Overview
IEC TR 63176:2019 - "Process analysis technology systems as part of safety instrumented systems" - is a technical report from the IEC that provides recommendations for the planning, installation, qualification and operation (including maintenance) of process analyzer technology (PAT) when used as components of Safety Instrumented Systems (SIS) in the process industry. The document focuses on practical guidance to supplement SIS safety management by adding special requirements for analyzer measuring equipment. It clarifies that “qualification” here means testing the suitability of PAT for SIS use (not pharmaceutical qualification).
Key topics and technical requirements
IEC TR 63176:2019 addresses the lifecycle aspects and specific technical considerations of PAT within SIS, including:
- Qualification process - structured steps and documentation required to verify PAT suitability for safety functions.
- Constructor and plant operator responsibilities - roles and recommended requirements for suppliers and end-users.
- Basic testing of analysers - on-site and factory test considerations tailored to analyzers in SIS applications.
- Engineering and design data - analyser application, sample conditioning, sample switching and safety logic integration.
- Reliability and safety assessment methods - Failure Mode, Effects and Diagnostic Analysis (FMEDA) and Probability of Failure on Demand (PFD) estimation approaches.
- Hardware Fault Tolerance (HFT) considerations and how they relate to SIL achievement.
- Periodic testing and maintenance - commissioning, periodic inspections, fault logging, handling deviations, modifications, decommissioning and recommissioning.
- Documentation - compilation of qualification evidence, maintenance schedules, working instructions and records.
- Grandfathering and proven performance - guidance for existing installations and in-service performance evidence.
Practical applications and who uses this standard
IEC TR 63176 is intended for professionals involved in implementing PAT within SIS, such as:
- Process safety engineers and functional safety managers
- Instrumentation and control engineers
- Plant operators and maintenance teams
- Analyser and system manufacturers, and system integrators
- Asset integrity and reliability engineers
- Certification and conformity assessment bodies (for guidance)
Typical applications include using gas and liquid analysers as safety sensors, integrating sample conditioning and switching hardware into safety loops, performing FMEDA/PFD analyses for analyzer-based SIS channels, and defining maintenance/periodic testing plans to meet safety performance targets.
Practical value / Benefits
- Helps achieve equivalent safety when normative requirements for analysers are insufficient or incomplete.
- Reduces risk of systematic and random failures through structured qualification, testing and maintenance.
- Provides a clear lifecycle approach for incorporating PAT into SIS and documenting safety evidence.
Related standards
IEC TR 63176 references and complements these key functional safety and EMC standards:
- IEC 61508 (all parts) - Functional safety of electrical/electronic/programmable electronic safety-related systems
- IEC 61511 (all parts) - Safety instrumented systems for the process industry sector
- IEC 61326-3-1 and IEC 61326-3-2 - EMC immunity requirements for safety-related measurement and control equipment
Keywords: IEC TR 63176:2019, process analysis technology, PAT, safety instrumented systems, SIS, analyser qualification, FMEDA, PFD, periodic testing, IEC 61511, IEC 61508.