49 CFR 172 Special Provisions – TP-Codes
These provisions apply to the transportation of hazardous materials in IM and UN Specification portable tanks.
| Code | Description | |
|---|---|---|
| TP1 | The maximum degree of filling must not exceed the degree of filling determined by the following:  Where: tr is the maximum mean bulk temperature during transport, and tf is the temperature in degrees celsius of the liquid during filling. | Browse TP1 |
| TP2 | a. The maximum degree of filling must not exceed the degree of filling determined by the following:  Where: tr is the maximum mean bulk temperature during transport, tf is the temperature in degrees celsius of the liquid during filling, and α is the mean coefficient of cubical expansion of the liquid between the mean temperature of the liquid during filling (tf) and the maximum mean bulk temperature during transportation (tr) both in degrees celsius. b. For liquids transported under ambient conditions α may be calculated using the formula:  Where: d15 and d50 are the densities (in units of mass per unit volume) of the liquid at 15 °C (59 °F) and 50 °C (122 °F), respectively. | Browse TP2 |
| TP3 | The maximum degree of filling (in %) for solids transported above their melting points and for elevated temperature liquids shall be determined by the following: Where: df and dr are the mean densities of the liquid at the mean temperature of the liquid during filling and the maximum mean bulk temperature during transport respectively. | Browse TP3 |
| TP4 | The maximum degree of filling for portable tanks must not exceed 90%. | Browse TP4 |
| TP5 | For a portable tank used for the transport of flammable refrigerated liquefied gases or refrigerated liquefied oxygen, the maximum rate at which the portable tank may be filled must not exceed the liquid flow capacity of the primary pressure relief system rated at a pressure not exceeding 120 percent of the portable tank's design pressure. For portable tanks used for the transport of refrigerated liquefied helium and refrigerated liquefied atmospheric gas (except oxygen), the maximum rate at which the tank is filled must not exceed the liquid flow capacity of the pressure relief device rated at 130 percent of the portable tank's design pressure. Except for a portable tank containing refrigerated liquefied helium, a portable tank shall have an outage of at least two percent below the inlet of the pressure relief device or pressure control valve, under conditions of incipient opening, with the portable tank in a level attitude. No outage is required for helium. | Browse TP5 |
| TP6 | The tank must be equipped with a pressure release device which prevent a tank from bursting under fire engulfment conditions (the conditions prescribed in CGA pamphlet S-1.2 (see §171.7 of this subchapter) or alternative conditions approved by the Associate Administrator may be used to consider the fire engulfment condition), taking into account the properties of the hazardous material to be transported. | Browse TP6 |
| TP7 | The vapor space must be purged of air by nitrogen or other means. | Browse TP7 |
| TP8 | A portable tank having a minimum test pressure of 1.5 bar (150 kPa) may be used when the flash point of the hazardous material transported is greater than 0 °C (32 °F). | Browse TP8 |
| TP9 | A hazardous material assigned to special provision TP9 in Column (7) of the §172.101 Table may only be transported in a portable tank if approved by the Associate Administrator. | Browse TP9 |
| TP10 | The portable tank must be fitted with a lead lining at least 5 mm (0.2 inches) thick. The lead lining must be tested annually to ensure that it is intact and functional. Another suitable lining material may be used if approved by the Associate Administrator. | Browse TP10 |
| TP12 | This material is considered highly corrosive to steel. | Browse TP12 |
| TP13 | Self-contained breathing apparatus must be provided when this hazardous material is transported by sea. | Browse TP13 |
| TP16 | The portable tank must be protected against over and under pressurization which may be experienced during transportation. The means of protection must be approved by the approval agency designated to approve the portable tank in accordance with the procedures in part 107, subpart E, of this subchapter. The pressure relief device must be preceded by a frangible disk in accordance with the requirements in §178.275(g)(3) of this subchapter to prevent crystallization of the product in the pressure relief device. | Browse TP16 |
| TP17 | Only inorganic non-combustible materials may be used for thermal insulation of the tank. | Browse TP17 |
| TP18 | The temperature of this material must be maintained between 18 °C (64.4 °F) and 40 °C (104 °F) while in transportation. Portable tanks containing solidified methacrylic acid must not be reheated during transportation. | Browse TP18 |
| TP19 | The calculated wall thickness must be increased by 3 mm at the time of construction. Wall thickness must be verified ultrasonically at intervals midway between periodic hydraulic tests (every 2.5 years). The portable tank must not be used if the wall thickness is less than that prescribed by the applicable T code in Column (7) of the Table for this material. | Browse TP19 |
| TP20 | This hazardous material must only be transported in insulated tanks under a nitrogen blanket. | Browse TP20 |
| TP21 | The wall thickness must not be less than 8 mm. Portable tanks must be hydraulically tested and internally inspected at intervals not exceeding 2.5 years. | Browse TP21 |
| TP22 | Lubricants for portable tank fittings (for example, gaskets, shut-off valves, flanges) must be oxygen compatible. | Browse TP22 |
| TP24 | The portable tank may be fitted with a device to prevent the build up of excess pressure due to the slow decomposition of the hazardous material being transported. The device must be in the vapor space when the tank is filled under maximum filling conditions. This device must also prevent an unacceptable amount of leakage of liquid in the case of overturning. | Browse TP24 |
| TP25 | Sulphur trioxide 99.95% pure and above may be transported in tanks without an inhibitor provided that it is maintained at a temperature equal to or above 32.5 °C (90.5 °F). | Browse TP25 |
| TP26 | The heating device must be exterior to the shell. For UN 3176, this requirement only applies when the hazardous material reacts dangerously with water. | Browse TP26 |
| TP27 | A portable tank having a minimum test pressure of 4 bar (400 kPa) may be used provided the calculated test pressure is 4 bar or less based on the MAWP of the hazardous material, as defined in §178.275 of this subchapter, where the test pressure is 1.5 times the MAWP. | Browse TP27 |
| TP28 | A portable tank having a minimum test pressure of 2.65 bar (265 kPa) may be used provided the calculated test pressure is 2.65 bar or less based on the MAWP of the hazardous material, as defined in §178.275 of this subchapter, where the test pressure is 1.5 times the MAWP. | Browse TP28 |
| TP29 | A portable tank having a minimum test pressure of 1.5 bar (150.0 kPa) may be used provided the calculated test pressure is 1.5 bar or less based on the MAWP of the hazardous materials, as defined in §178.275 of this subchapter, where the test pressure is 1.5 times the MAWP. | Browse TP29 |