BRITISH STANDARD AEROSPACE SERIES BS C 22 1995 ISO 9475 1994 Test methods for aircraft inner tube and tubeless tyre valves — Cores and caps Reproduced by IHS under l icense with BSI Uncontrol led Copy[.]
BRITISH STANDARD AEROSPACE SERIES Test methods for aircraft inner tube and tubeless tyre valves — Cores and caps Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy BS C 22:1995 ISO 9475:1994 BS C 22:1995 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee ACE/59, Aircraft tyres, rims and associated equipment, upon which the following bodies were represented: British Airways British Rubber Manufacturers’ Association Ltd Civil Aviation Authority (Airworthiness Division) Ministry of Defence Retread Manufacturers’ Association Society of British Aerospace Companies Ltd This British Standard, having been prepared under the direction of the Engineering Sector Board (E/- ) , was published under the authority of the Standards Board and comes into effect on April 995 © BSI 01 - 2000 The following BSI references relate to the work on this standard: Committee reference ACE/59 Draft for comment 93/71 01 05 DC ISBN 580 24046 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy Amendments issued since publication Amd No Date Comments BS C 22:1995 Contents Page Committees responsib le National foreword © BSI 01 - 000 ii Scope Normative references General Valve cores Tyre valve caps Figure — Manifold Table Table List of references Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy Inside front cover Inside back cover i BS C 22:1 995 National foreword This British Standard has been prepared by Technical Committee ACE/59 It is Aircraft inner tube and tubeless tyre valves — Cores and caps — Test methods, published by the International Organization identical with ISO 9475: 994, for Standardization (ISO) Cross-references International Standard ISO 81 5: 991 C orresponding British Standard Physical testing of rubber Method for determination of compression set at ambient, elevated or low temperatures BS 903 Part A6: 992 (Identical) ISO 868: 985 Methods of testing plastics Mechanical properties Method 365 B: 992 Determination of indentation hardness by means of a durometer (Shore hardness) BS 2782 Part The Technical Committee has reviewed the provisions of ISO 37: 994 and ISO 48: 994, to which normative reference is made in the text, and has decided that they are acceptable for use in conj unction with this standard 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 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 to 4, an inside back cover and a back cover This standard has been updated (see copyright date) and may have had amendments incorporated This will be indicated in the amendment table on the inside front cover ii Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy © BSI 01 - 2000 BS C 2 : 995 S cop e This International Standard specifies the test methods used for valve cores and caps for aircraft tyres, with or without inner tubes, and minimum airtightness standards It constitutes a detailed method allowing products to be evaluated on the same basis, and results to be compared Normative re fe re nce s The following standards contain provisions which, through reference in this text, constitute provisions f) environmental tests at constant high temperature (4 ) ; g) environmental tests at peak high temperature (4 ) Minimum airtightne ss re quire me nts Valve cores shall be rej ected if the leakage rate during tests is greater than 0, cm /min Ge ne ral te st conditio ns Unless otherwise specified, all tests shall be conducted under the following conditions: of this International Standard At the time of a) ambient temperature and pressure; publication, the editions indicated were valid All b) valve cores shall be installed in a six- position standards are subj ect to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below Members of IEC and ISO maintain registers of currently valid International Standards Rubber, vulcanized or thermoplastic — Determination of tensile stress-strain properties ISO 37: 994, Rubber, vulcanized or thermoplastic — Determination of hardness (hardness between 10 IRHD and 00 IRHD) ISO 48: 994, Rubber, vulcanized or thermoplastic — Determination of compression set at ambient, elevated or low temperatures ISO 81 5: 991 , Plastics and ebonite — Determination of indentation hardness by means of a durometer (Shore hardness) ISO 868: 985, manifold as shown in Figure ; c) tightening torques for cores with elastomeric valve seats shall be between 0, N·m and 0, 34 N·m; d) tightening torques for cores with metal (or elastomeric plus metal stop) valve seats shall be between 0, 34 N·m and 0, 54 N·m; e) the pressure inside the manifold shall be 800 kPa; f) airtightness shall be verified by immersing the core in water, acetone or alcohol Te st me thod s 4.4.1 Tightening torque test 4.4.1 Test conditions a) Carry out the test on six cores installed in a manifold in accordance with Figure b) Tighten the cores to the minimum torque Ge ne ral For the test methods, the requirements laid down under the test conditions are obligatory The procedure and certain additional performance requirements shall be fixed by agreement between the valve manufacturer and the client, with an obligation to meet the minimum airtightness requirements defined in this International Standard specified in 4.3 c) The test pressure is 200 kPa to 800 kPa 4.4.1 Performance requirement The core leak- rate shall not be greater than the value set in 4.2 throughout the pressure range Checks shall be made at least at the minimum and maximum pressures 4.4.2 Washout test This test simulates rapid deflation at high pressure Valve core s 4.4.2.1 Test conditions Typ e s o f te sts a) Carry out this test on cores which have Aircraft tyre valve cores shall be submitted to the successfully passed the tightening torque following tests: a) tightening torque test (4 ); b) washout test (4 ); c) blowout test (4 ); d) pressurized pulse test (4 ) ; e) environmental tests at low temperature (4 ); © BSI 01 - 2000 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy test (4 ) b) Set the manifold pressure to 800 kPa c) Carry out test cycles, defined as follows, on each valve core: ) open each core manually and keep it open for at least s to allow the pressurized air to escape at high speed across the valve seal; 2) allow the core to close freely BS C 2 : 995 Figure — Manifold 4.4.2.2 Performance requirement b) Carry out the pulse tests on the valve cores in The leak- rate, measured after cycles, shall not be greater than the value specified in 4.4.3 Blowout test 4.2 4.4.4.2 Performance requirement Throughout the test, the leak- rate shall not be This test simulates rapid inflation at high pressure 4.4.3.1 accordance with Table Test conditions greater than the value set in 4.4.5 a) Carry out this test on the cores that have passed the tightening torque test (4 ) and the 4.2 It shall be noted after every 000 cycles Environmental test at low temperature 4.4.5.1 Test conditions washout test (4 ) a) Carry out this test on six new cores installed in b) Carry out test cycles, defined as follows, on a test manifold in accordance with Figure each valve core: b) Hold the cores at a temperature of – 54 ° C ) reduce the manifold pressure to kPa; for 24 h 2) attach a standard connector to a 800 kPa c) Check the airtightness in acetone or alcohol compressed air system; 3) keep each core open for at least s to allow the pressurized external air to enter the d) After cooling, check the airtightness at each of manifold at high speed across the valve seal; the following stages, in the order indicated: 4) after s, remove the inflation connector and ) at 800 kPa; if the core leaks, retighten to let the core close freely the maximum torque defined in 4.4.3.2 Performance requirement Pressurized pulse test 4.4.4.1 4.2 Test conditions a) Carry out this test on six new cores installed in a manifold in accordance with Figure Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy 4.3; 2) washout test (4 ) ; The leak- rate, measured after cycles, shall not be greater than the value specified in 4.4.4 cooled to – 54 ° C, with air cooled to – 54 ° C at a pressure of 800 kPa 3) blowout test ( ); 4) at 200 kPa; 5) at 620 kPa; 6) at 380 kPa; 7) at 800 kPa Perform seven test cycles at each pressure © BSI 01 - 2000 BS C 2 : 995 Tab le Pre ssu re O p e rati o n kPa a High-pressure cycle 380 Normal cycle 620 Low-pressure cycle 200 max 800 380 620 C ycle s p e r mi nute co nd i ti o n 35 35 a Never let the pressure fall below the indicated minimum pressures 4.4.5.2 Performance requirement To tal cycle in this 000 000 000 c) ageing test ( ); d) screwing/unscrewing test ( 5.3.3 ) Under each test condition, the leak-rate shall not be greater than the value set in Environmental test at constant high No leakage is acceptable during the various temperature airtightness checks Leaking caps shall be rejected 5.3.4 4.2 Minimum airtightne ss re quire me nt 4.4.6 4.4.6.1 Test conditions Te st me thod s a) Carry out this test on the same cores as passed Mechanical properties of gasket the low-temperature test ( ) materials b) Place them in an oven and increase the Test conditions temperature to + 93 °C Hold this for 24 h a) Determine the following initial properties of c) Cool the samples to + 52 °C and check the the gasket material as indicated: airtightness in water at + 52 °C with air — breaking strength, in accordance with at + 52 °C at a pressure of 800 kPa ISO 37; d) Then follow the test procedure in d) — elongation in accordance with ISO 37; Performance requirement — hardness in accordance with ISO 48 or Under each test condition, the leak-rate shall not be ISO 868; greater than the value set in — compression set in accordance with Environmental test at peak temperature ISO 815 Test conditions b) Determine the properties of the seal again after oven-ageing at + 93 °C for days a) Carry out this test on the same cores as passed the low-temperature test ( ) and constant Performance requirements high-temperature test ( ) Variations in tensile strength, elongation and b) Place them in an oven and increase the hardness characteristics determined after temperature to + 120 °C Hold this for 20 oven-heating shall not differ from initial characteristics by more than the maximum c) Cool the samples to + 52 °C and check the variation values given in Table airtightness in water at + 52 °C with air at + 52 °C at a pressure of 800 kPa d) Then follow the test procedure in d), 10 times max max Performance requirement Tensile strength — 20 % Under each test condition, the leak-rate shall not be Elongation — 30 % or 40 % greater than the value set in (to be specified) Shore A hardness 10 % — Temperature resistance test Test conditions Aircraft tyre valve caps shall be submitted to the following tests: a) Carry out this test on six valve caps a) determination of mechanical properties of seal b) The service temperature range is – 54 °C material ( ); to + 93 °C with a 24-h holding period at each of these two temperatures b) temperature resistance test ( ); 5.3.1 4.4.5 5.3.1 4.4.5.1 4.4.6.2 4.2 4.4.7 4.4.7.1 4.4.5 5.3.1 4.4.6 Tab le Incre ase D e cre ase C haracte ristic 4.4.5 4.4.7.2 4.2 Tyre valve cap s 5.3.2 Te st typ e s 5.3.2.1 5.3.1 5.3.2 © BSI 01-2000 Reprodu ced by I H S u n d er l i cen se wi th BSI - U n trol l ed Copy BS C 2 : 995 c) The cap tightening torque is b etween 0, 56 N·m Carry out at least five of the and 0, 79 N·m screwing/unscrewing cycles at – 54 d) The test pressure is up to 800 kPa 5.3.2.2 Performance requirements The requirement in shall be met within the temperature and torque tightening range for pressures of up to 800 kPa 5.3.3 Ageing test Test conditions minimum of 72 h The caps shall not b e screwed onto the valve body during this 72 - h hold period at – 54 °C c) Screw the caps which have undergone screwing/unscrewing cycles b ack onto the valve body and torque them to between 0, 56 N·m a) Carry out this test on six valve caps b) Place the caps in an oven and increase the 5.3.3.2 on caps and 0, 79 N·m 5.3.3.1 temperature to + 93 °C which have b een held at this temperature for a ° C Hold this for days Performance requirements d) Apply a pressure of 70 kPa and hold it for h e) Apply a pressure of 800 kPa and hold it for h f) With the caps still tightened onto the valve body with the same torque, cool them to – °C After oven heating, the requirement in shall be and hold this temperature for h, applying an met internal pressure to the cap of at least 800 kPa 5.3.4 Screwing unscrewing test Test conditions / 5.3.4.1 a) Carry out this test on three new caps and three caps aged in accordance with b) Screw the caps down with a torque 5.3.4.2 Performance requirements The requirement in shall be met during stages d) , e) and f) In addition, after this test, the seal shall rotate freely within the cap without becoming unseated of 0, 56 N·m times, unscrewing them each time, ensuring that the seals break contact with the valve mouth Reprodu ced by I H S u n d er l i cen se wi th BSI - 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