calculations determines it to be.

 

[rbarnswell]

OK. and what is the standard pipe size for sprinkler branch pipes? is there a maximum number of sprinklers allowed per riser? I know all about the distance between sprinklers already , i am just not sure how to go about doing the branches.

 

[TravisMack]

There are no standard sizes for branch lines. It is whatever you calculate the system to be. You want to use pipe sizing that provides the most efficient installation and fabrication.

There is not a maximum number of sprinklers per riser. There is just a maximum sq ft per system.

I hope that helps.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[rbarnswell]

are there fire rated pumps that are completely submersible?

 

[Oremus]

Someone will correct me if I'm wrong but I don't think so. I think the closest you'll get to 'submersible' is a vertical turbine pump.