ISO 9809-1:2019 pdf download – Gas cylinders – Design, construction and testing of refillable seamless steel gas cylinders and tubes一 Part 1: Quenched and tempered steel cylinders and tubes with tensile strength less than 1 100 MPa.
NOTE When the test pressure has decreased a revision of the type approval certificate could be needed.
j) the guaranteed minimum yield strength, Rg and/or the guaranteed minimum tensile strength, Rmg. for the finished cylinder have changed.
lithe diameter of the internal thread has increased by less than 50% then:
k) in case of tapered threads the torque test shall be performed (see 92.5).
I) In case of parallel threads the calculation of the shear strength shall be performed (see 92.6).
lithe diameter of the internal thread has increased by 50 % or more, the pressure cycling test on two cylinders shall also be performed (see 92.2).
In both cases the new diameter shall be reported In the revised type approval certificate.
9.2 Prototype tests
9.2.1 General requirements
A minimum o150 cylinders or 15 tubes which are guaranteed by the manufacturer to be representative of the new design, shall be made available for prototype testing. However, if for special applications the total number 01 cylinders required is less than 50, a sufficient number of cylinders shall be made to complete the prototype tests required, in addition to the production quantity, but in this case, the approval validity is limited to this particular production batch.
In the course of the type approval process, the inspector shall select the necessary cylinders for testing and
a) verify that:
— the design conforms to the requirements of Clause 7:
— the thicknesses of the walls and ends on two cylinders (those taken for mechanical testing) meet the requirements of 7.3 to 7.6. the measurements being taken at least at three transverse sections of the cylindrical part and on a longitudinal section of the base and head;
— the requirements of Clause 6 are complied with;
— the requirements of 2.6. 7.7. 7.8 and 8.5 to 8.9 Inclusive are complied with for all cylinders selected for inspection;
— the Internal and external surfaces of the cylinders are free of any defect which might iiiake them unsafe to use (for examples, see Annex A).
b) supervise the following tests on the cylinders selected:
— the tests specified in 10.L2 a) (hydraulic burst test) on two cylinders, the cylinders bearing representative stamp markings;
— the tests specified in 10.1.2 b) (mechanical testing) on two cylinders, the test pieces being identifiable with the batch;
— the tests specified in 9.2.3 (base check) on the two cylinders selected for mechanical testing;
— the tests specified in 222 (pressure cycling test) on three cylinders, the cylinders bearing representative stamp markings;
— the tests specified in 92.4 (bend test and flattening test) on two cylinders, the test pieces being identifiable with the batch. Either two bend tests (see in a circumferential direction, or one flattening test (see 9.24.2) or one ring flattening test (see This can be on the same cylinders as those taken for mechanical testing;
— the geometrical requirements (or the neck thread are complied with for all cylinders selected for inspection
— the tests specified in 92.5 (torque test for taper thread only) on one cylinder, being identifiable with the batch or 9.2k (shear stress calculation for parallel threads)
9.2.2 Pressure cycling test
This test shall be carried out on cylinders bearing representative markings with a noncorroslve liquid subjecting the cylinders to successive reversals at an upper cyclic pressure, which is equal to the hydraulic test pressure, Ph• The cylinders shall withstand 12 000 cycles without failure.
For cylinders with a hydraulic test pressure Ph > 450 bar, the upper cyclic pressure may be reduced to two thirds of this test pressure. In this case, the cylinders shall wIthstand 80000 cycles without failure.
The value of the lower cyclic pressure shall not exceed 10 % of the upper cyclic pressure but shall have an absolute maximum of 30 bar.
The cylinder shall actually experience the maximum and minimum cyclic pressures during the test.
The frequency of reversals of pressure shall not exceed 0,25 Hz (15 cycles/mm). The temperature measured on the outside surface of the cylinder shall not exceed 50°C during the test.
After the test, the cylinder bases shall be sectioned to measure the thickness and to ensure that this thickness is sufficiently close to the minimum thickness prescribed in the design and shall be within the usual production tolerances. In no case shall the actual base thickness (a1 or b depending on the shape of the base) exceed the minimum value(s) specified on the drawings by more than 15%.
The test shall be considered satisfactory if the cylinder attains the required number of cycles without developing a leak.
9.2.3 Base check
A meridian section shall be made in the base centre of the cylinder and one of the surfaces thus obtained polished for examination under a magnilication of between x5 and xlO.
The cylinder shall be regarded as defective if the presence of cracks is detected. It shall also be regarded as defective if the dimensions of any pores or inclusions present reach values considered to pose a threat to safety.