On offshore installations the successful detection of an uncontrolled release of flammable gas is one of the last lines of defence against fire and explosion events. A brief analysis of UK continental shelf (UKCS) offshore hydrocarbon release (OHR) statistics during 1992-2015 shows that an appreciation of performance of currently installed gas detection arrangements is of paramount importance, since almost half (48.5%) of the recorded accidental gas releases were apparently not detected by the fixed gas detection systems in place. Detection results for experimental, simulated gas leaks are compared with the offshore statistics finding that the experiments demonstrate ~97% successful detection rate, highlighting the disparity between research and real offshore experience. The experimental simulations are conducted for the traditionally recommended target gas cloud (TGC) detector arrangement at 5 m spacing. We have reasoned that such experimental work is of limited benefit if the same detector approach is not applied offshore. No research has investigated this issue or considered the impact of actual detector layouts upon the detection performance statistics. We have evaluated 27 real offshore gas detector layouts from 18 facilities and found that the TGC approach is present in less than 50% of cases and less than 50% of those achieve typical coverage targets. This is a simple yet important finding previously unaddressed in industry or in literature. In addition, a preliminary review of the statistics demonstrates little or no evidence to corroborate prevailing industry anecdote that low overall detection is due to the high number of small leaks which are not the true target of the detection system. We recommend that detector layouts be submitted by operators during hydrocarbon release reporting so that this missing link in the analysis of the performance of offshore detection can be fundamentally understood, and the issue of detection performance can finally be addressed.

International Seminar on Fire and Explosion Hazards (9; 2019; Saint Petersburg, Russia). Proceedings of the Ninth International Seminar on Fire and Explosion Hazards [Электронный ресурс]: 21-26 April 2019, Saint Petersburg, Russia. Vol. 2 / Peter the Great St. Petersburg Polytechnic University, Autonomous Non-Profit Organization "Fire and Explosion Safety", Gefest Holding Ltd ; [edited by A. Snegirev [et al.]. — Электрон. текстовые дан. (1 файл : 98,7 Мб). — Saint Petersburg, 2019. — Загл. с титул. экрана. — Свободный доступ из сети Интернет (чтение, печать, копирование). — Adobe Acrobat Reader 7.0. — <URL:http://elib.spbstu.ru/dl/2/k19-97.pdf>. — <URL:http://doi.org/10.18720/SPBPU/2/k19-97>.