1、BRITISH STANDARD BS 3970-2: 1991 Sterilizing and disinfecting equipment for medical products Part 2: Specification for steam sterilizers for aqueous fluids in sealed rigid containersBS3970-2:1991 This British Standard, having been prepared under the directionof the Laboratory Apparatus Standards Pol
2、icy Committee, was published underthe authority of the Standards Board and comes intoeffect on 30September 1991 BSI 02-1999 The following BSI references relate to the work on this standard: Committee reference LBC/35 Draft for comment 90/54474 DC ISBN 0 580 19797 2 Committees responsible for this Br
3、itish Standard The preparation of this British Standard was entrusted by the Laboratory Apparatus Standards Policy Committee (LBC/-) to Technical Committee LBC/35, upon which the following bodies were represented: Associated Offices Technical Committee Association of British Health-care Industries A
4、ssociation of British Sterilizer Manufacturers Association of National Health Service Supplies Officers British Dental Trade Association British Surgical Trades Association Central Sterilising Club Department of Health Health and Safety Executive Infection Control Nurses Association Institute of Hos
5、pital Engineering Institute of Purchasing and Supply Institute of Sterile Services Management Joint Committee of Professional Nursing, Midwifery and Health Visiting Associations (England) Medical Sterile Products Association National Blood Transfusion Service Public Health Laboratory Service Regiona
6、l Hospital Boards Engineers Association Royal College of Pathologists Royal Pharmaceutical Society of Great Britain Society for General Microbiology Stainless Steel Fabricators Association of Great Britain The following body was also represented in the drafting of the standard, through subcommittees
7、 and panels: Guild of Hospital Pharmacists Amendments issued since publication Amd. No. Date CommentsBS3970-2:1991 BSI 02-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 General requirements 2 4 Design pressure 2 5 Design of spray-jets 2 6 Opera
8、ting cycle 2 7 Instrumentation and controls 3 8 Performance requirements 4 9 Load-handling equipment 5 10 Information to be supplied by the manufacturer 5 Appendix A Recommendations for information to be supplied by the purchaser 6 Appendix B Test for sterilizer function without a load 6 Appendix C
9、Test for sterilizer function with a small load of low thermalcapacity 6 Appendix D Test for sterilizer function with a full load 7 Appendix E Test for coolant water quality 7 Appendix F Test for F subzero (F 0 ) control compliance 8 Appendix G Test for performance of reference instrument 8 Appendix
10、H Potential hazards associated with the sterilization ofaqueousfluidsin sealed rigid containers 9 Figure 1 Pressure generated in a nominal1L bottle, containing differentvolumes of water, when heated to121C 10 Table 1 Operating cycle conditions for acceptable temperature band 2 Table 2 Permitted rang
11、es for F 0values 5 Publication(s) referred to Inside back coverBS3970-2:1991 ii BSI 02-1999 Foreword It is recommended that this foreword be read in conjunction with the foreword to BS 3970-1. This Part of BS 3970 has been prepared under the direction of the Laboratory Apparatus Standards Policy Com
12、mittee. This Part and BS 3970-1:1990 together supersede BS 3970-2:1966, which is withdrawn. Parts 1 and 2 of the first edition of BS 3970 were both published in 1966 and covered two specific types of sterilizer. However, in this revision the structure of BS 3970 has been changed so that general requ
13、irements are now given in the revised (1990) edition of Part 1. Those requirements that are not common to most types of sterilizer are specified in subsequent Parts of this standard. These Parts giving particular requirements should be read in conjunction with BS 3970-1:1990, which they supplement o
14、r modify. The titles of these Parts are given in Part 1. When aqueous fluids in sealed rigid containers are heated, the increased pressure within them becomes a source of danger, especially when temperatures above80C are reached. Hence it is a requirement of this standard that the load in the chambe
15、r of the sterilizer shall remain inaccessible to the operator unless the temperature of all the contents of the load has become lower than80C. Appropriate interlocks on the door-controlling mechanisms are specified, together with appropriate temperature detectors. There are two accepted principles o
16、f exposing the load to a sterilization cycle that gives an adequate level of lethality, each involving the attainment of an adequate temperature for an adequate time. In Table 1 a preferred combination of time and temperature is given, this being entirely acceptable for thermo-stable products. Addit
17、ionally with thermo-labile products the user may choose to use the F 0principle in which other times and temperatures are employed. In this case the onus is on the User to determine the nature of the bioburden in the product(s) and also to determine that the proposed cycle will ensure that the proba
18、bility of survival of microorganisms does not exceed 10 6 . The F 0control function may be incorporated into the automatic controller. With thermo-labile products it will normally be appropriate to employ assisted cooling in order to limit thermal damage. It is also the responsibility of the user to
19、 provide a suitable container which will withstand the physical conditions and remain intact and sealed both during and after the process in order to prevent adulteration of the contents of the container during the process itself or any possible subsequent microbial contamination. The purchaser may
20、have to adjust the timing of the stages of the process when sterilizing a fluid with viscosity markedly higher than that of water. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Comp
21、liance 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 and ii, pages1to10, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have
22、 had amendments incorporated. This will be indicated in the amendment table on theinside front cover.BS3970-2:1991 BSI 02-1999 1 1 Scope This Part of BS 3970 specifies particular requirements for sterilizers intended to be used for the sterilization of aqueous fluids in sealed rigid containers in wh
23、ich the heat transfer is effected by saturated steam under phase-boundary conditions, having a steady-state equilibrium during the holding phase. These requirements apply in addition to the general requirements specified in BS3970-1. NOTE 1Recommendations for the information to be supplied by the pu
24、rchaser to the manufacturer are given in Appendix A. NOTE 2The attention of both the sterilizer manufacturer and the user is drawn to the hazards associated with processing fluids in sealed rigid containers described in Appendix H. NOTE 3The titles of the publications referred to in this standard ar
25、e listed on the inside back cover. 2 Definitions For the purposes of this Part of BS 3970 the definitions given in BS 3970-1 apply, together with the following. 2.1 acceptable temperature band the temperature range within which all parts of the load are to be maintained throughout the holding time (
26、see 2.8) of the operating cycle, there being a minimum acceptable temperature (see 2.13) and a maximum acceptable temperature 2.2 air ballasting a process whereby the chamber pressure is maintained at or near the pressure obtaining in the chamber during the steady-state stage (see 2.12) of the opera
27、ting cycle either during the whole of the cooling stage or during the initial part of it NOTEAlthough called air ballasting gases other than air may be suitable. 2.3 cooling stage the period of the operating cycle, after the holding time (see 2.8) has been completed, during which the load remains in
28、 the chamber, while the load cools to a temperature of80C or below 2.4 natural cooling mode a method of cooling in which the steam supply to the chamber is cut off and the sterilizer and its load allowed to cool to the required temperature by natural heat loss. This may take several hours to complet
29、e and is only suitable for loads with high thermal stability 2.5 assisted cooling any method of cooling in which, after the steam supply to the chamber has been shut off, the rate of heat loss from the load is increased significantly above the rate of natural cooling 2.6 rapid cooling assisted cooli
30、ng in which stage4of the operating cycle is completed in not more than45min when conducted with a fully loaded chamber NOTEA short period of natural cooling may precede assisted cooling or rapid cooling in stage4. 2.7 equilibration time the period which elapses between the attainment of the steriliz
31、ation temperature in the sterilizer chamber and the attainment of the sterilization temperature (see 2.13) at all points of the load 2.8 holding time the stage during which all parts of the chamber, load and any coolant fluid are at a temperature within the acceptable temperature band (see 2.1) 2.9
32、simulator a temperature-detecting device so constructed that its temperature relates to the thermal characteristics of a stated load container over part or all of the operating cycle NOTESterilizers may be fitted with more than one simulator. 2.10 simulator safety system a system or device incorpora
33、ting a simulator that prevents the operator opening the chamber door when the temperature of the load within the chamber exceeds80C 2.11 simulator control system a system or device that incorporates a simulator and that controls the equilibration time (see 2.7) so that the load achieves the necessar
34、y acceptable temperature band (see 2.1) for the required holding time (see 2.8) 2.12 steady-state stage the period that includes the equilibration time (see2.7) and the holding time (see 2.8)BS3970-2:1991 2 BSI 02-1999 2.13 sterilizing temperature the minimum temperature of the acceptable temperatur
35、e band (see 2.1) 3 General requirements 3.1 Unless otherwise specified in this Part of BS3970, sterilizers shall comply with BS 3970-1, and with 3.2 and clauses 4 to 10 of this Part of BS3970. NOTEUsers of this Part of BS 3970 are advised that reference should be made to the Electrical Safety Code f
36、or Hospital Laboratory Equipment (ESCHLE) as certain of its requirements are specified in BS 3970-1. 3.2 Unless otherwise stated in this standard, compliance with the requirements specified in this standard shall be checked by visual inspection and, if appropriate, by direct measurement. 4 Design pr
37、essure The design pressure of the vessel shall be not lower than1.6bar 1)and that of the jacket, if fitted, shall be not lower than2.6bar. If the acceptable temperature band is above the range121C to124C, the design pressure of the vessel shall be not lower than2.6bar and that of the jacket, if fitt
38、ed, not lower than3.6bar. 5 Design of spray-jets If spray-jets are fitted to provide rapid cooling of the load, means shall be provided to allow the functioning of each jet to be checked with the chamber door open. NOTEThese jets should be easily replaceable. 6 Operating cycle The sterilizer shall b
39、e capable of achieving the time-temperature relationship given in Table 1 and shall perform this and any alternative combination(s) of time and temperature (see note to Table 1) in the following sequence under automatic control. NOTE 1Guidance on the conditions for sterilization may be found in the
40、Rules Governing Medicinal Products in the European Community” Part IV “Guide to good manufacturing practice for medicinal products”. NOTE 2See also clause 8. Table 1 Operating cycle conditions for acceptable temperature band Stage 1. Heat up and air removal. Steam shall be admitted to, or be produc
41、ed in, the chamber to achieve phase-boundary conditions within the acceptable temperature band (see Table 1). Air shall be removed by trapping or by venting or steam purging, or additionally by means of vacuum pump(s). Stage 2. Equilibration time. During this stage all parts of the chamber exposed t
42、o steam shall be either at a temperature within the acceptable temperature band or higher than this. Stages2and3shall be controlled by means of one of the following: a) adjustable timers of an automatic controller in conjunction with temperature sensors within the chamber drain and within containers
43、 of the load (see 7.2.4); or b) under the control of a simulator control system;or c) by a F subzero (F 0 ) system. If this is fitted, the control function shall be limited to the initiation of stage4when a selected F 0value has been attained. Stage 3. Holding time. During this stage the temperature
44、 of all parts of the chamber exposed to steam, and the fluid in all containers comprising the load, and any coolant fluid, shall be within the acceptable temperature band. Stage3shall be maintained for either the specified holding time (seeTable 1), or shall be terminated when a preset value of F 0h
45、as been attained. 1) 1 bar = 10 5N/m 2= 10 5 Pa. Minimum temperature Maximum temperature Minimum holding time C C min 121 124 15 NOTEAlthough clause 6 requires the sterilizer to be capable of performing an operating cycle having the characteristics stated in this table, users may also wish a sterili
46、zer to be operated at other combinations of time and temperature. Such combinations of time and temperature may be used provided that it has been satisfactorily demonstrated that the process chosen delivers an adequate level of lethality. See also 7.5 a).BS3970-2:1991 BSI 02-1999 3 Stage 4. Cooling
47、stage. At the end of stage3, cooling shall be either by natural cooling or by assisted cooling. The simulator safety system shall maintain the door or doors in the locked position until the contents of all the containers comprising the load have cooled to80C or below. (See 7.6.) When assisted coolin
48、g is effected by means of a spray in the chamber, the spray shall be in operation throughout stages2and3of the operating cycle in order to expose the coolant to the sterilizing conditions of the cycle. The heat-exchanger for the coolant shall remain inoperative during stage2and stage3. Means shall b
49、e provided to ensure that there is sufficient coolant when the sterilizer is operated with either an empty chamber or with a small load. NOTE 3See 8.5 regarding the quality of water to be used by the cooling system. At the completion of each operating cycle, all liquid coolant shall be discharged as completely as practicable in order to avoid build-up of either microbial or particulate contaminants. NOTE 4When assisted cooling is effected by means of a liquid spray within the chamber, it may be necessary to maintain the pressure within the chamber by means of
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