Knowing how critical every piece of equipment is at your plant will help you identify potential bottlenecks. These are the highly critical assets on which the entire production depends and if they break down production stops or bottlenecks occur. Equipment criticality assessment analysis in industrial maintenance can help you identify these pieces of equipment and support you in the creation and deployment of successful preventive and predictive maintenance strategies.
Bottlenecks in Industrial Maintenance
Bottlenecks in a manufacturing process occur when a key asset is unable to reliably produce the required output. The goal of industrial maintenance is to categorize your piece of equipment according to its importance in order to mitigate the negative effects and help you cope with the problem. Assessing the criticality of your assets will help you identify the equipment that should be observed the most.
Moreover, evaluating the criticality of assets contributes to improved spare parts management.
Create your equipment sheets in the maintenance management app Mobility Work in order to trigger tasks and activities
Why Is It Important to Identify Bottleneck Equipment?
Each manufacturing process is composed of equipment of different criticality, but they are not always well identified. A bottleneck machine could be defined as a critical piece of equipment of your production unit, a vital element of your production tool which requires particular surveillance. This asset affects the overall output the most by usually using the highest percentage of its capacity.
If this machine doesn’t have enough capacity, breaks down frequently or has an operator who needs training, the entire production line will get stuck. And the situation can get even more complex with several bottlenecks at different process steps. In this case, you should know which machine has the highest priority.
Mismanagement of these assets can result in dramatic consequences for your business, including a complete shutdown of your production system and unhappy customers.
The PIEU Method Helps You Prioritize Company’s Assets
The PIEU method is a fairly well-known method in industrial maintenance for determining the level of criticality of your equipment. It was developed by the French engineer Lavina to prioritize the company’s assets. In order to calculate the criticality of your equipment, you have to determine the value of the following letters for each machine.
P – fr. pannes / en. failures; P corresponds to the machine’s failure index
I – fr. importance de l’équipement, / en. the importance of the equipment; I stays for the machine’s importance rate
E – fr. état de l’équipement / en. the condition of the equipment; E describes the condition of the asset
U – fr. utilisation / en. the using rate; U is the use rate.
The failure index (P), the importance of the equipment (I), the condition of the equipment (E) and the use rate (U) are the four criticality indexes which can be contributed to different groups of assets and thus classify the equipment in several sets.
Consequently, criticality assessment is performed according to the following criteria.
| Weight | |||||
| Criteria | 0.01 | 1 | 2 | 3 | |
| P – Incidence of failures | Serious consequences | Impact on quality and waste generation | Possible repairs | No impact on quality | |
| I – Importance of equipment |
Strategic, no load-shedding on other equipment, subcontracting impossible |
Important, no load-shedding, subcontracting possible |
Secondary, load-shedding possible | Emergency equipment | |
| E – Condition of Equipment | To be fixed | To be revised | To be observed | Specified Equipment | |
|
U – Equipment use rate |
Saturated | High | Medium | Low |
Once the different elements have been determined, you only need to calculate the criticality of the machine according to the following formula:
Criticality of your equipment = P*I*E*U
Then you just need to classify your critical equipment following this rule:
Pieu < 1: very critical
1 < Pieu < 10: moderately critical
Pieu > 10: less critical
Pieu methods : Examples
The table below shows some examples of criticality on a melting production line at a foundry:
|
Incidence of failures |
Importance of equipment | Condition |
Use |
Criticality | |
| Cupola Küttner | 0,01 | 0,01 | 3 | 2 | 0,0006 |
| Cooling tower Küttner | 0,01 | 0,01 | 3 | 2 | |
| Filter Lürh | 0,01 | 0,01 | 2 | 2 | 0,0004 |
| ADC Loading bridge | 1 | 0,01 | 3 | 2 | 0,06 |
| Küttner Recovery tower | 0,01 | 0,01 | 3 | 2 | 0,0006 |
| Shovel Fuchs Terex MHL340 | 3 | 2 | 1 | 3 | 18 |
| Bucket granulator | 1 | 1 | 3 | 1 | 3 |
| Conveyer | 3 | 0,01 | 3 | 1 | 0,09 |
| Bracket SAS | 2 | 2 | 3 | 3 | 36 |
How to Identify the Critical Equipment and Bottlenecks?
Once you have completed the PIEU method for all your processes, you have determined all of your critical equipment. The next steps will be to identify it in your CMMS software.
Mobility Work CMMS is provided with an analytic tool to help you analyze all your maintenance data and adapt your strategy
To do this, simply use the tag or label function present in CMMS Mobility Work application. You can create different types of equipment families via the tags. Here are some examples of possible tags:
Category A – Bottlenecks or very critical equipment
Category B – Equipment that should be regularly observed
Category C – Equipment that is not very important
Equipment criticality assessment methods as the PIEU method can help you identify and integrate relevant adjustments to your maintenance strategy. By prioritizing equipment, bottlenecks in industrial maintenance can be successfully prevented and reliability improved.
