Hazardex 2018 Conference - 18. Fire detector mapping – What metrics should we be using?
31 January 2018
Tim Jones - Senior Consultant, MMI Engineering.
Thurs 14.45 – 15.25: Main conference room
Fire and gas detector mapping using computational methods has become more and more common in hazardous industries in recent times. Despite the advances in the technology and methods associated with such mapping, one of the most important aspects is how we deem a detection system adequate with respect to the coverage it provides.
At present, there is little guidance given by the UK HSE or other industry bodies on the definition of coverage and how it should be achieved. As a result, companies use their own internal standards and methodologies, which can vary significantly in efficacy. These company standards typically measure the performance of fire detector systems in terms of percentage coverage over a particular volume.
This may seem a reasonable metric but it misses the most important factor, namely the size of the gaps that the detectors do not cover. It is the size of the gaps in your system that is going to dictate whether or not your system is able to detect a fire of a size that may lead to escalation. A fire area could have a very high percentage coverage but still have gaps where a significant fire could exist.
This paper aims to show the deficiencies in measuring detector coverage based on percentage coverage alone and presents the advantages of alternative methods, such as optimising your system to ensure that no fire above a certain size can go undetected. The work presented within this paper uses MMI’s in-house fire detection code which uses ray casting techniques in a fully three-dimensional manner to account for obstructions that block a detector’s line-of-sight.
Tim Jones has Masters degrees in Mechanical Engineering, Process Safety and Loss Prevention, all from the University of Sheffield. He joined MMI Engineering 11 years ago and is a Principal Consultant based in the Warrington office in the UK. Before joining MMI, Tim worked for BAE Systems for three years in a number of analytical roles.
His area of focus is fire and explosion management in the oil and gas, nuclear and pharmaceutical industries and he has experience in safety assessments of both onshore and offshore facilities. His main area of expertise is hazard modelling and probabilistic analysis, including explosion, gas dispersion and fire modelling using CFD and phenomenological methods. The variety of projects that Tim has worked on has led to him gaining experience at all stages of the project lifecycle, including FEED, detailed design and Brownfield.
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