EN 838-1995 pdf download.Workplace atmospheres Diffusive samplers for the determination of gases and vapours Requirements and test methods.
5.2 Desorption efficiency (for type B 2 samplers)
When tested in accordance with 7.1.2. the desorption efficiency shall be 0,95 with a coefficient of variation of ≤ 0,1 at each loading.
5.3 Storage (for type B samplers) When tested in accordance with 7.9.1. the mean value of the recovery after storage shall not differ more than 10 % from the value before storage.
5.4 Overall uncertainty
When tested in accordance with 7.2, 7.7 and 7.8 the overall uncertainty calculated in accordance with 7.13 and 7.14 shall be as specified in EN 482. The manufacturer shall state the range of temperature and humidity over which the overall uncertainty requirement is met. The temperature range should be from 5 °C to 40 °C, but shall he at least from 10 °C to :30 °C. In this temperature range, and at relative humidity between 20 % and 80 % the overall uncertainty requirement shall be met without the use of correction factors. Outside the temperature range of 10 °C to 30 °C the requirement may be fulfilled by the use of correction factors.
5.5 Blank value
When tested in accordance with 7.4. the blank value shall be less than one-third of the calculated mass uptake by the sampler for 30 mm exposure to 0,1 LV.
5.6 Sampler leak test (only samplers not thermally sealed)
When tested in accordance with 7.10. any additional analyte determined above the blank value (see 5.5) shall be less than one-third of the calculated mass uptake by the sampler for 30 mm exposure to 0,1 LV.
5.7 Uptake rate value (for type B samplers) If it is possible to calculate the steady-state value in accordance with 7.3.2, the nominal uptake rate value determined in accordance with 7.3.1, shall be within ± 25 % of the ideal steady-state value.
5.8 Effect of air velocity/sampler orientation The minimum air velocity and influence of sampler orientation given in the manufacturer’s instructions for use shall be verified in accordance with 7.6.
5.9 Shelf life (for type A samplers) The shelf life of the diffusive sampler in the original package shall be as specified by the manufacturer. At the end of the shelf life, the results obtained in accordance with 7.11 shall not differ by more than 10 % from the original values.
5.10 Mechanical strength (for type A samplers) Following the tests in 7.12, the diffusive samplers shall maintain their physical integrity and the results obtained in accordance with 7.13 and 7.14 shall not differ by more than 10 % from the original values.
5.11 Instructions for use
The instructions for use supplied with the diffusive sampler shall be in the language(s) of the country where the diffusive sampler is to be marketed. It shall contain at least the following information:
a) uptake rate (measured or calculated) for a specific analyte;
b) designated use including level of evaluation; C) direction for proper handling of the diffusive sampler including opening and closing;
d) general information on the system e.g. sorbent; e) the levels at which other typical gases and vapours, including water, are likely to interfere to
the extent of increasing the overall uncertainty
above the level specified in this European
Sta ndarcl:
f) response time;
g) information on the calculation of results including evaluation of reading and correction factors for temperature and desorption efficiency, if applicable;
h) information on storage and transport; 1) minimum air velocity;
j) desorption efficiency;
k) information on the desorption method.
The general information on the system, d). can be given in additional literature.
5.12 Sample identification
The diffusive sampler shall have a suitable area for
sample identification by the user.
6 General test conditions
6.1 Reagents
Use only analytical grade reagents.
6.2 Apparatus
6.2.1 Usual laboratory apparatus and resources and:
6.2.2 A dynamic system for generating, pre-mixing and delivering a known concentration of a test gas or vapour in air (see Annex G for corresponding ISO Standards).EN 838-1995 pdf download.
EN 838-1995 pdf download
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