5 things to consider when selecting a safety system

Performance requirements now drive the selection process

10/29/2013


Hazard management in places like offshore drilling is critical to the safety of people and property, and is one of five considerations when choosing a safety system. Courtesy: ABBSafety is among the top priorities in any manufacturing facility, and given the changes in the industry, technology and even standard, there are a lot of concerns starting with the selection of a safety system.

The performance based safety standards (IEC61508 and IEC61511/ISA84) have changed the way safety system selection should happen. Gone are the days of simply choosing a certified product, or selecting a preferred architecture; today’s system selection is driven by performance requirements. 

1: Hazard understanding

Correct, this has nothing to do with the safety system hardware. It is critical in the process to understand the scope of the process hazards and to determine the necessary risk reduction required. This should be done to create the Safety Requirements Specification (SRS) necessary to start a system selection. Even when replacing an existing system, this is critical as the risk profile of the plant may have changed since installation. 

2: The more diverse the better

Technology diversity: There has been a long standing requirement that a safety system must be different (or diverse) technology from its process automation counterpart to avoid common cause failures. But most safety systems rely on component redundancy (hardware fault tolerance, or HFT) to meet reliability and availability requirements, introducing a degree of common cause failure directly into the safety system.

Rather than redundancy, leading systems now provide diversity of technologies designed into logic solvers and I/O modules, along with a high degree of diagnostics, to allow a simplex hardware configuration to meet SIL3 requirements.

Product implementation diversity: The standards are imposing diversity on the way manufacturers deliver the product you buy. Even though most safety systems are manufactured by process automation vendors, organizational diversity between the two product teams is only the first level of separation.

Within the safety product team, leading suppliers will also be separating the design group from product development group and then again from product testing group. Ask your potential suppliers how diverse they really are? 

3: Systematic safeguards

This addresses how much protection against mistakes is built into the safety system. You should be asking for:

  • certified software libraries that offer functions according to the SIL requirements of the application,
  • compiler restrictions to enforce implementations according to the SIL requirements,
  • user security management to separate approved from non-approved users for overrides, bypass and other key functions,
  • and, audit trail capability to record and document changes to aid in compliance with functional safety standards 

4: Availability

As mentioned above, previous generations of safety systems met reliability requirements through HFT. This feature helped to provide availability and kept plants running in the event of a component failure with the safety system. Whether you needed it or not, you paid for it. Understand if you need high availability or not as some processes can easily tolerate shutdowns from spurious trips when using simplex configurations that still deliver appropriate SIL coverage.

If you know you need availability, look for a system supporting firmware update or upgrade and maintenance without disrupting the process. 

5: Separate, interfaced, or integrated?

Using the SRS and your business requirements, make a clear determination of one of these three requirements. Integrated offers many key benefits, drawing on common capabilities of the process automation system not related to the safety functions directly. But only being interfaced or even kept completely separate are options, and need to be thoroughly considered.

However, achieving the desired risk reduction involves more than just choosing a system. On our next posting we’ll cover implementation, security, operation, and maintenance of a safety system. 

Luis Duran is Product Marketing Manager at ABB for the Safety Automation System business.



Top Plant
The Top Plant program honors outstanding manufacturing facilities in North America.
Product of the Year
The Product of the Year program recognizes products newly released in the manufacturing industries.
System Integrator of the Year
Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
June 2018
2018 Lubrication Guide, Motor and maintenance management, Control system migration
May 2018
Electrical standards, robots and Lean manufacturing, and how an aluminum packaging plant is helping community growth.
April 2018
2017 Product of the Year winners, retrofitting a press, IMTS and Hannover Messe preview, natural refrigerants, testing steam traps
June 2018
Machine learning, produced water benefits, programming cavity pumps
April 2018
ROVs, rigs, and the real time; wellsite valve manifolds; AI on a chip; analytics use for pipelines
February 2018
Focus on power systems, process safety, electrical and power systems, edge computing in the oil & gas industry
Spring 2018
Burners for heat-treating furnaces, CHP, dryers, gas humidification, and more
April 2018
Implementing a DCS, stepper motors, intelligent motion control, remote monitoring of irrigation systems
February 2018
Setting internal automation standards

Annual Salary Survey

After two years of economic concerns, manufacturing leaders once again have homed in on the single biggest issue facing their operations:

It's the workers—or more specifically, the lack of workers.

The 2017 Plant Engineering Salary Survey looks at not just what plant managers make, but what they think. As they look across their plants today, plant managers say they don’t have the operational depth to take on the new technologies and new challenges of global manufacturing.

Read more: 2017 Salary Survey

The Maintenance and Reliability Coach's blog
Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
One Voice for Manufacturing
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Maintenance and Reliability Professionals Blog
The Society for Maintenance and Reliability Professionals an organization devoted...
Machine Safety
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
Research Analyst Blog
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Marshall on Maintenance
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
Lachance on CMMS
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
Electrical Safety Update
This digital report explains how plant engineers need to take greater care when it comes to electrical safety incidents on the plant floor.
Maintenance & Safety
The maintenance journey has been a long, slow trek for most manufacturers and has gone from preventive maintenance to predictive maintenance.
IIoT: Machines, Equipment, & Asset Management
Articles in this digital report highlight technologies that enable Industrial Internet of Things, IIoT-related products and strategies.
Randy Steele
Maintenance Manager; California Oils Corp.
Matthew J. Woo, PE, RCDD, LEED AP BD+C
Associate, Electrical Engineering; Wood Harbinger
Randy Oliver
Control Systems Engineer; Robert Bosch Corp.
Data Centers: Impacts of Climate and Cooling Technology
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
Safety First: Arc Flash 101
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
Critical Power: Hospital Electrical Systems
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
click me