Plumbers - building code question, sprinkler pipes

[Triplegreen500]

So, at work, we have a 2" water feed line that runs the length of our performance room (I work in a live music venue). Figure...a 100' run. There are (4) 90 degree bends in the pipe, to clear what used to be a roll-up garage door - instead of going straight, it comes in, turns left; turns right; turns right; then a final left to get back into the original line. Those bends/angles are, I suspect, what's enabling the pipe to move.

Every time someone flushes a toilet, that line moves laterally. A LOT. Enough so that I worry about long-term fatigue to the pipe, the couplers, and the all-thread hangars.

It is run parallel to a 4" or 5" cast iron sprinkler pipe. Figure....about 8" apart. I'd have to measure to be sure.

What I (and my boss) would like to do, is horizontally-brace the water line, to the sprinkler pipe, to help quell the horizontal shifting when water pressure changes. I will use the correct ferrous clamps, with all-thread between them, to perform horizontal bracing but no support loading. Both pipes are fully independently supported - by clamps and all-thread - directly to the building structure (ceiling joists). I can't imagine that beefy cast-iron sprinkler pipe would be subject to the kind of deflection the smaller water pipe is, but I'll give it a couple good pushes first just to be sure.

We're open. Inspections are completed. However, these are visible systems and anyone could look up and see these braces.

I've been digging through the NFPA and can only find references to lateral loading for areas subject to seismic activity (this is MD, we are not in an earthquake zone). It says I can't have the sprinkler pipes encumber the LOAD of another system...but I can't find anything about whether or not I can laterally brace off of it.

Plumbers - what say you?

 

[Fran Blacker]

@moparedtn

 

[PlymCrazy]

Whatever you do, don't hang ANYTHING from the sprinkler pipe. Especially if it will be visible during any following inspection. An observant and thorough inspector could cite you for it.

NFPA 13-9.1.1.8.1 states "Sprinkler piping or hangers shall not be used to support non-system components."

(Just FYI, sprinkler pipes are typically steel, not cast)

I'll let a plumber chime in on horizontally bracing or some remedy for that pipe jostling you have occurring.

 

[Triplegreen500]

There would be no vertical/weight support. Only lateral stability.

 

[T2R9]

I would use earthquake lateral bracing. One at each 90 should do the trick. Any beams nearby to brace to?

 

[Triplegreen500]

Nope.

All the pipes are about 2' below the ceiling joists. One section is about 4' from an exterior wall, but not enough to stabilize the entire run.

 

[YY1]

Install a "water hammer"?

 

[PlymCrazy]

If I'm understanding your description accurately, and it was my place, this is what I'd do...
I'd stabilize the lateral at one wall using something like unistrut.
I'd then stabilize the offset as close to the elbows connected to the main run as possible.
Minimal time and supplies to do this and you can assess further as necessary after that's done.

Here's a rough sketch of my thoughts….

 

[YY1]

You know what a water hammer is, right?

It's an empty pipe extension, above the incoming plumbing.

It acts as a place for air and pressure to temporarily escape, and helps prevent the pipes from "hammering".

 

[j-c-c-62]

I agree. That solves the problem to a large degree, instead of treating the symptom.
Might be best to install more than one, at or near ends of lines or near elbows depending direction of water flow.
From a liability standpoint, I wouldn't touch an inspected fire sprinkler plumbing system in a public space even if my whole family were lawyers.

 

[PlymCrazy]

Does it behave like this with every toilet? Or is there just one that is culprit? If you can narrow it down to one, it may be as simple as swapping the flush valve to a slower closing one.

 

[moparedtn]

So, at work, we have a 2" water feed line that runs the length of our performance room (I work in a live music venue). Figure...a 100' run. There are (4) 90 degree bends in the pipe, to clear what used to be a roll-up garage door - instead of going straight, it comes in, turns left; turns right; turns right; then a final left to get back into the original line. Those bends/angles are, I suspect, what's enabling the pipe to move.

Every time someone flushes a toilet, that line moves laterally. A LOT. Enough so that I worry about long-term fatigue to the pipe, the couplers, and the all-thread hangars.

It is run parallel to a 4" or 5" cast iron sprinkler pipe. Figure....about 8" apart. I'd have to measure to be sure.

What I (and my boss) would like to do, is horizontally-brace the water line, to the sprinkler pipe, to help quell the horizontal shifting when water pressure changes. I will use the correct ferrous clamps, with all-thread between them, to perform horizontal bracing but no support loading. Both pipes are fully independently supported - by clamps and all-thread - directly to the building structure (ceiling joists). I can't imagine that beefy cast-iron sprinkler pipe would be subject to the kind of deflection the smaller water pipe is, but I'll give it a couple good pushes first just to be sure.

We're open. Inspections are completed. However, these are visible systems and anyone could look up and see these braces.

I've been digging through the NFPA and can only find references to lateral loading for areas subject to seismic activity (this is MD, we are not in an earthquake zone). It says I can't have the sprinkler pipes encumber the LOAD of another system...but I can't find anything about whether or not I can laterally brace off of it.

Plumbers - what say you?

That's not a plumbing question, that's a fire protection/life safety question.
NFPA is the correct Code to reference, in your case NFPA13 - which states that nothing can be suspended or
otherwise attached to fire sprinkler piping other than its' own suspension components.
By the way, sprinkler piping isn't cast iron - it's steel, either black steel or galvanized (exception: some Listed
residential installations are allowed to use orange poly vinyl fire-rated plastic piping and fittings).
The FITTINGS are often cast iron (threaded or grooved, plain end or otherwise).

It's up to you whether to remain in compliance with NFPA Code, of course....if you catch my drift.

 

[moparedtn]

I agree. That solves the problem to a large degree, instead of treating the symptom.
Might be best to install more than one, at or near ends of lines or near elbows depending direction of water flow.
From a liability standpoint, I wouldn't touch an inspected fire sprinkler plumbing system in a public space even if my whole family were lawyers.

Wise man. The liabilities are HUGE these days for messing with any of the various Life Safety components in a building.

 

[Under Pressure]

Look into water hammer arresters w/piston in 2” (Watts brand)
Depending on the fixture count you will most likely need more than one per manufacturer sizing spec/chart.
Previous members comments are absolutely correct, nothing can attach to fire suppression lines.
Fire marshals have been known to cite for banners hanging from sprinkler lines.

 

[moparedtn]

Look into water hammer arresters w/piston in 2” (Watts brand)
Depending on the fixture count you will most likely need more than one per manufacturer sizing spec/chart.
Previous members comments are absolutely correct, nothing can attach to fire suppression lines.
Fire marshals have been known to cite for banners hanging from sprinkler lines.

They'd be correct in doing so - that is exactly what is in the Code.
I've written systems up for that many a time over the decades when inspecting them....and I've seen
some real doozies hanging from lines, trust me.

 

[Under Pressure]

Can’t get any better info than from Ed in Fire and Bill the plumber
Lol

 

[Triplegreen500]

All great information, and exactly what I was looking for. Thank you all.

I know codes are a bitch, and I don't want to run afoul of the City, since many Aldermen, budget officials, inspectors, and elected folk are strong patrons of ours (we're the only actual "music venue" in town, and we're drawing them ALL).

I saw in NFPA that nothing could be "supported" by the sprinkler pipe (which is black steel - I assumed cast iron but it makes sense that they use a newer material now, it's black pipe with red flange connectors), but never found anything about "bracing" or "stabilizing". "Nothing touches it" is a good rule to work with, though!

PlymCrazy - your idea of finishing the "box" is excellent. The span may be too much for allthread - it will sag, the gap is about 12' - but I will look into ways/materials to do that to try and isolate things a bit better. Perhaps short allthread ends, attached to unistrut hanging from the rafters...or "too-long" piece of unistrut laying on, and clamped to, the pipe at both ends, and supported by the rafters. I'll fiddle and measure and stuff, see what will work best for that. I'm also going to look into doing a "V" type support - based on clearances, of course - from the water pipe to the ceiling braces. If I space them properly and have enough, they should be able to stabilize things.

I'll also have the plumber look into a water hammer setup. We were trying to do it all in-house since contractors are a bitch to get hold of these days for some reason....but if the bracing doesn't do it, at least we can get on the books for an install down the road sometime. But ****, if we can get him in for that, we may as well elimnate the "box" turns altogether since the garage door that required it in the first place, is no longer there, and just turn it into a straight run!

This is a single pipe that feeds two audience restrooms. I know the mens is 3 thrones, 4 urinals, and 4 sinks; not sure whats in the ladies room (since I know which room to use....lol), but I may check it out off-hours just for educational reasons. But it is not "a" fixture; it's anytime anyone flushes.

 

[j-c-c-62]

Just removing the "Box" will actually increase the water hammer force, just move it somewhere else and be maybe more problematic.

 

[Triplegreen500]

Just removing the "Box" will actually increase the water hammer force, just move it somewhere else and be maybe more problematic.

I'd think removing the box would make the pipe only likely to move in one plane, since it wouldn't be able to move in-and-out along its length without those corners.

Regardless, I'll try and sell the boss on having the plumber do two things while the system is opened up - remove the box, and install the hammer fixtures.

My main concern (aside from the fact it freaks the **** out of our audience, lol) is that these pipes, and one side of the box (including (2) 90's) are directly over top of my control booth. Sound board, lighting control console....agua no bueno, if those pipes leak or burst, we're (no pun) dead in the water.

 

[Richard Cranium]