Using Rupture Disc Instead of Safety Relief Valve 1

[SimStil]

The project I'm working on involves designing the piping system for a reciprocating compressor test rig - only clean air will be used as the medium. For the compressor packages safety relief valves are used, however I am trying to see if there is any reason why a rupture disk cannot be used instead as a cheaper alternative. We will have alarms and trips in place as standard and so we don't expect the pressure relieving device to ever be in use all going well. In the unlikely event of a high enough pressure to activate the device, we would not incur any financial penalties from the downtime required to replace the rupture disc for subsequent testing.

Also worth noting,
[ul]
[li]the valve/disc discharge would be re-routed within the system - no exposure to the atmosphere.[/li]
[li]some level of air pulsation will be present from the compressor discharge - fatigue risk?[/li]
[/ul]

Could you please share your wisdom and tell me why using a rupture disc vs. a safety relief valve would not be a good idea?

 

[LittleInch]

Have a hunt around on the safety relief valve forum and you'll find more answers there.

In general you want to use a bursting disc for
[ul]
[li]non pulsating service
[/li]
[li]Where you never really expect the pressure to climb
[/li]
[li]where the bits of the disc can't cause a problem to anything downstream[/li]
[li]Where sudden reduction in pressure is not an issue[/li]
[li]Where not using a relief valve makes good sense[/li]
[li]Where you need almost instantaneous operation faster than a valve can provide[/li]
[/ul]

I don't think you have any of those and this is a wholly bad idea IMHO
It might initially be cheaper than a relief valve, but not once you factor in the time and effort you will need to replace the wretched thing on a regular basis with downtime, risk of damage to the compressor, replacement time, cost of the bursting disc etc.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[moltenmetal]

In addition to LittleInch's excellent list above, or perhaps clarifying his 2nd last bullet point:

- where leakage is not tolerated, but re-closure after a relief event isn't essential either

If reclosure after a relief event is required, you need a nonfragmenting rupture disk, a disk leakage detection means, and a relief valve AFTER the disk.