Establishing Integrity Operating Windows (IOWs) for Refinery Fired Heaters

Introduction

Understanding and establishing effective Integrity Operating Windows (IOWs) is critical in the operation of refinery fired heaters. IOWs, as described by API 584, are a specific subset of operating limits focused on maintaining the integrity and reliability of process equipment. IOWs address issues involving process parameters that, when not adequately monitored or controlled, can impact the likelihood and rates of damage mechanisms, potentially leading to loss of containment.

The establishment, implementation, and maintenance of IOWs require a multidisciplinary approach and should be considered an essential part of a facility’s operation and maintenance strategies. This article provides an overview of the key components in establishing IOWs, the levels of IOW limits, and the basic principles and application of API Recommended Practice 584 to achieve reliable fired heater performance.

IOWs – What's the Big Deal?

IOWs are the limits within which fired heaters should operate to maintain safe and productive operation. According to API 584, IOWs are “a vital component of integrity management,” and should be implemented “for the express purpose of avoiding unexpected equipment degradation that could lead to loss of containment.” [1] Essentially, IOWs offer an operator considerable peace of mind in the condition of their assets, as long as they are operating within determined parameters.