BS 6256 pdf free download

BS 6256:2021 pdf free.Packaging for terminally-sterilized medical devices – M lethod 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”. 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 puips – 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 data bas,es for use in standardization at the following addresses:
a) ISO Online browsing platform: available at https:/1wwwso.orgJobp and
b) IEC Electropedia: available at http://wwwelectropedia.org/.
4 Principle
COMMENTARY ON CLAUSE 4
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 of methylene blue into a mist at a uniform rate, The mist passes into the evaporation tube (E) where it is diluted to a total volume of 30 dm’/min by dry air entering at (B). The droplets of solution evaporate before reaching the control cock (C), leaving a residue of solid particles of methylene blue. When the control cock (C) is in the test position, the test cloud passes to the test circuit which contains the sample 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-pass circuit and at the same time air is drawn through the test circuit. In the ofT position of the control cock, 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 dm’/min by means of the air valves V2 and V3.
To test a sample, the control cock Is first turned to the off position and the sample and filter paper are inserted into their respective holders. The test cloud is then passed to the sample for a predetermined time, following which air is passed for a further period of 2 s in order to sweep out the residual cloud from the test circuit. The control cock is then turned to off and the filter paper removed. Finally, the test stain is developed with steam and the penetration assessed by comparing the stain with the standard stains.
5 Apparatus, components and layout
NOTE See Annex A and Figure 1
5.1 Test cloud generator, comprising the atomizer [A), needle valve (V,), pressure gauge (D), compressed air flowmeter (M) and evaporation tube (E).
5.2 Control cock (C].
5.3 Test circuit, comprising test piece holder (T), test paper holder (F), flowmeter (M) and control valve (V2).
5.4 Bypass circuit, comprising the filter (G), flowmeter (M_) and control valve (V3).
5.5 Filter paper (3).
5.6 Rotary suction pump.
5.7 Airdrier.
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 al methylene blue.
NOTE The methylene blue solution in the atomizer with the standard nozzle is consumed at a rate of approximately 10 rn/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 therefore increases steadily during the operation of the apparatus. The volume of the reservoir is chosen so that the chan.qe in concentration, and loss of volume, of the solution during a period of 8 h operation or less, will not cause an appreciable change in the concentration of the test cloud.
6.2 Start-up Instructions
6.2.1 Start up the apparatus as follows.
a) Turn the control cock (C) to OFF.
b) Switch on the suction pump.
c) Close and clamp the unloaded test piece holder (T).
d) Clamp the unloaded test paper holder (F) firmly closed.
e) Turn the control cock (C) to TEST.
f) Adjust the air valve (V2) to give a flow of 30 dm/min through the bypass circuit.
g) Turn the control cock (C) to OFF.
h) Adjust control valve (Vj to give a flow of 30 dm’/min through the test circuit.BS 6256 pdf download.