Understanding Functional Safety
The risks from process-related hazards can be managed in a number of ways. The intrinsic risks can be reduced by minimising inventories of hazardous materials; process control systems can be implemented; process alarms provided; and mechanical equipment such as pressure relief devices can be implemented to limit the consequences of upsets. For some hazards, these measures need to be supplemented by a ‘functional safety’ system that detects when the process is outside its safe operating envelope, and takes an automatic executive action to maintain a safe state.
Functional safety systems have complex requirements, and need meticulous planning to ensure they achieve their risk reduction objective throughout the project life. xSeriCon has the knowhow and experience to support your functional safety management from project inception to final decommissioning, in compliance with international standards IEC 61508, 61511 and 62061.
FUNCTIONAL SAFETY MANAGEMENT PLAN
A requirement of functional safety standards such as IEC 61508 and IEC 61511 is to
develop and implement a functional safety life cycle. This is normally defined in a
Functional Safety Management Plan (FSMP), indicating the procedure, inputs and
outputs for each life cycle phase.
The FSMP also describes the approach to other aspects of functional safety
management, including:
- Planning
- Roles and responsibilities
- Competency assurance
- Management of contractors
- Tasks designed to ensure the Safety Instrumented System (SIS) is effective and to
minimize human errors, such as verification, SIS validation, Functional Safety
Assessment, and Functional Safety Audit - Management of change
- Configuration management
- Operations and maintenance strategy
xSeriCon is highly experienced at all aspects of Functional Safety Management. Our
team are ready to support you in the development of an FSMP for your project.
SAFETY REQUIREMENTS SPECIFICATION
The Safety Requirements Specification (SRS) is the heart of the Functional Safety
Life Cycle. It is intended as a repository of information that guides the team in all
subsequent life cycle phases, including:
- SIS design
- Application Program development
- Factory Acceptance Test (FAT)
- SIS Validation
- SIS performance evaluation during the operational phase
- Management of Change
xSeriCon’s depth of experience in Functional Safety can support your project in
efficiently developing a useful and accurate SRS, or reviewing and verifying the SRS
prepared by others.
FUNCTIONAL SAFETY ASSESSMENT
This is a high level review intended to demonstrate that the Functional Safety
Management Plan is achieving its objective—namely, to yield a standards-compliant
Safety Instrumented System that is essentially free from human errors that can
cause systematic failures. Functional Safety Assessment (FSA) is a requirement of
the standards IEC 61508 and IEC 61511, but little understood and often causes
confusion and delays.
xSeriCon’s approach to FSA is systems-focused rather than compliance-focused; in
other words, we ask “Is the right approach being followed?” rather than “Is every
requirement met?”.
A well-executed FSA adds value, while covering hundreds of issues and can be a
major and challenging task. We work with clients from the earliest stage, providing
clear insight into our expectations as FSA Assessors, and guiding your team to
develop efficient processes and deliverables—helping you reach critical project
milestones without delay.
FUNCTIONAL SAFETY AUDIT
Procedures, such as the Functional Safety Management Plan and the Management
of Change procedure, are an essential tool to minimize the likelihood of systematic
failures in the Safety Instrumented System. Audits are a mandatory part of the
Functional Safety Life Cycle, to ensure compliance with these procedures.
xSeriCon is ready to support your functional safety journey with independent audit
services. If you prefer to handle auditing in-house, we can offer audit checklists,
procedures and guidance.
Verification, a required activity within the safety lifecycle, involves confirming that each lifecycle phase has generated the expected outputs, given the inputs and procedures.
xSeriCon with our fluency with the Safety Lifecycle is well-equipped to provide verification services to ensure that the client’s implementation of the safety lifecycle is of the highest standard.
SIS VALIDATION
When installation and commissioning of the Safety Instrumented System (SIS) is
complete, a formal validation exercise should be performed to ensure the as-built
SIS meets all the requirements of the Safety Requirements Specification. This highly
challenging task involves:
– Preparing a test and inspection checklist
– Collecting test data already generated (e.g. from the Factory Acceptance Test)
– Ensuring any gaps in the test and inspection are completed
A SIS Validation Plan should be prepared at an early stage in the Functional Safety
Life Cycle, to ensure testing is done and recorded in sufficient detail to make SIS
Validation quick and efficient. This helps to avoid delays at the critical pre-startup
phase.
xSeriCon’s experienced team can support your SIS Validation by preparing a
checklist, a validation plan and procedure, reviewing test data to confirm all aspects
are closed out, and guiding the team if further pre-startup testing and inspection is
required.
OPERATIONS & MAINTENANCE STRATEGY
This document is a plan for managing all functional safety-related tasks required during the
operational lifetime of the plant. These tasks include:
- Operator training relating to the SIS
- Competency management for operators, maintenance personnel, and engineers responsible
for modifications to the SIS - SIS testing, maintenance and repair
- Tracking of the performance of the SIS, and comparison with the assumptions made during
the hazard analysis and SIS design phases - Management of Change
- SIS partial decommissioning.
If these issues are properly covered in a dedicated Operations & Maintenance Strategy (O&MS), this helps to make the Functional Safety Assessment (FSA) smoother.
xSeriCon’s experienced team can support your project by providing a typical document structure and wording for the O&MS, or developing a complete O&MS for your project.
SAFETY LIFE CYCLE VERIFICATION
Verification is the task of confirming that each phase of the functional safety life cycle
has been properly executed, delivering outputs that are complete and correct. Done
properly, it requires a highly detailed and timely review to capture errors and
omissions before proceeding further with the life cycle.
Verification is one of the most important tools for assuring the performance of the
Safety Instrumented System. Yet, verification is little understood and often
neglected. In many projects, verification is left to the last minute before startup, when
most of its added value is lost.
xSeriCon’s experienced team can help you draw up a verification plan that is efficient
and delivers maximum benefit for minimum effort. We can execute verification for
your project’s life cycle phases, or provide training and review to ensure verification
is adequately performed in-house.
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