Water Hammer Arrestors

[glkearns]

I had a close call on a job that I just finished, Horrible water hammer from the Master bathtub fill valves. I was able to install some inline hammer arrestors to solve the problem(through access hole) without destroying finishes. The question that I am pondering is:

Should I have some sort of water hammer arrestor allowance(those things aren't cheap) and if they don't go with it, then have them sign some sort of statement saying they didn't want to pay the extra $ for the hammer arrestors so the correction of the problem is cost of the owner(or something like that?)

I am very lucky that this didnt turn into a real mess. Anyone install these on all fixtures(or on fixtures you know are going to be quick closing valves?) Have any of you run into this problem?

This is the first time I have gotten to the finish on a project and had to deal with banging pipes. I tend to over strap everything.


Greg

[ToUtahNow]

I had a close call on a job that I just finished, Horrible water hammer from the Master bathtub fill valves. I was able to install some inline hammer arrestors to solve the problem(through access hole) without destroying finishes. The question that I am pondering is:

Should I have some sort of water hammer arrestor allowance(those things aren't cheap) and if they don't go with it, then have them sign some sort of statement saying they didn't want to pay the extra $ for the hammer arrestors so the correction of the problem is cost of the owner(or something like that?)

I am very lucky that this didnt turn into a real mess. Anyone install these on all fixtures(or on fixtures you know are going to be quick closing valves?) Have any of you run into this problem?

This is the first time I have gotten to the finish on a project and had to deal with banging pipes. I tend to over strap everything.


Greg

I think ther real question is what did you miss which allowed the hammer?

Mark

[glkearns]

What are my options? You think it's a missing strap? Or I missed some other condition or part? Like I said this is the first time I have had this issue.

Greg

[toolaholic]

In S.F. they are in the ammendment to the UPC. You won't pass without them!

12" on 1/2" 18" high for 3/4" pipe

[glkearns]

In S.F. they are in the ammendment to the UPC. You won't pass without them!

12" on 1/2" 18" high for 3/4" pipe

Yes they are, do you know if the mechanical ones can be used instead of an air chamber?
Greg

[ToUtahNow]

Greg,

My guess is you missed a strap somewhere. The other option is the valve is just so fast acting that no matter what you do you will have a hammer. In the second scenario refer to UPC Section 609.10 which says if you have fast acting valves which might cause a hammer you have to install approved mechanical devises to prevent it.

Mark

[JCsPlumbing]

Haven't ran into too many scenarios where it couldn't be corrected pretty easily.

We don't require them. But install if necessary. I've always been told a made "airchamber" wasn't worth a darn. Becomes waterlogged pretty quick and must be drained down. :rolleyes:

I've had good success with models by Sioux Chief. You can install them near the problem valve with success also. Ex. Shower valve that's easy to quickly close-put them under the sink and it can correct the problem.

Two questions.

1) All copper?

2) Expansion tank installed?

J.C.

[glkearns]

All copper(aside from one 1/2" hosebibb line behind some $$ (original) built in cabinets.

No expansion tank, open system.

[JCsPlumbing]

Do you solder the pipe to your hangers? I've heard debates both ways and just curious. Anyway...

An expansion tank will often eliminate this in my experience also. If it's on a well the bladder tank can absorb some too.

But if you're putting in air chambers I like the variety Sioux Chief makes.

J.C.

(Still hope you get that tub fixed. :joyful:)

[glkearns]

Do you solder the pipe to your hangers? I've heard debates both ways and just curious. Anyway...

An expansion tank will often eliminate this in my experience also. If it's on a well the bladder tank can absorb some too.

But if you're putting in air chambers I like the variety Sioux Chief makes.

J.C.

(Still hope you get that tub fixed. :joyful:)
I used the Mifab 3/4 ips hammer arrestors and fixed the prob. I thought about installing a expansion tank, but really had no where to put it. The rinnai is an exterior unit w/recess kit. My tub on the other hand, if I don't hear from them by Tues next week, I will call them.
Greg

[drtyhands]

What's the structures pressure.Sometimes things will bang around before we install the pressure requlator.

[Killertoiletspider]

I put an air chamber on every opening in the water system. That is code here.

[drtyhands]

I put an air chamber on every opening in the water system. That is code here.
We are UPC we aren't required to put them on everything yet.
I would not like to lose a job because I included the cost of arresting every stub-out.
Only City of Los Angeles enforces hammer arresters on quick closing valves.Haven't even seen them enforce the ice makers yet.

[JCsPlumbing]

Adam, does this feel like code redundancy to you?

J.C.

[drtyhands]

Adam, does this feel like code redundancy to you?

J.C.
Which or both jurisdictions are you refering to.Are you refering to the expansion tank with the hammer arrestors.I would think the arrestors would still be needed at the higher volume quick closing fixtures.
Besides,it don't do me no good to question My code on a project by project basis.Utah has told me on a few occassions to "quit crying,just do what the law requires and write your lawmakers if you want it changed".He did I swear:p

I was actually throwing a tissy when Mark/Utah informed me that I had been squeaking by not puting them on quick closers and not getting called on it.Everyone I see installing is blowing it off,so I was pissed I have to budget for it and still get the job to maintain zero guilt factor.

[glkearns]

What's the structures pressure.Sometimes things will bang around before we install the pressure requlator.

60 psi, that was my first thought too

[glkearns]

Washing machines and ice makers are enforcable here, and at one supplier they aren't even carrying the recess boxes without them.

Other cities, could care less.

Greg

[JCsPlumbing]

I know what you're saying. Utah is right to a degree. But alot of us don't think about is that the codes are controlled by the Dept. of Insurance. At least in N.C.
Anyone reading this please don't try and educate me about the ICC, UPC, IPC as I'm informed on them and there staff.

But insurance has alot of bearing on the codes and they will do anything to "improve" upon it to decrease payout.

They're statistical fanatics. One day we might install Type K water lines. Brazed joints. 20 or 30 Hammer Arrestors. Water detecting solenoids in all fixture rooms. :rolleyes:

Anyway...

J.C.

[DuckButter]

We put air chambers on laundries & shower valves by code.
I've tried Amtrols "Mini-trol" and they work great..a bit more bulky than a shock absorber or airchamber, but I like them.

[JCsPlumbing]

Metallic supply pipe. Water hammer arrestors enforced here. Everywhere.

J.C.

[drtyhands]

We put air chambers on laundries & shower valves by code.
I've tried Amtrols "Mini-trol" and they work great..a bit more bulky than a shock absorber or airchamber, but I like them.

Showers? How do you access them?

What about flushometers?

[glkearns]

Metallic supply pipe. Water hammer arrestors enforced here. Everywhere.

J.C.

Mechanical arrestors, or air chambers?
Greg

[drtyhands]

I thought air chambers gathered bacteria.Knowledgeable inspectors have made us remove nipples and caps to spout on a tub/shower to shower conversion and requested a plug for this reason.

[JCsPlumbing]

Mechanical arrestors, or air chambers?
Greg

Piston type mechanical arrestors. I have no idea why site built air chambers would be required or allowed.

J.C.

[glkearns]

Piston type mechanical arrestors. I have no idea why site built air chambers would be required or allowed.

J.C.


San Francisco requires them, I agree with you though, air chambers are minimally effective at best.

Greg

[Killertoiletspider]

San Francisco requires them, I agree with you though, air chambers are minimally effective at best.

Greg

We've been installing them in high rises for 90 years, with no problems, and some of these buildings have over 100 PSI water pressure on the lower floors.

[drtyhands]

San Francisco requires them, I agree with you though, air chambers are minimally effective at best.

Greg
Got a buddy that renovates apartments up there.I was surprised when he told me of this.

[JCsPlumbing]

We've been installing them in high rises for 90 years, with no problems, and some of these buildings have over 100 PSI water pressure on the lower floors.

No disrespect, but that does not mean they are still working in any way. The buildings pipes may not show hydraulic shock at all even without them.

Cut one open at the top floor, betcha' it's full to the top with water. Am I completely off here Spider? I have not done this myself. Just stating what I've been told and I understand the theories & practice.

J.C.

[Killertoiletspider]

No disrespect, but that does not mean they are still working in any way. The buildings pipes may not show hydraulic shock at all even without them.

Cut one open at the top floor, betcha' it's full to the top with water. Am I completely off here Spider? I have not done this myself. Just stating what I've been told and I understand the theories & practice.

J.C.


High rises aren't piped up, they are piped down. City water gets pumped to the penthouse, and looped around for all the risers there, which are then downfed back to the basement. Newer, taller buildings will usually have two zones, a high side and a low side, if it is an 80 story building the will pipe the lowside to the fortieth floor, and then down, and the highside to the penthouse and down to the 41st floor.

Any branches off the risers will drain every time that branch is shut down,drained, and when it is turned back on, the air cushion is re-established. Pretty simple stuff, no rocket surgery required, and lot less expensive than mechanical arrestors that are subject to failure.

[SlimTim]

We use the IPC 2003 and simple air chambers are not approved. (604.9)

[Plumbus]

I'm surprised they don't require one for irrigation solenoid valves. They make a big band in my house.:)
When I have an occasional hammer problem, I usually try to fix the problem, but if I can't find it, I have resorted to treating the symptom with a hammer arrestor. As for San Francisco, when using air chambers, I believe they require an access panel and a bleeder valve for recharging.

[DuckButter]

Showers? How do you access them?

What about flushometers?
YES!
On commercial batteries where multiple flushometers would be installed, we do.
Our code specificies they are to be installed on any fast acting valve.
We usually install them residentially on laundries & shower valves.
Our code requires they be 3/4" and be at least 16"-18" long.

[drtyhands]

We've been installing them in high rises for 90 years, with no problems, and some of these buildings have over 100 PSI water pressure on the lower floors.
That's what I say.;):D

[DuckButter]

Oh, Adam...I don't install the mini-trol in enclosed spaces.
They come in handy on toilets under the basement ceiling or under vanities or KS's.

[glkearns]

As for San Francisco, when using air chambers, I believe they require an access panel and a bleeder valve for recharging.


Last time I worked there, no access panel required, and no bleed down valve per say required. Just a 12"(on 1/2") or an 18" (3/4") air chamber just before the connection to the fixture. So on a shower valve, lets say, there would be no real drain down once it fills up.

Greg

[Killertoiletspider]

Last time I worked there, no access panel required, and no bleed down valve per say required. Just a 12"(on 1/2") or an 18" (3/4") air chamber just before the connection to the fixture. So on a shower valve, lets say, there would be no real drain down once it fills up.

Greg

Shutting the riser off and opening all the fixtures would drain them down just fine, gravity always wins.

[glkearns]

Shutting the riser off and opening all the fixtures would drain them down just fine, gravity always wins.

Ground floor shower, piped from above, water trapped at valve level no where to go. Most of the time the drain down does work. I had a astronomy professor who's token phrase was. "Gravity is Boss."

Greg

[Killertoiletspider]

Ground floor shower, piped from above, water trapped at valve level no where to go. Most of the time the drain down does work. I had a astronomy professor who's token phrase was. "Gravity is Boss."

Greg

Think outside the box, pull the the valve stems.


My philosophy professor always told me gravity sucks.

[SlimTim]

I'm surprised they don't require one for irrigation solenoid valves. They make a big band in my house.:)
When I have an occasional hammer problem, I usually try to fix the problem, but if I can't find it, I have resorted to treating the symptom with a hammer arrestor. As for San Francisco, when using air chambers, I believe they require an access panel and a bleeder valve for recharging.

Don't you have an r.p. on your irrigation system?

[Bob D.]

"An expansion tank will often eliminate this in my experience also. If it's on a well the bladder tank can absorb some too. "

Both these components are upstream of the point where the water hammer occurs so will do little to arrest the problem.

"A physical body will remain at rest, or continue to move at a constant velocity (http://en.wikipedia.org/wiki/Velocity) along a straight path, unless an external net force (http://en.wikipedia.org/wiki/Net_force) acts upon it." Newton 1687.

The water will want to move in that straight path unless acted upon by some external force, which in the case of plumbing is a fitting which changes the direction of water flow. A long run which dead-ends into a T or 90 or a quick-acting valve ends up absorbing all that force. The placement of anchor points and shock arrestors can not be done haphazardly and expect the problem to be eliminated, it could be made worse.

If your code requires shock arrestors (WHAs) then you should be including them in your bid, not begging to have their costs covered later on. If you feel that this added material cost may cause you to lose the job then point out that you have included the cost of WHAs and their installation in your bid as required by code. For other bids to be compared to yours equitably, they should also include (or be adjusted to include) the WHAs or maybe technically they should be rejected as non-responsive bids since they don't conform to to code requirements.

You are responsible for supplying all the materials to install the system to code right? If the A/E misses a code required item who is gonna get called on it...YOU the plumber will. Why, because of the catch all cover their a** clause that the A/E always puts in the specs stating the contractor is responsible for ensuring the installation is to code. Your license also states that you must install per code.

Down the road you could be held liable for damages or injuries caused by improperly installed piping. This happened in a hotel where the hot water line was not properly supported and WHAs were not placed per the drawings. Years later the HW line blew apart (failed joint at a 90), hot water rained down on hotel guests and scalded a number of them.

Analyze the placement of your WHAs and position them so they absorb the majority of the force. This may mean adding a tee and installing the WHA on the end of the run and the supply to the fixture being fed off the branch of the tee.

[JCsPlumbing]

Ground floor shower, piped from above, water trapped at valve level no where to go. Most of the time the drain down does work. I had a astronomy professor who's token phrase was. "Gravity is Boss."

Greg

How often is this draindown maintenance needed on a residential application? I think I understand Spiders reasoning and proof in commercial. But for residential:

How many times are you called to do a draindown for a customer? You know they don't know what to do about it. :rolleyes:
If very little, then aren't they becoming waterlogged, no banging pipes, and probably unnecessary?
If very often, then isn't it overmaintenance that could be eliminated with piston type mechanical ones?

Don't want a debate. Just the best way to do things based on everyones experience. I have some customers that have had the piston type in for 5+ years with no callbacks for banging pipes or to maintain/replace them OR for any draindown.

Thanks.

J.C.

[Bob D.]

Piston type mechanical arrestors. I have no idea why site built air chambers would be required or allowed.

J.C.

Because before mechanical arrestors existed this is how the problem was dealt with. One would think they would have been removed from new construction now that mechanical arrestors have been available for over 25 years.

[JCsPlumbing]

Because before mechanical arrestors existed this is how the problem was dealt with. One would think they would have been removed from new construction now that mechanical arrestors have been available for over 25 years.

That's what I meant. I don't know why they would be required or allowed today.

Spider makes a good case on the commercial side. But I do think with proper engineering the draindown maintenance could be eliminated.

J.C.

[drtyhands]

I like what I've heard so far.Especially about the lawmakers listening to lobbying insurance companies.

We have a code.I try to follow it best I can because it makes things easier in the long run.I don't like spending time trying to figure out what's necessary.

Some guys have said they put them on everything(damn near) in order to provide a complete product.I've overseen the completed thousands of water systems containing tens of thousands terminations,some quick closing,most not(obviously).The plumbing is secured properly.There are no problems,period.Although I haven't been doing this for 90 years I think 25 ought to be a good enough track record.

Adam

[Bogart]

The only time I have run into water hammer is when the pipe size is too small and the velocity increases. The Illinois code causes water hammer by allowing undersized pipe. I never run 1/2" in a house except to sillcocks, and the last fixture.

[boillerman]

I don't even think we can install laundry boxes that don't have arrestors in the box with the valve anymore here. I've run into it a few times a year, but I usually find that the end of a longer run of straight pipe on a main in a basement (hopefully accessable) is a good place to stick a 3/4 bumper and quiet down D/W's, stools, whatever else. The old drain down type, as mentioned earlier in this thread, homeowners have to be educated about every few years if they have them. I had one recently that had me go ahead and put in mech ones so he didn't have to mess with the drain down anymore.