5S is one of the key practices of the Toyota Production System. The 5 S’s derive from five Japanese words which when romanized, begin with the letter ‘S’: Seiri, Seiton, Seiso, Seiketsu, and Shitsuke. The Japanese word Seiso translates to cleanliness. There is no doubt that cleanliness of a workspace can contribute to efficiency, safety and a positive work environment, but substituting "shine" for Seiso because it is an English word which begins with the letter 'S', risks a literal interpretation which results in none of those outcomes.
This article comes from my Navy experience and in particular, the use of Epoxy-Polyamide paint in enclosed environments. It points out the risk of focusing on looks over function.
A Submarine Story
Generally speaking, the operational range of a nuclear powered submarine is limited by food, not air or water. There is no way to replenish the food consumed while under way, but the ship can make plenty of water, and air is recycled, run through precipitators to remove particulates, and charcoal filters to remove organic compounds, most notably those which involve odor. CO2 is removed through scrubbers, and O2 is produced through electrolysis. Because submarines are closed atmosphere systems, atmospheric contaminates are a big thing. Aerosol cans for things like deodorant and canned shaving cream are not allowed. Other materials which are atmospheric contaminates, but which were occasionally necessary, things like rubbing alcohol and paint were tightly controlled substances. Paint was a problem because it cures and off-gasses for sometimes several days after it dries to the touch. As a result, all painting was supposed to be completed at least three days before getting under way.
Or at least that was the idea.
The Shine Factor
Most anyone who has ever been in the US Navy will be able to tell you about the importance of shine. Looking sharp, squared away and ship shape were imperatives. Had to impress the higher ups. I had one commanding officer who insisted we tear up the standard navy issue blue linoleum in the engine room and replace it with white tile. Picture this now, white tile next to large turbines whose journal bearings were being lubricated by copious amounts of oil. At the end of every shift, the bearing ends of most equipment had a light dusting of oil that had been atomized and then deposited on the equipment, floors, walls, my eye glasses. This would get wiped up every shift, but after about two weeks, that shinny white tile the captain was so enamored with, was turning yellow. While keeping white tile next to steam turbines white was an annoyance that produced no value, (shinny white tile didn’t cause damage), the use of epoxy-polyamide paint to keep the bilges looking shinny and new however, became a serious operational issue.
Motor Generators
The majority of equipment on a submarine runs on the same alternating current (AC) that runs your homes and businesses. They even have electrical outlets, just like your house, so you can run that electric shaver you needed to use since you can’t use your can of shaving cream. This power was supplied from shore or, when underway from the turbine generators or backup diesel generator.
But submarines also have batteries, very large batteries. These batteries provide power for critical systems in the event of a loss of primary power sources, for example a safety shutdown of the reactor plant. The submarine runs on alternating current, the battery is a direct current (DC) device, so you need something to convert between AC and DC forms of electrical energy. That device is known as a motor-generator, essentially two electric motors coupled together. On one end, there is an AC motor, and on the other end, a DC motor.
These devices were pretty big (about 300 horsepower on each end), and pretty important. Without them, if you loose AC power, you loose all those important things like lighting (submarines don’t have windows), and hydraulics (which operate control surfaces, which keep you from sinking).
Bilges
These motor-generators sit in a machinery space in the lower level of the submarine. The bottom portion of the hull in these spaces, like most boats, are what are known as the bilge. Bilges it turns out, are convenient places to collect water. Pumps are designed to leak a small portion of water to lubricate the pump shafts, steam moisture traps drain to the bilge, sea water vents drain to the bilge. Some of the equipment would leak small amounts of oil, and that would collect in the bilge as well. Every shift or two you’d pump this to an oil separating tank and then the water would eventually be pumped overboard.
None of this was a problem, except that sea water is corrosive, and over time with oxidation and hull flexing, the paint would crack and chip, the bilges would look rather unappetizing. Remember though, this is the Navy. Shine is in, bilge scum is out. So during our regular maintenance while tied up to a tender, we’d be down there chipping out old paint and applying shiny new paint the bilges. We used the best paint then available in MIL-Spec formula, epoxy-polyamide paint.
Fortunately, epoxy-polyamide paint hardens fairly quickly, forming a nice, hard shinny finish in just a few hours. The smell dissipates within two days, and life is good. Well, not quite as good as it may sound. Epoxy cures as a result of heat generated through the chemical curing process. To insure this actually works, the paint surface was supposed to above 60 degrees Fahrenheit. We were refitting in Holy Loch Scotland, where the water temperature, and thus the hull temperature, was a balmy 34 degrees Fahrenheit. The result was an incomplete cure. Even at the recommended cure temperature, the cure process off-gassed small amounts of ammonia. Not enough to be an environmental hazard to people, but the motor generators were something all together different.
She was amazingly pragmatic about this since I could usually get things back together and working.Commutators and Copper Oxide
Remember those big 300 horsepower DC motors I mentioned above that were part of the motor-generators. Well, like most DC motors, they have these things called commutators. Commutators are how you get electrical current from the stationary motor frame to the rotating shaft (the rotor) of the motor. The rotating commutators is made out of copper, and electrical current is passed to the commutator through a set of carbon brushes which ride on the copper. Well, actually, the carbon brushes ride on a very thin layer of copper oxide that forms on the commutator. Copper oxide is what keeps the Statue of Liberty in New York harbor from falling apart. Some forms of copper oxide have very important characteristics that are good for commutators. First, they are very hard, protecting the copper from wear. Second, it polishes up really smooth, meaning there is very low friction for the carbon brushes, which means they don't wear out very fast.
OK, so here’s what we have so far. Big DC motors, with big copper commutators with black copper oxide layer which protects the copper and brushes. And these are now in an enclosed space with incompletely cured epoxy-polyamide paint which is off-gassing low levels of ammonia gas. Oh, and ammonia gas, it really likes to attack copper oxide.
The result of ammonia gas attacking copper oxide is that the copper oxide gets soft, and is worn off by the carbon brushes. After making the bilges nice and shinny, we started noticing that the commutators on the motor generators, which should have a copper-black appearance, were really shinny bright copper. Of course, that bright shinny copper had much higher friction than the copper oxide, so it wore down the carbon brushes. When carbon brushes get worn down, that carbon goes into the windings of the motor, and eventually causes electrical shorts in the generator windings.
Before we tried to make the bilges all shiny new, we were doing bi-monthly maintenance on the motor-generators, well, every two months. Monthly maintenance consisted of shutting the machine down, blowing out any carbon that had collected in the windings, and if necessary, which it generally wasn’t, replacing the carbon brushes. After we made shiny bilges, we were doing monthly maintenance every three days, and it still wasn’t enough. In seven patrols I was involved in two motor-generator replacements, which since it entailed cutting through three inch thick, pressure rated, water tight bulkheads, were nontrivial activities.
The Point
The point of all of this is that it was not a big issue to maintain sufficient cleanliness to ensure a safe, productive workspace without negatively effecting any of the equipment. Yeah, the bilge was looking a bit rusty, but HY80 steal is pretty corrosion resistant, and with 3.5 inches of it between us and the water outside, not a safety concern. But it didn’t shine. And to make it shine cost the Navy enormous amounts of money, lost operational time for maintenance and down-time, costly parts and maintenance, and a severe compromise of reliability.
The Moral of the Story
5S is a set of principles, not practices. An appropriate translation of Seiso is cleanliness, with an intention of providing a safe, reliable, efficient and enjoyable work environment. It should not be an excuse for an ego trip. Keep your eye on the goal. Yes, we wanted to keep oil cleaned up so no one slips and falls. Yes, we want to vacuum those fallen screws off the assembly line so they don’t jam the conveyor system. Yes, we want to sweep and dust so the space is a pleasant one to spend time in. But when implementing 5S, don’t use the shine term. It doesn’t typically provide customer appreciated value.