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Pressure testing plastic pipe

conarb

conarb

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Joined
Oct 22, 2009
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California East Bay Area
On the old Bulletin Board there was a discussion about fire sprinklers that involved not being able to pressure test plastic pipe. The subject has come up about air testing ABS, not being a plumber can plastic DWV pipe be air tested? I've never seen ABS air tested, all I see air tested are gas lines, but is there a code section referencing it?
 
Re: Pressure testing plastic pipe

I found it in the IBC, that about the IRC?

2007 CPC said:
712.1 Media. The piping of the plumbing, drainage, and venting systems shall be tested with water or air except that plastic pipe shall not be tested with air.
Click to expand...
 
Re: Pressure testing plastic pipe

The issue here is that the DWV industry warns against testing with air. When PVC fails from air pressure testing, it fails catestrophically, not just a simple crack. Water testing is a better method as the water molecules are smaller than air molecules. The problem is that during construction, water is not always an easy option, especially during the winter months and before water is available at the site. Not to mention ensuring that there is a minimum 10' water column for head pressure.

The 2006 IPC recognizes this problem.

This is from Charlotte Pipe:

Use of compressed air or gas in PVC/ABS/CPVC pipe or fittings can result in explosive failures and cause serious injury or death. An air test is not conclusive. Changes in ambient air temperature will cause the air pressure inside the system to vary. If the outside temperature increases, the test pressure inside the system will decrease. This air temperature variance can mask a leak or fail a system that should pass. Finally, leaks are easier to find with a hydrostatic test.
 
Re: Pressure testing plastic pipe

conarb - Without digging into the I-Codes (I'll let the rest of the folks do that) here are the relevant NYS Plumbing Code excerpts...

312.1 Required tests and inspections. Testing and inspection shall comply with Section 312.1 and Section 312.2. (I believe that's a typo and should read 312.2 and 312.3)

312.2 Drainage and vent water test. A water test shall be applied to the drainage system either in its entirety or in sections. If applied to the entire system, all openings in the piping shall be tightly closed, except the highest opening, and the system shall be filled with water to the point of overflow. If the system is tested in sections, each opening shall be tightly plugged except the highest openings of the section under test, and each section shall be filled with water, but no section shall be tested with less than a 10-foot (3048 mm) head of water. In testing successive sections, at least the upper 10 feet (3048 mm) of the next preceding section shall be tested so that no joint or pipe in the building, except the uppermost 10 feet (3048 mm) of the system, shall have been submitted to a test of less than a 10-foot (3048 mm) head of water. This pressure shall be held for at least 15 minutes before the start of the test. The system shall then be tight at all points.

(Here's why I think it's a typo)

312.3 Drainage and vent air test. An air test shall be made by forcing air into the system until there is a uniform gauge pressure of 5 psi (34.5 kPa) or sufficient to balance a 10-inch (254 mm) column of mercury. This pressure shall be held for a test period of at least 15 minutes. Any adjustments to the test pressure required because of changes in ambient temperature or the seating of gaskets shall be made prior to the beginning of the test period.

And the NYS Res Code:

P2503.4 DWV systems testing. Rough and finished plumbing installations shall be tested in accordance with Sections P2503.4.1 and P2503.4.2.

P2503.4.1 Rough plumbing. DWV systems shall be tested on completion of the rough piping installation by water or air with no evidence of leakage. Either test shall be applied to the drainage system in its entirety or in sections after rough piping has been installed, as follows:

1. Water test. Each section shall be filled with water to a point not less than 10 feet (3048 mm) above the highest fitting connection in that section, or to the highest point in the completed system. Water shall be held in the section under test for a period of 15 minutes. The system shall prove leak free by visual inspection.

2. Air test. The portion under test shall be maintained at a gauge pressure of 5 pounds per square inch (psi) (34 kPa) or 10 inches of mercury column (2488 Pa). This pressure shall be held without introduction of additional air for a period of 15 minutes.

P2503.4.2 Finished plumbing. After the plumbing fixtures have been set and their traps filled with water, their connections shall be tested and proved gas tight and/or water tight as follows:

1. Water tightness. Each fixture shall be filled and then drained. Traps and fixture connections shall be proven water tight by visual inspection.

2. Gas tightness. When required by the local administrative authority, a final test for gas tightness of the DWV system shall be made by the smoke or peppermint test as follows:

2.1. Smoke test. Introduce a pungent, thick smoke into the system. When the smoke appears at vent terminals, such terminals shall be sealed and a pressure equivalent to a 1-inch water column (249 Pa) shall be applied and maintained for a test period of not less than 15 minutes.

2.2. Peppermint test. Introduce 2 ounces (59 mL) of oil of peppermint into the system. Add 10 quarts (9464 mL) of hot water and seal all vent terminals. The odor of peppermint shall not be detected at any trap or other point in the system.

I guess we didn't get the memo about the 'explosive' possibilities of plastic pipe under a whopping 5 psi... :shock: Seriously, if the stuff can't handle 5 psi, what happens when you use a plunger? That's got to generate more than 5 psi.

I know this isn't much help outside of NYS, but every now and then it's nice to see what other places are doing.
 
Re: Pressure testing plastic pipe

A code change has been turned down in the past to NOT allow air testing of plastic for the reasons mentioned above. The proponent has never produced any numbers on accidents. It is on the agenda next week again.

Having been to a pipe manufacture and watched the processing and testing the amount of pressure it takes to blow a pipe is very high. You would have to fall asleep filling it. Now I have seen many Fernco caps pop off which could cause a headache.
 
Re: Pressure testing plastic pipe

On't have my code books in front of me, but I do believe the 03 IPC allowed a 5 psi, 15 minute air test on plastic DWV. The water distribution system can be tested with 50 psi on anything other than plastic. I could be wrong.
 
Re: Pressure testing plastic pipe

Some pex manufactures allow air testing. I had the same documentation from Zurn but can't lay my hands on it right now

From the AQUAPEX Installation Handbook, p56, Testing:

The system must be pressure tested to at least working pressure.

From the Installation Handbook, 6th Edition

SECTION 9: SYSTEM START-UP

Pressure Testing the System

Before the tubing is covered, the system must be pressure tested. Air or water may be used as a test medium. Each manifold may be tested separately or, depending upon the construction schedule, the entire system may be tested at one time. The following is a recommended procedure for pressure testing.

1. Be sure all connections are properly sealed using the supplied gaskets.

2. On end cap with vent, remove air vent and drain cock and replace with proper sized plugs.

3. Install the Wirsbo Pressure Test Kit (E6122000) or suitable pressure test kit onto the system.

4. Pressurize the system with water or air to 60 psi. The system should maintain the 60 psi for a minimum of 24 hours.

5. Depending on the circumstances of the installation, the PEX tubing may expand under pressure and require a one time addition of water or air to offset the tubing expansion.

Maintain pressure on the system during the slab pour or when finished flooring is being installed. This simplifies leak detection if the tubing is damaged during the pour or installation.

If you have any questions, please contact Wirsbo Technical Service at (800) 321-4739.

Elaine E. Hoffman

Technical Services

Uponor Wirsbo
 
Re: Pressure testing plastic pipe

Not for nothing, but doesn't it make sense that you should be able to use at LEAST working system pressure to test anything? Plastic or metal, it needs to withstand working pressure. I realize that water and air exert pressure differently and all that, but 5# on waste lines and 60-100# on supply are well within reason.

cboboggs - For what it's worth, our current NYS Codes are based on the 03 I-Codes. The ICC codes-on-line link still works also.
 
Re: Pressure testing plastic pipe

we'll test with air if the temperature doesn't allow for water testing... but they need to still test with water after freezing is over.

The real secret is to have it holding for at least 1 hour before you try to witness it.. if it's going to fail, it'll be when they put the air pressure on...

but.. they still need to test with water..

having said that, the drywallers will probably hit whatever lines you checked at rough in, anyway.

think of it as job security! ;)
 
Re: Pressure testing plastic pipe

got to go with jar on this one. several years ago i watched a plumber trying to tighten a cap on a four inch line for the under floor air test. i turned away and heard a loud explosion and turned back around to see a huge cloud of dust and the plumber on his keyster.he looked like he had stepped on an ied. i have not allowed an air test on the dwv system since. he was lucky not to have suffered any hearing loss or physical damage.
 
Re: Pressure testing plastic pipe

jd,

5-7 pounds is what these guys would test it at. it really surprised me that that little pressure could make that much noise and dust!
 
Re: Pressure testing plastic pipe

If the plastics industry says not to air test their pipe, like Jar has posted, why do you guys still want to air test it?

I recall remodeling the building department in the basement of the old San Leandro City Hall in the late 60s. The CBO came to me to introduce me to his subordinate who would be handling the rest of the job, telling me he was going to Hawaii, I asked about his "vacation" and he told me that it was all expenses paid by the plastic pipe industry, he would gladly take their "vacation" but it would be a cold day in Hell before plastic pipe was ever used in "his town". A few years later he retired and ABS was approved in San Leandro, where are the good old inspectors like that?
 
Re: Pressure testing plastic pipe

JD,

I agree with you in principle but not in practice. Many times I have witnessed an air test on gas pipe with a 30 psi test gauge that is maxed out. Since their compressor will reach 120 psi there is no way of knowing how much pressure has been applied but it is somewhere between 30 and 120 psi. I encountered a test with the furnace hooked up and the shut-off valve open. The gauge was pegged so I checked it with a tire pressure gauge and it was at 60psi. They will make the same mistake with ABS. I don't want to be in a building with ABS pressurized at 120 psi.

There was a job where the plumber decided to air test cast iron DWV because it was sleeved and some portions were to be encased in concrete prior to a test. He first asked my supervisor if this was acceptable and got a green light to proceed. Then the job became mine. Cast iron will not pass an air test without a lot of grief. Several sections of pipe failed and a pallet load of elbows failed. On top of that, each time an elbow or pipe section had to be replaced, the no-hub fitting had to be replaced because the rubber had formed to the imperfections of the surface of the previous pipe or elbow.

I doubt it was a bad batch of cast iron because this has happened twice. The second time, the plumber insisted that my first encounter with air testing cast iron was a fluke. Now if a plumber proposes an air test with cast iron, I ask if they have ever done that before. So far none have tried it.
 
Re: Pressure testing plastic pipe

We do come here to learn. I'll consider this my lesson for the week. :) Personally haven't experienced it, but I've also never experienced being shot in head and have no desire to do so. :roll:

Now if I can only remember to bring this up at our next Chapter meeting, I'll poll the locals and see what they have experienced. Maybe someone around here has some first hand experience with this type of failure... :?
 
Re: Pressure testing plastic pipe

It takes a LARGE volume of air to test a piping systems so when a failure occurs it will not be a quick relief of the pressure. Ever chop a hose on an air compressor same principal.
 
Re: Pressure testing plastic pipe

5 to 7psi makes the rubber cap expand on the pvc stack with air gauge set at one end, no issues. It's when the plumber's got it pumped up too high and he releases the rubber cap instead of releasing the air at the air inlet, that's when a DANGEROUS situation can occur. I think I'll still test with air, I always check the gauge first and hang around for 15min. then release a little air myself to make sure their not pulling a fast one over me. I don't trust my grandmother either! :D
 
Re: Pressure testing plastic pipe

I just listened to all kinds of testimony on this at the Res P/M hearings. After all the talk air testing is allowed, which I am fine with. Here are the points as I saw them.

1) No information was provided about deaths or injury but hearsay.

2) There are many areas where water is not availible at rough testing time.

3) Many areas water would freeze within a short period of time

4) Manufactures' "recommend" water testing, not "require" it when testing

5) There are many dangers on a jobsite

My feeling is:

1) Hire plumbers that won't fall asleep during the air test

2) I have been to a pipe manufacturer and watched a pipe section test and it took many more PSI then is required for a test.

I invite personal pictures, not internet pictures if anyone has them.
 
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