Solutia UK Ltd (A wholly owned subsidiary of Eastman Chemical) operates a number of batch and continuous plants at the site in Newport South Wales. They manufacture a range of products used as heat transfer fluids and in washing powders, floor coverings, safety windows and windscreens. The site is ‘top tier’ under the COMAH Regulations due to storage and processing of a number of hazardous substances including Phosphorous Trichloride and Benzene.
In 2000 Solutia were faced with the requirement to prepare the first COMAH safety report for the site and the challenge of identifying all the credible major accident hazards and associated risk control systems. ABB Consultancy was selected based on its’ expertise in hazard identification and
risk assessment. To ensure local ownership Solutia asked ABB to work with site engineering staff to develop their knowledge and competency. This allowed the Safety Report to be completed in-house giving ownership and facilitating updates on a 5-yearly cycle.
The initial requirement was to identify all the credible major accident hazards related to the storage and processing of COMAH dangerous substances, with the information then used by Solutia specialist staff to compile the site safety report. ABB advised the use of PHR on all the relevant
plants, providing a time efficient and structured method to identify credible ‘loss of containment’ scenarios.
A series of PHR’s covering all plants on the Newport site were carried out during 2000-2001, led by an ABB specialist with a team of experienced Solutia technical and operations staff. The scope meeting set the scene by gathering information on the systems to be included in the review, hazardous properties of substances, vulnerable locations on and off-site, emergency facilities, and the history of process safety incidents on the plant.
Using process P&ID’s, team based sessions were carried out to identify potential ‘loss of containment’ events on each system on the plant. For each credible event, the severity was estimated, the existing risk controls measures for prevention and mitigation were identified, and the resultant likelihood and risk assessed using the standard Solutia risk matrix. The review was used to confirm that relevant good practice was being followed, and resulted in several recommendations for further assessment of hazards or improvements to risk control systems.
The methodology used for the revalidation considered each process system and reviewed the following items; status of actions from previous review, learning from incidents onsite or elsewhere, thorough assessment of the implications of changes / projects, new knowledge on this plant, and
any current operational issues. If the original PHR was considered inadequate the option was available to re-do the review, and this was used on one plant to assess a complex reaction sequence using a step-by-step batch HAZOP study approach.