Super Capacity Pressure Relief Valves 1

[molechaser]

FARRIS markets some super capacity PRV's with orifice sizes designated at U (31.5 in2), W, W2, X,Y,Z (176.7 in2).

Does anyone have experience with these ?
Are they acceptable? Do they meet codes?
What are the pros and cons?

We have a light hydrocarbon application with a set pressure of 50 psig that requires 17 8T10 conventional valves. Could a few of these larger PRV's be used as an alternative?

 

[greenche]

We use Farris valves extensively, mainly the 2600 series you are referring to. No specific experience with the super capacity valves, but the main drawback I see is weight. Those things are heavy! Otherwise, they are built to ASME Section VIII and capacity certified. Acceptability beyond that has to be defined by the user.

 

[molechaser]

Thanks for the information.

I agree that the weight is a consideration but the large number of 'T' size valves is more of a concern for us. We have used rupture-pin (Callidus) and buckling-pin (BS&B) devices in another installation and these are also very large and weighty. This is fairly inevitable (given the capacity requirements) if you are going to use fewer devices. The other devices have their own installation and maintenance issues, so there may be some preference to stay with the more widely accepted design of a much larger standard spring loaded valve.

 

[PMarinshaw]

I have over twenty years previous experience with the super capacity valves - not from Farris in particular but rather with Lonergan and Crosby. Other than the weight and long leadtime for parts, there is nothing to be concerned about using these. If these ever have to discharge in gas or vapor service they produce one hell of a thrust (I seen one blow down a chain link fence 40 feet away), so be sure the discharge piping is well designed to handle it.