Compressor tank explosion

[JohnFreeman]

I installed an elbow and a ball valve at the bottom of my 30 gal vertical. I always crack it open when I'm shutting down and bleed off the air...and water. Given that I live in NC, there's ALWAYS water. So far it's always clear though (no tinge of any rust)

 

[bad_idea]

Hello all. Thought this was a good thread to revive as a sobering thought. Take care.

 

[Givl Reggin]

This is one of the reasons I have my compressor outside in a closet bolted to the concrete pad - it it blows it will likely take the doors off the hinges.

 

[Chris.Santamarina]

This is one of the reasons I have my compressor outside in a closet bolted to the concrete pad - it it blows it will likely take the doors off the hinges.

Back in 2001 I worked on a 125 HP Joy rotary compressor that was owned by a huge manufacturing company that made electrical outlet boxes (Eagle Electric). The unit was a huge leaker that the customer refused to fix it due to its age. I had performed a shaft seal replacement due to it ******* out huge amounts of oil when shut down, but the other leaks were just as large. Its oil capacity was 25 gallons and leaked so much that it needed to be topped off every 2 days. The in-house mechanic that worked for the customer used to do the day to day visual inspection of the plant equipment. He jumped out the high temp switch because he got tired of adding oil and resetting the unit every 2 days.

I responded to an emergency call on a Sunday saying that the compressor had a problem and shut down. When I arrived I went to take the freight elevator down to the mechanical room to see what happened. Both freight elevators had been destroyed, doors sucked in and the shafts collapsed. The staircase down to the lower level was gone and an extension ladder was in its place. As i got down to the mechanical room I found the Joy Compressor, both Quincy 100 HP back up compressors, 2 boilers and a 1000 gallon air receiver in pieces. Upon investigation I found that the Joy compressor had the high temp switch jumped out again and the unit ran until the oil was gone. The remaining oil atomized into a gas and when the boiler ignited it lit the gas in the air. The combustion caused the compressor to explode along with the 1000 gallon tank next to it. The force of the explosion from the compressor and the Air Receiver destroyed the basement and everything in it.

I had pictures back in the day and it went into our company manual of why not to jump out safety devices on compressors. My wife hates what I do for a living because 12 hours a day I am at risk of this happening to me. I love the work but when you work with pressure vessels of any type its scary. A new tank is just as much at risk of explosion then a tank 20 years old. In NY City it is required to hydrostatically test these tanks every 5 years. We charge a premium for that test and its not worth the money spent. That certificate is actually only good for the day it was done. The tank could blow up 10 minutes after passing the test. Scary ****, trust me.

Chris

 

[Bo Beering]

After reading this thread - wow! Even the one just posted above from Chris ^^^.

I've been around all types of compressors from engine driven twin wheel barrel types to 4 cylinder factory industrials. Antiques to new HF cheapo's. Lot's of good pointers of what to look for and why but should include the term condensation. Depending on the climate of where the tank sits, warm and cold cycles, tanks will corrode even without running.

 

[Hoss356]

In NY City it is required to hydrostatically test these tanks every 5 years. We charge a premium for that test and its not worth the money spent. That certificate is actually only good for the day it was done. The tank could blow up 10 minutes after passing the test. Scary ****, trust me.

Chris

That doesn't add up, most high pressure vessels are required by the DOT not the local AHJ, but you are in New York... As far as the tank blowing up 10 minutes after the test, I'm gonna have to say that it won't if you're testing correctly and if one does ever rupture right after you've tested it I hope your insurance in ironclad. If you don't believe me consult the DOT, they wouldn't have put requirements like this together for no good reason.
http://www.c-f-c.com/gaslink/docs/dot_cylinder.htm

 

[chris142]

I wonder is wrapping the tank with say a piece of chain would help contain it? Or would it send chain pieces flying too?

 

[Chris.Santamarina]

That doesn't add up, most high pressure vessels are required by the DOT not the local AHJ, but you are in New York... As far as the tank blowing up 10 minutes after the test, I'm gonna have to say that it won't if you're testing correctly and if one does ever rupture right after you've tested it I hope your insurance in ironclad. If you don't believe me consult the DOT, they wouldn't have put requirements like this together for no good reason.
http://www.c-f-c.com/gaslink/docs/dot_cylinder.htm

You are refering to a Portable Gas cylinder. The DOT has nothing to do with the testing of stationary pressure vessels in NY City. Portable gas cylinders are DOT regulated, not stationary Air Receivers. The FDNY is the organization that requires all businesses and home owners that live within the city limits to have their Receiver tanks tested every 5 years.

As far as a tank blowing up 10 minutes after a test has been conducted, it has nothing to do with the testing method or if it was conducted properly (not saying an improperly done test cannot be a cause). Stationary Air Compressor Receivers are rated for 200 psi max usable pressure unless tagged otherwise (high pressure breathing air would be rated to 5000+ psi (DOT approved cylinders, these cylinders are tested using ultrasound). The tests are performed at a higher pressure, but the contents inside the tank is water with the slight air gap pressurized to 300 psi (low pressure Receiver, Hydrostaic Testing). Any leaks will be that of water. However, once a pressure vessel has been put back into service the Receiver is now the responsibility of the owner. If a safety device fails to shut down the compressor (pressure switch) or the safety valve installed is removed or replaced with a larger one, the tank will blow up. The service company that performed the test is not liable for the damage. All of our tests are documented with: National Board# (no #, test failed), pressure switch manufacturer and set pressures, safety valve manufacture and pressure set point and CFM rate, test pressures, etc. Ultimately the tank is the responsibility of the owner and the fines for a violation are very stiff and rather expensive.

Chris

 

[Chris.Santamarina]

I wonder is wrapping the tank with say a piece of chain would help contain it? Or would it send chain pieces flying too?

Im not sure how to answer this except to say that I hope your not standing in front of it if it blows up. A tank with pressure in it is no different then a grenade. Nothing will contain it if its going to pop.

Chris

 

[littletoes]

Now your making a bit more sense to me.....The National Board (Hartford), NOT New York City itself, sets the standard for Pressure Vessels.

It actually is an "insurance" thing for large pressure vessels, although city inspectors WILL inspect boilers, they don't inspect all pressure vessels like Hartford does.

 

[Chris.Santamarina]

Now your making a bit more sense to me.....The National Board (Hartford), NOT New York City itself, sets the standard for Pressure Vessels.

It actually is an "insurance" thing for large pressure vessels, although city inspectors WILL inspect boilers, they don't inspect all pressure vessels like Hartford does.

I was not referring to who sets the standards but however who hands down the fines for not having a tank inspected. All new Air Receiver tanks come with a National Board #. However one with a missing steel tag fails immediately. I live in NY and am very familiar with the laws as it pertains to Air Receivers as it is what I do to earn a living. NY City requires testing of Air Receivers every 5 years, not the entire state, just the City (Brooklyn, Queens, Manhattan, Yonkers, Bronx). Long Island (Suffolk/Nassau) nor Upstate NY required these tests. In NYC it is the Fire Department (FDNY) that enforces this requirement not Hartford. I cannot speak for what is law in other states, just my own.

Chris

 

[camarotoolman]

Besides the noise, another good reason the put the compressor outside away from the work area.

 

[sberry]

Thousands of people killed and injured on motorcycles every year,,, one picutre of a exploded comp tank makes its way to nearly every internet forum,, hmm.

 

[olytdi]

I, too, think that this is immensely rare.

Wanna go through life frightened and worrying when your jig is up? Get in a car.

 

[littletoes]

I work on hundreds of pressure vessels, with no worries. Some the size of a small house.

Done as many hydro tests too. In Washington, to perform a hydro, there must be minimum of two operators present to perform one. To weld on a pressure vessel, you must have an "R" stamp.

 

[redwrench60]

I, too, think that this is immensely rare.

Wanna go through life frightened and worrying when your jig is up? Get in a car.

Yeah but when you are messin' with a compressor tank and your jig is up I don't want to be standing next to you!

 

[Jack Burton]

I know NYC has all sorts of strange rules about firearms, knives and such.

If I read these posts correctly, NYC requires a water test of low-pressure vessels. If the vessel was sound to begin with, wouldn't these tests actually lower the life expectancy of the vessel by routinely exposing the tank walls to water? In this day and age, it sounds like a redundant and potentially negative way to test a vessel.

 

[DekeT]

I wonder is wrapping the tank with say a piece of chain would help contain it? Or would it send chain pieces flying too?

Did you see the Mythbusther episode where they used a chain in an old cannon? I still get chills recalling the destructive force of that flying metal.