Controlling Muri for More Sustainable Processes

Posted October 19, 2022 | Sustainability |
Process muri

It’s well known that Lean, as a process improvement and management system, originated in Toyota in the years following World War II. As Lean changed over time to accommodate knowledge work and software development, the focus has been on eliminating muda, or waste. This is generally defined as any activity the customer would not pay for (i.e., any activity that does not add customer value to the final product or service). Lean classically recognizes seven forms of waste, although some practitioners have expanded this list. Lean perceives that some muda activities must be performed but should be minimized to the greatest possible extent. Lean acknowledges two other forms of waste. One of those forms, muri (overburdening), seems like a natural fit for sustainability concerns, as unsustainable processes overburden our natural environment — but Lean has almost no tools to assess and eliminate it.


An unsustainable process is unsustainable precisely because it places more stress on the environment than it can ultimately bear, whether that’s from resource overconsumption or byproduct dumping. In contrast, a sustainable process can continue indefinitely; it is designed so the resources it uses are recycled or replenished.

If we want to incorporate sustainability into process improvement, we must develop a toolkit and integrate it with existing Lean processes and methods, such that they work together to produce the results we’re seeking.

Importantly, many practitioners believe muri is the true root cause of many other forms of waste. If we follow that line of logic, we should find a great deal of oppor­tunity for improvement by actively controlling it.

The Wastes of Muri

By examining various definitions of sustainability, we see that there are also seven wastes of muri: expediency, contamination, hazards, offloading, exhaustion, squandering, and overloading. This list may evolve over time, but it serves as a good start for people looking to make processes and products more sustainable.

Strictly speaking, the associated cost of a value stream should be considered when evaluating sustainability because overly high costs can lead to the failure of a product or enterprise. Although a category for “expense” could certainly be added, there is little risk the cost of a process will be overlooked! One thing to keep in mind, however: a process step may include more than one waste of muri. Practitioners may also find it useful to review other literature on sustainable value stream mapping.

Let’s take a closer look at the seven wastes of muri and their relation to processes and sustainability:

  1. Expediency comes as a result of short-term thinking and can be the root cause of many other wastes. Pursuing expedient solutions results in short-term “fixes” that break down over time and/or mask the real costs of a decision. Expediency reduces or eliminates careful consideration of the long-term sustainability of a product or process. Expediency results in processes that include many workarounds or short-term fixes. Expedient processes should be carefully evaluated and redesigned so they can work acceptably in the long term.

  2. Contamination occurs when toxic substances are created or released into the environment. This includes pollution, construction use, and use of products with toxic chemicals without a process in place to recapture/safely reuse the substance or neutralize its effects. Processes that cause contamination should be redesigned, and past contamination should be cleaned up.

  3. Hazards are any element of a product or process that puts personal safety at risk, whether directly or indirectly. The hazard may apply to operators involved in the work, customers, or external stakeholders. The waste of hazard means the process cannot be performed as it is without the possibility of injury or death. Processes or equipment that create hazards should either be redesigned to ensure safety or have countermeasures put in place to minimize the risk.

  4. Offloading occurs when the costs or effort required to make a process sustainable are placed on another. This can occur because the process does not include steps to replace renewable resources (such as cutting down a forest without replanting) or when attempts are made to balance the costs of an unsustainable process by purchasing tax credits or offsets. Offloading also occurs when a problem is left for future generations to clean up and resolve. Processes that offload problems onto others should be redesigned so the problem does not occur, or a countermeasure should be put in place that forces the organization to clean up the resource.

  5. Exhaustion occurs when a nonrenewable resource is used as part of a process or product. Whether the resource is plentiful or scarce, there is a limited supply of it, and each execution of the process uses some of that finite supply. Ultimately, a process that exhausts a resource cannot be sustainable. Exhaustion can be addressed by redesigning the product such that the resource is not required or by taking steps to recover the used resources through recycling.

  6. Squandering is the use of a resource beyond the minimum needed to perform the process or to produce an equivalent good. This can include overuse of materials and energy. It is critical to consider squandering in the context of equivalent goods. Processes like cryptocurrency mining and trading are similar in use to other financial instruments, but they require immense and increasing use of computing resources and power. Processes that squander resources should be redesigned to substantially reduce resource usage or be replaced with processes or products that put lower demands on the environment.

  7. Overloading is the waste that occurs when some­thing is pushed beyond its capacity on a regular basis. This includes staff overwork, excessive use of a machine beyond its maintenance cycles or tolerances, and drawing renewable resources from an ecosystem to the point where it declines or collapses. Overloading introduces risk into the process because the overloaded resource may suddenly break or become unable to sustain the demands placed on it. If a resource is overloaded, the process must be redesigned with the understanding that the resource is a constraint (Theory of Constraints may be helpful here) and the load on the resource managed to be below the level where it is at risk.

[For more from the author on this topic, see: “Can Lean Practices Save the Planet?”]

About The Author
Kevin Brennan
Kevin Brennan is an independent consultant in product management and business architecture and Professor at George Brown College, Canada. He has led organizations through strategic and business unit planning and execution, played a leadership role in enterprise change, developed and launched multiple products for a global audience, and managed a product portfolio through the entire product lifecycle. Mr. Brennan is best known for leading the… Read More