Is there anything in NFPA 13 that forbids multiple pipes (two, in this case) being supported by a single trapeze?

Assumption here would be that the trapeze has been accurately calculated to support the combined weight of the two pipes (per NFPA 13 Chapter 9, 2016 Edition).

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I'm being asked to provide sprinkler protection for emergency electrical feeders for a highrise hotel. NFPA 70 (2014 Edition) Article 700.10.D.1 states:

"Feeder Circuit wiring shall meet one of the following conditions: 1) Be installed in spaces or areas that are fully protected by an approved automatic fire suppression system."

The conduit runs exposed tight to deck, and also through non-sprinklered, non-combustible ceiling cavities.

I'm worried that we'll be required to sprinkler the entire concealed space where there is unprotected conduit installed - or would it be acceptable to provide localized coverage?

Does anyone have experience with this or know of any guidelines for this application?

This is a first for me in my 20-years, historically I've always seen this type of conduit be encased in concrete or handled by one of the other (4) options listed in the NEC.

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NFPA 409, 2016 Edition, Sections 6.2.10 and 7.8 discuss the addition of a 500-gpm allowance for exterior hose.

The standard does not specify a duration, only to fall back on NFPA 13 for calculation purposes.

Without any firm guidance, am I looking at a duration of 90-minutes for Extra Hazard occupancy?

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NFPA 30 Figure 16.2.5 is used to determine if a material is viscous liquid or not.

I am having an issue with a interpretation of the "Weight (percent flammable or combustible liquid)".

Is this weight for the liquid only or the liquid plus the container?

Example: Total package / container weight = 2.48 grams. The liquid inside is a Class III-A mixture that is 0.78 grams (31.5%).

If I go with the entire package Figure 16.2.5 is applicable (less than 50%), but if I am just looking at percent of combustible liquids, all the liquid is combustible.

Thanks in advance. 

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We have a medical marijuana facility with an extraction room that does not story any butane.

The room itself is 750 sqft, and it does not store flammable materials that are used for extraction within the same room. Those will be outside in a locked metal storage shed.

Would the room remain an Ordinary Hazard Group II / Agricultural, or be considered Extra Hazard?

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I'm working with a warehouse owner who has equipment that is on skids, stored onto racks. Each skid is less than 20 square-feet in plan view. This warehouse is only using single-row racks, not particularly high.

I understand 20 sqft to be the maximum threshold for an "open-rack" storage arrangement versus "solid shelves", by the definition of NFPA 13 for solid shelving.

If we maintain flue spaces all around of 6-inches, could the owner theoretically just store each skid at least 6-inches apart, and still not have solid shelf situation?

My gut says that 100-ft long, single row of racks with only this equipment on skids would act more like solid shelves, but if the flues are maintained, then it appears as if NFPA 13 still allows treatment like an open rack. This specific project may be more of a theoretical as the owner has plenty of floor space to limit the overall height of the racks, but I'd appreciate any feedback for future scenarios that come up like this.

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I am designing a sprinkler system for an underground parking garage (Ordinary Hazard, Group I) with NFPA 13 (2013 Edition). The concrete ceiling has slab bands that drop 12-inches (300mm) down from the underside of the ceiling.

I am using extended coverage uprights on a dry system.

Can I use Section 8.8.4.1.2 (1) to show sprinklers 1- to 6-inches below the slab band, which would make them 13- to 18-inches below the underside of the ceiling?

This would make them less than 22-inches below the ceiling.

I'm asking because I don't know if a slab band counts as a "structural member" as far as this is concerned.

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Is Unistrut allowed to be used for trapeze braces on sprinkler systems?

There are two issues at hand - one is making sure the section modulus allows for Unistrut to be used. In this case we have a 16-inch span with only a 2-1/2" main on the trapeze, so we're good there.

The other issue is the listing and approval of components. Any tips here?

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We have a two story apartment building, and we are installing an NFPA 13R wet pipe sprinkler system.

Is an outside hose demand required to be included within the calculations?

There are no inside hose stations.

If outside hose demand is required, is the demand the same as light hazard? 100 gpm?

We couldn't find a reference to this in NFPA 13R.

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What methods do people use to drain a riser that is located in a basement?

We have a four-story building with the sprinkler riser in the basement. The basement consists of a small mechanical room and the rest is earth-filled.

Would it be permitted to run a drain pipe up to the surface, which would drain the majority of the system until the water finds its level, and then provide a secondary 1" drain which would run to a sump pit?

In this particular situation, the remaining water adds up to roughly 20 US gallons. The sump pit is 42 US gallons, and the sump pump is rated for 50 GPM.

Thank you very much!

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I have a building being renovated into a (A-2) restaurant for a total of three floors with a basement level. All levels are classified an A-2 occupancy. The building is going to be sprinklered and have a fire alarm system.

Now that the project is about 75% to completion, the owner has resubmitted plans to have the roof top used as a A-2 also with an occupant load of about 30 people. The ground floor to the roof is 29-ft.

The building is not over 30-ft to require a standpipes, but can it be required now due to the rooftop being used as a occupied floor?

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I have alcoves in a corridor that has a lower ceiling height than the rest of the corridor. The lower ceiling is 36-inches lower than the higher ceiling.

The alcoves are sprinklered, but not the higher ceiling in the corridor directly adjacent to the alcove. The rest of the corridor is sprinklered, spaced off the sprinkler in the alcove.

Can sprinklers be omitted at the higher ceiling?

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What would a proper hazard classification be for a casino gaming floor area?

The project is under NFPA 13, no known insurance requirements.

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Can I install a concentric reducer in the vertical position and a 90 on the suction side of a vertical inline pump?

The feed is coming from above the pump, and we don't have space for a 90 and an eccentric reducer.

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I am an AHJ and have a salt spa in our jurisdiction with sprinklers in the salt therapy room. Not surprisingly these sprinklers are heavily coated with salt deposits.

What is the best type of head to use in this environment?

If we require wax-coated corrosion resistant heads we are still concerned with salt deposit build up.

Any other suggestions on ways to protect heads in this room?

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We have a project with a generator room on the outside of a building. There is a large louvre to an air chamber that is about 8-feet wide before another concrete wall is to be erected. The concrete wall has some bracing back to the main building.

Is there a reason sprinklers should be required in this air chamber that is open to the sky?

I'm looking for code help either way. Thanks in advance.

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13, 13R, 13D: Calculations and High Ceilings

I was reading through NFPA 13 (2016 ed.) and caught Section 8.10.2.2:
Residential Sprinklers shall not be permitted to be used on ceilings with slopes greater than 8 or 12 or ceiling heights greater than 24 feet unless specifically listed for this purpose.

This got me curious about how it affects NFPA 13R and 13D, checking into those I didn't see any restrictions where residential sprinklers stop being allowed at the ceiling height, however the maximum 24-ft ceiling was noted in NFPA 13D (2019) 10.2.1 and NFPA 13R (2019) 7.1.1.3.1 in regards to design sprinklers.

So am I correct in assuming that if you have a residence with a 24'-1" foot ceiling in the family room (say there's a loft second floor), that you now have to calculate and design the space per NFPA 13 rather than 13R or 13D (as that ceiling height is outside of the scope of 13R and 13D)?

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Can someone tell about how often are Fire Department Connections ever used in a real fire?

We all install FDCs but in the real world how much do Fire Departments use them?

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Can a 3-phase, 480 volt electric service inside the fire pump room be reduced down to 208-volt 3-phase with a transformer properly sized for the 6x amps of demand of the the fire pump serving the building?

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NFPA 11 identifies several materials for foam concentrate pipe & valves, including brass, bronze, stainless steel (304 or 316), or other material in accordance with foam concentrate manufacturer's certification of compatibility with the foam concentrate as approved by the AHJ. [NFPA 11-2016 4.7.1.1]

Can we use hot-dipped carbon steel pipe to meet this requirement after the foam pump to the foam chamber of the cone roof tanks?

The distance is more than a mile long (1.2 miles, 2 km). Thanks in advance.

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When are standard response sprinkler heads a better choice than quick or fast response heads (5mm vs. 3mm bulb)?

Are there applications where it would be preferable to have a slower response time?

As far as I know, quick and standard response heads cost the same, come with the same k-factors, and the same temperature ratings.

Why would the slower one be chosen? When would you choose a Tyco TY-B instead of a TY-FRB?

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A typical specification is broken down into 3 parts:
Part 1 – General
Part 2 – Products
Part 3 – Execution

In a typical specification for sprinkler pipe we often see something like this:
Part 2 - Products
2.2 Steel Pipe and Fittings
Schedule 40 Galvanized and Black steel pipe
Schedule 10 Black steel in pipe NPS 2.5 and larger

Part 3 - Execution
3.12 Piping Schedule
NPS 2 and smaller - Schedule 40 black steel
NPS 2-1/2 and larger - Schedule 40 black steel

When Part 2 and Part 3 of the same spec contradict one another, which part rules?

I know the answer is to write an RFI, but we often don’t get an answer prior to bid time.

Also, what is the thought process of the EOR for providing a spec like this in a bid document to begin with?

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When coming out of a pump room with underground feed which then connects to an underground loop with a bullhead tee, are isolation valves required on the bullhead tee?

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NFPA 13 provides allowed omissions for sprinklers in combustible concealed spaces where the entire cavity is filled "with non-combustible insulation". 

Is fiberglass the only non-combustible insulation? Is blown-in insulation considered to be non-combustible, or does it depend on the type of blown-in?

Just curious if there was helpful literature so that we knew what to recommend or look for when we come across these scenarios. Thanks in advance.

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When we run hydrant flow tests, we usually use both 2-1/2" side-outlets of a typical dry fire hydrant. We hook up one, threaded, swivel 45-elbow on each side to divert water in a direction that won't destroy anything.

What is the appropriate Coefficient of Discharge when measuring the pitot on the centerline of the elbow?

Traditionally flowing straight out of the side outlet of a hydrant, NFPA 291 gives three Coefficients (0.90, 0.80, and 0.70) based on how the outlet projects into the barrel. NFPA 291 also states that a coefficient of 0.85 is suggested for stream straighteners, unless the coefficient of the tube is known.

Is there a known Coefficient for a single 45-degree elbow?

Any help is greatly appreciated.

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