CFR > Title 49 - Transportation > SUBTITLE B—Other Regulations Relating to Transportation > CHAPTER I—PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (Parts 105–199) > SUBCHAPTER C—HAZARDOUS MATERIALS REGULATIONS (Parts 171–181) > PART 173—SHIPPERS—GENERAL REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS > SUBPART D—Definitions Classification, Packing Group Assignments and Exceptions for Hazardous Materials Other Than Class 1 and Class 7 (§173.115 to §173.156) > 173.121—Class 3—Assignment of packing group.

173.121—Class 3—Assignment of packing group.

(a) The packing group of a Class 3 material is as assigned in column 5 of the § 172.101 table. When the § 172.101 table provides more than one packing group for a hazardous material, the packing group shall be determined by applying the following criteria:
Packing group Flash point (closed-cup) Initial boiling point
I ≤35°C (95 °F)
II <23°C (73 °F) >35 °C (95 °F)
III ≥23 °C, ≤60 °C (≥73 °F, ≤140 °F) >35 °C (95 °F)
(b) Criteria for inclusion of viscous Class 3 materials in Packing Group III. (1) Viscous Class 3 materials in Packing Group II with a flash point of less than 23 °C (73 °F) may be grouped in Packing Group III provided that—
(i) Less than 3 percent of the clear solvent layer separates in the solvent separation test;
(ii) The mixture does not contain any substances with a primary or a subsidiary risk of Division 6.1 or Class 8;
(iii) The capacity of the packaging is not more than 30 L (7.9 gallons); and
(iv) The viscosity and flash point are in accordance with the following table:
Flow time t in seconds Jet diameter in mm Flash point c.c.
20<t≤60 4 above 17 °C (62.6 °F).
60<t≤100 4 above 10 °C (50 °F).
20<t≤32 6 above 5 °C (41 °F).
32<t≤44 6 above −1 °C (31.2 °F).
44<t≤100 6 above −5 °C (23 °F).
100<t 6 −5 °C (23 °F) and below.
(2) The methods by which the tests referred to in paragraph (b)(1) of this section shall be performed are as follows:
(i) Viscosity test. The flow time in seconds is determined at 23 °C (73.4 °F) using the ISO standard cup with a 4 mm (0.16 inch) jet as set forth in ISO 2431 (IBR, see § 171.7 of this subchapter). Where the flow time exceeds 100 seconds, a further test is carried out using the ISO standard cup with a 6 mm (0.24 inch) jet.
(ii) Solvent Separation Test. This test is carried out at 23 °C (73 °F) using a 100.0 mL(3 ounces) measuring cylinder of the stoppered type of approximately 25.0 cm (9.8 inches) total height and of a uniform internal diameter of approximately 30 mm (1.2 inches) over the calibrated section. The sample should be stirred to obtain a uniform consistency, and poured in up to the 100 mL (3 ounces) mark. The stopper should be inserted and the cylinder left standing undisturbed for 24 hours. After 24 hours, the height of the upper separated layer should be measured and the percentage of this layer as compared with the total height of the sample calculated.
[Amdt. 173-224, 55 FR 52634, Dec. 21, 1990, as amended at 56 FR 66268, Dec. 20, 1991; Amdt. 173-241, 59 FR 67507, Dec. 29, 1994 Amdt. 173-255, 61 FR 50625, Sept. 26, 1996; 64 FR 10777, Mar. 5, 1999; 64 FR 51918, Sept. 27, 1999; 66 FR 45381, Aug. 28, 2001; 68 FR 75744, Dec. 31, 2003; 71 FR 78631, Dec. 29, 2006]