4 phases of reliability-centered lubrication
Optimize maintenance practices through assessment, design, implementation and sustainability.
By Stacy Heston, Allied Reliability
- Upgrading from the current state of lubricant maintenance to a world-class system can be achieved by means of a four-phase approach.
- Developing and implementing the program that will span the transition requires three to four weeks of in-plant effort.
- The new state of lube management requires constant monitoring and continuous improvement to accommodate changes in equipment, personnel, and technology.
It’s common to see plants focus continuous-improvement efforts on maintenance initiatives. There’s a desire to implement additional condition monitoring technologies or expand existing coverage levels to better understand when equipment is developing problems. Those same plants emphasize wanting to do the right thing from a precision maintenance standpoint. However, they rarely consider basic asset care or lubrication needs in conjunction with other improvement initiatives.
This is unfortunate because the applied maintenance strategies aren’t as effective as stand-alone initiatives. Lubrication is comparable to the life blood of an asset. The way to achieve the highest return on a maintenance investment is to incorporate reliability-centered lubrication (RCL) along with the reliability maintenance initiatives.
Like reliability-centered maintenance, RCL is a logical way to identify which equipment needs to be maintained on a condition-monitoring and preventive-maintenance basis rather than a let-it-fail-and-then-fix-it basis, commonly referred to as a run-to-failure (RTF) maintenance strategy. The RCL program optimizes lubrication maintenance practices by:
- designing the applied tasks based on engineered applications specific to component attributes and operational and environmental considerations
- standardizing component modifications to ease the burden of completing basic lubrication tasks
- maximizing the required task intervals for a component
- optimizing the number of correct lubricants on site
- quantifying component health based on observational and trended data.
The RCL program development involves a phased sequence of tasks that ensure the program developed is a sound one that meets plant needs.
Phase I — Current State
The first phase of the RCL program development consists of a benchmarking exercise referred to as a current state analysis or assessment. This exercise identifies gaps between where a plant currently operates and a world-class program or industry best practices. During the assessment, an outside consultant makes a three-day site visit to focus on the nine categories of an RCL program:
- work management
- work execution
- quality assurance/quality control
- program management
- lubrication hardware
- materials management
- human resources
- health, safety, and environment
In addition to examining these actors, the consultant compiles a specific review of:
- current lubricant selections and methods used to determine them
- contamination control practices
- grease lubrication/applications
- oil lubrication/applications
- routine inspections
- oil sampling methods
- oil sample test slates
- lubricant storage and handling
- metrics tracking.
With the relevant data in hand, the program consultant works with plant personnel to discuss program gaps and determine an overall plan for further development. The assessment process allows every stakeholder to see where the program design phase should focus. Phase I might also include developing program goals, a mission statement, and a program charter.
Phase II — Program Design
This phase entails a variety of tasks that are based on the information gathered during the assessment. Entering into Phase II implies a full commitment from plant personnel to work in partnership with the consultant to develop a program that meets the objectives outlined in Phase I. The tasks in Phase II are designed to meet the Phase I objectives, goals, and program charter. The full process, at a minimum, includes no less than seven aspects.
Walk down: The walkdown is a physical survey of lubricated assets in the plant that meet the criteria for lubricated assets as defined in the project scope. These assets generally have a minimum of one lubricated component or lubrication point that requires grease, oil, or hydraulic fluid. Information is gathered directly from the component, including manufacturer, model number, sump volume, operating speed and conditions, and component modifications. In some cases, research might be required to gather additional pertinent information to be used during the lubrication design task to determine the required steps for best-practice lubrication and associated procedures.
Engineered lubrication design: The lubrication design task uses industry-accepted formulae to calculate specific requirements for required lubricants, quantities, and intervals based on data collected during the walkdown. This task leads to the basic design of the lubrication program.
Lubricant requirements: Information on the currently used lubricants is collected during the walkdown. Characteristics of the current lubricants are compared to the required and engineered characteristics to ensure proper lubrication product types and qualities are in place. These properties include the basic lubricant type, viscosity, additive packages, base-oil type, and grease-thickener type.
Grease quantities and intervals: Quantities for grease-lubricated bearings and other grease points are determined using an industry-accepted formula. Research shows that filling a bearing to about one-third of capacity is optimum for controlling a bearing’s operating temperature (Figure 1). Regardless of contamination levels, water exposure, or operating speed, the one-third-volume grease pack is optimal volume.
Figure 1. A bearing’s operating temperature is a function of the quantity of grease used in it. The optimum amount of grease is about one-third of the total volume available in the bearing.