CHEMICAL ENGINEERING TRANSACTIONS
VOL. 77, 2019
A publication of
The Italian Association
of Chemical Engineering
Online at www.cetjournal.it
Guest Editors: Genserik Reniers, Bruno Fabiano
Copyright © 2019, AIDIC Servizi S.r.l.
I SBN 978-88-95608-74-7; I SSN 2283-9216
Achieving World Class Performance in Oil and Gas Industry
Using Inherently Safer Design
SreeRaj R Nair
a,
*, Karel Schnebele
a
, Hari Attal
b
, Noma O Ogbeifun
b
a
GOM BU, Chevron USA Inc, Houston, USA
b
ETC, Chevron, Houston, USA
snair@chevron.com
Hazard Identification, consequence evaluation, risk mitigation analysis, and management of effective
safeguards are key to effective risk (safety) management. The high hazard industry, in its quest to achieve
safer operations, has developed several risk assessment techniques that prescribe the addition of safeguards,
usually safety systems, as the primary means to mitigate risk. This has led to complexity and not necessarily
safer plants as evidenced by a trail of major process safety incidents.
High profile incidents with associated asset losses, increased public concern on safety issues and changes to
regulatory expectations have driven the industry to consider inherently safer design (ISD) options. Chevron,
on its journey to achieve world class operations, has adopted and deployed ISD principles during the
execution of major capital projects (MCPs). As early as the alternatives generation stage of a MCP, projects
rigorously evaluate options that allow for simpler and robust facility design.
This paper is based on the systematic application of ISD principles in offshore MCPs. The paper share
examples of how ISD was applied in early MCP engineering phases and the benefits of the structured ISD
application.
1. Introduction
An ‘inherently safer’ approach to hazard management is one that strives to avoid or eliminate hazards, or
reduce their magnitude, severity or likelihood of occurrence, by careful attention to the fundamental design
and layout. Less reliance is placed on ‘add-on’ engineered safeguard and procedural controls (Energy Institute
2014). High hazard industries promote a ‘hierarchy of control’s’ approach where inherently safer design is
preferred above the other principles of engineered (passive and active) and procedural controls for prevention,
control and mitigation. Inherently safer design (ISD) in process industries dates back to the 1970s and have
formal origin in Trevor Kletz’s lecture titled ‘What you don’t have, can’t leak’. The concept got further
developed over years and related rules of thumb have been developed including ‘Who is not there, can’t be
affected’ (Nair, 2007), ‘What you don’t have doesn’t cost anything, won’t break down or won’t need
maintaining’ (Energy Institute 2014) and ‘More is not always safer’ (Nair, 2017). In their paper at 7th Global
congress on process safety, Amyotte et. al. analysed United States Chemical Safety Board’s investigation
reports and identified that 36% of the incidents were related to failure to incorporate inherent safety in both
incident prevention and consequence mitigation (Amyotte et. al., 2011).
Table 1: ISD fundamentals
Strategy How?
Eliminate Eliminate the hazard – material or activity
Substitute Replace a hazardous material or process with an alternate that reduces hazard severity
Minimize Use smaller quantities of hazardous substances or reduce inventory or energy to reduce the severity
Moderate Use dangerous material in their less hazardous form or identify options with less severe conditions
Simply Designing processes equipment and procedures to eliminate unnecessary complexity and potential
human errors
DOI: 10.3303/CET1977129
Paper Received: 11 November 2018; Revised: 7 May 2019; Accepted: 22 June 2019
Please cite this article as: Nair S., Schnebele K., Attal H., Ogbeifun N., 2019, Achieving World Class Performance in Oil and Gas Industry Using
Inherently Safer Design, Chemical Engineering Transactions, 77, 769-774 DOI:10.3303/CET1977129
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