Is PVC Pipe Alright to Use with Compressed Air?

A question arises every now and then on whether or not PVC pipe, yes the stuff from your local hardware store that says it is rated for 200 psi, is safe to use as compressed air supply line.   The answer is always the same,  NO! OSHA agrees – see their statement here.

Schedule 40 PVC pipe is not designed nor rated for use with compressed air or other gases.  PVC pipe will explode under pressure, it is impacted significantly by temperature and can be difficult to get airtight.

PVC pipe was originally designed and tested for conveyance of liquids or products that cannot be compressed, rather they can be pressurized.   The largest concern is the failure method of the piping itself.   When being used with a liquid that cannot be compressed, if there is a failure (crack or hole) then the piping will spring a leak and not shatter.   When introducing a compressed gas, such as compressed air, if there is a failure the method ends up being shrapnel.  This YouTube video does a good job of illustrating how the pipe shatters.

While it may seem that it takes a good amount of pressure to cause a failure in the pipe, that is often not the case.  I have chatted with some local shop owners who decided to run PVC as a quick and cheap alternative to get their machines up and running.

They each experienced the same failures at different points in time as well.  The worst one was a section of PVC pipe installed over a workbench failed where an operator would normally be standing. Luckily the failure happened at night when no one was there.  Even though no one got injured this still caused a considerable expense to the company because the compressor ran overnight trying to pressurize a ruptured line.

Temperature will impact the PVC as well. Schedule 40 PVC is generally rated for use between 70°F and 140°F (21°-60°C). Pipes that are installed outside or in non temperature controlled buildings can freeze the pipes and make them brittle.

If you haven’t worked with PVC before or do not let the sealant set, it can be hard to get a good seal, leading to leaks and a weak spot in the system.

The point of this is the cheapest, quick, and easy solutions are more often , the ones that will cost the most in the long run.

If you would like to discuss proper compressed air piping and how to save compressed air on your systems, please contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

Image courtesy of: Dennis Hill, Creative Commons License

Need More Capacity? Start By Finding it in House or Renting

I field a decent number of calls from companies that are trying to expand to new lines or venture into an area of production that they have not crossed into before.  Maybe it is bringing a process in-house that they traditionally outsourced, or altering a process that now requires a large scale blow off operation. In many cases, as these companies grow and succeed, their compressed air systems grow with them. Some of them need to find out find out how much air they will need if when they make decisions to bring processes in house or expand a current process.

One of the first options when needing more capacity from your current compressed air system is to take a look at the existing demand side and determine if we can free up enough supply to meet the requirements of this new option.   Let’s say for instance a new 60″ Super Air Knife is needed.   To test that unit at 80 psig inlet pressure we would need to free up 174 SCFM of compressed air. In all the years we have been around it is still surprising to consult with customers who are using large numbers of open blow-offs, homemade air knives, coolant hoses and nozzles for compressed air etc. These companies can find that extra capacity in their current systems by retrofitting engineered solutions on to the aforementioned poor solutions for keeping compressed air efficient. IF you are using some of those solutions, call EXAIR today to find out how much air our products may save you.

In the event that is not possible to find the necessary new volume of compressed air by streamlining your current system, it means looking at adding compressor capacity.  Some companies think they have to go out to buy a new compressor immediately, simply to test this new process.   That is more often than not, false.   The best recommendation I have is to look into renting a compressor, much like the one shown below.

A Rental Tow Behind Air Compressor
A Rental Tow Behind Air Compressor
The compressor distribution piping.
The compressor distribution piping.

I saw this unit while I was jogging, well attempting to jog, on my lunch break.  This was outside a local company that apparently, going through a very similar scenario like I mentioned above.  When I looked a little closer, I noticed the unit included around a 75-100′ of hose that did not use the dreaded quick disconnect fittings everyone sees.  Instead it utilized what I know as a Chicago style air fitting which does not restrict the air flow nearly as much as a quick disconnect and permits you to utilize the largest volume of compressed air from the compressor – remember folks: properly sized compressed air lines and fittings are extremely important when needing to keep volume and pressure of compressed air at high levels.

A Chicago Style Air Fitting
A Chicago Style Air Fitting

 

Once I looked up the statistics on the compressor I found that it will generate up to 375 CFM at 150 psig.  This is more than enough to test or run a 60″ Super Air Knife and validate whether additional compressors are needed, as well as if the Super Air Knife will perform to meet your needs.   Then, when you are done with the test, you can simply return the air compressor. Based on the results of this test, this could be another point to decide if you could save the needed air from your current system or if you would require a new compressor.

The EXAIR Guarantee
The EXAIR Guarantee

The moral that I am trying to instill in this blog is simple.  If you have a need for more compressed air to validate a new or improved process, don’t hesitate to think outside of your existing system. Where there is a will and a need, there is a way.  If it doesn’t work, take advantage of our 30 day unconditional trial.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF