Regulations last checked for updates: Oct 17, 2024

Title 46 - Shipping last revised: Oct 15, 2024
§ 56.04-2 - Piping classification according to service.

The designation of classes according to service is found in table 1 to § 56.04-2.

Table 1 to § 56.04-2—Pressure Piping Classification

Service Class 1 Pressure (p.s.i.g.) Temp. (°F)
Class B and C poisons 2Ianyand0 and above.
I-Lanyandbelow 0.
II( 3 )( 3 )( 3 )
II-L( 3 )( 3 )( 3 )
Gases and vapors 2Iabove 150orabove 650.
I-Labove 150andbelow 0.
II150 and belowand0 to 650.
II-L150 and belowandbelow 0.
Liquefied flammable gases 2Iabove 150and0 and above. 1
I-Labove 150andbelow 0.
II150 and belowand0 and above.
II-L150 and belowandbelow 0.
Molten sulphurIabove 225orabove 330.
II225 and belowand330 and below.
Cargo liquids Grades A through D 2Iabove 225orabove 150.
I-Labove 225andbelow 0.
II225 and belowand0 to 150.
II-L225 and belowandbelow 0.
Cargo liquids Grade EIabove 225orabove 400.
I-Labove 225andbelow 0.
II225 and belowand0 to 400.
II-L225 and belowandbelow 0.
WaterIabove 225orabove 350.
II225 and belowand350 and below.
Fuels (Bunker, diesel, gasoline, etc.)Iabove 150orabove 150.
II150 and belowand150 and below.
Lubricating oilIabove 225orabove 400.
II225 and belowand400 and below.
AsphaltIabove 225orabove 400.
II225 and belowand400 and below.
Heat transfer oilIabove 225orabove 400.
II225 and belowand400 and below.
Hydraulic fluidIabove 225orabove 400.
II225 and belowand400 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 parts 30, 151, and 154 of this chapter. Note that the category “B and C” poisons is not used in the rules applying to self-propelled vessels (part 153 of this chapter).

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; USCG-2020-0634, 89 FR 50131, June 12, 2024]
authority: 33 U.S.C. 1321(j), 1509; 43 U.S.C. 1333; 46 U.S.C. 3306,3703; E.O. 12234, 45 FR 58801, 3 CFR, 1980 Comp., p. 277; E.O. 12777, 56 FR 54757, 3 CFR, 1991 Comp., p. 351; Department of Homeland Security Delegation No. 00170.1, Revision No. 01.3
source: CGFR 68-82, 33 FR 18843, Dec. 18, 1968, unless otherwise noted.
cite as: 46 CFR 56.04-2