PD CLC/TR 50451:2007
Superseded
A superseded Standard is one, which is fully replaced by another Standard, which is a new edition of the same Standard.
View Superseded by
Railway applications. Systematic allocation of safety integrity requirements
Hardcopy , PDF
30-11-2018
English
31-12-2010
Important note : Users cannot be edited or removed once added to your Multi user PDF.
Executive summary
Introduction
1 Scope
2 References
2.1 Normative references
2.2 Informative references
3 Definitions
4 Symbols and abbreviations
5 Safety Integrity Levels allocation framework
5.1 Prerequisites
5.2 Overview of the methodology
5.3 Definition of Safety Integrity Levels
5.4 Qualitative vs quantitative methods
5.4.1 Qualitative assessment
5.4.2 Quantitative assessment
5.5 EN 50126-1 lifecycle context
6 System definition
7 Hazard identification
7.1 General principles
7.2 Empirical hazard identification methods
7.3 Creative hazard identification methods
7.4 Hazard
7.5 Existing hazard lists
8 Risk analysis
8.1 Risk tolerability
8.2 Determination of Tolerable Hazard Rate
8.2.1 Qualitative risk analysis
8.2.2 Quantitative risk analysis
8.2.3 GAMAB and similar approaches
8.2.4 The MEM approach
8.2.5 Other approaches
9 System design analysis
9.1 Apportionment of safety integrity requirements
to functions
9.1.1 Physical independence
9.1.2 Functional independence
9.1.3 Process independence
9.2 Use of SIL tables
9.3 Identification and treatment of new hazards
arising from design
9.4 Determination of function and subsystem SIL
9.5 Determination of safety integrity requirements
for system elements
Annex A - Single-line signalling system example
Annex B - Level crossing example
Annex C - Comparison of demand and continuous mode
Annex D - Frequently asked questions
Describes a method to determine the required Safety Integrity Level of railway signalling equipment taking in consideration the operational conditions of the railway, and the architecture of the signalling system.
| Committee |
GEL/9/1
|
| DevelopmentNote |
Supersedes BS PD R009-004. (06/2007)
|
| DocumentType |
Standard
|
| Pages |
90
|
| PublisherName |
British Standards Institution
|
| Status |
Superseded
|
| SupersededBy | |
| Supersedes |
The scope of this Technical Report is to define a method to determine the required Safety Integrity Level of railway signalling equipment taking in consideration
the operational conditions of the railway, and
the architecture of the signalling system.
The following picture may be used in order to detail more precisely the scope of this Technical Report:
From a mechanistic point of view the task of this Technical Report is to define a method of calculation, which determines the integrity requirements (qualitatively and quantitatively) from the inputs stated above.
| Standards | Relationship |
| CLC/TR 50451:2007 | Identical |
| ISO/IEC 15026:1998 | Information technology System and software integrity levels |
| R009-001 : 1997 | RAILWAY APPLICATIONS COMMUNICATION, SIGNALLING AND PROCESSING SYSTEMS HAZARDOUS FAILURE RATES AND SAFETY INTEGRITY LEVELS (SIL) |
| EN 50128:2011/AC:2014 | RAILWAY APPLICATIONS - COMMUNICATION, SIGNALLING AND PROCESSING SYSTEMS - SOFTWARE FOR RAILWAY CONTROL AND PROTECTION SYSTEMS |
| EN 50129 : 2003 COR 2010 | RAILWAY APPLICATIONS - COMMUNICATION, SIGNALLING AND PROCESSING SYSTEMS - SAFETY RELATED ELECTRONIC SYSTEMS FOR SIGNALLING |
| EN 50126-1:2017 | Railway Applications - The Specification and Demonstration of Reliability, Availability, Maintainability and Safety (RAMS) - Part 1: Generic RAMS Process |
| EN 50121-5:2017 | Railway applications - Electromagnetic compatibility - Part 5: Emission and immunity of fixed power supply installations and apparatus |
| DEFSTAN 00-56/1(1991) : 1991 | HAZARD ANALYSIS AND SAFETY CLASSIFICATION OF THE COMPUTER AND PROGRAMMABLE ELECTRONIC SYSTEM ELEMENTS OF DEFENCE EQUIPMENT |
Access your standards online with a subscription
Features
-
Simple online access to standards, technical information and regulations.
-
Critical updates of standards and customisable alerts and notifications.
-
Multi-user online standards collection: secure, flexible and cost effective.