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A Modification to the SISSafety Instrumented System is anything that is not like-for-like replacement. “Like for like” here means the same component (hardware and firmware version), from the same supplier.

The “same” product from a different supplier (or even a different version of the product from the same supplier) should trigger the Management of Change (MoC) process for the SIS.

As Modifications come in many different shapes and sizes, the approach defined in IEC 61511 is designed to be flexible and is a “one size fits all” approach. While the level of effort to approve the use of a new variant of a device from the original manufacturer would be quite low, and the effort to approve the introduction of a new SIFSafety Instrumented Function to a SIS would be quite high, the approach is flexible enough to handle both.

IEC 61511 requires a 2-stage FSA process to be carried out on Modifications. The first stage confirms that the proposal of implementing the change is fit for purpose, prior to the start of the work. Once the Modification is completed, the second stage of the FSA confirms that the work was done correctly (as per the proposal).

What =Method can do for you

=Method can help you manage MoCManagement of Change for SIS (which is often not straightforward) and deliver Stage 5 Functional Safety Assessments.

Most recent projects for Modification

Stage 5 Functional Safety Assessment (FSA 5) on an offshore natural gas platform located in the southern North Sea.

Industry: Oil and Gas Offshore
Topic: Functional Safety Assessment (Stage 5)

1-day review to implement modification to remove a SIF

Industry: FMCG
Topic: Functional Safety Assessment (Stage 5)

FSA 5 for modification to chemical process

Industry: Chemical
Topic: Functional Safety Assessment (Stage 5)

FSA 5 of chemical plant installation of new SIF instrumentation.

Industry: Chemical
Topic: Functional Safety Assessment (Stage 5)

View all of our recent projects here

Functional Safety Consultancy

=Method's specialist, expert consultants support industries across the entire Functional Safety Lifecycle. If you need help please contact us.

Functional Safety Training

=Method delivers training in public venues, In-house and online. See more about how we deliver training here.

Functional Safety Lifecycle

Assessments at key Lifecycle Stages - Functional Safety Management

Planning throughout the Lifecycle - Functional Safety Management

Verification at every Lifecycle Stage - Functional Safety Management
Hazard & Risk Assessment Allocation of Safety Funct's to Protection Layers Safety Requirements Specification Design & Engineering Installation, Commissioning & Validation Operation & Maintenance Modification Decommission
Functional Safety Management
Functional Safety Audit
What is Functional Safety?What is functional safety?
I am new to this, how do i start?What is functional safety?

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