How to avoid the formation of icicles on roofs in winter. Why and how do icicles appear? Effective blood protection against icicles

With the onset of autumn and the accompanying cooling, icicles appear on the roofs of houses, on trees and other objects. Adults are used to seeing them and sometimes don’t even notice this phenomenon. Children show great interest in them, and sometimes not only demand to pick a couple of pieces, but also to tell where they come from.

Icicles are beautiful a natural phenomenon, despite the fact that they can be dangerous - for example, when they hang like blocks of ice on the roofs of houses, threatening to fall down at any moment. How are they formed? In fact, there are no mysteries in their appearance. Ice clusters are formed due to long-studied natural forces.

What processes form icicles?

The water outside begins to freeze at the first negative temperatures, creating ice crusts on puddles and icy conditions. It freezes not only on horizontal surfaces. Flowing vertically, an ice drop can also freeze. Moreover, in many cases it flows slowly - water molecules create surface tension forces, which help the drop to remain until a certain point on the edge of the roof, on a branch, and so on. These forces prevent the object from naturally falling down immediately, as it should due to the forces of gravity. A drop may well freeze while it hangs, and the next drop will freeze on it. This is how an icicle is formed - drop by drop.

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Under certain temperature conditions, which are usually observed in spring and autumn, as well as during the thaw period, snow can thaw on roofs under the rays of the sun, drops of water that form during this process roll down and gradually freeze. Subsequent drops, rolling down the already formed ice, also gradually cool, making the icicle more massive and longer. If frost sets in again, the icicle will remain in the form in which it managed to form on warm days, and it will hang until it falls due to its own gravity, or is knocked down by people or the wind. If warming occurs at an even more serious pace and the temperature rises, the icicle will melt naturally- exactly the same way it was formed.

Are stalactites and stalagmites icicles?

On the vaults of the caves you can see stone stalactites, as well as stalagmites or stalagmata, which are very similar to icicles. The similarity is so obvious that some people confidently consider stalactites to be ancient petrified icicles. But is it? In fact, the nature of these formations is somewhat different, although water is also “to blame” for their appearance. Seeping through rock strata earth's crust, water often erodes gypsum and limestone deposits. The water becomes hard and saturated with minerals. If such water seeps up to the cave roofs and begins to drip down, the process of mineral deposition begins, which forms stalactites.

Against the backdrop of warming winters in the last decade with thaws alternating with cold snaps, fight the formation of icicles by mechanical means has become extremely difficult. It seemed like just yesterday all the ice growths had been removed, but no - here they are, appearing again.

It is unthinkable that a utility company or owner would knock icicles off the roof every day. That is, the likelihood of accidents from falling remains high, and the coating loses its reliability. Hence the conclusion - properly organized protection of the roof from icicles is necessary.

How icicles appear: formation mechanism

The formation of icicles is based on a natural process. Melting of snow settled on the roof usually occurs for two reasons:

• under the influence of the sun's rays;
• as a result of poor thermal insulation of the roof.

The first of the processes takes place intensively in the spring: during the day the roof is warmed by the sun, and at night the snow that has managed to melt freezes again due to a sharp change in temperature.

In winter, in roofs with low thermal insulation or with attic floors, the formation of ice and icicles can occur continuously. Due to increased heat transfer, the lower layers of the roof's snow cover melt and flow into the drain. There, the melt water, being deprived, begins to freeze and forms icicles along the edge of the roof.

Over time, the icicle's own mass increases, and at some point, at the point where growth begins, the value of its strength limit is exceeded, and it collapses down.

Effective blood protection against icicles

The process of mechanically clearing snow and icicles from the roof is a rather labor-intensive task and is also fraught with damage to the coating. The best option to combat icing is cable protection.

The main thing is that it is not only effective way eliminating existing ice build-ups, but also preventing them.

Advantages of cable anti-icing systems

Such roof and gutter protection has certain advantages.

• During installation, intervention in the building structure is not necessary. It is suitable for any surface and does not spoil the appearance of the house.
• Can be laid on the roof both locally and along the perimeter.
• No dismantling is required, so it is considered ideal in seasonal climate conditions.
• Cable heating is initially designed to prevent the appearance of snow masses, and not to melt them. This approach reduces energy consumption.
• Depending on the anti-icicle cable used, the resulting additional savings vary.
• Minimizes the cost, which can be quite expensive.
• Control functions, thanks to temperature, humidity and snow sensors, are performed completely autonomously without any human intervention. In particular,

The system will work exactly as long as the risk of icicle formation remains, in other words, until the melting on the roof stops. This process itself is absent if the outside temperature is below -10°C on average or there is no snow.

Components

The anti-icing system consists of:

Heating cable

It is installed in areas most likely to cause icicles to appear, more precisely, along the edge of the roof and in the drainage system: gutters and downspouts. More precisely, the installation location is determined based on the type of roof and its thermal conditions climatic conditions one region or another. If in some cases they are limited to heating drains and gutters, then in others the cable must be laid in other areas. On average, the heating power is about 40-50 kW/m, but for each case it is calculated individually. By laying the cable in several lines, you can provide the necessary power.

Fasteners

Special fasteners ensure that when installing the cable, there are no drilling holes on the roof or pipe. For example, in the case of a soft roof, the fastening is performed on a special metal tape, which also eliminates direct thermal contact with the surface.

Control elements

These include precipitation, temperature and melt water sensors. As soon as the sensor readings record an excess of the permissible limits, the system starts. The snow layer periodically melts and moves away through the gutters.

Distribution network

Through it, a heating cable is connected to a source of electricity.

Remote Control

It is needed to control work.

Types of cable

Self-regulating– an excellent opportunity to save energy, since its power can vary according to temperature environment, and the cable power could differ in different sections. The cable is highly reliable. Its insulation made of polymer materials, even when overlapping, protects it from overheating and short circuiting, as well as from UV radiation and mechanical damage. The self-regulating one is simply mounted and does not lose its properties when cut into sections of any length.

Resistive ones are more often used in open areas, since their power is constant. During installation, it is necessary to avoid overlap so as not to cause overheating. Has certain restrictions on minimum/maximum length.

Thermal conditions of the roof structure and power calculation

When calculating the power of anti-depletion systems, the following are taken as a basis: thermal conditions roofs:

“Cold” - has a low level of heat loss and good thermal insulation. Ice dams on such roofs usually form when snow melts in the sun. The lowest melting temperature is up to -5°C. The snow melting system is installed exclusively in gutters.

“Warm” - has poor thermal insulation, the snow on it begins to melt at low air temperatures down to -10°C. Anti-icing on such roofs is complex; it is installed in gutters, gutters and on the roof. in this case, they have increased linear power (25–30 W). The power at their edges and in the gutters is set higher than in the case of “cold” ones so that the system maintains operating efficiency at low temperatures.

“Hot” - has poor thermal insulation, but is not used for technical purposes. Snow on them can melt at lower temperatures, below -10°C. This is the most difficult option for designing and installing an anti-icing system.

Nina Mikhailova

I would like to bring to your attention the wonderful stories of V. I. Morozov, which help introduce children to some natural phenomena.

How icicles grow.

March is not called fickle for nothing.

The sun will warm you during the day. The puddles on the roads glisten, the streams gurgle and shimmer, and the droplets chatter excitedly.

There will be frost at night. It will bind puddles, twist a rope around a stream, freeze icicles.

So you walk around, you don’t notice, and one morning you see a drainpipe hung with smoky icicles, And you'll be surprised: “How did this happen?”

That's how.

It's hot in the sun at noon. At least get a tan. The drops are running, the drops are rushing, the burning tears of winter are pouring.

It gets colder in the evening.

Will melt an oblique ray of sunshine will turn a snowflake into a drop. A drop rolls down the roof and cools down. From the roof to icicle and down the icicle. Slides down to the very icicle nose, just to break away and hit the pliable snow, but that was not the case.

While she was rolling down, she cooled down, but just wanted to break away - she was completely frozen.

So icicles grow in length.

The sun sinks lower, its rays warm less. The drops are running more and more lazily. They freeze higher and higher. Farther and farther from icicle nose.

So icicles grow thicker.

That's why they are covered in bumps. Each tubercle is a frozen droplet, hidden for a while, alive and cheerful.

The night will freeze the drip ringing, the snow will catch infusion. Roads will open to the farthest and most remote corners.

The morning will rise in a frosty haze. But when it warms up a little, the drops start babbling again, they start again grow icicles.

Only now it’s the other way around. First in thickness, then in length. And closer to lunch they start crying.

So all the time Icicle's life. In the morning and in the evening growing and getting fatter, and at noon he cries and loses weight.

The longer the days, the hotter the sun, the longer the drops cry icicle. He is losing more weight and becoming thinner.

Until everything is spent.

Nast.

It’s bad in a snowy forest without skis. And skiing is not easy either. The snow is deep and loose - skis fall through and their toes catch on twigs and branches. By the time you make your way through the bushes, more than one sweat will come off.

Is it the case when it comes.

Nast happens in March. When winter and spring come together and rule together. During the day the sun warms as much as it can, the snow melts - spring. At night the frost sets in, the most winter frost possible. Grabs wet snow strong thick crust.

This dense snow is present.

It's fun to run along the bell when it comes.

Crunch, crunch, crunch - echoes under the heel. No need for heavy skis. You walk like in summer, even better.

No dirt for you, no swamp hummocks. The grass doesn't get tangled in your feet. Everything is under snow: swamps, hummocks, and dead wood. And from above crust like parquet. Yes so durable that even a huge elk does not fall through.

Go wherever you want, but by lunchtime try to be closer to the road.

Otherwise it's bad.

The snow crust will become limp under the hot sun rays, you can’t even take a step here. Just right to swim in a deep snow mess.

No amount of skiing will help.

Take advantage of the features spring snow hunters and foresters. Early in the morning they all go about their business. Hunters looking for capercaillie leks, foresters to inspect, walk around distant forests. During the day they sit by the fire and drink aromatic currant tea and sunbathe. At night, in the frost, they come back home.

The article talks about why icicles appear, how to make them yourself, and what their danger lies in a big city.

Cold

On our planet there are many climatic zones. There are both hot regions and those where summer never occurs, and human life is almost impossible. In some places it almost always rains, while in others it rains very rarely, and it is difficult for their residents to imagine frequent thunderstorms, much less water in its non-liquid state - snow and hail.

But all cold areas and places where the temperature drops below zero in winter have one more familiar phenomenon in common. These are icicles. So why do icicles appear? First you need to figure it out and ice.

Definition

According to generally accepted terminology, cooling is a phenomenon that occurs as a result of a decrease in temperature or removal of heat from an object in one way or another. For most living forms low temperatures destructive, just like high ones. And by the way, absolute cold is designated as -273.15 degrees Celsius. Under such conditions, not only does water freeze, but also metals become brittle, like glass, and the movement of elementary particles in matter practically stops.

Ice

When the temperature drops below zero degrees Celsius, water turns into ice. It is the solid state of a substance that would normally have a liquid form. But if there is no rain in winter and all the liquid freezes, then why do icicles appear on the eaves of houses? The thing is that during winter periods the temperature can vary over fairly wide ranges, and the precipitation will begin to melt, and then the return of frost will stop this. That is why the water that was snow begins to drain from the roofs of houses, and as the temperature drops, it gradually freezes, which is why the drops, sliding along the bases of the icicles, do not reach the ground in full, leaving part of the liquid in the form of ice.

But sometimes in winter there is no above-zero temperature at all, but ice can still be observed. Why do icicles appear in this case?

Warm

In this case, home heating comes into play. According to statistics, in winter, most houses lose up to 30% of heat through the roof, and the snow, albeit slowly, still melts. This is especially true in private homes.

Danger

These ice formations are quite great danger. Especially in cities where there are many high-rise buildings. And all because getting to their eaves is very problematic, and icicles sometimes grow to enormous sizes. As a result, a fall can kill a bystander. And, let’s face it, getting hit on the head with even a small piece of ice falling from the 15th floor is not a pleasant experience.

Therefore, every winter, utility services spend a lot of effort trying to knock down icicles.

How to make an icicle?

There are several ways. The first one is the most “natural”. On a frosty day, you need to be patient and have a bottle of water. Then find an object on the street from which the liquid would drain slowly and evenly, and ideally drop by drop. This process is slow, but with the appearance of the first ice, things will become more fun.

The second way is to make it at any time of the year. You just need to prepare the appropriate form, fill it with water and place it in the refrigerator freezer. But the main thing to remember here is that liquid expands greatly when it freezes and can destroy the mold material, so glass is not suitable for it.

Well, the third thing is to get a block and cut a narrow long cone in the form of an icicle from it. True, it will not be an icicle in the usual sense, since dry ice consists of frozen carbon dioxide, which does not melt, but evaporates. It can also cause cold “burns” on the skin.

Now we know how icicles appear, and we have also learned how to make them.

How often have you wondered why icicles hang from roofs and canopies in winter, and how they form?

Icicle formation.

We all know that at temperatures below zero degrees Celsius, water freezes and turns into ice. The water that was snow on the roof begins to slowly melt and drain when the temperature rises, and when the temperature drops it freezes, turning into an icicle. In this case, not all drops of water, rolling down the icicles, manage to reach the ground. Such temperature changes occur for various reasons, here are some of them:

- at night the temperature can be below zero, and during the day above

— during the day the snow begins to melt under the rays of the sun

- and the main reason is that even if the temperature outside is sub-zero, then in some rooms (usually in old houses) under the roof it is warmer (above zero) and the lower layer of snow begins to melt and flow to the drains.

Fighting icicles.

Today, there are many ways to combat icicles on the roofs of buildings. These methods are divided into two main types. The first - actual - removal of already formed icicles on the roof overhangs. The second type is preventive - thermal insulation of attics, ventilation of buildings, reconstruction of roofs and gutters. This method involves keeping attics cold and prevents the formation of icicles.

Do not forget that when there is a thaw or under the weight of their own, the icicles begin to fall; be careful, do not walk under the roofs of buildings.