API 526 7th pdf download Flanged Steel Pressure-relief Valves 7.4Dimensions Center-to-face dimensions shall be in accordance with Table 3 through Table 16 for spring-loaded valves andTable 16 through Table 29 for pilot-operated valves, with tolerances of±11s in. for valve inlet sizes up to and including4 in., and +1/8 in. for valve inlet sizes larger than 4 in. Flange facings and...