Hose and Fittings Measurements: Size

Understanding STAMP’s Hose and Fittings Measurements: Size

Hoses and fittings may seem like small parts of a large and complex piece of machinery, but they’re incredibly important. So important, in fact, that getting them wrong can lead to some disastrous consequences.

At the very least, wrongly-sized hoses and fittings speed up the rate of equipment failure. They can also put the safety of a worksite at risk. For all of these reasons, it’s important to specify the precise measurements of hoses and fittings long before they reach the jobsite.

Most people have heard the principle: “Measure twice, cut once.” But few people put that idea to practice every day. Thanks to a new acronym – STAMP –measuring hoses and fittings is easier than ever before.

How STAMP works

STAMP stands for:






All of these factors must be carefully weighed in order to find the right hoses and fittings. And STAMP is helping businesses all over the country ensure they buy the perfect hoses and fittings for the job – no matter what that job may be.

STAMP was created by Parker Hannifin, a global leader in fluid connections and hosing. As experts in the business, their goal is to connect customers with the right equipment every time.

For the next several weeks, we’ll be explaining the STAMP measuring process in detail. Today, we’ll show you exactly how to measure one of the most important qualities of hoses and fittings: the Size.

S – How to measure Size

Parker Hannifin uses a system of measurement called dash numbers to indicate hose and fittings size. Dash numbers – also known as dash sizes – tend to be the easiest and most accurate way to measure any types of hoses and fittings.

To find the dash size, simply take a measure of the hose’s inner diameter in sixteenths of an inch. This measurement is universally used by the fluid power industry today. Take a look at the diagram below to understand exactly what parts of the hose to measure:


If you don’t know the hose size, and you don’t want to cut into a hose to measure its inner diameter, then you may be able to find it on the layline.

However, if the original printing on the layline has worn off, then you will need to cut the hose and measure the inside diameter. Before cutting the hose, be sure to measure the length of the overall assembly as well as the fitting orientation.

Note: When dealing with SAE 100R5 hose, dash size measurements are different. Most other hydraulic hoses are measured using the inside diameter (also known as the ‘I.D’ of the hose) as shown in the above diagram.

Why size is important

As you probably already know, size is extremely important when it comes to hoses and fittings. But few people realize just how important size is. An improperly sized hose will not reach the proper flow velocity. If the hose is too large, the flow velocity will be sluggish and weak. If the hose is too small, the pressure can increase to a point where the system bursts or leaks.

Next, we’ll explain exactly how to measure the Temperature of hoses and fittings in order to ensure a perfect fit.

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