Slip Meters: How Much Do You Need?

For an experienced person, a slip meter is an important tool. If you don't know exactly how you will use the device in a day-to-day program, don't buy it.

• By Barrett Miller
• Mar 01, 2003

SEX sells products, but when it comes to moving merchandise, nothing beats fear.

It's a painful reality of modern marketing: If you can create an atmosphere of fear, the product that takes away the immediate anxiety sells. This principle applies to everything from underarm deodorant to floor care products.

I can think of no better example than a port authority that purchased a $3,000 slip meter for $6,000 and then found it was anything but what they needed. The device was not that complicated, but it was fragile and no two employees got the same results. In an effort to chase decimal points, they neglected more important things.

The expensive manufacturer was in the business of selling machines and knew little about floor care. It was time to change directions, but how? Having been in various lawsuits, the authority feared another and being held to unrealistic demands based on a better machine. Is this thing approved? Does OSHA require brand X or Y? Then it became clear, it was not ASTM that demonstrated their standard of care, but the systematic, professional care they provided to their public facility.

I never saw anyone slip over a decimal point, but I have seen some fall over almost everything else. Most people say "he slipped," when they mean "he fell." This leads to armies of expert witnesses marching into the field with $10,000 slipmeters looking for a decimal point upon which to base a lawsuit. Your purchase of a $10,000 slip meter won't change that. Court testimony is often no more that a ritualistic dance of forensics. Measurements are sometimes useful, sometimes just a matter of smoke and mirrors.

In most cases, the expert witness would simply find or imagine some characteristic of your method that makes his gadget more official, or more legal, or more accurate. In any case, he will have created a question of fact for a jury to decide--which is why he was hired in the first place.

First, Hire Good Employees
In college, I worked for the head custodian at the National Center for Atmospheric Research.

He was smart and highly paid, making as much as most of the Ph.D. chemists. Gene knew his floors and knew his products. He knew how products should be used and what they looked like when they failed. He knew that in most cases where people fall on slippery floors, they fall on contaminants. He used a slip meter to verify that batches of new products met expectations and to determine when quantities of floor products had failed. He knew contaminants are hard to measure and the numbers are largely meaningless, even in civil litigation. He knew what we all know: Water, oil, and banana peels can be dangerous.

The trick is to isolate the contaminants and remove them, not to measure them. Your most important asset is your employee, not your slip meter. If you hire good people and keep them happy, you will be OK.

Rules of Thumb for Buying Slip Meters
Slip meters are sold as go/no go devices, which is unfortunate. Given the complexity of the subject, it is wrong to expect a red light/green light answer from a slip meter. A slip meter can be important. Any device that measures friction simply creates a contrast between two variables. The answer often lies in the isolation of these variables.

At best, a slip meter is an aid to the person asking questions. It can be an invaluable aid to intuition, but a device can never answer the most important question: Why? The answer to "why" is found in a knowledge of materials and the application of Boolean logic.

Neither OSHA nor any other regulatory body requires the purchase of a single brand of expensive machine, or for that matter, any machine at all. If you choose to purchase a slip meter, or tribometer, you might follow this rule of thumb. If you purchase a $5,000 tribometer, make sure you hire a $50,000-per-year employee to handle it. In most cases, you are better off with a modestly priced slip meter that you can learn while you use. In the final analysis, it is not the fiddle, but the fiddler.

Slips and Falls in Retail
There are recognized duties in the retail trade relating to floors.

First, if there is a banana peel on the floor, pick it up. Learn to recognize contaminants in the workplace and prevent them from creating an accident. Use floor finishes that are compatible and that are manufactured to acceptable industry standards. Hire, train, and keep people who are conscientious and care about their work. Train and supervise them as though they are valued members of your industry. They will respond in kind.

My first professional investigation involved a pregnant woman who fell on spilled soap in a grocery aisle. No slip meter would have stopped this accident. In almost every case, it is better to behave up to the quality of what you already know rather than make a purchase of any kind. If you listen to your inner voice, you'll be OK. You know, for example, that wet, icy, salt-covered areas can be dangerous. Respond to the problem; don't measure it and wait for a committee meeting. Rarely are contaminants invisible.

If you can see a dangerous condition, fixing it is obvious. On those rare situations where the contaminant is a failed product and is not visible, routine testing of floor conditions with an inexpensive slip meter is useful. It is useful primarily as an aid to intuition and plays only a small part in a systematic program.

Conclusion
There may be a slip machine guru somewhere who can train you in floor care, but I doubt it. In most cases, a $500 machine is as good as a $17,000 machine in the hands of an experienced person. For an experienced person, a slip meter is an important diagnostic tool. However, if you don't know exactly how you will use the device in a day-to-day program, don't buy it.

Product distributors are still your best source of information if you use them critically.

Learn all of the characteristics of the products you use, not just the coefficient of friction.

If you have a crisis, ASTM will not be there defending its decimal points.

Floor problems are not dependent on figures in the third decimal point.

In cases where statistical measurement is important, you will find you are dealing with gross numbers.

The device manufacturer will not be in your plant defending your actions if things go wrong. So do your best, and take it easy.

This article originally appeared in the March 2003 issue of Occupational Health & Safety.