How to choose the right diameter of flexible hose - what to look for when purchasing

Most buyers purchasing plumbing hose, do not think about the diameter of the flexible liner. At first glance, there is not much difference, especially since the connectors look almost the same. But the transverse size of the sleeve is important; it must be taken into account when connecting household appliances.

What you need to know about choosing the diameter of a flexible liner

To connect plumbing fixtures, faucets and household appliances, soft braided hoses or flexible metal bellows-type hoses are used. In both cases, union nuts or fittings are used for connection.

The diameter of the nut on a flexible liner made of food-grade heat-resistant rubber comes in several sizes:

• 1 inch - used to connect consumers with high water consumption, for example, a bathtub or geyser;
• 3/4 and 1/2 inches - most plumbing fixtures and household appliances are connected;
• 3/8 inch - connects certain models of mixers and taps.

To connect a braided rubber hose, a fitting with a thread of reduced diameter is used, usually size M10x1 or M9x1, the length of the threaded section is 18 mm or 35 mm.

On a flexible bellows-type hose, the size of the fitting nut can be from ½ inch to 2½ inches.

In the case of metal corrugated hoses, the internal and external diameters differ by wall thickness.Typically, stainless steel with a thickness of 0.3 mm is used to make a bellows. Therefore, the throughput can be estimated by the transverse size or the inlet cross-section.

Another thing is a flexible rubber hose made of food-grade EPDM rubber. In this case, the wall thickness for hoses of different sections can be 1.5-3 mm. Accordingly, different internal diameters of flexible hoses are obtained. As a result, the conditions for safe operation change, and most importantly, different water consumption results.

Internal diameters of rubber liners of different sizes

The design of the flexible connecting hose is such that fixing nipples are installed at its ends. Essentially, it is a tube with a rim at the end. The nipple is made of brass or galvanized steel. With its help, a nut is fixed at the end of the rubber hose.

Since the nipple is pressed inside the hose, the throughput of the line will largely depend on the internal diameter of the hole in the brass tube.

For models of well-known brands, information about the dimensions and diameters of the hose is indicated in the product passport. High-quality products will have this document, otherwise the product will not pass certification and will not be allowed to sell.

For example, for products of the well-known trademark “STOUT” (Italy), the following information on eyeliners is provided:

• for models with 3/8" and 1/2" nuts, the internal and external diameters of the sleeve are 8.5 mm and 11 mm, respectively. The through hole in the nipple is 6.2 mm;
• for a 3/4″ nut or fitting – the internal and external diameters of the sleeve are 19 mm and 25 mm. The hole in the nipple is 15 mm;
• for a nut with a 1” thread, the diameters are 25.5 mm and 32 mm. The hole in the nipple is 21 mm;
• For models with a 1 ¼” nut, the internal and external dimensions are 32 mm and 40 mm. Nipple – 27 mm.

This is enough to estimate the approximate water consumption and make a choice of a specific hose model. But when purchasing rubber hoses, in addition to the cross-section, you have to take into account the operating safety conditions established by manufacturers of flexible hoses for their products.

How to choose the diameter of a flexible liner based on its type

Even the highest quality rubber hose braided with stainless steel wire and reinforced with polyester threads will sooner or later fail if installed incorrectly.

Restrictions

Two conditions related to diameter:

• It is impossible to install a hose in a metal braid if the bending radius is less than five transverse dimensions. If, according to technical conditions, there is no other way to place the hose or choose a model with a smaller pipe diameter, you need to use a supply hose with an angle fitting;
• Do not install short hoses on household appliances if vibrations or vibrations occur during operation. In this case, the ratio of length to diameter must be at least 100.

When replacing hoses with an M10x0.5 fitting on a kitchen faucet, it makes sense to use brass adapter and a larger diameter hose. In this case, it is possible to install a flexible liner with minimal risk of crushing or tearing the rubber under the sleeve.

Consumption

More often, a supply hose is chosen for a specific type of equipment. You just need to know the length and size of the union nut. As a result, for the compact tank, the first available sleeve of a suitable length with the smallest nut size, screwed onto the fitting of the drain mechanism, is purchased.

It is believed that the smaller the transverse size, the higher the flexibility of the connecting hose, the easier it is to hide it. In this case, it is better to choose a long hose for a fitting-nut of at least ½”.

Taps or mixer taps in a bathroom sink will require a large capacity, so use models with a ¾” nut.

Often, when choosing a suitable connector hose, it is necessary to know exactly the water flow. In this case, you can calculate the value yourself or use data from an online store.

The most reliable information on water consumption will be taken from the passport for flexible hoses:

• for models with a 3/8" or 1/2" union nut, the flow rate of the nipple on the spout is 28 l/min;
• for models with a 3/4” fitting nut, the flow rate is 200 l/min;
• for a 1” hose, water outflow – 280 l/min.

Water flow is calculated at an inlet pressure of 3 At (3 bar). If you use data from an online store, you should always clarify at what pressure the water capacity is indicated.

Using the given data, you can calculate the water consumption for bellows. You just need to calculate the coefficient by how much the cross-sectional area of ​​the corrugation is larger or smaller than one of the rubber sleeves. The water flow through the corrugated hose will change proportionally.

How to independently determine the diameter of a flexible liner and what else to look for when purchasing

It is often necessary to install a previously used hose on plumbing fixtures. Branded flexible hose lasts a long time and does not rot, so there is no point in throwing away the hose if it can still serve for 5-7 years. The only problem is that the passport or certificate was not preserved. You will have to determine the diameter manually.

Three ways to determine:

• measure the nut size with a caliper and convert the value to inches using the metric and inch scale conversion table;
• measure the holes at the entrance to the nipple. Knowing the size, you can determine which model it corresponds to;
• measure the outside diameter, then subtract the braid thickness. We obtain the outer size of the rubber pipe, from which we can determine the diameter of the flexible line.

In practice, things are usually simpler. They take a hose of unknown diameter and compare it with those installed on the equipment. In any apartment or house there are several flexible connections that can be used as a sample.

Paying attention to the little things

When purchasing flexible eyeliner, you need to be careful. Even if the pipe is sealed in plastic packaging, this does not prevent you from carefully inspecting it.

What to do:

• feel the braided pipe with your hands. Make sure that there are no hernias or bends on the rubber that have formed during long-term storage in a bent state;
• inspect the braid. If it is made of nylon, then the color of the threads should be bright, without stains or breaks. If the outer sheath is made of metal wires, then there should be no broken barbed ends;
• inspect the nickel coating. In high-quality products, nickel looks the same over the entire surface, without gray or yellow spots. If brass is exposed somewhere on the nut, even if it’s just a barely noticeable scratch, then it’s better to discard such a hose.

After purchasing, you need to bend the liner along the radius approximately as it will stand on the plumbing or on the tap. Make sure that the rubber tube is not pinched, blocking the internal channel.

How to install and operate flexible hoses of various diameters

The eyeliner can be installed in two ways.In the first case, the hose connects the outlet on the water pipe with a fitting on the locking mechanism of the tank or boiler inlet. In this case, use a flexible line with two nuts at the ends.

To install, simply place the winding on the fittings, lay the gasket, and tighten one of the nuts. Align the position of the flexible hose, then place the gasket and tighten the second nut. If a drop appears after turning on the water, tighten it a quarter turn with a wrench.

Installing flexible hoses with ball valve or valve. In this case, a hose with a nut and a fitting at the ends is used. We wrap the fitting with packing tape and tightly wrap it inside the ball valve. Install the tap on the pipe. Lastly, tighten the nut onto the fitting of the tank or boiler. To prevent the hose from twisting when tightening, it is secured with an open-end wrench. Do not use pliers or pliers.

Installation of flexible connecting hoses on the mixer is carried out in the same order. First, you need to screw the fittings with M10 threads into the body of the tap, then install the mixer on the washbasin or sink, after which you can attach the nut to the water supply outlet.

Operational problems

Troubles with flexible hoses arise when the flexible hose is defective or incorrectly installed. The most common case is that the radius of curvature is too small. In this position, the rubber is deformed on the sleeve and cracks appear. To avoid this, you need to use a flexible line of small diameter, at least one meter long. Even with an average water pressure of 1.5 At, the flow rate through a ½” flexible connection will be at least 12 l/min.

The second most common case is water leaking from the back of the nut from the gap between the wall and the sleeve. It is treated by pressing the nipple into the rubber using a wooden mandrel and a hammer. At the same time, you can check the diameter of the gasket.

The diameter of the flexible hose can always be read from the certificate sheet glued under the nut. The information is minimal, but it is enough to choose the right size. All that remains is to install the hose correctly.

Flexible eyeliner, what to look for when choosing: video.

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