Functional Safety Consulting

eXcelsior Safety can provide consultancy lifecycle services in the 11 categories which align 
with the Functional Safety Lifecycle Framework in the good practice standards.

Services Overview

Why Functional Safety is needed ?

To reduce the risk to people, to minimise damage to the environment and to reduce asset or financial risk.


Compliance with international Standards such as IEC 61508 and IEC 61511 is imperative to meet the Functional Safety requirements for many processes and is part of the Quality Management Systems of many companies.
Provision of Functional Safety Services in line with the Phases and Activities detailed in the Safety Life-cycle is an area in which our consultants have proven to have wide experience and expertise.

Functional Safety services can be categorised into main areas :
- Hazard and Risk assessment and management,
- Allocation of Protection Layers,
- Safety Requirements Specification,
- Control and Mitigation of Random and Systematic Failures,
- Architectural assessment and requirements.

The key to success in achieving a good Functional Safety service depends on several factors:

  • Quality of input information during Front End Engineering or Detailed Design stages,
  • Clear and both parties understandable scope of supplies,
  • Important site expertise of the safety engineers to understand client processes or machines as well as operation processes in helping to determine the right level of risks,
  • Large expertise in protection layers in terms of capacity and life cycle management,
  • Confidentiality and secured access control of the associated documentation.

eXcelisor Safety can support you with all your Functional Safety requirements.

Our Services

Process Hazard & Risk Analysis (PH&RA)

Qualitative hazard and risk analysis in support of IEC 61511 Phase 1 or IEC 61508 requirements.

Methods that could be used:
  • Checklist
  • What if ?
  • Hazard and Operability (HAZOP)
  • Hazard Indentification (HAZID)
  • Failure Mode and Effect Analysis (FMEA)
  • SIL Allocation

    Allocation of Safety Functions to protection layers using cause / consequence pairs from PH&RA.

    Methods that could be used :
  • Qualitative – Matrix Graphs, Risk Graphs
  • Semi-quantitative – Layer Of Protection Analysis (LOPA)
  • Fully quantitative – Fault Tree Analysis (FTA)
  • Safety Requirements Specification (SRS)

    Development or evaluation of the Safety Requirement Specifications for the provision of Safety Instrumented System (SIS) - Phase 3 of IEC 61511.
    Key document contains the functional and integrity requirements for each SIF and should provide sufficient information to design and engineer the SIS and include the following for each SIF.

    SIL Conceptual Design

    Design and Engineering consultancy for the Safety Instrumented System (SIS) in accordance with the requirements of IEC 61508 and IEC 61511.

    SIL Verification

    Reliability assessment and Architectural requirements for Safety Integrity Level (SIL) classified Safety Instrumented Functions (SIFs)

    SIL Verification can be carried out using various modelling techniques, including :
  • Reliability Block Diagrams (RBDs),
  • Fault Tree Analysis (FTA) and
  • Failure Mode and Effect Analysis (FMEA)
  • Prior-use / Proven-in-use

    For existing facilities or green field project, concept of prior-use or proven-in-use in evidence of compliance with IEC 61508 and IEC 61511.

    Functional Safety Assessment (FSA)

    Management of Functional Safety Assessment is separated into 5 stages in accordance with the requirements of IEC 61511.

    • Stage 1 – After H&RA has been carried out, the required Protection Layers identified, and the SRS has been developed complete.
    • Stage 2 – After SIS has been identified, designed & FAT completed.
    • Stage 3 – After Installation, pre-commissioning, final validation of the SIS has been completed & O&M. procedures have been developed.
    • Stage 4 – After gaining experience in operating and maintenance.
    • Stage 5 – After modification and prior to decommissioning of a SIS.

    Functional Safety Lifecycle & Management

    Functional Safety Lifecycle and Management are key to demonstrate how Functional Safety will be implemented and achieved.

    The objective of having a compliant functional safety management system is to ensure that all aspects, from process hazard and risk assessments (PH&RA) to decommissioning of the SIS are managed.

    Project Planning, Life Cycle & Value Improvement

    Developement of Project Lifecycle, Value Improving Practives (VIPs).

    Emergency Response, Escape & Evacuation Assessments

    Offshore and onshore Facilities including Chemical, Petrochem and Oil and Gas Facilities.

    Building Risk Assessment & Dropped Objects Studies

    Building Risk Assessment and Quantitative Dropped Objects Studies

    Reliability Availibilty & Maintainability Studies

    RAMS using various tools, methods and techniques

    Fire and Gas Assessment

    Fire and Gas Mapping, Modeling and Coverage Assessment

    Pre-Startup Safety reviews

    Oil & Gas Plant PSSRs, Chemical, Petrochemical and instrumented facilities