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BRITISH STANDARD BS EN 285:1997
Sterilization — Steam sterilizers — Large sterilizers
The European Standard EN 285: 1996 has the status of a British Standard
Committees responsible for this British Standard
The preparation of this British Standard was entrusted to Technical Committee LBF35, Sterilizers, autoclaves and disinfectors, upon which the following bodies were represented:
ABHI Special Interest Section (Sterilizers and Disinfectors)
Association of British Healthcare Industries
Association of Clinical Pathologists
British Dental Trade Association
Central Sterilising Club
Department of Health
Health and Safety Executive
Infection Control Nurses Association
Institute of Healthcare Engineering and Estate Management
Institute of Sterile Services Management
Medical Sterile Products Association
Public Health Laboratory Service
Royal College of Pathologists
Royal Pharmaceutical Society of Great Britain
Society for General Microbiology
Contents
Page
Committees responsible Inside front cover
National foreword____________________________________________ ii
Foreword 2
Text of EN 285_ _____________________________________________ 3
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 September 1997
© BSI1997
The following BSI references relate to the work on this standard:
Committee reference LBI/35
Draft for comment 92/58124 DC
ISBN 0 580 27635 X
National foreword
This British Standard has been prepared by Technical Committee LBF35, and is the English language version of EN 285 : 1996 Sterilization — Steam sterilizer's — Large stettiizers, published by the European Committee for Standardization (CEN). It supersedes BS 3970: Part 3 : 1990, which is withdrawn. It also supersedes the current provisions of BS 3970: Part 1: 1990, which is subject to amendment
Steam sterilizers falling within the scope of this standard are considered to be medical devices under Directive 93/42/EEC and compliance with the requirements of the standard is a means of ensuring that particular essential requirements of the Directive are met (see annex ZA of this standard).
Attention is drawn to United Kingdom statutory requirements pertaining to sterilizers and their use. Attention is also drawn to the guidance contained within Health Technical Memorandum (HTM) 2010, published by the Department of Health.
ISO 228-1 BS 2779 : 1986 Specification for pipe threads for tubes and
fittings wJiere pressure-tight joints are not made on the threads (metric dimensions)
EN ISO 3746 : 1995 BS EN ISO 3746 : 1996 Acoustics. Determination of sound
power levels of noise sources using sound pressure. Survey method using an enveloping measurement surface over a reflecting plane
ISO 4017 BS EN 24017 : 1992 Hexagon head screws. Product grades A
andB
Compliance with a British Standard does not of itself confer immunity
from legal obligations.
Cross-references
Publication referred to Corresponding British Standard
BS EN 10088 Stainless steels
EN 10088-1 BS EN 10088-1: 1995 List of stainless steels
EN 10088-2 BS EN 10088-2 : 1995 Technical delivery conditions for sheet/plate and strip for general purposes
EN 10088-3 BS EN 10088-3 : 1995 Technical delivery conditions for semi-finished products, bars, rods and sections for general purposes
BS EN 50081 Electromagnetic compatibility.
Generic emission standard
EN 50081-1 BS EN 50081-1: 1992 Residential, commercial and light industry
EN 50081-2 BS EN 50081-2 : 1994 Industrial environment
BS EN 50082 Electromagnetic compatibility.
Genetic immunity standard
EN 50082-1 BS EN 50082-1: 1992 Residential, commercial and light industry
EN 50082-2 BS EN 50082-2 : 1995 Industrial environment
BS EN 60204 Safety of machinery.
Electrical equipment of machines
EN 60204-1: 1992 BS EN 60204-1: 1993 Specification for general requirements
BS EN 60584 Thermocouples
EN 60584-2 : 1993 BS EN 60584-2 : 1993 Tolerances
EN 60651:1994 BS EN 60651: 1994 Specification for sound level meters
EN 60751:1995 BS EN 60751: 1996 Industrial platinum resistance thermometer sensors
EN 60804 :1994 BS EN 60804 : 1994 Specification far integrating-av^aging sound level meters
BS EN 61010 Safety requirements for electrial equipment for measurement, control and laboratory use
EN 61010-1 BS EN 61010-1: 1993 General requirements
EN 61010-2-041 BS EN 61010-2-041: 1997 Particular requirements for autoclaves using steam for the treatment of medical materials, and for laboratory processes
EUROPEAN STANDARD EN 285
NORME EUROPEENNE
EUROPAISCHE NORM October 1996
ICS 11.080
Descriptors: Sterilization, medical equipment, sterilizers, water vapour, equipment specifications, locking devices, doors, fittings, measuring instruments, indicating instruments, specifications
English version
Sterilization — Steam sterilizers — Laige sterilizers
Sterilisation - Sterilisateurs a la vapeur d'eau — Sterilisation — Dampf-Sterilisatoren —
Grands Sterilisateurs Grofi-Sterilisatoren
This European Standard was approved by CEN on 1996-09-14. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
European Committee for Standardization Comite Europeen de Normalisation Europaisches Komitee fur Normung
Central Secretariat: rue de Stassart 36, B-1050 Brussels
Foreword
This European Standard has been prepared by Technical Committee CEN/TC 102, Sterilizers for medical purposes, Nthe secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by April 1997, and conflicting national standards shall be withdrawn at the latest by April 1997.
This European Standard has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s). For the relationship with EU Directive(s) see informative annex ZA, which is an integral part of this standard.
This European Standard specifies requirements and the relevant tests for large steam sterilizers. Specifications of requirements and tests for small steam sterilizers as well as for sterilizers using other sterilants than steam are in preparation by CEN/TC 102.
This European Standard does not specify requirements for the validation and routine control of sterilization by moist heat. A European Standard specifying requirements for the validation and routine control of sterilization by moist heat was prepared by CEN/TC 204, Sterilization of medical devices, see EN 554 Sterilization of medical devices — Validation and routine control of sterilization by moist heat. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.
Contents
Page
Foreword 2
1 Scope 3
2 Normative references 3
3 Definitions 4
4 Mechanical components 5
5 Process components 7
6 Instrumentation - Indication and
registration devices 8
7 Control sytems 13
8 Performance requirements 14
9 Sound power 15
10 Rate of pressure change 15
11 Safety 15
12 Marking 15
13 Service and local environment 15
14 Installation checks 17
15 Categories of tests 17
16 Test programmes 17
17 Microbiological tests 19
18 Thermometric tests 20
19 Bowie and Dick test 23
20 Air leakage test 23
21 Air detector tests 24
22 Load dryness tests 25
23 Sound power test 27
24 Steam quality tests 28
25 Dynamic sterilizer chamber pressure
test 35
26 Test apparatus, equipment and
material 35
27 Documentation 39
28 Information 39
Annexes
A (informative) Recommended materials 40
B (informative) Suggested maximum
values of steam contaminants 42
C (informative) Bibliography 43
ZA (informative) Clauses of this European Standard addressing essential requirements or other provisions of
EU Directives 44
1 Scope
1.1 This European Standard specifies requirements and the relevant tests for large steam sterilizers primarily used in health care for the sterilization of one or more sterilization modules for wrapped goods (instruments etc. and porous loads).
Large steam sterilizers can also be used during the commercial production of medical devices.
NOTE. Sterilizers conforming to this standard can offer a single automatic sterilization cycle or a number of selectable automatic sterilization cycles, e.g. with different operating temperatures (see 28.3b)].
1.2 This European Standard is not applicable to small steam sterilizers or to steam sterilizers used for the sterilization of pharmaceutical products in containers.
NOTE. The use of sterilizers for unwrapped instruments and utensils for immediate use in aseptic areas and for fluid-sterilizers will be the subject of a separate standard.
1.3 This European Standard does not describe a quality assurance system for the control of all stages of the manufacture of the sterilizer.
NOTE. Attention is drawn to the standards for quality systems (see EN ISO 9001, EN ISO 9002, EN ISO 90044 and EN 46001 and EN 46002).
2 Normative references
This European Standard incorporates, by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies.
prEN 866-1 Biological systems for testing
sterilizers — Part 1: General requirements
prEN 866-3 Biological systems for testing
sterilizers — Part 3: Particular systems for use in steam sterilizers
prEN 867-3 Non-biological systems for use in
sterilizers — Part 3: Specification for class B indicators for use in the Bowie and Dick test
prEN 868-5 Packaging materials for sterilization
of wrapped goods — Part 5: Heat scalable pouches and reel material of paper and plastic construction — Requirements and tests
EN 10088-1 Stainless steels — Part 1: List of
stainless steels
EN 10088-2 Stainless steels — Part 2: Technical
delivery conditions for sheet/plate and strip for general purposes
EN 10088-3 Stainless steels — Part 3: Technical
delivery conditions for semi-finished products, bars, rods and sections fen" general purposes
EN 50081-1 Electromagnetic compatibility —
Generic emission standard — Part 1: Residential, commercial and light industry
EN 50081-2 Electromagnetic compatibility —
Generic emission standard — PaH 2: Industrial environment
EN 50082-1 Electromagnetic compatibility —
Generic immunity standard — Part 1: Residential, commercial and light industry
EN 50082-2 Electromagnetic compatibility —
Generic immunity standard — Part 2: Industrial environment
EN 60204-1: Safety of jnachinery — Electrical,
1992 equipment of machines —
Part 1: General requirements
(IEC 204-1: 1992, modified)
EN 60584-2: Tliermocouples — Part 2: Tolerances
1993 (TEC 584-2 : 1982 + Al: 1989)
EN 60651:1994 Sound level meters
(IEC 651: 1979 + Al: 1993)
EN 60751: 1995 Industrial platinum resistance thei^nometej" sensors (IEC 751: 1983 + Al : 1986)
EN 60804:1994 Integrating-averaging sound level
meters (IEC 804: 1985 + Al : 1989)
EN 61010-1 Safety requirements for electrical equipment for measurement, control and laboratory use — Part 1: General requirements (IEC 1010-1: 1990 + Al : 1992, modified) EN 61010-2-041 Safety requirements for electrical equipment for measurement, control and laboratory use - Part 2-041:
Particular requirements fen- autoclaves using steam for the treatment of medical materials, and for laboratory processes (IEC 1010-2-041:1996) IEC 38 IEC standard voltages
ISO 228-1 Pipe flireads where pressure-tight
joints are not made on the threads — Part 1: Dimensions, tolerances and designation
EN ISO 3746: Acoustics — Determination of sound
1995 power levels of noise sources using
sound pressure — Survey method using an enveloping measurement surface over a reflecting plane (ISO 3746: 1995)
ISO 4017 Hexagon head screws — Product grades A and B
3 Definitions
For the purposes of this standard the definitions of
EN 764 apply, together with the following.
NOTE. Other definitions relevant to validation are given in EN 554.
3.1 active drain
Drain which is situated at the lowest part of the sterilizer chamber to control the discharge of air/non-condensable gases or air and condensate from the sterilizer chamber.
3.2 air removal
Removal of air from the sterilizer chamber and sterilizer load sufficient to facilitate steam penetration.
3.3 automatic controller
Device that, in response to pre-determined cycle variables, operates the sterilizer sequentially through the required stages of the cycle(s).
3.4 biological indicator
An inoculated carrier contained within its primary pack ready for use (prEN 866-1).
3.5 calibration
The set of operations that establish, under specified conditions, the relationship between values of a quantity indicated by a measuring instrument or measuring system, or values represented by a material measure or a reference material, and the corresponding values realized by standards.
3.6 chamber depth
Depth of the sterilizer chamber which is available for the sterilizer load.
3.7 chamber height
Height of the sterilizer chamber which is available for the sterilizer load.
3.8 chamber width
Width of the sterilizer chamber which is available for the sterilizer load.
3.9 chamber temperature
Lowest temperature prevailing in the sterilizer chamber (EN 554).
3.10 cycle complete
Indication that the sterilization cycle has been satisfactorily completed and that the sterilized load is ready for removal from the sterilizer chamber.
3.11 dedicated steam supply
Supply of steam produced for a sterilizer, or group of sterilizers, by a dedicated generator.
3.12 door
Lid or similar device provided as a means of closing and sealing the sterilizer chamber.
3.13 double ended sterilizer
Sterilizer in which there is a door at each end of the sterilizer chamber.
3.14 dry saturated steam
Steam with a temperature and pressure corresponding to the vaporization curve of water.
NOTE. This is an ideal condition which can deviate towards either superheated steam or to wet steam. This deviation is quantified by the determination of the Dryness Value.
3.15 equilibration time
Period which elapses between the attainment of the sterilization temperature in the sterilizer chamber and the attainment of the sterilization temperature at all points within the load (EN 554).
3.16 fail safe
Attribute of sterilizer design, component or its associated services that minimizes a possible safety hazard.
3.17 fault
Recognition by the automatic controller that the pre-set cycle variables for the sterilization cycle have not been attained.
3.18 holding time
Period for which the temperature of all points within the sterilizer is held within the sterilization temperature band.
NOTE. The holding time follows immediately after the equilibration time. The extent of the holding time is related to the sterilization temperature.
3.19 inoculated carrier
A carrier on which a defined number of test organisms has been deposited (prEN 866-1).
3.20 installation test
Series of checks and tests performed after installation of the sterilizer in the place of use (EN 554).
3.21 loading door
Door in a double-ended sterilizer through which the sterilizer load is put into the sterilizer chamber prior to sterilization.
3.22 medical device
The definition given in EN 46001 applies.
3.23 non-condensable gas
Air and other gas which will not condense under the conditions of steam sterilization.
3.24 plateau period
Equilibration time plus the holding time.
3.25 pressure vessel
A vessel describing the sterilizer chamber, jacket (if fitted), door(s) and components that are in permanent connection with the sterilizer chamber.
3.26 reference measurement point
Reference point for which documented evidence is available to demonstrate that it has a known relationship to the temperature of the coolest part of the sterilizer chamber.
3.27 reference standard
Standard, generally having the highest metrological quality available at a given location or in a given organization, from which measurements made there are derived.
3.28 safety hazard
Potentially detrimental effect on persons or the surroundings arising directly from either the sterilizer or its load.
3.29 small steam sterilizer
Steam sterilizer which is unable to accommodate a sterilization module.
3.30 sterile
Condition of a medical device that is free from viable micro-organisms (EN 556).
3.31 sterilization
Process undertaken to render a sterilizer load sterile.
3.32 sterilization cycle
Automatic sequence of operating stages performed in a sterilizer for the purpose of sterilization (EN 554).
3.33 sterilization module
Rectangular parallelepiped of the dimensions
300 mm X 300 mm X 600 mm used for the puiposes of
sterilization.
3.34 sterilization temperature
Minimum temperature of the sterilization temperature band (EN 554).
3.35 sterilization temperature band
Range of temperatures, expressed as the sterilization temperature and the maximum allowable temperature which may prevail throughout the load during the holding time (EN 554).
NOTE. These temperatures are usually stated in whole degrees Celsius.
3.36 sterilizer
Apparatus designed to achieve sterilization.
3.37 sterilizer chamber
That part of the sterilizer which receives the sterilizer load (EN 554).
3.38 sterilizer load
Goods that are to be sterilized simultaneously in the same sterilizer chamber (EN 554).
3.39 superheated steam
Steam whose temperature, at any given pressure, is higher than that indicated by the vaporization curve of water.
3.40 test organism
Mcro-organisms used for the manufacture of inoculated carriers (prEN 866-1).
3.41 type test
Series of tests to establish the working data for a sterilizer type.
3.42 unloading door
Door in a double-ended sterilizer through which the sterilized load is removed from the sterilizer chamber after a sterilization cycle.
3.43 usable space
Space inside the sterilizer chamber which is not restricted by fixed parts and which is consequently available to accept the sterilizer load.
NOTE. The usable space is expressed in terms of chamber height, chamber width and chamber depth.
3.44 works test
Series of tests performed at the manufacturer's works to demonstrate compliance of each sterilizer with its specification.
4 Mechanical components
4.1 Dimensions
The usable space within the sterilizer chamber shall accommodate one or more sterilization modules.
4.2 Materials
Materials in contact with steam shall:
- resist attack from steam and condensate;
- not cause deterioration of the quality of the steam;
NOTE 1. Guidance is given in annex B.
- not release any substances known to be toxic in
such quantities as could create a health hazard.
NOTE 2. Because of the different types of sterilizers and the large number of uses, it is not possible to specify detailed requirements for materials for specific applications. The purchaser should provide the manufacturer with information about the goods to be sterilized.
NOTE 3. Advice on the various combinations of materials is given in annex A.
4.3 Pressure equipment
4.3.1 General
4.3.1.1 A Council Directive on the approximation of the laws of the member states concerning pressure equipment (see 93/C246/01) and corresponding European Standards are in preparation (CEN/TC 54 and CEN/TC 269). Until European Standards on pressure equipment are published, the pressure equipment should comply with national regulations and standards applying in the country of intended use.
4.3.1.2 Sterilizers shall be provided with one or two doors.
4.3.1.3 The door seal shall be a replaceable component.
It shall be possible to inspect and clean the surface of the door seal which comes into contact with the sealing faces without the need to dismantle the door assembly.
4.3.1.4 After closing the sterilizer door, it shall be possible to open it without having first to initiate a sterilization cycle.
4.3.1.5 Except in the case of a fault, it shall not be possible to open a sterilizer door(s) during a sterilization cycle.
4.3.2 Double-ended sterilizers
4.3.2.1 Except for maintenance purposes, it shall not be possible for more than one door to be open at one time.
4.3.2.2 It shall not be possible to open the unloading door until a 'cycle complete' indication is obtained.
4.3.2.3 It shall not be possible to open the unloading door if a Bowie and Dick test has been carried out
4.3.2.4 The control used to start the sterilization cycle shall be located at the loading side of the sterilizer.
4.3.3 Test connections
4.3.3.1 If the sterilization cycle includes a vacuum stage, a test connection in accordance with figure 1 shall be fitted to the sterilizer chamber or in a pipe which is in direct connection with the sterilizer chamber (excluding vacuum line). The test connection which is used for the connection of a test instrument shall be provided with a standard cap, marked VT (vacuum test) and sealed with either an O-ring-seal or a flat seal.
4.3.3.2 A straight connecting sleeve, in accordance with figure 2, shall be provided at a point of easy access in order to pass at least six flexible cords to the temperature sensors.
Figure 2. Connection sleeve for thermoelements
The connecting sleeve with its O-ring-seal or flat seal shall be closed with a standard cap, and a temperature proof and mechanically resistant soft packing. The cap shall be marked with the letters TT (temperature test).
4.3.3.3 Test tees and valve cocks with sealing plugs shall be fitted to permit connection of reference instruments for the calibration of all pressure instruments, connected to the sterilizer chamber and jacket (see 6.1.2 and 6.1.4).
4.3.4 Insulating material
Except where insulation would interfere with the function and operation of the sterilizer, external surfaces shall be insulated to minimize heat transmission to the environment such that the temperature of the outer surface of the insulating material does not exceed 55 °C when tested in an environmental temperature of (23 ± 2) °C.
4.4 Framework and panelling
4.4.1 Where the sides of the sterilizer are visible from the user area, they shall be enclosed with panelling. The manufacturer shall provide instructions for the cleaning of the panelling.
NOTE. The panelling should have a corrosion-resistant finish to the cleaning agents specified by the manufacturer.
4.4.2 The panelling of the sterilizer shall allow access for maintenance work (for example, by the use of a special key, code or tool). Such panelling shall be demountable or the dimensions of any personal access shall be not less than 500 mm wide and not less
than 1500 mm high, and the access shall not be obstructed.
NOTE 1. If the pressure equipment is housed in a frame, this frame should not promote corrosion of the equipment.
NOTE 2. The access for maintenance should be positioned so that it will not compromise the safety of either the product or persons.
4.4.3 The panelling shall be designed to provide a continuous contact with the surfaces of the building in which it is installed when these surfaces are within the tolerances given in tables 1 and 2.
Sterilizers designed for incorporation into existing buildings or purpose built rooms shall provide a continuous joint with adjacent surfaces when these are within the tolerances given in tables 1 and 2.
| Table 1. Tolerances for the aperture into which the sterilizer is installed |
||
| Dimension m |
Tolerance mm |
|
| Horizontal plane |
Vertical plane |
|
| up to 3 |
±12 |
±16 |
| above 3 to 6 |
±16 |
±16 |
| above 6 to 15 |
±24 |
±20 |
| above 15 to 30 |
±24 |
±20 |
| above 30 |
±30 |
±30 |
| Table 2. Tolerances for vertical and horizontal flatness |
||
| Distance between checkpoints m |
Tolerance mm |
|
| Finished surfaces of walls and ceilings |
Finished floor (bearing surface) |
|
| 0,1 |
3 |
2 |
| 1 |
5 |
4 |
| 4 |
10 |
10 |
| 10 |
20 |
12 |
| 15 |
25 |
15 |
5 Process components
5.1 Pipework and fittings
5.1.1 Pipe joints and fittings shall be both pressure-tight and vacuum-tight.
5.1.2 Except where this will interfere with the function of the sterilizer, the pipework for steam or water at a temperature greater than 60 °C shall be thermally insulated to minimize heat transmission to the environment The temperature of the outer surface