Saucerito
Mechanical
- Dec 1, 2014
- 11
Hi,
I'd like to know if it is necessary/practical to use ASME PCC-2 Mandatory Appendix II - Stored Energy Calculations for Pneumatic Pressure Test for pneumatic leak testing of equipment that has already been hydrotested in the shop.
Background:
[li]Loop Reactor with flanged/gasketed joints.[/li]
[li]MAWP: 740psig[/li]
[li]Material: Carbon Steel[/li]
[li]Reactor components have been hydrostatically tested in shop[/li]
The site would like to pneumatically leak test the reactor with N2 to 638psig to prove flanged/gasketed joints are properly sealing before introducing hydrocarbons. We were asked to provide a blast radius for the test. Per PCC2, this will result in a radius of over 600'.
[ol 1]
[li]Is it necessary to define a blast radius when hydrostatic testing has already been completed successfully?[/li]
[li]In terms of potential consequences, is there a difference between this proposed leak test and starting up an identical, existing pressure vessel at 638psig (in N2 service) after maintenance has disconnected and reconnected flanges?[/li]
[/ol]
What I'm getting at is if a vessel has been hydro-tested, what is the point of setting up a blast radius for a pneumatic leak test? The integrity of the materials have already been tested, and in my mind the only risk is for a blown out gasket (and maybe N2 displacement of O2 if personnel are nearby). If a blown out gasket is that much of risk, then shouldn't we always have a blast radius barricaded off when starting up equipment after maintenance has disconnected/reconnected flanges?
What am I missing here?
Thanks, Will
I'd like to know if it is necessary/practical to use ASME PCC-2 Mandatory Appendix II - Stored Energy Calculations for Pneumatic Pressure Test for pneumatic leak testing of equipment that has already been hydrotested in the shop.
Background:
[li]Loop Reactor with flanged/gasketed joints.[/li]
[li]MAWP: 740psig[/li]
[li]Material: Carbon Steel[/li]
[li]Reactor components have been hydrostatically tested in shop[/li]
The site would like to pneumatically leak test the reactor with N2 to 638psig to prove flanged/gasketed joints are properly sealing before introducing hydrocarbons. We were asked to provide a blast radius for the test. Per PCC2, this will result in a radius of over 600'.
[ol 1]
[li]Is it necessary to define a blast radius when hydrostatic testing has already been completed successfully?[/li]
[li]In terms of potential consequences, is there a difference between this proposed leak test and starting up an identical, existing pressure vessel at 638psig (in N2 service) after maintenance has disconnected and reconnected flanges?[/li]
[/ol]
What I'm getting at is if a vessel has been hydro-tested, what is the point of setting up a blast radius for a pneumatic leak test? The integrity of the materials have already been tested, and in my mind the only risk is for a blown out gasket (and maybe N2 displacement of O2 if personnel are nearby). If a blown out gasket is that much of risk, then shouldn't we always have a blast radius barricaded off when starting up equipment after maintenance has disconnected/reconnected flanges?
What am I missing here?
Thanks, Will
