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 (see the broken window theory). 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. A good example of taking “shine” too literally comes from my Navy experience and in particular, the use of Epoxy-Polyamide paint.

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 sub 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 were 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 glasses etc. 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 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 couldn’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.

You might already see the problem here: 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.

A motor generator is essentially two electric motors coupled together. On one end, there is an AC motor, and on the other end, a DC motor. Actually, the way these things work is that either side (AC or DC) can be either a motor or a generator. The function depends on the voltage at each end.

Normally, with the turbine generator creating power, the AC end would be running as a motor and the DC end as a generator to charge the batteries. In a loss of power, a shutdown of a turbine generator for example, the voltage drop on the AC end would cause, almost instantly, a change in power flow, the DC side would become the motor, the AC side the generator.

These devices were pretty big (about 300 horsepower), 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, is what is 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. When you returned from see, the oil separating tank would be pumped to a recycling facility. None of this was a problem.

Well, none of it was a problem, except that sea water would carry plankton which would turn into bilge slime, and the oil would leave a film, and over time with oxidation and hull flexing, the paint would crack and chip. After a time, 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.

I won’t say this is the worst job I ever had in the Navy, but this stuff is not to be toyed with. The fumes will get you high. One of my shipmates suffered abnormal cardiac rhythms (quite unusual for someone in his early 20’s) after too much unprotected breathing of these fumes. Handling this stuff safely meant we typically painted, hanging upside down, in respirators. It was one of the many aspects of the Navy I have never missed.

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.

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. Copper oxide also has some very important characteristics that are good for commutators. First, it is very hard. It protects the copper from wear. Second, it polished 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 monthly maintenance on the motor-generators, well, monthly. Monthly maintenance consisted of shutting the machine down, blowing out any carbon that had collected in the windings, and 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 a water tight bulkhead, 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.