With the beginning of the warm spring months, mass construction starts in Russia: owners of dachas, private houses and personal plots begin to renovate their farms. Many people use asbestos-based thermal insulation materials for their new baths or heating systems. This mineral has high performance properties: it does not burn, has low thermal conductivity, does not melt and does not emit harmful fumes. asbestos safe for human health when heated? We will talk about this in this article.
Russian emergency services personnel recommend using asbestos materials to ensure the safety of heating structures in the house.
What it is?
Information about its characteristics will help you find out whether asbestos is harmful. As you know, this name hides several materials belonging to silicates of natural origin. Huge reserves of one of them, chrysotile, were discovered in the Urals. This mineral has a fibrous structure: thin tubes form flexible bundles. For this reason, it has excellent technological characteristics:
- fire resistance;
- low electrical conductivity;
- heat resistance;
- significant strength;
- resistance to the influence of ozone, oxygen, radiation.
Important! After processing, fine-fiber chrysotile fluffs up greatly and acquires a unique ability to absorb other chemicals.
Asbestos or mountain flax is the collective name for a group of fine-fiber minerals from the class of silicates Source focus.ua
In nature, there are 2 types (different in structure, shade, composition) of asbestos: amphibole, chrysotile. The first one is considered more dangerous, which is why its production and use are now prohibited everywhere. Further in the article the harm of chrysotile asbestos to health will be considered. Despite the fact that such a mineral is less dangerous, it is considered a carcinogen with a special mechanism of action.
The main feature of chrysotile asbestos (asbestos crumbs) is its ability to withstand high temperatures: it does not lose its properties even at +500°C, and begins to melt at + 1500°C. Source rti.group
What is the best temperature to set in the refrigerator? How to set the temperature in the refrigerator
All refrigerator models have one of two ways to regulate the temperature in the chamber: electronic and mechanical. In the first case, there is a display on or above the main compartment door. You can set the exact temperature using keys or touch controls.
The mechanical version is more difficult. To set the temperature in the refrigerator there is a round regulator. It is located in the chamber near the light bulb or outside above the shutter. There is a scale on it or nearby. Usually it has from 5 to 9 values. The higher the number, the more the chamber cools.
Mechanical temperature controller in the main chamber of the refrigerator near the lamp
The numbers on the scale do not correspond to the temperature in degrees. Therefore, in order to install it in the refrigerator accurately, you will have to remember the mathematics. You also need to read the instructions or specifications for the refrigerator.
First you need to find within what limits the refrigerator operates. For example, your model has a range from +2 to +6 °C. We calculate the difference between them and get a value of 4 degrees. After this, count the number of spaces between scale divisions. In the photo above there are 9 divisions and 8 spaces (we also count Min and Max).
Then divide the temperature range by the number of intervals. In our case, divide 4 by 8 and get 0.5. This number is the number of degrees by which the temperature rises or falls when the dial is turned 1 notch. Now you know how to set the temperature in the refrigerator.
Where is it used?
Due to its low cost and unusual properties, asbestos is widely used in many industries:
- mechanical engineering;
- construction;
- pharmaceuticals;
- textile, chemical, aviation industries;
- rocket science.
Chrysotile is often used in the manufacture of:
- facade panels;
- rubber elements;
- roofing (slate);
- all kinds of products for the construction of walls;
- thermal insulation materials;
- sealing agents;
- asbestos technical parts;
- protective layers;
- bricks;
- adhesives, mounting, lubricants and other compounds.
Attention! The harm of asbestos to human health largely depends on the frequency of contact of the respiratory tract with harmful asbestos dust.
The addition of asbestos to various building materials gives them high fire resistance and excellent thermal insulation properties Source o-remonte.info
When are sheet fireproof materials used?
It is not always necessary to use protective materials, but only in cases where the fire-safe distance from the stove surface to flammable objects is not maintained. If the distance is large enough, the wood does not heat up enough to cause a fire.
Modern standards require that a brick stove be located at least 32 cm from the wall, a non-lined metal stove at least 1 m, and a lined metal stove at least 70 cm.
For a spacious room, such requirements are quite feasible. But in a small home steam room it is not possible to provide a distance of 1 m. Therefore, fire safety can only be achieved with the help of fire-resistant screens and cladding.
Effect on the body
As a rule, chrysotile poisoning develops over a long period of time. As a result of its accumulation in organs, various structural disorders occur. When such a mineral is mechanically destroyed or during its manufacturing process, asbestos dust is formed. After inhalation, the fine fibers penetrate into the lungs. But due to the property of chrysotile to dissolve intensively in an acidic environment, its excessive accumulation in the organ requires prolonged contact with dust particles. Even under such circumstances, the health hazards of asbestos sometimes become apparent only after ten or more years.
As a result of mechanical irritation of the respiratory system, bronchitis most often develops. But there is also a possibility of asbestosis, since dust settled in the lungs provokes scarring in the sensitive tissues of the organ.
If we consider how asbestos is harmful in terms of oncology, it is worth noting: chrysotile itself is not an aggressive carcinogen, it only contributes to the harmful effects of other carcinogenic substances on healthy cells of the body. There is an assumption that such a mineral provokes the occurrence of a rare cancer - mesothelioma.
According to recent research by scientists, the likelihood of developing cancer due to chrysotile in production is approximately 1 in 100,000 people. This information allows you to conclude how harmful asbestos is and whether it should be avoided.
Important! After the adoption of new acceptable standards and tightening of sanitary rules at Russian asbestos mining enterprises, no cases of asbestosis have been recorded over the past two decades.
It has been established that asbestos emissions are directly related to such a rare disease as mesothelioma (a type of cancer) Source static.tildacdn.com
What temperature? What temperature is considered normal?
What should be the normal temperature for a healthy adult? In medicine, 36.6°C is considered normal. This value is not constant; during the day it increases and decreases, but only slightly. There is nothing to worry about if the temperature drops to 35.5°C or rises to 37.5°C, since its fluctuations are greatly influenced by climatic conditions, age and well-being of a person. In people of different ages, the upper limit of normal temperature measured in the axillary fossa is different and has the following values:
- in newborn babies – 36.8°C;
- in six-month-old babies – 37.5°C;
- in one-year-old children – 37.5°C;
- in three-year-old children – 37.5°C;
- in six-year-old children – 37.0°C;
- in people of reproductive age – 36.8°C;
- in older people – 36.3°C.
Usually during the day the body temperature of a healthy person fluctuates within one degree.
The lowest temperatures are observed in the morning immediately after waking up, and the highest in the evening. It should be borne in mind that the female body temperature is on average 0.5°C higher than the male body, and can vary significantly depending on the menstrual cycle.
It is interesting to note that representatives of different nationalities have different body temperatures. For example, in most healthy Japanese people the body does not heat above 36.0°C, and in the inhabitants of the Australian continent the temperature is considered to be 37.0°C. Human organs also have different temperatures: the oral cavity – from 36.8 to 37.3°C, the intestines – from 37.3 to 37.7°C, and the hottest organ is the liver – up to 39°C.
Prevention of poisoning
Today, the answer to the question of whether asbestos is harmful to health is already obvious and beyond any doubt. Therefore, it is extremely important to remember that the use of amphibole mineral is strictly prohibited under any circumstances. When using the more common chrysotile, the following instructions must be observed:
- when coming into contact with asbestos materials, use protective equipment;
- waste and dust should be stored in a sealed container, then disposed of using a special technology;
- use only dense products: they should not crumble;
- the mineral cannot be sprayed in the air;
- periodically monitor the permissible level of asbestos fibers in the production area;
- undergo regular medical examination.
When working with building materials that contain asbestos, it is extremely important to protect the respiratory system Source laboratoria.by
Protective screens for furnaces
Protective screens are structures used to insulate the side walls of furnaces. They reduce thermal radiation. Protective screens are made of brick and steel. Mostly such designs are used for metal furnaces.
Oven with metal protective screen
The easiest way to build a protective screen for a furnace with your own hands is from sheets of cast iron and industrial steel. Such screens are the most common. The sheets are installed at a distance of 1-5 cm from the walls of the oven.
How to replace asbestos
Multiple studies prove that the use of chrysotile is undesirable. To replace it, it is recommended to use the following building materials:
- extremely heat-resistant asbestos boards can be replaced with thermal protection made of silica, basalt panels, mullite-silica wool;
- Minerite is perfect for decorating fireplaces;
- slate is easily replaced with safe, more durable metal tiles and corrugated sheets;
- Facade asbestos-cement products can be replaced with similar fiber-cement products, the latter are considered less harmful.
Any asbestos product can be found with a safe and reliable replacement that will have similar characteristics. Source xn—-dtbegn3a5abh8i.xn--p1ai
When heated, the health hazards of asbestos do not increase. But experts do not recommend using it for arranging fireplaces for a completely different reason. Decorating home heating structures with such a mineral is tantamount to containing a carcinogen inside a living room in a completely open state. At the same time, the likelihood of releasing harmful asbestos dust into the environment increases significantly. You should also refrain from using asbestos in the construction of a bathhouse. Instead, you can purchase foil-coated basalt wool.
At first, chrysotile intoxication is not noticeable at all. Its negative consequences are often observed many years later, when a person is diagnosed with dangerous diseases. Therefore, you should not neglect your health; you should listen to the recommendations of specialists, protect yourself and your loved ones from hidden dangers.
Advice! The use of asbestos-containing products in domestic conditions should be reduced as much as possible. When this cannot be avoided at all, it is necessary to carefully check whether building materials are certified for safety. All of them must be subject to wet processing, as well as disinfection using special chemical compounds.
Despite the fact that asbestos is recognized as a dangerous carcinogen, builders sometimes continue to use materials containing it Source golos.ua
Application of asbestos cardboard and its technical characteristics
Content:
Industrial production is always associated with energy consumption. To reduce production costs, thermal insulation of construction sites and equipment is carried out. As a result, reducing the cost of energy produced leads to increased production profitability. There is a whole range of thermal insulation materials on the market. However, despite their diversity, most insulation materials have great limitations in application. Most insulation materials contain flammable components or toxic polymers. This does not allow their use in structures where increased fire resistance is required.
For thermal insulation and fire protection, it is advisable to use asbestos cardboard. The use of this insulating material will reduce fuel/energy consumption. It becomes possible to reduce the costs of thermal power equipment, since it is possible to reduce its power and increase productivity through high-quality thermal insulation.
Characteristics of asbestos cardboard
Asbestos cardboard is an insulating sheet material with fire-resistant properties. It consists of 98-99% chrysolite asbestos and 1-2% starch impregnated with bakelite. Asbestos cardboard, along with fire resistance, has a number of distinctive characteristics from other insulating materials, these are:
- durability;
- high strength;
- reliability;
- resistance to alkalis;
- mechanical strength;
- stability of thermal insulation ability;
- resistance to infection by microorganisms;
- good adhesion (with wet installation method).
Asbestos sheet KAOH-1 is used for thermal insulation of equipment and objects with temperatures not exceeding 500°C. Brand KAOH-2 is used as a sealant for detachable connections of devices and pipelines under pressure up to 600 kPa. The density of asbestos cardboard grades KAOH-1 and KAOH-2 is in the range: 1000 – 1400 kg/m3. Tensile strength of KAOH-1, when tested in tension perpendicular to the direction of the fibers: 600 kPa or more, KAOH-2 – 900 kPa or more. Tensile strength of KAOH-1, when tested in tension along the direction of the fibers: 1200 kPa or more, KAOH-2 – 1500 kPa or more. Mass fraction of moisture: KAOH-1 – no more than 7%; KAOH-2 – no more than 10%. Asbestos board sheets have a thickness of 3 to 10 millimeters.
The weight loss upon ignition is no more than 15% for both brands.
Scope of application of asbestos cardboard
Asbestos cardboard is used for thermal insulation of equipment, facilities and communications. Including those where protection against fires and fires is necessary. Asbestos cardboard is a non-flammable material. The physical and mechanical properties of asbestos sheets hardly change when heated. Asbestos cardboard can be used on surfaces of equipment and communications with temperatures up to 500 C°. There are no toxic emissions when heated. It is practical to use this material as thermal insulation for furnaces and boilers in industrial enterprises. The use of asbestos sheets reduces the heat transfer of insulated objects, significantly lowers the surface temperature of equipment, improves sanitary conditions in the work area, and reduces the amount of heat that is spent on heating the masonry. As a result, inertia is reduced. This is especially true for equipment that needs to be stopped frequently. Reducing inertia allows you to reduce not only heat loss, but also the time for heating and cooling. Sheet asbestos is used to level air ducts and gas pipelines, and to level surfaces for masonry. They perform thermal insulation between the lining and the outer casing in furnaces. They isolate frame blocks from lining in boilers. I use it as a leveling layer under fiberglass when insulating pipes. In mechanical/instrument making and radio electronics, soundproofing and electrical insulation materials are made from asbestos cardboard. Such materials are non-flammable and non-toxic. Asbestos cardboard of the KAOH-2 brand is used to seal detachable devices, devices, pipelines operating under a pressure of no more than 600 kPa.
Limitations of asbestos cardboard on permissible temperatures:
- for gas – 500 C°;
- for alkalis – 200 C°;
- for inorganic acids – 120 C°;
- for organic compounds, melts and salt solutions – 400 degrees Celsius.
In civil engineering, asbestos cardboard is used as a cheap and practical fireproof and flame retardant material.
Installation of asbestos cardboard
A notable feature of asbestos cardboard is its ease of use; this is an undeniable advantage of a heat insulator over other materials. Installation of sheet asbestos is carried out without the use of special tools. Also, no special skills or specific training are required for personnel performing thermal insulation work. Fitting and installation are easy. The material is easy to saw, drill and other types of machining. The most rational way to cover the surface with asbestos sheets is laying with preliminary soaking. Thanks to its plasticity and high degree of adhesion, the cardboard fits tightly to the surface, securely fixing to it after drying. Using this technique, it is possible to qualitatively cover both smooth surfaces and objects with complex spatial configurations. The plasticity of moistened asbestos cardboard makes it possible to ensure a tight fit at corners, irregularities and breaks in the surface. The shape formed during the laying process is preserved, the cardboard does not deform or warp during drying.
Moistened asbestos cardboard dries quickly, which reduces the intervals between construction and installation works, which reduces non-production losses and minimizes the time required for work.
Advantages of asbestos cardboard
Chrysolite asbestos has high mechanical strength. Thanks to this quality, the heat insulator made on its basis is little susceptible to deformation. As a result, it does not change its characteristics under mechanical influence. Mechanical strength is ensured by the structure of the material. Even when exposed to high temperatures, the sheets retain their physical properties without significant changes. Asbestos is insoluble in water, does not rot, and is resistant to alkaline environments. The listed qualities of asbestos cardboard allow us to consider it as a material with a long service life. The durability of the heat insulator is comparable to the service life of the materials used to manufacture equipment and facilities. Naturally, subject to the installation and operation rules.
Compared to other common materials for thermal insulation, asbestos cardboard differs for the better in such characteristics as:
- static volume;
- the possibility of applying a layer of glue to the surface;
- long shelf life;
- Possibility of storage at subzero temperatures;
- when insulating vertical structures, it does not settle or flow;
- short duration of work;
- stability of the quality of work performed.
Insulating boilers, as well as furnaces, with asbestos cardboard makes it possible to minimize the thickness of enclosing structures. Consequently:
- the volume of lining material is reduced;
- the volume and weight of the oven decreases;
- foundation requirements are reduced;
- the free space of the premises in which furnaces or boilers are located increases;
- Construction and reconstruction of boilers takes less time and does not require large labor costs.
Transportation and storage
Workers carrying out any manipulations with asbestos cardboard must work in special clothing and special shoes. Must have with them, be able to use and apply personal protective equipment as intended. When performing work, it is necessary to protect exposed skin with dermatological agents. Respiratory organs are protected from asbestos dust by mechanical means. A “Petal” respirator or other means providing protection against mechanical particles in the air is used. Each batch of asbestos cardboard is supplied with a quality certificate. Where indicated:
- manufacturer's name;
- brand;
- Net weight;
- batch number;
- dimensions of sheets and pallets;
- State standard to which a given batch of asbestos board or test results corresponds.
It is also not allowed to form a batch in sheets of different sizes. The total weight should not exceed five tons. Upon acceptance of each batch, the sheets are subject to external inspection. At least ten pieces are selected from the batch for visual inspection. The product must not have mechanical damage or foreign inclusions. The surface may have longitudinal grooves or imprints of interlining fabric. Which is not considered a defect. The edge of the sheet should be straight. For the KAOH-1 brand, edge breaks and tears up to two centimeters long are acceptable. Transportation is possible either packaged or unpacked. It is recommended to use shipping containers, but at the customer’s request, asbestos cardboard can be delivered without using packaging. Sheets are usually sorted by size and stored in wooden boxes. Pre-packed in sack paper or plastic bags. When storing on pallets or boards, the pallets are tied with polymer or steel tape. This material is stored in closed warehouses. Since in open areas the sheets may become contaminated with water or other liquids.
The guaranteed shelf life, subject to the necessary conditions, is ten years.
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