Concat us[email protected]
Shopping Cart

No products in the cart.

🔍
BS EN IEC 61124:2023

BS EN IEC 61124:2023

$215.11

Reliability testing. Compliance tests for constant failure rate and constant failure intensity

Published By Publication Date Number of Pages
BSI 2023 96
PDF Format Searchable Printable Preview Now
Guaranteed Safe Checkout
Category:

If you have any questions, feel free to reach out to our online customer service team by clicking on the bottom right corner. We’re here to assist you 24/7.
Email:[email protected]

This International Standard gives a number of optimized test plans, the corresponding border lines and characteristics. In addition the algorithms for designing test plans using a spreadsheet program are also given, together with guidance on how to choose test plans. This standard specifies procedures to test whether an observed value of – failure rate, – failure intensity, – mean operating time to failure (MTTF), – mean operating time between failures (MTBF), conforms to a given requirement. It is assumed, except where otherwise stated, that during the accumulated test time, the times to failure or the operating times between failures are independent and identically exponentially distributed. This assumption implies that the failure rate or failure intensity is assumed to be constant. Four types of test plans are described as follows: – truncated sequential probability ratio test (SPRT); – fixed time/failure terminated test (FTFT); – fixed calendar time terminated test without replacement; – combined test. This standard does not cover guidance on how to plan, perform, analyse and report a test. This information can be found in IEC 60300-3-5. This standard does not describe test conditions. This information can be found in IEC 60605-2 and in IEC 60300-3-5.

PDF Catalog

PDF Pages PDF Title
2 undefined
5 Annex ZA (normative)Normative references to international publicationswith their corresponding European publications
6 Blank Page
7 English
CONTENTS
11 FOREWORD
13 INTRODUCTION
15 1 Scope
2 Normative references
16 3 Terms, definitions, abbreviated terms and symbols
3.1 Terms and definitions
3.2 Abbreviated terms and symbols
3.2.1 Abbreviated terms
3.2.2 Symbols
18 4 General requirements and area of application
4.1 Requirements and characteristics
4.2 Applicability to replaced and repaired items
19 4.3 Types of test plans
4.3.1 General
4.3.2 Advantages and disadvantages of the different test plan types
20 Tables
Table 1 – Advantages and disadvantages for the different test plan types
21 5 General test procedure
5.1 Test conditions
Figures
Figure 1 – Relative ETT (Te*/m0) and MaxTT (Tt*/m0) of various tests with the same risks
22 5.2 General characteristics of the test plans
5.3 Data to be recorded
5.4 Calculation of accumulated test time, T*
23 5.5 Number of failures
6 Truncated sequential probability ratio test (SPRT) plans
6.1 General
24 6.2 Common test procedure
6.3 Decision criteria
25 6.4 Operating characteristic (OC) curve
Figure 2 – SPRT diagram and test example
Table 2 – OC curve
26 6.5 Expected accumulated test time to decision (ETT)
Figure 3 – OC curve, Pa
Table 3 – Relative ETT versus m/m0
27 6.6 Overview of test plans
Figure 4 – SPRT – Curve of expected accumulated test time to decision (ETT)
28 Table 4 – Overview of type A SPRT plans
30 7 Fixed time/failure terminated test plans – Fixed duration (to acceptance) test plans
7.1 General
Table 5 – Overview of type C SPRT plans
31 7.2 Common test procedure
7.3 Decision criteria
7.4 Test plans
32 8 Design of alternative time/failure terminated test plans (FTFT)
8.1 General
8.2 Design procedures
Table 6 – Type B FTFT plans
33 8.3 Common FTFT procedure
8.4 Decision criteria
9 Calendar time/failure terminated test plans (FTFT) for non-replaced items
9.1 General
34 9.2 Common test procedure
9.3 Decision criteria
9.4 Use of IEC 61123:2019, Table 5 for fixed calendar time tests
9.4.1 General
35 9.4.2 Procedure when the test time is given
9.4.3 Procedure when the number of items is given
10 Combined test plans
10.1 General
10.2 Common test procedure
36 10.3 Decision criteria
10.4 Test plans
Figure 5 – Example of a decision graph for combinedtest plan (type D) and for SPRT type C
37 11 Performing the test and presenting the results
Table 7 – Overview of type D combined plans
38 Annex A (normative)Tables for border lines of SPRT plans (types A and C)
A.1 Symbols
A.2 Border lines
39 Figure A.1 – Decision graph of SPRT plan
40 Table A.1 – Constants for border line formulae and their coordinatesfor type A SPRT plans
41 Table A.2 – Constants for border line formulae and their coordinatesfor type C SPRT plans
42 A.3 Example of the SPRT plan from Clause 6
43 Table A.3 – Example for SPRT using test plan A.41 (with example data)
44 Annex B (normative)Tables and graphs for combined test plans (type D)
B.1 General
Table B.1 – Combined test plans in ‎Annex B
45 Table B.2 – Type D test plans – Accept and reject lines
46 B.2 Test plans D.3 and C.3 (α = β = 10 %, D = 1,7)
Table B.3 – Expected accumulated test time to acceptance decision,Te*(+), for D and C test plans
47 Table B.4 – Accept and reject lines for D.3 and C.3 test plans
48 Figure B.1 – Expected accumulated test time to acceptance decision,Te*(+) for D.3 and C.3 test plans
Figure B.2 – Operating characteristic Pa for D.3 and C.3 test plans
49 Annex C (informative)Extension of the set of SPRTs type A
C.1 Symbols
C.2 Extension of the set of type A tests (through interpolation by α and β )
51 Table C.1 – Example for interpolation by α and β
52 Annex D (informative)Approximation of operating characteristic fortype A SPRTs by Wald’s formula
D.1 Symbols
D.2 Approximations of OC in this document
D.3 Approximation of OC for type A SPRT by Wald’s formula
53 Figure D.1 – Approximation of OC for type A SPRT using Wald’s formula
54 D.4 Construction of the approximated OC curve using a spreadsheet
55 Table D.1 – Spreadsheet set-up for construction of the OC curve by Wald
Table D.2 – Formulae embedded in the spreadsheet
56 Annex E (informative)Mathematical references and examples forfixed time/failure terminated test (FTFT) plans
E.1 Symbols
E.2 Mathematical references
E.2.1 General
E.2.2 Mathematical references
59 E.2.3 Design procedure {a}
Table E.1 – List of the typical FTFT design procedures
60 E.2.4 Design procedure {b}
E.2.5 Design procedure {c}
61 E.2.6 Design procedure {d}
E.3 Examples of FTFT design using test plans B
E.3.1 Example 1
62 E.3.2 Example 2
Figure E.1 – Example 1 – Expected accumulated test timeto decision (ETT) of tests B.2 and A.25
63 E.4 Test OC approximation using formula for FTFT
Figure E.2 – Example 1 – Operating characteristic of tests B.2 and A.25
64 Annex F (informative)Examples of FTFT design using a spreadsheet program
F.1 General
65 Table F.1 – Set-up of the spreadsheet with embedded formulae
66 F.2 Finding the test border lines using optimization on the example of the design procedure {b}
Table F.2 – Formulae embedded in the spreadsheet
67 Table F.3 – Fragment from Table 6
68 F.3 ETT and OC curves
Figure F.1 – Using Solver to find Tt*/m0 –Accumulated test truncation time in terms of m0
69 Figure F.2 – ETT plotted from the spreadsheet calculations
Figure F.3 – OC curve plotted from the spreadsheet calculations
70 F.4 Example of FTFT design by procedure {a}
Table F.4 – Set-up 1 of the spreadsheet for example by procedure {a}
71 Figure F.4 – Using Solver to find Tt*/m0 and c in Step {a1}
Table F.5 – Set-up 2 of the spreadsheet for example by procedure {a}
72 F.5 Example of FTFT design by procedure {c}
Figure F.5 – Using Solver to find Tt*/m0 in Step {a2}
Table F.6 – Set-up 3 (final solution) for example by procedure {a}
73 Table F.7 – Set-up 2 for example by procedure {c}
74 F.6 Example of FTFT design by procedure {d}
Figure F.6 – Using Solver to find Tt*/m0 in Step {c2}
Table F.8 – Set-up 3 (final solution) for example by procedure {c}
75 Table F.9 – Set-up 1 of the spreadsheet for example by procedure {d}
76 Figure F.7 – Using Solver to find D and c in Step {d1}
Table F.10 – Set-up 2 of the spreadsheet for example by procedure {d}
77 F.7 Example of a test with replacement of failed items
Figure F.8 – Using Solver to find D and Tt* in Step {d2}
Table F.11 – Set-up 3 (final solution) for example by procedure {d}
78 F.8 Evaluation of an approximate OC for non-FTFT plans using a spreadsheet
79 Table F.12 – Set-up of the spreadsheet with embedded formulae from Clause F.8
80 Figure F.9 – Using Solver to find c and Tt*/m0 from Clause F.8
Table F.13 – Set-up 1 of the spreadsheet from Clause F.8
81 Table F.14 – Set-up 2 of the spreadsheet for example from Clause F.8
82 Figure F.10 – OC approximated by formula for FTFT (example from Clause F.8)
83 Annex G (informative)Examples and mathematical references forthe calendar time terminated test plans
G.1 Examples
G.1.1 Example 1
G.1.2 Example 2
84 G.2 Mathematical background
85 Annex H (informative)Derivation and mathematical reference for the optimized test plansof GOST R 27 402 [12]
H.1 Symbols
86 H.2 Test plan types and terminology
H.3 Introductory remarks
Figure H.1 – Test plan types and terminology
87 H.4 Procedure used for developing the optimized test plans
88 Figure H.2 – Principle of test plans
Figure H.3 – Partitioning of the test plan graph
Figure H.4 – Interior nodes and border nodes
89 Figure H.5 – Paths to the accept line
Figure H.6 – Paths to the reject line
90 Figure H.7 – Probabilities of paths transfer between nodes
93 Figure H.8 – Recurrent element – Two cases
94 Bibliography

Related products

BS EN IEC 61124:2023
$215.11