DOT Cylinder Maintenance, Retest and Certification Requirements
Visual Inspection and Hydrostatic Testing of Cylinders
173.34 [ General Requirements] [Inspection Table] [Retester authorization]
[Visual inspection] [Pressure Retest] [Cylinder rejection] [Cylinder Condemnation] [Retester Markings] [Recordkeeping] [DOT 4 Series] [ Less 12# - Less 300psi]
[Modified retest] [Modified Conditions] [Exceptions to Hydrostatic - Exclusive U]
[Table of Exclusive U] [Ammonia Exceptions] [3HT Exceptions] [DOT 3A & 3AA] [Corrosives] [DOT 8 and 8AL] [Fire Exstinguishers] [173.301 General Requirements for Shipment of Compresd Gas] [173.40] [Hydrotest Facility]
Qualification, maintenance and u of cylinders.
(a) General qualification for u of cylinders. (See §§173.1 through 173.30 for requirements applying to all shipments.)
(1) No person may charge or fill a cylinder unless it is as specified in this part and part 178 of this subchapter. A cylinder that leaks, is bulged, has defective valves or safety devices, bears evidence of physical abu, fire or heat damage, or detrimental rusting or corrosion, must not be ud unless it is properly repaired and requalified as prescribed in the regulations.
教育培训计划(2) When cylinders with a marked pressure limit are prescribed, other cylinders made under the same specification but with a higher marked rvice pressure limit are authorized. For example, cylinders marked DOT-4B500 may be ud where DOT-4B300 is specified.
(b) Grandfather clau. A cylinder in domestic u previous to the date upon which the specification therefor was first made effective in the regulations may be ud if the cylinder has been properly tested and otherwi complies with the requirements applicable for the gas with which it is charged.
(c) Cylinder marking. Each required marking on a cylinder must be maintained so that it is legible. Retest markings and original markings which are becoming illegible may be reproduced by stamping on a metal plate which must be permanently cured to the cylinder.
(1) Additional information not affecting the markings prescribed in the applicable cylinder specification may be placed on the cylinder. No indentation may be made in the sidewall of the cylind
er unless specifically permitted in the applicable specification.
(2) When the space originally provided for dates of subquent retests becomes filled, the stamping of additional test dates into the external surface of the footring of a cylinder is authorized.
(3) Except for marked rvice pressure, markings required on cylinders may not be altered or removed. The marked rvice pressure may be changed only upon application to the Associate Administrator for Hazardous Materials Safety and receipt of written instructions as to the procedure to be followed. A rvice pressure change is not authorized for a cylinder which fails to pass the prescribed periodic hydrostatic retest, unless it is reheat treated and requalified in accordance
with this ction.
(d) Pressure relief device systems. No person may offer a cylinder charged with a compresd gas for transportation in commerce unless the cylinder is equipped with one or more pressure relief devices sized and lected as to type, location, and quantity and tested in accordance with CGA Pamphlet S-1.1 (compliance with paragraph 9.1.1.1 of CGA Pamphlet S-1.1 is not required). The pressure relief device system must be capable of preventing rupture of the normally charged
cylinder when subjected to a fire test conducted in accordance with CGA Pamphlet C-14, or in the
ca of an acetylene cylinder, CGA Pamphlet C-12. Cylinders shall not be shipped with leaking
safety relief devices. Safety relief devices must be tested for leaks before the charged cylinder is
shipped from the cylinder filling plant; it is expressly forbidden to repair leaking fu plug devices, where leak is through the fusible metal or between the fusible metal and the opening in the plug
body, (except by removal of the device and replacement of the fusible metal.) Exceptions are as
follows:
(1) Except as provided in paragraphs (d)(1) (i) through (iii) of this ction, a pressure relief device is
not required on a cylinder 12 inches or less in length, exclusive of neck, and 4\1/2\ inches or less in
outside diameter.
(i) A pressure relief device is required on a specification 9, 39 (§178.65 of this
subchapter), 40, or 41 cylinder. A metal pressure relief valve is required on a
specification 39 cylinder ud for a liquefied flammable gas. A fusible pressure relief
device is not authorized on a specification 39 cylinder containing a liquefied compresd
gas.
(ii) A pressure relief device is required on a cylinder charged with a liquefied gas for
which this part requires a rvice pressure of 1800 psi or higher.
(iii) A pressure relief device is required on a cylinder charged with a nonliquefied gas to
a pressure of 1,800 psi or higher at 70 °F.
(2) Except for a specification 39 cylinder and a cylinder ud for acetylene in solution, a pressure relief device is not required on a cylinder charged with a nonliquefied gas under pressure of 300 psi or less at 70 °F.
(3) A pressure relief device is prohibited on a cylinder charged with a Division 2.3 or Division 6.1 material in Hazard Zone A.
(4) A pressure relief device is prohibited on a cylinder charged with fluorine.
(5) A pressure relief device is not required on a cylinder charged with methyl mercaptan; with mono-, di-, or trimethylamine, anhydrous; with not over 10 pounds of nitrosyl chloride; or with less than 165 pounds of anhydrous ammonia.
(6) Pressure relief devices, if ud, must be in the vapor space of cylinders containing pyroforic liquids, inorganic or organic, n.o.s., covered by §173.124.
(e) Periodic qualification and marking of cylinders. Each cylinder that becomes due for periodic retest as specified in the following table must be retested and marked in conformance with the requirements of this paragraph (e):
Retest and Inspection of Cylinders Table
DOT Specification 2Minimum retest pressure (p.s.i.) 3Retest period (years)
lol壁纸DOT-33,000 p.s.i.5
DOT-3A, 3AA 5/3 times rvice pressure, except non-corrosive
rvice (173.34(e)(13)
5, 10, or 12 (173.34 (e)(14)
(12)(16) and (19)
DOT-3AX, 3AAX5/3 times rvice pressure5 3B, 3BN 2 times rvice pressure 5 or 10 (e (e)(12)) 3C Retest not required-
3D5/3 times rvice pressure5
1 Any cylinder not exceeding two inches outside diameter and less than two feet in length is excepted from hydrostatic retest.
2 A cylinder in chlorine or sulfur dioxide rvice made before April 20, 1915, must be retested at 500 psi.
3 For cylinders not marked with a rvice pressure, e 173.301(e)(1).
(1) General requirements.
(i) Each cylinder bearing a DOT specification marking (including a cylinder remarked in conformance
with §173.23) must be inspected, retested and marked in conformance with this ction, at the frequency specified in the Retest and Inspection of Cylinders
Table in this paragraph (e). Each cylinder bearing a DOT exemption number must be
inspected, retested and marked in conformance with this ction and the terms of the
applicable exemption, at the frequency specified in the exemption.
(ii) No cylinder required to be retested by paragraph (e)(1)(i) of this ction may be
charged or filled with a hazardous material and transported in commerce unless that cylinder has been inspected and retested in accordance with this ction and the retester
has marked the cylinder by stamping the date of retest, the cylinder retester
identification number unless excepted under this ction, and any other marking
水果泡酒required by this ction. No person may mark a test date or a retester identification number on a DOT specification or exemption cylinder unless all applicable
requirements of this ction have been met.
(2) Retester authorization .
(i) No person may mark a cylinder with a test date or retester identification number,or
otherwi reprent that a DOT specification or exemption cylinder has been retested under this ction, unless that person holds a current retester identification number
issued by the Associate Administrator for Hazardous Material Safety and operates in
compliance with the terms of the retester identification number 3E Retest not required -3HT
5/3 times rvice pressure 3 (e (e)(15)3T
5/3 times rvice pressure 54
700 p.s.i.104A
5/3 times rvice pressure 5 or 10 (e (e)(12)4AA480
2 times rvice pressure 5 or 10 (e)(14)4B, 4BA, 4BW, 4B-240ET两字网名
2 times rvice pressure, except for non-corrossive rvice (173.34(e)(13))5, 10, or 12 (173.34 (e)(12) and (19))4C
Retest not required -4D, 4DA, 4DS
2 times rvice pressure 5DOT-4E
2 times rvice pressure, except for non-corrossive rvice (173.34(e)(13))54L
Retest not required -8, 8AL
10 or 20 (173.34 (e)(18))DOT-9
400 p.s.i. (max. 600 p.s.i.)525
500 p.s.i.526 FILLING OVER 450 psi
5/3 times rvice pressure 526 FILLING AT 450 psi or
less
2 times rvice pressure, except for non-corrossive rvice (173.34(e)(13) 5 or 10 (173.34(e)(11))33
800 p.s.i.538500 p.s.i.5
issuance letter. With the exception of visual inspections, all functions under this ction
羊水少怎么办must be performed or supervid by an individual named as qualified in
the retester identification number application or a notification pursuant to paragraph (e)
(2)(iv) of this ction. A person is not required to obtain a retester identification number,
if the person only performs visual inspections on DOT specification or exemption
cylinders.
(ii) Any person eking approval as a cylinder retester shall arrange for an independent
inspection agency, approved by the Associate Administrator for
Hazardous Material Safety pursuant to §173.300a, to inspect its retest facility. The
person eking approval shall bear the cost of the inspection. Independent inspection
agencies are not RSPA agents or reprentatives. A list of approved independent
inspection agencies is available from the Associate Administrator for Hazardous
Materials Safety, Office of Hazardous Materials Exemptions and Approvals (DHM-32),
Rearch and Special Programs Administration, U.S. Department of Transportation,
Washington, DC 20590-0001. Assistance in obtaining an approval may be requested
from the same address.
(A) After the inspection, the person eking approval must submit a letter of recommendation and inspection report from the independent inspection agency and a completed request for approval to the Associate Administrator for Hazardous Materials Safety at the address listed in this paragraph (e) (2)(ii). An applicant must include the following information: company name; facility location; mailing address (if different from location of facility); business telephone number; name of facility manager; the DOT specification/exemption cylinders that will be tested at the facility; a certification that the facility will operate in compliance with the applicable requirements of this subchapter, the date and an authorized signature.
(B) The Associate Administrator for Hazardous Materials Safety reviews the application, the name, address, ownership, testing equipment, or management or personnel performing any function under this ction, to the Associate Administrator for Hazardous Materials Safety (DHM-32) within 20 days of the change. A retester identification number remains valid only if the retester's facility and qualifications are maintained at or above the level obrved at the time of inspection by the independent inspection agency.
(v) A retester shall maintain, at each location at which it inspects, retests or marks cylinders under this ction:
(A) Current copies of tho portions of this subchapter that apply to its cylinder inspection, retesting and marking activities at that location.
(B) Current copies of all exemptions governing exemption cylinders inspected, retested or marked by the retester at that location.
(C) Copies of each CGA pamphlet incorporated by reference in §171.7 of this subchapter that applies to the retester's cylinder inspection, retesting and marking activities at that location. The publication maintained must be the edition incorporated by reference in §171.7 of this subchapter.
理财书籍(3) Visual inspection.
Except as otherwi provided in this ction, each time a cylinder is retested, it must be visually inspected, internally and externally, in accordance with CGA Pamphlets C-6, C-6.1, C-6.2, or C-6.3, as applicable. The cylinder must be approved, rejected or condemned according to the criteria in the applicable CGA pamphlet. Internal inspection may be omitted for cylinders of the type and in the rvice described under paragraph (e)(13) of this ction. DOT 3BN cylinders must be inspected in
accordance with CGA Pamphlet C-6.
(4) Pressure retest.
(i) Unless otherwi provided, each cylinder required to be retested under this ction
must be retested by means suitable for measuring the expansion of the cylinder under
pressure. Bands and other removable attachments must be looned or removed before
testing so that the cylinder is free to expand in all directions.
(ii) The pressure-indicating device of the testing apparatus must permit reading of
pressures to within 1% of the minimum prescribed test pressure of each cylinder
tested, except that for an analog device, interpolation to \1/2\ of the marked gaugesubmitted
divisions is acceptable. The expansion-indicating device of the testing apparatus
must also permit incremental reading of the cylinder expansion to 1% of the total
expansion of each cylinder tested or 0.1 cubic centimeter, whichever is larger.
Midpoint visual interpolation is permitted.
(iii) Each day before retesting, the retester shall confirm, by using a calibrated
cylinder or other method authorized in writing by the Associate Administrator for
Hazardous Materials Safety that:安全协议书范本
(A) The pressure-indicating device, as part of the retest apparatus, is accurate within ±1.0% of the prescribed test pressure of any cylinder tested that day. The pressure indicating device, itlf, must be certified as having an accuracy of ±0.5%, or better, of its full range, and must permit readings of p
ressure from 90%-110% of the minimum prescribed test pressure of the cylinder to be tested.
The accuracy of the pressure indicating device within the test system can be demonstrated at any point within 500 psi of the actual test pressure for test pressures at or above 3000 psi, or 10% of the actual test pressure for test pressures below 3000 psi; and
(B) The expansion-indicating device, as part of the retest apparatus, gives a stable reading of expansion and is accurate to ±1.0% of the total expansion of any cylinder tested or 0.1 cubic centimeter, whichever is larger. The expansion-indicating device itlf must have an accuracy of
±0.5%, or better, of its full scale.
(iv) The test equipment must be verified to be accurate within ±1.0% of the calibrated cylinder's pressure and corresponding expansion values. This may be accomplished by bringing the pressure to a value shown on the calibration certificate for the calibrated cylinder ud and verifying that the resulting total expansion is within ±1.0% of the total expansion shown on the calibration certificate. Alternatively, calibration may be demonstrated by bringing the total expansion to a known value on the calibration certificate for the calibrated cylinder ud and verifying that the resulting pressure is within ±1.0% of the pressure shown on the calibration certificate. The calibrated cylinder must show
no permanent expansion. The retester shall demonstrate calibration in conformance with this paragraph (e)(4) to an authorized inspector on any day that it retests cylinders.
A retester shall maintain calibrated cylinder certificates in conformance with paragraph (e)(8)(iii) of this ction.
(v) Minimum test pressure must be maintained for at least 30 conds, and as long as necessary for complete expansion of the cylinder. A system check may be performed at or below 90% of test pressure prior to the retest. In the ca of a malfunction of the test equipment, the test may be repeated at a pressure incread by 10 percent or 100 psi, whichever is less. This paragraph (e)(4) does not authorize retest of a cylinder otherwi required to be condemned under paragraph (e)(6) of this ction.
(5) Cylinder rejection.
