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BS ISO 16000-20:2014 pdf free

BS ISO 16000-20:2014 pdf free.Indoor air – Detection and enumeration of moulds – Determination of total spore count
The spores on the sticky surface are stained with e.g. lactophenol blue solution (see 5.2) or cotton blue in lactic acid and evaluated under the microscope at 400×and 1000×magnification.
NOTE 1 To get an overview of the sample trace, it can be useful to make an initial view at 100×or 200×magnification.If different volumes have been sampled, choose the most appropriate (enough spores, not overloaded) for counting.
NOTE 2 Counting of the different spore types under the microscope is a difficult task which can only be performed by skilled and well trained personnel.
NOTE 3 Lactophenol blue solution is toxic and has to be avoided whenever possible. Staining of spores with alternative staining solution has to be anticipated. Cotton blue in lactic acid does, however, not work with the PS 30 with MBASS303) which was used for determining the performance characteristics (see Clause 10).The slit impaction sampling method produces a sample trace approx. 1,6 cm long and approx. 1 mm wide on the glass slide which is evaluated by microscopy.
Normally, the slides are evaluated for the following spore types: Basidiospores, Ascospores,Cladosporium, type Aspergillus/Penicilium, Stachybotrys, Chaetomium, type Alternaria/Ulocladium, type Helminthosporium, Epicoccum, other spores, and mycelial fragments. Additional spore types which occur in unusual concentrations and can be assigned to a morphological type are likewise reported.
Basidiospores, ascospores, spores of the types Alternaria/Ulocladium, Helminthosporium, and Epicoccum do not usually originate from indoor sources and therefore provide an indication as to what extent the sample has been influenced by outdoor air (e.g. due to leaks around windows, mechanical disturbance of settled outdoor spores).
Large, readily recognizable spores, e.g. Stachybotrys or Chaetomium spores, are counted on the whole surface at 400×magnification in longitudinal direction of the sample trace. In this way, the complete loaded impaction surface can be evaluated within a reasonable time scale and hence, few spores determined per sample volume. The theoretical detection limit is one spore in the volume sampled.
For small spores of the type, e.g. Aspergillus/enicilium, an additional detailed evaluation is made at 1000×magnification in the direction perpendicular to the sample trace. Detailed evaluations are very time-consuming so that only a small portion of the sample (usually approx. 10 % to 30 % of the total impaction surface, see Clause 10) can be evaluated. Consequently, the detection limit for small spores is higher than that for large spores. For a sample volume of 200 L and the evaluation of 10 transverse traverses, the theoretical detection limit is approx.50 spores/ m3 (one spore present in the 10 traverses).BS ISO 16000-20 pdf free download.


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