Damage Management Locations (DMLs) – Connecting Inspection Data with Asset Lifecycle Management

Introduction

Owner-users of pressurized equipment, including pressure vessels, piping, and tanks, are becoming increasingly interested in the lifecycle management (LCM) of equipment to enhance reliability and availability [1]. At the equipment design stage, the LCM process requires identification of potential damage mechanisms and proper materials selection to resist or mitigate the damage. After the equipment has been commissioned, the LCM process continues with the use of prescriptive or risk-based inspection (RBI). An evaluation of the in-service inspection results reveals whether any damage that may have occurred is anticipated (i.e., was considered in the initial design) or unanticipated. If unanticipated damage is discovered, the LCM process requires identification of the damage mechanism and a subsequent fitness-for-service (FFS) assessment to facilitate a decision to run, repair, or replace the damaged components. If a run decision is made, inspection data and remaining life calculations for the damaged location, evaluated using FFS technology, need to be managed together with condition monitoring location (CML)-based inspection data for the circuit containing the damaged component. A convenient way to manage damaged components is to introduce the concept of a damage management location (DML) where inspection data and FFS assessment results, including an estimate of the remaining life, are stored and readily accessible to the inspector. These data, together with remaining life estimates from CML data, offer a complete view of the components within the inspection circuit for inspection planning.

Asset Lifecycle Management – A Review

The overall LCM process for fixed pressurized equipment in the refining and petrochemical industry is shown in Figure 1. The LCM process for fixed pressurized equipment involves five important components: damage mechanism identification, construction codes and standards, in-service inspection codes, FFS codes, and repair guidelines. Technology integration between these codes and standards is necessary for a successful LCM process for fixed equipment because similar technologies are utilized for both design and in-service assessments.