Marking of UN bundles of cylinders
Individual cylinders in a bundle of cylinders shall be marked in accordance with 184.108.40.206.
Refillable UN bundles of cylinders shall be marked clearly and legibly with certification, operational,
and manufacturing marks. These marks shall be permanently affixed (e.g. stamped, engraved, or
etched) on a plate permanently attached to the frame of the bundle of cylinders. Except for the UN
packaging symbol, the minimum size of the marks shall be 5 mm. The minimum size of the UN
packaging symbol shall be 10 mm.
The following marks shall be applied:
(a) The certification marks specified in 220.127.116.11.2 (a), (b), (c), (d) and (e);
(b) The operational marks specified in 18.104.22.168.3 (f), (i), (j) and the total of the mass of the frame of
the bundle and all permanently attached parts (cylinders, manifold, fittings and valves). Bundles
intended for the carriage of UN 1001 acetylene, dissolved and UN 3374 acetylene, solvent free
shall bear the tare mass as specified in clause B.4.2 of ISO 10961:2010; and
(c) The manufacturing marks specified in 22.214.171.124.4 (n), (o) and, where applicable, (p).
The marks shall be placed in three groups:
(a) The manufacturing marks shall be the top grouping and shall appear consecutively in the
sequence given in 126.96.36.199.3 (c);
(b) The operational marks in 188.8.131.52.3 (b) shall be the middle grouping and the operational mark
specified in 184.108.40.206.3 (f) shall be immediately preceded by the operational mark specified in
220.127.116.11.3 (i) when the latter is required;
(c) Certification marks shall be the bottom grouping and shall appear in the sequence given in
2 Distinguishing sign of the State of registration used on motor vehicles and trailers in international road traffic,
e.g. in accordance with the Geneva Convention on Road Traffic of 1949 or the Vienna Convention on Road Traffic of
Equivalent procedures for conformity assessment and periodic inspection and test
For UN pressure receptacles the requirements of 18.104.22.168 and 22.214.171.124 are considered to have been
complied with when the following procedures are applied:
Type approval (126.96.36.199)
Supervision of manufacture (188.8.131.52)
Xa or IS
Initial inspection and tests (184.108.40.206)
Xa or IS
Periodic inspection (220.127.116.11)
Xa or Xb or IS
Xa means the competent authority, its delegate or inspection body conforming to 18.104.22.168, 22.214.171.124,
126.96.36.199 and 188.8.131.52 and accredited according to EN ISO/IEC 17020:2012 (except clause 8.1.3) type A.
Xb means inspection body conforming to 184.108.40.206, 220.127.116.11, 18.104.22.168 and 22.214.171.124 and accredited according
to EN ISO/IEC 17020:2012 (except clause 8.1.3) type B.
IS means an in-house inspection service of the applicant under the surveillance of an inspection body
conforming to 126.96.36.199, 188.8.131.52, 184.108.40.206 and 220.127.116.11 and accredited according to EN ISO/IEC
17020:2012 (except clause 8.1.3) type A. The in-house inspection service shall be independent from
design process, manufacturing operations, repair and maintenance.
General requirements for non-UN pressure receptacles
Design and construction
Pressure receptacles and their closures not designed, constructed, inspected, tested and approved
according to the requirements of 6.2.2 shall be designed, constructed, inspected, tested and approved
in accordance with the general requirements of 6.2.1 as supplemented or modified by the requirements
of this section and those of 6.2.4 or 6.2.5.
Whenever possible the wall thickness shall be determined by calculation, accompanied, if needed, by
experimental stress analysis. Otherwise the wall thickness may be determined by experimental means.
Appropriate design calculations for the pressure envelope and supporting components shall be used to
ensure the safety of the pressure receptacles concerned.
The minimum wall thickness to withstand pressure shall be calculated in particular with regard to:
- The calculation pressures, which shall not be less than the test pressure;
- The calculation temperatures allowing for appropriate safety margins;
- The maximum stresses and peak stress concentrations where necessary;
- Factors inherent to the properties of the material.
For welded pressure receptacles, only metals of weldable quality whose adequate impact strength at
an ambient temperature of –20 °C can be guaranteed shall be used.
For closed cryogenic receptacles, the impact strength to be established as required by 18.104.22.168.8.1 shall
be tested as laid down in 22.214.171.124.
Acetylene cylinders shall not be fitted with fusible plugs.