Solving the Mysteries of Critical Check Valves

Introduction

In the author’s experience conducting more than sixty American Petroleum Institute (API) Process Safety Site Assessment Program (PSSAP) assessments, critical check valve (CCV) inspection programs are one of the lowest scoring of all of the fixed-equipment mechanical integrity (MI) categories that are assessed. In fact, where a score of 75% meets expectations, CCV inspection programs score 42% on average. In an effort to help the industry improve CCV programs, this article discusses important aspects of a CCV MI program. Specifically, this article will discuss the what, why, where, how, when and who of CCVs, such as:

• What criteria designates a check valve as critical?
• Why is a CCV inspection program so important?
• Where are CCVs found in process units?
• How should CCVs be inspected?
• When should CCVs be inspected?
• Who should inspect CCVs?

The answers to these questions and others should be of major importance to personnel involved in facility fixed equipment MI programs. The top five most commonly given reasons sites have not implemented a CCV program are listed below.

1. “We are going to get around to it, but there is so much other stuff going on that we just haven’t had time to implement a CCV program.”
2. “We are waiting on the process safety management department to provide us with a list of CCVs.”
3. “We don’t have any CCVs because we are not allowed to take credit for them as a safeguard in a process hazard analysis (PHA) or as an independent protection layer (IPL) in a layer of protective analysis (LOPA), so therefore we have been told that we are not allowed to have CCVs.”
4. “Is CCV inspection a ‘should’ or a ‘shall’ in API 570?”
5. “I thought someone else was responsible for the CCV program.”

Do any of these sound familiar to you?