1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD AEROSPACE SERIES BS 3N 3:
2、2000 (superseding BS 2N 3 : 1990) NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Breathing oxygen for airborne applicationsThis British Standard, having been prepared under the direction of the Advanced Manufacturing Technology Assembly, was published under the authority of t
3、he Standards Committee and comes into effect on 15 March 2000 BSI 03-2000 The following BSI references relate to the work on this standard: Committee reference ACE/38 Draft for comment 99/705176 DC ISBN 0 580 33067 2 BS 3N 3:2000 Amendments issued since publication Amd. No. Date Comments Committees
4、responsible for 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 (Airworthiness Divisi
5、on) Health and Safety Executive Ministry of Defence Society of British Aerospace Companies Ltd. South Bank UniversityBS 3N 3:2000 BSI 03-2000 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Gaseous breathing oxygen 1 4 Liquid oxygen (LOX) 2 Bibliogra
6、phy Inside back cover Table 1 Maximum concentration of contaminants in gaseous breathing oxygen 1 Table 2 Maximum concentration of contaminants in gasified LOX 2ii BSI 03-2000 BS 3N 3:2000 Foreword This British Standard has been prepared by Technical Committee ACE/38. It supersedes BS 2N 3:1990 whic
7、h is withdrawn. This revision introduces requirements for liquid oxygen in addition to gaseous oxygen and is based largely on Def Stan 16-1/3 (16 October 1992) 1. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for
8、 their correct 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 and ii, pages 1 and 2, an inside back cover and a back cover. The BSI copyright notice disp
9、layed in this document indicates when the document was last issued. BSI 03-2000 1 BS 3N 3:2000 1 Scope This British Standard specifies the characteristics of liquid and gaseous oxygen supplied for the replenishment of airborne oxygen systems. 2 Definitions 2.1 liquid oxygen (LOX) pale blue liquid wi
10、th a temperature of approximately 21838C at 101.3 kPa (760 mm Hg) ambient pressure and having a density of 1.14 kg/l 2.2 normal temperature and pressure (NTP) ambient temperature of 158C and atmospheric pressure of 101.3 kPa (760 mm Hg) 2.3 gasification, gasify process of producing gaseous oxygen, f
11、or analysis, from a LOX sample without atmospheric contamination 3 Gaseous breathing oxygen 3.1 Production The gas shall be evaporated from liquid oxygen produced by the fractional distillation of liquid air. 3.2 Odour The oxygen shall be odourless (see 4.2.3 for method of test for liquid oxygen). 3
12、.3 Purity The minimum purity of oxygen delivered to the system shall be 99.5 % by volume. NOTE Gases supplied for breathing should not contain any contaminants, whether specified in this document or not, at a concentration which is likely to cause toxic or harmful effects to the user. The limit of c
13、oncentration for any contaminant should be derived from the occupational exposure levels (OEL) set by the HSE 2, taking into account the effects of pressure and exposure time. 3.4 Water content The water content of the oxygen shall not exceed 5 mgm 23 calculated at NTP. This corresponds to a dew poi
14、nt of263.38Ca ta n ambient pressure of 101.3 kPa (760 mm Hg) which is equivalent to a saturation temperature of240.08C (or lower) at a pressure of 2.1 MPa. 3.5 Contaminants 3.5.1 The maximum concentration of contaminants shall conform to those specified in Table 1. Nitrogen and inert gases shall not
15、 be considered to be contaminants. There shall be no oil, mist or aerosol. 3.5.2 If the presence of contaminants other than those in Table 1 are detected, this shall be reported. If any such contaminant can be identified, its concentration shall not exceed 0.1 ppm (by volume) except where the note t
16、o 3.3 applies. Table 1 Maximum concentration of contaminants in gaseous breathing oxygen Constituent Maximum concentration, ppm (by volume) Carbon dioxide 10.0 Carbon monoxide 1.0 Methane 50.0 Acetylene 0.05 Ethylene 0.2 Ethane and higher hydrocarbons 3.0 (ethane equivalent) Nitrous oxide 2.0 Refrig
17、erants 1.0 Solvents 0.1 Other (see 3.5.2) 3.6 Solids content The oxygen shall contain no particles with any dimension longer than 100mm. The total mass of solids shall not exceed 1 mgm 23 of gaseous oxygen at NTP. 3.7 Marking Cylinders and other containers filled with gaseous oxygen conforming to th
18、is British Standard shall be clearly marked as follows: “Aviators breathing oxygen”; or “O 2 AV”.2 BSI 03-2000 BS 3N 3:2000 4 Liquid oxygen (LOX) 4.1 Sampling NOTE 1 Samples of LOX may be taken at any time from the production plant or any portion of a consignment. If any sample from the production p
19、lant is found not to conform to the requirements of this British Standard, all deliveries may be rejected, including those in transit. If any sample from a consignment is found not to conform to this British Standard, the whole consignment may be rejected. NOTE 2 Due to the cryogenic nature of LOX,
20、special precautions should be observed. Particular attention should be paid to the following: a) wear protective equipment, including face and eye shields; b) protect connecting hoses from moisture and other contaminants when not in use; c) ensure the sample container, associated hoses and pipes are
21、 thoroughly clean and dry before use by heating and/or purging with warm, dry, oil-free nitrogen or oxygen; d) always flush the hoses, pipes and containers with LOX then discard any LOX collected before taking the sample for analysis. 4.2 Purity 4.2.1 When examined in a clear Dewar flask, the LOX sa
22、mple shall be free from any suspended matter and visible impurities. 4.2.2 After gasification, the minimum purity of oxygen shall be 99.5 % by volume. 4.2.3 The method of test for odour shall be as follows. Pour approximately 100 ml of the LOX into a clean 400 ml beaker, rotate it gently to cool the
23、 beaker and pour off the LOX. Cover the bottom of the beaker with a piece of filter paper and add 200 ml of the LOX, then cover the beaker with a watch glass to prevent atmospheric constituents being absorbed by the LOX. Allow the LOX to evaporate to dryness in a volume free from air currents and ex
24、traneous odours. Remove the watch glass and check the odour of the beaker contents at regular intervals until all the frost on the outside of the beaker has melted (any odour will be most noticeable when the beaker has warmed nearly to room temperature). When tested in accordance with this test no o
25、dour shall be detected (see 3.2). 4.3 Water content When gasified, the water content of the oxygen shall conform to 3.4. Any saturation temperature apparatus used to measure water content shall have a reproducibility of 18Ca t2 40.08C. 4.4 Contaminants 4.4.1 After gasification of the LOX sample, the
26、 maximum concentration of contaminants shall conform to those specified in Table 2. Nitrogen and inert gases shall not be considered to be contaminants. 4.4.2 If the presence of contaminants other than those specified in Table 2 are detected, this shall be reported. If any such contaminant can be id
27、entified, its concentration shall not exceed 0.1 ppm (by volume) except where the note of 3.3 applies. Table 2 Maximum concentration of contaminants in gasified LOX Constituent Maximum concentration, ppm (by volume) Carbon dioxide 5.0 Methane 50.0 Acetylene 0.05 Ethylene 0.2 Ethane and higher hydroc
28、arbons 3.0 (ethane equivalent) Nitrous oxide 2.0 Refrigerants 1.0 Solvents 0.1 Other (see 4.4.2) BSI 03-2000 BS 3N 3:2000 Bibliography Other documents 1 Def Stan 16-1/Issue 3: 1992 Oxygen; Liquid and gaseous (breathing) for aircraft systems. 2 HSE Guidance Note EH40, Health and Safety Executive, HSE
29、 Books, PO Box 1999, Sudbury, Suffolk, CO10 2WA.BS 3N 3:2000 BSI 389 Chiswick High Road London W4 4AL | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
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