BS 6256:2021 pdf download – Packaging for terminally-sterilized medical devices — Method for determination of methylene blue particulate penetration
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes provisions of this document 1) . For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. BS EN 20187, Paper, board and pulps – Standard atmosphere for conditioning and testing and procedure for monitoring the atmosphere and conditioning of samples 3 Terms and definitions No? terms? and? definitions? are? listed? in? this? document.
NOTE ISO and IEC maintain terminological databases for use in standardization at the following addresses: a) ISO Online browsing platform: available at https://www.iso.org/obp; and b) IEC Electropedia: available at http://www.electropedia.org/. 4 Principle COMMENTARY ON CLAUSE 4 The layout of the apparatus is illustrated in Figure 1 and Figure
2Normative references
The following documents are referred to in the text in such a way that some or all of theircontent constitutes provisions of this document.For dated references, only the edition citedapplies.For undated references, the latest edition of the referenced document (including anyamendments) applies.
BS EN 20187,Paper, board and pulps – Standard atmosphere for conditioning and testing andprocedure for monitoring the atmosphere and conditioning of samples
3Terms and definitions
No terms and definitions are listed in this document.
NOTE IS0 and lEC maintain terminological databases for use in standardization at the following addresses:a)ISo online browsing platform: available at https://www.iso.org/obp; and
b)IEC Electropedia: available at http://www.electropedia.org/
4 Principle
COMMENTARY ON CLAUSE4
The layout of the apparatus is illustrated in Figure 1 and Figure 2,
The atomizer, working under a constant pressure and flow of compressed air, disperses a solution ofmethylene blue into a mist at a uniform rate.The mist passes into the evaporation tube(E) where it isdiluted to a total volume of 30 dm3/min by dry air entering at (B).The droplets of solution evaporatebefore reaching the control cock (C), leaving a residue of solid particles of methylene blue.Whenthe control cock (C) is in the test position, the test cloud passes to the test circuit which contains thesample under test and the filter paper.
When the control cock is turned to the central or air position, the cloud is diverted to the by-passcircuit and at the same time air is drawn through the test circuit. In the off position of the controlcock, the cloud remains diverted to the by-pass circuit, but there is no flow through the test circuit.The rates of flow in the circuits are adjusted to 30 dm3/min by means of the air valves V, and vg
To test a sample, the control cock is first turned to the off position and the sample and filter paper areinserted into their respective holders. The test cloud is then passed to the sample for a predeterminedtime, following which air is passed for a further period of 2 s in order to sweep out the residual cloudfrom the test circuit. The control cock is then turned to off and the filter paper removed.Finally thetest stain is developed with steam and the penetration assessed by comparing the stain with thestandard stains.
5 Apparatus, components and layout
NOTESee Annex A and Figure 1,
5.1Test cloud generator, comprising the atomizer (A), needle valve (V,), pressure gauge (D), compressed air flowmeter (M ) and evaporation tube (E).
5.2Control cock (C).
5.3Test circuit, comprising test piece holder (T), test paper holder (F), flowmeter (M,) and control valve (v,).
5.4Bypass circuit, comprising the filter (G), flowmeter (M,) and control valve (V,).5.5 Filter paper (3).
6 Procedure
6.1 Preliminary
6.1.1 Fill the atomizer with a 1 % methylene blue solution up to a level 6 mm below that of the spray orifice:
approximately 500 ml of solution are required.
6.1.2 After a maximum of 8 h operation, discard the methylene blue solution and replace with a fresh 1%
solution of methylene blue.
NOTE The methylene blue solution in the atomizer with the standard nozzle is consumed at a rate ofapproximately 10 ml per hour.This loss is due in part to the atomization of the solution and in part to the
evaporation of water from the main bulk of the liquid. The concentration of the solution in the reservoir thereforeincreases steadily during the operation of the apparatus. The volume of the reservoir is chosen so that the changein concentration, and loss of volume, of the solution during a period of 8 h operation or less, will not cause anappreciable change in the concentration of the test cloud.