Polypropylene pipes and fittings: types of PP products for pipeline assembly and connection methods
New technologies are changing the idea of strength and reliability.Not so long ago it seemed that it was impossible to replace a metal pipe. However, now the most common type in the plumbing market are polypropylene pipes and fitting for them and also fittings. The assortment is large, it is important to know how to choose. Do you agree?
You will learn everything about the technological features and technical characteristics of PP products from the article we presented. We will provide guidelines according to which pipes and connectors should be selected. Compliance with our recommendations is a guarantee of selecting the ideal material for pipeline construction.
The content of the article:
Types of PP pipes
According to their design characteristics, PP pipes are divided into two types:
- solid;
- reinforced
Both types have a set of both positive and negative characteristics.
Pros and cons of solid products
One-piece long products marked PPR are lightweight, durable and relatively inexpensive. The pipeline made from them easily tolerates freezing and thawing without changing the structure.
At the same time, a significant disadvantage is the low melting temperature threshold inherent in thermoplastics - 175⁰. The beginning of softening occurs already at 135⁰.
Even if the water temperature in the system is stable and does not exceed 95⁰, but the pressure is high, the combination of these two factors can lead to a gradual decrease in the integrity of the material.
The obvious conclusion is that it is better not to use solid PP pipes for transporting very hot water. For water supply devices They are quite suitable with drinking or technical cold water. Polypropylene does not affect the composition of water.
A special place in the category of solid PP pipes is occupied by modified polypropylene labeled PPs - the highest quality material. It is polyvinyl sulfide with a unique molecular structure. The diameter of PPs pipes is from 20 mm to 120 cm. They are universally used.
Reinforced PP pipes
Reinforced pipes differ from solid pipes in having a lower coefficient of thermal expansion. The reinforcing frame included in the pipes is made of fiberglass or aluminum foil.
Fiberglass frame is a more modern option. The advantage is simplified welding, since there is no need to strip the ends of the reinforcing layer and calibrate. Since the frame is soldered into the body of the product, there is no such phenomenon as delamination. The linear expansion coefficient is 6%.
Aluminum reinforcement can be continuous, when during the production of pipes an aluminum strip is inserted into their body, or perforated. The second option is to replace the tape with a mesh with small holes.
PP pipe reinforced with strip aluminum foil tolerates high temperatures well. Actually this is already a full-fledged metal-plastic pipe. Such pipes are connected along the inner layer. Before this, the outer shell and the reinforcing layer are removed.
With characteristic differences between metal-plastic and polypropylene pipes read the article, dedicated to the analysis of the properties and assessment of the qualities of both varieties.
In cold regions, even the highest quality polypropylene pipes are not recommended for centralized hot water supply and heating. It is better not to expose plastic communications to significant temperature changes.
Fittings for water supply system made of PP pipes
The name “fitting” itself comes from the English “fit”, which in translation sounds like “to assemble”. With their help, pipes are joined in a straight line, at an angle, and form contours and branches. In this case, the pipeline can include both pipes of the same diameter and different ones.
Many enterprises produce polypropylene pipes; they are constantly expanding their range of products. It includes both simple and complex fittings for polypropylene pipes. These elements for connecting pipes are threaded, crimped, and welded.
The water supply system is created using the following types:
The first of them, with a barrel-shaped geometry, is the simplest. The internal diameter of the “barrel” is identical to the external diameter of the pipe. Its purpose is to connect pipes of equal cross-section.The water pipeline requires complete tightness; only welding can provide it.
To do this, the connecting elements must be made of the same material as the PPT. Since these parts are bell-shaped, they are put on the pipe. The connection occurs after heating the two parts. If unheated pipe can be inserted into the fitting, it is not suitable for piping installation.
Classification of fittings for PP pipelines
The material from which polypropylene fittings are made may have a different composition, which affects thermal stability.
Based on this feature, there are 3 types:
- homopropylene - abbreviated as PPG, marking - RRN, PP-1;
- block copolymer - denoted by the abbreviation PPV, markings - PPV, PP-S, PP-2;
- round copolymer - PPR, labeled - PP-3, PPRC, PPCR.
The first type is polypropylene with the inclusion of special modifying additives - nucleators, fire retardants, antiseptics. They impart a certain set of properties to the final product. Both pipes of this type and fittings are suitable exclusively for cold water supply.
The second is a polymer made up of homopolymer micromolecules arranged in a precise order. The finished product made from this material has high impact resistance. Since it can withstand high temperatures, it is suitable for hot water supply.
The structure of the rondom copolymer is crystalline.The product does not lose its properties over a wide temperature range - -170 - 1400⁰. Elements made of this material can have a cross-section from 1.6 to 11 cm. They are used in many engineering networks. The characteristics of polypropylene also include such a parameter as MRS. This is a characteristic of the shortest duration of strength.
It is related to the maximum permissible pressure in the line. This pressure is guaranteed to ensure the impeccable service of the pipeline when transporting water with a temperature of 20⁰ for 50 years. The indicator is directly related to the thickness of the pipe wall.
Pressure values are encoded in the abbreviation PN with a digital prefix. It indicates the maximum permissible pressure during operation. The higher the digital designation, the greater the pressure load the pipe can withstand.
Examples: PN10 - a pipe with a designated pressure of 10 bar, a pressure of 16 bar corresponds to a PN16 pipe.
You can select both connecting elements and pipes for assembly heating systems And polypropylene water pipe by purpose:
- for passing cold water;
- for transporting hot (maximum 70⁰) water.
There are also pipes used to create heating systems: low-temperature (maximum 60⁰) floor systems and radiator systems up to 90⁰.
Features of polypropylene couplings
PP couplings have thickened walls. The pipes are inserted into the coupling joint using some effort.
The main thing is that the part of the pipe that gets into the coupling is absolutely smooth.The pipe is inserted into the connecting element until it stops, after fitting it is removed and heated to welding ironso that it is strong and airtight connect the parts of the PP pipeline.
Transition elements for products of different diameters
Products of different sections are connected using a special type of adapters. It performs the same role as the coupling, but connects different diameters. If you need to continue the polypropylene pipe with a metal one, these connecting elements are also used.
In this case, they differ from simple couplings in the presence of an internal thread on one side. This adapter hermetically connects smooth sections of the water main.
Corners and their scope of application
Plumbing is not always a perfect straight line. Sometimes it becomes necessary to form a right angle. Polypropylene is a rigid material and inflexible in working condition. But it can be bent if only preheated. Another thing is that you don’t need to do this.
When the design temperatures and pressures increase slightly, a leak may occur. The best solution in this situation is to use a fitting bent at the appropriate angle.
The bending angle is 45, 90⁰. There are corners with carvings on one side. Yes, mounting bathroom faucet, use an angle having a cross-section of 2 cm on one side and a 3-quarter internal thread on the other.
Using tees and crosses
In situations where it is necessary to bring together more than two bends, tees and crosses are used. For example, it is necessary to supply water from the riser to the bathroom or to the kitchen sink.
Such fittings have many modifications. Some pipes run at a 90⁰ angle, others at an acute angle. For installation shut-off valves For connections of this kind, fittings are produced with threads on one side. The second side is for welding connections.
The temperature and heating time of polypropylene parts are strictly regulated. Will familiarize you with the indicated values next article, in which, in addition to these important parameters, you will find a detailed guide to connecting PP parts by soldering.
Bypass elements for water mains
In the case of laying a water pipeline passing along a complex trajectory, it is impossible to do without bypass curved parts. They are necessary when the pipe needs to be laid to bypass obstacles located near the wall. They change the direction of the highway smoothly.
Visually, these parts are similar to squares, but their bend is more round. With their help, it is possible to rotate the water supply by 120⁰.
They produce polypropylene bypass fittings from PPR brand PP.Such elements also fit well into corner joints, and this is important when communications are located externally.
Correct selection of fittings by diameter
The selection of plastic fittings, as well as the connection method, is carried out based on the material of the pipes. In any case, a diagram is first created, then the type of connecting elements is determined.
Fittings for diffuse welding or soldering are suitable for a system of polypropylene pipes. This is an inexpensive method, but provides a monolithic and 100% sealed connection of polypropylene pipesused in the assembly of heating systems, sewer and water supply networks of any complexity.
The diameters of the connecting elements are related to the diameter of the pipes. In turn, the latter value is interconnected with such a parameter as the throughput of the water supply system. When selecting the required diameter, you need to take into account several nuances.
The marking of pipe products includes the outer diameter, the value of which also takes into account the rather thick walls of the pipe. Therefore, with the same outer diameter, the permeability of a polypropylene pipe will be less than, for example, a metal-plastic one.
The polypropylene pipe inside is absolutely smooth, as opposed to steel. No deposits linger or accumulate in it. So if initially the internal diameter of this type of pipe was the same, the PP pipe will provide more efficient passage.
For water supply in a cottage or apartment with a standard set of water intake points, the best option would be a pipe with a diameter of 20 mm. Large diameters (50 mm) are more suitable for the implementation of water supply schemes for microdistricts.
Fittings are not needed in this case. Docking is done by welding. To include check valves and gate valves into the system, steel flanges are used.
Some additional tips for choosing
Selecting PP pipes and the same fittings for water supply is a crucial moment.
When going to the construction market, it does not hurt to remember that it is useful to be guided by the following key criteria:
- features of the future system in specific conditions;
- type of engineering communications.
Types of PP pipes used in the construction of heating systems, are given here. We recommend reading this very useful article.
Any pipeline has its own characteristics.
They should also be taken into account when choosing:
- For water supply pipes, gray or white polypropylene pipes are mainly used.
- Assembly of a polypropylene pipeline involves the use of specific soldering iron for PP pipes and special types of pipe cutters.
- If the choice is difficult due to the breadth of the assortment, you need to take products that combine such parameters as quality, cost, convenience, and inexpensive installation.
- You need to know that connecting elements for PP pipes cannot be replaced with fittings designed for PVC pipes, even if they have the same dimensions.
Each manufacturer positions its products with high quality and durability. Therefore, to make a decent choice, you need to compare pipes produced by different companies according to some parameters.
The first parameter is the presence of the required diameters, atypical connections, and weight. Appearance is also important. If this is a decisive moment, then pipes made in the Czech Republic look more presentable, while Turkish ones are inconspicuous in comparison. In particular, Czech FV PPR pipes are an excellent option for cold and hot water supply.
Faser produces fittings and accessories for them. FV THERM pipes are also suitable for supplying hot water, but due to the high cost this is not practical. The manufacturer Facer, in order to visually distinguish products for cold water supply, marks them with stripes on a white surface.
Another nuance is the SDR value. With a high rate, excellent cross-country ability is observed with relatively thin walls. Low SDR is a sign of low permeability with high density and strength at the same time. Durability and service life are also important. Manufacturers' warranties should not be ignored.
The scraps of polypropylene pipe remaining after the construction of the pipeline can always be used. For example, you can make a chair for a country or home environment. You will find instructions for making it in our recommended article.
Conclusions and useful video on the topic
Video #1. Principles for choosing PP pipes:
Video #2. Recommendations from plumbing equipment sellers on choosing PP pipes and components:
You will learn about all the technical characteristics of the products, as well as the company that produced them, from the markings located directly on the product. Don't forget to study them when purchasing. Don't neglect the advice of experts either.
With good initial preparation, you can independently design an excellent plumbing system for your home.If you have doubts about your abilities, it will be cheaper to turn to plumbers. Otherwise, rework may entail significant additional costs.
Tell us about how you bought polypropylene pipes and fittings for assembling home or country communications. Share the criteria that influenced your choice of products. Please leave comments, ask questions and post photos on the topic in the block below.
Polypropylene pipes and fittings