Hydro-test for Re-certification

[Kannan492]

The Hydro-test was for the Re-certification of the Fire tube Boiler. The previous pressure test was done at 13 Bar one year before. Now again for the re-certification, the pressure test was done at 11 Bar. Is there any reasons for the same. Again the TPI will come to verify the working pressure. Will that also be brought down and checked at a lower compared to the previous years readings.

 

[GenB]

Oh. Under what Code this will be done and what Jurisdiction? Under the NBIC If an annual inspection and the boiler is in sound conditions there are no grounds for alteration,creating the op pressure should be the same.

 

[sharmass]

You can't rectify a boiler just by hydro test unless your local jurisdiction allows.

 

[metengr]

Are you talking re-certification or obtaining an Operating certificate from the local Jurisdiction for an aged boiler?

 

[Duwe6]

"When is a hydro test not a hydro test?"

On almost all boilers and unfired pressure vessels, there is only one Code Hydrostatic Test, where the pressure is 1.3 or 1.5 x MAWP [Design Pressure]. This is the final step required before being allowed to apply the ASME Code Stamp. Unless that boiler/vessel is Altered in a major manner, it will never require the Code hydro to be reperformed. And for a plethora of good reasons, you DO NOT want to repeat the Code hydro on a used and/or in-service vessel. Think of it as a proof-test applied ONCE to a brand new item.

For boilers, one of the items that a good inspector looks for is a Leak Test of the tubes [and the remainder of the boiler] as it is being readied for return to service. The feedwater pump(s) fill the boiler and pressure it up to, but not exceeding, the MAWP. This pressure is applied to check the integrity of the system, but it never exceeds the MAWP. It is very poor practice to refer to this Tightness Test / Leak Test as a 'hydro', because it leads folks to think that the boiler is being given another Code Hydro Test.

 

[metengr]

Unless that boiler/vessel is Altered in a major manner, it will never require the Code hydro to be reperformed.

I wish it were true because I don't agree that an in-service boiler should be subjected to a code hydrotest. However, there are Jurisdictions in the US that mandate a "code" hydrotest after a certain age to provide suitability for service and to obtain an operating certificate. Again, I do not agree with this approach.

 

[Duwe6]

"Again, I do not agree with this approach." Exactly; that is why neither ASME nor National Board require this. I had forgotten/never heard of a Jurisdiction Inspector doing this. And since he/she is the Inspector, it is impossible to argue with them. [especially when they are wrong ]