air tanks and receivers.....BANG !!!!

Discussion in 'Help Wanted' started by pp-admin, Mar 4, 2016.

  1. pp-admin

    pp-admin Member

    well hopefully no bang or explosion-EVER !!!

    (and its to prevent the prospect of such an event that I need some wisdom from you gents please)

    I have just bought a 50 year old air receiver. about 300ltrs or so capacity. vertical tower type tank.

    Its fully plated and very very well made in Britain from very thick steel - 3/8" i think.

    It has no damage and actually, though a bit tatty paint wise, looks in very good condition.

    I intend to tart it up, paint it and replace the taps and valves with new ones as well as safety valve and guage.

    Its plate confirms it is designed for working pressure of 150 psi and was hydraulically tested to 237psi (!!!)

    Now the bad news.....

    This old tank has inspection doors held on the old boiler way with inward fitting and screwed clamps on the outside face.

    I have removed these and poked a torch inside. There is clear evidence of rust but it does not seem very bad and is patchy with quite a lot of original paint or primer of some kind still apparent and intact.

    I know that compressor tanks always collect water from the air and iam always surprised at just how much water i can drain off my modern sealey compressor.

    I did not think the condition of my 50 year old tank was bad but I have seen lots of videos and comments about the dangers of exploding air receivers and its worrying as you can imagine. Apparently, commercial premises insurers insist on giving site compressed air receivers a fixed life and mandatory inspections pretty much like steam boilers have to be inspected and tested.

    None of this RISK is something that I have bargained for but it does make sense and is quite worrying.

    A lot of you chaps have old air tanks etc etc and paul evans probably has many ancient tanks on site at IF including the old riveted type (mine is fully welded-no rivets).

    Some rust inside an old tank is unavoidable but there is no way for me to tell if one rust pit inside is deep and could cause an explosion.

    Am i worrying about nothing and being over cautious. Can any of you add some qualified wisdom ??? I really dont want to have to buy a new tank as i like the look of my old british one. Also, any suggestions as to internal rust removal and then an internal anti rust prep or paint of some kind ????

    HELP. !!

  2. petternut

    petternut Administrator

    I can only say that you should get it properly and professionally tested and ultrasound checked.

  3. campingstoveman

    campingstoveman Active Member


    I can only agree with Roland, if through the inspection door you can see rust the Ultrasonic test will tell you the thickness of the metal of the tank and if its to thin you cant use it.

    Martin P
  4. lambe

    lambe Member

    As above. All pressure vessels come under a host of safety regulations, HSAW, PSSR, PSR, PUWER ETC there isn't a fixed life rule, I am aware of some huge ones over 100yrs old in daily use, except for things like fire extinguishers where testing and inspecting exceeds value, or of questionable quality :shock: . The test pressure is normal at one and a half times working max there should be date of manufacture, maker, working and test pressures and testing authourity. I work with steam boilers, the rule is always work safe, have it professionaly NDT checked it isn't expensive.
  5. grendel

    grendel Member

    Fill the tank with 98% water.
    Put 1,5 times working pressure on the tank and if nothing happens, you'll be ok.
    That is how they are normally tested.

    Be careful with changing valves. Not all are up to full pressure.

  6. petternut

    petternut Administrator

    That is out of date in the UK.

  7. JohnM

    JohnM Member

    +1 for a hydraulic test. I have an air receiver that's c40 years old but has done little work. I too was getting worried about it so decided to strip everything and get it professionally tested. Unfortunately, the threaded inspection plugs refused to move. It's plated for 150psi working and had an original proof test of 300psi. I bought a hand pump from screwfix, filled the receiver with water and presurised it to 300. It creaked a bit but no leaks or bangs. If it will take 300psi, 150psi should be well in hand.

    The professional boiler testers I used in industry always insisted on a full hydraulic test every so many (5 I think) years.

    A hydraulic test will certainly give you peace of mind about your old receiver.

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