Reliability of on-line versus standby safety systems in process plants: a comparative assessment of two systems for controlling accidental gas releases

Ioannis A ,P; Aneziris, O

dc.contributor.author	Ioannis A ,P	en
dc.contributor.author	Aneziris, O	en
dc.date.accessioned	2014-03-01T01:40:00Z
dc.date.available	2014-03-01T01:40:00Z
dc.date.issued	1990	en
dc.identifier.issn	09504230	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/23055
dc.relation.uri	http://www.scopus.com/inward/record.url?eid=2-s2.0-0342966202&partnerID=40&md5=10dd5ac18120b30ae82ebf166452c5b0	en
dc.subject	control systems	en
dc.subject	release	en
dc.subject	reliability	en
dc.title	Reliability of on-line versus standby safety systems in process plants: a comparative assessment of two systems for controlling accidental gas releases	en
heal.type	journalArticle	en
heal.publicationDate	1990	en
heal.abstract	This paper presents a method for reliability assessment of on-line and standby control and safety systems in process plants, based on the principles of Markovian reliability analysis. Safety or control systems in process plants aim to prevent and/or mitigate possible deviations from normal operating conditions that could lead to accidents. On-line control systems operate continuously while standby systems are triggered by the onset of an accident. Two alternative designs for controlling accidental releases of hydrogen selenide (H2Se) and hydrogen sulphide (H2S) in the manufacturing of photovoltaic cells are compared. The on-line system, which consists of a Venturi scrubber, a packed bed scrubber, and a carbon adsorption bed, operates continuously and its failure is immediately detectable. The standby system is triggered by a toxic gas release, and failure is detectable only through demands (actual or tests). It consists of a containment (high pressure vessel), a scrubbing vessel and a carbon adsorption bed. The average unavailability over a one year period is calculated for both systems as a function of the failure rates, the repair rates, the frequency of testing and the probability of human errors. Regions of the parameter values within which each alternative design exhibits lower average unavailability are provided. © 1990.	en
heal.journalName	Journal of Loss Prevention in the Process Industries	en
dc.identifier.volume	3	en
dc.identifier.issue	2	en
dc.identifier.spage	212	en
dc.identifier.epage	221	en