UPDATE NEW ASME BPVC SECTION XIII - RULES FOR OVERPRESSURE PROTECTION (JULY 2021)
This new XIII section of the BPVC was originally scheduled to replace earlier Overpressure Protection Requirements in BPVC Sections I, III, IV, & VIII.
Initial review of Section XIII informs that Overpressure Protection Requirements for ASME BPVC Sections I (Power Boilers) & III (Nuclear) will remain in new 2021 edition of I & III with the exception of their capacity testing and certification requirements, which will be in the new Section XIII.
New ASME BPVC Sections IV (Hot Water Boilers) & VIII (Unfired Pressure Vessels) 2021 editions have deleted earlier Overpressure Protection Requirements and now refer user to new Section XIII.
Since earlier Sections I, III, IV & VIII are now effectively under new Section XIII, Distinction between those earlier code sections is apparently done by the 'Certification Mark & designator' eg. 'V' (was ASME I), 'NV-1' (was ASME III), 'UV' (was ASME VIII) etc. I guess in time the industry, manufacturers and users, will settle how this is represented.
Section XIII is specific in its scope that it only applies to the PRD's from inlet to outlet (as a PRD item only), hence piping, determination of set pressures etc., remain in the 'Referenced Code'. Furthermore, should any requirement in XIII be in conflict, it is stated that the 'Referenced Code' shall take precedence.
There are other differences since the new section XIII is essentially harmonising several earlier sections. Like other BPVC Sections, new editions will be every two years.
*** Per ISO-4126, the generic term 'Safety Valve' is used regardless of application or design ***
*** 'Pressure-relief Valve' is the equivalent ASME/API term ***