Quality and Service Since 1936

How NOT to install a compressor for a dry pipe sprinkler system


After reading our post "DO NOT USE A RETAIL AIR COMPRESSOR FOR A FIRE PROTECTION APPLICATION" David Walencewicz of P&J Sprinkler Company in Connecticut felt the need to share some pictures of a horrifying air compressor installation that he recently came across. We at General Air Products all died a little inside having looked at these.

Also let me state clearly that this installation was NOT done by P&J Sprinkler Company. They were called in by the State, years after the install, to prepare the building for winter by removing water trapped in the low point drops. David did bring this situation to the attention of the new building owners but the building is now vacant and they plan to demolish the entire structure in the near future.

Bad Air Compressor Installation on Dry Pipe Sprinkler SystemWhen I look at these pictures the first thing I think is - what is the point? If this is the state of the air compressor installation, the heart of the entire dry pipe system, then what is the point of the fire sprinkler system in this building?

The first thing I want to call out here is that this is obviously an "off-the-shelf" tank mounted, lubricated, portable air compressor. The huge wheels are a giveaway that this product was not designed to be used in a fire safety application - but hey, they probably saved a few bucks, right?

If you look closely you can even see that there are straps running around the motor and the tank to reduce the vibration and stabilize the unit. As this is a portable air compressor, not meant for a permanent install, the vibration was most likely causing the air compressor to dance across the floor to the point where it either pulls out the rubber hose that connects it to the system or the plug in the wall that powers the unit (more on that further down).

The next thing that is apparent is that the unit is too close to the wall. There is not enough room allowed for the heat generated by the motor to cool. Even if this were the right air compressor for the job it would still overheat quickly due to lack of ventilation.

Another big problem that is visible in this picture is the extremely dirty environment. Obviously the compressor or valve rooms are not always going to get the white glove treatment but this is well past acceptable. The amount of dirt in this room is going to cause blockages in the intake filter which will then cause the compressor to run more and work harder to meet system demand which will in turn dramatically shorten the life of the air compressor. (Tip: When you go on a service call, take a minute to clean out the area around the compressor and to visually inspect the intake filter to ensure that it is reasonably clean. Then talk to your customers about properly maintaining this area.)

Mystery Solenoid Valve Installation Here is a close up showing the outlet of the air compressor to the inlet of the dry pipe system. First, a rubber hose is used and that is against code. While it is a good idea to use a stainless steel flex hose between the compressor and the system inlet to reduce vibration and noise, a rubber hose is not acceptable.

The next thing that jumped out at us is this mystery object between the rubber hose and the hard pipe to the system. David W. says that it is a solenoid valve, we can also see that it is wired to something.

This picture has been reviewed by several of our seasoned customer service representatives and it's purpose remains a mystery. It might be intended as some type of regulation control similar to an air maintenance device but that doesn't add up to what is required by code. We have never seen anything like it and hope to never see it again.

Bad Air Compressor Installation - Compressor Room In this picture you can see the overall compressor room with the dry pipe valve in the background.  What we also noticed is that this air compressor is plugged into a wall outlet.  As we are sure you know an air compressor must be hard wired to the main power source and on a dedicated circuit.  Then again when you buy an off-the-shelf air compressor, designed for home use, it has a plug at-the-ready. The temptation of convenience must be overwhelming.

I'm sure if we put a microscope to these images we could write a book on all the problems depicted. However, there is one major issue to focus on though, when you are looking to save a few dollars is the air compressor, the heart of the sprinkler system,  really the best place to do it?

If you have pictures like this that you would like to share with us, please email them to me by clicking here. Also, please take a look at this call for pictures from a previous blog post. Finally, a big thank you to David Walencewicz at P&J Sprinkler Company for sharing these with us!

5 comment on “How NOT to install a compressor for a dry pipe sprinkler system”

  • [...] But why is it so common to see retail air compressors in the field? (For a terrifying example of an off-the-shelf air compressor installed in a dry pipe sprinkler application click here.) [...]

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  • Paul W

    Most importantly, is it an NFPA requirement to have a UL listed or approved air compressor installed for a dry-pipe system? I cannot find the requirement in NFPA 13. Provided there is no requirement, I submit that in 38 years in the fire sprinkler industry I have worked on installations with at least 10 different brands of air compressors. I have found that off the shelf units have lasted nearly as long as the most expensive brand, so the Owner gets 3 years at $300 vs. 4 years at $800. Which item is the Owner going to choose? Did you buy your same make lower model car for the least or pay more for the highest model? To me that is a much more relatable example than different types of light bulbs. Tools and fire pumps and fittings are similar purchases in the fire sprinkler industry.

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    • ray

      You are correct about the listing requirement though, with all respect, I disagree that the requirement is the most important aspect - quality is the most important aspect as far as we are concerned. As for your experience with retail compressors used in fire protection applications, what you describe differs from all that we see on a day to day basis. You have defied the odds. Our testing shows definitively that comparable style retail air compressors are designed to operate far below 1000 hours while ours are expected to run far more than 5000 hours. When you factor in the wear and tear of short runs, and constant on and off at low pressures the air compressors found at retail locations just don't match up in performance or longevity to our fire protection air compressors in this application. We say this with confidence based on our 50 + years of experience building, troubleshooting and testing air compressors for fire sprinkler systems. Finally, almost all retail compressors have their warranty voided when they are put to use in any commercial or industrial applications - NFPA requirement or not, even the manufacturers of the type of air compressors you reference do not want to see their compressors permanently installed in a sprinkler system.

      Reply
  • […] But why is it so common to see retail air compressors in the field? (For a terrifying example of an off-the-shelf air compressor installed in a dry pipe sprinkler application click here.) […]

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  • Tarun

    Excellent topic and really helpful

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