BS 6256-2021 pdf free download.Packaging for terminally-sterilized medical devices — Method for determination of methylene blue particulate penetration
5.6 Rotary suction pump.
5.7 Air drier,
6 Procedure
6.1 Preliminary
6.1.1 FlI the atomlzer with a 1% methylene blue solution up to a level 6 mm below that of the spray orifice approximatly 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 methyleme blue soluton in the atmzer with the standand nozzle is consumed at a ruteof opproximatey 10 ml per hour This loss i8 due in part to the atomization of the solutiomn and in purt to the woporaton of water from the main buk of the Mquid. The ccntroationon of the solutom w the nesernolr terefore increuses sedily during the operation ofthe apperturs. The volume of the reservir o chosen s0 thot the change cmnrotion and loss of volwme. of the solucton during a perind of 8 h operation or less wll mot couse ppreciable change in the concentrotiom of the tert cod
6.2 Start-up instructions
6.2.1 Start up the apparatus as fllows
a) Tur the control cock (C) to OFE
b) Switch on the sucton punp.
d) Close and clamp the unloaded test piece holder (T).
d) Clamp the unloaded test paper holder (F) frmly closed.
e) Turm the control cock (C) to TEST.
f) Adjust the air valve [VJ to give a flow of 30 dm/min through the bypass circuit,
g) Turm the control cock (C如OFR
h) Adljust control valve (VJ to give a flow of 30 dm/min through the test circuit
i) Turn on the compressed air to the atomizer and adjust the neelle valve (V) until the presure gauge (D) registeres 205 kPa. The ball in the compressed alr fowmeter (M) should now rise to the calibration mark. If the air flow is insufcient, turn off the compressed air and clear the atomizer jets.
NOTEI Steps e) to ) establih the mominal air valve sts to ghve the required flow rates m subsequnt operations. Minor adjustment omly from these sttings can be mode
NOTE2 Ror details of maintemance, see Cuvese
6.2.2 Maintaln the alr pressure at a constant of 205 kPa. The alr pressure is not to be Increased to bring the air flow up to the correct value.
6.3 Preparation of standard stains
Prepare the standard stains a fllows
a] Close and clamp the unloaded test picce holder.
b) Clamp a short piece of fiter paper in the test paper holde.
e) Turn the control cock (C) to TEST for 20 s. During this period check, and adjust if necessary. the air valve (V) In the test cdrut to give a flow rate of 30 dm/min.
d) Turn the control cock (C) to OFF.
e) Unclamp the test paper holder and discard the piece of filter paper.
f) Insert and clamp in the test paper holder the end of a 300 mm length of filter paper.
g) Turn the control cock (C) to TESt hold for 1 s and then turn to OFF.
h) Unclamp the test paper holder, move the strip 25 mm to one side and reclamp.
1) Repeat steps g) and h) but for 2 s duration.
j) Repeat the sequence, increasing the duration of the run by 1 s on each up to 10 s.
k) Remove the filter strip and expose it to a jet of steam until the intensity of the stains is fully developed.
NOTE This filter strip, with 10 stains of increasing intensity, is tue standard test strip against which the test stains are compared. The 1 second stain is equivalent to a 2.5% penetration when the test is run for 40£ Successive stains represent increments of a 2.5% penetration so that (he 10 second stain corresponds o a 25% penetration.
6.4 Preparation of test stains
6.4.1 Prepare the test stains as follows:
a) cut two test pieces from the specimen to be tested, each 400 mm x 400 mm. and condition them in accordance with 13S EN 20187 for not less than 24 h. Carry out the remainder of the test within 10 nuns of removal of the test pieces from the conditioning atmosphere;
b) turn the control cock (C) to OFF;
c) clamp a test piece into its holder such that the wire side is challenged by the test cloud;
d) clamp a short length of filter paper into the test paper holder;
e) turn the control cock (C) to TEST and after 10 s to OFF. During this period, check, and, if nccessar adjust the flow rate of the test circuit to 30 dm3/minute;
f) discard the piece of filter paper and replace with a fresh piece;
g) turn the control cock (C) to TEST and after 40 S turn to OFF;
h) remove the test piece and the piece of filter paper. Develop the stain on the filter paper using a jet of steam; and
i) repeat steps c) to h) using the other test piece and testing the other side of the specimen.
6.4.2 Under the identical lighting conditions, compare the test stains with the standard stains and visually match them.BS 6256 pdf download.