(a) General requirements. A cylinder filled with a non-liquefied compressed gas (except gas in solution) must be offered for transportation in accordance with the requirements of this section and Sec. 173.301. In addition, a DOT specification cylinder must meet the requirements in Secs. 173.301a, 173.302a and 173.305, as applicable. UN pressure receptacles must meet the requirements in Secs. 173.301b and 173.302b, as applicable. Where more than one section applies to a cylinder, the most restrictive requirements must be followed.
(b) Aluminum cylinders in oxygen service. Each aluminum cylinder filled with oxygen must meet all of the following conditions:
(1) Metallic portions of a valve that may come into contact with the oxygen in the cylinder must be constructed of brass or stainless steel.
(2) Except for UN cylinders, each cylinder opening must be configured with straight threads only.
(3) Each UN pressure receptacle must be cleaned in accordance with the requirements of ISO 11621 (IBR, see Sec. 171.7 or this subchapter). Each DOT cylinder must be cleaned in accordance with the requirements of GSA Federal Specification RR-C-901D, paragraphs 3.3.1 and 3.3.2 (IBR, see Sec. 171.7 of this subchapter). Cleaning agents equivalent to those specified in Federal Specification RR-C-901D may be used provided they do not react with oxygen. One cylinder selected at random from a group of 200 or fewer and cleaned at the same time must be tested for oil contamination in accordance with Federal Specification RR-C-901D, paragraph 4.3.2, and meet the specified standard of cleanliness.
(4) The pressure in each cylinder may not exceed 3000 psig at 21 C (70 F).
(c) Notwithstanding the provisions of Sec. 173.24(b)(1) and paragraph (f) of this section, an authorized cylinder containing oxygen continuously fed to tanks containing live fish may be offered for transportation and transported.
(d) Shipment of Division 2.1 materials in aluminum cylinders is authorized for transportation only by motor vehicle, rail car, or cargo-only aircraft.
(e) DOT 3AL cylinders manufactured of 6351-T6 aluminum alloy. Suitable safeguards should be provided to protect personnel and facilities should failure occur while filling cylinders manufactured of aluminum alloy 6351-T6 used in self-contained underwater breathing apparatus (SCUBA), self-contained breathing apparatus (SCBA) or oxygen service. The cylinder filler should allow only those individuals essential to the filling process to be in the vicinity of the cylinder during the filling process.
(f) Compressed oxygen and oxidizing gases by aircraft. A cylinder containing oxygen, compressed; compressed gas, oxidizing, n.o.s.; or nitrogen trifluoride is authorized for transportation by aircraft only when it meets the following requirements:
(1) Only DOT specification 3A, 3AA, 3AL, 3E, 3HT, and 39 cylinders, and UN pressure receptacles ISO 9809-1, ISO 9809-2, ISO 9809-3 and ISO 7866 cylinders are authorized.
(2) Cylinders must be equipped with a pressure relief device in accordance with Sec. 173.301(f) and, for DOT 39 cylinders offered for transportation after October 1, 2008, for the other DOT specification cylinders with the first requalification due after October 1, 2008, or for the UN pressure receptacles prior to initial use:
(i) The rated burst pressure of a rupture disc for DOT 3A, 3AA, 3AL, 3E, and 39 cylinders, and UN pressure receptacles ISO 9809-1, ISO 9809-2, ISO 9809-3 and ISO 7866 cylinders must be 100% of the cylinder minimum test pressure with a tolerance of plus zero to minus 10%; and
(ii) The rated burst pressure of a rupture disc for a DOT 3HT cylinder must be 90% of the cylinder minimum test pressure with a tolerance of plus zero to minus 10%.
(3) The cylinder must be placed in a rigid outer packaging that--
(i) Conforms to the requirements of either part 178, subparts L and M of this subchapter at the Packing Group I or II performance level or the performance criteria in Air Transport Association (ATA) Specification No. 300 for a Category I Shipping Container;
(ii) Is capable of passing, as demonstrated by design testing, the Flame Penetration Resistance Test in appendix E to part 178 of this subchapter; and
(iii) Prior to each shipment, passes a visual inspection that verifies that all features of the packaging are in good condition, including all latches, hinges, seams, and other features, and that the packaging is free from perforations, cracks, dents, or other abrasions that may negatively affect the flame penetration resistance and thermal resistance characteristics of the packaging.
(4) The cylinder and the outer packaging must be capable of passing, as demonstrated by design testing, the Thermal Resistance Test specified in appendix D to part 178 of this subchapter.
(5) The cylinder and the outer packaging must both be marked and labeled in accordance with part 172, subparts D and E of this subchapter. The additional marking ``DOT31FP,'' is allowed to indicate that the cylinder and the outer packaging are capable of passing, as demonstrated by design testing, the Thermal Resistance Test specified in appendix D to part 178 of this subchapter.
(6) A cylinder of compressed oxygen that has been furnished by an aircraft operator to a passenger in accordance with 14 CFR Sec. 121.574, Sec. 125.219, or Sec. 135.91 is excepted from the outer packaging requirements of paragraph (f)(3) of this section. [67 FR 51646, Aug. 8, 2002, as amended at 67 FR 61289, Sept. 30, 2002; 68 FR 75745, Dec. 31, 2003; 71 FR 33883; June 12, 2006; 71 FR 51127, Aug. 29, 2006; 72 FR 55098, Sept. 28, 2007; 76 FR 56317, Sept. 13, 2011; 80 FR 1161, Jan. 8, 2015]
Editorial Note: At 80 FR 1161, Jan. 8, 2015, Sec. 173.302 was amended in part by revising paragraphs (a)(1) and (a)(2). These revisions could not be performed due to inaccurate regulatory instruction. Sec. 173.302a Additional requirements for shipment of nonliquefied(permanent) compressed gases in specification cylinders.
(a) Detailed filling requirements. Nonliquefied compressed gases (except gas in solution) for which filling requirements are not specifically prescribed in Sec. 173.304a must be shipped subject to the requirements in this section and Secs. 173.301, 173.301a, 173.302, and 173.305 in specification cylinders, as follows:
(1) DOT 3, 3A, 3AA, 3AL, 3B, 3E, 4B, 4BA and 4BW cylinders.
(2) DOT 3HT cylinders. These cylinders are authorized for aircraft use only and only for nonflammable gases. They have a maximum service life of 24 years from the date of manufacture. The cylinders must be equipped with frangible disc type pressure relief devices that meet the requirements of Sec. 173.301(f). Each frangible disc must have a rated bursting pressure not exceeding 90 percent of the minimum required test pressure of the cylinder. Discs with fusible metal backing are not permitted. Specification 3HT cylinders may be offered for transportation only when packaged in accordance with Sec. 173.301(a)(9).
(3) DOT 39 DOT 39 cylinders. When the cylinder is filled with a Division 2.1 material, the internal volume of the cylinder may not exceed 1.23 L (75 in\3\) or 50 L (3050 in\3\) for chemical under pressure.
(4) DOT 3AX, 3AAX, and 3T cylinders are authorized for Division 2.1 and 2.2 materials and for carbon monoxide. DOT 3T cylinders are not authorized for hydrogen. When used in methane service, the methane must be a nonliquefied gas with a minimum purity of 98.0 percent methane and commercially free of corroding components.
(5) Aluminum cylinders manufactured in conformance with specifications DOT 39 and 3AL are authorized for oxygen only under the conditions specified in Sec. 173.302(b).
(b) Special filling limits for DOT 3A, 3AX, 3AA, 3AAX, and 3T cylinders. A DOT 3A, 3AX, 3AA, 3AAX, and 3T cylinder may be filled with a compressed gas, other than a liquefied, dissolved, Division 2.1, or Division 2.3 gas, to a pressure 10 percent in excess of its marked service pressure, provided:
(1) The cylinder is equipped with a frangible disc pressure relief device (without fusible metal backing) having a bursting pressure not exceeding the minimum prescribed test pressure.
(2) The cylinder's elastic expansion was determined at the time of the last test or retest by the water jacket method.
(3) Either the average wall stress or the maximum wall stress does not exceed the wall stress limitation shown in the following table: ------------------------------------------------------------------------
Average Maximum
wall wall
Type of steel stress stress
limitation limitation------------------------------------------------------------------------I. Plain carbon steels over 0.35 carbon and 53,000 58,000
medium manganese steels........................II. Steels of analysis and heat treatment 67,000 73,000
specified in spec. 3AA.........................III. Steels of analysis and heat treatment 87,000 94,000
specified in spec. DOT-3T......................IV. Plain carbon steels less than 0.35 carbon 45,000 48,000
made prior to 1920.............................------------------------------------------------------------------------
(i)(A) The average wall stress must be computed from the elastic expansion data using the following formula: S = 1.7EE / KV-0.4P Where: S = wall stress, pounds per square inch;EE = elastic expansion (total less permanent) in cubic centimeters;K = factor x 10 -7 experimentally determined for the
(A) The average wall stress must be computed from the elastic expansion data using the following formula: S = 1.7EE / KV-0.4P Where: S = wall stress, pounds per square inch;EE = elastic expansion (total less permanent) in cubic centimeters;K = factor x 10 -7 experimentally determined for the
particular type of cylinder being tested or derived in
accordance with CGA C-5 (IBR, see Sec. 171.7 of this
subchapter);V = internal volume in cubic centimeter (1 cubic inch = 16.387 cubic
centimeters);P = test pressure, pounds per square inch.
(B) The formula in paragraph (b)(3)(i)(A) of this section is derived from the formula in paragraph (b)(3)(ii) of this section and the following: EE = (PKVD\2\) / (D\2\-d\2\)
(ii) The maximum wall stress must be computed from the formula: S = (P(1.3D\2\ + 0.4d\2\)) / (D\2\-d\2\)Where: S = wall stress, pounds per square inch;P = test pressure, pounds per square inch;D = outside diameter, inches;d = D-2t, where t = minimum wall thickness determined by a suitable
method.
(iii) Compliance with average wall stress limitation may be determined by computing the elastic expansion rejection limit in accordance with CGA C-5, by reference to data tabulated in CGA C-5, or by the manufacturer's marked elastic expansion rejection limit (REE) on the cylinder.
(4) An external and internal visual examination made at the time of test or retest shows the cylinder to be free from excessive corrosion, pitting, or dangerous defects.
(5) A plus sign ( + ) is added following the test date marking on the cylinder to indicate compliance with paragraphs (b) (2), (b)(3), and (b)(4) of this section.
(c) Carbon monoxide. Carbon monoxide must be offered in a DOT 3, 3A, 3AX, 3AA, 3AAX, 3AL, 3E, or 3T cylinder having a minimum service pressure of 1800 psig. The pressure in a steel cylinder may not exceed 1000 psig at 21 C (70 F), except that if the gas is dry and sulfur free, the cylinder may be filled to \5/6\ of the cylinder's service pressure or 2000 psig, whichever is less. A DOT 3AL cylinder may be filled to its marked service pressure. A DOT 3AL cylinder is authorized only when transported by motor vehicle, rail car, or cargo-only aircraft.
(d) Diborane and diborane mixtures. Diborane and diborane mixed with compatible compressed gas must be offered in a DOT 3AL1800 or 3AA1800 cylinder. The maximum filling density of the diborane may not exceed 7 percent. Diborane mixed with compatible compressed gas may not have a pressure exceeding the service pressure of the cylinder if complete decomposition of the diborane occurs. Cylinder valve assemblies must be protected in accordance with Sec. 173.301(h).
(e) Fluorine. Fluorine must be shipped in specification 3A1000, 3AA1000, or 3BN400 cylinders without pressure relief devices and equipped with valve protection cap. The cylinder may not be charged to over 400 psig at 21 C (70 F) and may not contain over 2.7 kg (6 lbs) of gas. [67 FR 51646, Aug. 8, 2002, as amended at 68 FR 75745, Dec. 31, 2003; 70 FR 34075, June 13, 2005; 71 FR 54395, Sept. 14, 2006; 72 FR 4455, Jan. 31, 2007; 72 FR 55098, Sept. 28, 2007; 78 FR 1091, Jan. 7, 2013] Sec. 173.302b Additional requirements for shipment of non-liquefied(permanent) compressed gases in UN pressure receptacles.
(a) General. A cylinder filled with a non-liquefied gas must be offered for transportation in UN pressure receptacles subject to the requirements in this section and Sec. 173.302. In addition, the requirements in Secs. 173.301 and 173.301b must be met.
(b) UN pressure receptacles filling limits. A UN pressure receptacle is authorized for the transportation of non-liquefied compressed gases as specified in this section. Except where filling limits are specifically prescribed in this section, the working pressure of a UN pressure receptacle may not exceed \2/3\ of the test pressure of the receptacle. Alternatively, the filling limits specified for non-liquefied gases in Table 1 of P200 of the UN Recommendations (IBR, see Sec. 171.7 of this subchapter) are authorized. In no case may the internal pressure at 65 C (149 F) exceed the test pressure.
(c) Fluorine, compressed, UN 1045 and Oxygen difluoride, compressed, UN 2190. Fluorine, compressed and Oxygen difluoride, compressed must be packaged in a UN pressure receptacle with a minimum test pressure of 200 bar and a maximum working pressure not to exceed 30 bar. A UN pressure receptacle made of aluminum alloy is not authorized. The maximum quantity of gas authorized in each UN pressure receptacle is 5 kg.
(d) Diborane and diborane mixtures, UN 1911. Diborane and diborane mixtures must be packaged in a UN pressure receptacle with a minimum test pressure of 250 bar and a maximum filling ratio dependent on the test pressure not to exceed 0.07. Filling should be further limited so that if complete decomposition of diborane occurs, the pressure of diborane or diborane mixtures will not exceed the working pressure of the cylinder. The use of UN tubes and MEGCs is not authorized.
(e) Carbon monoxide, compressed UN 1016. Carbon monoxide, compressed is authorized in UN pressure receptacles. The settled pressure in a steel pressure receptacle containing carbon monoxide may not exceed \1/3\ of the pressure receptacle's test pressure at 65 C (149 F) except, if the gas is dry and sulfur-free, the settled pressure may not exceed \l/2\ of the marked test pressure. [71 FR 33883, June 12, 2006] Sec. 173.302c Additional requirements for the shipment of adsorbedgases in UN pressure receptacles.
(a) A cylinder filled with an adsorbed gas must be offered for transportation in UN pressure receptacles subject to the requirements in this section and Sec. 173.302, as well as, Secs. 173.301 and 173.301b.
(b) The pressure of each filled cylinder must be less than 101.3 kPa at 20 C (68 F) and must not exceed 300 kPa at 50 C (122 F).
(c) The minimum test pressure of the cylinder must be 21 bar.
(d) The minimum burst pressure of the cylinder must be 94.5 bar.
(e) The internal pressure at 65 C (149 F) of the filled cylinder must not exceed the test pressure of the cylinder.
(f) The adsorbent material must be compatible with the cylinder and must not form harmful or dangerous compounds with the gas to be adsorbed. The gas in combination with the adsorbent material must not affect or weaken the cylinder or cause a dangerous reaction (e.g., a catalyzing reaction).
(g) The quality of the adsorbent material must be verified at the time of each fill to assure the pressure and chemical stability requirements of this section are met each time an adsorbed gas package is offered for transport.
(h) The adsorbent material must not meet the definition of any other hazard class.
(i) Cylinders and closures containing toxic gases with an LC50 less than or equal to 200 ml/m3 (ppm) (see the following Adsorbed Gases Table) must meet the following requirements:
(1) Valve outlets must be fitted with pressure retaining gas-tight plugs or caps having threads matching those of the valve outlets.
(2) Each valve must either be of the packless type with non-perforated diaphragm, or be of a type which prevents leakage through or past the packing.
(3) Each cylinder and closure must be tested for leakage after filling.
(4) Each valve must be capable of withstanding the test pressure of the cylinder and be directly connected to the cylinder by either a taper-thread or other means which meets the requirements of ISO 10692-2 (IBR, see Sec. 171.7 of this subchapter); and
(5) Cylinders and valves must not be fitted with a pressure relief device.
(j) Valve outlets for cylinders containing pyrophoric gases must be fitted with gas-tight plugs or caps having threads matching those of the valve outlets.
(k) The filling procedure must be in accordance with Annex A of ISO 11513 (IBR, see Sec. 171.7 of this subchapter).
(l) The maximum period for periodic requalification must be in accordance with Sec. 180.207(c) of this subchapter.
Adsorbed Gases Table------------------------------------------------------------------------
ID No. Hazardous material LC50 ml/m\3\ Notes------------------------------------------------------------------------3510...... Adsorbed gas, .............. z.
flammable, n.o.s..3511...... Adsorbed gas, n.o.s.... .............. z.3512...... Adsorbed gas, toxic, <=5000 z.
n.o.s..3513...... Adsorbed gas, .............. z.
oxidizing, n.o.s..3514...... Adsorbed gas, toxic, <=5000 z.
flammable, n.o.s..3515...... Adsorbed gas, toxic, <=5000 z.
oxidizing, n.o.s..3516...... Adsorbed gas, toxic, <=5000 z.
corrosive, n.o.s..3517...... Adsorbed gas, toxic, <=5000 z.
flammable, corrosive,
n.o.s..3518...... Adsorbed gas, toxic, <=5000 z.
oxidizing, corrosive,
n.o.s..3519...... Boron trifluoride, 387 a.
adsorbed.3520...... Chlorine, adsorbed..... 293 a.3521...... Silicon tetrafluoride, 450 a.
adsorbed.3522...... Arsine, adsorbed....... 20 d.3523...... Germane, adsorbed...... 620 d, r.3524...... Phosphorus 190
pentafluoride,
adsorbed.3525...... Phosphine, adsorbed.... 20 d.3526...... Hydrogen selenide, 2
adsorbed.------------------------------------------------------------------------Notes:a: Aluminum alloy cylinders must not be used.d: When steel cylinders are used, only those bearing the ``H'' mark in
accordance with Sec. 173.302b(f) are authorized.r: The filling of this gas must be limited such that, if complete
decomposition occurs, the pressure does not exceed two thirds of the
test pressure of the cylinder.z: The construction materials of the cylinders and their accessories
must be compatible with the contents and must not react to form
harmful or dangerous compounds therewith. [80 FR 1161, Jan. 8, 2015]