CHEMICAL ENGINEERING TRANSACTIONS VOL. 56, 2017 A publication of The Italian Association of Chemical Engineering Online at www.aidic.it/cet Guest Editors: Jiří Jaromír Klemeš, Peng Yen Liew, Wai Shin Ho, Jeng Shiun Lim Copyright © 2017, AIDIC Servizi S.r.l., I SBN 978-88-95608-47-1; I SSN 2283-9216 The Application of First and Second Orders of Inherent Safety in the Chemical Process Industry Zafirah Zakaria a , Kamarizan Kidam* ,a,b , Mimi Haryani Hassim a,b , Onn Hassan a , Haslenda Hashim a a Department of Chemical Engineering, Faculty of Chemical and Energy Engineering, Universiti Teknologi Malaysia, Malaysia b Centre of Hydrogen Energy, Institute of Future Energy, Universiti Teknologi Malaysia, Malaysia kamarizan@cheme.utm.my The inherent safety (IS) concept has been introduced for more than 45 years, yet its adoption into process design is still very low. As a result, similar accidents keep on occurring worldwide since a majority of the risk reduction strategies used are based on the outer layers of protection such as active engineered and procedural. To enhance the uptake of inherent safety into chemical plant design, this paper aims to outline the common inherent safety strategies that have been used by the chemical process industry (CPI) to prevent accidents. 502 cases of inherently safer design (ISD) applications in the CPI have been collected and analysed. The process changes through plant modification are grouped based on the four main ISD strategies of minimisation, substitution, moderation, and simplification. The four main ISD keywords are then further classified into a hierarchy of inherent safety order. 58 cases (12 %) fall under first order IS which is from substitution keyword. For the 2nd order IS (magnitude), the keyword minimisation gives 242 cases (48 %) while moderation gives 151 (30 %). The simplification keyword which is under 2nd order IS (likelihood) gives 51 cases (10 %). The 2nd order IS (magnitude) seems to give the biggest numbers of design changes made by the CPI. Magnitude reduction strategy is the common choice by the CPI when designing safer equipment or process. 1. Introduction The modern accident prevention strategy basically adopts the layers of protection concept. For example, a simplified risk assessment for chemical plants which prepared by Argenti et al. (2015) applied layer of protection (LOPA) approach to access the factors that influenced the accidents occurrence. There are four basic layer of protection which begin with inherent safety. The next layer is passive engineered, followed by active engineered and lastly is procedural. To compare between four layers, inherent safety is said to be the most reliable. The concept of IS has been introduced since 1970s by Trevor Kletz as an effort of designing processes in a safe condition by its nature rather than adding on active and passive control device. A research that compiled papers from 2001 - 2011 which discusses about IS at a different perspective shows a positive rise (Srinivasan and Natarajan, 2012). Despite having attention and argument over its implementation, inherent safety concept is not practically applied yet (Mannan et al., 2015). The concept is widely believed as the most effective strategy in eliminating hazards, but the uptake is slow and similar accidents keep occurring from time to time. There could be a list of issues that leads to a slow uptake of its implementation and the reality of its being too conceptual are related to the flaw of design process. This is mainly due to the lack of understanding on how to implement ISD in design projects. The information on the existing efforts made by companies is not easily accessible since most of the new design projects are declared as confidential. The new or latest ISD implementation in real industries is poorly disseminated to the process community. In this study, the main objective is to provide a better understanding on current status of ISD which has been implemented in the DOI: 10.3303/CET1756138 Please cite this article as: Zakaria Z., Kidam K., Hassim M.H., Hassan O., Hashim H., 2017, The application of first and second orders of inherent safety in the chemical process industry, Chemical Engineering Transactions, 56, 823-828 DOI:10.3303/CET1756138 823