Ever heard of muda, mura and muri? You have now. These three terms may seem completely unfamiliar, but – in the way that the English language often does – within a few years they might become part of normal speech.
The words are Japanese and originated in the Toyota Production System. Some years ago two senior managers, Taiichi Ohno and Shigeo Shingo, were examining the waste in their factory. They gave it the umbrella term of "muda" meaning activity that is wasteful and doesn’t add value. They went on to define seven different types of "muda", the two most common being "mura", meaning "unnevenness" and "muri" meaning "overburdening".
What application does this have to sustainability? A lot: in a recent BRE paper the terms were expanded upon: "muri" (overburdening) happens "when processes and operators do not have sufficient time to carry out their work which affects the whole process flow." Meanwhile, "mura" (unevenness) "occurs when products are batched together and pushed through a production plant."
These terms are central to the science of "lean manufacturing" and, though they were developed in the context of a busy car plant, they apply increasingly to the housing and construction sectors where, of course, waste should be minimised, if not eliminated.