## Using a Pipe Diameter Tape Measure Is a No-Brainer

If you have a pipeline and need to find the OD (outside diameter) it makes sense to use a pipe diameter tape measure. Even a chimp could be trained to use one. (I think). All you do is

1. Wrap the tape around the pipe.
2. Read the marking where the zero mark touches the tape.
3. Even though the tape is wrapped around the circumference, it is marked by a factor of pi, so it gives you the diameter.
4. You’re done.

Now it’s time to enjoy the rest of the day in the shade.

## How to Solve Problems with a Pipe Diameter Tape Measure

A tape measure can solve basically one problem….How long is the item? But a pipe diameter tape measure can solve a short list of problems for you.

• What is the outside diameter (OD) of that pipeline, without having to cut into it. You don’t even have to divide by pi.
• What is the diameter of a tree trunk.
• What is the accurate diameter of a tire.
• What is the diameter of a beach ball, when fully inflated.

Even if the pipe is distorted, and the cross sectional diameter would be different in different directions, you can do it. The pipe diameter tape measure can tell you what the diameter would be, if it weren’t distorted. That’s because the measurement is based on the circumference. The tape automatically divides by pi (3.14159) for you.

## The Pipe Diameter Tape Measure Takes on a New Function During the COVID-19 Situation

The pipe diameter tape measure is normally used by pipeline workers and inspectors. They wrap it around the circumference of the pipe, and read the

diameter size on the tape. Now this useful tape can take on a new use during the COVID-19 lockdown.

For those of you who are forced to stay at home every day, you may have discovered the comforting appeal of the refrigerator. It’s always there with food for when you are hungry. It’s even there when you are not hungry, but just need some comfort. If you have a bathroom scale, you may have noticed that the spring might be getting weaker this month. Or, could it be that you are actually putting on weight?

A Lufkin pipe diameter tape measure can be a fun way to try to prove that your bathroom scale might be broken. Wrap it around your waist or your arm, and see for sure if you are getting too chummy with the Frigidaire.

LOL

## 5 Myths About The Pipe Diameter Tape Measure

The history of the pipe diameter tape measure is probably darker than its future. Once these 5 myths are explained, this little tape measure will experience much success.

1. Nobody needs a pipe diameter tape measure (OD tape).
2. It is too hard to use. Only an expert can use it.
3. It is probably too expensive.
4. A regular tape measure can do the same job.
5. My customers don’t want one with my company logo on it.

1. The “outside diameter tape” is used by plumbers, pipeline workers, electricians, car and boat repairmen.
2. All you do is wrap it around the pipe, and read off the diameter.
3. It compares to the price of many other pocket tapes.
4. Maybe so, but you would have to correct for the fact that you can’t readily see the zero mark. You would have to use the one inch or two inch mark, and subtract that from the total, then divide by pi. A pipe diameter tape measure has the zero conveniently located away from the end of the tape, to make it easy to line up.

Here is the most popular “pipe tape”:

## A Big Secret About the Diameter Tape Measure

Diameter tape measures are made for wrapping around pipes and poles, to find the diameter. That’s a good enough reason to keep one in your tool box, garage, and vehicle. But there’s one feature that no one talks about, until now….

The other side of the diameter tape measure is a regular tape measure, in inches or centimeters. It measures length, not diameter. So, even though it is a special tape, it is also a handy every day tape, too. Lufkin, and the other manufacturers, thought of everything when they designed these handy pocket tapes. Everyone should have one or two.

## What Will Pipe Diameter Tape Measures look like in 2030?

There are distance measuring apps out there, but measuring the diameter of a pipe presents a unique measuring situation.

• Calibration. There will need to be some way of checking to see if the app is working correctly. You will need to measure a known standard to see if the app is measuring right. If not, there needs to be some way of calibrating or adjusting the reading, to make it accurate. In other words, if you measure a 2 inch pipe, and the app says 2.1 inches, you need a way to adjust the setting to read 2.0 inches. Otherwise, when you measure a 3 inch pipe or any size pipe, the measurement would be off.
• Calibration should be done with different sizes of pipe, to make sure you will get an accurate reading at any of those sizes.
• The curvature of the pipe needs to be considered. You aren’t taking a picture of a 2D object. The pipe is 3D, so your camera may not see the top and bottom of the pipe as being 180 degrees away from each other. If you are too close to the pipe, you wouldn’t see the full 180 degrees. So your measurement would be too small.
• Resolution of measuring. A pipe diameter tape measure normally has a resolution of 100th of an inch diameter. Can a smart phone app be that accurate?
• The nearness of the object. For calibration, we would need some standard distance from the cell phone. Maybe this could be accomplished by using an object like a 12″ ruler, placed between the pipe and the phone. Hopefully, a less mechanical method will pop up.

If you know of an app that can accurately measure pipe diameter, please let me know. If one does not exist, I’m sure it will be invented in the near future.

## Who Makes Diameter Tape Measures?

There are 4 main manufacturers of diameter tape measures.

1. Lufkin® has a world-wide reputation for making high quality tape measures. They used to make them in the USA, but they have shifted the production facilities to Mexico. Some of the tapes are made out of a cast case, which is highly polished and chrome plated, like the w906pd. Others, like the w606pd have a stamped case, which is shiny and chrome plated.  A third type of case is black plastic, like the asw616pd. However, the tape blade inside is the same in all 3 types of cases. It is capable of measuring diameters up to 23 inches.
2. Pi-Cobra is a brand name for diameter tapes made with

#### Pi-Cobra Diameter Tape, Metric

a cast case which is chrome plated. It can hold a longer tape blade, capable of measuring diameters up to 38 inches. The case is very durable. These are manufactured in China.

3. Various other Chinese manufacturers make versatile OD tapes like the 416-04-024-P. The back side of the tape measures diameter up to 24″ in 100ths of an inch or 610 mm. The case is plastic, and has a key ring attached to it.

4. The UT-56675 is made in the USA. It is capable of

measuring pipes up to 45 inches in diameter. This is a belt tape, not a pocket tape. The calibrations are in tenths of an inch diameter.

## The Mystery of Pipe Diameter Tape Measure Codes

Lufkin pipe diameter tape measure products are available with different scales. To find the right tape for your needs, here is how to read the codes that are embedded in the SKU numbers.

• “P” means that it is a “pi” tape, also known as a diameter tape.

Examples are w606p, w906pd, w606pm, asw616pd, w606pd, w906p.

• “D” means that it measures in tenths of an inch. If the “D” were missing, it would measure in 64ths of an inch.

Examples are w906pd, asw616pd, w606pd.

• “M” means that it measures in metric scale.

An example is w606pm.

## 3 Easy Steps to Use a Pipe Diameter Tape Measure

This time, we won’t get into the geometry theory of pi that we had in high school. The magic of a pipe diameter tape measure is its simplicity of use. Here are the 3 steps to find the diameter of a pipeline:

1. Clean the pipe surface. Soil and any other contamination, of course, will make the pipe seem bigger than it really is.
2. Wrap the diameter tape around it, with the diameter scale visible to you.
3. Simply read off the tape. This will be the diameter, even though the tape is wrapped around the circumference. That’s all!

Some things to watch for…..Some OD tapes (diameter tapes) are marked in 100ths of an inch. Some are marked in 64ths of an inch. On the 64ths of an inch tape, 32/64 would be 1/2″. 16/64 would be 1/4″. 24/64 would be 3/8″. For convenience, you can use a magic marker to mark some of these common, but confusing measurements.

For a 2 1/2 minute video with more detail, click How To Use A Diameter Tape.