[Code of Federal Regulations]
[Title 49, Volume 2, Parts 100 to 185]
[Revised as of October 1, 1998]
From the U.S. Government Printing Office via GPO Access
[CITE: 49CFR173.34]
[Page 387-399]
TITLE 49--TRANSPORTATION
CHAPTER I--RESEARCH AND SPECIAL PROGRAMS ADMINISTRATION, DEPARTMENT OF
TRANSPORTATION
PART 173--SHIPPERS--GENERAL REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS
--Table of Contents
Subpart B--Preparation of Hazardous Materials for Transportation
Sec. 173.34 Qualification, maintenance and use of cylinders.
(a) General qualification for use of cylinders. (See Secs. 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 abuse, fire or heat damage, or detrimental rusting or
corrosion, must not be used unless it is properly repaired and
requalified as prescribed in these regulations.
(2) When cylinders with a marked pressure limit are prescribed,
other cylinders made under the same specification but with a higher
marked service pressure limit are authorized. For example, cylinders
marked DOT-4B500 may be used where DOT-4B300 is specified.
(b) Grandfather clause. A cylinder in domestic use previous to the
date upon which the specification therefor was first made effective in
these regulations may be used if the cylinder has been properly tested
and otherwise 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 secured 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 cylinder unless
specifically permitted in the applicable specification.
(2) When the space originally provided for dates of subsequent
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 service pressure, markings required on
cylinders may not be altered or removed. The marked service 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 service 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 section.
(d) Pressure relief device systems. No person may offer a cylinder
charged with a compressed gas for transportation in commerce unless the
cylinder is equipped with one or more pressure relief devices sized and
selected as to type, location, and quantity and tested in accordance
with CGA Pamphlet S-1.1 (compliance with paragraph 9.1.1.1
[[Page 388]]
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 case 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 fuse 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 section, 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
(Sec. 178.65 of this subchapter), 40, or 41 cylinder. A metal pressure
relief valve is required on a specification 39 cylinder used for a
liquefied flammable gas. A fusible pressure relief device is not
authorized on a specification 39 cylinder containing a liquefied
compressed gas.
(ii) A pressure relief device is required on a cylinder charged with
a liquefied gas for which this part requires a service 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
deg.F.
(2) Except for a specification 39 cylinder and a cylinder used 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 deg.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 used, must be in the vapor space of
cylinders containing pyroforic liquids, inorganic or organic, n.o.s.,
covered by Sec. 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 \1\
------------------------------------------------------------------------
Minimum retest
Specification under which pressure (p.s.i.) Retest period
cylinder was made \2\ \3\ (years)
------------------------------------------------------------------------
DOT-3.......................... 3,000 p.s.i...... 5
DOT-3A, 3AA.................... 5/3 times service 5, 10, or 12 (see
pressure, except Sec. 173.34
non-corrosive (e)(14), (e)(12),
service (see (e)(16), and
Sec. 173.34(e)( (e)(19))
13)).
DOT-3AL........................ 5/3 times service 5 or 12 (see
pressure. (e)(19))
DOT-3AX, 3AAX.................. 5/3 times service 5
pressure.
3B, 3BN........................ 2 times service 5 or 10 (see Sec.
pressure (see 173.34(e)(12))
Sec. 173.34(e)(
13)).
3C............................. Retest not ....................
required.
3D............................. 5/3 times service 5
pressure.
3E............................. Retest not ....................
required.
3HT............................ 5/3 times service 3 (see Sec.
pressure. 173.34(e)(15))
3T............................. 5/3 times service 5
pressure.
4.............................. 700 p.s.i........ 10
4A............................. 5/3 times service 5 or 10 (see Sec.
pressure (see 173.34(e)(12))
Sec. 173.34(e)(
13)).
4AA480......................... 2 times service 5 or 10 (see Sec.
pressure (see 173.34(e)(14))
Sec. 173.34(e)(
13)).
[[Page 389]]
4B, 4BA, 4BW, 4B-240ET......... 2 times service 5, 10 or 12 (see
pressure, except Sec. 173.34
non-corrosive (e)(11), (e)(12)
service (see and (e)(19))
Sec. 173.34(e)(
13)).
4C............................. Retest not ....................
required.
4D, 4DA, 4DS................... 2 times service 5
pressure.
DOT-4E......................... 2 times service 5
pressure, except
non-corrosive
service (see
Sec. 173.34(e)(
13)).
4L............................. Retest not ....................
required.
8, 8AL......................... ................. 10 or 20 (see Sec.
173.34(e)(18))
DOT-9.......................... 400 p.s.i. 5
(maximum 600
p.s.i.).
25............................. 500 p.s.i........ 5
26 for filling at over 450 5/3 times service 5
p.s.i. pressure.
26 for filling at 450 p.s.i. 2 times service 5 or 10 (see Sec.
and below. pressure, except 173.34(e)(11))
non-corrosive
service (see
Sec. 173.34(e)(
13)).
33............................. 800 p.s.i........ 5
38............................. 500 p.s.i........ 5
Special Permit cylinder............. See current See current
special permit. special permit
Foreign cylinder (see Sec. As marked on the 5
173.301(j) for restrictions on cylinder, but
use). not less than 5/
3 of any service
or working
pressure marking.
------------------------------------------------------------------------
\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 service made before April
20, 1915, must be retested at 500 psi.
\3\ For cylinders not marked with a service pressure, see Sec.
173.301(e)(1).
(1) General requirements. (i) Each cylinder bearing a DOT
specification marking (including a cylinder remarked in conformance with
Sec. 173.23) must be inspected, retested and marked in conformance with
this section, at the frequency specified in the Retest and Inspection of
Cylinders Table in this paragraph (e). Each cylinder bearing a DOT
special permit number must be inspected, retested and marked in conformance
with this section and the terms of the applicable special permit, at the
frequency specified in the special permit.
(ii) No cylinder required to be retested by paragraph (e)(1)(i) of
this section 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 section and the retester has marked the
cylinder by stamping the date of retest, the cylinder retester
identification number unless excepted under this section, and any other
marking required by this section. No person may mark a test date or a
retester identification number on a DOT specification or special permit
cylinder unless all applicable requirements of this section have been
met.
(2) Retester authorization. (i) No person may mark a cylinder with a
test date or retester identification number, or otherwise represent that
a DOT specification or special permit cylinder has been retested under this
section, 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 issuance letter. With the exception of visual
inspections, all functions under this section must be performed or
supervised by an individual named as qualified in the retester
identification number application or a notification pursuant to
paragraph (e)(2)(iv) of this section. A person is not required to obtain
a retester identification number, if the person only performs visual
inspections on DOT specification or special permit cylinders.
(ii) Any person seeking approval as a cylinder retester shall
arrange for an independent inspection agency, approved by the Associate
Administrator for Hazardous Material Safety pursuant to Sec. 173.300a,
to inspect its retest facility. The person seeking approval shall bear
the cost of the inspection. Independent inspection agencies are
[[Page 390]]
not PHMSA agents or representatives. A list of approved independent
inspection agencies is available from the Associate Administrator for
Hazardous Materials Safety, Office of Hazardous Materials Special Permits and
Approvals (PHH-32), Research 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 seeking 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/special permit 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 inspection report and recommendation
submitted by the independent inspection agency, and other available
information. The Associate Administrator for Hazardous Materials Safety
issues a retester identification number upon a finding that the
applicant's facility and qualifications are adequate to properly
inspect, test and mark cylinders under this section. Unless otherwise
provided in the retester identification number issuance letter, a
retester identification number expires five years from the date of
issuance.
(iii) An approved retester shall apply for retester identification
number renewal in a timely manner. A new inspection report and
recommendation of an independent inspection agency are required for each
renewal. If the Associate Administrator for Hazardous Materials Safety
receives a renewal application with the accompanying inspection report
and recommendation at least 50 days before expiration of the retester
identification number, the retester identification number remains in
effect until the Associate Administrator for Hazardous Materials Safety
issues a renewal or notifies the retester that its request for renewal
of the retester identification number is denied. The Associate
Administrator for Hazardous Materials Safety considers renewal of a
retester identification number in accordance with the standard in
paragraph (e)(2)(ii)(B) of this section.
(iv) The retester identification number holder shall report in
writing any change in its name, address, ownership, testing equipment,
or management or personnel performing any function under this section,
to the Associate Administrator for Hazardous Materials Safety (PHH-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 observed 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 section:
(A) Current copies of those portions of this subchapter that apply
to its cylinder inspection, retesting and marking activities at that
location.
(B) Current copies of all special permits governing special permit cylinders
inspected, retested or marked by the retester at that location.
(C) Copies of each CGA pamphlet incorporated by reference in
Sec. 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
Sec. 171.7 of this subchapter.
(3) Visual inspection. Except as otherwise provided in this section,
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
service described under paragraph (e)(13) of this section. DOT
[[Page 391]]
3BN cylinders must be inspected in accordance with CGA Pamphlet C-6.
(4) Pressure retest. (i) Unless otherwise provided, each cylinder
required to be retested under this section must be retested by means
suitable for measuring the expansion of the cylinder under pressure.
Bands and other removable attachments must be loosened 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 gauge 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:
(A) The pressure-indicating device, as part of the retest apparatus,
is accurate within <plus-minus>1.0% of the prescribed test pressure of
any cylinder tested that day. The pressure indicating device, itself,
must be certified as having an accuracy of <plus-minus>0.5%, or better,
of its full range, and must permit readings of pressure 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
<plus-minus>1.0% of the total expansion of any cylinder tested or 0.1
cubic centimeter, whichever is larger. The expansion-indicating device
itself must have an accuracy of <plus-minus>0.5%, or better, of its full
scale.
(iv) The test equipment must be verified to be accurate within
<plus-minus>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
used and verifying that the resulting total expansion is within
<plus-minus>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 used and verifying that the resulting pressure
is within <plus-minus>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 section.
(v) Minimum test pressure must be maintained for at least 30
seconds, 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 case of a malfunction of the test
equipment, the test may be repeated at a pressure increased by 10
percent or 100 psi, whichever is less. This paragraph (e)(4) does not
authorize retest of a cylinder otherwise required to be condemned under
paragraph (e)(6) of this section.
(5) Cylinder rejection. (i) A retester shall reject a cylinder when
on visual inspection, it meets a rejection standard in CGA Pamphlets C-
6, C-6.1, C-6.2, or C-6.3, as applicable.
(ii) Except as provided in paragraph (e)(5)(iv) of this section, a
cylinder that is rejected may not be marked as meeting the requirements
of this section.
(iii) When a cylinder is rejected, the retester shall notify the
cylinder owner, in writing, that the cylinder has been rejected and,
unless requalified as provided in paragraph (e)(5)(iv) of this section,
may not be filled with a hazardous material for transportation in
commerce where use of a specification packaging is required.
[[Page 392]]
(iv) A rejected cylinder with a service pressure of less than 900
psig may be requalified and marked if the cylinder is repaired or
rebuilt and subsequently reinspected and retested in conformance with--
(A) CGA Pamphlets C-6, C-6.1, C-6.2, or C-6.3, as applicable;
(B) Parts 173 and 178 of this subchapter;
(C) Any special permit specific to that cylinder; and
(D) Any approval required under paragraphs (i) and (l) of this
section.
(6) Cylinder condemnation. (i) A cylinder must be condemned when--
(A) On inspection, it meets a condition for condemnation in CGA
Pamphlets C-6, C-6.1, C-6.2, or C-6.3, as applicable;
(B) The cylinder leaks through its wall;
(C) Evidence of cracking exists to the extent that the cylinder is
likely to be weakened appreciably;
(D) For a DOT specification cylinder other than a DOT 4E aluminum
cylinder, permanent expansion exceeds 10 percent of total expansion;
(E) For a DOT 4E aluminum cylinder, permanent expansion exceeds 12
percent of total expansion;
(F) For a DOT special permit cylinder, permanent expansion exceeds the
limit in the applicable special permit, or the cylinder meets another
criterion for condemnation in the applicable special permit; or
(G) For a DOT specification 3HT cylinder, elastic expansion exceeds
the marked rejection elastic expansion.
(ii) When a cylinder is required to be condemned, the retester shall
stamp a series of X's over the DOT specification number and the marked
service pressure or stamp ``CONDEMNED'' on the shoulder, top head, or
neck using a steel stamp. Alternatively, at the direction of the owner,
the retester may render the cylinder incapable of holding pressure.
(iii) When a cylinder is required to be condemned, the retester
shall notify the cylinder owner, in writing, that the cylinder is
condemned and may not be filled with hazardous material for
transportation in commerce where use of a specification packaging is
required.
(iv) A cylinder that is condemned may not be filled with hazardous
material for transportation in commerce where use of a specification
packaging is required and may not be marked as meeting the requirements
of this section or any DOT special permit. No person may remove or obliterate
the ``CONDEMNED'' marking.
(7) Retester markings. (i) Each cylinder passing retest must be
marked with the retester's identification number set in a square
pattern, between the month and year of the retest date, in characters
not less than \1/8\-inch high. The first character of the retester
identification number must appear in the upper left corner of the square
pattern; the second in the upper right; the third in the lower right,
and the fourth in the lower left. Example: A cylinder retested in May
1994, and approved by a person who has been issued retester
identification number ``A123'', would be marked plainly and permanently
into the metal of the cylinder in accordance with location requirements
of the cylinder specification or on a metal plate permanently secured to
the cylinder in accordance with paragraph (c) of this section:
[GRAPHIC] [TIFF OMITTED] TR28MY96.000
(ii) Markings of previous tests may not be obliterated. A cylinder
that is subject to the requirements of paragraph (e) (10), (11)
(modified hydrostatic test only), (13) or (14) of this section is not
required to be marked with a retester identification number. A cylinder
requalified by the modified hydrostatic test method or external
inspection must be marked after a retest or an inspection by stamping
the date of retest or reinspection on the cylinder followed by the
symbol ``E'' (external inspection) or ``S'' (modified hydrostatic test
method) as appropriate. However, a cylinder subject to the requirements
of Sec. 173.301(j) may not be marked with a retester identification
number. Variation from the marking requirement may be approved on
written request to the Associate Administrator for Hazardous Materials
Safety.
[[Page 393]]
(8) Recordkeeping. A retester shall maintain the following records
at the retesting location, on paper or in a form from which a paper copy
can be produced on request.
(i) Records of authority to inspect, retest and mark must be
maintained, as follows:
(A) Current retester identification number issuance letter;
(B) If the retester identification number has expired and renewal is
pending, a copy of the renewal request; and
(C) Copies of notifications to Associate Administrator for Hazardous
Materials Safety required under paragraph (e)(2)(iv) of this section.
(ii) Daily records of visual inspection and hydrostatic retest must
be maintained until either the expiration of the retest period or until
the cylinder is again reinspected or retested, whichever occurs first. A
single date may be used for each retest sheet, provided each retest on
the sheet was conducted on that date. Ditto marks or a solid vertical
line may be used to indicate repetition of the preceding entry for the
following entries: date; actual dimensions or a symbol; if present,
manufacturer's name or symbol; if present, owner's name or symbol and
retest operator. Blank spaces may not be used to indicate repetition of
a prior entry. Records must include--
(A) For each test to demonstrate calibration, the date; serial
number of the calibrated cylinder; calibration test pressure; total,
elastic and permanent expansions; and legible identification of retest
operator. The retest operator must be able to demonstrate that the
results of the daily calibration verification correspond to the
hydrostatic retests that were performed on that day. The daily
verification of calibration(s) may be recorded on the same sheets as,
and with, retest records for that date;
(B) For each cylinder retested or visually inspected, records
containing the date; serial number; ICC/DOT specification or special permit
number; service pressure; actual dimensions or a symbol; if present,
manufacturer's name or symbol; if present, owner's name or symbol;
result of visual inspection; actual test pressure; total, elastic and
permanent expansions; percent permanent expansion; disposition, with
reason for any repeated retest, rejection or condemnation; and legible
identification of test operator. For each cylinder marked pursuant to
Sec. 173.302(c)(5), the retest sheet must indicate the method by which
any average or maximum wall stress was computed. Records must be kept
for all completed retests, as well as unsuccessful retests under
paragraph (e)(4)(v) of this section. The entry for a later retest under
paragraph (e)(4)(v) of this section after a failure to hold test
pressure, or retest of a cylinder requalified after rejection, must
indicate the date of the earlier inspection or retest; and
(C) Calculations of average and maximum wall stress pursuant to
Sec. 173.302(c)(3), if performed.
(iii) The most recent certificate of calibration must be maintained
for each calibrated cylinder used by the retester.
(9) DOT 4-series cylinders. A DOT 4-series cylinder, except 4L
cylinders, that at any time shows evidence of a leak or of internal or
external corrosion, denting, bulging or rough usage to the extent that
it is likely to be weakened appreciably; or that has lost five percent
or more of its official tare weight must be retested before being
recharged and shipped. (Refer to CGA Pamphlet C-6 or C-6.3, as
applicable, regarding cylinder weakening.) After retest, the actual tare
weight must be recorded as the new tare weight.
(10) Cylinders 12 pounds or less with service pressures of 300 psi
or less. A cylinder of 12 pounds or less water capacity authorized for
service pressure of 300 psi or less must be given a complete external
visual inspection at the time periodic retest becomes due. External
visual inspection must be in accordance with CGA Pamphlet C-6 or C-6.3.
The cylinder may be hydrostatically retested without a water jacket and
without determining total and permanent expansions. The retest is
successful if the cylinder, when examined under test pressure, does not
display a defect described in paragraph (e)(6)(i) (B) or (C) of this
section.
(11) Modified hydrostatic retest. A cylinder made in compliance with
specification DOT 4B, DOT 4BA, DOT 4BW,
[[Page 394]]
DOT 4E or ICC-26-300 <SUP>2</SUP> (Secs. 178.50, 178.51, 178.61, 178.68
of this subchapter) that is used exclusively for anhydrous
dimethylamine; anhydrous methylamine; anhydrous trimethylamine; methyl
chloride; liquefied petroleum gas; methylacetylene-propadiene
stabilized; or dichlorodifluoromethane, difluoroethane,
difluorochloroethane, chlorodifluoromethane, chlorotetrafluoroethane,
trifluorochloroethylene, or mixture thereof, or mixtures of one or more
with trichlorofluoromethane; and that is commercially free from
corroding components and protected externally by a suitable corrosion-
resistant coating (such as galvanizing or painting) may be given a
hydrostatic retest every 12 years instead of every five years.
Alternatively, the cylinder may be subjected to internal hydrostatic
pressure of at least two times the marked service pressure without
determination of expansions, but this latter type of test must be
repeated every seven years after expiration of the first 12-year period.
When subjected to the latter test, the cylinder must be carefully
examined under test pressure and removed from service if a leak or other
harmful defect exists. A cylinder requalified by the modified
hydrostatic test method must be marked after a retest or an inspection
by stamping the date of retest or reinspection on the cylinder followed
by a ``S''.
---------------------------------------------------------------------------
\2\ For filling at 450 p.s.i. and below. Use of existing cylinders
authorized; new construction not authorized.
---------------------------------------------------------------------------
(12) A cylinder made in conformance with specification DOT-3A, DOT-
3AA, DOT-3B, DOT-4BA or DOT-4BW (Secs. 178.36, 178.37, 178.38, 178.51,
178.61 of this subchapter) having a service pressure of 300 psi or less
that is used exclusively for methyl bromide, liquid; mixtures of methyl
bromide and ethylene dibromide, liquid; mixtures of methyl bromide and
chlorpicrin, liquid; mixtures of methyl bromide and petroleum solvents,
liquid; or methyl bromide and nonflammable, nonliquefied compressed gas
mixtures, liquid; that is commercially free of corroding components, and
that is protected externally by a suitable corrosion resistant coating
(such as galvanizing or painting) and internally by a suitable corrosion
resistant lining (such as galvanizing) may be tested every 10 years
instead of every five years, provided that a visual internal and
external examination of the cylinder is conducted every five years in
accordance with CGA Pamphlet C-6. The cylinder must be examined at each
filling, and rejected if a dent, corroded area, leak or other condition
indicates possible weakness.
(13) A cylinder made in conformance with a specification listed in
the table in this paragraph (e)(13) and used exclusively in the service
indicated may, instead of a periodic hydrostatic retest, be given a
complete external visual inspection at the time periodic retest becomes
due. External visual inspection must be in accordance with CGA Pamphlet
C-6 or C-6.3. When this inspection is used instead of hydrostatic
retesting, subsequent inspections are required at five-year intervals
after the first inspection. Inspections must be made only by competent
persons and the results recorded and maintained in accordance with
paragraph (e)(8) of this section. Records shall include: date of
inspection (month and year); DOT specification number; cylinder
identification (registered symbol and serial number, date of
manufacture, and owner); type of cylinder protective coating (including
statement as to need of refinishing or recoating); conditions checked
(e.g., leakage, corrosion, gouges, dents or digs in shell or heads,
broken or damaged footring or protective ring or fire damage);
disposition of cylinder (returned to service, returned to cylinder
manufacturer for repairs or scrapped). A cylinder that passes inspection
shall be marked with the date in accordance with paragraph (e)(7) of
this section. An ``E'' after the date indicates requalification by the
external inspection method. Specification cylinders must be in exclusive
service as follows:
[[Page 395]]
------------------------------------------------------------------------
Cylinders made in compliance with-- Used exclusively for--
------------------------------------------------------------------------
DOT-4, DOT-3A, DOT-3AA, DOT-3A480X, DOT- Anhydrous ammonia of at least
4A, DOT-4AA480.. 99.95% purity.
DOT-3A, DOT-3AA, DOT-3A480X, DOT-3B, Butadiene, inhibited, which is
DOT-4B, DOT-4BA, DOT-4BW, ICC-26- commercially free from
240,\1\ ICC-26-300\1\. corroding components.
DOT-3A, DOT-3A480X, DOT-3AA, DOT-3B, Cyclopropane which is
DOT-4A, DOT-4AA480, DOT-4B, DOT-4BA, commercially free from
DOT-4BW. corroding components.
DOT-3A, DOT-3AA, DOT-3A480X, DOT-4B, Fluorinated hydrocarbons and
DOT-4BA, DOT-4BW, DOT-4E. mixtures thereof which are
commercially free from
corroding components.
DOT-3A, DOT-3AA, DOT-3A480X, DOT-3B, Liquefied hydrocarbon gas which
DOT-4B, DOT-4BA, DOT-4BW, DOT-4E, ICC- is commercially free from
26-240,1 ICC-26-3001. corroding components.
DOT-3A, DOT-3AA, DOT-3A480X, DOT-3B, Liquefied petroleum gas which
DOT-4B, DOT-4BA, DOT-4BW, DOT-4E, ICC- is commercially free from
26-2401, ICC-26-3001. corroding components.
DOT-3A, DOT-3AA, DOT-3B, DOT-4B, DOT- Methylacetylene-propadiene,
4BA, DOT-4BW, DOT-4E. stabilized, which is
commercially free from
corroding components.
DOT-3A, DOT-3AA, DOT-3B, DOT-4B, DOT- Anhydrous mono, di,
4BA, DOT-4BW. trimethylamines which are
commercially free from
corroding components.
DOT-4B240, DOT-4BW240.................. Ethyleneimine, inhibited.
------------------------------------------------------------------------
\1\ Use of existing cylinders authorized; new construction not
authorized.
(14) Cylinders containing anhydrous ammonia. A cylinder made in
compliance with specification DOT-3A, DOT-3A 480X, or DOT-4AA480 used
exclusively for anhydrous ammonia, commercially free from corroding
components, and protected externally by a suitable corrosion-resistant
coating (such as painting) may be retested every 10 years instead of
every five years.
(15) 3HT cylinders. (i) In addition to the other requirements of
this section, a cylinder marked DOT-3HT must be requalified in
accordance with CGA Pamphlet C-8.
(ii) The cylinder must be condemned:
(A) If elastic expansion exceeds the marked rejection elastic
expansion. A cylinder made before January 17, 1978, and not marked with
a rejection elastic expansion in cubic centimeters near the marked
original elastic expansion must be so marked before the next retest
date. The rejection elastic expansion for a cylinder is 1.05 times its
original elastic expansion.
(B) If there is evidence of denting or bulging.
(C) Twenty-four years after the date of the original test or after
4,380 pressurizations, whichever occurs first. If a cylinder is
recharged, on average, more than once every other day, an accurate
record of the number of rechargings must be maintained by the cylinder
owner or his/her agent.
(iii) The retest date and retester identification number must be
applied by low-stress steel stamp to a depth no greater than that of the
marking at the time of manufacture. Stamping on the sidewall is not
authorized.
(16) DOT-3A or 3AA cylinders. (i) A cylinder made in conformance
with specification DOT-3A or 3AA with a water capacity of 125 pounds or
less that is removed from any cluster, bank, group, rack or vehicle each
time it is filled, may be retested every ten years instead of every five
years, provided the cylinder complies with all of the following--
(A) The cylinder was manufactured after December 31, 1945;
(B) The cylinder is used exclusively for air, argon, cyclopropane,
ethylene, helium, hydrogen, krypton, neon, nitrogen, nitrous oxide,
oxygen, sulfur hexafluoride, xenon, permitted mixtures of these gases
(see Sec. 173.301(a)) and permitted mixtures of these gases with up to
30 percent by volume of carbon dioxide, provided that the gas has a dew
point at or below minus 52 deg.F at 1 atmosphere;
(C) Before each refill, the cylinder passes the hammer test
specified in CGA Pamphlet C-6;
(D) The cylinder is dried immediately after hydrostatic testing to
remove all traces of free water;
(E) The cylinder is not used for underwater breathing; and
(F) Each cylinder is stamped with a five-point star at least one-
fourth of an inch high immediately following the test date.
(ii) If, since the last required hydrostatic retest, a cylinder has
not been used exclusively as specified in paragraph (e)(16)(i)(B) of
this section, but
[[Page 396]]
currently conforms with all other provisions of paragraph (e)(16)(i) of
this section, it may be retested every 10 years instead of every five
years, provided it is first retested and examined as prescribed by
Sec. 173.302(c)(2), (3) and (4).
(iii) Except as specified in paragraph (e)(16)(ii) of this section,
if a cylinder marked with a star is charged with a compressed gas other
than as specified in this paragraph (e)(16), the star following the most
recent test date must be obliterated. The cylinder must be retested five
years from the marked retest date, or prior to the first charging with a
compressed gas, if the required five-year retest period has passed.
(17) Cylinders containing corrosive materials. (i) A cylinder that
previously contained a Class 8 (corrosive) material may not be used to
transport a compressed gas in commerce unless the following requirements
are met--
(A) The cylinder is visually inspected, internally and externally,
in accordance with CGA Pamphlet C-6;
(B) Regardless of the date of previous retest, the cylinder is
subjected to and passes inspection and hydrostatic retest in accordance
with this section; and
(C) The record prescribed in paragraph (e)(8) of this section
includes: the month and year of inspection and test; the cylinder
identification (including ICC or DOT specification number, registered
symbol, serial number, date of manufacture and owner); the conditions
checked (e.g., leakage, corrosion, gouges, dents, or digs in shell or
heads, broken or damaged footrings, fire damage) and the disposition of
the cylinder (returned to service, returned to the manufacturer for
repairs, or scrapped).
(ii) A cylinder requalified for compressed gas service in accordance
with this paragraph (e)(17) may have its next retest and inspection
scheduled from the date of the inspection and retest prescribed in this
paragraph (e). If decontamination cannot remove all significant residue
or impregnation by the Class 8 material, the cylinder may not be used to
transport compressed gas in commerce.
(18) DOT 8 and 8AL cylinders. (i) Each owner of a DOT 8 or 8AL
cylinder used to transport acetylene must have the cylinder shell and
the porous filler requalified in accordance with CGA Pamphlet C-13.
Requalification must be performed in accordance with the following
schedule:
----------------------------------------------------------------------------------------------------------------
Shell (visual inspection) Porous filler requalification
requalification ---------------------------------------
Date of cylinder manufacture ----------------------------------------
Initial Subsequent Initial Subsequent
----------------------------------------------------------------------------------------------------------------
Before January 1, 1991.......... Before January 1, 10 yrs........... Before January 1, Not required.
2001. 2011.
On or after January 1, 1991..... 10 yrs \1\......... 10 yrs........... 3 to 20 yrs \2\.... Not required.
----------------------------------------------------------------------------------------------------------------
\1\ Years from date of cylinder manufacture.
\2\ For a cylinder manufactured on or after January 1, 1991, requalification of the porous filler must be
performed no sooner than 3 years, and no later than 20 years, from the date of manufacture.
(ii) Unless requalified and marked in accordance with CGA Pamphlet
C-13 before October 1, 1994, an acetylene cylinder must be requalified
by a person who holds a valid retester identification number. Each
cylinder successfully passing a shell or filler requalification must be
marked with the retester's identification number in accordance with
paragraph (e)(7) of this section. In addition, the cylinder must be
marked to identify the type of requalification performed in accordance
with paragraph 5.6 of CGA Pamphlet C-13. For example, the letter ``S''
must be used for a shell requalification and the letter ``F'' for a
porous filler requalification.
(iii) If a cylinder valve is replaced, a cylinder valve of the same
weight must be used or the tare weight of the cylinder must be adjusted
to compensate for valve weight differential.
(19) Cylinders used as fire extinguishers. Only DOT specification
cylinders used as fire extinguishers and meeting Special Provision 18 in
Sec. 172.102(c)(1) of this subchapter may be retested in accordance with
this paragraph (e)(19).
(i) A DOT specification 4B, 4BA, 4B240ET or 4BW (Secs. 178.50,
178.51, 178.55
[[Page 397]]
and 178.61 of this subchapter) cylinder may be retested as follows:
(A) For a cylinder with a water capacity of 12 pounds or less by
hydrostatic test using the water jacket method or by hydrostatic test
without determination of expansion (modified hydrostatic test method). A
retest must be performed 12 years after the original test date and at
12-year intervals thereafter.
(B) For a cylinder having a water capacity over 12 pounds--
(1) By hydrostatic test without determination of expansion (modified
hydrostatic test method). A retest must be performed 12 years after the
original test date and at 7-year intervals; or
(2) By hydrostatic test using the water jacket method. A retest must
be performed 12 years after the original test date and at 12-year
intervals thereafter.
(ii) A DOT specification 3A, 3AA, or 3AL (Secs. 178.36, 178.37 and
178.46 of this subchapter) cylinder may be retested by hydrostatic test
using the water jacket method. A retest must be performed 12 years after
the original test date and at 12-year intervals thereafter.
(f) Cylinders subjected to the action of fire. A cylinder which has
been subjected to the action of fire must not again be placed in service
until it has been properly reconditioned as follows:
(1) A cylinder made of plain carbon steel with not over 0.25 percent
carbon nor over 0.90 manganese need not be reheat-treated but must pass
the periodic retest requirements as specified in paragraph (e) of this
section.
(2) DOT 8 and 8AL cylinders made entirely of carbon steel with 0.25
percent or less carbon and with 0.90 percent or less manganese, must be
reinspected to determine the condition of the cylinder and the porous
filler, as prescribed in CGA Pamphlet C-13. If the cylinder has been
damaged, the porous filler must be removed and the cylinder must be heat
treated and retested. The porous filler must be replaced in accordance
with the specification to which the cylinder was made. A cylinder may be
returned to service without reheat treatment or retest if the cylinder
has no fire or mechanical damage and the porous filler is unchanged and
intact.
(3) The inner cylinders made under specification DOT-4L (Sec. 178.57
of this chapter) may be used after again passing the original
hydrostatic test.
(4) DOT 3AL and DOT 4E aluminum cylinders may not be reheat treated
and must be removed from service.
(5) Other cylinders must be reheat treated and reconditioned as
specified in paragraph (g) of this section.
(g) Reheat treatment. (1) Previous to the reheat treatment procedure
hereinafter prescribed, each cylinder must be subjected to a careful
internal and external inspection.
(2) Cylinders must be segregated for reheat treatment in lots of 100
or less cylinders of the same general size having practically the same
chemical composition.
(3) The reheat treatment operation must be carried out, supervised,
and reported as prescribed for the heat treatment in the specification
covering the manufacture of the cylinder in question. Data from the
original reports of manufacture of the cylinders must be available.
(4) The reheat treatment must be followed by hydrostatic retest,
such retest to be carried out, supervised, and reported as prescribed
for the hydrostatic tests in the specification covering the manufacture
of the cylinder in question. The results of the retest must meet either
of the following conditions:
(i) The permanent expansion shall be from zero to 10 percent of the
total expansion in the hydrostatic retest and one cylinder from each lot
shall pass the requirements of the flattening and physical tests
prescribed. Failure to pass the flattening or physical tests will reject
the lot or;
(ii) The permanent expansion shall not be less than 3 percent nor
more than 10 percent of the total expansion in the hydrostatic retest,
in which case the flattening and physical tests are not required. For
this alternative method the hydrostatic retest pressure may not exceed
115 percent of the minimum prescribed test pressure.
(h) Repair by welding or brazing of specifications DOT-3A, 3AA, 3B,
3C cylinders. Repair of specifications DOT-3A, 3AA, 3B or 3C
(Secs. 178.36(e), 178.37(e),
[[Page 398]]
178.38(e), and 178.40(e) of this subchapter) cylinders by welding or
brazing authorized, but only for the removal and replacement of
neckrings and footrings attached to cylinders originally manufactured to
conform to Secs. 178.36-9(a), 178.37-9(a), 178.38-9(a), and 178.40-9(a)
of this subchapter. Removal and replacement must be done by a regular
manufacturer of this type of cylinder. After removal and before
replacement of such parts, cylinders must be inspected, and defective
ones rejected. Cylinders, neckrings, footrings, and method of
replacement must conform to Sec. 178.36(e), 178.37(e), 178.38(e), or
178.40(e) of this subchapter whichever applies. Replacement must be
followed by reheat treating, testing, inspection, and supervised and
reported as prescribed by the specification covering their original
manufacture. Inspector's reports must conform with that required by the
specification covering original manufacture with the word ``repaired''
substituted for ``manufactured.'' Show original markings and the new
additional markings added, and statement: ``Cylinders were carefully
inspected for defects after removal of neckrings and footrings and after
replacement, which replacement was made by process of __________
(Welding-brazing).''
(i) Repair by welding or brazing of DOT-4 series and DOT-8, welded
or brazed cylinders. Repairs on DOT-4 series and DOT-8 series welded or
brazed cylinders are authorized to be made by welding or brazing. Such
repairs must be made by a manufacturer of these types of DOT cylinders
or by a repair facility approved by the Associate Administrator for
Hazardous Materials Safety and by a process similar to that used in its
manufacture and under the following specific requirements:
(1) Cylinders with injurious defects in welded joints in or on
pressure parts must be repaired by completely removing the defect prior
to rewelding.
(2) Cylinders with injurious defects in brazed joints in or on
pressure parts must be repaired by rebrazing.
(3) Cylinders during welding must be free of materials in contact
with the welded joint that may impair the serviceability of the metal in
or adjacent to the weld. (Precautions must be taken to prevent acetylene
cylinder steels from picking up carbon during repair.)
(4) Neckrings, footrings, or other nonpressure attachments
authorized by the specification may be replaced or repaired. Repair or
replacement of footrings, neckrings, or other nonpressure attachments
authorized by the specification for DOT-4BA and 8AL (Secs. 178.51 and
178.60 of this subchapter) cylinders may be made without conforming to
the requirements of paragraph (i)(6) of this section provided the
following requirements are met:
(i) Must be done by a manufacturer of these types of DOT cylinders
or by a repair facility approved by the Associate Administrator for
Hazardous Materials Safety.
(ii) The welder shall have available to him information as to the
procedure equipment, and rod used during manufacture and shall use a
similar method for repair.
(iii) Repairs must be by metal arc welding only. Welds shall be 3
inches maximum length and spaced at least 3 inches apart.
(iv) Welds shall not be made on or near a brazed joint (to prevent
the possibility of copper penetration).
(v) After repair the welds are to be inspected visually for weld
quality.
(vi) After repair the weld area is to be leak tested at the service
pressure of the cylinder.
(5) After removal, and before replacement of attachments, cylinders
must be inspected and defective ones rejected, repaired or rebuilt.
(6) After repair, cylinders must be reheat-treated, tested,
inspected and reported when and as prescribed by the specification
covering their original manufacture when welding or brazing seams in a
pressure part of a cylinder; or when welding or brazing on pressure
parts of cylinders of plain carbon steels with carbon over 0.25 percent
or manganese over 1.00 percent or of alloy steels except as provided in
Sec. 173.34(i)(7).
Note 1: Heat-treatment is not required after welding or brazing
weldable low carbon parts to attachments of similar material which has
been previously welded or brazed to the top or bottom of cylinders and
properly heat-treated, provided such subsequent
[[Page 399]]
welding or brazing does not produce a temperature in excess of 400
deg.F. in any part of the top or bottom material.
(7) Repair of cylinders must be followed by a proof pressure leakage
test at prescribed test pressure and visual examination for weld quality
when welding on pressure parts of cylinders of plain carbon 0.25 percent
or less and manganese 1.00 percent or less, or when repairing steel
types 1315, NAX and GLX by the following procedure:
(i) Leakage through the welding metal may be repaired without
subsequent reheat treatment of the cylinder.
(ii) Repair permitted only by either the metal arc or tungsten inert
gas shielded arc process. E7015, 7016, or 7018 electrodes not larger
than \1/8\ inch diameter shall be used for the metal arc process.
(iii) Weld defects must be removed by grinding or chipping before
repair by the metal arc process. The tungsten inert gas shielded arc
process may be used for repair only when such repair can be made by
puddling. Repair weld shall not exceed 1 inch in length nor be closer
than 3 inches to the next repair area.
(iv) Repair of weld defects which have any cracking is not
permitted.
(j) Repair of non-pressure attachments. Repair of non-pressure
attachments by welding or brazing without affecting a pressure part of
the cylinder must be followed by visual examination for weld quality.
(KB) Prohibited repairs. Walls, heads or bottoms of cylinders with
injurious defects or leaks in base metal shall not be repaired, but may
be replaced as provided for in paragraph (l) of this section.
(l) Rebuilding of DOT-4 series and DOT-8, welded or brazed
cylinders. Rebuilding of DOT-4 series and DOT-8 series, welded or brazed
cylinders is authorized. Such rebuilding must be done by a manufacturer
of these types of DOT cylinders or by a repair facility approved by the
Associate Administrator for Hazardous Materials Safety and by a process
similar to that used in its original manufacture and under the following
specific requirements:
(1) The replacement of a pressure part such as wall, heads, or
bottoms of cylinders or the replacement of the porous filling material,
shall be considered as rebuilding.
(2) Rebuilt cylinders shall be considered as new cylinders and shall
conform to all the requirements of the specifications applying,
including verification of material, examination, inspection, etc., and
the rendering of the proper reports to the purchaser, cylinder
rebuilder, and the Associate Administrator for Hazardous Materials
Safety. Report must show that cylinders were rebuilt.
(3) Information in sufficient detail regarding previous serial
numbers and identification symbols must be filed with the Associate
Administrator for Hazardous Materials Safety.
(Approved by the Office of Management and Budget under control number
2137-0022)
[29 FR 18671, Dec. 29, 1964. Redesignated at 32 FR 5606, Apr. 5, 1967]
Editorial Note: For Federal Register citations affecting
Sec. 173.34, see the List of CFR Sections Affected appearing in the
Finding Aids section of this volume.
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