46 CFR § 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 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.
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 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]