Standard

NS-EN 838:1995

Withdrawn

Note: This standard has a new edition: NS-EN 838:2010

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Abstract

1.1 General This European Standard specifies performance requirements and test methods under prescribed laboratory conditions for a diffusive sampler used for the determination of gases or vapours in workplace atmospheres. Additional tests designed to establish whether the performance characteristics of the diffusive sampler are affected by the wider range of environmental influences that may be encountered in field use are described in annexes C and D. If there is no diffusive sampler for measuring a particular chemical agent which meets the requirements of this European Standard, it is recommended to use a diffusive sampler whose performance is nearest to the specified requirements. 1.2 Field of application The European Standard is applicable to: - type A samplers: diffusive samplers which are used for the direct determination of concentrations, for example, length-of-stain detector tubes; - type B samplers: diffusive samplers which are used for the indirect determination of concentration by sampling and analysis in separate stages. Type B samplers may be further divided into: - type B 1 samplers: diffusive samplers which rely on sorption onto a solid, resorption with solvent, and subsequent analysis of the desorbate; - type B 2 samplers: diffusive samplers which rely on sorption onto a solid, resorption by heat, and analysis of the desorbate; - type B 3 samplers: diffusive samplers which rely on sorption into a liquid, and subsequent analysis of the solu-tion. Specific aspects of the use of reagent impregnated systems will be covered in additional parts of this standard. 1.3 Object of standard This European Standard should enable manufacturers and users of diffusive samplers to adopt a consistent approach to sampler validation and provide a framework for the assessment of sampler performance against criteria specified in EN 482. It is the responsibility of the manufacturer or of those who assemble the diffusive samplers to ensure that the sampler complies with the overall uncertainty requirements under the specified laboratory conditions given in- this European Standard including such environmental influences, (e. g. temperature and humidity) that may be expected to affect performance. No useful performance requirements can be given for the effect of interferents (with the exception of water vapour). However, the user of diffusive samplers should be cautioned that interferences may occur especially for type A samplers. Such information shall be included in the instructions for use. If it is known in advance that a certain type of diffusive sampler is unaffected by an environmental influence, then the relevant tests in 7.7 to 7,9, or the equivalent in annex E shall be modified to examine only the factors likely to have an influence. NOTE 1: Annexes C and D relating to field tests are not obligatory as part of this European Standard but are directed primarily to the users of such devices, who are in the best position to know the specific factors that may significantly affect sampler performance. NOTE 2: Because of the known effect of pressure on diffusion coefficients, a pressure testis not necessary.

Document information

  • Standard from SN
  • Published:
  • Withdrawn:
  • Edition: 1
  • Version: 1
  • Document type: NAT
  • ICS 13.040.30
  • National Committee SN/K 508

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