Weighted relief device on the blower

[SM2K]

Greeting!

I have come accross some weighted relief devices, which are more like pressure vents with weights. It lists some different manufacturers like Roots and Metal Arts. All I know is the size (8", 10" etc)and capacities on few of them. They are set below 15 psig pressure. I am confused as to use API 520 or API 2000 or some other standards. If anyone has ever come accross such vents please guide me on this issue.

Regards,

Sunil Mishra

 

[EGT01]

Sunil Mishra,

Just to offer some general comments, you need to look beyond just your relief device and evaluate the system that it is intended protect.

Typically, API RP-520 are practices that are followed when evaluating equipment such as pressure vessels, those rated for greater than 15 psig and designed per ASME Sec VIII. API 2000 are practices that are followed when evaluating equipment such as atmospheric or low pressure storage tanks, those designed per API 650 or API 620.

There could be other standards to which the equipment you are protecting have been constructed. Knowing the limits of the equipment design is necessary to assess whether the relief device can be set at the MAWP and allow a pressure increase above MAWP when evaluating the relief device capacity. Otherwise, you may be required to have the set pressure below MAWP so that the MAWP is never exceeded during a relief case.

You also need to clearly identify your relief device in order to properly assess its capacity. If it is stamped with a capacity, that is good to know but I would want to review the manufacturer's information about how that capacity was determined or how the manufacturer recommends assessing the device's capacity.

 

[psafety]

Sunil Mishra,
I've seen where blower manufacturers have typically supplied these weighted reliefs to protect their equipment from dead-head conditions. I've seen them for positive as well as negative pressure applications.

don Coffman