HYDROTEST PROCEDURE OF HEAT EXCHANGER AT SITE. Can anyone please point me to a source for determining the correct procedure for hydrotesting the various types of heat exchangers? Thanks. ASME Pressure vessel/ Heat Exchanger Hydrostatic test (for Internal Another method to find out the minimum test pressure is using the MAP.
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It is easier to test then pressure testing in the shell with water to find leaking tubes. For such equipment small leaks of high-pressure feedwater through the tube-to-tubesheet joints leads to wire drawing wormholingwhich when severe can be extremely expensive to repair, especially when considering the loss of cycle efficiency when the heater is bypassed to allow access for repairs. As far as I know that the hydrotest by air is safety concern exchnger water is usually used.
HYDROTEST PROCEDURE – PDF Free Download
The minimum hydrostatic test pressure at room temperature shall be 1. Leak rates vary inversely with fluid viscosity. Basically one man at hrat head side with an airgun and another at floating head side to plug the other end with a pressure gauge. An analysis of the pressure testing process which hydrostatic test water is applied in the tubeside of an exchanger where the backside of the tubesheet is not visible was adapted from material previously published on the MGT Inc.
I do not need to research the test pressures, just the methodology. We do air tests on the individual tubes to identify leaking tubes. Designers, Users, and Manufacturers should agree on the definition of joint prcedure and to the nondestructive Tests NDT for all welded joints. Pressurize tube side to the corresponding design pressure.
Figure 1 Such testing has beneficial effects on the structure in addition to possibly cracking subsurface porosity bubbles and disclosing cracks in the welds. The range of the pressure gauge should be as per applicable code. Loss of test gage pressure during ASME Code required hydrostatic testing does not disclose very small leakage weeping from the channel side to the shell side because of the insensitivity of the test gages used industry wide for hydrostatic testing.
ON HYDROSTATIC TESTING HEAT – Free Download PDF
I hope this helps you out. The gages in widespread use in the heat exchanger and pressure vessel industries for hydrostatic testing to meet the Code requirements are dial type Bourdon tube gages. The air test is ezchanger a hydrotest, with the hydrotest you evaluate the structural integrity, with the air test you localize problems. The test pressure shall be held for at least 30 minutes.
Can anyone please point me to a source for determining the correct procedure for hydrotesting the various types of heat exchangers? This is especially so when the tube side hydrostatic test pressure is substantially higher than that of the shell side. I have seen incidents with air hydrotesting that caused procecure of some vessels.
ON HYDROSTATIC TESTING HEAT EXCHANGERS.pdf
The simplest and least costly yeat test is gas-bubble testing often erroneously described as soap bubble testing. If the exchanger service is for a fluid less viscous than water the likelihood of leakage in services may be very high if the Manufacturer relies on changes in the pressure gage reading to assess whether there is leakage from the channel side into the shell during hydrostatic testing.
This is a very effective way to disclose leaking tube-to-tubesheet joints. Are you an Engineering professional? Repeat operations as stated for Tube side and Shell Side above.
The Code is a pressure containment safety code and the hydrostatic test represents only a test adequate for the typical heat exchanger not in a specific service where leakage is an issue.
I remember air tests excyanger conducted for some vessels exchannger taped all flanges to detect leaksbut rather as an exception to the rule. Typically, the Manufacturer pressurizes the shell with air or nitrogen at 30 to 50 psi and applies a commercial bubble former to the tube-to-tubesheet joints.
hyrotest It is necessary to understand the service of the exchanger and the degree of hazard such leakage presents. Therefore, typical feedwater heater procurement specifications require helium leak sniffer testing mass spectrometer testing the tube-to-tubesheet joints during manufacture. Close this window and log in. For tubes welded to the tubesheet and subsequently expanded, the prudence suggests that in addition to such leak testing the welds should be fluid profedure examined.
This practice satisfies the TEMA requirement that leaks at the tube joints can be detected at least from one side.
This includes the possibility of wiredrawing wormholing in high pressure closed feedwater heaters in which a leak of high pressure feedwater through the tube-to-tubesheet welds can erode the steel under the weld overlay to which the tubes are welded.