TrevorP
Chemical
- Mar 25, 2002
- 142
I recently sized a relief device for the fire case for an existing vessel using API520. The relief device manufacturer came back to me and advised that the relief device I had specified was sized wrongly according to API 2000. As it turns out, he was right, since the set pressure was below 15 psig. However, this got me looking at the difference between the two standards - surely they cover the same ground (excluding pressure), so shouldn't they be seamless between 14.99 psig and 15 psig??
It appears that they are not - API 2000 has different equations based on the heat input from a fire (It appears to be more comprehensive). One other area of contention is that the conversion factor from kg/hr to scfh is curious to say the least (I supplied a kg/hr figure to the manufacturer based on Q/l and the manufacturer converted from there - this did not tie in with API 2000's direct calculation for SCFH). Needless to say, I accepted the manufacturer's sizing, however I do find the differences to be curious.
I accept that I may not be using the latest version of either of the standards so may require an upgrade, but can anyone shed any light on the apparent above discrepancies?
It appears that they are not - API 2000 has different equations based on the heat input from a fire (It appears to be more comprehensive). One other area of contention is that the conversion factor from kg/hr to scfh is curious to say the least (I supplied a kg/hr figure to the manufacturer based on Q/l and the manufacturer converted from there - this did not tie in with API 2000's direct calculation for SCFH). Needless to say, I accepted the manufacturer's sizing, however I do find the differences to be curious.
I accept that I may not be using the latest version of either of the standards so may require an upgrade, but can anyone shed any light on the apparent above discrepancies?
