In the field of plumbing, it is generally advised to know the proper sizes for fittings and pipe accessories. Indeed, choosing the wrong size can lead to leaks, reduced system performance, or even material damage. But how can you tell if a fitting is size 12x17 or 15x21? In this article, we will look at different methods to determine the exact size of your plumbing fittings.
Understanding the dimensions of plumbing fittings
Before you can determine whether a fitting is size 12x17 or 15x21, it is important to understand how these measurements are expressed. The dimensions of plumbing fittings are usually shown by two numbers separated by an "x". The first number corresponds to the outer diameter (OD) of the pipe, while the second number indicates the thread pitch, that is, the distance between the threads on the threaded part of the fitting in millimeters.
For example:
- A 12x17 fitting will have an outer diameter of 12 mm and a thread pitch of 17 mm.
- A 15x21 fitting will have an outer diameter of 15 mm and a thread pitch of 21 mm.
Thus, to know if a fitting is size 12x17 or 15x21, you need to measure these two aspects of the fitting: the outer diameter and the thread pitch.
Using a caliper to measure the dimensions
The most accurate way to determine the size of a plumbing fitting is to use a caliper. This measuring tool allows you to precisely assess the outer diameter and thread pitch of fittings, ensuring you choose the right size for your installation. Here is how to use a caliper to measure a fitting’s size:
- Open the caliper by sliding its movable part until it can be placed around the fitting to be measured.
- Place the caliper around the outer diameter of the fitting, making sure to position its fixed part firmly against the outer edge of the fitting.
- Slide the movable part of the caliper until it is snug against the other side of the fitting’s outer diameter.
- Read the measurement shown on the caliper and note the first number (outer diameter).
- To measure the thread pitch, place the caliper on the threaded part of the fitting and measure the distance between the peaks of two consecutive threads.
- Note the second number (thread pitch).
Once these measurements are taken, you can compare the results to the standard dimensions of 12x17 and 15x21 fittings to determine the correct size for your plumbing project.
Checking markings on fittings and pipes
In some cases, the dimensions of fittings may be directly marked on their surfaces. This marking can take the form of raised lettering or a label stuck on the fitting. If so, you can simply read this information to know the exact size of the fitting.
Likewise, if you have already purchased pipes intended to be connected by these fittings, they may also display their size on their surface. You can thus verify that the size of the fittings matches that of the pipes to ensure a successful and trouble-free installation.
Taking standards and materials into account
When choosing fittings for your plumbing system, it is essential to consider the applicable standards as well as the materials used. Fittings can be made from various materials such as copper, stainless steel, plastic, or brass. Each material has its own characteristics and benefits, so it is important to select a fitting suited to your project and compliant with local plumbing regulations.
Measuring the sanitary fixtures to be connected
Finally, another way to determine the size of a fitting is to measure the sanitary fixtures to which they will be connected. Indeed, in some cases, the dimensions of fittings may differ from those of pipes and other plumbing system elements. By precisely measuring these fixtures (for example, the inner and outer diameter of a shower mixer or the distance between threads on a washbasin trap), you can more easily select the right fitting to achieve a watertight and efficient connection.
In summary, to know whether a plumbing fitting is size 12x17 or 15x21, you should accurately measure its outer diameter and thread pitch using a caliper, check any markings on the fitting or pipes involved, and take into account legal requirements regarding standards and materials.
