#### § 56.04-2 Piping classification according to service.

The designation of classes according to service is found in table 1 to [§ 56.04-2](/on/2024-09-23/title-46/section-56.04-2).

Table 1 to [§ 56.04-2](/on/2024-09-23/title-46/section-56.04-2)—Pressure Piping Classification

| Service | Class1 | Pressure (p.s.i.g.) | | Temp. (°F) |
| --- | --- | --- | --- | --- |
| Class B and C poisons2 | I | any | and | 0 and above. |
| | I-L | any | and | below 0. |
| | II | (3 ) | (3 ) | (3 ) |
| | II-L | (3 ) | (3 ) | (3 ) |
| Gases and vapors2 | 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 gases2 | 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 D2 | 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](/on/2024-09-23/title-46/part-40). |
| Other dangerous cargoes. | Refer to specific requirements of [part 98 of this chapter](/on/2024-09-23/title-46/part-98). |
| | |
| --- | --- |
| 1 Where doubt exists as to proper classification, refer to the Commandant for resolution. | |
| 2 For definitions, see [parts 30](/on/2024-09-23/title-46/part-30), [151](/on/2024-09-23/title-46/part-151), and [154 of this chapter](/on/2024-09-23/title-46/part-154). Note that the category “B and C” poisons is not used in the rules applying to self-propelled vessels ([part 153 of this chapter](/on/2024-09-23/title-46/part-153)). | |
| 3 Not permitted except inside cargo tanks approved for Class B and C poisons. | |

[CGFR 68-82, [33 FR 18843](https://www.federalregister.gov/citation/33-FR-18843), Dec. 18, 1968, as amended by CGD 73-254, [40 FR 40164](https://www.federalregister.gov/citation/40-FR-40164), Sept. 2, 1975; CGD 73-96, [42 FR 49024](https://www.federalregister.gov/citation/42-FR-49024), Sept. 26, 1977; USCG-2020-0634, [89 FR 50131](https://www.federalregister.gov/citation/89-FR-50131), June 12, 2024]