"Warm floors" are no longer perceived as a kind of exotic - more and more homeowners are turning to this technology for heating their residential properties. Such a system can fully take on the function of a full-fledged home heating, or work in tandem with classic heating devices - or convectors. Naturally, these features are taken into account in advance, at the stage of general design.
There are more than enough proposals for project development, installation and debugging of systems. And yet, many homeowners, according to the good old tradition, strive to do everything with their own hands. But such work "by eye" is still not done - one way or another, calculations are required. And one of key parameters is the total allowable length of pipes of one circuit.
And since, in the conditions of an ordinary average private residential building, as a rule, a pipe with a diameter of 16 mm is quite enough for laying, we will focus on it. So, we consider the question, what can be maximum length contour of a heat-insulated floor 16 pipe.
Why is it better to use a pipe with an outer diameter of 16 mm?
To begin with, why is a 16 mm pipe being considered?
Everything is very simple - practice shows that for "warm floors" in a house or apartment of this diameter is enough. That is, it is difficult to imagine a situation where the circuit does not cope with its task. This means that there is no really justified reason to use a larger, 20-millimeter one.
And, at the same time, the use of a 16 mm pipe provides a number of advantages:
- First of all, it is about a quarter cheaper than the 20mm counterpart. The same applies to all necessary fittings- the same fittings.
- Such pipes are easier to lay, with them it is possible, if necessary, to perform a compact step of laying out the contour, up to 100 mm. With a 20mm tube, there is a lot more fuss, and a small step is simply impossible.
- The volume of coolant in the circuit is significantly reduced. A simple calculation shows that in a linear meter of a 16 mm pipe (with a wall thickness of 2 mm, the inner channel is 12 mm) holds 113 ml of water. And in 20 mm ( inner diameter 16 mm) - 201 ml. That is, the difference is more than 80 ml per just one meter of pipe. And on the scale of the heating system of the whole house - this literally translates into a very decent amount! And after all, it is necessary to ensure the heating of this volume, which entails, in principle, unjustified energy costs.
- Finally, a pipe with a larger diameter will also require an increase in thickness. concrete screed. Like it or not, but at least 30 mm above the surface of any pipe will have to be provided. Let these "unfortunate" 4–5 mm do not seem ridiculous. Anyone who was involved in pouring the screed knows that these millimeters turn into tens and hundreds of kilograms of additional concrete mortar- It all depends on the area. Moreover, for a 20 mm pipe, it is recommended to make the screed layer even thicker - about 70 mm above the contour, that is, it turns out to be almost twice as thick.
In addition, in residential premises very often there is a “struggle” for every millimeter of floor height - simply for reasons of insufficient “space” to increase the thickness of the overall “pie” of the heating system.
A 20 mm pipe is justified when it is necessary to carry out a floor heating system in rooms with a high load, with a high intensity of people's traffic, in gyms, etc. There, simply for reasons of increasing the strength of the base, it is necessary to use more massive thick screeds, for the heating of which a large heat exchange area is also required, which is exactly what a pipe of 20, and sometimes even 25 mm, provides. In residential areas, there is no need to resort to such extremes.
It may be objected that in order to "push" the coolant through a thinner pipe, it will be necessary to increase the power indicators of the circulation pump. Theoretically, the way it is - the hydraulic resistance with a decrease in diameter, of course, increases. But as practice shows, most circulation pumps are quite up to the task. Below, attention will be paid to this parameter - it is also linked to the length of the contour. This is what calculations are made in order to achieve optimal, or at least acceptable, fully functional performance of the system.
So, let's focus on the pipe exactly 16 mm. We will not talk about the pipes themselves in this publication - that is a separate article of our portal.
What pipes are optimal for a water "warm floor"?
Not all products are suitable for creating a floor heating system. Pipes are embedded in the screed for many years, that is, their quality and performance characteristics there are special requirements. How to choose - read in a special publication of our portal.
How to determine the length of the contour?
The question seems to be quite simple. The fact is that on the Internet you can find a lot of recommendations on this matter - both from pipe manufacturers and from experienced craftsmen, and from, let's be honest, absolute amateurs who simply "rip" information from other resources, without particularly going into subtleties.
So, in the installation instructions that manufacturers often accompany their products, you can find the established limit for the length of the circuit for a 16 mm pipe reaches 100 meters. Other publications show a border of 80 meters. Experienced installers recommend limiting the length to 60 ÷ 70 meters.
It would seem, what else is needed?
But the fact is that the contour length indicator, especially with a vague definition of “maximum length”, is very difficult to consider in isolation from other system parameters. Lay out the contour "by eye", just so as not to exceed the recommended limits - an amateurish approach. And with such an attitude, it is quite possible to soon encounter deep disappointments in the operation of the system. Therefore, it is better to operate not with an abstract “permissible” contour length, but with an optimal one corresponding to specific conditions.
And it depends (more precisely, it does not depend as much as it is closely interconnected) on a host of other parameters of the system. This includes the area of the room, its purpose, the estimated level of its heat loss, the expected temperature in the room - all this will allow you to determine the step of laying the circuit. And only then it will be possible to judge its resulting length.
So we will try to “unravel this tangle” in order to come to the optimal length of the contour. And then - check the correctness of our calculations.
A few basic requirements for the parameters of the "warm floor"
Before proceeding with the calculations, it is necessary to familiarize yourself with some of the requirements that a water floor heating system must meet.
- "Warm floor" can act as the main heating system, that is, fully provide a comfortable microclimate in the premises of the house and compensate for heat losses. Another option, more rational - it acts as an "assistant" to ordinary radiators or convectors, taking on a certain share in common work systems, increasing the overall comfort in the home. In this case, the calculation should be carried out in close relationship - the owners must decide in advance in what proportion the overall system will work. For example, 60% is taken over by the high-temperature radiator system, and the rest is given to the "warm floor" circuits. It can also be used autonomously, for example, maintaining comfort in the premises during the off-season, when it still (or already) does not make sense to “drive the entire heating system to full”.
- The temperature of the coolant at the supply to the "warm floor" is limited - a maximum of 55 degrees. The temperature difference at the inlet and return must be in the range from 5 to 15 degrees. A drop of 10 degrees is considered normal (optimally, it is desirable to bring it up to 5 - 7).
The following modes of operation are usually taken into account.
Table of modes of operation of the water "warm floor"
- There are quite severe restrictions on maximum temperature warm floor surfaces. Overheating of floors is not allowed for a number of reasons. This is an uncomfortable feeling for a person’s legs, and difficulties in creating an optimal microclimate, and possible damage to the finish.
The following limit values surface heating for various rooms:
- Before starting the calculations, it is advisable to immediately draw up an approximate diagram of the layout of the circuit in the room. There are two main pipe laying patterns - "snake" and "snail" with multiple variations.
A - the usual "snake";
B - double "snake";
B - angular "snake";
G - "snail".
The usual "snake" seems to be laid out easier, but it turns out too many 180-degree turns, which increases the hydraulic resistance of the circuit. In addition, with this layout, a temperature difference can be clearly felt from the beginning of the circuit to the end - this is well shown in the diagram by a color change. The disadvantage can be eliminated by laying a double snake, but such installation is already more difficult to perform.
In the "snail" heat is distributed more evenly. In addition, 90-degree turns predominate, which reduces head losses. But laying such a scheme is still more difficult, especially if there is no experience in such work.
The circuit itself may not occupy the entire area of \u200b\u200bthe room - often pipes are not laid in those places where it is planned to install stationary furniture.
However, many masters criticize this approach. Stationarity of furniture - the value is still quite arbitrary, and the "warm floor" is laid for decades. In addition, the alternation of cold and heated zones is an undesirable phenomenon, at least from the point of view of possible appearance over time pockets of dampness. Unlike electrical systems, water floors are not threatened by local overheating due to closed areas, so there should be no concerns from this side.
So there is no strict framework in this regard. It is possible, in order to save material, to leave unfilled areas, or to lay the contour completely over the entire area. But if at some site it is planned to install furniture or plumbing devices that require fastening to the floor (for example, fastening the toilet with dowels or anchors), then this place, of course, remains free from the contour. There is simply a high probability of damaging the pipe when installing fasteners.
Which contour laying scheme is better to choose?
More details about the choice of laying schemes, with theoretical justifications, are described in a separate article on our portal.
- The pipe laying step can be from 100 to 300 mm (usually it is a multiple of 50 mm, but this is not a dogma). Less than 100 mm is neither possible nor necessary. And with a step of more than 300 mm, the “zebra effect” can be felt, that is, the alternation of warm and cold stripes.
But which step will be optimal - the calculations will show, since it is closely related to the expected heat transfer of the floor and the temperature regime of the system.
- One more caveat - all subsequent thermotechnical calculations shown for optimal pie sizes for underfloor heating systems.
It was said above that the thickness of the screed should be at least 300 mm above the surface of the pipes. But to ensure full accumulation and uniform distribution of heat, it is recommended to adhere to a thickness of 45-50 mm (namely for a pipe with a diameter of 16 mm).
Learn how to do it right, choose mixtures, prepare a solution, and also get acquainted with the technology of pouring water and electric underfloor heating.
And so that the generated heat is not wasted on heating interfloor overlap or other base of the "warm floor", a thermal insulation layer is necessarily provided under the pipe circuit. Usually, expanded polystyrene with a density of about 35 kg / m³ is used for this (extruded is better, as it is more durable and efficient). Minimum Thickness, ensuring the correct operation of the "warm floor" should be:
| Features of the base of the "warm floor" | The minimum thickness of the thermal insulation "cushion" |
|---|---|
| Floor over the ceiling above the heated room, the temperature in which is ˃ 18 °C | 30 mm |
| 50 mm | |
| Floor over the ceiling above the heated room, the temperature in which is from 10 to 17 °C | 70 mm |
| Floor on the ground, including in basements or basements with a depth from ground level up to 1500 mm. | 120 mm |
| Floor in basements or basements with a depth from ground level of more than 1500 mm | 100 mm |
Required condition- the floor heating system must be laid on a carefully insulated base, otherwise the heat will be spent extremely inefficiently All these last remarks have been made because the following calculations will be valid precisely for such recommended "ideal" conditions.
Carrying out calculations of the main parameters of the circuit
In order to lay the pipe contour with the optimal pitch (and its total length will subsequently depend on this), it is first necessary to find out what heat transfer is expected from the system. This is best shown by the specific heat flux density g, calculated per unit floor area (W/m²). Let's start with this.
Calculation of the specific density of the heat flux of the "warm floor"
Calculating this value, in principle, is not difficult - you just need to divide the required amount of thermal energy needed to replenish the heat loss of the room by the area of \u200b\u200bthe "warm floor". This does not mean the entire area of \u200b\u200bthe room, namely the “active”, that is, involved in the heating system, on which the circuit will be laid out.
Of course, if the "warm floor" will work in conjunction with conventional system heating, this is also immediately taken into account - only the planned percentage of the total heat output is taken. For example, 1.5 kW is required to heat a room (replenish heat loss), and the share of "warm floor" is assumed to be 60%. So, when calculating specific gravity heat flow we operate with a value of 1.5 kW × 0.6 = 0.9 kW
Where can we get the indicator of the total required power to compensate for heat losses? There are many recommendations based on the ratio of 1 kW of energy per 10 m² of floor space. However, this approach turns out to be too approximate, not taking into account a lot of important external factors and features of the room. Therefore, it is better to carry out a more thorough calculation. Don't worry - with our calculator it won't be too difficult.
Calculator for calculating the specific heat flux of "warm floor"
One of the conditions for the implementation of high-quality and proper heating premises with the help of a warm floor is to maintain the temperature of the coolant in accordance with the specified parameters.
These parameters are determined by the project, taking into account required amount heat for the heated room and flooring.
Required data for calculation
The efficiency of the heating system depends on a properly laid circuit.
To maintain the set temperature in the room, it is necessary to correctly calculate the length of the loops used to circulate the coolant.
First, you need to collect the initial data on the basis of which the calculation will be performed and which consist of the following indicators and characteristics:
- the temperature that should be above the floor covering;
- layout diagram of loops with coolant;
- distance between pipes;
- the maximum possible length of the pipe;
- the possibility of using several contours of different lengths;
- connection of several loops to one collector and to one pump and their possible number with such a connection.
Based on the above data, it is possible to perform the correct calculation of the length of the underfloor heating circuit and, due to this, to ensure a comfortable temperature regime in the room with minimal cost to pay for energy supplies.
Floor temperature
The temperature on the surface of the floor, made with a water heating device underneath, depends on functional purpose premises. Its values should not exceed those specified in the table:
Compliance with the temperature regime in accordance with the above values will create a favorable environment for the work and rest of the people in them.
Pipe laying options used for underfloor heating
Underfloor heating options
The laying scheme can be performed with a regular, double and corner snake or snail. Various combinations of these options are also possible, for example, along the edge of the room you can lay out a pipe with a snake, and then the middle part with a snail.
IN large rooms complex configuration, it is better to lay with a snail. In rooms of small size and with a variety of complex configurations apply serpentine styling.
Distance between pipes
The pipe laying step is determined by calculation and usually corresponds to 15, 20 and 25 cm, but no more. When laying out the pipes with a step of more than 25 cm, the human foot will feel the temperature difference between and directly above them.
At the edges of the room, the heating circuit pipe is laid in increments of 10 cm.
Permissible contour length
The length of the circuit must be selected according to the diameter of the pipe
It depends on the pressure in a particular closed loop and hydraulic resistance, the values of which determine the diameter of the pipes and the volume of fluid that is fed into them per unit time.
When installing a warm floor, situations often occur when the circulation of the coolant in a separate loop is disturbed, which cannot be restored by any pump, the water is locked in this circuit, as a result of which it cools down. This results in pressure losses of up to 0.2 bar.
Based practical experience, you can adhere to the following recommended sizes:
- Less than 100 m can be a loop made of metal plastic pipe 16 mm in diameter. For reliability optimal size is 80 m.
- Not more than 120 m take the maximum length of the circuit of 18 mm pipes made of cross-linked polyethylene. Experts are trying to install a circuit with a length of 80-100 m.
- No more than 120-125 m, the size of the loop for metal-plastic with a diameter of 20 mm is considered acceptable. In practice, they also try to reduce this length to ensure sufficient reliability of the system.
For a more accurate determination of the size of the loop length for the underfloor heating in the room in question, in which there will be no problems with the circulation of the coolant, it is necessary to perform calculations.
Application of several contours of different lengths
The device of the floor heating system provides for the implementation of several circuits. Of course, the ideal option is when all the loops have the same length. In this case, no adjustment and balancing of the system is required, but it is almost impossible to implement such a piping scheme. Detailed video about calculating the length of the water circuit, see this video:
For example, it is necessary to implement a floor heating system in several rooms, one of which, for example, a bathroom, has an area of 4 m2. This means that 40 m of pipe will be needed to heat it. It is not advisable to arrange contours of 40 m in other rooms, while loops of 80-100 m can be made.
The difference in pipe lengths is determined by calculation. If it is impossible to perform calculations, a requirement can be applied that allows a difference in the length of the contours of the order of 30-40%.
Also, the difference in the lengths of the loops can be compensated by increasing or decreasing the diameter of the pipe and changing the pitch of its laying.
Ability to connect to one node and pump
The number of loops that can be connected to one collector and one pump is determined depending on the power of the equipment used, the number of thermal circuits, the diameter and material of the pipes used, the area of heated premises, the material of the enclosing structures, and many other various indicators.
Such calculations must be entrusted to specialists with knowledge and practical skills in the implementation of such projects.
Loop size determination
The size of the loop depends on the total area of \u200b\u200bthe room
Having collected all the initial data, having considered the possible options for creating a heated floor and determining the most optimal of them, you can proceed directly to calculating the length of the water floor heating circuit.
To do this, it is necessary to divide the area of \u200b\u200bthe room in which the loops for water floor heating are laid by the distance between the pipes and multiply by a factor of 1.1, which takes into account 10% for turns and bends.
To the result you need to add the length of the pipeline, which will need to be laid from the collector to warm floor and back. The answer to the key questions of organizing a warm floor, see this video:
You can determine the length of the loop laid in 20 cm increments in a room of 10 m2, located at a distance of 3 m from the collector, by doing the following:
10/0.2*1.1+(3*2)=61 m.
In this room, it is necessary to lay 61 m of pipe forming a heating circuit in order to ensure the possibility of high-quality heating of the floor covering.
The presented calculation helps to create conditions for maintaining comfortable temperature air in small separate rooms.
To correctly determine the pipe length of several thermal circuits for a large number premises powered from one collector, it is necessary to involve the design organization.
She will do this with the help of specialized programs that take into account many different factors on which the uninterrupted circulation of water depends, and hence the high-quality floor heating.
Topics covered here include: the maximum length of the water floor heating circuit, the location of the pipes, optimal calculations, as well as the number of circuits with one pump and whether two are the same.
Seven times to measure calls for folk wisdom. And you can't argue with that.
In practice, to embody what has repeatedly scrolled in the head is not easy.
In this article we will talk about the work related to the communications of a warm water floor, in particular, we will pay attention to the length of its contour.
If we plan to install a water heated floor, the length of the circuit is one of the first issues that needs to be dealt with.
Pipe arrangement
The underfloor heating system includes a considerable list of elements. We are interested in tubes. It is their length that determines the concept of "the maximum length of a warm water floor." It is necessary to lay them taking into account the characteristics of the room.
Based on this, we get four options, known as:
- snake;
- double snake;
- corner snake;
- snail.
If done correct styling, then each of the listed types will be effective for space heating. Different can be (and most likely will be) the footage of the pipe and the volume of water. The maximum length of the water-heated floor circuit for a particular room will depend on this.
Main calculations: water volume and pipeline length
There are no tricks here, on the contrary - everything is very simple. For example, we chose the snake option. We will use a number of indicators, among which is the length of the contour of a water-heated floor. Another parameter is the diameter. Mostly pipes with a diameter of 2 cm are used.
We also take into account the distance from the pipes to the wall. Here it is recommended to fit in the range of 20-30 cm, but it is better to place the pipes clearly at a distance of 20 cm.
The distance between the pipes themselves is 30 cm. The width of the pipe itself is 3 cm. In practice, we get a distance between them of 27 cm.
Now let's move on to the area of the room.
This indicator will be decisive for such a parameter of a warm water floor as the length of the circuit:
- Let's say our room is 5 meters long and 4 meters wide.
- The laying of the pipeline of our system always starts from the smaller side, that is, from the width.
- To create the basis of the pipeline, we take 15 pipes.
- A gap of 10 cm remains near the walls, which then increases on each side by 5 cm.
- The section between the pipeline and the collector is 40 cm. This distance exceeds the 20 cm from the wall that we talked about above, since a water drainage channel will have to be installed in this section.
Our indicators now make it possible to calculate the length of the pipeline: 15x3.4 \u003d 51 m. The entire circuit will take 56 m, since we should also take into account the length of the so-called. collector section, which is 5 m.
The length of the pipes of the entire system must fit into the allowable range - 40-100 m.
Quantity
One of the following questions: what is the maximum length of a water floor heating circuit? What to do if the room requires, for example, 130, or 140-150 m of pipe? The way out is very simple: it will be necessary to make more than one contour.
In the operation of a water-heated floor system, the main thing is efficiency. If, according to calculations, we need 160 m of pipe, then we make two circuits of 80 m each. After all optimal length the contour of a water heated floor should not exceed this indicator. This is due to the ability of the equipment to create the necessary pressure and circulation in the system.
It is not necessary to make the two pipelines absolutely equal, but it is also not desirable that the difference be noticeable. Experts believe that the difference may well reach 15 m.
Maximum length of the water floor heating circuit
To determine this parameter, we must consider:
The listed parameters are determined, first of all, by the diameter of the pipes used for the warm water floor, the volume of the coolant (per unit of time).
In the installation of a warm floor, there is a concept - the effect of the so-called. locked loop. This is a situation where circulation through the loop will not be possible, regardless of the pump power. This effect is inherent in the situation of a pressure loss of 0.2 bar (20 kPa).
In order not to confuse you with long calculations, we will write a few recommendations that have been proven by practice:
- The maximum contour of 100 m is used for pipes with a diameter of 16 mm made of metal-plastic or polyethylene. Perfect option– 80 m
- A contour of 120 m is the limit for a 18 mm pipe made of cross-linked polyethylene. However, it is better to limit yourself to a range of 80-100 m
- With 20 mm plastic pipe, you can make a circuit of 120-125 m
Thus, the maximum length of a pipe for a warm water floor depends on a number of parameters, the main of which is the diameter and material of the pipe.
Are two identical ones necessary and possible?
Naturally, the situation will look ideal when the loops have the same length. In this case, you will not need any settings, the search for balance. But this is mostly in theory. If you look at practice, it turns out that it is not even advisable to achieve such a balance in a warm water floor.
The fact is that it is often necessary to lay a warm floor at an object consisting of several rooms. One of them is emphasized small, for example - a bathroom. Its area is 4-5 m2. In this case, a reasonable question arises - is it worth adjusting the entire area for a bathroom, splitting it into tiny sections?
Since this is not advisable, we come to a different question: how not to lose on pressure. And for this, elements such as balancing fittings have been created, the use of which consists in equalizing pressure losses along the contours.
Again, calculations can be used. But they are complex. From the practice of carrying out work on the installation of a warm water floor, we can safely say that the spread in the size of the contours is possible within 30-40%. In this case, we have every chance to get the maximum effect from the operation of a warm water floor.
Despite the considerable amount of materials on how to make a water floor on your own, it is better to turn to specialists. Only craftsmen can evaluate the working area and, if necessary, “manipulate” the pipe diameter, “cut” the area and combine the laying step when we are talking about large areas.
Quantity with one pump
Another frequently asked question: how many circuits can operate on one mixing unit and one pump?
The question really needs to be clarified. For example, to the level - how many loops can be connected to the collector? In this case, we take into account the diameter of the collector, the volume of coolant passing through the node per unit of time (the calculation is in m3 per hour).
We need to look at the data sheet of the node, where the maximum throughput factor is indicated. If we carry out calculations, then we will get the maximum indicator, but we cannot count on it.
One way or another, the device indicates maximum amount connection of circuits - as a rule, 12. Although, according to calculations, we can get both 15 and 17.
The maximum number of outlets in the collector does not exceed 12. Although there are exceptions.
We saw that installing a warm water floor is a very troublesome business. Especially in that part of it, where we are talking about the length of the contour. Therefore, it is better to turn to specialists so as not to redo later a not entirely successful styling that will not bring the efficiency that you expected.
The main argument in favor of the "warm floor" system is the increased comfort of a person's stay in the room, when, as heater the entire surface of the floor protrudes. The air in the room warms up from the bottom up, while at the floor surface it is somewhat warmer than at a height of 2-2.5 m.
In some cases (for example, when heating shopping malls, swimming pools, sports halls, hospitals), underfloor heating is the most preferred.
To the disadvantages of systems floor heating are relatively high, in comparison with radiators, the cost of equipment, as well as increased requirements for the technical literacy of installers and the quality of their work. Using quality materials and compliance with the installation technology of a well-designed water floor heating system, there are no problems during its subsequent operation.
The heating copper works on radiators in the mode 80/60 °C. How to connect the "warm floor"?
To obtain the design temperature (as a rule, not higher than 55 ° C) and the specified coolant flow rate in the circuit " warm floors"pump-mixing units are used. They form a separate low-temperature circulation circuit, into which the hot coolant from the primary circuit is mixed. The amount of mixed coolant can be set either manually (if the temperature and flow in the primary circuit are constant), or automatically using temperature controllers. Fully implement all the advantages of the "warm floor" allow pumping and mixing units with weather compensation, in which the temperature of the coolant supplied to the low-temperature circuit is adjusted depending on the outside temperature.
Is it allowed to connect a "warm floor" to the central heating or hot water system of an apartment building?
It depends on local legislation. For example, in Moscow, the installation of underfloor heating from common house water supply and heating systems is excluded from the list of permitted types of re-equipment (Decree of the Government of Moscow No. 73-PP of February 8, 2005). In a number of regions, interdepartmental commissions decisive question approvals for the installation of the "warm floor" system, require additional expertise and calculated confirmation that the "warm floor" device will not lead to disruption in the operation of common house engineering systems(see "Rules and regulations technical operation housing stock", clause 1.7.2).
From a technical point of view, connecting a "warm floor" to a central heating system is possible provided that a separate pumping station is installed. mixing unit with limited pressure return to house system coolant. In addition, if there is an individual heating point equipped with an elevator (jet pump), the use of plastic and metal-plastic pipes in heating systems is not allowed.
What material is better to use as a floor covering in the "warm floor" system? Can parquet floors be used?
Best of all, the effect of "warm floor" is felt when floor coverings from materials with a high coefficient of thermal conductivity (ceramic tiles, concrete, self-leveling floors, baseless linoleum, laminate, etc.). If carpet is used, it must have a "suitability mark" for use on a warm base. Other synthetic coatings(linoleum, relin, laminated boards, plastic compound, PVC tiles, etc.) must have a “no sign” of toxic emissions at elevated base temperatures.
Parquet, parquet boards and boards can also be used as floor heating, but the surface temperature should not exceed 26 °C. In addition, a safety thermostat must be included in the mixing unit. The moisture content of natural wood flooring materials should not exceed 9%. Works on laying parquet or plank flooring may only be carried out at a room temperature of at least 18 ° C and 40-50% humidity.
What should be the temperature on the surface of the "warm floor"?
The requirements of SNiP 41-01-2003 "Heating, ventilation and air conditioning" (clause 6.5.12) regarding the surface temperature of the "warm floor" are given in the table. It should be noted that foreign regulations allow several big values surface temperatures. This must be taken into account when using calculation programs developed on their basis.
How long can the pipes of the "warm floor" circuit be?
The length of one loop of the "warm floor" is dictated by the power of the pump. When it comes to polyethylene and metal-plastic pipes, then it is economically feasible that the length of a pipe loop with an outer diameter of 16 mm does not exceed 100 m, and with a diameter of 20 mm - 120 m. It is also desirable that the hydraulic pressure loss in the loop does not exceed 20 kPa. The approximate area occupied by one loop, subject to these conditions, is about 15 m2. At larger area collector systems are used, while it is desirable that the length of the loops attached to one collector be approximately the same.
What should be the thickness of the heat-insulating layer under the pipes of the "warm floor"?
The thickness of the thermal insulation, which limits the heat loss from the "warm floor" pipes in the "down" direction, should be determined by calculation and largely depends on the air temperature in the design room and the temperature in the underlying room (or soil). In most Western calculation programs, heat losses "down" are taken in the amount of 10% of the total heat flow. If the air temperature in the calculated and underlying room is the same, then this ratio is satisfied by a layer of expanded polystyrene 25 mm thick with a thermal conductivity coefficient of 0.035 W / (mK).
What pipes are better to use for the installation of the "warm floor" system?
Pipes for a "warm floor" device must have the following properties: flexibility, allowing the pipe to be bent with a minimum radius to ensure the required laying step; the ability to keep the shape; low coefficient of resistance to the movement of the coolant to reduce the power of pumping equipment; durability and corrosion resistance, since access to pipes during operation is difficult; oxygen impermeability (like any pipeline heating system). In addition, the pipe must be easy to process a simple tool and have a reasonable price.
The most widespread systems are "warm floor" made of polyethylene (PEX-EVOH-PEX), metal-plastic and copper pipes. Polyethylene pipes are less convenient in work, because they do not retain the given shape, and when heated, they tend to straighten up ("memory effect"). Copper pipes, when embedded in a screed, must have a polymer coating to avoid alkaline exposure, moreover, this material is quite expensive. Metal-plastic pipes most fully meet the requirements.
Do I need to use a plasticizer when pouring a "warm floor"?
The use of a plasticizer allows you to make the screed more dense, without air inclusions, which significantly reduces heat loss and increases the strength of the screed. However, not all plasticizers are suitable for this purpose: most of those used in construction are air-entraining, and their use, on the contrary, will lead to a decrease in the strength and thermal conductivity of the screed. For "warm floor" systems, special non-air-entraining plasticizers are produced, based on fine scaly particles. mineral materials with a low coefficient of friction. As a rule, the consumption of the plasticizer is 3-5 l/m3 of solution.
What is the point of using aluminum foil coated thermal insulation?
In cases where the pipes of the "warm floor" are installed in air gap(for example, in floors along logs), foiling thermal insulation allows you to reflect most of the downward radiant heat flux, thereby increasing the efficiency of the system. Foil plays the same role in the construction of porous (gas or foam concrete) screeds.
When the screed is made of a dense cement-sand mixture, thermal insulation foiling can only be justified as an additional waterproofing - the reflective properties of the foil cannot manifest themselves due to the lack of an air-solid body boundary. It must be borne in mind that the layer of aluminum foil poured cement mortar, must have protective covering from a polymer film. Otherwise, aluminum can be destroyed under the influence of a highly alkaline environment of the solution (pH = 12.4).
How to avoid cracking of the "warm floor" screed?
The reasons for the appearance of cracks in the "warm floor" screed may be the low strength of the insulation, poor-quality compaction of the mixture during installation, the absence of a plasticizer in the mixture, too thick a screed (shrinkage cracks). should be adhered to the following rules: the density of the insulation (expanded polystyrene) under the screed must be at least 40 kg / m3; the screed mortar must be workable (plastic), the use of a plasticizer is mandatory; in order to avoid the appearance of shrinkage cracks, polypropylene fiber should be added to the solution at the rate of 1-2 kg of fiber per 1 m3 of solution. Steel fiber is used for load-bearing floors.
Is waterproofing required for underfloor heating?
If a vapor barrier device is not provided for in the architectural and construction part of the project, then with the "wet method" of installing the "warm floor" system on floors, it is recommended to lay a layer of glassine over the leveled floor. This will help prevent laitance from leaking through the overlap during pouring of the screed. If the project provides for interfloor vapor barrier, then it is not necessary to arrange additional waterproofing. Waterproofing in wet areas (bathrooms, lavatories, showers) is arranged in the usual way over the "warm floor" screed.
What should be the thickness of the damper tape installed around the perimeter of the room?
For rooms with a side length of less than 10 m, it is sufficient to use a seam with a thickness of 5 mm. For other rooms, the calculation of the seam is carried out according to the formula: b \u003d 0.55 o L, where b is the thickness of the seam, mm; L is the length of the room, m.
What should be the step of laying the pipes of the "warm floor" loop?
The step of the loops is determined by calculation. It should be borne in mind that a loop pitch of less than 80 mm is difficult to implement in practice due to the small bending radius of the pipe, and a pitch of more than 250 mm is not recommended, as it leads to a noticeable uneven heating of the "warm floor". To facilitate the task of choosing the loop pitch, you can use the table below.
Is it possible to install heating only on the basis of the "warm floor" system, without radiators?
To answer this question in each case, it is required to make a thermal calculation. On the one hand, the maximum specific heat flow from the "warm floor" is about 70 W/m2 at an air temperature in the room of 20 °C. This is sufficient to compensate for heat losses through enclosing structures made in accordance with thermal protection standards.
On the other hand, if we take into account the heat costs for heating the required sanitary standards outdoor air (3 m3 / h per 1 m2 of living space), then the capacity of the "warm floor" system may be insufficient. In such cases, the use of edge zones with elevated surface temperatures along the outer walls, as well as the use of sections of "warm walls" is recommended.
How soon after pouring the screed can I start the "warm floor" system?
The screed must have time to acquire sufficient strength. Three days later in vivo hardening (without heating), it gains 50% strength, after a week - 70%. Full curing to the design grade occurs after 28 days. Based on this, it is recommended to start the "warm floor" no earlier than three days after pouring. It must also be remembered that the filling of the "warm floor" system with a solution is carried out with floor pipelines filled with water at a pressure of 3 bar.
