###### Editorial Note on [Part 250](/current/title-30/part-250?toc=1)

#### Editorial Note:

Nomenclature changes to part 250 appear at [77 FR 50891](https://www.federalregister.gov/citation/77-FR-50891), Aug. 22, 2012.

#### § 250.851 Pressure vessels (including heat exchangers) and fired vessels.

(a) Pressure vessels (including heat exchangers) and fired vessels supporting production operations must meet the requirements in the following table:

| Item name | Applicable codes and requirements |
| --- | --- |
| (1) Pressure and fired vessels | (i) Must be designed, fabricated, and code stamped according to applicable provisions of sections I, IV, and VIII of the ANSI/ASME Boiler and Pressure Vessel Code (incorporated by reference as specified in [§ 250.198](/on/2024-09-16/title-30/section-250.198)). (ii) Must be repaired, maintained, and inspected in accordance with API 510 (incorporated by reference as specified in [§ 250.198](/on/2024-09-16/title-30/section-250.198)). |
| (2) Existing uncoded pressure and fired vessels: | Must be justified and approval obtained from the District Manager for their continued use. |
| (i) With an operating pressure greater than 15 psig; and | |
| (ii) That are not code stamped in accordance with the ASME Boiler and Pressure Vessel Code | |
| (3) Pressure relief valves | (i) Must be designed and installed according to applicable provisions of sections I, IV, and VIII of the ASME Boiler and Pressure Vessel Code (incorporated by reference as specified in [§ 250.198](/on/2024-09-16/title-30/section-250.198)). (ii) Must conform to the valve sizing and pressure-relieving requirements specified in these documents, but must be set no higher than the maximum-allowable working pressure of the vessel (except for cases where staggered set pressures are required for configurations using multiple relief valves or redundant valves installed and designated for operator use only). (iii) Vents must be positioned in such a way as to prevent fluid from striking personnel or ignition sources. |
| (4) Steam generators operating at less than 15 psig | Must be equipped with a level safety low (LSL) sensor which will shut off the fuel supply when the water level drops below the minimum safe level. |
| (5) Steam generators operating at 15 psig or greater | (i) Must be equipped with a level safety low (LSL) sensor which will shut off the fuel supply when the water level drops below the minimum safe level. (ii) Must be equipped with a water-feeding device that will automatically control the water level except when closed loop systems are used for steam generation. |

(b) *Operating pressure ranges.* You must use pressure recording devices to establish the new operating pressure ranges of pressure vessels at any time that the normalized system pressure changes by 50 psig or 5 percent. Once system pressure has stabilized, pressure recording devices must be utilized to establish the new operating pressure ranges. The pressure recording devices must document the pressure range over time intervals that are no less than 4 hours and no more than 30 days long. You must maintain the pressure recording information you used to determine current operating pressure ranges at your field office nearest the OCS facility or at another location conveniently available to the District Manager for as long as the information is valid.

(c) Pressure shut-in sensors must be set according to the following table (initial set points for pressure sensors must be set utilizing gauge readings and engineering design):

| Type of sensor | Settings | Additional requirements |
| --- | --- | --- |
| (1) High pressure shut-in sensor, | Must be set no higher than 15 percent or 5 psi (whichever is greater) above the highest operating pressure of the vessel | Must also be set sufficiently below (5 percent or 5 psi, whichever is greater) the relief valve's set pressure to assure that the pressure source is shut-in before the relief valve activates. |
| (2) Low pressure shut-in sensor, | Must be set no lower than 15 percent or 5 psi (whichever is greater) below the lowest pressure in the operating range | You must receive specific approval from the District Manager for activation limits on pressure vessels that have a pressure safety low (PSL) sensor set less than 5 psi. |

[[76 FR 64462](https://www.federalregister.gov/citation/76-FR-64462), Oct. 18, 2011, as amended at [84 FR 24706](https://www.federalregister.gov/citation/84-FR-24706), May 29, 2019]