Hydrotest Requirment For atm line

[SmallInfo]

Greetings!

1)Seeking for guidance from experts about hydrotest requirements for atm line.
2)Can we reduce the hydrotest pressure requirement of process line given in B31.3 below 1.5 in any case? Someone sent me this

(When performing a hydrostatic test on a piping system, it is important to ensure that the test pressure does not exceed the pressure rating of the piping system or the pressure-retaining components. The pressure rating of a piping system is the maximum pressure that the system is designed to safely contain. The pressure rating of a pressure-retaining component, such as a valve or flange, is the maximum pressure that the component is designed to withstand.
If the hydrostatic test pressure exceeds the pressure rating of the piping system or a pressure-retaining component, there is a risk of over-pressurization, which can result in damage or failure of the system. Over-pressurization can cause deformation, cracking, or even rupturing of the piping system, leading to leaks or even catastrophic failure. Therefore, to ensure the safety and integrity of the piping system, it is crucial to carefully monitor the test pressure and to ensure that it does not exceed the pressure rating of the system or its components)

and saying 1.5 is not mandatory but I think code sticks to 1.5 times.
Thanks

 

[Krausen]

Atm lines are not required to be hydro-ed to 1.5xDesign Pressure under B31.3. You have some wiggle room here.

 

[SmallInfo]

Thanks Krausen
Then what is minimum requirement for atm line test?

 

[1503-44]

B31.3 (2014 edition)
You should check newest editions or the edition specified for your design)

B31.3 does not cover pressure less than 15psia, if the fluid handled is nonflammable, nontoxic, and not damaging to human tissues as defined in 300.2, and its design temperature is from −29°C (−20°F) through 186°C (366°F), as stated in 300.1.3 Exclusions.

A pipe operating at less than 15psia is subject to external pressure, hence 345.2.4 applies.

345.2.4 Externally Pressured Piping. Piping subject
to external pressure shall be tested at an internal gage
pressure 1.5 times the external differential pressure, but
not less than 105 kPa (15 psi).

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[r6155]

What inspection and NDE did you consider before the hydrostatic test?
The pressure for the test must be agreed between the manufacturer and the user.

Regards

 

[GBTorpenhow]

B31.3 does not cover pressure less than 15psia...

A minor clarification, the code scope exemption pressure is 15 psi gauge, not absolute.

SmallInfo, even if the code scope exemption referenced for "nonflammable, nontoxic..." based on pressures and temps is not activated, lines open to atmosphere downstream of the last valve are not required to be pressure tested by B31.3 2020 §345.1(d).

While not required by code, depending on the fluid handled and situation it may be prudent by your own engineering judgement to dictate in the design a basic leak check using air & soap at 15-25 psig or similar to confirm the lack of major leak paths.

 

[SmallInfo]

1503-44, r6155, GBTorpenhow
Thank you all its clear now.
I am posting another question you all are requested to look at it as well.
Thanks again

 

[Krausen]

Thanks Krausen
Then what is minimum requirement for atm line test?

There is no minimum requirement in this case, the code exempts you from the hydrotest. Although you can always go above & beyond as mentioned above. You may get laughed at by the contractor or management though if you do. I've never seen an atm line hydrotested to 1.5xDP before.

 

[1503-44]

GBT, Thank you. Yes the OP said atmospheric. Code reference is gage. Outcome unchanged.

Krausen, I read the minimum as 15 psig.


If anyone laughs, offer to run an H2S pipe through their office.

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[r6155]

Some test must be done.
At a minimum fill with water and inspect for leaks.
Neither test appears to be bad engineering practice.

Regards

 

[SmallInfo]

Thank you everyone, it really helped me make my mind clear.