Let's conclude our discussion about SIL by contemplating the answer to the following question..are you just trying to meet specifications or are you designing a safety system?
Companies in industries around the world are expected to produce safe products and provide a secure working environment. This can be achieved by anticipating hazards that might occur and creating a safety system to combat them. The approach a company takes to control the risks and liabilities that go along with these hazards is an essential part of the safety process.
Installing, operating, and maintaining an analyzer according to both the installation & safety manuals is a vital part of the safety system and necessary for obtaining the desired SIL level. So there is a symbiotic relationship between the concepts the question poses. Designing a safety system the right way will help you stay safe and productive while meeting the specifications.
Incorporating a PrevEx into your system can help you reach this goal. The role of PrevEx in functional safety is as a sensor. Its outputs are used by a “logic solver,” typically a relay or PLC in a safety shutdown (“E-stop” circuit), to trip “actuator(s)” such as fans, dampers, bypasses, machine stops, etc., that can prevent hazardous conditions or mitigate their effect. The SIL rating is the level of risk reduction that is achieved by the whole system – not just PrevEx, but the logic solver and actuators too. So when there’s a little risk, you need less reduction, and where’s there’s more risk, you need a lot.
- Control Instruments' has completed its functional safety certification through exida LLC. The certificate and assessment report for the PrevEx™ Flammability Analyzer are available on exida’s public website. The website’s Security Automation Equipment List (SAEL) is a regularly maintained list of instruments that currently have valid certificates. It contains information for incorporating a PrevEx analyzer into SIL 2 or SIL 3 safety instrumented systems. The listing for the PrevEx 670 Series Flammability Analyzer is here.