• TECH TALK •
Cracking Units: Safety Perspective – Part Two
It is widely recognized that even well-designed systems can fail if they are difficult to operate or prone to human error.
In FCCUs, where isolation activities may be performed under time pressure, in challenging environments, and by personnel who may interact with a particular piece of equipment only once every several years during a turnaround, the design of isolation systems must actively facilitate correct operation.
This includes providing unambiguous labeling of all isolation points, minimizing the number of sequential steps required to achieve a safe state, and ensuring valves are located in accessible and ergonomically acceptable positions.
The use of remote-operated valves and automation further reduces the need for direct human intervention in hazardous areas. Hydraulic power units( HPUs) used to actuate FCCU slide valves have been progressively upgraded at many facilities to improve reliability and meet current best practice standards for response time and fail-safe functionality.
Field verification of valve closure, including the use of position indicators and stroke testing, is recognized as an essential layer of assurance.
6. Digitalization and Smart Isolation Systems
Digitalization plays an increasingly important role in modern isolation practices. Advances in instrumentation and control systems enable the development of smart isolation systems that provide real-time feedback on valve position and mechanical condition.
These systems can be integrated with distributed control systems( DCS) and electronic permit-to-work platforms, providing a verifiable record of isolation status before maintenance activities begin. The integration of valve position feedback into the permit-to-work workflow reduces the risk of proceeding with maintenance on equipment that has not been correctly isolated.
Predictive maintenance techniques, drawing on data analytics applied to valve performance records, vibration signatures, and diagnostic outputs from smart valve positioners, are being used to identify trends in valve condition degradation before they progress to failure.
Considering that slide valves provide the ability to monitor valve condition continuously and plan intervention at the optimal point in the asset lifecycle is a significant advancement.
Digital twin modeling of FCCU isolation systems is an emerging area that offers potential for further improvement in the reliability and effectiveness of isolation strategies.
7. Regulatory Framework and Industry Standards
The selection of an appropriate isolation strategy requires a careful balance of safety, operability, and cost. In the U. S., the Occupational Safety and Health Administration( OSHA) Process Safety Management( PSM) standard( 29 CFR 1910.119) establishes the foundational regulatory requirement for the management of highly hazardous chemicals, including the development and implementation of written procedures for isolation.
Field verification of valve closure, including the use of position indicators and stroke testing, is recognized as an essential layer of assurance.
The PSM standard ' s requirement for hazard analysis, management of change, and pre-startup safety review all have direct relevance to isolation system design and verification.
Valve World Americas | May 2026 | www. valve-world-americas. com 29