Swimming Pool Pressure Testing
Pressure testing of swimming pool plumbing lines is one of the worst offenders when it comes to congruency of technical process within the pool industry. There is a
huge difference from one company to the next when it comes to standard practices. Actually, to this day, I still encounter pool companies who still don't pressure
test their lines before doing things like pouring concrete.
These companies usually say things like "I did them myself" or "there are only a few connections and they are good". I am old and tired these days, and I do not do field work anymore, but back in my younger days...them is fightin' words! I have gone to war with countless people over establishing some standards (and integrity) when it comes to pressure testing new pool plumbing installations.
I could genuinely care less if you want to operate a crappy business and likely go out of business one day. What makes me mad is that someone is paying you for this work, and you are representing the industry as a "professional", and at the end of the day your customer is receiving a questionable product. If you are one of those companies that do not pressure test any of your plumbing installations because you are "really careful" then I submit to you the following question:
Did you know that manufactured pipe and fittings can sometimes be defective?
If you are not pressure testing your systems then how can you be sure there is not a hairline fracture in a pipe section, or in a fitting? How can you be sure that you did not forget to glue a fitting, or what if your glued fitting leaks? Don't even try to tell me that you are so good that you never miss a glue joint. I probably killed half of my brain cells due to PVC solvent and cement over the years for all of the thousands of hours I have spent gluing pipes together. I always felt as though my joints were 100% solid, but the reality is that it is easier to mess up a glue joint then you might think.
If you never pressure test your lines, or if you don't pressure test adequately, you will never find the errors in your glue joints. I am an absolute perfectionist in the field, and most likely far more experienced than you when it comes to doing plumbing and mechanical installations, and I still made mistakes...had fittings back off if I was moving quickly, or left a fitting only dry-fit. These things happen. A great plumber is not defined by being perfect. A great plumber is defined by checking, and double checking their work, to ensure a perfect and leak free installation.
Burying a leak in a plumbing system is a worst case scenario for you, your company, and your customer. Avoid this risk completely by thoroughly pressure testing every installation that you do.
Pressure Testing Standards
Throughout my career in the pool industry I have had the opportunity to work with many, many companies. Without a doubt, pressure testing standards, or lack of them,
are one of the most common technical deficiencies that most pool companies share. One of the most common problems relates to a lack of a standardized process for how
to actually conduct a pressure test. It is extremely common for pool companies to pressure test by charging the pipes with 5 or 10 pounds of pressure, look at the
pressure gauge, maybe tap it once or twice, and then release the pressure in the line. This is absolutely not sufficient if you want to actually pressure test the
lines - the only thing a test like this would find would be a completely severed line...which is probably not what you are looking for. Doing a pressure test like
this is just as good as not doing a pressure test at all.
So what constitutes a "good" pressure test? Fortunately we do not need to redesign the wheel. Proper pressure testing for plumbing systems is a technical subject that is already covered in the plumbing industry...we just need to adopt these principals into the pool and spa industry. If you were installing a plumbing system in a high rise construction building then all plumbing lines would be subject to a pressure test that includes the following steps:
1) The entire plumbing system for an installation should be ganged together into a single line for testing purposes
2) The system is charged to between 150% to 300% the value of the maximum designed operational pressure
3) The system is charged incrementally (usually in increments of 10 or 25 PSI) with a wait time for each pressure stage
4) Once the system is charged to the maximum test value it is monitored for leaks for 10 minutes
5) If no leaks are detected the pressure is reduced to 150% of maximum system operating pressure and left for 24 hours
6) Any drop in pressure, even 1/4 lb over 24 hours, would result in a failure of the pressure test
When you take these principals and apply them to the swimming pool industry we need to know a few values. The first is what the maximum operating pressure for a pool system is. 30 PSI is the standard maximum operating pressure that pool equipment is made to handle. 50 PSI represents the hard maximum beyond which failure is imminent. You will also need to know the maximum pressure rating for the plumbing materials that you are using.
1.5" schedule 40 PVC = 198 PSI maximum operating pressure
1.5" schedule 80 PVC = 282 PSI maximum operating pressure
2" schedule 40 PVC = 166 PSI maximum operating pressure
2" schedule 80 PVC = 243 PSI maximum operating pressure
3" schedule 40 PVC = 158 PSI maximum operating pressure
3" schedule 80 PVC = 225 PSI maximum operating pressure
4" schedule 40 PVC = 133 PSI maximum operating pressure
4" schedule 80 PVC = 194 PSI maximum operating pressure
6" schedule 40 PVC = 106 PSI maximum operating pressure
6" schedule 80 PVC = 167 PSI maximum operating pressure
These values represent the maximum operating pressure and not the burst pressure. In most cases the burst pressure of PVC pipe is five times what the maximum operating pressure value is. Many pool technicians do not realize just how high of pressure PVC is designed for. After looking at these values you can begin to see how 5 PSI for a pressure test is simply not going to tell you anything. While PVC is the accepted industry standard there are other common plumbing materials that might be used in pool installations:
1.5" schedule 40 CPVC = 330 PSI maximum operating pressure
1.5" schedule 80 CPVC = 470 PSI maximum operating pressure
2" schedule 40 CPVC = 275 PSI maximum operating pressure
2" schedule 80 CPVC = 400 PSI maximum operating pressure
3" schedule 40 CPVC = 260 PSI maximum operating pressure
3" schedule 80 CPVC = 370 PSI maximum operating pressure
4" schedule 40 CPVC = 220 PSI maximum operating pressure
4" schedule 80 CPVC = 320 PSI maximum operating pressure
6" schedule 40 CPVC = 180 PSI maximum operating pressure
6" schedule 80 CPVC = 280 PSI maximum operating pressure
1.5" flex PVC = 65 PSI maximum operating pressure
2" flex PVC = 60 PSI maximum operating pressure
2.5" flex PVC = 50 PSI maximum operating pressure
3" flex PVC = 50 PSI maximum operating pressure
4" flex PVC = 45 PSI maximum operating pressure
Some important notes to take away from these numbers is that you never want to test a system at a higher pressure than the pipe is designed to operate at. While the burst value is much higher, you should never attempt to exceed the maximum operating pressure for your pipe material - this is your hard maximum.
Another important takeaway from this information is just how robust plastic plumbing pipes are! There is no reason to be testing your plumbing installations to 5 or 10 PSI when the pipe (and the system itself) is designed to operate at much higher values.
Applying the pressure testing standards from the plumbing industry, and adapting for swimming pool operating pressures and the maximum operating pressure of your materials, a pool plumbing system pressure test should include the following:
1) Gang all suction and return lines into a single manifold to test as a complete unit
2) Charge the system in 10 PSI increments with 10 minutes wait time at each stage before applying more pressure
3) Charge the system to 200% of the pool operating pressure (60 PSI) for flex systems, and 300% (90 PSI) for rigid PVC
4) Monitor for leaks for 10 minutes
5) Reduce pressure to 150% of system operating pressure (45 PSI) and leave for 24 hours
6) If any pressure drop, at all, is observed after 24 hours then further leak detection is required
Pressure testing is a critically important technical process if you want to limit your liability from underground leaks for your company. By using an established pressure testing standard borrowed from the plumbing industry you can be sure that you are doing everything you can to minimize your risk of missing a potential leak. While you might feel that this level of pressure testing may be overkill for your company, consider the following:
anecdotal evidence - Once while helping to install a high end concrete pool with an in-floor cleaning system I was staging pressure as described above. I reached the 30 PSI threshold and no pressure drop was recorded during the ten minute waiting period at this pressure level. When I continued the pressure test and increased the pressure over 30 there was a sudden decompression of the line. The failure was tracked down to a completely dry-fit fitting that was in one of the floor zones, that was completely buried in gravel. This pipe, completely void of any primer or glue whatsoever, had managed to hold 30 PSI for ten minutes without leaking. If you think for a second that establishing proper pressure testing techniques is a waste of time, you are dead wrong. The house ended up going up for sale for over $25,000,000 shortly after we finished the project and I still have nightmares thinking about that dry fit connection getting buried under the pool if I had not been so thorough with how I pressure test systems.
Pressure Testing Safety
When you start talking about pressurized systems at 60 or 90 PSI there needs to be a complete and total rethink when it comes to safety. While I may strongly encourage
pool technicians to improve their pressure testing process, you need to be aware that pressure at these levels is extremely dangerous. Even at 5 or 10 PSI a pool
system can be very dangerous if you are not careful. At 90 PSI, if you are not careful, you might kill someone.
When you are pressure testing the first thing that you need to do is close the jobsite. There should be absolutely no people working on, in or around the pool or the plumbing system for the entire time the lines are under pressure. In addition to this, the site should be closed and flagged off indicating the danger, and if you are in a residential environment then you will need to speak with the property owner and make them aware of the danger. Additionally, every single plug, adapter and pressure tester that you use for testing the system needs to be isolated and tied off (with mechanics wire) to prevent the plug from being able to shoot out like a missile.
In addition to the site being completely closed, and all of your equipment isolated and tied off, you need to be wearing some serious safety gear as well. Safety glasses PLUS a face shield, heavy clothing with long sleeves and pants, steel toed boots and hearing protection are the minimum equipment that I would wear for doing a pressure test.
By now you are probably thinking that this is going to take a lot of time for your company to do...closing the site, buying more safety equipment, all for something that you are "already doing". This is simply the price of doing business as a professional pool company. Instead of just trying to absorb these costs into a slim margin process, instead charge more for your services and consult the customer as to why you are doing something that other contractors are not...something really important. Almost every project that I quoted in my career I was one of, if not the most expensive quote. My job, as an industry expert, was to explain to the customers why my price was more, and exactly what they would NOT be getting by going with someone else. The net result of this is I lost the jobs where price was the only concern for the customer, and I got all of the jobs where the customer saw value in paying to have the job done properly. Pressure testing should not be a footnote on your work day. A pressure test is not something that you crack off five minutes before lunch...adopt the established industry standard and charge for your time. Above all else, do not skip on safety if you are going to test anywhere near to the values discussed here.
Pool Pressure Testing Equipment
If you are going to improve your pressure testing process then you are going to need some professional quality equipment. If all you use for pressure testing is two dollar winterizing plugs, then you are going to need to pick up a new set of high quality pressure testing plugs. Having at least a few of the most common sizes of testing plugs made by Anderson Manufacturing is a great idea, if not a full kit, as these will perform much more reliably at the pressures you will be testing at.
If you have $400 to $600 you can buy a pressure testing kit directly from Anderson. The alternative is to just pick up a few high quality testing plugs, but you still need a way to inundate the system, regulate, and monitor the pressure. There are a few versions of pre-built pressure testers that you can buy online or directly from your pool equipment distributors, however most of them are made from PVC. I ended up just making my own, and I recommend that you do the same if you don't want to spend more than you have to.
If you want to build your own pressure tester all you will need are some basic brass fittings like 1/2" brass nipples, a 1/2" brass tee, a 1/2" x 1/4" reducer bushing for the pressure gauge to thread into, and a 1/2" brass ball valve. All you need to do then is add a compressor quick connect so you have a way to charge the system with pressure.
There are certainly more than a few ways to build a pressure tester. Some people like to use water for testing, some air, and some both depending on whether you are hunting for a leak on an existing installation, or inspecting newly installed lines. The way that I liked to set my systems up was to have a half dozen or more testers so that i could leave the entire pool under test. If I have a very complicated plumbing system I will sometimes gang them into two separate tests - one for the suction lines and another for the return lines.
The way that I connect my tester into the system is by installing a 1/2" female thread reducer bushing into the plumbing system and threaded the tester into this along with a thread sealant such as sealant tape. Since these pressure testers are conspicuously missile shaped, I like to tie them off using rebar tie wire which I double wrap, and tie off twice on each tester. If that pressure tester wants to kill me it's going to have to work pretty hard to get itself free. Tie off everything when pressure testing using this method. If the worst ever happens and you have a blowout, you will be very happy that you took the extra time to secure everything, including redundancy.
When I started in the pool industry there was no internet, no cell phones, no GPS tracking or Google Maps...nothing. I had to learn about pressure testing as most others do, the hard way, and finding accurate information about how to do a better job was not always an option. I learned pressure testing organically by seeing how a dozen different unaffiliated companies performed the same job. You only need to work with one company who has developed a better technical process to see the giant flaws in those that have not.
Air Testing VS. Water Testing
Why not both? It depends on what you are pressure testing exactly. For all new pool installations I tend to use only air for the test and no water at all. This is
because the projects that I built were staged and sometimes the pool would sit for extended periods before finishing and start up. If the pipes of the pool are not
blown out completely then the water is obviously disgusting and stagnant in the lines by the time the pool is ready to fill.
Air or water testing are both going to get you the same result, which is to tell you whether the system is 100% good, or not. Some might argue that air compresses and can be more difficult to get an accurate reading from the gauge. This would be true if you only charge the system for a few minutes. If you incrementally increase the pressure and stop at each stage, and then reduce pressure slightly before letting sit for 24 hours, you should have zero problems getting an accurate read from the gauge. Take a picture of it even. If 24 hours later it looks any different, then you have a problem.
The question of air versus water, or both, for pressure testing is a question that relates more to the leak detection process. When doing leak detection on existing systems there can be specific advantages to which you use depending on the type and size of the leak you are looking for, and where the leak is suspected to be in the system. If you want to learn more about pressure testing as it applies to leak detection then you can read this article on swimming pool leak detection which talks about air versus water testing.
If you want to continue learning about pools and spas from an industry expert follow swimming pool Steve on acebook , twitter and youtube