Sprinkler requirement for warehouse

[PrakMS]

Hi Guys,

I have the following situation in one of the projects i'm managing.
(Sorry for the length of the post, just thought that sometimes the question gets mis-interpreted if enough data is not provided)

The background goes like this, we are constructing a warehouse in 2200 Sq.m area with no internal compartmentalization. The warehouse height is 7.2 m and the building is having a roof truss arrangement. The storage racks for a height of 6 meters (3 levels) and the aisle width is 3.2 meters. The material inside is rubber, gloves, packing materials and non-flammable chemicals. We had hired a fire consultant to design the system as per NFPA, now the consultant has given his output and i'm having lot of clarifications in that output.

The consultant's outputs are as follows:
200 nos of Upright sprinklers with K-factor 115 for entire warehouse (to sprinkle the ceiling structural members)
200 nos of Pendant sprinklers with K-factor 115 for the entire building
1704 nos of In-rack sprinklers (one sprinkler head for each pallet unit) (including the top level)
3 nos of fire hoses or hose reel drums inside the building at various points
8 nos of stand posts /external hydrant posts around the warehouse
Underground water tank of capacity 350 KL with 2 pumps of 273 CMH (1 diesel + 1 electric) and 1 jockey of 10.8 CMH

My clarification is very simple, whether you need a sprinkler head for each pallet unit and also how to calculate the water demand for the entire fire protection system (including sprinklers+fire hoses+stand posts which i have mentioned)

It would be of great help if you guys can clear this up.
Thanks in Advance....

 

[SprinklerDesigner2]

How are the rubber gloves packaged? Be detailed.

Are the shelves solid shelves or pallet loads?

Be more specific on building construction. What is the pitch of the roof? How is the roof constructed? Is there a suspended ceiling involved because with 200 uprights and 200 pendents I have to conclude there's a suspended ceiling and the structure above the ceiling is combustible?

 

[PrakMS]

the rubber gloves are stored in 50/100 kg bags, packing materials are in rolls, carton boxes and bags. The shelves are pallet loads, the building construction is as follows:
building size is 55.3 m X 35.4 m
roof pitch is 1:2, the building has a center column on the 35.4m side and below is an elevation of the building

no it is not a suspended ceiling, the ceiling is made of structural steel in roof truss design. My apprehension is about the consultant's proposal to have upright sprinklers for the roof truss(steel). do we really require such a protection.!!!

 

[PrakMS]

i'm reposting the picture.

 

[SprinklerDesigner2]

Your picture doesn't work.

You said the roof pitch was 1:2 but 1:2 what?

If i were approaching this the most important thing for me to know is exactly ow the roof is constructed and does the roof pitch exceed 2" in 1'-0" or 0.169 meters in 1.0 meters?

What does the roof truss/supporting steel look like?

You said the building was 7.2 meters (23'-7 1/2") high and is this the highest point, lowest point or what?

2,200 sq meters is only 23,680 sq ft.

A properly designed ESFR system can solve a lot of problems but as good as these systems are they aren't always the best or appropriate answer because an ESFR system is so picky as to exact roof pitches, size and placement of steel roof structures, how lights are positioned and everything else that goes into making a proper analysis.

Let's assume it is possible to install an ESFR system in this building while clearly remembering it may not be an appropriate answer.

In NFPA #13 2013 edition TABLE 17.2.3.1 "ESFR Protection of Rack Storage Without Solid Shelves of Plastics Commodities Stored Up to and Including 25 ft (7.6 m) in Height"

You want "Single-, double-, and multiple row racks (no open-top containers)"

with storage "Exposed nonexpanded" and does not have solid shelves.

With storage up to 25'-0" (7.62 meters) in a building with a maximum height 30'-0" (9.144 meters) using K16.8 ESFR sprinklers the minimum discharge pressure would be 35 psi or 99.4 gpm from each of 12 sprinklers. Minimum theoretical discharge would be 1,192.8 gpm which would jump to somewhere around 1,250 gpm. this is 4,731.76 liters. Add 250 gpm and the total water needed will be right at 1,500 gpm or 5,678 liters.

The good part about an ESFR system is sprinklers in the racks are not required as long as you do not have open top containers or solid shelves.

Water supply duration most likely will be 60 minutes which will require a stored water supply of 90,000 gallons or 340,687 liters.

Requirements for fire hose inside the building varies greatly from state to state as I am sure it does around the world. In Georgia you will not find any hose stations for occupant use anywhere in any building especially something with plastic storage in racks. The feeling in Georgia, and I agree with this, is if a fire involving plastics can not be contained by ESFR sprinklers the last thing you want to have happening is untrained people attempting to fight a fire with a 1 1/2" fire hose. If the fire gets that hot it's time to evacuate everyone and leave the fire fighting up to the trained professionals.

I want for you to keep in mind this advice is worth exactly what you are paying for it and that's nothing. I look at something like this like a fun puzzle, it's Saturday night, I'm getting ready to retire and I'm bored.

 

[LCREP]

Another option is to look at

Chapter 21 21.1* General.
Alternative Sprinkler System Designs for Chapters 12 Through 20 in NFPA 13. This is based on FM Data Sheet 8-9.

Table 21.3.1 Extended Coverage, CMSA [K-Factor 25.2 (360) Pendent] Sprinkler Design Criteria for Single-, Double-, and Multiple-Row Racks Without Solid Shelves of Class I Through Class IV and Cartoned Unexpanded Plastic Commodities

IF you meet the commodity limitation as noted above, 6 heads @ 30 psi about 828 GPM for 60 mins= about 50,000 gallons. The hose demand is the same as ESFR. Only down side is it is control mode vs ESFR. But maybe a better alternative to .60/2000.

You see you have many options, that is why you need someone who knows fire protection to be involved.

 

[LCREP]

Park,

If you look at the other question you posted regarding your design, see below on how large the tank will need to be.

Density= .60
Design area= 2000

.60 x 2000 = 1200 GPM. The actual number will be higher depending on the system layout, this is for estimate only, it could be 5-10% higher.

If this is a NFPA designed system the duration is 120 mins

120 x 1200= 144,000 gallons.

Interior hose stations and any fire hydrants would need to be added to the 144,000. At minimum 500 GPM x 120 = 60,000 gallons

144,000 + 60,000 = 204,000 gallons

However if you review at what SprinklerDesigner2 proposed and what I did above you can see the tank size can be significantly less.

As noted above you have many options in NFPA 13, the old .60/2000 is great but when you have a tank and or limited water supply you need to use some of what is new. Remember these designs are based on full scale testing so we know it will work.

Good luck.

 

[SprinklerDesigner2]

LCREP,

If I understood Prak correctly he said some plastic was on rolls which I assume would be exposed non-expanded plastic.

Given the size of the building, around 25,000 sq. ft., the cost of the overhead sprinkler inside is miniscule approaching the area of being irrelevant.

I've put many similar overhead systems in for as little as $0.90 per sq ft and it is hard to think of something that would run more than $1.50 per sq ft unless you had sprinklers in the racks which most likely you wouldn't.

All the costs associated with this project will be outside; the water storage tank, the underground and the pumps.

It seems engraved in stone down south a water storage tank will cost $1.00 per gallon. A 90,000 gallon tank will cost $90,000 while a 204,000 gallon tank will cost $200,000 or better. The cost difference between the to tanks could easily pay for the inside sprinklers three times over so the whole idea should be to get the tank and pump size down to as little as possible.

 

[LCREP]

Design 2,

I did not pick up on the exposed plastics, if present then the 6 head design is not going to work. But that 6 head design would be the way to go for a smaller tank size which as you said will be the driving cost on the job.

The 6 head design is really something compared to the 20 head 2000 sg ft design area. In testing I think they had fire control with 3 heads which is amazing. Gives you an idea where this industry is going.

10 years from now sprinkler design will be completely different. Too bad we will be both retired!!

 

[SprinklerDesigner2]

Lcrep,

But I watched it go from being 95% pipe schedule using standard response to where we are today. Hard for some to comprehend the vast majority of FM jobs in the early 70's were pipe schedule. I remember warehouses with storage greater than 12' where FM told me to use extra hazard pipe schedule because that was all we had. We never took a flow test we just did what the insurance company told us to do.

I will probably never retire retire because I want to be around watching the change.

 

[stookeyfpe]

Dang, I missed out on a interesting conversation. Too bad I spent the weekend drinking bourbon, riding my bike, and catching black bass (not in any particular order).