CFR > Title 46 - Shipping > CHAPTER I—COAST GUARD, DEPARTMENT OF HOMELAND SECURITY > SUBCHAPTER F—MARINE ENGINEERING (parts 50 to 64) > PART 56—PIPING SYSTEMS AND APPURTENANCES > SUBPART 56.04—Piping Classification (§56.04-1 to §56.04-10) > 56.04-2—Piping classification according to service.

56.04-2—Piping classification according to service.

The designation of classes according to service is found in Table 56.04-2.
Table 56.04-2—Pressure Piping Classification
Service Class 1 Pressure (p.s.i.g.) Temp. (°F)
Class B and C poisons 2 I any and 0 and above.
I-L any and below 0.
II (3 ) (3 ) (3 )
II-L (3 ) (3 ) (3 )
Gases and vapors 2 I above 150 or above 650.
I-L above 150 and below 0.
II 150 and below and 0 to 650.
II-L 150 and below and below 0.
Liquefied flammable gases 2 I above 150 and 0 and above. 1
I-L above 150 and below 0.
II 150 and below and 0 and above.
II-L 150 and below and below 0.
Molten sulphur I above 225 or above 330.
II 225 and below and 330 and below.
Cargo liquids Grades A through D 2 I above 225 or above 150.
I-L above 225 and below 0.
II 225 and below and 0 to 150.
II-L 225 and below and below 0.
Cargo liquids Grade E I above 225 or above 400.
I-L above 225 and below 0.
II 225 and below and 0 to 400.
II-L 225 and below and below 0.
Water I above 225 or above 350.
II 225 and below and 350 and below.
Fuels (Bunker, diesel, gasoline, etc.) I above 150 or above 150.
II 150 and below and 150 and below.
Lubricating oil I above 225 or above 400.
II 225 and below and 400 and below.
Asphalt I above 225 or above 400.
II 225 and below and 400 and below.
Heat transfer oil I above 225 or above 400.
II 225 and below and 400 and below.
Code of Federal Regulations 176
Hydraulic fluid I above 225 or above 400.
II 225 and below and 400 and below.
Flammable or combustible dangerous cargoes. Refer to specific requirements of part 40 of this chapter .
Other dangerous cargoes. Refer to specific requirements of part 98 of this chapter .
1 Where doubt exists as to proper classification, refer to the Commandant for resolution.
2 For definitions, see 46 CFR parts 30, 151, and 154 . Note that the category “B and C” poisons is not used in the rules applying to self-propelled vessels (46 CFR part 153 ).
3 Not permitted except inside cargo tanks approved for Class B and C poisons.
[CGFR 68-82, 33 FR 18843, Dec. 18, 1968, as amended by CGD 73-254, 40 FR 40164, Sept. 2, 1975; CGD 73-96, 42 FR 49024, Sept. 26, 1977]