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ASME requirements for expansion tank

Rocky_2
Rocky_2 Member Posts: 89
in THE MAIN WALL
Under what conditions do I need to use an ASME rated expansion tank on a boiler system?

Comments

  • marc
    marc Member Posts: 203
    ASME

    I believe it is required in systems where the pressure relief is above 30 #, but the local jurisdiction may have more in mind. Also, when installing an ASME expansion tank and you isolate the tank from the boiler relief (ball valve,ect) you are required to install a relief on the ex. tank. Marc
  • Unknown
    Unknown
    what do

    What do or how reilef valve will work on ex tank if the ball valve is closed, there no pressure change unless the fill valve is on the tank side of valve and opened...
  • Perry_2
    Perry_2 Member Posts: 381
    The General Rule is

    any tanks rated over 15 PSI would need to be ASME stamped; however, there may be exceptions for small volumn tanks such as those used for home boiler systems.

    I'll send an email to myself at work and if I get time - or the right person is in today - I'll either look it up or ask. The ASME code books are no less than 20 ft from me (and we probably have over 1/2 of the code books in the ASME series at work; even multiple copies of some of the sections).

    If there is a small volume exemption - I'll let you know the cut off size.

    Perry
  • Brad White_9
    Brad White_9 Member Posts: 2,440
    Temperature

    If I gather the situation you are describing, that the ball valve is the fill source which is closed. Any captive volume of water requires a relief valve and expansion tank, the pressure increase (or decrease but who cares?) is due to thermal expansion. Boyle's Law.
  • Brad White_9
    Brad White_9 Member Posts: 2,440
    Public or Commercial Work

    Any public facility or commercial work gets an ASME H-stamped tank (all unfired pressure vessels for that matter) in our office. Given that is practically all of our projects, they naturally all get them.
  • Greg Gibbs
    Greg Gibbs Member Posts: 75
    Two and a half times the...

    working pressure of the boiler.
    That is the req. in the great state of Colorado. If the boiler has a 30psi relief valve (AND THE RATINGS PLATE SAY’S 30PSI):
    30 times 2.5 = 75 ……you can use a non-ASME tank.
    If the boiler has a 50 psi relief valve (AND THE RATINGS PLATE SAY’S 50PSI)
    50 times 2.5 = 150……..you must use an ASME tank.

    This came straight from the State Boiler Inspector Randy Austin (This was about a year ago when I spoke to him)

    A.S.M.E = ALMOST, SOMETIMES, MAYBE, EXCEPT



  • marc
    marc Member Posts: 203


    the relief is for excessive pressure during a fire. (inspector explained this) since you have a normal tank inside of a armour plated tank. the theory as i was told is during a fire the ASME tank could reach explosive temperatures, then the fireman sprays water on the tank and boom!!! during the fire someone must also turn off the service valve on the ASME tank. Very unlikely, but still required in at least one area we work in. this inspector is mostly commercial and stays ontop of the codes, unlike most of the others who allow just about anything. marc
  • Unknown
    Unknown
    A.S.M.E.

    Almost. Sometimes. Maybe. Extortion fees.
  • Perry_2
    Perry_2 Member Posts: 381
    What the Authorized Inspector said:

    For home heating applications state and local exemptions dominate in the US, regardless of the ASME code. Not all states have adopted the code either (even for huge pressure vessels or for Section III and Section XI which is nuclear vessels and nuclear inspection programs).

    If the state has adopted ASME code, or at least Section VIII in its entirety, there are exemptions for vessels under 6", exemptions for small volume (several cubic feet) under a modest pressure (but the AI did not know the pressure off the top of his head), and other exemptions that may apply to air bladder over water (well water and home heating systems).

    I could not locate a current code year Section VIII in the few minutes I had to look at the exact exemptions in Section VIII today (otherwise, it was a 12.75 hour day with lots left todo over my "free" weekend).

    Key here is to check the local regulations.

    Commerical work and apartment buildings almost always need code stamped vessels.

    Perry
  • wog
    wog Member Posts: 1
    service supervisor

    need to know what the requirements are for asme expansion tanks in college buildings in Burlington Vermont
  • jumper
    jumper Member Posts: 2,403
    what Perry says but....

    Whatever the guy in charge says. What about a repurposed boiler, for example. Originally used for process work it has an ASME 50 psi plate on it. Now used only for heating and has 5 psi pressure relief safety. Insurance inspector points to ASME stamp and demands 75 psi static test. What to do ?
  • tim smith
    tim smith Member Posts: 2,835
    Re: asme req on expansion tanks

    City of Seattle adopted the asme code. This is how they read it. if a boiler is limited rated at 200,000 btu input or under and is limited to 210 degrees or under a non asme expansion tank may be used unless in a place of public assembly or place of worship???? don't know why. Then only if it is under 2.5 or 3 ?? (can't remember) cft of volume on tank can it be non code tank.  In all other occupancies the above input and temps govern it "except" if tank is under 5 cubic feet or appx 33 galons a non code tank can be used. That is how our jurisdiction reads the asme code. side note: tank must be rated for boiler max wp also.  Good luck, Tim 
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