(b) Oxygen fuel gas welding is not permitted on flammable fluid piping with a service temperature below -29 degrees C (-20 degrees F).
(c) Marking materials for identifying welds on pipe must be compatible with the basic pipe material.
(d) Surfaces of components that are less than 6.35 mm (0.25 in.) thick may not be field die stamped.
(e) Where die stamping is permitted, any identification marks must be made with a die having blunt edges to minimize stress concentration.
[45 FR 9203, 11, 1980, as amended at 47 FR 32720, July 29, 1982; 47 FR 33965, Aug. 5, 1982]
193.2315 Piping connections.
(a) Piping more than 2 inches nominal diameter must be joined by welding, except that --
(1) Threaded or flanged connections may be used where necessary for special connections, including connections for material transitions, instrument connections, testing, and maintenance;
(2) Copper piping in nonflammable service may be joined by silver brazing; and
(3) Material transitions may be made by any joining technique proven reliable under §193.2305(b).
(b) If socket fittings are used, a clearance of 1.6 to 3.2 mm (0.063 to 0.126 in.) between the pipe end and the bottom of the socket recess must be provided and appropriate measurement reference marks made on the piping for the purpose of inspection.
(c) Threaded joints must be --
(1) Free of stress from external loading; and
(2) Seal welded, or sealed by other means which have been tested and proven reliable.
(d) Compression type couplings must meet the requirements of ASME/ANSI B31.3.
(e) Care shall be taken to ensure the tightness of all bolted connections. Spring washers or other such devices designed to compensate for the contraction and expansion of bolted connections during operating cycles shall be used where required.
(f) The selection of gasket material shall include the consideration of fire.
[58 FR 14522, March 18, 1993]
193.2317 Retesting.
After testing required by this subpart is completed on a component to contain a hazardous fluid, the component must be retested whenever --
(a) Penetration welding other than tie-in welding is performed; or
(b) The structural integrity of the component is disturbed.
193.2319 Strength tests.
(a) A strength test must be performed on each piping system and container to determine whether the component is capable of performing its design function, taking into account --
(1) The maximum allowable working pressure;
(2) The maximum weight of product which the component may contain or support;
(b) For piping, the test required by paragraph (a) of this section must include a pressure test conducted in accordance with section 345 of ASME/ANSI B31.3, except that test pressures must be based on the design pressure. Carbon and low alloy steel piping must be pressure tested above their nil ductility transition temperature.
(c) All shells and internal parts of heat exchangers to which section VIII, Division 1, or Division 2 of the ASME Boiler and Pressure Vessel Code, applies must be pressure tested, inspected, and stamped in accordance therewith.
[58 FR 14522, March 18, 1993]
193.2321 Nondestructive tests.
(a) The following percentages of each day's circumferentially welded pipe joints for hazardous fluid piping, selected at random, must be nondestructively tested over the entire circumference to indicate any defects which could adversely affect the integrity of the weld or pipe:
-
See PDF for table 
(b) Evaluation of weld tests and repair of defects must be in accordance with the requirements of ASME/ANSI B31.3 or API 1104, as applicable.
(c) Where longitudinally or spiral welded pipe is used in transfer systems, 100 percent of the seam weld must be examined by radiographic or ultrasonic inspection.
(d) The butt welds in metal shells of storage tanks with internal design pressure of not more than 15 psig must be radiographically tested in accordance with section Q.7.6, API 620, Appendix Q, except that for hydraulic load bearing shells with curved surfaces that are subject to cryogenic temperatures, 100 percent of both longitudinal (or meridional) and circumferential or (or latitudinal) welds must be radiographically tested.
(e) The butt welds in metal shells of storage tanks with internal design pressure above 15 psig must be radiographically tested in accordance with section IX of the ASME Boiler and Pressure Vessel Code, except that for hydraulic load bearing shells with curved surfaces that are subject to cryogenic temperatures, 100 percent of both longitudinal (or meridional) and circumferential (or latitudinal) welds must be radiographically tested.
[58 FR 14522, March 18, 1993; Amdt. 193-10, 61 FR 18517, April 26, 1996]
193.2323 Leak tests.
(a) Each container and piping system must be initially tested to assure that the component will contain the product for which it is designed without leakage.
(b) Shop fabricated containers and all flammable fluid piping must be leak tested to a minimum of the design pressure after installation but before placing it in service.
(c) For a storage tank with vacuum insulation, the inner container, outer shell, and all internal piping must be tested for vacuum leaks in accordance with an appropriate procedure.
193.2325 Testing control systems.
Each control system must be tested before being placed in service to assure that it has been installed properly and will function as required by this part.
193.2327 Storage tank tests.
(a) In addition to other applicable requirements of this subpart, storage tanks for cryogenic fluids with internal design pressures of not more than 15 psig must be tested in accordance with sections Q8, Q9, and Q10 of API 620, appendix Q, as applicable.
(b) Metal storage tanks for cryogenic fluids with internal design pressures above 15 psig must be tested in accordance with the applicable division of section VIII of the ASME Boiler and Pressure Vessel Code.
(c) Reference measurements must be made with appropriate precise instruments to assure that the tank is gas tight and lateral and vertical movement of the storage tank does not exceed predetermined design tolerances.
[58 FR 14522, March 18, 1993]
193.2329 Construction records.
For the service life of the component concerned, each operator shall retain appropriate records of the following:
(a) Specifications, procedures, and drawings prepared for compliance with 193.2305; and
(b) Results of tests, inspections, and the quality assurance program required by this subpart.
