BS EN ISO 7233:2021 Rubber and plastics hoses and hose assemblies一 Determination of resistance to vacuum

BS EN ISO 7233:2021 pdf free.Rubber and plastics hoses and hose assemblies一  Determination of resistance to vacuum.
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1402. Rubber and plastics hoses and hose assemblies — Hydrostatic testing ISO 8330. Rubber and plastics hoses and hose assemblies — Vocabulary
ISO 23529. Rubber — General procedures for preparing and conditioning test pieces for physical test methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8330 apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
4 Principle
The test methodology for determining the resistance to vacuum of plastic and rubber hoses and hose assemblies consists of reducing the internal pressure in a length of hose by means of a vacuum pump and gauge, while examining the hose for any signs of deformation or delamination of reinforcement or lining.
5 Apparatus
5.1 Vacuum pump, provided with a gauge and capable of reducing the internal pressure in the hose within 60 s to the pressure specified in the product standard (or, if no product standard is applicable, the pressure agreed between the parties) for the hose under test and maintaining it at that pressure for a minimum of 10 min.
5.2 Smooth, solid ball (for method A), with a diameter equal to 0,9 times the bore of the hose under test, rounded down to the nearest whole millimetre.
5.3 Two transparent airtight plates (for method B), for sealing each end of the hose. One of the plates shall permit attachment of the vacuum pump to the hose, while allowing internal visual inspection of the hose during the test.
6 Test pieces
If the complete hose or hose assembly is more than 1 m long, each test piece shall consist of a minimum length of hose, clear of the end fittings, of 1 m. If the complete hose or hose assembly is less than 1 m long, the complete length shall be used.
7 Conditioning of test pieces
No tests shall be carried out within 24 h of manufacture. Test pieces shall be conditioned at the appropriate temperature in accordance with ISO 23529 for at least 3 h before testing.
This 3 h period may form part of the minimum period of 24 h between manufacture and testing.
8 Test pressure
The internal pressure to which the hose or hose assembly is subjected to for the duration of the test shall be that stated in the product standard for the hose or hose assembly under test as being the minimum internal pressure which the hose or hose assembly is required to withstand.
9 Procedures
9.1 Method A
Lay out the hose as straight as possible on a flat surface and blank off one end to form an airtight seal. Insert into the hose a smooth, solid ball (5.2) before assembling the hose and then connect the open end of the hose or hose assembly to a vacuum pump and gauge. Reduce the pressure in the hose or hose assembly within 60 s to the required test pressure and maintain this pressure for the required period, which shall not be less than 10 mm.
While the test pressure is being maintained, examine the hose externally for any signs of resulting irregularities, flaws or collapse and then tilt the hose to permit the solid ball to traverse the full length of the hose or hose assembly to check for any obstructions caused by internal deformation or delamination.
9.2 Method B
Lay out the hose or hose assembly as straight as possible on a flat surface and fit transparent airtight plates (3) to both ends of the hose or hose assembly, one of which shall then be connected to a vacuum pump and gauge. Reduce the pressure In the hose or hose assembly within 60 s to the required test pressure and maintain this pressure for the required period, which shall not be less than 10 mm.
While the test pressure is being maintained, examine the interior of the hose or hose assembly through one of the transparent plates by means of illumination supplied through the transparent plate at the other end of the hose for signs of delamination or blistering of the lining. Also examine the exterior of the hose or hose assembly for signs of resulting irregularities, flaws or collapse.
9.3 Method C
Lay out the hose or hose assembly as straight as possible on a flat surface, seal one end airtight and connect the other end to a vacuum pump and gauge.
Before reducing the pressure in the hose or hose assembly, mark in accordance with ISO 1402.
10 Test report
The test report shall contain the following information:
a) the number and year of publication of this document, i.e. ISO 7233:202 1;
b) a full description of the hose or hose assembly tested;
c) the method of test used;
d) the internal test pressure applied, expressed in kPa (and bar) absolute;
e) the period for which the test pressure was applied;
f) observations on the behaviour of the hose or hose assembly during the test, including any external signs of resulting irregularities, flaws or collapse and, if method A was used, whether or not the ball traversed the full length of the test piece or, if method B or C was used, whether or not lining delamination or blistering was observed;
g) If method C was used, the percentage change in the length (temporary and permanent) of the hose or hose assembly when the pressure was reduced and after the pressure was released, calculated according to 9.3;
h) if method C was used, the percentage change in the outside diameter (temporary and permanent) of the hose or hose assembly when the pressure was reduced and after the pressure was released, calculated according to 9.3;
i)any deviations from the procedure;
j)the date of the test.BS EN ISO 7233 pdf free download.BS EN ISO 7233:2021 Rubber and plastics hoses and hose assemblies一 Determination of resistance to vacuum