Preliminary pressure-relief device orifice area for gas/vapor or liquid service using API 520 Part I sizing equations. Use only for early screening of relief loads, comparing scenarios, and sanity-checking vendor sizing. Don't use for final design (which requires the authoritative API 520/521/526 text and qualified relief engineering), for two-phase / flashing relief (DIERS methodology), or for fire-case relief load development (use API 521 to establish the load first).
