Search results for query: *

don1980, Thank you for your post. This issue of set pressure being different than MAWP has made me evaluate the way I look at PSV sizing. I want to have a high level of confidence that what I am doing is right, whether it is evaluating credible scenarios and their flow rates, or plugging in...

Sorry for posting again so quickly, I wasn't sure how to edit my original post. I just wanted to say that preliminary calcs show the existing valve to be way undersized if we use a 535 psia relieving pressure (and the associated very small heat of vaporization). It would be great if we could...

Here's what I've got: Tank MAWP = 430 psig; Existing PSV set pressure = 420 psig; Critical Pressure of contents (F-404a) = 541.2 psia; Sizing Scenario = Fire Case (F-404a is not flammable, but client wants to see the calcs). OK, so here's my question: How is the relieving pressure calculated...

elquesifilma, I struggled with figuring out how to do the exact same type of capacity conversion not all that long ago. Of course, you should have no trouble converting from say, SCFM air to lb/min of air; this simply involves using the ideal gas equation, substituting in pressure (1 atm)...

Wow, there's some good discussion going on above. If I had to summarize it, I would say, "It's up to the user to decide whether to size a PSV on a pressure vessel for the fire case." Thankfully, the above posts go beyond just saying this, and give "the user" some things to consider when...

Right, fire can generally be disregarded for wetted surfaces > 25 ft above any structure that can support a pool fire. And YES, I would say that the fire scenario can be disregarded if you can argue that fire could "never" occur. In the case of especially volatile flammable refrigerants, I...

I must admit that I am not familiar with ASHRAE standards but, as zdas04 points out, they seem to be geared toward end-users of heating and refrigeration equipment and especially those designing such equipment. In our case, the client is manufacturing and storing refrigerants on-site. Due to...

In order to make consistent recommendations to the client concerning required PSV size, would it be good to establish a criteria for performing fire analysis based on the difference between refrigerant boiling point and lowest expected ambient temperature? Something like: If (Min. Expected...

Yes, sizing the PSV on a propane tank for fire is the exact same example that a fellow engineer used when I asked him about this issue-and it makes sense. At the same time, in this plant, the PSVs on a couple of R-32 tanks (similar to propane in that it is flammable and has a similar boiling...

Thanks for the replies RaRo and zdas04. We have been assuming that there is a chance for a flammable refrigerant leak to occur with subsequent ignition; the main contention has been with the pooling issue. Just to clarify, each refrigerant is stored separately, in nearly pure form. The lowest...

I am currently working with a client to document and review existing pressure-relieving devices per API standards. This particular plant manufactures a variety of both flammable and non-flammable refrigerants, which are stored in 10,000+ gallon tanks. My question is this: Should the pressure...