§ 173.158 Nitric acid.

• (a) Nitric acid exceeding 40 percent concentration may not be packaged with any other material.
• (b) Nitric acid in any concentration which does not contain sulfuric acid or hydrochloric acid as impurities, when offered for transportation or transported by rail, highway, or water shall be packaged in specification containers as follows:

- (1) 1A1 stainless steel drums are authorized, subject to the following limitations:

• (i) Stainless steel used in drums must conform to the following thicknesses:

Nominal (marked) capacity (in liters) of 1A1 drum Minimum thickness (in mm) of stainless steel 55 0.9 115 1.2 210 1.5 450 2.0

- (ii) Drums weighing less than 85 percent of their original tare weight may not be used.

- (iii) Type 304 or other grades of equivalent corrosion-resistant steels in the as-welded condition are permissible for nitric acid concentrations up to and including 78 percent.

- (iv) For all concentrations of nitric acid, the following are permissible:

• (A) Type 304 heat-treated (quenched in water at 1040 °C (1900 °F)),
• (B) Stabilized Type 347 in the as-welded condition,
• (C) Stabilized Type 347 stress-relieved (845-900 °C (1550-1650 °F)),
• (D) Stabilized Type 347 heat-treated (quenched in water at 1040 °C (1900 °F)), or
• (E) Other grades of equivalent corrosion resistance.
• (v) All parts of drum exposed to lading must be capable of withstanding the corrosive effect of nitric acid to the extent that 65 percent boiling nitric acid does not penetrate the metal more than 0.0381 mm (0.002 inches) per month. (ASTM A 262 may be used for a suitable corrosion test procedure.)

- (vi) In addition to marking required by § 178.503 of this subchapter, the following marks, in lettering of at least 12.7 mm (0.5 inch) height, must be placed on drums used to transport nitric acid:

• (A) The type of steel used in body and head sheets as identified by American Iron and Steel Institute type number, and, in addition, the letters “HT” following the steel designation on containers subject to stress relieving or heat treatment during manufacture.
• (B) The thickness in mm of metal in thinnest part. When the thickness of metal in the body differs from that in the head, both must be indicated with slanting line between and with the gauge of the body indicated first.
• (C) Original tare weight in kilograms, preceded by the letters “TW.”

An example of the markings required by paragraphs (b)(1)(vi) (A), (B), and (C) of this section is “304HT/1.9/2.7/TW55.”

- (2) 4H1 expanded plastics outer packagings with glass inner receptacles of not greater than 2.5 L (0.66 gallon) capacity each. No more than four 2.5 L (0.66 gallon) inner receptacles may be packed in one outer packaging.

• (c) Nitric acid of 80 percent or greater concentration which does not contain sulfuric acid or hydrochloric acid as impurities, when offered for transportation or transported by rail, highway, or water may be packaged in 1B1 aluminum drums.
• (d) Nitric acid of 90 percent or greater concentration, when offered for transportation or transported by rail, highway, or water may be packaged as follows:

- (1) In 4C1, 4C2, 4D or 4F wooden boxes with inner packagings consisting of glass bottles further individually overpacked in tightly closed metal packagings. Glass bottles must be of 2.5 L (0.66 gallon) or less capacity and cushioned with a non-reactive, absorbent material within the metal packagings.

- (2) In combination packagings with 1A2, 1B2, 1N2, 1D, 1G, 1H2, 3H2, 4A, 4B, 4N or 4G outer packagings with inner glass packagings of 2.5 L (0.66 gallons) or less capacity cushioned with a non-reactive, absorbent material and packed within a tightly closed intermediate packaging of metal or plastic.

• (e) Nitric acid of less than 90 percent concentration, when offered for transportation or transported by rail, highway, or water may be packaged in 4A, 4B, or 4N metal boxes, 4G fiberboard boxes or 4C1, 4C2, 4D or 4F wooden boxes with inside glass packagings of not over 2.5 L (0.66 gallon) capacity each. Beginning September 17, 2018, when placed in wooden or fiberboard outer packagings, glass inner packagings must be packed in tightly-closed, intermediate packagings and cushioned with absorbent material sufficient to absorb the entire contents of the package. The intermediate packaging and absorbent material must be compatible with the nitric acid. See § 173.24(e).
• (f) Nitric acid of 70 percent or less concentration, when offered for transportation or transported by rail, highway, or water, may be packaged as follows:

- (1) In composite packagings 6PA1, 6PA2, 6PB1, 6PB2, 6PC, 6PD1, 6PH1, or 6PH2. 6HH1 and 6HA1 composite packaging with plastic inner receptacles meeting the compatibility requirements § 173.24(e) (e.g., PFA Teflon) are authorized.

- (2) In 4H1 expanded plastic boxes with inner glass packagings of not over 2.5 L (0.66 gallon) each.

- (3) In combination packagings with 1A2, 1B2, 1N2, 1D, 1G, 1H2, 3H2, 4C1, 4C2, 4D, 4F, 4G, 4A, 4B or 4N outer packagings and plastic inner packagings not over 2.5 L (0.66 gallon) capacity further individually overpacked in tightly closed metal packagings.

• (g) Nitric acid of more than 70 percent concentration, when offered for transportation or transported by cargo aircraft only, must be packaged in combination packagings with 1A2, 1B2, 1N2, 1D, 1G, 1H2, 3H2, 4C1, 4C2, 4D, 4F, 4G, 4A, 4B or 4N outer packagings with glass or earthenware inner packagings of not over 1 L (0.3 gallon) or glass ampoules of not over 0.5 L (0.1 gallon).
• (h) Nitric acid of less than 70 percent concentration, when offered for transportation in cargo aircraft only must be packaged in combination packagings with 1A2, 1B2, 1N2, 1D, 1G, 1H2, 3H2, 4C1, 4C2, 4D, 4F, 4G, 4A, 4B or 4N outer packagings with inner packagings of—

- (1) Glass or earthenware not over 2.5 L (0.66 gallon) capacity;

- (2) Plastic not over 2.5 L (0.66 gallon) capacity further individually overpacked in tightly closed metal packagings; or

- (3) Glass ampoule not over 0.5 L (0.1 gallon) capacity.

• (i) Nitric acid solutions of concentrations up to 40%, nitric acid by weight when offered for transportation or transported by rail, highway, or cargo vessel, may be packaged in a UN1H1 non-removable head plastic drum, tested and marked at the PG II performance level for liquids with a specific gravity of at least 1.8, and a hydrostatic test pressure appropriate for the hazardous material.

- (1) Each drum may only be used one time and must be destroyed after emptying.

- (2) Each drum must be permanently and legibly marked “Single Trip Only” and “Must be Destroyed When Empty.”

• (j) Nitric acid solutions, other than red fuming, with more than 70% nitric acid and Nitric acid solutions, other than red fuming, with not more than 70% nitric acid, when offered for transportation or transported by rail, highway, cargo vessel, or cargo-only aircraft may be packaged in a UN 4G outer fiberboard box meeting the Packing Group I or II performance level, as appropriate, subject to the following conditions:

- (1) Inner packaging: A plastic (“fluorinated ethylene-propylene” [FEP] polymers, “perfluoroalkoxy” [PFA] polymers or similar materials) bottle with lined screw closure meeting the compatibility requirements of § 173.24(e) of this section and having a net capacity not greater than 2.5 liters (0.66 gallon) each. For cargo-only aircraft, the inner packaging for PG I material may not exceed 1 L (0.3 gal) capacity. The wall thickness of the bottle must not be less than 0.020”.

- (2) Intermediate packaging: (i) A tightly closed rigid-foam plastic receptacle each containing one inner packaging; or

- (ii) A plastic bag containing one inner packaging and placed inside a heavy-wall polypropylene bag lined with polypropylene absorbent material of sufficient capacity to completely absorb the liquid contents of each inner package. Both bags must be tightly sealed with either plastic tape, a wire tie or a cable tie.

[Amdt. 173-224, 55 FR 52643, Dec. 21, 1990, as amended at 56 FR 66270, Dec. 20, 1991; Amdt. 173-241, 59 FR 67509, Dec. 29, 1994; Amdt. 173-255, 61 FR 50626, Sept. 26, 1996; 68 FR 75744, Dec. 31, 2003; 78 FR 1085, Jan. 7, 2013; 81 FR 3673, Jan. 21, 2016; 81 FR 35541, June 2, 2016; 83 FR 28168, June 18, 2018]