Thermal insulation for heating pipes outdoors

not so often in the practice of private construction, but still there are situations when the heating of communication is required not only to breed on the premises of the main house, but also to lend them to others, near the location of the building.It may be accommodation wings, outbuildings, summer kitchen, commercial or agricultural buildings, for example, use for the content of domestic animals and poultry.Do not be excluded that, when, on the contrary, itself an autonomous boiler room located in a separate building, some distance from the main residential building.It happens that the house is connected to the central heating pipes from which the pipes are drawn to it.

gasket between the buildings heating pipes can be two options - underground (channel or the Underground) and open.Less time consuming process is seen as a local installation of a heating above the ground, and to this option in a self-build resort more often.One of the main conditions for the effectiveness of the work - a properly planned and executed quality insulation for heating pipes in the open air.This question will be discussed in this publication.

What is the thermal insulation of pipes and basic requirements for her

it seems nonsense - why warm already almost always hot pipe heating system?Perhaps someone can enter a kind of "play on words" misleading.In this case, of course, correct to be a conversation, in terms of "insulation".

Thermal insulation works on all pipelines have two main objectives:

• If pipes are used in the heating or hot water supply systems, at the forefront reduction of heat loss, maintaining the desired temperature of the pumped liquid.The same principle holds for industrial or laboratory facilities where technology is required to maintain a certain temperature transmitted through pipes substance.
• For pipelines of cold water supply or sewer communications becomes the main factor is insulation, it eats to prevent the fall of temperature in the pipes below the critical level, to prevent freezing, leading to system breakdown and deformation of pipes.

way, such a precaution is required for heating pipes, and pipes for hot water - no one is completely safe from emergencies on boiler equipment.

very cylindrical shape of the pipe determines the very considerable area of ​​permanent heat exchange with the environment, so - significant heat loss.And, naturally, they grow with increasing pipe diameter.The table below illustrates how the value of heat, depending on the temperature difference between inside and outside of the tube (column Δt °), the diameter of the pipe and the thickness of the insulation layer (contains data based on the use of insulation material having an average coefficient of thermal conductivity λ = 0,04W / m × ° C).

thickness of the insulation layer.mm	Δt. ° C	External pipe diameter (mm)
15	20	25	32	40	50	65	80	100	150
magnitude of heat loss(1 meter pipeline. W).
10	20	7.2	8.4	10	12	13.4	16.2	19	23	29	41
30	10.7	12.6	15	18	20.2	24.4	29	34	43	61
40	14.3	16.8	20	24	26.8	32.5	38	45	57	81
60	21.5	25.2	30	36	40.2	48.7	58	68	86	122
20	20	4.6	5.3	6.1	7.2	7.9	9.4	11	13	16	22
30	6.8	7.9	9.1	10.8	11.9	14.2	16	19	24	33
40	9.1	10.6	12.2	14.4	15.8	18.8	22	25	32	44
60	13.6	15.7	18.2	21.6	23.9	28.2	33	38	48	67
30	20	3.6	4.1	4.7	5.5	6	7	8	9	11	16
30	5.4	6.1	7.1	8.2	9	10.6	12	14	17	24
40	7.3	8.31	9.5	10.9	12	14	16	19	23	31
60	10.9	12.4	14.2	16.4	18	21	24	28	34	47
40	20	3.1	3.5	4	4.6	4.9	5.8	7	8	9	12
30	4.7	5.3	6	6.8	7.4	8.6	10	11	14	19
40	6.2	7.1	7.9	9.1	10	11.5	13	15	18	25
60	9.4	10.6	12	13.7	14.9	17.3	20	22	27	37

as the insulation thickness increase the overall rate of heat loss is reduced.However, note that even a fairly thick layer of 40 mm does not exclude the heat completely.Only one conclusion - should strive to ensure that the use of insulation material with the lowest possible coefficient of thermal conductivity - it is one of the main requirements for the thermal insulation of pipelines.

Sometimes it is necessary and heating system pipes!

when laying water or sewage communication happens that due to the peculiarities of the local climate or the specific conditions of a thermal insulation assembly is not enough.One has to resort to forced to heating water pipe , to install heating cables - more this issue is considered in a special publication of our portal.

• The material used for insulation of pipes, where possible, should possess hydrophobic properties.Not only will current from a heater immersed in water - and it will not prevent heat loss, and he will soon be destroyed by the action of negative temperatures.
• thermal insulation design should have a reliable external protection.Firstly, it needs to be protected from atmospheric moisture, especially when applied to a heater capable of actively absorb water.Secondly, the material should close spectrum from ultraviolet sunlight acting on them fatal.Third, we should not forget about the wind load that could compromise the integrity of the thermal insulation.And fourth, there is a factor of the external mechanical impact, unintended, including from animal or due to trivial manifestations of vandalism.

In addition, for any owner of a private house, for sure, and indifferent moments aesthetics paved the heating duct.

• Any Applicability on heating mains insulating material must have a working temperature range corresponding to the actual application conditions.
• important requirement for insulation material and its outer wall - this is the longevity of use.No one will want to come back to the problems of thermal insulation of pipes, even once every few years.
• From a practical point of view, one of the main requirements of the thermal insulation acts simplicity of installation, and in any position and in any complex area.Fortunately, in this regard, the producers do not get tired to please the comfortable-to-use developments.
• important requirement for thermal insulation - its materials should themselves be chemically inert, and do not enter into any reaction with the pipe surface.Such compatibility - the key to long trouble-free operation.

The question of cost is also very important.But in this regard, the range of prices in specialized insulation for pipes - very big.

What materials are used for insulation of heating aerial

Choice insulating materials for the heating pipes at their outer lining - large enough.They are roll-type or in the form of mats, they can be given a convenient mounting or other curly cylindrical shape, have insulation, which are applied in liquid form and only acquire their properties after hardening.

Thermal insulation using polyethylene foam

foamed polyethylene rightly referred to as a very efficient thermal insulator.And what is very important, the cost of this material - one of the lowest.

Thermal conductivity of foamed polyethylene is usually in the region of 0.035 W / m × ° C - this is a very good indicator.Tiny isolated from each other bubbles filled with gas and create a flexible structure, and with such material if it purchased roll variation is very convenient to operate on difficult sections of pipe configuration.

This structure becomes a reliable barrier to moisture - with proper installation of any water or water vapor through it to get to the wall of the tube can not.

foam density is low (about 30 - 35 kg / m³), ​​and insulation in any way without weighing tube.

material with some assumptions can be classified as low-risk in terms of flammability - it usually refers to the class of G-2, that is, it is very difficult to ignite, but it quickly fades without an external flame.Moreover, the products of combustion, in contrast to many other thermal insulators, do not pose any serious toxic hazard to humans.

Round polyethylene foam for thermal insulation of external heating mains will be uncomfortable and unprofitable - it is necessary to wind the multiple layer, to achieve the desired thickness of insulation.It is much easier to use the material in the form of sleeves (cylinder), which includes an internal channel corresponding to the diameter of the insulated pipe.To fit over the pipe length of the cylinder is usually on the side of the incision is made, which after installation can be a reliable seal with tape.

more effective kind of foam - penofol, which on one side has a layer of foil.It becomes a kind of glossy finish termootrazhatelem that significantly increases thermal insulation qualities of the material.Also - this is an additional barrier against moisture.

Penofol can also be roll-type or in the form of cylindrical core elements - especially for thermal insulation of pipes for various purposes.

And polyethylene foam for thermal insulation of heating is used infrequently.Rather, it is suitable for other communications.The reason - a rather low temperature range of operation.So.if you look at the physical characteristics, the upper limit of the balances somewhere on the verge of 75 ÷ 85 ° C - above the possible disruption of the structure and appearance of deformities.For stand-alone heating, most often, a kind of temperature is sufficient, however, to the point, and for the central - thermal stability is clearly not enough.

Heat cladding elements made of polystyrene foam

All known polystyrene (in common parlance it is more commonly referred to as foam) is widely used for various types of thermal insulation works.Is no exception and insulation of pipes - for this special foam made parts.

Usually it is half-cylinders (for large diameter pipes can be segmented into one-third of the circumference at 120 °), which are to be assembled in a single structure equipped with a locking compound on the type of "thorn-groove".This configuration allows fully across the pipe surface to provide reliable thermal insulation, without remaining "cold bridges".

In everyday speech these items are called "shell" - for obvious similarity with it.Available are many types of it, under a different outer diameter insulated pipes and different thicknesses of insulation layer.Generally, the length of parts or 1000 to 2000 mm.

used to manufacture polystyrene PSB-S type of different brands - from PSB-S-15 PSB-S-35.The main parameters of this material are shown in the table below:

Ranked material parameters	Make Styrofoam
	PSB-S-15U	PSB-S-15	PSB-S-25	PSB-S-35	PSB-S-50
density (kg / m³)	10	15	15,1 ÷ 25	25,1 ÷ 35	35,1 ÷ 50
compressive strength at 10% deformation (MPa, no less)	0.05	0.06	0.08	0.16	0.2
bending strength (MPa, no less)	0.08	0.12	0.17	0.36	0.35
Thermal conductivity in dry state at a temperature of 25 ° C (W/ (m × ° K))	0,043	0,042	0,039	0,037	0,036
Water absorption for 24 hours (% by volume, not more)	3	2	2	2	2
Humidity (% max)	2.4	2.4	2.4	2.4	2.4

foam Advantages as insulation material known for a long time:

• It has a lowthermal conductivity.
• Lightweight material greatly simplifies the insulation works, which do not require any special tools or fixtures.