What are the best practices for designing and installing instrumentation to prevent fire and explosion risks?

When designing and installing instrumentation to prevent fire and explosion risks, it is essential to adhere to best practices for safety. Start by conducting a thorough hazardous area classification, following guidelines such as IEC 60079 for explosive atmospheres. Prioritize the use of intrinsically safe instruments and employ enclosures compliant with NEMA standards to contain potential explosions. Ensure compliance with API standards, including API 500 and API 505, for wiring, grounding, and emergency shutdown systems. By incorporating these standards, the systematic approach addresses hazardous area classification, explosion-proof designs, and other key aspects, ensuring a high level of safety in potentially risky environments.

One key, and also one of the most often overlooked elements in efficient and effective PSM, in my opinion and experience, is to involve and include the personnel that has, and will be directly and immediately affected by the PHAs, SOPs, and Emergency Response Procedures. The operators of the facilities and equipment being designed (whether new technology or tried and tested) can provide extremely valuable insight concerning every aspect of the installation. The combining of hands on experience, and knowledge (both operational and engineering) is a priceless asset that all too often is not taken advantage of.

Designing, selecting and installing instrumentation in order to minimize the risk of fire and explosion: 1. Explosion Degree and instrument SIL level to be selected based on hazardous area classification and SIL assessment 2. Use intrinsically safe or explosion-proof equipment rated for the specific hazardous area classification. 3. Compliance with Standards such as NFPA, IEC, and ATEX guidelines. Ensure correct instrument installation based on vendor installation/maintenance manual.

Simply we can see instrument hazards are coming from sources of ignition which we will find during failure or malfunction of instrumentation. And we can eliminate this through: 1) Use proper instrument SIL Rate based on (hazardous zones). 2) Provide a programed PM and immediate CM when require. 3) Make sure you equipment comply with relevant standards (e.g., IEC 61508).

To effectively prevent fire and explosion risks in instrumentation design and installation, Hazard identification is a crucial step in preventing fire and explosion risks. it is essential to follow a structured hazard identification process. By employing a combination of methods like HAZOP, FMEA, FTA, and LOPA, and adhering to industry standards such as IEC 61511, API 505 and IEC 60079, Adherence to these standards ensures that instrumentation systems are designed and installed with the necessary safety layers to minimize risks. This comprehensive approach ensures a safer operating environment.

In my experience, in addition to HAZOP workshops which manages hazards at static mode, it’s important to adopt a strategy during the concept/design stage of the project that identifies and manages transient modes during shutdowns, start up, maintenance since much of the process safety incidents occur at that phase of the project or mode. An operations mode analysis review will help identify instrumentation/process hazards when switching from steady to transient modes and possible mitigations in place.

PPE is not a hazard control measure for instrumentation. There are no references to DSEAR/ATEX or the selection of instrumentation depending on the zoning of the area, and the selectivity of the instrumentation to suit.

There are a number of standards/guidance relevant to this question such as Functional safety of Safety Instrumented Systems (IEC61511) and Safety Integrity Levels. As well the ATEX standards for hazardous zoning and design of Ex rated equipment (BS EN 60079-xx series/ BS EN 13463). Other standards such as BS EN 1127 address explosion hazards more generally. I suggest that it would be appropriate for the article to begin by reviewing the guidance already in place. In terms of the original question I would say that inherently safer design and development of the hazard management strategy are important early in the design process so not to end up with onerous (and quite likely impractical) requirements for high SIL rated systems.

Subscribe to the PIP Process Industry Practices program developed by University of Texas at Austin. This Program is sponsored by and maintained “Up-to-Date” by the School of Chemical Engineering Faculty, Staff and Students (undergraduate, graduate, doctoral , and in-residence post doctoral students). Robert E. Sherman ISA Fellow 2002 ISA Life Fellow 2016 International Award Recipient Kermit Fisher Award International Continuous Emission Monitoring Systems