How to properly attach polypropylene pipes to the wall - materials and methods

Polypropylene pipes superior to steel ones in a number of criteria.The blanks can be easily cut to the required size and soldered into the most complex plumbing or heating circuit.

The only drawback is that fastening polypropylene pipes requires special attention. The material is quite plastic and soft, which is why hot water supply and heating pipelines can sag under their own weight.

What are the fastening standards?

It all depends on the work situation. If you are installing plumbing in a private house, in a country house, or an individual heating circuit in an apartment, then the craftsmen will determine the attachment points for polypropylene pipes, as they say, at their own discretion.

For serious projects of laying heating mains and hot water supply lines, a foundation is required, which is best defined by a regulatory document. This is the only way to justify the number of pipe fastening points and, accordingly, include the purchase cost of fasteners in the estimate.

The basis for choosing the number of attachment points can be two documents:

1. Recommendations, tables, calculation formulas given by the manufacturer in the technical data sheet for polypropylene blanks. Usually these are averaged data for pipes of a certain diameter installed on clips.
2. Set of rules SP 40-101-96 dated 09/04/1996 “Design and installation of pipelines made of polypropylene “Random-copolymer””.

The last document can be recommended for professional installers. It contains all the necessary information on polypropylene pipes:

• calculation method for elongation during heating;
• recommendations for choosing distances between fastening points for both horizontal and vertical sections.

You also need to know how to properly fasten polypropylene pipes at turns or in corner areas. You can’t install it at random; moreover, you need to use two types of fasteners – fixed and sliding.

How to attach

The easiest way is to secure a polypropylene cold water pipeline. It is enough to use the recommendations of the pipe manufacturer regarding the distance between the fastening points. The information given concerns mainly sliding types of fasteners at room temperature of 20 ℃.

One of the outer side fastenings on the wall, from corner to corner, is fixed. This is usually a clamp or self-tightening clamp. At other points, sliding fasteners are installed.

The process of attaching polypropylene pipes for hot water supply or heating looks somewhat more complicated:

1. Draw up a diagram for laying the pipeline along the wall.
2. According to the recommendations of SP 40-101-96, the number of fastening points is calculated according to the recommended distances between fasteners for a certain water temperature.

Additionally, you need to calculate the dimensions of the compensation loop in the corners, taking into account the installation of fixed and sliding supports.

For polypropylene pipes, two types of fasteners are used - clamps and clips.The first is a steel clamp consisting of two halves. One of them has a post screwed or welded to it, usually a pin or dowel. With their help, the clamp is screwed into the plug driven into the wall.

Fastening a polypropylene water supply looks like this:

1. Mark the fastening points on the wall and drill holes for the plugs with a hammer drill.
2. Wrap the plug, pin or dowel of the clamp inside.
3. Place polypropylene pipes on the supports, install the mating part of the clamp and secure the fasteners with a screwdriver.

Almost all models clamps equipped with internal rubber gaskets. Their use is mandatory. Soft rubber compensates for inaccuracies and deviations that occur when installing clamps on the wall.

Installation of clips is also done using plugs and self-tapping screws. They can be self-locking or tape-clamped. In the first case, no additional actions are required - just press the polypropylene pipe on the clip until the side mustache clamps snap into place.

In the second case, the pipe must be laid on a plastic support and the pressure tape must be tightened.

Before assembling the water supply, it is necessary to determine the distances between the fasteners.

Distance between fasteners

The number of attachment points must be determined separately for horizontal and vertical sections of the polypropylene pipeline.

For the vertical section, the attachment points are placed at a distance of no more than 100 cm for polypropylene pipes with a diameter of up to 32 mm; in other cases, the gap between the supports can be increased to 150 cm.

How is the distance between fastening points calculated?

For a horizontal section of a polypropylene pipe, the recommended distance is selected from table 2.1 of the Code of Practice SP 40-101-96.

The recommendations concern only the minimum distance between supports. If necessary, the number of attachment points can be increased and even redistributed unevenly. But the minimum distance must correspond to the recommended values.

Last check before assembly

Upon completion of the calculation, you need to check the correct location of the selected attachment points relative to the fittings, couplings, and taps. Initially, the polypropylene pipe will be installed cold. In working condition, the hot water supply system pipeline heats up to at least 60-70 ^OC. As a result of thermal expansion, the line will lengthen.

All elements embedded in the main - tees, taps, bends with fittings - will also move a certain distance to the left or right, depending on where the fixing support and compensation loop are installed. Therefore, the coupling, tap, triangle with a fitting for a flexible branch must be located from the fastening at a distance greater than the pipe extension.

The extension of the pipeline cannot be neglected, even if a conventional PN30 SD6 pipe blank is supplied for hot water (which is essentially wrong) for reasons of economy. The increase in length will be significant, so cut-in fittings may break the fastener.

For example, a polypropylene pipe 6 m long, when heated from 20 ℃ to 70 ℃, lengthens by 52-55 mm. If the clamp or clip is closer than 5 cm from the coupling, the fastener will be torn from the wall.

The amount of elongation can be determined using a nomogram.The magnitude of the temperature change during heating is indicated vertically; the length of the section is selected along the graph line. Then horizontally you can determine the lengthening of the section in millimeters.

How to calculate the dimensions of a loop on a polypropylene pipe

Thermal expansion is considered the most serious disadvantage of polypropylene. Even if you use pipe blanks with a reinforced layer of aluminum or fiberglass, the problem of elongation will not disappear.

For example, a six-meter piece of reinforced polypropylene from the example above, when heated to 70 ℃, will increase in length not by 5 cm, but by only 1 cm. But this is enough to break the fastener support or deform the threaded fitting on the heating radiator.

Therefore, a compensation loop must be installed in the circuit. It is best to make an expansion joint in the corner. Movements of 10-12 mm are practically invisible to a prying eye, and in general the system looks more aesthetically pleasing than installing a ring or a U-shaped compensator.

Section length L_k pipes with diameter d is determined by the formula L_k=25(d∆L)^1/2, ∆L – the amount by which the workpiece was elongated at maximum heating at T = 90-95 ℃.

One fastening point must be fixed, and the second must be made according to a sliding pattern. Sometimes, to block movement, the seat on the pipe is welded on the left and right with two couplings.

Polypropylene pipes with a diameter of up to 32 mm can be installed with a homemade compensator ring. The radius of the annular loop along the center line is calculated as the diameter of the pipeline multiplied by the coefficient K=8.

When is it better to use fastening clips?

This type of fastener is used mainly for pipelines of small diameter - from 16 mm to 50 mm.Large-diameter polypropylene lines cannot be held with clips due to their low fastening strength. Pipes less than 16 mm are fixed to the walls with loops.

Clips are ideal as sliding supports. The design of the fastening is such that the outer surface of the pipe contacts the ring only through plate-like protrusions. Even with a slight inaccuracy in the installation of fasteners, no additional distorting load will appear on the pipeline.

Clips are practically not used as fixed supports due to their low strength. If it is not possible to purchase a special stationary support or install a clamp, then it can be replaced with clips for fixing copper pipes.

Certain models of clips, for example, with a tape and a lock, are convenient to use for fixing polypropylene pipes covered with soft thermal insulation.

The clip fastening is made of cast polypropylene, so the coefficient of thermal expansion does not differ from the material of the pipeline. Accordingly, when heated, the pipe does not wedge inside the clip.

The average price for one clip is 10 cents; fasteners are usually sold in packs of 10 or 20 pieces.

When is it advisable to use clamps for fastening

The advantage of this type of fastener is its versatility. Clamps can be used to secure both metal and plastic pipes. It is permissible to make clamp supports both in a stationary version and in a sliding version. In the first case, soft rubber gaskets are installed inside, in the second - a Teflon or split polypropylene ring.

Metal clamps can withstand significant axial and radial loads. The fasteners are not afraid of ultraviolet radiation and low temperatures.Therefore, all external pipelines are installed only on clamps. The service life of the fastening is several times higher than that of propylene pipes.

The disadvantages of clamp fasteners include:

• high price - from 50 cents per piece;
• the clamp is designed for a polypropylene pipe of a certain diameter;
• increased installation complexity.

The reliability of the clamp largely depends on the quality of the assembly. During the manufacturing process of the fastener, a stud or dowel is usually welded to the lower half ring by welding. If the installation is inaccurate and if there are strong blows with a hammer when pushing the dowel inside the plug, the welding seam may peel off or crack. Accordingly, under the weight of the polypropylene pipe, the support will simply collapse.

How to fasten polypropylene heating and water pipes in a hidden way

Due to its high chemical resistance, polypropylene pipelines can be laid directly in walls, under plaster, or directly into the ground. In any case, before laying the polypropylene pipe, a groove or groove is first cut out with a hammer drill. The dimensions of the cavity should be twice as wide and deeper than the transverse dimension of the main.

Before sealing, it will be enough to secure the cold water supply to the wall with a temporary fastening - a wire or plastic loop. As soon as the initial sections of the groove are plastered, it can be removed. In an unheated room or when laying a water supply system in the ground, the pipe is covered with a heat-insulating polyethylene foam cover.

Polypropylene pipes for hot water supply and heating are placed in plastic boxes. In the same way, hidden installation is carried out in the walls and behind plasterboard cladding.Often, fasteners for polypropylene hot and cold water pipes can be installed in one channel, as well as wiring can be laid in a protected corrugation.

When laying polypropylene pipes in the ground below the freezing depth, it is better to use an additional PVC sewer channel. To prevent condensation from accumulating inside the protective polyvinyl chloride shell, stakes are driven into the bottom of the trench, and the PVC pipe is suspended using wire fasteners with a certain slope to drain moisture. A sand cushion is poured onto the bottom. After this, you can lay a polypropylene pipeline inside and fill the trench with soil.

Fastening polypropylene lines must provide both a loose fit in the axial direction and rigid fixation in the radial direction. Due to temperature fluctuations, pipes always experience additional loads, so the reliability and long service life of the pipeline depends on the correct choice of type of fasteners.

The main secrets of installing polypropylene pipes. Master class on fastening polypropylene pipes: video.

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