Attention all safety product listings
I received an e-mail inquiring about a product being “listed” or not, which made me stop and think about how far we have come in the past 10 years regarding safety systems and their “type” of certification.
The term “listed” means equipment or materials included in a list published by an organization engaged in product evaluation, that maintains periodic inspection of production of listed equipment or materials, and whose listing states either that the equipment or material meets appropriate standards or has been tested and found suitable for use in a specified manner.
While “listed” might sound appropriate for some, many safety experts would argue that today, it’s not enough. Since the release of the International Electrotechnical commission (IEC) 61508 – Functional Safety – Safety Related Systems in 2000, safety performance criteria is now better defined in the terms of SIL (safety integrity levels).
Hopefully you can appreciate that today’s safety products need to meet two key requirements (i.e. functional and performance). Functional requirements will describe what the product is supposed to do, while performance requirements define just how well it’s supposed to do it.
Take for example one of your NFPA 85 standards. Along with the functional requirements, this standard also describes about 10 types of system failures (Failure effects). Worse yet, it states that the system logic designer (i.e. your system integrator) needs to ensure that these failures are covered. While I agree it was a good attempt, it by no means describes how “good” the detection of these failures has to be. That’s pretty much what “listed” gets you these days.