Many plants set aside one time in the year when testing, repair, and replacement of most valves and related equipment takes place. This work involves considerable preparation, a thorough inspection and documentation of systems and components, diverting or hiring manpower for the job, progress reports and follow-ups, and a considerable amount of time and money.
Companies need to plan effectively for this to make sure everything runs smoothly, especially since much of the work may involve special tools and equipment, temporary outages as valves and systems are replaced, shared repair equipment and resources, and outside contractors for expertise in specialized areas.
A white paper developed by Spirax Sarco, of Blythewood, S.C., details the procedures companies should follow to assure that this maintenance is timely and cost-effective. Spirax Sarco specializes in valves, engineered products, repair and maintenance, and other equipment and services for steam installations. Nevertheless, the white paper, titled "Valve Maintenance: Preparing for the Plant Outage," is a useful guide for all companies when they perform maintenance on operations, make upgrades, or check current practices against those recommended by the paper's author, David Matherly, product manager of controls and instrumentation at Spirax Sarco.
The most important preparation, Matherly wrote, is planning. Work dates and potential outages need to be determined well in advance and agreed to by relevant departments such as maintenance and operations. A team that will oversee the project and a designated leader need to be appointed. An initial walk-through of the work areas is necessary to size up the extent of the operation. The amount of work required in each area will be evident in the condition of valves and actuators, flange connections, stem seals, packing, and other components.
Documenting problems is critical to assure they are fixed, to be certain that work progresses smoothly, and to make sure that necessary tools and repair equipment are properly located. "The more quickly ... valve technicians move from valve to valve while keeping equipment and tool relocation distances to a minimum [will greatly improve efficiency," Matherly noted.
All valve-related data should have been stored in a computerized maintenance management system (CMMS) or other relational database when equipment was installed. This information needs to be updated during the walk-through, and it needs to be revised after maintenance is completed. Maintaining detailed records of equipment during installation and maintenance is essential to accurate record-keeping.
Matherly said the team needs to identify special equipment in need of repair or replacement. Some types of valves, actuators, and components might have long production lead times - up to six months, in some cases - and thus need to be ordered as far in advance of the work as possible to avoid delays in the project.
Companies also have to determine if they have enough inventory on hand for the work, or if they have to order more. This also takes time, since quotes need to be reviewed, purchase orders placed, and deliveries received.
Matherly added that if outside contractors are used, this introduces another variable in scheduling and cost, which must be planned and budgeted for well in advance.
Regular meetings are necessary by the team overseeing the work before and during the operation. If a contractor is used, a representative should attend these meetings. Among issues to be settled: the scope of work needs to be defined and finalized; valve and other equipment work needs to be prioritized and a repair schedule established; and a budget review has to be conducted, ideally with input from the contractor.
Of importance, Matherly recommended that a "scope creep budget" be established to handle the cost of additional repairs that become evident during work.
Other issues to take up include work logistics. These range from basic concerns such as the availability of power for tools, I/O loop power, and controller/DCS signal active controllers for loop checking to compressed air and valve maintenance manuals. Cranes, rigging, man-lifts, forklifts, and safety harnesses need to be on hand, along with special tools for valve disassembly or setting and test equipment to make sure everything works.
One important point for project members to discuss is ancillary upgrades to electrical systems, process piping, control logic, and utilities that are either necessary or convenient to do as work progresses.
As noted, before-and-after documentation is critical, both for work updates and for future operations. Matherly advised that "as found, as repaired, and as left" descriptions and photos be entered in a CMMS database, daily status reports be released by a contractor, and a post-report be produced to summarize the work done and provide an accurate account of the repair parts, inventory ordered, and purchase orders executed. This last item is especially important for precise cost analysis by the sourcing or procurement department.
The white paper can be downloaded at www.flowcontrolnetwork.com.
Annual plant-wide maintenance operations to repair and replace valves and other equipment can be delayed and run over budget if not thoroughly planned. Credit: BASF