Reply To: Pressure integrity

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Avatar photoSylvanLMP

    Hi Kathy, If your inquiring about a pressure vessel then the ASME section IV is the actual place to look for this aspect of the system.

    As a Master Plumber and unfired pressure vessel and low pressure boiler inspector I did many hydrostatic tests of pressure tanks relating to either hot water storage tanks or air tanks used for Johnson pneumatic controllers (great system by the way)

    The actual designed working pressure of the majority of fittings used in the plumbing trade has a rating of 125 PSI But as the temperature goes up the pressure rating drops.

    When testing any vessel it is common practice to only use water and NEVER air pressure as water for all intensive purposes water cant be compressed and air can cause a very violent reaction.

    Here is a little article I work about a year ago concerning storage tanks and pressure testing.

    Now for filter filtration systems they create their own problems with some having back flow preventers installed on process hot water applications and even the ASME states that a low pressure boiler is up to 160 psi and or 260 degrees BUT what happens when a pipe ruptures allowing this scalding water to flash into steam.

    Another type of testing popular with toxic “Filtration systems” is Negative pressure testing where you want the vacuum breakers to not allow any back syphonage like we used do on embalming tables.

    We didn’t always have either an air gap or an air break in certain countries (5th world)

    For example pressure integrity in the filtration systems I do inspect is to guarantee a positive pressure for example.

    I have installed a hot water boiler on the upper floor of a 7 story building BUT the problem is what happens if for some reason a pipe on the lower floor springs a leak?

    We cant always rely on a low water cutoff to not fail, we also have to make sure the leak will not drain the boiler and let it possibly dry fire (melt down).

    Another problem with this kind of equipment is suppose there is a shut down in the basement and someone opens a drain valve? Depending on the height of the building would account for the severity of the implosion of the vessel ( ever see a steel tank crush in LOL)

    So we try to compensate with the means of a positive displacement pumping station, so if the pressure drops the Federal pumps to B&G kick in. to maintain a possitive pressure .

    Please feel free to E mail me privately as I can give you a more detailed explanation if I knew the exact application your looking for.

    Most license plumbers are well aware of testing most fluid handling applications as we follow lots of codes.

    [Edited by SylvanLMP on 18 October 2000]

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