Editorial Note on Part 173
Editorial Note: Nomenclature changes to part 173 appear at 70 FR 56098, Sept. 23, 2005.

§ 173.181 Pyrophoric materials (liquids). When the § 172.101 table specifies that a hazardous material be packaged under this section, only the following non-bulk packagings are authorized: ( a ) *Authorized cylinders.* ( 1 ) A specification steel or nickel cylinder prescribed for any compressed gas, except acetylene, having a minimum design pressure of 1206 kPa (175 psig).
( 2 ) DOT 3AL cylinders constructed of aluminum alloy 6061-T6 with a minimum marked service pressure of 1,800 psig and a maximum water capacity of 49 liters (13 gal) may be used for the transportation of inorganic pyrophoric liquids (UN3194). Any preheating or heating of the DOT 3AL cylinder must be limited to a maximum temperature of 79.4 °C (175 °F).
( 3 ) Cylinders authorized under paragraphs (a)(1) and (a)(2) of this section equipped with valves must be: ( i ) Equipped with steel valve protection caps or collars; or
( ii ) Overpacked in a wooden box (4C1, 4C2, 4D or 4F); fiberboard box (4G), or plastic box (4H1 or 4H2). Cylinders must be secured to prevent shifting in the box and, when offered for transportation or transported, must be so loaded that pressure relief devices remain in the vapor space of the cylinder. (See § 177.838(h) of this subchapter.)
( b ) Steel boxes (4A), aluminum boxes (4B), metal boxes, other than steel or aluminum (4N), wooden boxes (4C1, 4C2, 4D, or 4F) or fiberboard boxes (4G); steel drums (1A1 or 1A2), aluminum drums (1B1 or 1B2), metal drums, other than steel or aluminum (1N1 or 1N2), plywood drums (1D), or fiber drums (1G); or steel jerricans (3A1 or 3A2) or aluminum jerricans (3B1 or 3B2) enclosing not more than four strong, tight metal cans with inner receptacles of glass or metal, not over 1 L (0.3 gallon) capacity each, having positive screwcap closures adequately gasketed or alternative closures physically held in place by a means capable of preventing back-off or loosening of the closure due to conditions normally incident to transportation (*e.g.,* impact, vibration, etc.). Inner packagings must be cushioned on all sides with dry, absorbent, incombustible material in a quantity sufficient to absorb the entire contents.
( c ) Steel drums (1A1 or 1A2), aluminum drums (1B1 or 1B2), metal drums, other than steel or aluminum (1N1 or 1N2) or fiber drums (1G); steel jerricans (3A1 or 3A2) or aluminum jerricans (3B1 or 3B2); or steel boxes (4A), aluminum boxes (4B) or metal boxes, other than steel or aluminum (4N) not exceeding 220 L (58 gallons) capacity each with strong, tight inner metal cans not over 4.0 L (1 gallon) capacity each. The strong, tight metal cans must be closed by positive means, not friction. ( 1 ) Inner packagings must have no opening exceeding 25 mm (1 inch) diameter and must be surrounded with noncombustible cushioning material.
( 2 ) Net quantity of pyrophoric liquids may not exceed two-thirds of the rated capacity of the outer drum. For example, a 220 L (58 gallons) outer drum may contain no more than 147 L (39 gallons) of pyrophoric liquids.
( 3 ) Each layer of inner containers must be separated by a metal plate separator in addition to cushioning material.
( d ) Combination packagings consisting of the following: ( 1 ) *Inner packaging.* A 10 liter or 20 liter UN1A1 drum which has been certified to PG I of subpart M of part 178 of this subchapter. Each inner drum must— ( i ) Have minimum wall thickness of 1.9 mm;
( ii ) Have 4 NPT or VCR openings, each with a diameter of 6.3 mm;
( iii ) Be fabricated from stainless steel; and
( iv ) On the upper head, be fitted with a center opening with a maximum diameter of 68.3 mm and the opening sealed with a threaded closure fabricated from 316 stainless steel. No more than two (2) inner drums may be placed inside the outer drum.
( 2 ) *Outer packaging.* A UN1A2 drum that has been certified to the PG I performance level of subpart M of part 178 of this subchapter and a capacity not to exceed 208 L (55 gal). The drum must have a minimum wall thickness of 1.0 mm and the top head must be closed with a steel closing ring with a minimum thickness of 2.4 mm. No more than two (2) inner drums described in paragraph (d)(1) of this section may be placed inside the outer drum.
[Amdt. 173-224, 55 FR 52643, Dec. 21, 1990, as amended at 56 FR 66270, Dec. 20, 1991; 65 FR 58629, Sept. 29, 2000; 66 FR 45183, 45380, Aug. 28, 2001; 68 FR 24660, May 8, 2003; 68 FR 61941, Oct. 30, 2003; 78 FR 1087, Jan. 7, 2013; 80 FR 1159, Jan. 8, 2015; 81 FR 3674, Jan. 21, 2016; 87 FR 44993, July 26, 2022]