ISO 19918:2017 pdf free
ISO 19918:2017 pdf free.Protective clothing – Protection against chemicals
The permeation cell consists of a base and a cylinder that are assembled with three bolts to form a cell. The centre of the base and the bottom surface of the cylinder are raised to improve contact between the two surfaces. See Annex B for a technical drawing, including measurements for the permeation cell. The gasket, collector disc, and test specimen are placed between the base and the cylinder. The test specimen’s normal inside surface is in contact with the collector disc. The material’s outer surface is toward the side that faces the test cylinder. The two pieces are connected with three bolts. The top surface of the cylinder has a spout to make it easier to drain the test chemical. The schematic diagram of the permeation cell is shown in Annex A.
The cylindrical, hollow insert illustrated in Figure B.4 fits into the centre of the cell. The insert is to maintain contact between the collector disc and the test specimen while the cell is being assembled. It shall be filled to bring the mass to (100±1)g.
See Annex B for the drawing and description of PTFE cell used for the interlaboratory study.
Measurements (including tolerance limits) in Figures B.2 to B.4 pertain to the cell in Annex B.
NOTE 1 Annex C includes a list of suppliers for the PTFE permeation cell, gaskets, and collector discs.
NOTE 2 Cells made with other materials and designs have not been tested.
NOTE 3 Other cells with similar design that give equivalent results could also be used.
The gasket shall be used to prevent leakage. Care shall be taken to ensure that test chemical cannot leak out of the challenge side of the apparatus, flow around the edge of the test specimen, and then leak into the collection side. This is most likely to happen by capillary action if the outer side of a multicomponent material is from woven or nonwoven material. The size of the gasket may be changed to control leakage.Information on selection and size of gaskets is included in Annex D.ISO 19918 pdf download.
