Originally published in the August 2012 issue of Pumps & Systems.
Increasing the mean time between repair (MTBR) is a universal goal for pump end users. While statistics vary, a reasonable pump MTBR goal for a refinery following best practices is about 5 years. The average time between repairs for chemical plants is typically a bit lower. With the right maintenance plan in place, end users may be able to boost their own MTBR figures.
To achieve that goal, many end users turn to pump reliability programs, which offer a multitude of benefits. In addition to reducing maintenance frequency and costs through increased MTBR, an effective pump reliability program creates a safer environment for workers by eliminating potentially hazardous operating conditions. When equipment is running smoothly, end users can also achieve uptime faster, resulting in more throughput and increased productivity. Here are some tips on how to create a successful pump reliability program.
Establish a Plant-Wide Pump Reliability Team
A pump reliability team should include a mix of plant employees and representatives from equipment vendors. For the program to be successful, it should be a partnership, with all participants open to recommendations from other members. End users’ maintenance or reliability teams typically run pump reliability programs and provide technical background as needed.
The team should also include operations employees who can learn about operating activities that undermine reliability from maintenance team members. They can inform the team of any operating problems. In addition, involve procurement employees who can work with vendors to optimize inventory levels of maintenance-related parts, resulting in savings. Once the reliability team is assembled, members should determine the key performance indicators that will be used to measure the program’s success and establish a regular schedule of reviews to verify the program’s progress.
Set Up an Equipment Reliability Database
Recording all pump-related information in a central location makes spotting trends and recurring equipment issues easier. Many vendors offer proprietary database programs to help monitor pump reliability, or end users can establish their own databases.
The database should include service descriptions, the repair history and a maintenance checklist for each piece of equipment. It should also generate reports. Regular report generation will help identify the “bad actors” in the plant, and information from the database can be used to capture detailed failure analyses and develop improvement plans.
Only a limited number of people should be allowed to input program data. The information included in the database should be as relevant as possible. End users may want to give some users editing access and others read-only access.
Follow Pump-Specific Best Practices
End users should keep these best practices for pumps in mind to maximize the program’s effectiveness:
- Obtain up-to-date pump drawings and performance curves so maintenance and operations employees have accurate references.
- Follow American Petroleum Institute (API) 610 pump specifications. Buying, operating and maintaining pumps to current API standards—such as using large-bore seal chambers—allows end users to use the latest and best seal designs with their equipment. This is an important part of maintaining pump reliability.
- Review the indicator readings on pumps regularly. End users should aim to check their pumps once per week and monitor critical or low-reliability pumps multiple times each day.
- Use nonlubricated couplings. Unlike lubricated ones, these couplings do not require regular maintenance. This means maintenance personnel have one less thing to worry about.
- Convert any packing in systems to seals.
- Reduce the use of cooling water. End users typically use cooling water to cool the bearing oil, the mechanical seal flush or the buffer or barrier fluid. They may also use it to provide a quench for seals. However, using cooling water to cool bearing oil or the seal chamber is usually not effective and can cause other problems—such as water migration into the bearing housing. While a cool flush can benefit a system, cooling water use can be avoided by choosing a seal that operates satisfactorily at the pumping temperature. Not only can using less cooling water cut water circulation and treatment costs, it can also improve seal and bearing life, since uneven cooling can produce distortions and misalignments in the pump case.
- Institute standard repair procedures and ensure that all maintenance personnel follow them.
Make Sealing System Best Practices Part of the Plan
Sealing systems are a critical part of pump reliability. These best practices can help to keep everything running smoothly.
- Obtain up-to-date, application-specific layout drawings for your sealing systems.
- Buy, operate and maintain seals to API 682 specifications to ensure compatibility with the rest of the equipment. A member of the reliability group should monitor API specifications and update equipment as standards change. Current standards include replacing component seals with cartridge seals, which should be air pressure tested per API specifications to ensure proper assembly.
- Evaluate the sealing system and how it is installed, and review proper maintenance procedures to ensure that they are appropriate for the equipment. Things to consider include the buffer or barrier fluid system, if using a dual seal arrangement, and whether wet contacting or dry noncontacting seals are appropriate. Make sure to review the piping arrangement to ensure that it is properly installed, since improper piping inhibits the seal system’s life.
- Minimize the number of seal types, arrangements and systems in the equipment. This slashes inventory costs by reducing the number of parts needed on hand, and it reduces the number of procedures that mechanics and operators must learn, reducing the potential for errors.
- Understand the environmental regulations in the area and the capabilities of the installed base of mechanical seals. EPA leak detection and repair (LDAR) requirements mandate that if a mechanical seal is leaking at a higher-than-approved rate, the pump must be shut down and the problem repaired within the prescribed time frame.
Review Appropriate Bearing and Lubrication Practices
Keeping bearings properly lubricated extends their life and boosts overall equipment reliability. End users should review their equipment manufacturer’s specifications and follow the recommended guidelines for maintaining bearings properly. For example, many manufacturers recommend using bearing isolators to protect bearing housings from water and dirt, which can hinder their performance.
Make Education a Priority
Whether lunch-and-learn sessions or online training, ongoing education should be a critical component of a pump reliability program. For operations employees, focus on proper startup procedures—such as ensuring that all appropriate valves are open—to avoid early failure while commissioning equipment. For maintenance personnel, teach proper seal installation techniques and the basics of maintaining mechanical seals. Other relevant educational topics include shut-down procedures, bearings and lubrication.
Review the Program Regularly
A pump reliability group should meet regularly to discuss its progress and whether the program is meeting its pre-established, critical performance indicators. Consider holding monthly status meetings with key team members to review data on a micro level and quarterly or semiannual meetings with the entire team to make strategic decisions about the program. Some end users may need more frequent meetings when the program is first launched. Then they may decide to scale back meetings once results are realized.
While creating a pump reliability program requires time and effort, the payoff can be significant. End users who focus on improving reliability through established best practices reap the benefits of reduced labor hours, reduced maintenance costs and increased safety and productivity.