The Tap, the Car and the Teacup

A multi-’fauceted’ analogy of LEAN process improvement.

The Tap, the Car and the Teacup

A multi-’fauceted’ analogy of LEAN process improvement.

What  is ‘LEAN’ process improvement? How does the LEAN way improve processes?  To gain an understanding, it’s best to start literally.

Here’s a dictionary definition:

lean (lēn): thin, especially healthily so; having no superfluous fat.

From a process perspective, ‘superfluous fat’ can be understood as inefficiency.

When  a process consists of just one person doing one activity with all the  required resources, things are simple. However, when we start to add  more steps and more people into it, things become more complicated.

Efficient  processes co-ordinate various resources, in the best possible sequence,  to deliver a product or service. Inefficient processes are bloated with  wasteful operating practices. That waste builds up over time.

But there’s no need to go into complicated examples. Instead, let’s start by making tea.

Making  a cup of tea for yourself is simple enough. Making tea for 10 guests is  slightly more involved. If one of these guests offers to help you,  it’ll reduce the time taken but also it’ll also need more coordination.

Now,  imagine if you had to make tea for 5000 guests! It gets still more  complicated. You’d have to plan on a larger scale. You’d have to  coordinate delivery of supplies, hire servers, and — worse still —  figure out how many people you need to serve and what kind of tea they  like.

The  more things we need to co-ordinate, the more chances we have of  breakdowns. And when processes get more complicated, that’s when  inefficiencies creep in. These inefficiencies waste time, which in turn  waste money, which in turn reduces profits and customer satisfaction.

LEAN helps us remove these inefficiencies from a process.

It was against this backdrop that Taichii Ohno,  along with other engineers at Toyota, began introducing new techniques.  Techniques designed to improve productivity, while maintaining quality.  The Toyota engineers did this with cars, not tea — but now, their  methods have been used for many other types of manufacturing as well.

Traditional  manufacturing, which relied on economies of scale, produced a lot of  waste. That was either obvious waste — imagine heaps of scrap metal — or  hidden waste, like holding high levels of inventory items. LEAN  manufacturing techniques began systematically identifying and reducing  wasteful operating practices.

The engineers at Toyota took a good look at the current manufacturing practices, and re-designed them to achieve a fundamental shift in thinking: from utilization of machines, to flow of product through the total process.

Ohno is considered the father of the Toyota Production System,  which is basically a framework for conserving resources while reducing  waste. The Toyota Production System achieved considerable and  sustainable manufacturing success, and it became the precursor of LEAN manufacturing: a set of principles designed to add value by removing things that don’t add value.

If something can be done in one step, LEAN tries not to do it in three.

LEAN  concepts are now commonly used across service industries as well. The  concepts have been so pervasive that they’ve almost become common sense.

There  is an abundance of literature on LEAN. Many people have written about  it. Many people have read about it. Despite this, I often feel the  fundamentals are not grasped solidly.

LEAN  is often misunderstood. People either view it as a “cost-cutting”  methodology, or as something that only applies to manufacturing. True to  its roots in quality management, LEAN is actually a mindsetof continuous improvement, in the pursuit of perfection. It’s about always trying to make the process better.

LEAN  revolves around three fundamental concepts: ‘flow’, ‘pull’ and ‘value’.  It provides a set of techniques, to help manufacturers and  service-providers achieve the ideal outcomes—  delivering what customers want , when they want it— while still keeping  costs low, and having high flexibility and quality and fast turnaround  times.

Observing  the hot water tap allowed these concepts to sink in for me — in a  meaningful, practical, and memorable way. I present key LEAN concepts  below using the analogy of the hot water tap.


LEAN is all about flow.  In the optimum flow, work progresses across a process smoothly and  swiftly. In manufacturing, this is not always easy, since different raw  materials are processed by various machines, people and processes.

Taps  are also about flow. In our case, hot water flows through a tap, at a  set rate, at our command. When the tap is working, all is well. People  barely notice its existence. However, consider the following scenarios:

  • Dribs  and drabs — sometimes, at the start of the day — or perhaps during  lunch times when the burden on the system is highest — flow is  interrupted.
  • Long  time for hot water to come — which can, among other things, be a  consequence of plumbing design. This is often seen in homes where one  geyser supplies the entire house. When hot water has to travel through  longer pipes twisting all the way round a building, then it’ll take  longer time to arrive at the tap..

The above are symptoms of the three classic enemies of LEAN: Waste (Muda), Overburden (Muri) and Unevenness (Mura).

We  have often heard the mnemonic TIMWOOD, which talks about the classic  wastes in processes. However, we don’t hear that much about ‘burden’  (and overburden) or ‘variation’ (and unevenness), which I feel is  equally important to be aware about.

Maximising  flow is about ensuring that the process is efficient and effective.  Flow of material — or any other work item — through the process must be  smooth andswift. Waste, variation and overburden impede flow.

This  is similar to a common plumbing situation: If we have a pipe which is  uneven or is clogged, water will not flow smoothly through it. Blocked  pipes are literally enough to give people heart attacks: when our  arteries (pipes) are clogged with cholesterol, this impacts blood  pressure (flow) resulting in heart disease.

It is easy to see how these wastes hinder productivity.

TIMWOOD is a standard acronym used to represent wastes relating to unnecessary or avoidable Transportation, Inventory,  Movement, Waiting, Over-processing, Over-production and Defects.

The  classic image of the dysfunctional factory comes to mind: piles of  inventory, teams waiting idly to receive input from other teams, a huge  scrap heap, poor quality outputs, and so on. Waste can also exist in  service environments. The symptoms remain the same, only now instead of a  product (like, a wheel assembly) it is a service (such as invoice  processing) where waste accumulates. Reducing waste is at the heart of  LEAN. Reducing waste helps to improve flow.


Another concept central to LEAN is that of pull.

‘Pull’  is a supply chain management technique. The principle is to take action  when the receiving customer (or process) signals a demand or orders it. By re-stocking only when we actually need to, we minimize overproduction and over-ordering.

Taps  are about pull, too. When we turn on a tap, we get water. We get it on  command, and at a rate that we can control by adjusting the tap. This is  pull at its purest — literally.

Nowadays,  we have sensor-activated taps which take waste-reducing to a new level.  They are activated by sensors, and only dispense a certain amount of  water. That means less water wastage and it also removes the unnecessary  task of turning the tap on and off.

Conceptually  speaking, sensor-based systems usually operate on a pull basis. Take  traffic-lights. Contrast the types that phase at regular intervals,  regardless of traffic build-up, with ones that dynamically adjust their  phasing based on traffic-detectors,  A traffic-light that can detect that the road is empty and reduce the  red-light time accordingly is more efficient for everyone.

The more flexibility there is to cope with demand, the smoother the overall flow. Once again, we come back to the concept of flow.

Why is flow so important? Flow is an integral contributor to the ultimate goal of LEAN — to deliver value to the customer.

The story of LEAN reaches its climax, when we talk about value.


What  is value? Value is what the customer is willing to pay for. It is the  utility a product or service provides. Value is where all the concepts  of LEAN come together.

When  we open the tap and it dispenses hot water immediately, safely, and to  the quantity we specify, we receive the item of value (hot water in this  case). If the flow is not smooth or fast, then optimum value is not  being delivered.

Value is specified by the customer. The series of activities that help create a product or service that a customer has value for, is called a Value Chain.

If  we work our way back from the dispensing of ‘value’ (hot water), we see  a tap, sitting in front of a system of pipes and thermostats that trace  back to a water supply source, and, ultimately, a water body. Factor in  the various suppliers, manufacturers, inter-operable parts, quality  standards etc. and we start to truly envisage what a massively  coordinated effort it is to provide a hot water system — something we  take as basic everyday essential.

LEAN  requires holistic thinking: we need to know the full picture. When we  know the full picture, we can track root causes better, understand value  better, diagnose better and therefore design better.

When we turn on the tap, we’re basically making use of a value chain that dispenses hot water (value) to  us upon demand. If the hot water is dispensed smoothly and swiftly, it  means the flow across the process is efficient and effective. If not,  then we have to ask questions. We use LEAN tools to help us investigate  and improve.

LEAN  is a powerful tool-set which has resulted in tangible and significant  process improvements across manufacturing and service industries. To  appreciate the real value of LEAN, we must see beyond its immediate  appeal as a tool-set.


LEAN thinking is a mindset that centres on continually striving towards perfection.  Process improvement is not a one-off effort. There always remains room  for further improvement. Moreover, waste, variation and overburden  eventually creep back into any process. By continuously removing these causes of poor quality, the LEAN mindset strives, endlessly, to create the perfect process. So that the best possible product or service can be delivered to the customer.

When the concepts of LEAN are interwoven into this discipline of continuous improvement, its true power starts to be unleashed.

LEAN  is about elegance. It is about creating a system (value chain) that can  provide an elegant solution (value) to the end customer, while  expending optimal effort (flow).

For designers, elegance = empathy.
For engineers, elegance = efficiency.
We need both.
John Maeda (Designer, Technologist)

The  hot water tap is the ideal contraption. It has a universally understood  interface — on/off — with progressive stages in between. It is an  elegant solution for dispensing water in controlled quantities, on  demand, and to a required temperature. When we view it as a system, it  is inter-operable and largely standardized in terms of concepts,  vocabulary and materials.

The  next time you brew your tea bag in 250 ml of “freshly boiled water”,  take a few minutes to marvel at the process. Water, originating in a  water body somewhere unknown, is coming to a tap near you. Boiling hot,  within seconds of pressing a button, and at a uniform flow.

Just like making the perfect cuppa, LEAN is also about inching towards perfection.

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