What is Asset Availability?
Asset availability, often referred to as equipment availability, is a critical metric that assesses whether machines or systems are operating satisfactorily at any given time. It is particularly relevant for repairable and continuously operating equipment, aiming to minimize downtime and optimize on-time performance.
Various stakeholders, from design engineers to equipment operators and maintainers, are invested in improving equipment availability, recognizing its significant impact on overall productivity and profitability.
TL;DR
Asset Availability measures whether equipment is operating as expected and is crucial for minimizing downtime and optimizing performance.
Calculated using different methods, including considering potential production time, actual production time, and repair time.
Inherent Availability and Achieved Availability offer insights into equipment design and maintenance impact.
Improving asset availability involves proactive maintenance, fault tolerance in design, and customized maintenance programs, leading to cost savings and increased productivity.
The Significance of Asset Availability
Asset availability is of paramount importance for several reasons:
- Downtime Reduction: High asset availability minimizes unplanned downtime, ensuring that equipment is consistently operational. This leads to increased production efficiency and reduced production losses.
- Optimized Resource Allocation: Improved asset availability allows organizations to allocate resources effectively. When equipment is running smoothly, there is less need for emergency repairs and costly reactive maintenance.
- Enhanced Predictability: Reliable equipment availability enables better production planning and scheduling. Organizations can meet customer demands more consistently and avoid production delays.
- Cost Savings: Reduced downtime and efficient resource utilization result in cost savings. This includes lower maintenance expenses, decreased overtime labor costs, and decreased production losses due to equipment failures.
Asset Availability Calculation Methods
Potential Production Time, Production Time, and Repair Time Method:
Asset availability is calculated by considering three factors:
- Potential Production Time: This is the total time during which the equipment was expected to run, excluding delays unrelated to equipment issues.
- Production Time: The actual time the equipment operated without breakdowns.
- Repair Time: The duration during which the equipment was not running due to unexpected malfunctions and subsequent repairs.
The formula for asset availability, expressed as a percentage, is:
Availability = (Production Time/Potential Production Time) × 100
For example, if the potential production time is 170 hours, and the equipment experienced 20 hours of downtime due to a breakdown, resulting in 150 hours of actual production time:
Availability = (150 hours/170 hours) × 100 = 88%
Asset Availability Based on Uptime and Downtime (Achieved Asset Availability):
Also known as achieved asset availability, this method focuses on uptime (the time equipment is operational) and downtime (the time equipment is broken down or under repair). Potential production time is considered the sum of uptime and downtime.
The asset availability formula using uptime and downtime is as follows:
Availability = (Uptime/Uptime + Downtime) × 100
Here, uptime is generally defined as the time equipment is running, and downtime is the time it is out of operation due to breakdowns or repairs.
Inherent Asset Availability Calculation:
Inherent availability is often used by machine designers and original equipment manufacturers (OEMs) during the machine design phase. It is represented by the following equation:
Inherent Availability = MTBF/MTBF + MTTR
- MTBF (Mean Time Between Failure): This metric calculates the average amount of time equipment runs before failing.
- MTTR (Mean Time to Repair): It calculates the average amount of time it takes to make a repair, considering only corrective downtime.
In this formula, MTBF and MTTR are used to estimate inherent availability, which represents the availability performance based on design and inherent characteristics of the machine. It measures how quickly the asset can return to operation after a failure.
Improving Asset Availability
Enhancing asset availability requires a multifaceted approach that spans the entire asset lifecycle:
- Incorporate Fault Tolerance in Design: Design engineers can improve inherent availability by designing machines with greater fault tolerance, such as incorporating redundancy. This increases reliability and extends the Mean Time Between Failure (MTBF), leading to better availability.
- Customize Maintenance Programs: Organizations should develop maintenance programs tailored to each asset’s specific needs rather than relying solely on OEM-provided schedules. Regular program improvements based on machine health and performance can prevent over-maintenance and under-maintenance.
- Proactive Maintenance: Transitioning from reactive to proactive maintenance strategies helps prevent unplanned downtime events. Proactive maintenance identifies potential issues early, reducing the likelihood of unexpected failures.
- Root Cause Analysis (RCA): Implementing RCA practices allows organizations to identify the root causes of breakdowns and develop data-driven preventive maintenance strategies. It enhances troubleshooting and minimizes repair time.
