Sizes of plastic pipes for water supply: the choice of a suitable diameter

If you are faced with a need replacement of the water supply system in the apartment, then you will have to purchase suitable parts - pipes and fittings. After the difficult question of choosing a material, the main thing you have to think about is the dimensions of the water supply elements.

Characteristics that determine the size of pipes for water supply

Speaking about the size of the pipes, they usually mean a combination of the following parameters.

• Outer diameter - usually indicated by the manufacturer.
• Diameter inside - is an important characteristic for parts of the plumbing system, measured in inches. For pipes and fittings connected to each other, it should not differ.
• Nominal diameter (DN) - is the nominal value that is used in the installation of all parts of the water supply. It is an averaged parameter close in value to the diameter of the lumen.
• The wall thickness of the product.
• Length of the product.

Matching pipe diameters

Quite often, a water supply system is a combined system that includes elements from different materials. Difficulties may arise here, since the diameter of steel structures is indicated in inches and that of plastic products in millimeters. In order to choose the right sizes correctly, you can use specially designed tables. If you need to connect the steel part of the water supply with plastic elements, then the table of correspondence of the diameters of steel and plastic products will help you.

1 inch corresponds to 25.4 millimeters.

Water throughput

The diameter of the pipes for the water supply system has a direct connection with such a concept as throughput. It is determined by the passage of a certain volume of water over a certain period of time. For example, a pipe having a clearance of 25 millimeters can pass a volume of water reaching 30 liters in a minute.

The capacity is taken into account when calculating the dimensions of the parts of the water supply system and the pressure of the liquid. It can be determined in three ways:

1. Using formulas that use system parameter measurements. Such calculations are quite complicated, so they are used only by specialists.
2. Using tables for a specific type of material.
3. With the help of programs designed to optimize water supply systems.

You need to know this: one of the advantages of plastic pipes, unlike steel or cast-iron pipes, is to maintain a constant value of throughput throughout the entire service life.

Choosing the diameter of plastic pipes

The optimal size of the elements of the water supply system depends on many factors:

• water pipe lengths;
• the number of joints and joints;
• number of turns;
• the number of points of water intake;
• water pressure in a particular system.

The good news for non-professionals who install their own water supply is the ability to abandon complex calculations and use standard solutions.

As a determining parameter, you can take the length of the water supply system:

• for systems having a length not exceeding 10 m, pipes with a clearance of 20 mm are more often used;
• for 10-30 meter systems, products of 25 mm diameter are usually taken;
• lengths greater than 30 meters require the use of a 32 mm diameter.

If we are talking about intra-apartment wiring, then everything is much simpler. Since the water supply in the apartment has a small length, in most cases products with the following internal diameters are suitable here:

• 15 mm or half an inch;
• 10 mm or 3/8 inch.

For the riser, choose the following sizes:

• 20 mm or 3/4 inch;
• 25 mm or 1 inch.

A larger diameter may be needed in the following cases:

1. If the water supply system has a complex structure, having a large number of turns, joints and is characterized by pressure inconsistency;
2. If water is constantly used in large quantities.

What threatens the wrong pipe size?

If the installed water system components have the wrong diameter, this can cause the following problems:

• Increased system pressure will create additional load, leading to accelerated wear and increase the likelihood of breakouts and breakdowns.
• The water in the pipes will make noise - the buzz is also caused by pumping pressure.
• A significant decrease in pressure when taking water at one of the points - for example, when you turn on the shower in the bathroom, the tap water in the kitchen will flow in a thin stream.