In recent years, some companies and consultants have come up with their own versions of the 5S model by adding an additional S to make it 6S. Most commonly, the 6th S stood for Safety. Their aim is to place special emphasis on Safety. I have even come across one company that adopted 7S. Besides Safety, the additional S came from a Japanese word beginning with S. I am sorry I cannot recall the Japanese word, but I think the meaning had to do with work morale. I personally think it is not a good idea to add anymore S’s to the original 5S model.
1. The 5S Model is already a fairly well-known and universally accepted management concept. The term and its meaning too have become quite standardized. Hence, to come up with something like 6S will only serve to confuse the public.
2. Often the 6th S, such as Safety, does not fit logically into the 5S meaning. Each S in the 5S model denotes a set of actions or approach. Hence Seiri is Clearing; to sort and discard unnecessary items, Seiton is Organizing; to arrange necessary items systematically and so on. The result of these actions is better safety, less waste etc which further leads to lower cost and higher profitability. Safety being a noun simply does not fit into the set; unless these organizations are prepared to re-define the each of the 5 Ss in terms of nouns such as clutter, orderliness, cleanliness etc.
3. In the case of Safety, it is superfluous because it is already addressed the other 5S steps; especially Seiton, and specifically Visual Control (see example below). Safety is the result of 5S not an additional ingredient in the 5S dish. In Chinese we say don’t draw a snake and add legs to it – 画蛇添足。
Instead of trying to modify the conventional 5S model, I think companies should focus their energies on implementing the 5S more effectively. Sometimes companies having practiced the 5S for a couple of years become complacent and think that they ‘have arrived’ and try to expand the 5S movement by adopting 6S. The workers will surely be able to see that they have added nothing new. Worse still, they will conclude as I do, that the managers do not really understand what is 5S in the first place.