Vehicle garage - sprinkler selection 4

[HVAC-Novice]

I have a diesel truck vehicle garage and we are adding ducts over 4' wide. So I need to hire a contractor to add sprinklers under those ducts. I've been researching IBC and NFPA 13. I need to prepare bid documents for a sprinkler contractor. They will perform detailed design. But I need to show number and type of sprinkler heads. Could someone look at this and tell me I'm on the right path?

My plans would show location of sprinkler, temperature, response time, and coverage

How do I determine the Commodity and Occupancy classification?
- trucks are diesel and some occasional gasoline vehicles; there are some misc. tires stored (but it isn't a real tire storage). Most stored items are made of steel or concrete. Some steel items can be on a wooden palette. Some fluids (Diesel DEF fluid) are in plastic tanks). Nothing stored is taller than 5-6 ft.
- Based on this classification this could be Class I or Class II. Can we ignore the trucks having fuel?

Based on NFPA 13 Table 4.3.1.7.1.1. Class I or II stored would be Ordinary Hazard I

If I use standard range sprinklers and Ordinary Hazard, NFPA 13 Table 10.2.4.2.1 (b) shows me a maximum spacing of 15 ft.
- why is there no OH I or II in those tables?

If I use Extended range sprinklers, NFPA 13 Table 11.2.2.1.2 shows me up to 20 ft spacing. but also shows me smaller numbers (down to 12 ft)
- Can I just arbitrarily decide to use extended range sprinklers?
- what determines if I can use the 12 or 20 ft? The table is a bit unclear and since the standard range is 15', what is the purpose of an extended range 12'sprinkler?
- Again, why does Ordinary Hazard "I or II" not matter here?

Other than that, I plan to use Quick Response and 135°F types. There isn't a heat source nearby. Maybe a truck could park idling under the duct, though. But I don't think that would heat the area that much. Summer can be close to 100°F, so maybe i go to 175°F sprinklers. IS there any reason a higher temperature rating is forbidden?

Thanks in advance. and I already signed up for a 3-day Fire Protection design Class to learn this better. But that is in September and I need to bid this out now.

Edit: NFPA13 A.4.3.3.2 shows Automobile garages as "Ordinary Hazard II". I still don't understand why "I or II" matters since it isn't mentioned in the sprinkler tables. I assume it matters elsewhere.

 

[LCREP]

I do not understand why you are doing the design for the project, it is the sprinkler contractor job, so let him do it. You design you just taken on all the legal responsibility. Have him submit the plans to the local AHJ and insurance carrier, your butt is covered!

You should say must be installed as per local and national codes…period!

My 2 cents working on the insurance engineering side for way too many years.

 

[HVAC-Novice]

They will need to have an idea how to bid this. They won't do a design before submitting a bid. So they will need to have some idea what Hazard Class this is, and what the exact scope area is.
I just looked at some larger projects consultants designed for us. Those also show the hazard classification of the areas and the gpm/ft² etc.

In some cases a sprinkler contractor bidding on this (sprinkler is the only scope in this bid, the rest of the project already is under contract) also wouldn't see where there is heat (for needing higher temperature sprinklers)

And for some projects we also show the coordination of sprinklers vs. light fixtures etc.

This is design-bid-build. So I bid this out, and we select the lowest bidder. And in addition, I still want to understand how it works :-0

 

[LCREP]

Wow I hope you have adequate insurance coverage….

A few comments

1. What is the existing sprinkler design?
2. Are you just adding ductwork or entire new sprinkler system?
3. The ductwork sprinklers should be the same temperature , size, etc. as the ceiling sprinklers.
4. If you have space heaters or any devices producing heat the temperature of the sprinkler maybe higher, NFPA 13 has a chart with the temperature requirements.

You may want to contact a fire protection engineer for details and advise. You have one chance to get it correct. Should a loss occur it will be very easy to see where mistakes were made. The sprinkler contractor will provide his contract that says you provided the design. That is where the fun starts…..

 

[HVAC-Novice]

The ducts will be installed in an existing building with existing dry sprinkler system from around 1981. So this is just to cover the areas under areas under the NEW ductwork and Make-up air unit.

Maybe I should show less on the plans and leave it more vague... Some plans (by consultants) show the hazard classifications on the fire protection plans, but no sprinklers. Their architectural plans show sprinklers on reflected ceiling plans where they have ceiling tiles. but I bet they just placed them schematically.
but on other projects I saw the consultants provided the full piping layout to determine if the water connection is sufficient.

I guess I could leave exact type, coverage, and response time to the contractor. But I may want to list the temperature rating? Or should I just list the ceiling temperatures and they can figure that out what and how many sprinkler to use?

Does NFPA define what ceiling temperature to assume? i only found table 7.2.4.1 that shows what tu sue at what assumed ceiling temperature. Like one duct could have idling diesel trucks underneath. and if in summer it is 100°F, the air above the truck could be 150°F (no idea) that would be a 175°F sprinkler. But what stops me from assuming 225°F and using a 259°F sprinkler? On the other hand I don't want to leave that totally t the contractor.

We recently had the case that we tested a new generator. Apparently that got a bit warmer and the sprinkler went off. We have a higher temperature sprinkler added. But it seems an arbitrary decision what rating to use.

 

[LCREP]

What are the ceiling temperature sprinklers? Take look, no color ordinary 165, intermediate 212 white, high blue 286 on the frame of the sprinkler. Sometimes you get lucky and the spare heads in the box at the riser will have them, check the date on the head.

If this was once a warehouse it could be 286 high temperature given the age of the building.

The less detail you provide the better, reference the codes as I noted above.

Dry systems have a lot more to be concerned about ie low point drains, inspector test connection, etc. You may need a separate dry pipe valve depending on the number of heads you are adding. Make sure the system is operation ie full trip test on the entire systems.

 

[cdafd]

Bid::: design to NFPA 13, adopted by the ahj.

That is what they get paid for.

As LCREP says there are other factors, especially with dry system

 

[HVAC-Novice]

OK, I get checked out what the existing sprinkler temperature rating is. I also found NFPA 13 9.4.2. gives some guidance for temperatures.

And it even looks like the code wants to use higher temperature sprinklers. There is a FAQ for 9.4.2.4. that explains that lower temperature sprinklers may start outside the fire area and with that diminish water flow to the sprinklers actually above the fire.

Maybe I just mark the areas needing sprinklers (under duct and new MUA) and indicate the hazard Classification.

 

[cdafd]

HV
Maybe state what you need and let the sprinkler company do what they do.

Just as in hvac,,, there is more than one way to skin a potato.

 

[Danefre]

Sorry to say this but this needs to be a deferred submittal. State on the drawings: "Design per NFPA 13 and all local codes and amendments" and leave it up to the contractor. The work you are trying to perform is done by registered FPEs that carry liability and E&O insurance. Since you're not qualified to spec the system - cover your rear and pass the buck.

As a contractor I can tell you that we'd way rather bid on a deferred submittal rather than incorrect bid drawings. You are opening yourself to liability by doing this. If you want to help the bidding process then perform a hydrant flow test and leave the rest to the contractors.

 

[HVAC-Novice]

All good points.

Would there be an issue to label that the area in question is Ordinary Hazard II? That's what I had seen on plans consultants did for us. Beyond that I will just mark the area in question (area under ducts). I will leave everything else to the contractor.

 

[Danefre]

Just my opinion, but if you do label it OH2 and the contractor bids it that way, goes through design and submittals and the AHJ kicks it back saying it needs to be Extra Hazard, then all the fingers will be pointed at you. Owner will not be happy with a change order due to engineering deficiencies. There is really no shame in leaving it unspecified and letting the contractor figure it out. They WILL identify in their proposal what THEY think it needs to be designed to. This alleviates any responsibility from your side.

Half the projects we bid don't even have Fire Protection drawings so it's really not a big deal. Just my 2 cents. Good luck!

 

[SprinklerDesigner2]

I 100% totally agree with Danefre:

Sorry to say this but this needs to be a deferred submittal. State on the drawings: "Design per NFPA 13 and all local codes and amendments" and leave it up to the contractor. The work you are trying to perform is done by registered FPEs that carry liability and E&O insurance. Since you're not qualified to spec the system - cover your rear and pass the buck.

You said "The ducts will be installed in an existing building with existing dry sprinkler system from around 1981"

I started designing systems in 1975 and from 1975 to the early 1980's almost everything we did was pipe schedule system because it was before personal computers came out and all calculations were done by hand. Is the system pipe schedule? If so you could have a huge problem depending on the AHJ.

Trust me on this, throw that monkey at the licensed fire sprinkler contractor and leave it alone.

 

[FacEngrPE]

You should also review the applicable building code, Ch 3 Use and Occupancy.
Your description indicates more than one possible answer, the AHJ plans examiner will want to see use and occupancy on the plans, and it is a necessary input to the sprinkler contractors design. Consult with the clients underwriter and / or a certified protection engineer when validating occupancy. Getting use and occupancy wrong will cause trouble later.

No you cant ignore the trucks have fuel. And that sometimes repairs require draining and unmounting fuel tanks if service work is performed in this garage.

 

[HVAC-Novice]

Our garages all are S-2. No repairs are performed. In practice, they may mount and un-mount snow plows. There is a separate area that is an actual truck shop with actual lifts etc. (not part of this scope).

I work for the owner. I'm not stamping anything .