Anyone who plans to independently install a water supply system should study the standard sizes of water pipes on the market. This information will be very useful, because only knowing the sections and diameters of the parts that are used in the work, we will be able to select the appropriate fittings and adapters, as well as arrange a connection to household appliances.
Below we will provide general information on pipe dimensions, as well as provide reference data that will facilitate your selection of equipment at the design stage.
Main settings
Key dimensions
Pipes of various materials are used today for laying hot and cold water supply systems.
If you plan to do the installation yourself, then most likely you will use the following varieties:
- Steel.
- Copper.
- Polyethylene.
- Polypropylene.
- Metal-plastic.
Despite the fact that the range of products from each category is quite wide, and the sections are mostly standardized, there are still certain differences. That is why when buying materials for you need to pay attention to the functional parameters of products.
The dimensions of the water pipes are determined by the following values:
- Dn is the nominal diameter.
- Du - conditional passage (internal section, expressed in millimeters).
- Wall thickness (the larger - the stronger the structure, and the higher the pressure it can withstand).
- Outside diameter.
Note! The value of the outer diameter is very important when we are planning a hidden installation of a water pipe and preparing strobes for laying contours. In other cases, it is better to operate with the concept of "conditional passage".
inches and millimeters
Very often, manufacturers indicate the dimensions of water pipes in inches - and a millimeter up or down can cause an insufficiently tight connection:
- When joining products from the same material, such situations rarely occur, but when replacing, for example, steel structures with plastic or copper, you can get into an unpleasant situation.
- The thing is that inches are used to mark the thread that is cut on the outer surface.. And since the wall thickness of different models may vary, there is a risk of error.
Advice! In order not to get confused, it is better to focus not on the outer diameter of the product, but on the value of Dy - it is she who correlates with the inch marking.
The most common dimensions of water pipes in mm and inches are given in the table below:
| Thread, in inches | Conditional passage, in millimeters |
| 3/8 | 10 |
| 1/2 | 15 |
| 3/4 | 20 |
| 1 | 25 |
| 1 1/4 | 32 |
| 1 1/2 | 40 |
| 2 | 50 |
| 2 1/2 | 65 |
| 3 | 88,5 |
| 4 | 114 |
As for practical use, they usually focus on such data:
- For laying internal water pipes, the instruction recommends using pipes with a section from 3/4 inch to 1 1/2 inch, depending on the required throughput.
- Thicker products are usually used for laying risers and arranging water-bearing mains.
dimensions
Metal
Until recently, steel products were the most common type of parts for laying water pipes.
Two parameters are usually indicated in the marking of such elements:
- Outside diameter.
- Wall thickness.
To find out the internal section, it is enough to subtract two wall thicknesses (in millimeters) from the diameter value.
The most popular range of steel structures is given below:
| Outside diameter | Conditional pass | Wall thickness | ||
| Lungs | Standard | Reinforced | ||
| 10 | 17 | 2,0 | 2,2 | 2,8 |
| 15 | 21,3 | 2,5 | 2,8 | 3,2 |
| 20 | 26,8 | 2,5 | 2,8 | 3,2 |
| 25 | 33,5 | 2,8 | 3,2 | 4,0 |
| 32 | 42,3 | 2,8 | 3,2 | 4,0 |
| 40 | 48 | 3,0 | 3,5 | 4,0 |
Despite the fact that the price of the material is not democratic, in some cases copper circuits are used for water supply. Their dimensions are somewhat different from steel products:
Advice! When choosing metal elements for installing a water supply system, it is worth measuring the dimensions of several products from the purchased batch using a caliper. So the accuracy of the determination will be much higher!
Plastic
The sizes of plastic pipes for plumbing, widely used today as an alternative to metal circuits, are also very diverse. At the same time, many manufacturers of polypropylene, polyethylene and metal-plastic parts use their own dimensional grids, therefore, within the same system, it is desirable to use designs of the same brand.
Of course, discrepancies, if they arise, will be insignificant, but for an inexperienced master, they can also be difficult.
The size table of plastic pipes for water supply (polypropylene of different densities) contains information on the most popular models. All dimensions are given in millimeters:
| Outside diameter | PN30 | PN20 | PN10 | |||
| Wall thickness | Internal section | Wall thickness | Internal section | Wall thickness | Internal section | |
| 16 | — | — | 2,7 | 10,6 | — | — |
| 20 | 3,4 | 13,2 | 3,4 | 13,2 | 1,9 | 16,2 |
| 25 | 4,2 | 16,6 | 4,2 | 16,6 | 2,3 | 20,4 |
| 32 | 3,0 | 21,2 | 5,4 | 21,2 | 3,0 | 26,0 |
| 40 | 3,7 | 26,6 | 6,7 | 26,6 | 3,7 | 32,6 |
| 50 | 4,6 | 33,2 | 8,4 | 33,2 | 4,6 | 40,8 |
| 63 | 5,8 | 42,0 | 10,5 | 42,0 | 5,8 | 51,5 |
| 75 | 6,9 | 50,0 | 12,5 | 50,0 | 6,9 | 61,2 |
Of course, when laying communications, other sizes of plastic water pipes can also be used. However, to solve most of the problems that arise when performing normal repairs, the information indicated in the table will be sufficient.
Conclusion
The dimensions of the pipes for the water supply must be observed with the greatest possible accuracy. Even with a deviation of a fraction of an inch, it will be almost impossible to tightly connect two sections of the network or connect a fitting, which means that the reliability of the entire system will be compromised ().
You can study the dimensions and markings in more detail by reading the regulatory documents and watching the video in this article.
