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Calculating Workshop Capacity Requirements

Download a simple tool to estimate your workshop bay requirements. 

Author: Peter Lee 

Over the years, Bluefield has conducted multiple workshop and infrastructure studies. One of the most common studies is workshop capacity assessments to determine the workshop bay requirements for clients. While every site is different, there are a few guides and considerations that can be commonly applied. For example, using a ratio of 6 to 8 equipment per bay is a common first pass rule of thumb to estimate approximately the number of workshop bays required.   

Although this is a great first pass rule of thumb, we find equipment availability plays a significant factor on the number of bays required. The lower the equipment availability, the higher the demand for workshop space to carry out maintenance. Utilising this method allows us to calculate bay requirements by comparing available bay hours against maintenance hours required by the fleet.  Again, while this is not a perfect calculation, it will get you a little closer to the required bays. The table below shows the impact availability has on bay requirements as the fleet size increases based on a few assumptions.   

 Table

While you can easily match equipment maintenance hours to available workshop bay hours, this is an over-simplified model that does not reflect the realities of maintenance when required maintenance hours match workshop bay hours. Although it is not uncommon to expect that the majority of maintenance should be planned to match workshop space available, unplanned activities often cause shortages of available workshop bays. For these cases applying a Queuing Theory model helps understand the potential impact. 

It is important to note the above has only looked at total number of bays required. In reality, there are multiple bay types commonly utilised. These include: 

  • Service bays 
  • Tyre bays  
  • Weld bays 
  • General maintenance bays (typically includes Planned Component Replacement activities) 
  • Wash bays 

To understand individual bay requirements, time is taken to come up with a reasonable set of assumptions as to where maintenance time is spent. To do this we work with the client to determine reasonable estimates around the following key areas: 

  • Repair time in field  
  • Servicing schedule 
  • General tyre strategy 
  • Welding requirements 
  • Wash Bay 

Repair time in field – This is often not known by site; however, a reasonable estimate can be calculated by reviewing the Time Usage Model data focusing on Unscheduled maintenance. Using an assumption on maintenance completed in field (e.g. unscheduled events under 3 hours), a reasonable estimate can be achieved.   

Servicing schedule – This is a simple combination of the service interval and average service time to calculate the yearly servicing demand per piece of equipment. 

General tyre strategy  We apply a tyre change strategy to calculate the tyre bay demand and add an allowance for unscheduled tyre changes based on site history.   

Welding requirements – Where required, an estimated equipment weld strategy involving frequency and duration is agreed. 

Wash bay requirements – To calculate wash bay requirements, bay capacity must be considered differently to a general workshop. This is due to the peak demands typically experienced at the end and start of shift readying equipment for services. Thus, bay availability should only be considered as the peak times and the demand is based on the number of services per year by an average equipment wash duration. 

Collating these inputs allows us to assume the remaining maintenance downtime is attributed to the general repair and planned component replacements. The individual workshop bay demand assumptions should be applied against the full equipment fleet to finalise the makeup of workshop bay requirements.   

We’ve built a simple tool that helps us produce first-pass estimates for workshop bay capacity. Feel free to download and use it, and we’re always happy to hear feedback on how we can improve it. 

 

Peter has previously written articles on planning and forecasting mobile equipment plans and requirements. Read them here. 

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