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GB/T 8334-2022: Periodic inspection and evaluation of liquefied petroleum steel gas cylinders
GB/T 8334-2022
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 23.020.30
CCS J 74
Replace GB/T 8334-2011
Periodic inspection and evaluation of liquefied petroleum
steel gas cylinders
ISSUED ON: MARCH 9, 2022
IMPLEMENTED ON: OCTOBER 1, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 4
1 Scope ... 6
2 Normative references ... 6
3 Terms and definitions ... 7
4 Inspection items ... 7
5 Inspection preparation ... 7
5.1 Records ... 7
5.2 Treatment of residual liquid and residual gas in the bottle ... 8
5.3 Cylinder valve disassembly and surface cleaning ... 8
6 Appearance inspection and evaluation ... 8
6.1 Initial inspection and evaluation of appearance ... 8
6.2 Appearance re-inspection and evaluation ... 9
7 Valve seat inspection and evaluation ... 11
7.1 Inspection content and evaluation method ... 11
7.2 Thread repair ... 11
8 Determination of wall thickness ... 11
8.1 Measurement requirements ... 11
8.2 Evaluation of results ... 11
9 Volume measurement (supplementary testing) ... 12
9.1 General provisions ... 12
9.2 Scale requirements ... 12
9.3 Numerical processing ... 12
9.4 Measurement and result evaluation ... 12
10 Hydrostatic test ... 12
10.1 Test requirements ... 12
10.2 Evaluation of results ... 12
11 Cylinder valve inspection, renewal, and assembly ... 13
11.1 Cylinder valve inspection ... 13
11.2 Cylinder valve renewal ... 13
11.3 Cylinder valve assembly ... 13
12 Air tightness test ... 13
12.1 Test requirements ... 13
12.2 Evaluation of results ... 14
13 Work after inspection ... 14
Appendix A (Informative) Methods for measuring depth values of dents, pits, gouges,
and scratches ... 15
Appendix B (Normative) Method for measuring the volume of water in steel cylinders
... 17
Periodic inspection and evaluation of liquefied petroleum
steel gas cylinders
1 Scope
This document specifies the basic methods and technical requirements for periodic
inspection and evaluation of liquefied petroleum gas cylinders (hereinafter referred to
as cylinders) designed and manufactured in accordance with GB/T 5842.
This document is applicable to steel cylinders that can be used at normal ambient
temperatures of -40 °C to 60 °C, with a nominal working pressure of 2.1 MPa and a
nominal volume not greater than 150 L, which can contain liquefied petroleum gas
repeatedly.
2 Normative references
The following documents contain the provisions which, through normative reference in
this document, constitute the essential provisions of this document. For the dated
referenced documents, only the versions with the indicated dates are applicable to this
document; for the undated referenced documents, only the latest version (including all
the amendments) is applicable to this document.
GB/T 3864 Industrial Nitrogen
GB/T 5842 Liquefied petroleum steel gas cylinders
GB/T 7512 Valves for liquefied petroleum gas cylinders
GB/T 8335 Special threads for gas cylinders
GB/T 8336 Special thread gauges for gas cylinders
GB/T 9251 Methods for hydrostatic test of gas cylinders
GB/T 10878 Special taps of taper threads for gas cylinders
GB/T12137 Methods for leakage test of gas cylinders
NB/T 47013.2 Nondestructive testing of pressure equipment - Part 2: Radiographic
testing
NB/T 47013.4 Nondestructive testing of pressure equipment - Part 4: Magnetic
5.2 Treatment of residual liquid and residual gas in the bottle
5.2.1 Before the steel cylinder inspection, under the premise of ensuring no leakage, no
pollution to the environment, and no impact on the health of the operators, use
appropriate methods to recover the residual liquid and residual gas in the cylinders one
by one. For steel cylinders whose cylinder valves cannot be opened and it is impossible
to prove whether there is residual pressure, they shall be stored separately from the
cylinders to be inspected, and marked for proper disposal. For the steel cylinders that
are judged to be waste by visual inspection, the residual liquid and residual gas in the
cylinders shall also be recovered one by one.
5.2.2 The residual liquid and residual gas in the cylinder shall be disposed of by purging
the cylinder with steam or by a method that does not affect the safety performance of
the steel cylinder after the safety assessment.
5.2.3 When using steam to purge the cylinder, the steel cylinder shall be placed upside
down on the steam purging device. Generally, the steam pressure shall be greater than
or equal to 0.2 MPa, and the purging time shall not be less than 3 min.
5.2.4 Use a combustible gas detector to measure the concentration of residual gas after
purging in the cylinder. For steel cylinders with a concentration higher than 0.4%
(volume fraction), the residual liquid and residual gas in the cylinder shall be treated
again.
5.3 Cylinder valve disassembly and surface cleaning
5.3.1 When confirming that the pressure inside the bottle is consistent with the
atmospheric pressure, remove the cylinder valve with an instrument that does not
damage the metal of the bottle body.
5.3.2 For steel cylinders whose cylinder valves cannot be opened, a reliable valve-
removal device shall be used to remove the cylinder valves. The valve-removal device
shall have the functions of being safety explosion-proof and preventing the medium in
the bottle from leaking into the atmosphere.
5.3.3 Use a surface treatment device that does not damage the cylinder body, and
remove the rust and coating on the outer surface of the cylinder one by one.
6 Appearance inspection and evaluation
6.1 Initial inspection and evaluation of appearance
Visually inspect the outer surface defects that are easy to find one by one, and any steel
cylinder that falls under one of the following conditions shall be rejected:
a) Steel cylinders whose shields are screwed to the cylinder body;
b) Steel cylinders where the shield falls off or its welded joints are broken, and
the butt joint of the cylinder body is cracked;
c) Steel cylinders whose upright standing is affected due to base detachment,
deformation, corrosion, cracks, wear, and other defects;
d) Steel cylinders that have undergone welding, repairing, patching, dismantling,
and refurbishment.
6.2 Appearance re-inspection and evaluation
6.2.1 Visual inspection of appearance
Visually inspect the steel cylinders one by one to check whether there are cracks, bulges,
wrinkles, interlayers, pits, gouges, scratches, dents, corrosion, heat damage, and other
defects on the outer surface of the cylinders, and check the shape of the base and the
cylinder body. For parts with pits, gouges, scratches, and corrosion defects found in the
appearance inspection, the minimum wall thickness of the bottle wall at the defect shall
be measured with an ultrasonic thickness measuring instrument.
6.2.2 Inspection and evaluation of mechanical damage
6.2.2.1 Steel cylinders with defects such as cracks, bulges, wrinkles, interlayers, and
volume deformation visible to the naked eye shall be rejected.
6.2.2.2 Steel cylinders with gouges, scratches and pits, at which the remaining wall
thickness is less than the design wall thickness, shall be rejected (see Appendix A for
the measurement method).
6.2.2.3 Steel cylinders with a depth of dent not less than 6 mm or greater than 1/10 of
the short diameter of th...