Relief Valve Capacity Verifier

Compares nameplate certified capacity of pressure-relief valves against API 520 Part 1 (Eq. 3.2, gas/vapor) required capacity, and flags any installation undersized for its contingency. Required columns: tag, service, W_lbhr, MW, T_F, Z, k, P_set_psig, accum_frac, backpressure_psig, has_rupture_disc, cert_orifice_letter, cert_area_in2, Kd.

CSV Input

Method: API 520 Part 1 (10th Ed., 2020) Eq. 3.2 vapor sizing — A = W / (C·K_d·K_b·K_c·P₁) · √(T·Z/M), with C = 520·√(k·(2/(k+1))^{(k+1)/(k−1)}) and P₁ = P_set·(1+accumulation) + 14.696 psia. K_b from a conservative linear approximation to API 520 Fig. 30 above P_b/P_set = 0.3 (conventional valve); K_c = 0.9 with rupture disc, 1.0 without. Required orifice letter selected from API 526 (8th Ed., 2023) effective-area table; result is PASS if certified effective area ≥ required area. Limitation: gas/vapor only (liquid and 2-phase per API 520 §5.7 / DIERS not implemented).

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