By Kobus Vermeulen, direct sales executive, process automation at Schneider Electric, edited by Eamonn Ryan
In the HVAC industry, safety is as critical as efficiency. From chillers to industrial air handling units, the reliability of safety systems ensures not only uninterrupted operations but also the protection of personnel and equipment. Understanding the evolution of industrial safety systems offers HVAC engineers and facility managers valuable insights into designing resilient and high-integrity systems today. This is part one of a two-part series.
Kobus Vermeulen, direct sales executive, process automation at Schneider Electric. Supplied by Schneider Electric
One only has to briefly page through the annals of our industrial history, to come across truly hair-raising stories of safety systems failing or underperforming with catastrophic repercussions.
Fortunately, industrial safety in the last few decades has undergone some truly profound development. What began as simple hardwired trips – designed to prevent disasters – has become sophisticated ecosystems comprised of fault-tolerant, high-integrity platforms, all driving modern operational resilience.
But as the well-known saying goes: “to move forward, you must first look back”. In the 1980s, safety systems were dominated by hardwired shutdown circuits and early PLC-based schemes. Their limitations were widely felt across petrochemicals, power generation and other high-risk sectors.
The result, singe-point-of-failures were endemic; one faulty relay or controller could compromise the entire safety function. With no fault tolerance, even a minor component issue could force a plant shutdown, producing huge availability penalties.
Also, diagnostics were rudimentary, making latent failures hard to detect, while systems were rigid and difficult to modify. Any change required physical rewiring which was expensive, slow and downright disruptive.
Whichever way you look at it, these systems were not designed to meet the integrity expectations we now associate with modern functional safety frameworks. With no recognised Safety Integrity Level (SIL) structure at the time, operators were often forced to choose between higher risk or reduced uptime.
