BS 4N 100-2:1999:2005 Edition
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Aircraft oxygen systems and equipment. Tests for the compatibility of materials in the presence of oxygen
Published By | Publication Date | Number of Pages |
BSI | 2005 | 24 |
PDF Catalog
PDF Pages | PDF Title |
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1 | BRITISH STANDARD AEROSPACE SERIES |
2 | Committees responsible for this British Standard |
3 | Contents |
5 | 1 Scope 2 Normative references 3 Definitions non-metallic materials spontaneous ignition temperature (SIT) specific spontaneous ignition temperature statistically defined spontaneous ignition temperature heat of combustion critical oxygen index |
6 | 4 General 4.1 Introduction 4.2 The pot test 4.3 The bomb test |
7 | Determination of maximum working pressure 4.4 Liquid oxygen impact test |
8 | Detail of striker pin |
10 | Liquid oxygen impact machine |
11 | 5 New bomb test criteria 5.1 The bomb shall be operable in a range of pressures up to a maximum of 69 MPa. 5.2 The bomb shall be capable of maintaining a constant pressure environment. 5.3 The test volume of the bomb shall attain a maximum temperature of 823 K (550 °C). 5.4 The bomb shall enable composite and hybrid materials to be tested. 5.5 The bomb shall be located in a safe environment, within for example, a high pressure containment system. 5.6 The bomb’s constructional materials shall be selected from oxygen safe materials which should be in accordance with BS N 100-6. 5.7 Potential ignition sources shall be eliminated. (See BS N 100-5 for guidance.) 5.8 There shall be access to allow for the routine maintenance and regular cleaning of vessel, pipelines and connected components. Cleanliness is of utmost importance and guidance should be sought from BS N 100-7. 5.9 The bomb shall enable loading of samples and repeatable placement of the combustion boat with respect to thermocouple installations. 5.10 The bomb shall contain more than one thermocouple to improve the reliability and reproducibility of detecting the onset of ignition. 5.11 The instrumentation used to monitor the operating pressure shall have a sensitivity within ±0.1 MPa. 5.12 Provision shall also be made for the use of a sensitive data acquisition and evaluation computer programme, to provide the …7.1. 5.13 The measured ignition temperature shall be a function of the material and its volatile components, rather than a function of the experimental apparatus and the pre-selected values of its adjustable operational parameters, e.g. heating rate. |
12 | New bomb test containment vessel assembly |
13 | New bomb test combustion vessel |
14 | 6 New bomb test 6.1 Design of suitable test apparatus 6.2 Components of the system |
15 | 6.3 Sample preparation 6.4 Operation of apparatus |
16 | System diagram |
19 | 6.5 Typical results Specific SIT of a common fluoroelastomer at an oxygen pressure of 13.2 MPa |
20 | Typical temperature versus time plot for a common fluoroelastomer |
21 | 7 Treatment of results from the new bomb test 7.1 The statistically defined SIT (3.4) for each test sequence shall be determined by calculating the arithmetic mean and the standard root mean square deviation of a minimum of six ignition temperatures. 7.2 If any result deviates by more than 10 K from the arithmetic mean of the six results, the results shall be discarded. The particular sample preparation (see 6.3) and operation of apparatus (see 6.4) used to determine the results shall be reviewed fo 7.3 An oxygen pressure of 13.2 MPa shall be used for comparison between new and old test data, and hence the criteria for selection of materials is maintained. 7.4 The statistically defined SIT for 13.2 MPa shall be calculated in accordance with 7.2 and Table 3 shall be used to obtain the maximum working pressure for temperatures up to 363 K (90 °C). Maximum working pressures for different categories of materials |
22 | (normative) (normative) Form 1 |