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1、BRITISH STANDARD BS 7720:1995 Specification for Non-biological sterilization indicators equivalent to the bowie and dick test UDC 615.478.73-032.23:620.16.05 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 10:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7
2、720:1995 This British Standard, having been prepared under the direction of the Sector Board for Materials and Chemicals, was published under the authority of the Standards Board and comes into effect on 15 December 1995 BSI 03-1999 First published September 1994 Second edition December 1995 The fol
3、lowing BSI references relate to the work on this standard: Committee reference LBI/35 Draft for comment 92/58870 DC ISBN 0 580 25134 9 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee LBI/35, Sterilizers, autoclaves and di
4、sinfectors, upon which the following bodies were represented: Association of British Health Care Industries British Dental Trade Association Central Sterilising Club Department of Health Health and Safety Executive Infection Control Nurses Association Institute of Hospital Engineering Medical Steril
5、e Products Association National Blood Authority Public Health Laboratory Service Royal College of Pathologists Royal Pharmaceutical Society of Great Britain Society for General Microbiology The following bodies were also represented in the drafting of the standard, through a subcommittee: BLWA Ltd.
6、(The Association of the Laboratory Supply Industry) European Sterilization Packaging Association (UK) Amendments issued since publication Amd. No.DateComments Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 10:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS
7、7720:1995 BSI 03-1999i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2References1 3Definitions1 4General system requirements1 5Indicator system format2 6Performance2 7Packaging, labelling and instructions for use3 Annex A (normative) Method of determining strength after s
8、team sterilization6 Annex B (normative) Method of estimating the visual difference between the colour of the substrate and the changed (or unchanged) indicator reagent on the substrate6 Annex C (normative) Method of demonstrating uniform colour change on exposure to dry saturated steam8 Annex D (nor
9、mative) Method of comparing the sensitivity of the alternative pack system to the standard test pack when air is injected into the steam exposure apparatus8 Annex E (normative) Method of comparing the sensitivity of the alternative pack system to the standard test pack when residual air is allowed t
10、o remain within the steam exposure apparatus9 Annex F (normative) Method of determining the sensitivity of the indicator system under exposure to dry heat9 Annex G (normative) Method of demonstrating the shelf life of the product10 Annex H (normative) Steam exposure apparatus10 Annex J (normative) S
11、tandard test pack11 Annex K (informative) Air injection system11 Annex L (normative) Standard test cycles12 Figure 1 Example of a suitable format for additional marking5 Figure K.1 Air injection apparatus12 Figure L.1 Example of sub-atmospheric pulsing cycle13 Figure L.2 Example of sub- and super-at
12、mospheric pulsing cycle14 Table B.1 Values of spectral product required of the reflectance photometer at the given values of wavelength and illuminance7 List of referencesInside back cover Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 10:29:56 GMT+00:00 2006,
13、Uncontrolled Copy, (c) BSI BS 7720:1995 ii BSI 03-1999 Foreword This British Standard has been prepared by Technical Committee LBI/35 and specifies the requirements for non-biological indicators for particular application in the performance of the Bowie and Dick test. This edition of BS 7720 superse
14、des BS 7720:1994, which is withdrawn. The issue of a new edition is intended to remedy several minor ambiguities, omissions and cross-referencing errors in the original standard. The non-biological indicators specified in this standard are not intended for use in any process other than that specifie
15、d. The use of an inappropriate indicator may give dangerously misleading results. The performance of a non-biological indicator may be affected by the conditions of storage prior to use, the methods of use and the conditions of storage after exposure to the process. For these reasons, the recommenda
16、tions of the manufacturer for storage and use should be followed precisely. Non-biological indicators should not be used beyond any expiry date stated by the manufacturer. The Bowie and Dick test was conceived as a test for air removal from high vacuum porous load sterilizers 1. A successful Bowie a
17、nd Dick test indicates rapid and even penetration of steam into the test pack. The presence of air within the pack, due either to an inefficient air removal stage or an air leak during this stage, or non-condensable gases in the steam supply, can lead to failure of the test. The results of the test
18、may also be affected by other factors which inhibit steam penetration. The test does not necessarily demonstrate either achievement of the required temperature or maintenance of that temperature for the required time to achieve sterilization. A failure of the Bowie and Dick test is not conclusive pr
19、oof that the fault in the sterilizer is due to air retention, air leakage or non-condensable gases and other causes of failure may need to be investigated. The Bowie and Dick test is a performance test for steam sterilizers for wrapped goods. As such it is performed during the demonstration of confo
20、rmity of steam sterilizers to EN 2851) and as a routine test of performance in BS EN 554. The method of carrying out the test is described in EN 2851). A test pack for the Bowie and Dick test consists of two components: a) a system or device providing resistance to air removal (test load); and b) a
21、chemical indicator to detect the presence of steam. The Bowie and Dick test, as originally described 1, utilized Huckaback Towels as the material for the test load. The test as described in EN 2851) uses cotton sheets for this purpose. Alternative indicator systems for the Bowie and Dick test which
22、use different materials for the test load and employ indicator systems specifically formulated for use within defined test loads are available. This British Standard specifies requirements for the performance of the indicator system in combination with the test load with which it is intended to be u
23、sed. The indicator specified in this British Standard is intended to indicate when steam penetration has been inadequate. Product certification. Users of this British Standard are advised to consider the desirability of third party certification of product conformity to this British Standard based o
24、n testing and continuing product surveillance, which may be coupled with assessment of a suppliers quality systems against the appropriate Part of BS EN ISO 9000. 1) In preparation. It is envisaged that a British Standard implementing the European Standard will be published in due course. Licensed C
25、opy: London South Bank University, London South Bank University, Fri Dec 08 10:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7720:1995 BSI 03-1999iii Enquiries as to the availability of third party certification schemes are forwarded by BSI to the Association of British Certification Bodies. I
26、f a third party certification scheme does not already exist, users should consider approaching an appropriate body from the list of Association members. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their cor
27、rect application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, pages 1 to 14, an inside back cover and a back cover. This standard has been updated (see copy
28、right date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 10:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv blank Licensed Copy: London Sout
29、h Bank University, London South Bank University, Fri Dec 08 10:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7720:1995 BSI 03-19991 1 Scope This British Standard specifies requirements for an indicator system to be used within an indicator as an alternative to the Bowie and Dick test for steam
30、 sterilizers for wrapped goods and porous loads. An indicator system conforming to this standard is used in combination with a specified material which is used as a test load. This standard does not specify requirements for the test load but specifies the performance of the indicator system in combi
31、nation with the test load with which it is intended to be used. The indicator system specified in this standard is intended to identify poor steam penetration but does not necessarily indicate the cause of this poor steam penetration. 2 References 2.1 Normative references This British Standard incor
32、porates, by reference, provisions from specific editions of other publications. These normative references are cited at the appropriate points in the text and the publications are listed on the inside back cover. Subsequent amendments to, or revisions of, any of these publications apply to this Brit
33、ish Standard only when incorporated in it by updating or revision. 2.2 Informative references This British Standard refers to other publications that provide information or guidance. Editions of these publications current at the time of issue of this standard are listed on the inside back cover, but
34、 reference should be made to the latest editions. 3 Definitions For the purposes of this British Standard, the following definitions apply. 3.1 graduated response progressive visible change occurring on exposure to one or more process variables allowing assessment of the level achieved 3.2 defined e
35、nd-point visible change occurring after exposure to the specified variable(s) at a level equal to or greater than that specified for the indicator 3.3 indicator reagent active ingredient or combination of ingredients before conversion into the indicator 3.4 indicator system combination of the indica
36、tor reagent and its substrate 3.5 indicator indicator system in the form in which it is intended to be used 3.6 pre-assembled pack indicator in which the indicator system is incorporated into the test load during the manufacturing process and which is supplied ready for use 3.7 process indicator ind
37、icator intended for use with individual packs of product to demonstrate that the pack has been exposed to the sterilization process 3.8 user-assembled pack indicator for which the user combines the indicator system and the test load prior to use 3.9 sterilization temperature minimum temperature of t
38、he sterilization temperature band NOTEThe sterilization temperature band is the range of temperatures which may prevail throughout the load during the holding time. 3.10 temperature depression the thermodynamic temperature difference, in kelvin, given by (temperature in degrees Celsius at centre of
39、standard test pack minus temperature in degrees Celsius in active drain) 4 General system requirements 4.1 Documentation 4.1.1 The manufacturer shall establish, document and maintain a formal quality system to cover all operations required by this standard. NOTEBritish Standards of the BS 5750 and B
40、S EN ISO 9000 series, BS 7501, BS 7502, BS EN 45003, and BS 7511 to BS 7514 describe requirements for quality systems for manufacture and testing. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 10:29:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7720:1995 2
41、BSI 03-1999 4.1.2 Suitable records shall be maintained to ensure that, in the event of a defect arising, faulty batches can be recalled from use. 4.1.3 The manufacturing and distribution records shall be retained for a period of 5 years, or twice the declared shelf life of the product, whichever is
42、greater. These records shall be maintained in accordance with the requirements of 4.1.6 of BS EN ISO 9001:1994. 4.1.4 The quality system shall ensure that an acceptable quality level (AQL) of 1.0 or less is maintained for performance requirements. NOTEThe AQL is the maximum number of defects per 100
43、 units that, for the purposes of sampling inspection, can be considered satisfactory as a process average. 4.2 Labelling Where a date is required on labelling or information supplied with the product, this shall be expressed in accordance with BS EN 28601:1992. 4.3 Test methods NOTEThe test methods
44、specified in this standard are reference methods. When alternative methods are used routinely these should be defined, validated and have known correlation with the reference method. Test samples shall be conditioned in accordance with BS EN 20187:1993 prior to testing for performance. 4.4 Change af
45、ter exposure The change which occurs after exposure of the indicator system to the specified conditions shall be clearly visible to the naked eye and shall be either from light to dark or shall be a change from one colour to a distinctly different colour. 4.5 Marking for use For pre-assembled packs,
46、 each indicator shall be clearly marked with the process for which it is intended to be used (see also 7.2). 4.6 Toxicity The manufacturer shall retain documentary evidence that the indicator does not release any substance known to be toxic, in sufficient quantity to cause a health hazard, before, d
47、uring or after the sterilization process for which it is designated. 4.7 Permanence 4.7.1 The condition of the indicator system after exposure to a sterilization process, during which all the variables met or exceeded the specified level to produce a defined end-point or known graduated response, sh
48、all remain visually unchanged for a period of not less than 6 months from the date of use, when stored under the conditions specified by the indicator manufacturer. 4.7.2 The manufacturer shall state any change which may occur on storage of the indicator, after use, for periods greater than 6 months
49、 when stored under the conditions specified by the manufacturer (see 7.1.1 k). NOTEIncompletely changed indicators may deteriorate on storage; either returning to the unchanged condition or slowly completing the change reaction. If this occurs it should be stated by the manufacturer (see 7.1). Such indicators may not be suitable for use as a permanent record. 5 Indicator system format 5.1 Basic indicator requirements The indicator system shall: a) consist of an indicator reagent uniformly distributed on a substrate to cover not less than 20 % of the printed surface