LEAK TEST OR BUBBLE TEST

 LEAK TEST OR BUBBLE TEST

Leak test merupakan test untuk mengecek ada atau tidaknya kebocoroan. Untuk heat exchanger biasanya dilakukan pada joiny nozzle pad to shell. Leak test dilakukan dengan udara bertekanan pada pressure yang tidak lebih dari 25% dari design pressure (as per ASME V, 2010) dan cairan sabun. Leak test ini juga sering  disebut bubble test.

Untuk holding time leak test, bersadasrka ASME V dilakukan minimum 15 menit. 

Istilah-istilah dalam Leak Test or Bubble Test:

·      dew point temperature: that temperature at which the gas in a system would be capable of holding no more water vapor and condensation in the form of dew would occur.

·        dry bulb temperature: the ambient temperature of the gas in a system.

·   immersion bath: a low surface tension liquid into which a gas containing enclosure is submerged to detect leakage which forms at the site or sites of a leak or leaks.

·        inert gas:  a gas that resists combining with other substances. Examples are helium, neon, and argon.

·    instrument calibration: introduction of a known size standard leak into an isolated leak detector for the purpose of determining the smallest size leakage rate of a particular gas at a specific pressure and temperature that the leak detector is capable of indicating for a particular division on the leak indicator scale.

·       leakage:  the fluid, either liquid or gas, flowing through a leak and expressed in units of mass flow; i.e., pressure and volume per time.

·     quartz Bourdon tube gage: this high accuracy gage is a servonulling differential pressure measuring electronic instrument. The pressure transducing element is a one piece fused quartz Bourdon element.

·      sensitivity: the size of the smallest leakage rate that can be unambiguously detected by the leak testing instrument, method, or technique being used.

·     soak time: the elapsed time between when the desired differential pressure is attained on a system and the timewhen the test technique is performed to detect leakage or measure leakage rate.

·    standard dead weight tester: a device for hydraulically balancing the pressure on a known high accuracy weight against the reading on a pressure gage for the purpose of calibrating the gage.

·    thermal conductivity detector:  a leak detector that responds to differences in the thermal conductivity of a sampled gas and the gas used to zero it (i.e., background atmosphere).

·    vacuum box: a device used to obtain a pressure differential across a weld that cannot be directly pressurized. It contains a large viewing window, special easy seating and sealing gasket, gage, and a valved connection for an air ejector, vacuum pump, or intake manifold.

·         water vapor: gaseous form of water in a system.