When an industrial valve requires replacement , the amount of work involved in planning and executing the task varies enormously depending on the industry . Since replacing valves often requires complete – or at least partial – shutdown of the plant , companies try to schedule this type of task in a turnaround .

However , this is not always possible . This article will explore how maintenance works in large plants and the typical steps that are involved in planning a valve replacement .

By Davi Sampaio Correia , Technical Consultant

Introduction

Refineries , petrochemical plants , and production platforms can easily have thousands of check , manual , and actuated valves . As they handle flammable and / or toxic products , safe interventions on piping require complete – or at least partial – shutdown of the plant . That makes the cost of replacing a valve less about the task itself - planning the work , procuring materials , mobilizing a team – and more about forfeited revenue . When possible , maintenance tasks are scheduled to occur during a turnaround , which is a scheduled outage that lasts somewhere from 2 to 4 weeks , and it is planned more than a year in advance . Turnarounds often require a project management approach and the use of sophisticated software tools , as they involve the coordination of thousands of resources during their critical days . This article does not deal with the extra layer of complexity of integrating valverelated tasks in a turnaround schedule . Instead , it focuses on some common individual components that comprise the breakdown list of tasks required to replace a valve . Before getting into these tasks , it is worth exploring how maintenance requests are evaluated and planned .

How maintenance works in complex plants

Maintenance can be done at four different states of the plant ’ s operation : on an up-andrunning plant , during a partial shutdown , complete shutdowns , or during turnarounds . For valves , it all depends on the system they are on . Can it be bypassed to allow valve replacement ? Can the maintenance personnel safely prevent line pressure from reaching the valve being replaced ? Management , along with safety , process , and maintenance teams are constantly evaluating if a plant should be shut down to allow valve replacement or if the task can be postponed till the next turnaround . Regardless of when it is happening , maintenance tasks need to be integrated within a company ’ s natural workflow . It is not beneficial for the maintenance crew to show up to remove a valve during a crucial test of the plant led by the process team ; or to replace a valve with the same model when there is a study in progress to change the type . The maintenance department must coordinate efforts with several other departments - such as process , instrumentation , and safety - to avoid rework , and optimize tasks . Companies often use specialized maintenance software to accomplish this . For example , SAP R / 3 PM module

a ) Valve installation .

b ) Dealing with instrumentation .

Figure 1 : Challenges in valve maintenance . Sources : a ) http :// ropeline . com . br / portfolio / manutencao-de-valvulas / b ) https :// www . ceasefire . in / copy-of-corridors-socity .

( Plant Maintenance ) is one of many softwares that can be used to plan maintenance . However , some plant interventions may be considered on another system before becoming part of the SAP R / 3 environment . For example , Management of Change ( MOC ). Management of Change ( MOC ) is a process companies use to assess and control change before it happens . The main goal is to minimize the risk of unforeseen consequences . In the case of valve maintenance , there could be an ongoing study related to a MOC request to change the valve type – from gate to ball , for example . By checking the MOC database before going ahead with a maintenance task , a company ensures that it is not wasting resources by replacing a valve that might need to be replaced again in the short term . A Maintenance Planner ( MP ) is the professional within the maintenance structure responsible for harmonizing maintenance strategies with the strategies carried out by the other organizational structures of the plant . In this role , the MP is also responsible for ‘ planning the work and working the plan ’. That entails : 1 : Defining the scope – In the case of replacing a valve , the MP might add related tasks to be performed by the same crew while they are at the location ( replace a nearby pressure gauge , for example ). A scope of work document is made with complete valve identification ( tag , pictures , drawings such as isometrics and P & IDs ).