Dimensions of polypropylene pipes - what to consider when choosing, table

The basis for planning communications in private households has always been and remains the calculation of the flow rate of the transported medium and the cross-section of the pipeline. Only on the basis of calculated data can you select the sizes of polypropylene pipes from the existing range. Unlike steel ones, polypropylene ones differ both in the properties of the polymer and in the recommended scope of application. What other features do they have?

What determines the dimensions of polypropylene pipes?

Polypropylene pipe blanks were designed for a specific use case. Polypropylene pipes have never been universal - they were not combined into a single range, as in the case of steel ones. At best, you can find a size chart for the recommended type of communications. Therefore, it is not enough to know the optimal dimensions of polypropylene pipes in mm for a specific liquid or gas flow.

When choosing sizes you need to consider:

• material, a type of polymer based on a polypropylene matrix;
• pressure and temperature of the working environment;
• type of environment being moved;
• method of connecting pipe blanks. As the transverse size increases, the number of technical problems increases proportionally.

There is one more nuance.The throughput and diameter of the pipeline obtained during the calculation for the project will always differ from the internal size of polypropylene pipes. The latter are produced with a certain diameter pitch. Therefore, you need to select a workpiece with the closest, most suitable transverse size. For example, select from a table.

This is necessary so that the throughput does not decrease below critical, and not to spend money on purchasing more expensive large-diameter polypropylene pipes.

Dimensions depending on material of manufacture

For the manufacture of polypropylene-based pipelines, several types of polymer compositions are used. Pure polypropylene is used to a limited extent due to its low mechanical characteristics and low resistance to heat, active oxygen and ultraviolet radiation.

PPR

The most common material. This is a random copolymer of polypropylene with ethylene and polyethylene. Thanks to high-temperature directional polymerization, a dense, durable, heat-resistant structure is formed. This is the most durable brand of polypropylene.

Workpieces marked PPR or PP-R are used for:

• heating;
• hot and cold water supply;
• heating systems such as underfloor heating.

The standard size range is 16-250 mm. The material is perfectly processed and soldered with hand or machine tools.

P.P.H.

This is almost pure polypropylene with additives that prevent secondary polymerization, aging and delamination. The plasticity of the material is lower, the rigidity and strength are higher. Low density and high water resistance. Therefore, large cross-section pipes are made from homopolypropylene:

• pressure type with diameters 63, 90, 110, 200, 250, 315 mm;
• non-pressure type with diameters 200, 250, 315, 400, 500 mm.

Homopolypropylene pipe blanks do not adhere well and have low impact strength. Therefore, the assembly of large-diameter sections of free-flow water pipelines is carried out mainly mechanically using rubber seals.

P.P.S.

Copolymer of polypropylene and polyethylene. Unlike other brands of polypropylene matrices, it has low thermal resistance; heating to a temperature of no more than 80 ℃ is allowed. Can be used at low temperatures, down to -20 ℃.

It is used primarily for medium-section water pipes laid in unheated rooms and in open areas. The outer size of polypropylene pipes is 25-225 mm.

PPB

This type of material for polypropylene pipes is the result of the joint polymerization of ethylene and propylene. Only, unlike PPS matrices, the structure turns out to be block-based. Individual microblocks of PPB-polypropylene, characterized by high strength and chemical resistance, are interconnected with a mixture of PP and PE with a lower degree of polymerization.

PPB polymer was developed as an effective replacement for PPH brand polypropylene pipes. Most manufacturing companies producing sewer pipes and fittings are switching from PPH to PPB. The dimensions of pipe blanks are 55-500 mm.

How to select pipe sizes based on system pressure

With rare exceptions, pipe blanks are purchased “blindly”. The customer, master or home owner simply informs the manager that they need polypropylene pipes “for soldering” or for assembling water supply, heating, sewerage systems. The seller offers the product in stock with his comments. None of the participants in the process even tries to understand the markings.

The first thing you need to pay attention to is that the grade of polypropylene should be PPR - random copolymer. There may be several options for marking - PPR, PP-R, PP-RCT, all of this is practically the same material.

For lines with increased internal pressure, a random copolymer is used. Therefore, the presence of one of the marking options on the workpiece indicates that it is definitely suitable for highly loaded pipelines, no matter whether the size is 16 mm or 250 mm.

Next you need to check the maximum pressure value - it is indicated on the marking as a combination of letters and numbers:

• PN10;
• PN16;
• PN20;
• PN25.

The numbers indicate the maximum pressure (Bar) at operating temperature. The first three are used for non-hot water. The last two are for transporting hot water or liquid media under pressure, at temperatures up to 95 ℃. Working conditions are more difficult, so the walls are made multi-layered and reinforced. Their thickness increases, and the outer size of the pipe blank increases.

Important size characteristics

Another parameter is called the SDR index. It characterizes the ratio of the outer diameter of a polypropylene pipe to the wall thickness. Usually indicated as a number on the outer surface of the workpiece, next to the marking.If there is nothing, then the index can be calculated independently. It is enough to measure the diameter and wall thickness of the workpiece with a caliper, and then divide the first value by the second.

Why is this necessary? This is the most important indicator of the load capacity of a polypropylene pipeline. For example, most pipes of the PN20-25 class have an index no higher than 7.4. Conventional pipe blank PN10 – as many as 11 units. The higher the SDR index, the lower the mechanical strength of a product of any diameter.

Dimensions depending on application

The good processability of cast polypropylene and simple production technology are causing the gradual displacement and replacement of polyethylene pipes with polypropylene pipes. In addition, polymers of the PPB, PPH, PPR brands are considered safer in comparison with their closest competitors - polyvinyl chloride and polyethylene.

Dimensions of polypropylene pipes for ventilation

The standard diameter of ventilation ducts is 110-200 mm. This is enough to remove polluted air through the hood in the kitchen, bathroom, or in any residential or non-residential area of ​​a house or apartment. Ventilation systems for office premises are equipped with pipes up to 250 mm.

Installation is performed by mechanical pipe-socket assembly. It will not be possible to replace ventilation based on RRV pipes with polyethylene or polyvinyl chloride.

Polyethylene air ducts are prone to electrification and the accumulation of dust plugs that clog filters and heat exchangers. PVC should not be used on air ducts for fire safety reasons.

In addition, PPV pipes have greater rigidity than blanks made of vinyl or polyethylene. For example, it is almost impossible to crush the walls of a standard 16x2.2 mm polypropylene pipe blank with your fingers. Whereas similar products made of polyethylene or vinyl wrinkle easily.

That's why ventilation made from polypropylene with a diameter of up to 1200 mm with an SDR index of tens of units. Under load, the walls do not wrinkle and withstand any pulsations and fluctuations in air flow.

Dimensions of polypropylene pipes for sewerage

For waste and sewer systems, pipes made of PPH polymer are used. The material's chemical resistance is almost equal to PVC, but it has higher water resistance and, most importantly, wall rigidity.

This means that propylene sewer pipes can be manufactured with a high SDR index:

• the weight of the pipe blank is less, which means the sewage system will be cheaper;
• the joint on the rubber seal will not leak;
• locks at the joints of polypropylene pipes practically do not have such defects.

For domestic sewers, PPH blanks with a diameter of 25, 50, 110 mm are used. To drain sewage from the house, pipes measuring 300-550 mm are used.

Dimensions of polypropylene pipes for water supply and heating

For piping a boiler or distributing a centralized heating system, hot water pipes of the PPR brand, class PN20, SDR index 6-7 units are used. Dimensions – 20-40 mm.

PPR - PN10 with an SDR index of more than 10 is installed on the return line feeding the main or water supply. The cross-sectional dimensions of the pipelines are determined by the second water flow. For the hot section, pipes reinforced with fiberglass or aluminum foil are installed.Otherwise, the soldered joint between the fitting and the hot propylene wall under pressure may leak.

There are many models of PPR pipes on the market. Despite the fact that pressure polypropylene pipes of different brands are made of almost the same material, and there are differences between them in the range of sizes. Any manufacturing company has its own catalog of polypropylene pipe sizes; it will help you make a choice.

We can recommend, as an option, the following models:

1. Pipes marked PVPP-RCT UNI are easily distinguished by their characteristic green longitudinal stripe. Transverse dimensions - from 16x2.2 mm to 250x22.7. It is believed that hydraulic losses in water pipes of small cross-section are less than in analogues.
2. Pipe blanks marked PVPP-RCT FASER with an orange longitudinal stripe, cross-section 20x2.8 mm, are most popular for supplying hot water under pressure up to 25 bar. It features a coefficient of thermal expansion reduced by more than three times.
3. PVPP-RCT is designed for high temperature and pressure of the internal environment. Dimensions from 20x2.8 mm, PN index can exceed 25 units. Marked with a red stripe.
4. For main water supply, PVPP-R CT FASER pipe blanks are used. The input diameter can be 40x3.7 mm or more.
5. At the entrance to the apartment, polypropylene pipes of the PP-RCT brand, with a diameter of 25x4.2, are used. The NOT series for hot water and the CLASSIC series for cold water.

You can assemble a water supply using propylene pipes of any type and size. But it is still better to install pipe blanks of the appropriate size and cross-section. This will save money, and the water supply will not make noise or hum due to fluid fluctuations in the flow.

Special cases

Polypropylene pipes are widely used as a substitute for aluminum or steel profiles.From pipe blanks with an outer diameter of 25 mm, you can easily solder the frame of a small greenhouse with a base size of 200x400 cm. It is better to use polypropylene sections with an SDR index of at least 5; the wall thickness is 5.1 mm. This is enough to bend the arched vault and screw self-tapping screws into the wall to attach crossbars or fix the stretched film.

From the polypropylene scraps remaining after assembling the heating circuit, you can make heated floors for a loggia or balcony. The room itself will need to be thoroughly insulated along the walls, ceiling and floor. Foiled polyethylene foam is laid under the pipes. For the heating circuit we use polypropylene blanks of the PPS brand, 25 mm in size and SDR index equal to 10. Thin walls conduct heat well, and the material is not afraid of freezing down to -20 ℃.

How pipe sizes are taken into account when welding

Pipe material with a transverse dimension of up to 63 mm is soldered using a hand soldering iron. Any brand of polypropylene for pressure water pipes is spliced ​​using polypropylene couplings heated on the nozzles of an electric soldering iron. The quality of the connection in all cases is high.

The only thing is that you need to be careful when soldering pressure pipelines from PPR blanks, with an outer diameter of 20 mm and an SDR index of 5. The wall thickness is 4.1 mm, the clearance distance between them is only 12 mm. If you overheat the material or apply too much force, then flash or burr can completely block the passage inside the pipe.

There are industrial soldering irons that can be used to weld fittings up to 110 mm in size and larger.

The soldering of a contour made of aluminum-reinforced polypropylene must be additionally prepared by trimming the outer and aluminum layers.Otherwise, the pipe diameter will be too large to fit into the hole in the coupling or tap.

The range of sizes of polypropylene pipes allows you to choose the appropriate diameter for water pipelines any performance. The soldering technology has been proven even for large sections, so problems with assembling heating and water mains, as a rule, do not arise.

Polypropylene pipes for water supply and heating systems. Types and benefits: video.

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