1、BRITISH STANDARD AEROSPACE SERIES BS 5N 100-7:2002 Aircraft oxygen systems and equipment Part 7: Guide to cleaning labelling and packaging ICS 13.340.30; 49.080 BS 5N 100-7:2002 This British Standard, having been prepared under the direction of the Engineering Sector Policy and Strategy Committee, w
2、as published under the authority of the Standards Policy and Strategy Committee on 16 September 2002 BSI 16 September 2002 The following BSI references relate to the work on this British Standard: Committee reference ACE/38 Draft for comment 01/705553 DC ISBN 0 580 40165 0 Committees responsible for
3、 this British Standard The preparation of this British Standard was entrusted to Technical Committee ACE/38, Aircraft oxygen equipment, upon which the following bodies were represented: British Airways British Compressed Gases Association Civil Aviation Authority Health and Safety Executive Ministry
4、 of Defence Society of British Aerospace Companies Limited South Bank University Amendments issued since publication Amd. No. Date CommentsBS 5N 100-7:2002 BSI 16 September 2002 i Contents Page Committees responsible Inside front cover Foreword ii 1S c o p e 1 2 Normative references 1 3 Definitions
5、1 4G e n e r a l 2 5 Cleanliness limits 6 6 Verification of cleanliness 7 7 Aqueous-based cleaning procedures 8 8 Solvent cleaning procedures 10 9 Packaging 11 10 Labelling and storage 12 11 Unwrapping 12 Bibliography 15 Table 1 Materials for use as barrier 12 Table 2 Rigid container materials 12 Ta
6、ble 3 Gaskets and “O” rings (seals for rigid containers) 13BS 5N 100-7:2002 ii BSI 16 September 2002 Foreword This part of BS N 100 has been prepared by Technical Committee ACE/38 and specifies general requirements for oxygen systems and equipment for use on aircraft and ground support equipment. Th
7、is part provides guidance on cleaning procedures, labelling and packaging requirements. This revision supersedes BS 4N 100-7:1999 which is withdrawn. BS N 100 consists of the following parts: Part 1: Design and installation; Part 2: Tests for the compatibility of materials in the presence of oxygen;
8、 Part 3: Testing of equipment and systems; Part 4: Guide to the physiological factors; Part 5: Guide to fire and explosion hazards associated with oxygen; Part 6: Guidance and recommendations on the selection of materials for use with oxygen; Part 7: Guide to cleaning, labelling and packaging. NOTE
9、The prefix number before the “N” indicates the latest revision of an aerospace series standard. Insufficient cleanliness of components used in oxygen rich systems can result in ignition of the contaminants or the components by; for example, particle or mechanical impact, adiabatic compression, etc.
10、Control of contamination in oxygen enriched systems is essential to minimize hazards and component failures. Contamination also needs to be minimized to ensure the purity of the oxygen-enriched gases. The removal of contamination from materials and components is dependent on the system configuration
11、, the materials used in the construction, and the types and quantities of contaminants. Many cleaning agents used in the past for cleaning oxygen service components are now prohibited for use on account of environmental damage. It is necessary to consider many factors in selecting a suitable cleanin
12、g process that is environmentally friendly, non-injurious to health and cleans to an adequate standard. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself co
13、nfer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 15 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued.BS 5N 100-7:2002 BSI 16 September 2002
14、1 1 Scope This part of BS N 100 provides guidance on the selection of methods and apparatus for the cleaning, packaging and labelling of materials and equipment intended for service for airborne oxygen-enriched breathing systems, including oxygen storage and generation equipment. It is also applicab
15、le to associated ground support equipment and non-aerospace applications using oxygen equipment. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest
16、edition of the referenced document (including any amendments) applies. BS 1133-19, Packaging code Part 19: Use of desiccants in packaging. BS 2540, Specification for granular desiccant silica gel. BS 4N 100-2, Aircraft oxygen systems and equipment Part 2: Tests for the compatibility of materials in
17、the presence of oxygen. BS 5295-0, Environmental cleanliness in enclosed spaces Part 0: General introduction, terms and definitions for clean rooms and clean air devices. BS 5295-3, Environmental cleanliness in enclosed spaces Part 3: Guide to operational procedures and disciplines applicable to cle
18、an rooms and clean air devices. BS EN ISO 14644-4:2001, Cleanrooms and associated controlled environments Part 4: Design construction and startup. BS IEC 60877, Code of practice for procedures for ensuring the cleanliness of industrial process measurement and control equipment in oxygen service. BS
19、ISO 14951-10, Aerospace series Space systems Fluid characteristics Part 10: Water. DEF STAN 81-75, Issue 2, dated 25 July 97, Barrier Materials, Aluminium Foil Laminate, Flexible, Heat Sealable, Water Vapour Resistant. 3 Definitions For the purpose of this standard the following definitions apply. 3
20、.1 brush cleaning method of cleaning a hard-to-reach surface which involves physically brushing it with synthetic bristles soaked in solvent or cleaning agent 3.2 component individual part of a unit of two or more assembled parts which have been designed to allow disassembly for servicing 3.3 contam
21、inant foreign or unwanted substance that can have deleterious effects on the operation, life, safety, or reliability, of an oxygen service system 3.4 de-ionized water water, free of dissolved organics, particulates and ionized substances. It should have an electrical conductivity of 10 7 , 1 , cm 1o
22、r less, and have been passed through an activated carbon cartridge to remove organic contamination and particulates down to 50 m. 3.5 fibres particulate matter with a length of 100 m or more, and a length to width ratio of 10 to 1, or greaterBS 5N 100-7:2002 2 BSI 16 September 2002 3.6 high efficien
23、cy particulate air (HEPA) filter air filter which removes 0.3 m diameter particles with an efficiency that exceeds 99.97% (by volume) 3.7 non-metallics organic and inorganic materials such as ceramics, glasses, polymers, rubbers, greases and other lubricants, cloth, wool, and paper products 3.8 non-
24、volatile residues greases, such as hydrocarbon greases, fluorocarbon greases etc., cutting oils, cleaning agents after the volatile components have evaporated 3.9 oxygen clean component component or item to be used in an oxygen system, which has been specially cleaned to remove and/or substantially
25、reduce the concentrations of contaminants, in particular particles, fibres, greases and oils, to minimize the risks of fire and explosions occurring due to the presence of these contaminants; and which has been protected after cleaning from re-contamination by appropriate packaging, storage and warn
26、ing labels NOTE Oxygen cleaning is often carried out as an additional cleaning process after components, items, etc. have been cleaned, to remove burrs, swarf, flux, etc., to the appropriate engineering standards for non-oxygen systems. 3.10 particulate finely divided solid of organic or inorganic m
27、atter, including metals 3.11 wipe cleaning method of cleaning a surface which involves physically rubbing or swabbing it with a material such as cloth or paper moistened with, or soaked in, a cleaning solution or solvent 4 General 4.1 Work area 4.1.1 It is essential to maintain a clean work area to
28、ensure that cleaned oxygen service components remain clean until packaged or reassembled. Ideally, the work environment should be a clean room area in accordance with BS 5295 with facilities to handle the cleaned components without danger of re-contamination. Doors from the workroom should not open
29、to the weather and the room should be in an area remote from contaminants, particularly oil and grease. Assembly/disassembly benches should be clean and free from oil and grease and have a suitable covering which can easily be replaced. The air inside the room should be filtered to remove over 100 m
30、 size particles and smoking or eating in the room should not be permitted. Tools and equipment should be clean and maintained for use only with oxygen service equipment. The work area should be well ventilated if in situ solvent cleaning operations are being carried out, to ensure that occupational
31、exposure limits are not exceeded. 4.1.2 If the work room does not fully meet the requirements of BS 5295, a localized clean area for cleaning and assembling small components may be achieved using a laminar flow bench or cabinet. NOTE Although the level of cleanliness obtained in the local area will
32、be better than in the outside structure, it will be affected by the presence of high levels of particulates that can penetrate the laminar flow. 4.1.3 Personnel undertaking cleaning operations should have clean hands and should wear protective clean room grade gloves to prevent contamination of comp
33、onents after cleaning. If shoes are brought in from the outside, they should be covered to prevent the introduction of contamination into the workspace. Barrier, moisturising or cosmetic creams of any description should not be applied to the hands or face, etc., either whilst in the work area or bef
34、ore entering it. The protective clothing worn during cleaning should be lint free and not be worn when visiting other areas where industrial operations are taking place, particularly those associated with oil and grease. All lint producing clothing should be prohibited in the clean room area.BS 5N 1
35、00-7:2002 BSI 16 September 2002 3 4.2 Disassembly of systems 4.2.1 If construction permits, assembled systems should be fully disassembled for cleaning. Individual components of oxygen-enriched systems should be cleaned as separate items just prior to assembly or packaging. 4.2.2 Cleaning an assembl
36、ed system by flushing can deposit, or concentrate, contaminants in blind holes or recesses. Non-volatile cleaning agents may remain trapped and react later with oxygen. Cleaning solutions may degrade non-metallic materials inside assemblies or may cause corrosion of metallic items. 4.2.3 If construc
37、tion does not permit disassembly, it is essential to bleed all pressure from the system before starting any cleaning operations. Where there is the requirement for special procedures due to the possibility of an assembled system being significantly damaged by the cleaning process, it may be more pru
38、dent and economic to replace the system rather than to clean it. 4.3 Bought-in items 4.3.1 Bought-in items such as valves, regulators etc. should preferably be cleaned by the original manufacturer prior to assembly and test. They should be supplied suitably packaged to prevent re-contamination and l
39、abelled as oxygen-clean, see Clause 10. The purchaser should specify if certificates of cleanliness are to be supplied with these items, and should assess the suppliers cleaning processes and written procedures. 4.3.2 Where bought-in items have to be cleaned by the purchaser, they should, if possibl
40、e, be disassembled following the manufacturers instructions, inspected for damage, cleaned and tested for cleanliness, reassembled, and finally tested for correct functionality. 4.4 Cleaners 4.4.1 Two major cleaning process options are available for cleaning oxygen service equipment; aqueous based c
41、leaning methods with ultrasonic agitation, or solvent based systems which may involve wiping, brushing or vapour/ultrasonic cleaning. 4.4.2 Where necessary, prior to final cleaning to oxygen clean standards, a coarse cleaning process may be employed to remove gross contamination due to cutting fluid
42、s, swarf, burrs, fluxes, etc. 4.4.3 Mechanical cleaning methods such as abrasive blasting, tumbling, grinding and wire brushing are generally very aggressive and should be avoided on finished-machined items. They can damage sealing surfaces, remove or damage protective coatings, and work harden meta
43、l surfaces. 4.5 Selection of aqueous-based cleaning formulations 4.5.1 There are many proprietary aqueous cleaning formulations available that can be considered as being possibly suitable for cleaning oxygen service equipment. Ideally, an aqueous cleaning formulation should fulfil all of the followi
44、ng requirements: a) all areas of a component cleaned to a fully acceptable level; b) no significant corrosion or erosion of components; c) no non-oxygen compatible residues left on the surface of the components; d) environmentally friendly (low waste disposal costs) and non-toxic. 4.5.2 The cleaning
45、 efficacy of an aqueous-based cleaning solution will depend upon its composition. As much information as possible should be gained from the supplier of the cleaning solution concerning the nature and identity of the active ingredients. The basic ingredient of most aqueous-based cleaners is a primary
46、 detergent, usually an alkali such as sodium or potassium hydroxide. Where lower pH solutions are required because of potential corrosion problems, borax, sodium bicarbonate or sodium sesquicarbonate may be used to replace hydroxides as the basic builder ingredient. If aluminium alloy components are
47、 to be cleaned, it is preferable to use a solution with silicate as its primary ingredient. Silicates are less corrosive to aluminium alloys and will have an inhibiting effect on the action of more aggressive alkalis. Although phosphates have been widely used in aqueous based formulations in the pas
48、t, they are environmentally unfriendly and should not be used. Cleaners should be supplied in liquid concentrate form, since there is the possibility of particulate dispersion in the airspace when dissolving powder concentrates. This could have the consequence of contaminating components or creating
49、 a health hazard to personnel in the work area.BS 5N 100-7:2002 4 BSI 16 September 2002 4.5.3 Most aqueous-based cleaning solutions contain surfactants whose primary purpose is to reduce the surface tension. The lower the surface tension the easier it is for the solution to wet the surface and to penetrate into blind holes and crevices. Where components with complex geometry, blind holes or crevices etc. are to be cleaned, surface tension reducing surfactants
