Modernization: Upgrading a BMS to a SIL3 PLC system

Modernizing an existing BMS to a Schneider Modicon 580 Safety PLC to be compliant with FM Global & CSA B149.3:20 standards.

An end user needed to upgrade their Burner Management System (BMS) to meet their company’s SIL3 safety standards and therefore selected a PLC with a SIL3 rating. The BMS vendor did not have the experience given the safety rating, so they turned to InnoTech to provide the necessary expertise. InnoTech provided the panel design, PLC programming, HMI development, and commissioning support. Effective collaboration resolved I/O discrepancies and design issues, ensuring on-time delivery. The end user’s BMS is now compliant, and the BMS vendor gained a framework for future projects.

Situation

Our customer’s client’s existing Burner Management System (BMS) required an update to meet current industry standards (compliant with both FM Global and CSA standards (B149.3). They completed a HAZOP, revealing that some of the process loops required either a SIL2 or SIL3 (Safety Integrity Level) rated PLC system. The end user chose a Schneider Modicon M580 Safety PLC for the project, so to ensure that the system would be installed during a planned turnaround in mid-September, our client had 3.5 months to complete the project.

Risks

The BMS needed to be brought up to code to avoid any non-compliance issues, and the project needed to be implemented by the scheduled commissioning date to avoid unnecessary downtime.

InnoTech Selection

However, the BMS vendor did not have experience with BMS installations for systems at this SIL rating (unfamiliar with the SIL rating calculations and the multiple I/O points associated with the PLC). The BMS vendor came to InnoTech, knowing that our team has trusted processes and procedures along with the expertise in programming safety systems and meeting SIL standards required for BMS Systems. So, the InnoTech team was subcontracted to deliver tailored engineering solutions to bring this burner management system up to code.

Task and Scope

The system selected by the end user, a Schneider Modicon M580, was chosen because it is highly reliable, meets their desired Safety Integrity Level rating of 3 (SIL3), and could be delivered on time. InnoTech provided engineering solutions that included:

1. Burner Management System control panel design

• • PLC Panel layout drawing
  • PLC Panel bill of materials
  • PLC Panel Schematics

2. Burner Management System configuration

• • Functional Design Specification – PLC & HMI
  • Boolean Logic Diagrams
  • Data Transfer List
  • Alarm List
  • Programmable Logic Controller (PLC) Programming – M580 Safety PLC
  • Local Human Machine Interface (HMI) Programming

3. Factory Acceptance Test plan development

4. FAT Acceptance Test

5. Commissioning and site support.

Actions Taken

The InnoTech team leveraged the BMS vendor’s standard BMS design and our experience with SIL-rated PLC systems to complete the project.

Analysis and Comparison

The InnoTech team analyzed the BMS vendor’s initial design against one of their pre-existing typicals[1]. Discrepancies in I/O points were identified, prompting in-depth discussions to ensure that all the necessary I/O were included, and all the unnecessary I/O were removed.

Panel Design Revision

The existing typical designs did not account for SIS hardware, so the panel design was rearranged in order to incorporate this. Revisions were reviewed and approved by the client to finalize the design.

Effective Communication

Continuous communication with the client’s project team facilitated quick decision-making and periodic reviews, keeping the client up-to-speed for the Site Acceptance Test (SAT) and commissioning. Collaborating closely with the customer to capitalize on the expertise of both organizations helped to streamline the engineering process. A significant factor in the success of this project.

HMI Programming

The team programmed the Human-Machine Interface (HMI) using RedLion, creating the display and connections to ModBus units from scratch, ensuring that it met the end user’s requirements through collaborative reviews.

Procurement

The InnoTech team quickly mobilized to get the hardware requirements finalized and placed the order for the safety system. Thanks to the PLC vendor, the hardware was delivered in just 6 weeks. Enough time to fabricate the PLC cabinet and complete the FAT, while maintaining the project schedule.

Challenges

Timeline

Implementing a SIL3 system was decided late into the design process, creating a great deal of engineering rework and giving InnoTech and our client only 3.5 months to complete the project for the planned shutdown in September.

Parallel engineering

The mechanical and process work by the BMS vendor was being executed in parallel to the engineering design. This created a lot of rework in getting stamped inputs and filling in the gaps to complete the design.

Custom design needs

There was misalignment in the provided typical and the proposed design, which required much customization for it to work with the end customer’s facility.

Results from the Burner Management System upgrade

The solution was successfully delivered in time for commissioning. The client’s BMS is now up to the required safety standard, and the BMS vendor now possesses a comprehensive typical for implementing a BMS with an SIS system that includes:

• Panel layout
• Bill of Materials (BOM)
• Wiring for power and I/O
• Power supply alarms
• Module and special drawings

The new framework enables our client to implement similar systems efficiently and easily, enhancing their ability and confidence to manage SIS BMS projects.

Discussion Question

What strategies can engineering teams implement to effectively manage parallel workflows and minimize rework in complex projects like the implementation of a Burner Management System?

[1] A Typical is the standard specifications for design, materials, and processes that the client follows for products based on similar applications.

Originally published February, 2025. Updated May, 2026.