You are hanging pipe and you need to install a trapeze hanger on a retrofit project (no seismic requirements). 


One joist/beam is above and the 2nd is on the other side of a full height wall. Can you penetrate that wall, with your trapeze, to hang off the other beam?

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I had always thought that couplings didn't need to be calculated under NFPA 13, but I'm reviewing a set of calculations which show 1-foot of schedule 40 equivalent for each coupling. This is for a 4-inch main with roll-groove couplings. Any ideas?

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Does anyone else know of other one-piece stainless steel risers besides those made by AMES?

At my company we seem to be experiencing issues with some that are not made in America. Besides AMES, I'm not sure who else makes them.

For the sprinkler installers out there, do you prefer installing these components rather than a traditional riser stub out from the ground into the building?

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There's a varying degree of specifications out there - but I've never really seen it openly discussed or defended.

Some organizations (such as military, many healthcare clients) require schedule 40 for pipe 1 through 2 inches in diameter. Some engineers hardly compile specifications and place no requirements on the pipe thickness. Some projects only allow schedule 40 or even schedule 80.

If you're an engineer, what is your basis for recommending different pipe thicknesses for different clients? Is corrosion the only reason why the thicker pipe diameter is specified for your clients? 

Would be really interested in understanding the reasoning (one way or another) for specifying different pipe thicknesses on suppression systems. Thanks in advance.

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Solution | Posted 09/10/19

​In-Rack Sprinkler System Control Valve Arrangement:

Concerning the valve arrangement shown in Figure 7.8.2.8.4 (NFPA 13 - 2016): (One preaction valve is used for both ceiling and in-rack sprinklers protecting the same area)

In-Rack Sprinkler System Control Valves section in NFPA 13 requires that separate indicating control valves and drains shall be provided and arranged so that ceiling and in-rack sprinkler systems can be controlled independently.

Assuming separate detection systems for ceiling sprinkler systems and in-rack sprinkler systems:
Is the separate check valve in the Figure 7.8.2.8.4 for ceiling & in-rack required for a single interlock preaction system? Could it be removed?

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Many two-inlet (2 x 2-1/2") fire department connections I'm familiar with and commonly have a single-clapper, where the clapper will swing and cover the inside of the inlet on the side of the FDC not being used to prevent flow out of the other inlet.

Is there any advantage to having a double clapper?

One disadvantage I see is that you can't forward-flow test the backflow preventer out the FDC if there are clappers for each inlet.

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How does AutoSPRINK compare with HydraList for stocklisting? I know many local fabricators are familiar with the HydraList files and I've used the program for years now, but I've also heard good things about AutoSPRINK - just wanted to know how the two compare from users on the stocklisting side of things.

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Does the proximity to a residence and the number of windows make a difference in which system is used (NFPA 13 vs 13R vs 13D)?

​What are those requirements that make it change?

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Solution | Posted 09/04/19

​​Annual inspection of wet barrel hydrants must include all of the following except:
a. verify marking of hydrant
b. verify outlet thread condition
c. verify access to hydrant
d. verify cracks in hydrant barrel

Solution | Posted 08/30/19

​Determine the flow (in gpm) through a residential sidewall K4.2 sprinkler at 10.1 psi.
a. 13 gpm
b. 18 gpm
c. 21 gpm
d. 42 gpm

Solution | Posted 08/29/19

When there's a cloud ceiling that requires sprinklers above and below, how does that play out in the hydraulic calculations? NFPA 13 23.4.4.5 implies that we should only include the upright heads at the ceiling and exclude the pendants in the floating clouds from the remote area calculations. Do you think that's the right call?

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Solution | Posted 08/28/19

I have a warehouse with a roof 20 feet above. The designer has branch lines hanging under the ceiling joists. He has 10 foot drops of 1-1/2" sched 40 to an ACT ceiling over office spaces. We are in a "D" seismic design category building. I am unable to find any requirements for vertical restraint in the NFPA 13 or ASCE 7-10. Can anyone direct me? 

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Solution | Posted 08/26/19

Does a hydrostatic test need to be performed for a project that just has relocated sprinklers, or just a leakage test subject to working pressure?

I'm having trouble finding where NFPA 13 gives guidance on this. Any help is appreciated.

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Solution | Posted 08/23/19

In NFPA 13 under "Location of Hangers on Branch Lines", Section 9.2.3.6 (2016 Edition) states that "wall-mounted sidewall sprinklers shall be restrained to prevent movement."

This section does not relate to seismic restraint, and annex material clarifies as much.

How is this sidewall-restraint typically achieved? 

Many sidewall sprinkler installations have an armover and a drop that goes down the wall before a reducing elbow serves the sprinkler in the wall, and I don't recall ever seeing a means to restrain the pipe (or sprinkler) for steel jobs.

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Do you have any thoughts or input on the interior exit stair penetration limitations of Section 1023.5 of the IBC? 

I have someone contending that you aren’t allowed to run a “bulk feed” main into a stairtower and then back out again on a different level.  They claim that 1023.5 limits penetrations only to MEP equipment that serves the stairwell itself.  I contend that, especially as clarified in the 2018 edition (although I contend that it was always the intent), any fire protection system is allowed to penetrate such a stairtower as needed, as long as the penetrations are correctly firestopped etc…
 
The confusion comes from the 2015 edition, which reads (emphasis added to indicate the confusion that I think this person is having):

“Penetrations into or through interior exit stairways and ramps are prohibited except for equipment and ductwork necessary for independent ventilation or pressurization, sprinkler piping, standpipes, electrical raceway for fire department communication systems and electrical race-way serving the interior exit stairway and ramp and terminating at a steel box not exceeding 16 square inches.  Such penetrations shall be protected in accordance with Section 714.  There shall not be penetrations or communication openings, whether protected or not, between adjacent interior exit stairways and ramps.”
 
I believe that that person is seeing that “serving the interior exit stairway and ramp” portion of that snippet, and they are applying it to everything.  However, I contend that that is actually applying specifically to “…and electrical race-way serving the interior exit stairway and ramp and terminating at a steel box not exceeding 16 square inches”.  I think that the person is cherry picking what they want it to say, although it is somewhat confusing the way it’s all written on one line.  I believe that if that person really wanted to apply this verbatim, then you would not even be allowed to have combined standpipes that feed sprinkler systems outside the stairwell, or even dedicated sprinkler risers in the stairwell wouldn’t be allowed to serve any floor area outside the stairwell.  Basically any sprinkler riser in a stairwell would only be allowed to feed that specific stairwell…  I think it’s clear that this is not the intent of the code.

Read More Here

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NFPA 13 Section 8.15.4 (2013 Edition) requires certain types of unenclosed floor openings to be protected with closely spaced sprinklers where sprinklers serve as an alternative to the enclosure of the vertical opening. 

What method do you use to determine if the opening requires enclosure, and thus closely-spaced sprinklers? 

As a sprinkler designer, I may overlook something in the Building Code that allows the unprotected opening, or vice versa.

A pre-bid RFI to the architect seems to be the best course, but it would be nice to have something to hang the hat on before the bid is submitted.

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I've heard from several installers that small diameter schedule 10 pipe (such as 1-1/4") will warp if there's more than two welded outlets made onto it.

Would any installer/contractors weigh in on how you best combat this problem?

I could see larger diameter (1-1/2" or more) schedule 10 as a possible solution, which also helps hydraulics. I could also see voluntarily going to schedule 40 as a possible solution. Cutting the pipe into shorter segments and adding couplings would also help, but I could see the cost adding up for the labor, couplings, and additional hangers.

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Solution | Posted 08/19/19

My son has purchased a condo, (prior apt conversion). They removed the closet doors in the living room related to an air flow vent return on one side when the central air was added.

There is a sprinkler in the center of the former closet. I was told I can not enclose the sprinkler in a closet when I wanted to build the closet doors 3/4 of the way, (leaving 35 inches for the air flow vent). So, now the closet would be only 40" wide. Do you know in MN if I can enclose the sprinkler? Thank you.

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Once again great info/insight. Though it made me think.

What if you have a type II hood without wet chem protection? Are sprinklers required? I think yes (following obstruction rules).

To take it a step further, what if you have a type I hood with protection over the required appliances including the plenum but not below the plenum in areas where there are ovens/non-cooking equipment? As an AHJ, I have never required additional protection here. But now I question myself.

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