NIST: The Metric Cheese Shop

By The Metric Maven

Extra Bulldog Edition

On Sunday, February 7, 1904, a fire began in Baltimore. It would take 1,231 firefighters to bring the fire under control and when it was over 1,500 buildings would be destroyed. One reason the fire burned unchecked for so long was the absence of national standards for fire-fighting equipment. Fire engines from Philadelphia, Washington D.C., Atlantic City, New York City and other metropolitan areas arrived on the scene. Unfortunately, many fire departments were unable to help as their hose couplings would not fit Baltimore’s fire hydrants. Those fire-fighters could only watch as the fire engulfed more and more of the city. It has been claimed that over 600 different sizes and variations of fire hose couplings existed at the time. This was similar to what French Engineer Charles Renard encountered with balloon cables, which caused him to develop preferred numbers.

The National Bureau of Standards was founded in 1901. Two metrication advocates championed its creation, James H. Southard, and John Shafroth. The Great Baltimore Fire directly demonstrated the need for mandatory standardization of fire-fighting equipment. Furthermore, no standards for building construction (building codes) existed, which allowed the fire to rapidly spread.

One would think that with the lessons of the Baltimore fire, and the establishment of a government agency for standards, that soon fire departments across the country would be induced to adopt national standards for fire-fighting equipment.  On March 22, 1975 a fire started at Unit one of the Browns Ferry Nuclear Reactor.  Plant employees attempted to extinguish the fire despite the fact that professional firemen from Athens, Alabama were on the scene. They mistakenly believed there was a problem with a nozzle at the end of a fire hose. This in turn caused the employees at the plant to request a replacement nozzle from the Athens fire department. The threads on the the fire department’s nozzle were not compatible with those of the fire fighting equipment purchased by Browns Ferry.  Because of this, the nozzle would not stay on the end of the hose.

Well, certainly by now, well over a century after the founding of NIST, we would have national standards for fire couplings and this would not be a problem right?  According to Wikipedia:

A national standard for fire hydrant and hose connections was adopted by the National Fire Protection Association. However, inertia remained, and conversion was slow; it still remains incomplete. One hundred years after the Baltimore Fire, only 18 of the 48 most populous American cities were reported to have installed national standard fire hydrants.[18] Hose incompatibility contributed to the Oakland Firestorm of 1991: although the standard hose coupling has a diameter of 2.5 inches (64 mm), Oakland‘s hydrants had 3-inch (76 mm) couplings.[19]

The idea of standardization strangely seems to be at the bottom of the priority list of many engineers. Those who have seen the movie Apollo 13 were reminded that the the carbon dioxide scrubbers for the Command Module and the LEM were not compatible. Fortunately, they were able to engineer their way to compatibility with a duct-tape solution. One should not rely on good fortune instead of planning and standardization, but in the US hoping for good fortune appears to be the standard back-up plan.

The lack of standardization in the US can and has cost lives. The acronym NIST stands for The National Institute of Standards and Technology. A year ago on May 24th 2013 (2013-05-24), on the Friday before Memorial Day weekend, a time when bureaucrats know that news media is generally not paying attention, the Director of NIST, Patrick D. Gallagher, penned a response to a citizens petition requesting that the metric system be adopted as the sole measurement system in the US. His response can be succinctly stated as he supports a “do your own thing” approach to standardization. Standardization is just too confining of a concept for a standards institute to embrace apparently. The title of his response, in case readers have forgotten, is Supporting American Choices on Measurement.  It is well known to metric advocates that 95% of the world’s population uses the metric system. It would appear from just a cursory inspection of this  fact, that one could, with reasonable certainty, state that the metric system is probably the most successful standard in the history of humanity.  The director of the US government body which is tasked with standards, cannot even agree with a petition that the metric system should be the standard of the US?

When one is confronted with Dr. Gallagher’s assertion that the best standard is a lack of standards, and  I remind you he is the director of the standards body of the US, one’s mind can only interpret the strange dark and contradictory humor of this apparently willful cognitive dissonance in but one way—–by resorting to a Monty Python Metaphor. One of the most famous of the Python’s sketches is The Cheese Shop. A patron walks into a cheese shop and requests some cheese. He requests all different manner of cheeses one by one, red Leicester? Tilsit? Caerphilly? Bel Paese? Red Windsor? Stilton? Ementhal? Gruyere? Norweigan Jarlsburg?….. These requests continue ad nausium until finally:

Mousebender Well let’s keep it simple, how about Cheddar?
Wensleydale Well, I’m afraid we don’t get much call for it around these parts.
Mousebender No call for it? It’s the single most popular cheese in the world!
Wensleydale Not round these parts, sir.

The exchange continues as the patron continues to request cheese after cheese until finally he states:

Mousebender It’s not much of a cheese shop really, is it?
Wensleydale Finest in the district, sir.
Mousebender And what leads you to that conclusion?
Wensleydale Well, it’s so clean.
Mousebender Well, it’s certainly uncontaminated by cheese.

I could see a similar exchange with the Director of NIST acting as a standards proprietor where one could request mandatory metric industry standards for fire hose couplers, foot measurement, wire sizes, drill bit sizes, sheet metal thicknesses, medical weights and heights of humans, over the counter medical dosages and on and on. Each time the Director would parrot back “no.”  And when one states “it’s not much of a Standards Institute is it?” this phrase might be met with “finest in the US sir.” Indeed, NIST appears to be quite clean, and uncontaminated with metric standards for the US. As in the sketch, the most popular world measurement standard, which is metric (aka Cheddar) is to be found nowhere as a standard in the standards shop.

It is hard to take NIST’s assertion that it is a standards institute seriously when it promotes the notion that a lack of standards is of exceeding utility to the US, and serves as an illustration of  what makes our nation great. NIST is a Metric Cheese Shop, with no Cheddar, and it is completely uncontaminated by cheese as far as I can tell. It is sad that a scientific standards organization has been turned into a worldwide metric joke. At least the Python players had much better writing, and were actually funny while making important points. Patrick D. Gallagher’s response last year was so feckless, it was almost a killer joke to metric advocates. Now stop me if you’ve heard the one about the 600 choices of hose couplings available to the Baltimore fire department.


In 2012, I wrote an essay entitled Feral Units Endanger Our Health. In it I detailed the well known problem of the confusion between teaspoons and tablespoons. I pointed out that confusion between the two units can lead to a 3:1 or 1:3 dosage mistake. I then cited a column from JAMA, The Journal of The American Medical Association, dated September 20, 1902 (page 712), which is reproduced here in the upper left. The 1902 JAMA column advocates for mandatory implementation of the metric system through the Shafroth Bill. It was brought to my attention (thanks Dr. Sunshine) that just two days ago (2014-05-21) JAMA published a column which yet again addresses the same issue over 111 years later. The new column is entitled Group Urges Going Metric to Head off Dosing Mistakes and is authored by Bridget M. Kuehn (pp. E1-E2). The article opens with modern day examples of the problem:

The article goes on to state that “about 3000 to 4000 children are treated in emergency departments each year as a result of medication errors by a caregiver. Poison control centers in the United States also field approximately 10 000 calls each year about dosing confusion,..”

It has been said that a working definition of insanity is to do the same thing over and over and expecting a different outcome. This apocryphal quotation danced in my mind as I read “The CDC worked with the US Food and Drug Administration and the Consumer Healthcare Products Association to develop voluntary guidelines that were published published in 2011.”  Our current answer to all measurement problems in the US is to adopt voluntary guidelines.

The suggestions are all mostly reasonable, such as including a dosage device with medication which does not use “unusual units” (I guess they mean metric?), adding zeros before decimal points (they could also adopt the whole number rule), and “dosing devices that are not substantially larger than the largest recommended dose of the medication.” Further it is stated:

The CDC recommends using only milliliters as a measure for liquid medications to avoid confusion between teaspoons and milliliters and avoiding relatively unfamiliar measures such as drams (a holdover from apothecaries). The CDC wants the dosing device with the appropriate unit of measurement included with the medication to avoid caregivers using a kitchen spoon or other implement that uses a different unit of measurement. Further, the enclosed device should only have the recommended doses labeled on it to make it even easier and safer to use.

 The ISMP (Institute for Save Medication Practices) goes further than the CDC recommendations and argues for expressing a patient’s weight only in kilograms. The “ISMP, explained that because there are 2.2 kg per pound [sic], switching back and forth can lead to 2-fold errors in dosing of medications by weight.”  Once again, in an echo of the 1902 JAMA column they point out that over the counter medications need to conform to these voluntary recommendations. The article also argues against the use of dual-scale dosage devices.

The article goes on:

Stephen C. Mullenix, RPh, senior vice president of public policy and industry relations at NCPDP, said the white paper is “a call to action” for pharmacists to make sure dosing is correct. They can verify with the prescribing physician to ensure they understand the dosing for a particular drug.

I’m sure the authors of the 1902 JAMA column also saw their words as a “call to action.” The big difference between then and now is the Meyer Brothers backed John Shafroth’s bill for mandatory metrication.

The article ends with the problems encountered when using electronic prescriptions. The example cited is of a doctor prescribing in milliliters and when it arrives electronically, the pharmacies software has a default setting to teaspoons. The article ends with a familiar modern refrain:

Converting all dosing and patient weights to metric is going to take time, Cohen acknowledged. But already he noted that soda cans and many other types of packaging already use metric units and that people will learn the conversions over time. “This isn’t something that is going to happen overnight,” he said.

The lack of mandatory metrication in this country is making people sick, costing our economy financially, and showing us for what we are, a nation that is willing to sacrifice people on an altar of ideology rather than acknowledge and engage with reality. Given our history, I suspect that in another 100 years we may still be waiting patiently for these voluntary recommendations to adhere.

Meyer Druggist April 1922

Metric Tiger Paws

By The Metric Maven

Bulldog Edition

I recently took my car in for an oil change, and to have the dealer look it over and verify it as roadworthy for a trip back to the midwest. Above the desk of the person helping me was a flat panel monitor which was explaining “The Penny Test” for tires. Public service commercials years ago showed that if you put a penny into a tire tread with the top of Abraham Lincoln’s head in the tread, and the top of his head was not covered, the tires were worn and needed replacing. This video showed different lines along the coin, gave a value in terms of 1/32 of an inch and had red, yellow and green backgrounds for each value. I shook my head and thought: “Wow, that’s crazy, who knows how much 3/32ths of an inch is or how it compares to 7/32nds? Millimeters would actually mean something.”

I sat and waited for them to finish. A pleasant woman came with the inspection results. She showed me that my brakes were mostly ok, but close to needing to be changed on the front as there was only 3 mm left. On the back it was about 4 mm and could also wait. Ah, millimeters, no 32nds of an inch. But there was also some bad news. I had recently purchased new tires, and one of them had a screw puncturing the top, and a nail in the sidewall. The tire could not be fixed because of this. It was slowly leaking. It was down to about 20 PSI (138 Kilopascals) the normal value is about 32 PSI (221 Kilopascals).

I immediately drove my car to the local tire shop where I had purchased the tires. To my amazement, the tire was in warranty. The bad news?—the tire had been discontinued. This was the third time Michelin had discontinued the recommended tire. As I needed to go on a trip, I put a very similar tire on. The person helping me indicated that a new tire had been designed to replace the old version, but it was not of a compatible size. The next time I was in and needed all new tires, he suggested I purchase the new tire model. I asked what the difference was. I was told one important change was that it is 10 millimeters narrower than the other design. My mind screeched to a halt.

“Ten millimeters?—are tires all metric?”

“Well, mostly, most all of them are now.”

I asked the technician what he meant. He then escorted me over to a nearby wheel rim to explain. He pointed out that a 14 inch rim is measured from the diameter of the bead (the seal) and the width of the rim is also in inches. The bolt pattern is in metric, and the standoff of the mounting plate for the rim is in millimeters, in this case it was 41 mm. I asked if the bolts were all metric.

“Well, mostly, they are M12 x 0.5 but on older types of wheels like those still used on campers and trailers they are often 9/16″ and the wheels are all in standard.”

AHHHHHH!….there it was…that word standard again, for barleycorn inches. I told him “well, it’s standard for 5% of the worlds population.”

He smiled and said “only we could make it this complicated.”

How could I argue with that? The technician then explained that for common passenger tires one can read the set of numbers found on its side and determine important properties of the tire.

The designation I saw on a tire in the show room  was 215/55 R16 97H.  The 215 means the width of the tire is 215 millimeters. The number after the slash is the aspect ratio which
is 55. So the height of the sidewall is 0.55 X 215 mm or 118.25 mm. So far so good. The R means radial tire and the 16 means sixteen inches. So the tire designation is not all metric, but is a pigfish combination. Oh…the pain. Clearly with all the new cars, and new tires that have been designed over the years, the radius could have been changed to 400 mm with little problem. What I saw was that all the sales literature is in inches for the rims and tires. One would never see a millimeter where showroom information met the American consumer.

The number 97 is the load index of the tire, which in the typical indirect designation of which Americans make a fetish (like gauge numbers), it does not correspond directly to any known units. A load index table tells you that 92 actually means 1389 pounds. This sort of irrational designation is what makes America great! My mind kept nagging me with hope that perhaps the radius designation in inches is actually a metric value that was converted back to inches and rounded. I consulted Wikipedia about tire code, and unfortunately this appears not to be the case:

  • 2 digit number: Diameter in inches of the wheel that the tires are designed to fit. There is the rare exception metric diameter tires, such as the use of the 390 size, which in this case would indicate a wheel of 390 mm in diameter. Few tires are made to this size presently.[6]


With little else to do while waiting for the tire to be mounted, I asked about the “penny test” and the 32nds of an inch. I was told the “penny test” was mostly out of favor these days. I asked what the values were for red, yellow and green for tire tread in 32nds of an inch. There seemed to be some uncertainty. Finally one of the attendants tossed a gauge in front of me and said “here, you can keep this, it will tell you.”  Indeed it does. It is a six sided plastic polygon cylinder which has a scale in 32nds on it. Here is what it states:

0-3 32nds is Red
3-6 32nds is Yellow
6-32 32nds is Green

It was clear to me they used the gauge constantly, but the numbers on it remained foreign. This is probably because 1/32″ is not exactly a common unit and they just look at the color on the gauge. This caused me to look back at the print out I was given by my car dealer for the brakes as it had the same colors. When I looked, I was surprised. Here is the top line:

I had completely missed the tire tread data of 7/32nds for my tire tread. There it is, side by side, fractions of inches and millimeters. There is not even a designation for inches, it just has fractions! It also appears to disagree with the gauge I was given at the tire store–by 1/32 of an inch.

Let’s see how millimeters might work. For the tire shop:

0 to 2.5 mm is Red
2.5 mm to 5 mm is Yellow
5 mm to 25 mm is Green

For my car dealer:

0 to 3.0 mm is Red
3.0 mm to 5 mm is Yellow
5 mm to 25 mm is Green

Either set of values seems simple, provides dimensional meaning, and is easy to remember when compared with fractions of an inch. So, does having tread thickness in thirty-seconds of an inch make the tread thickness more understandable because it’s in “standard” units? I don’t see how having two sets of units, where one uses fractions and the others decimals makes any sense. Perhaps that’s why we in the US do this, to obscure any rational understanding.

Cars may be over 99% metric, but until the US switches and industry is compelled to exclusively use the metric system for commerce, there will never be 100% anything in the US, other than confusion.