ISO 08795:2001 pdf download
ISO 08795:2001 pdf download.Plastics piping systems for the transport of
water intended for human consumption一 Migration assessment一Determination of migration values of plastics pipes and fittings and their joints.
5.2 General requirements for the liquids
The test liquid shall contain negligible concentrations of any measurable substances that could interfere with the measurements of constituents.
5.3 Selection of test liquids to perform the test
5.3.1 For cold water applications the test liquid(s) shall be selected from those given in 5.1.
5.3.2 For warm and hot water applications (see clause 6) the test liquid shall conform to 5.1 .1.
6 Test temperatures
Unless otherwise specified in the referring standard or regulations, the test temperature shall be selected from the following:
a) for cold water applications: (23 ± 2) °C;
b) for warm water applications: either (60 ± 2) °C or (70 ± 2) °C, depending upon the class of pipe;
c) for hot water applications: (90 ± 2) °C;
d) for tropical conditions: (27 ± 2) °C.
7 Apparatus
7.1 Connections, stoppers and containers, made of material which is inert at the specified test conditions, such as glass or PTFE or stainless steel (see also annex B).
NOTE The material PTFE should only be used when there is a small contact area with the test liquid, thus not for containers.
7.2 Thermostatically controlled environment or enclosure, capable of maintaining the relevant test temperature(s) (see clause 6).
8 Test pieces
8.1 General
8.1.1 Sampling of products shall be performed in accordance with the relevant product standard or system standard, as applicable.
NOTE National regulations for sampling may be applicable.
8.1.2 If it is necessary to store samples before testing, they shall be protected from contamination. If the manufacturer provides written instruction on storage, they shall be followed.
The samples shall be stored in their original form as delivered. Where appropriate, storage containers shall be cleaned using the same procedures as are used for test containers.
8.1.3 The test pieces shall be prepared such that only the surfaces intended to come into contact with the water are exposed to test liquids conforming to 5.1. Where the composition of the test pieces is homogeneous, i.e. the inside surface is the same as the outside surface, it is acceptable to immerse the whole test piece(s) in the test liquid.
If the surface area of the product in contact with drinking water consists of more than one material, then the product may be tested as a single unit or the individual materials can be tested either by disassembling the product or by using the procedure in 8.1.4 for each material.
8.1.4 If the procedure for the preparation of a test piece for a particular type of product or material has not been covered in this standard, deviation from this procedure is permitted under the following conditions:
a) the finished product and the test piece shall be produced in the same manner;
b) the preparation of test pieces before testing shall include the procedures, which are performed in practice before the system is put into operation, e.g. curing and cleaning procedures.
8.1.5 The surface of the test pieces intended to come into contact with the test liquids shall be free from adhesive tape, labels, ink or pencil marks.
NOTE Care may be necessary to ensure that the transport conditions do not influence the test results.
8.1.6 The minimum age of the test pieces shall be in accordance with the relevant product standard, system standard or, if not given in such a standard, with that recommended by the manufacturer for the product to be ready for use.
8.2 Preparation
8.2.1 Surface-area-to volume ratio (S/i)
The value of S/V shall not be less than 5 (dm1), where:
S is the inner surface area of the test piece, in square decimetres (dm2), exposed to the test liquid;
V is the volume of the test liquid, in litres.
8.2.2 Pipes
For each test, take length(s) of pipe sufficient to give the volume of the test liquid necessary to determine the amount of any migrated constituent(s) with the required accuracy.
For pipes with nominal sizes in excess of 80, the test arrangement shall be adjusted to one of the methods as given in annex B to meet the requirements of 8.2.1.
8.2.3 Fittings and joints
8.2.3.1 For each test take a fitting or joint or a number of fittings or joints, sufficient to give the volume of the test liquid, necessary to determine the amount of any migrated constituent(s) with the required accuracy.
If it is not possible to carry out this procedure due to practical reasons (e.g. geometry of the fitting or joint) the procedures described in 8.2.3.2 or 8.2.3.3 shall be applied.
