When laying pipeline structures, it is necessary to ensure their protection from external influences that can disrupt the operation of the pipes. PPM insulation is used to perform protective functions. Recently, pipelines using this technology have been so popular. In total, there are three types of layers in the insulating protection of metal structures, and PPM belongs to them.
What is PPM insulation
It is a material based on polyurethane components and mineral filler. When laying pipelines, metal products are often insulated to reduce heat loss. In their work, enterprises use the set of rules No. 124.13330.2012 based on the SNiP «Heat Networks», which specifies the requirements for laying underground channelless heating networks.
Characteristics and properties of the material according to GOST
The table shows the indicators:
|The value of the coefficient of thermal conductivity||0.044 W/(m-°C)|
|Bulk weight||250 ± 50 (insulating layer -100 kg/m3)|
|Heat resistance||150 degrees|
|Mandatory continuous remote monitoring of insulation dampening||Not required|
|maintainability||Can be repaired|
|Protection against mechanical damage||No need to install protection from external factors|
|The stability of the material, how quickly drying occurs after the appearance of moisture. Another name for the indicator is vapor permeability.||Drying is fast, insulation withstands moisture.|
|Flammability||The material is not dangerous, when you try to set it on fire, it fades on its own.|
|Toxicity||The layers use environmentally friendly materials.|
|Material to corrosion ratio||The starting medium has a neutral pH|
The production of PPM protective layer for equipment is being improved, which makes it possible to improve its performance. Due to the low vapor permeability, less dripping moisture penetrates into the insulation. Due to this, the quality characteristics of the material remain on top. There is no caking, no loss in the strength of the composition used.
Foam polymeric material belongs to the group of rigid polyurethane foams. This is a foamed raw material into which a mineral filler is introduced. Ash or sand is used as the latter. There is no chemical reaction between these components. After mixing the polymer and mineral filler, the end result is a simple mixture.
As a rule, the composition includes polymer components and a finely dispersed filler. It is this set that provides the final product to combine the properties of two materials into one:
- polyurethane foams;
- Polymer concrete.
This reduces the consumption of raw materials and the final cost of the final product. When mineral and other additives are included, highly filled systems are formed. The properties of the final product are significantly improved:
- Physical and chemical;
- Thermal physical;
PPM insulation, to improve certain characteristics, may contain a synthetic base and various mineral fillers, which leads to a change in product modification.
Benefits of using
When using it, certain advantages are noted when compared with other products that perform insulating functions on pipelines. The benefits largely depend on the properties of the material.
The positive aspects of using the pipeline insulation in question:
- Over time, there is no deterioration in the physical characteristics of the material. Also, there is no decrease in the thickness of the applied layer;
- A pipeline dressed in such clothing has a low absorption coefficient;
- Low thermal conductivity, due to which there is no large heat loss in the line. The conducted experiments show that, being in a shell of foam-polymer-mineral insulation, pipes lose no more than 4 percent of heat. If we draw parallels with other insulating materials, for example, mineral wool, then here the thermal conductivity is higher and heat losses are increased by 2-3 times;
- The price of this type of casing for highways is much lower than other conventional heat preservation technologies;
- the period of use of pipelines has been increased and is more than 30 years;
- pipelines with a polymer coating operate longer without repairs and accidents, which significantly reduces the cost of maintaining and maintaining pipelines;
- after the pipe breaks, there will be no deformation of the skin. The insulation will dry and continue to function;
- no sensors are installed on the pipelines, aimed at the operational control of the state of the insulation layer.
Mass use as a heat-insulating material is observed in the construction of heating mains. This happens on the basis of regulatory documentation, in which the specified insulation is part of the “representative designs of heat pipelines”. In particular, in the set of rules developed for channelless laying of heat supply networks, there is an exact indication of this technology.
Pipes do not always come with a protective layer applied, then it is made independently, by pouring directly at the installation site. The maximum heating temperature of the material is allowed, up to 150 degrees, at the specified temperature of the coolant.
If the pipeline runs on the surface of the earth, then it is necessary to install an additional layer on top that protects against ultraviolet rays. It can be either a separate layer or additives with special UV-absorbents.
The insulation is applied to the pipe from the outside. At the same time, the polymer-mineral shell consists of three layers:
- the first cover consists of a material that protects the line from corrosion. It is carried out with a thickness of up to 10 millimeters;
- this is followed by the main layer responsible for the preservation of heat;
- the last and extreme is a layer that protects the pipe from mechanical damage. The layer is denser than the underlying coatings. Here the thickness can reach 15 millimeters
Application is made on products with a diameter of 32-820 millimeters, up to 12 meters long. How the pipe will be produced does not matter. It can be seamless or welded. In the production of metal structures, GOST 8731, 10704, 8733, 20295 are used.
A layer with thermal insulation properties is applied not only to straight sections of the pipeline. To obtain a highly efficient main, which will deliver heat to houses with minimal losses, it is necessary to completely cover it. To do this, the layers are laid on the following connecting parts:
- adapters between pipes;
- taps required for branching to houses;
- tees, other fittings that can be used when laying a heating main.
For information on how to properly seal the seams at the joints of pipes, see the exact installation instructions for these products.
When the pipe is hidden in PPM insulation from external influences with a foam-polymer-mineral mass, its service life increases and reaches 30 years. There is no need to install state controllers. The pipe is reliably protected from corrosion and freezing. The protective layer also keeps the physical properties unchanged during the specified period.
The manufacturer gives a guarantee for the pipeline equal to 30 years.
Feature of operation
The use of metal products wrapped with PPM insulation allows layers to solve a lot of problems that invariably arise during construction and in the future use of networks. However, before installing the pipeline, you should know certain nuances that may arise during the operation period:
- reliable waterproofing function is present only on the top layer;
- the dielectric index of the metal can cause the loss of the protective layer due to its premature destruction. Therefore, before applying insulation, it is required to degrease the surface of the pipe, it is necessary to remove dissolved oxygen, hard salts, pollution;
- in places where the pipeline is located above the ground, it is necessary to check the condition more often. For this, a check order is established.
The check contains the following items:
- safety of the insulation layer;
- if the PPM insulation used for pipes is painted, then the integrity of the helmet coating;
- piping line is checked. Intermediate and manholes are inspected.