Pipeline insulation calculator in m³, how to calculate the volume correctly

Those who have once had to deal with freezing pipes know what a scourge this is. And for the rest of their lives they remembered an important rule - it is necessary to insulate the water supply systems in advance! Of course, it’s better to learn from other people’s mistakes.

That is why in our article we will consider such an issue as the correct calculation of thermal insulation of pipelines.

Work on the construction and insulation of the pipeline

Calculation methods

In order to decide on the choice of suitable insulation, it is necessary to calculate the optimal thickness and density of the material for a particular case. This calculation allows not only to reduce heat loss, but also to reduce the temperature of the pipes, for the purpose of their safe use.

What factors need to be taken into account when calculating?

• Temperature of the insulated surface;
• Temperature changes in the environment;
• The presence of mechanical influences (for example, vibration, etc.);
• Permissible loads on pipes;
• Loads from overlying soil and vehicles;
• The thermal conductivity coefficient of the selected insulation;
• Resistance of the insulating material to deformation.

Pipeline insulation with mineral wool

Important! SNiP 41-03-2003 clearly states what the characteristics of insulation materials should be for various types of pipelines and operating conditions. For example, for insulated pipes with temperatures below 12º C, according to SNiP requirements, the thermal insulation must include a vapor barrier layer.

Now we will look at the calculation of pipeline thermal insulation - two proven methods, each of which is convenient and reliable in its own way.

Engineering calculation using formulas

The optimal thickness of the insulation layer is found by technical and economic calculation: the thickness of the material is determined based on its temperature resistance - at least 0.86 (ºC m²/W) for pipes with a diameter less than or equal to 25 mm, and 1.22 (ºC m²/W ) for pipes with a diameter greater than 25 mm.

The information below will be useful when carrying out engineering calculations of thermal insulation for various pipelines. As an example, we will calculate the required insulation thickness for the exhaust manifold of a high-performance diesel engine.

The total temperature resistance of the insulating structure for a cylindrical pipe is determined by the following formula:

Formula for finding the temperature resistance of insulation

• diz – outer diameter of the insulation for the pipe;
• dн – outer diameter of the pipe;
• from is the thermal conductivity coefficient of the insulating material;
• c – heat transfer coefficient from the insulation to the air.

Linear heat flux density:

Finding the linear heat flux density

• tн – temperature of the outer wall of the pipe;
• tiz is the surface temperature of the insulating layer.

Temperature of the inner wall of the pipe insulation:

Finding the temperature of the inner wall of the pipeline insulation

• dв – internal diameter of the pipe;
• g – heat transfer coefficient from the gas to the wall;
• t is the thermal conductivity coefficient of the material from which the pipe is made.

Formula for finding heat balance:

Finding Thermal Balance

With its help, the required outer diameter of the insulation for the pipe (diz) is determined. Then the calculation of the thickness of the thermal insulation of pipelines is calculated using the formula:

Finding the thickness of insulation

Calculation example: the task was set to calculate the thermal insulation for a high-performance diesel pipeline.

The following values ​​are available:

• outer diameter of the pipeline – 0.6 m;
• its internal diameter is 0.594 m;
• temperature of the outer wall of the pipeline – 725 K;
• temperature of the outer surface of the insulation – 333 K;
• thermal conductivity coefficient of insulation is 0.11 W/(m K).

Substituting all the values ​​into the formulas given above, we obtain the required insulation thickness for the pipeline - at least 0.1 m.

Advice! If you think that you will not be able to use the above formulas correctly, then contact our engineers for help. They will make a professional calculation, which will allow you to be sure that the thermal insulation will be of really high quality. The price for specialist services is quite reasonable and accessible to everyone.

If you nevertheless decide to do all the work yourself, then remember that the calculation of the thickness of the insulation for the pipeline should be carried out under specific conditions - from the insulation material to seasonal temperature changes outside and air humidity. By the way, humidity significantly accelerates heat transfer and reduces the effectiveness of some insulation materials (for example, mineral wool).

Online calculator – an indispensable assistant in thermal insulation calculations

In addition to the services of a qualified engineer, there is the option of using an online assistant. The calculator for calculating thermal insulation of pipelines is an absolutely free program that does not require installation or any payment. With its help, you can do it yourself and make an accurate calculation in a matter of minutes.

This is what the online assistant actually looks like

Using the calculator is quite simple.

First, you are asked to choose one of four tasks:

• insulation of the pipeline in order to ensure the specified temperature on the insulation surface;
• insulation of the pipeline in order to prevent freezing of the liquid contained in it;
• insulation of the pipeline to prevent moisture condensation on the insulation surface;
• insulation of the pipeline of a water heating network of two-pipe underground channel laying.

Next, you will be asked to enter some data necessary for the calculation:

• insulation material (in the proposed list you will certainly find the insulation you prefer);
• outer diameter of the pipeline (mm);
• temperature of the insulated surface (ºC);
• how long does it take before water freezes in a state of inertia;
• the presence of a protective coating (metallic or non-metallic);
• average temperature of the coolant (water, etc.).

Enter all the necessary parameters

Now all that remains is to press the “calculate” button and get the most accurate result.

The result will appear in approximately this form:

Ease of use of the calculator

Regardless of the type of highways, they are all subject to insulation. Usually they try to lay pipes underground. But in private construction, it is not uncommon for some fragments of engineering systems to pass along the street, through a basement, attic or unheated room. External installation becomes a forced decision if, for example, it is necessary to install a water supply or heating main to an auxiliary or technical building, and the boiler room is located in a residential building.

Such a section of the highway must be protected differently than underground communications: from the physical effects of natural phenomena (freezing), corrosion, and also to minimize thermal energy losses. All these problems are solved with the help of additional thermal insulation. It is worth saying that calculating the volume of pipeline insulation on a calculator is convenient for three reasons:

• Optimizes costs.
• Saves your time.
• Offers additional features. For example, when calculating mineral wool cylinders, linear meters are converted to volume (m³). This allows you to understand which vehicle is suitable for transporting the material.

Thermal insulation is the path to savings Source jhmrad.com
Correct calculation will allow the work to be completed correctly, and the pipes will be maintained in proper condition. The choice of material also plays an important role, because it not only prevents heat loss, but also prevents corrosion, and, therefore, helps to extend the life of the system.

Choosing insulation

The main reason for pipeline freezing is insufficient energy circulation speed. In this case, at sub-zero air temperatures, the process of crystallization of the liquid may begin. So high-quality thermal insulation of pipes is vital.

Attention! This is especially true for those pipelines that operate intermittently (for example, a water heating system in a country house). Therefore, in order to avoid having to defrost and restore the system, you need to take care of its thermal insulation in advance.

Fortunately, our generation is incredibly lucky. In the recent past, insulation of pipelines was carried out using only one technology, since there was only one insulation - glass wool. Modern manufacturers of thermal insulation materials simply offer the widest selection of pipe insulation materials, differing in composition, characteristics and method of application.

It is not entirely correct to compare them with each other, much less to say that one of them is the best. So let's just look at the types of pipe insulation materials.

Examples of thermal insulating materials

The process of high-quality thermal insulation or heating insulation is carried out by many companies. Although this process is established at a high level in our time, the majority of people prefer to carry out thermal insulation on their own.

Foam insulation.

At the same time, polyethylene foam is resistant to high temperatures, is environmentally friendly and easy to install directly on the street. The main thing is, after the cover is put on, do not forget to glue its ends together.

Mineral wool. It can be of two types:

• basalt wool - operates at temperatures up to 650˚C and does not emit toxic substances. The material is made from rock with the maximum composition of basalt.
• fiberglass wool - made from quartz sand and glass. Works well at temperatures up to 180˚C.

The following types of thermal insulation are used in parallel with waterproofing:

• in the process of insulation with mineral wool, aluminum foil is wound over the base layer, which is secured with metal wire;
• For engineering structures, foam molds can be made, which allow you to insulate the pipeline yourself.

Due to the fact that polystyrene foam does not 100% repel water, it is not the best option for insulating outdoor heating.

Pipeline insulation options

Finally, we will consider three effective methods of thermal insulation of pipelines.

Perhaps one of them will appeal to you:

1. Insulation using a heating cable . In addition to traditional isolation methods, there is also an alternative method. Using the cable is very convenient and productive, considering that you only need to protect the pipeline from freezing for six months. In the case of heating pipes with cables, there is a significant saving of effort and money that would have to be spent on earthworks, insulation material and other issues. The operating instructions allow for the cable to be located both outside and inside the pipes.

Additional thermal insulation with heating cable

1. Air insulation . The mistake of modern thermal insulation systems is this: they often do not take into account the fact that soil freezing occurs according to the “top to bottom” principle. The freezing process is met by a flow of heat emanating from the depths of the earth. But since insulation is carried out on all sides of the pipeline, it turns out that I also insulate it from rising heat. Therefore, it is more rational to install insulation in the form of an umbrella over the pipes. In this case, the air gap will act as a kind of heat accumulator.
2. "Pipe in pipe" . Here, more pipes are laid in polypropylene pipes. What advantages does this method have? First of all, the advantage is that the pipeline can be heated in any case. In addition, heating is possible using a device for suctioning warm air. And in emergency situations, you can quickly extend the emergency hose, thereby preventing all negative aspects.

Insulation based on the “pipe-in-pipe” principle

Types of insulating material

Insulation materials by area of ​​application are:

1. insulation materials suitable for cold and hot water supply systems, for networks with central heating, for various types of technical equipment.

2.for sewerage pipes, also drainage pipes.

3.for ventilation equipment, freezing devices.

Insulation materials have different appearances, which determine the installation technology:

1.roll type.

2.foliage type.

3. casing type.

4.fill type.

5.combined type.

Attention! Insulating materials must have a low level of thermal conductivity and high resistance to ignition. These properties are endowed with:

These properties are endowed with:

1. insulation made of mineral wool, which is produced in rolls. Used for thermal insulation of pipelines containing coolant at high temperatures. Mineral wool is wound around the pipeline. Fastening with synthetic twine or stainless steel wire. Therefore, for large volume pipelines this material is considered not economical.

2. insulation made of polystyrene foam, otherwise shell. Convenient for installation work, resistant to fire, and has low thermal conductivity and moisture absorption. The material is indispensable when laying water pipes and heating systems. It is used at any temperature, for pipelines made of steel, metal-plastic or polymers. The material is produced in the form of cylinders; the internal size of the insulation can be selected for any pipeline.

3. foam insulation. The characteristics are not inferior to expanded polystyrene, but differ in the installation method. It is applied using a spray machine because the material is in a liquid state. When penoizol hardens, it forms a hermetic shell, which has a low level of thermal conductivity. The insulation does not require any fastening elements.

Attention! Penoizol insulation is an expensive insulation material. 4.polyethylene foam insulation

As a rule, they are used on water pipelines and are easy to install. The material is cut into strips of the required length, the pipes are wrapped, secured with tape. Some manufacturers produce insulation in the form of a cut pipe on one side, which must be put on the pipe

4. insulation made of foamed polyethylene. As a rule, they are used on water pipelines and are easy to install. The material is cut into strips of the required length, the pipes are wrapped, secured with tape. Some manufacturers produce insulation in the form of a cut pipe on one side, which must be put on the pipe.

5. insulation made of foil foam. Refers to modern types of insulation. The material includes polished aluminum foil and polyethylene foam. The insulation retains heat well. The foil is distinguished by its heat-reflecting qualities, therefore it accumulates and reflects heat back to the pipe.

When choosing a material, it is necessary to take into account the conditions of use, the properties of the insulation, the ease of installation, as well as the calculated thermal insulation values ​​in order to carry out insulation work at a high level.

Conclusion

So we discussed all the most important points regarding the insulation of pipelines. Regardless of what material and method you choose for this purpose, before you begin installing thermal insulation, it is advisable to calculate the amount of insulation required and its cost.

This way you will save effort and financial costs in the future. Good luck to all builders of your warm present and future! In the video presented in this article you will find additional information on this topic.

The thickness of the thermal insulation layer is calculated by the formula:

where: d is the outer diameter of the heat-insulated pipeline, mm;

B is the ratio of the outer diameter of the heat-insulating layer to the outer diameter of the pipeline, mm.

The value of B can be calculated from the following equation:

where: λk - thermal conductivity of the heat-insulating layer, W / (m × ºС) - taken according to the manufacturer's data; rtot - heat transfer resistance 1 l.m. thermal insulation structure / W, determined based on the normalized linear heat flux density according to the formula:

tw—average coolant temperature, ºС; tв — ambient temperature, ºС; qе - normalized linear heat flux density, W/m, taken according to Table 20; K1 is a coefficient that takes into account the change in the cost of heat and thermal insulation structure depending on the construction area and the method of laying the pipeline, adopted according to Table 18; re - thermal resistance of the pipeline wall, W / (m × ºС) - is not taken into account due to its small value for steel pipelines; αe is the heat transfer coefficient from the outer surface of the insulation, W / (m 2 × ºС), taken according to table 19.

Characteristics of network laying and standard calculation methods

Carrying out calculations to determine the thickness of the heat-insulating layer of cylindrical surfaces is a rather labor-intensive and complex process. If you are not ready to entrust it to specialists, you should be careful and patient to get the right result. The most common way to calculate the thermal insulation of pipes is based on standardized heat loss indicators. The fact is that SNiP establishes the values ​​of heat loss by pipelines of different diameters and with different methods of laying them:

Pipe insulation diagram.

• open method on the street;
• open in a room or tunnel;
• channelless method;
• in impassable channels.

The essence of the calculation is to select the heat-insulating material and its thickness in such a way that the amount of heat loss does not exceed the values ​​​​prescribed in SNiP. The calculation methodology is also regulated by regulatory documents, namely the relevant Code of Rules. The latter offers a slightly more simplified methodology than most existing technical reference books. Simplifications include the following points:

1. Heat losses when the pipe walls are heated by the medium transported in it are negligible compared to the losses that are lost in the layer of external insulation. For this reason, they can be ignored.
2. The vast majority of all process and network pipelines are made of steel; its heat transfer resistance is extremely low. Especially when compared with the same insulation indicator. Therefore, it is recommended not to take into account the heat transfer resistance of the metal pipe wall.

Methodology for calculating a single-layer thermal insulation structure

The basic formula for calculating the thermal insulation of pipelines shows the relationship between the amount of heat flow from an existing pipe covered with a layer of insulation and its thickness. The formula applies if the pipe diameter is less than 2 m:

Formula for calculating thermal insulation of pipes.

• λ — thermal conductivity coefficient of insulation, W/(m ⁰C);
• K is the dimensionless coefficient of additional heat loss through fasteners or supports, some values ​​of K can be taken from Table 1;
• tt is the temperature in degrees of the transported medium or coolant;
• to—outside air temperature, ⁰C;
• qL—heat flow value, W/m2;
• Rн - heat transfer resistance on the outer surface of the insulation, (m 2 ⁰C) / W.

The thermal conductivity value of the insulation λ is a reference value, depending on the selected thermal insulation material. It is recommended to take the temperature of the transported medium tt as the average throughout the year, and the temperature of the outside air tto as the average annual temperature. If the insulated pipeline runs indoors, then the ambient temperature is set by the technical specifications for the design, and in its absence it is taken equal to +20°C. The indicator of heat transfer resistance on the surface of a heat-insulating structure Rн for outdoor installation conditions can be taken from Table 2.

Note: the value of Rн at intermediate values ​​of coolant temperature is calculated by interpolation. If the temperature is below 100 ⁰C, the value of Rн is taken as for 100 ⁰C.

Indicator B should be calculated separately:

Table of heat losses for different pipe thicknesses and thermal insulation.

• diz - outer diameter of the heat-insulating structure, m;
• dtr — outer diameter of the protected pipe, m;
• δ—thickness of the thermal insulation structure, m.

Calculation of the thickness of pipeline insulation begins with determining the indicator ln B, substituting into the formula the values ​​​​of the outer diameters of the pipe and thermal insulation structure, as well as the thickness of the layer, after which the parameter ln B is found using the table of natural logarithms. It is substituted into the main formula along with the indicator of the normalized heat flow qL and make a calculation. That is, the thickness of the pipeline insulation must be such that the right and left sides of the equation become identical. This thickness value should be taken for further development.

The considered calculation method applied to pipelines with a diameter of less than 2 m. For pipes of larger diameter, the calculation of insulation is somewhat simpler and is carried out both for a flat surface and using a different formula:

• δ—thickness of the thermal insulation structure, m;
• qF is the value of the normalized heat flow, W/m2;
• other parameters are the same as in the calculation formula for a cylindrical surface.

Insulation materials

The range of means for installing insulation is very extensive.
Their difference lies both in the method of application on the surface and in the thickness of the thermal insulation layer. The application features of each type are taken into account by calculators for calculating pipeline insulation. The use of various bitumen-based materials with the use of additional reinforcing products, such as fiberglass or fiberglass, is still relevant. Polymer-bitumen compositions are more economical and durable. They allow for quick installation and the quality of the coating is durable and effective. The material, called polyurethane foam, is reliable and durable, which allows its use for both channel and non-channel methods of laying highways. Liquid polyurethane foam is also used, applied to the surface during installation, as well as other materials:

• polyethylene as a multilayer shell, applied in industrial production for waterproofing;
• glass wool of various thicknesses, an effective insulation due to its low cost with sufficient strength;
• For heating mains, mineral wool of the calculated thickness is effectively used to insulate pipes of various diameters.

Installation of insulation

Calculation of the amount of insulation largely depends on the method of its application. It depends on the place of application - for the internal or external insulating layer. You can do it yourself or use a calculator program to calculate the thermal insulation of pipelines. Coating on the outer surface is used for water pipelines for hot water supply at high temperatures to protect it from corrosion. Calculation with this method comes down to determining the area of ​​the outer surface of the water supply system to determine the need per linear meter of pipe.

Internal insulation is used for water main pipes. Its main purpose is to protect metal from corrosion. It is used in the form of special varnishes or a cement-sand composition with a layer several mm thick. The choice of material depends on the installation method - channel or non-channel. In the first case, concrete trays are placed at the bottom of an open trench for placement. The resulting gutters are closed with concrete lids, after which the channel is filled with previously excavated soil.

Ductless installation is used when digging a heating main is not possible. This requires special engineering equipment. Calculating the volume of thermal insulation of pipelines in online calculators is a fairly accurate tool that allows you to calculate the amount of materials without fiddling with complex formulas. Material consumption rates are given in the relevant SNiP.

Methodology for calculating a multilayer thermal insulation structure

Copper and steel pipe insulation chart.

Some transported media have a fairly high temperature, which is transferred to the outer surface of the metal pipe almost unchanged. When choosing a material for thermal insulation of such an object, they are faced with the following problem: not every material is able to withstand high temperatures, for example, 500-600⁰C. Products capable of contact with such a hot surface, in turn, do not have sufficiently high thermal insulation properties, and the thickness of the structure will be unacceptably large. The solution is to use two layers of different materials, each of which performs its own function: the first layer protects the hot surface from the second, which protects the pipeline from the effects of low outside air temperatures. The main condition for such thermal protection is that the temperature at the boundary of the layers t1,2 be acceptable for the material of the outer insulating coating.

According to section 4 SP 61.13330.2012

4.1 The thermal insulation structure must ensure the parameters of the coolant during operation, the standard level of heat losses by equipment and pipelines, and the temperature of their outer surfaces that is safe for humans.

4.2 Thermal insulation structures of pipelines and equipment must meet the requirements:

• energy efficiency - have an optimal ratio between the cost of the thermal insulation structure and the cost of heat losses through the insulation during the design service life;
• operational reliability and durability - withstand operational temperature, mechanical, chemical and other influences during the design service life without reducing heat-shielding properties and destruction;
• safety for the environment and operating personnel during operation and disposal.

Materials used in thermal insulation structures must not emit harmful, flammable, explosive, or unpleasant-smelling substances during operation, as well as pathogenic bacteria, viruses and fungi in quantities exceeding the maximum permissible concentrations established in sanitary standards.

4.3 When choosing materials and products included in thermal insulation structures for surfaces with positive coolant temperatures (20 °C and above), the following factors should be taken into account:

• location of the isolated object SP 131.13330;
• temperature of the insulated surface;
• ambient temperature;
• fire safety requirements;
• aggressiveness of the environment or substances contained in isolated objects;
• corrosive effects;
• surface material of the isolated object;
• permissible loads on the insulated surface;
• presence of vibration and shock impacts;
• the required durability of the thermal insulation structure;
• sanitary and hygienic requirements;
• temperature of application of thermal insulation material;
• thermal conductivity of thermal insulation material;
• temperature deformations of insulated surfaces;
• configuration and dimensions of the insulated surface;
• installation conditions (crowded conditions, altitude, seasonality, etc.);
• conditions for dismantling and disposal.
• The thermal insulation structure of underground ductless heating network pipelines must withstand without destruction:
• groundwater impact;
• loads from the mass of the overlying soil and passing vehicles.
• When choosing thermal insulation materials and structures for surfaces with a coolant temperature of 19 °C or lower and negative temperatures, the relative humidity of the surrounding air, as well as the humidity and vapor permeability of the thermal insulation material, should additionally be taken into account.

4.4 The required elements of the thermal insulation design for surfaces with positive temperatures must include:

• thermal insulation layer;
• cover layer;
• fastening elements.

4.5 The design of thermal insulation for surfaces with negative temperatures must include the following as mandatory elements:

• thermal insulation layer;
• vapor barrier layer;
• cover layer;
• fastening elements.

A vapor barrier layer should also be provided when the temperature of the insulated surface is below 12 °C. The installation of a vapor barrier layer at temperatures above 12 °C should be provided for equipment and pipelines with temperatures below ambient temperature, if the design temperature of the insulated surface is below the “dew point” temperature at the design pressure and humidity of the ambient air.

The need to install a vapor barrier layer in the thermal insulation structure for surfaces with variable temperature conditions (from “positive” to “negative” and vice versa) is determined by calculation to eliminate the accumulation of moisture in the thermal insulation structure.

Anti-corrosion coatings of the insulated surface are not included in the thermal insulation structures.

4.6 Depending on the design solutions used, the structure may additionally include:

• leveling layer;
• protective layer.

A protective layer should be provided when using a metal cover layer to prevent damage to vapor barrier materials.

Method for determining by a given value the reduction in coolant temperature

Materials for thermal insulation of pipes according to SNiP.

A problem of this kind is often posed when the transported medium must reach its final destination through pipelines at a certain temperature. Therefore, the determination of the insulation thickness is required to be made by a given temperature reduction value. For example, from point A the coolant leaves through a pipe with a temperature of 150⁰C, and to point B it must be delivered with a temperature of at least 100⁰C, the difference should not exceed 50⁰C. For this calculation, the length l of the pipeline in meters is entered into the formulas.

First, you should find the total heat transfer resistance Rп of the entire thermal insulation of the object. The parameter is calculated in two different ways depending on the following condition:

If the value (tt.start - tо) / (tt.fin - tо) is greater than or equal to the number 2, then the value of Rп is calculated using the formula:

In the given formulas:

• K is the dimensionless coefficient of additional heat loss through fasteners or supports (Table 1);
• tt.init - initial temperature in degrees of the transported medium or coolant;
• to—ambient temperature, ⁰C;
• tt.kon is the final temperature in degrees of the transported medium;
• Rп - total thermal resistance of insulation, (m 2 ⁰C) / W
• l is the length of the pipeline route, m;
• G—consumption of transported medium, kg/h;
• C is the specific heat capacity of this medium, kJ/(kg ⁰C).

Thermal insulation of steel pipe made of basalt fiber.

Otherwise, the expression (tt.start - to) / (tt.end - to) is less than the number 2, the value of Rp is calculated as follows:

The parameter designations are the same as in the previous formula. The found value of thermal resistance Rп is substituted into the equation:

• λ — thermal conductivity coefficient of insulation, W/(m ⁰C);
• Rн - heat transfer resistance on the outer surface of the insulation, (m 2 ⁰C) / W.

Then they find the numerical value of B and calculate the insulation using the familiar formula:

In this method for calculating pipeline insulation, the ambient temperature t should be taken based on the average temperature of the coldest five-day period. Parameters K and Rn - according to tables 1 and 2 above. More detailed tables for these values ​​are available in the regulatory documentation (SNiP 41-03-2003, Code of Rules 41-103-2000).

Briefly about the main thing

An online pipeline insulation calculator allows you to quickly calculate the thickness and volume of heat-insulating material. Thanks to the use of technology, you will save time, optimize costs and protect yourself from errors that are common in manual calculations with their cumbersome formulas.

Calculations may differ slightly depending on the task being set. For example, protection against heat loss, condensation or freezing of pipe contents. Accordingly, the data required to enter may vary.

Method for determining the surface temperature of an insulating layer based on a given temperature

This requirement is relevant in industrial enterprises where various pipelines run inside rooms and workshops where people work. In this case, the temperature of any heated surface is normalized in accordance with labor protection rules in order to avoid burns. Calculation of the thickness of the thermal insulation structure for pipes with a diameter over 2 m is carried out in accordance with the formula:

Formula for determining the thickness of thermal insulation.

• ɑ — heat transfer coefficient, taken from reference tables, W/(m 2 ⁰C);
• tп – normalized temperature of the surface of the heat-insulating layer, ⁰C;
• other parameters are as in the previous formulas.

The thickness of the insulation on a cylindrical surface is calculated using the equation:

Designations of all parameters are as in the previous formulas. According to the algorithm, this calculation is similar to calculating the thickness of insulation based on a given heat flow. Therefore, it is then carried out in exactly the same way; the final value of the thickness of the heat-insulating layer δ is found as follows:

The proposed method has some error, although it is quite acceptable for preliminary determination of the parameters of the insulating layer. A more accurate calculation is performed by the method of successive approximations using a personal computer and specialized software.