A colleague of mine was asked to verify the size of a relief valve designed for a heat exchanger failure. The heat exchanger is a brazed aluminum plate fin exchanger. The high pressure side (gas) is rated for 1100 psig, while the low pressure side (liquid) is rated for 400 psig. There is currently a relief valve on the liquid outlet that is supposed to protect a downstream pump from overpressuring if 1100 psig gas leak into the liquid section.
We aren't really sure how they determined a leak size for the original calculation, and we can't find any documentation. We didn't find any guidance in API regarding this type of exchanger failure. Is there another reference that might provide some guidance on this case? Thank you.