(46ad) Are You Being Honest with Yourself Regarding IPL Integrity?

Are You Being Honest With Yourself Regarding IPL
Integrity?

Mr.
Andrew Madewell
Cognascents
Consulting Group, Inc.
11777-A
Katy Fwy Ste 438
Houston,
TX 77079

andrew.madewell@cognascents.com

Keywords: Independent
Protection Layer (IPL), Process Safety Management (PSM), Layer of Protection
Analysis (LOPA), Process and Instrumentation Drawing (P&ID), Process Hazard
Analysis (PHA), Process Safety Lifecycle.

Abstract

Independent Protection Layers (IPLs) are critical pieces of
armor designed to protect against process upsets that may harm people, the
environment, and/or commercial interests. 
IPLs play a key role in any Process Safety Management (PSM) program.  They are often used to close the risk gap
between elimination/mitigation measures and associated hazard scenario causes
and consequences; hence, regulations exist that require companies to demonstrate
IPL integrity and adequacy.

When conducting a Process Hazard Analysis (PHA) using the
Layer of Protection Analysis (LOPA) methodology, IPLs are used to close the
risk gap between elimination/mitigation measures for a given hazard scenario
and its cause, consequence, and conditional modifiers.  In order for an IPL to be ?available?, it must
meet certain criteria defined by industry standards and company-specific
guidance documents. 

Demonstrating IPL effectiveness, or adequacy, involves
multiple pieces of information that are not always linked together and kept
?evergreen?.  In addition, the various
data repositories and tasks required to maintain the integrity of an IPL are
?owned? by several functional roles. 
Required data for IPL adequacy include the following: IPL design
information, IPL integrity level analyses, maintenance and function testing
data, and process safety time and IPL response time analyses. 

Companies do not approach IPL integrity the same way.  For example, companies perform IPL function
testing and maintenance using different criteria; some employ a standard
function testing methodology of confirmation that the IPL acts within the
designated time window per regulatory requirements, while other companies
actually measure the specific time it takes an IPL to respond to get to its
process safe condition.  Either of these approaches
provides compliance as to whether the IPL will act adequately given a process
upset; however, vulnerabilities may exist depending on the approach employed.

The author posits that use of an evergreen IPL lifecycle
reduces potential vulnerabilities in the design and function of an IPL.  In this paper, the author presents the advantages
and disadvantages of using an evergreen lifecycle approach to establish and
maintain the integrity and ?availability? of IPLs.  The author also provides recommendations to
enhance the robustness of maintaining IPL adequacy throughout the lifecycle of
the protection layer.  Specifically, the
author provides examples of IPL integrity successes through the use of an
evergreen lifecycle methodology, enhanced operational insight, and potential
pitfalls when not employing a holistic IPL lifecycle approach in maintaining
IPL integrity and adequacy.

The target audience for this paper includes project managers,
project or process engineers, EH&S managers, PSM coordinators, and
operators; however, anyone involved with small or large capital projects may
also benefit from this paper's content.