Veterans of the maintenance industry know just how important it is to make RAM analysis a part of their routine. Maintenance workers use the concepts that make it up – reliability, availability, and maintainability – on a daily basis.
RAM analysis is a main pillar of maintenance engineering. Its indicators allow us to extend equipment lifetime, prevent failures, and reduce maintenance and spare parts costs. This lets us improve the company’s productivity, profitability, and competitiveness.
Each of these indicators has a certain function; it’s crucial to know these and their respective formulas.
What is RAM Analysis?
As mentioned previously, RAM stands for reliability, availability and maintainability. To understand its full purpose, we must know its goals and benefits, as well as how it’s implemented.
The goals of RAM analysis are to:
- Decrease maintenance and operation costs
- Improve productivity
- Increase profits
RAM analysis evaluates system performance by measuring the number of failures, the time between failures, and the time to repair them, among other metrics.
It uses calculations and numbers to evaluate equipment, meaning results measured by the RAM concepts must be expressed in quantifiable terms. These depend on specific formulas and requirements.
For example, the reliability calculation corresponds to a percentage that indicates the right functioning of the equipment for a certain time. It’s usually measured in hours.
RAM analysis is a rigorous assessment that allows no false information. The registers, whether manual or digital, should always be accurate and impossible to generate wrong interpretations. Any wrong interpretations can affect the entire production chain.
More than ever, technological tools like maintenance softwares have become great allies of maintenance. They automate processes, measuring indicators in real time, all while being able to instruct the team about what should be done.
Reliability
The first letter of RAM maintenance represents the probability of the machine performing its function for a given period of time. This, which takes into account the failure rates, tells the maintenance manager how much he can trust that equipment.
Reliability is measured using a range of tools, the main two being:
- FMEA, or Failure Modes and Effects Analysis, identifies equipment damage before it actually happens, as well as its causes and consequences. It ranks failures by calculating the Risk Priority Number (RPN). This answers key questions for the maintenance plan, like what the failure is, how it happened, and how serious it is.
- Fault Tree (FT) is an organized and logical way to relate failures and their causes. By inversely reconstructing the process that led to the problem, fault tree analysis allows the manager to discover the physical, human, and latent “roots” of that fault. It’s also great at showing how well a system can withstand single or multiple failures.
- The Reliability Block Diagram (RBD) complements the Fault Tree and shows the step-by-step of the component failure. The RBD includes everything that happened between the possible causes and the problem appearing.
When it comes to asset reliability, the greatest ally of the maintenance manager is MTBF, or Mean Time Between Failures. It’s one of the most important indicators in the entire maintenance field. MTBF measures the average amount of time that repairable equipment works properly between failures, excluding any scheduled downtime.
The longer the average time of good performance, the more reliable the system is. We know this because devices are taking longer to fail. The reliability calculation is more specific, finding the probability of equipment working perfectly next week, or even next month.
Once MTBF and reliability of each item have been identified, we can schedule planned inspections and other preventive maintenance activities. The goal is to constantly improve the reliability of the plant, which is a key pillar to Reliability-Centered Maintenance (RCM). For more about the types of maintenance, check out this blog.
Think about how your team collects, calculates, and interprets the indicators mentioned above. It’s important to keep data concerning essential indicators, and to record it in the most accurate and readable way possible.
Every record you keep should be accessible to your entire team, and computer spreadsheets aren’t. You should think about replacing them with online monitoring tools, so maintainers can stay informed for entire machine life cycles.
Thanks to technological advancements, there are maintenance management and RAM softwares – like TRACTIAN – that monitor machines in real time. They calculate individual MTBF and reliability, sending insights to the manager based on these analyses.
By using this type of solution, staff can focus on more effective activities than manual data collection. It also ensures that the most important indicators for your maintenance plan are always up-to-date and error-free.
Availability
Different from both reliability and maintainability, availability is concerned with the past. It refers to the length of time that a device has been available to perform its specified functions. In other words, it’s the capacity of an asset to perform its designated role for a certain period of time.
To calculate operational availability in manufacturing, compare the available machine hours with the number of planned working hours. For planned working hours, add uptime and downtime.
The two indicators this calculation is based on are MTBF and MTTR, or Mean Time To Repair. MTTR analyzes the average time it takes for the team to repair the machine.
To estimate this time, add the repair hours and divide by the number of interventions that have been performed. Then you apply the obtained values to the formula below:
Maintainability
The last indicator is maintainability. It focuses on how easy it is to repair an asset to return it to its normal function after a failure.
Maintainability focuses on getting rid of obstacles and difficulties in technicians’ actions, and maintaining the good performance of the machine. The more difficult it is to repair equipment and return it to its proper operating state, the lower the maintainability is.
Low maintainability leads to higher maintenance costs, reduced company productivity, and more work for the maintenance and reliability team.
When MTTR is low, maintainability is high, meaning that a machine takes a short time to return to its productive state. Improving MTTR means improving both availability and maintainability of any equipment.
Maintainability analysis often takes a human evaluation to consider critical aspects for the performing maintenance team’s work, like:
- Staff access to repair and inspection spots
- The necessity of moving equipment
- Working conditions and personnel safety during repairs and inspections
- Optimized distribution of equipment eliminates lack of productivity
Removing obstacles your team faces during interventions is one of the most critical objectives of RAM analysis. And what’s more effective than choosing predictive maintenance as the star of your maintenance plan? For more on choosing the right maintenance strategy for your company, read this article we wrote.
Make RAM Analysis Yours
You’ve got a solid understanding of RAM analysis, its goals, benefits, and formulas. Now, all you have to do is apply it to your maintenance plan and watch your indicators improve.
The reliability, availability, and maintainability of your company’s equipment must be measured constantly – and rigorously. The data collected should always be accurate and impossible to be misread. Only then will it be possible to know your machinery and its maintenance, improving your processes to the highest degree.
Leave the spreadsheets behind; ensure your machines are always reliable, available, and easy to repair with TRACTIAN. Schedule a demonstration with one of our engineers to learn how you can implement our solution.
