Thermal conductivity and density of glass, properties of porcelain, earthenware, crystal

Glass is the oldest and most versatile material that is used in various fields of human activity. Glass production began in Ancient Egypt, where glass was used for the interior cladding of pyramids. A little later, glass began to be widely used in the decoration of many palaces. The most important characteristics of glass remained hardness, strength, thermal conductivity and high heat resistance, and these characteristics can affect the quality of this material.

Thermal conductivity of glass at different temperatures

The table shows the values ​​of the thermal conductivity coefficient of glasses of various densities depending on temperature.
The thermal conductivity of glass is given at negative and positive temperatures - in the range from 4 to 1140 K (-269...867 ° C). The following types of glass are considered: quartz glass (fused quartz), crown glass (light LK5 and barite series 100BK110), borosilicate glass (C38-1, C39-1, C47-1, Pyrex), sodium-lime, refractory lead, porcelain, earthenware, flint (heavy TF1 and barite BF8), crystal with a density of 2600...2850 kg/m3.

The thermal conductivity of various types of glass at room temperature ranges from 0.7 to 1.6 W/(m deg). For example, the thermal conductivity of quartz glass at room temperature is 1.36 W/(m deg) ; the thermal conductivity of crystal is in the range of 0.88-0.91 W/(m deg); The thermal conductivity of porcelain is 1.68 W/(m deg).

At low negative temperatures, glass has a thermal conductivity of 0.13-0.4 W/(m deg). As the temperature of glass increases, its thermal conductivity increases. At high temperatures, the thermal conductivity of glass increases to a value of 2-2.25 W/(m deg).

Note: The thermal conductivity dimension in the table is W/(m deg), all samples are annealed, the thermal conductivity of the glass corresponds to the temperatures indicated in the table, data interpolation is possible.

Glass Density

The table shows the density values ​​of common glass types at temperatures from 0 to 50°C in kg/m3 dimensions. It should be noted that the density of glass is in a wide range - from 2180 to 8000 kg/m3 and depends on the composition of the glass, its temperature and heat treatment mode.

Low density glasses include: Vicor, quartz glass, Pyrex. The density of ordinary window glass is about 2500 kg/m3, which is comparable to the density of aluminum alloys. High-density glass includes glass containing heavy metal oxides. For example, glasses with a high content (up to 80%) of barium oxides BaO and lead PbO, bismuth, thallium, and tungsten have a density of about 8000 kg/m3 - their specific gravity can exceed the density of steel.

It should be noted that the density of glass depends on temperature. When glass is heated, its density decreases due to an increase in volume due to thermal expansion. During the heating process, the density of glass decreases by an average of 7.5 kg/m3 for every 50 degrees of temperature.

Heat treatment also affects the density of glass. During the process of tempering and annealing glass, its internal structure changes. During hardening, the state of the high-temperature structure of the melt is fixed, which has a larger volume than the structure of glass subjected to prolonged annealing. As a result of heat treatment, the density of tempered glass becomes 4-5% lower compared to annealed glass.

The density of glass or glass products can be determined experimentally with high accuracy using the pycnometer method or using hydrostatic balances.
The hydrostatic weighing method is based on Archimedes' law and comes down to determining the volume of liquid displaced by glass. Glass density in kg/m3

The following table shows the density of optical colorless glass of common brands according to GOST 3514 at room temperature.
Density of optical glass of common brands

Read on to find out more!

2.64

Rating: 2.6 out of 5 Votes: 233

5

Reply 5 years ago

Max

5 years ago Quote

I will share my experience. When I decided to install plastic in my house, I was guided solely by the price and a strange, as I already understand, logic. Before this, they were wooden and I thought that even the cheapest double-glazed window would make the house warmer; it simply couldn’t get colder. Yes, the house has become warmer. But due to lack of experience, I did not take into account the condensate. This is a real disaster. Okay, if the windows are just foggy, you can wipe it down and that’s it. The walls around them began to sweat and peel. Ventilation did not help, and the heat was leaving the house. So we had to remove and install double-glazed windows. This is how I “saved.”

5 years ago Quote

4 years ago

Vladimir

4 years ago Quote

I have had a single-chamber double-glazed window (Veka) in my kitchen for more than five years and, in comparison with a double-glazed window in the bedroom, it has only advantages. Yes. It is very easy to determine how many glasses and, accordingly, chambers in a double-glazed window - light a match and count the lights in the glass. A single-chamber one will have two lights, and a two-chamber one will have three, respectively.

Sergey

4 years ago Quote

Every year it’s the same thing, painting wooden windows and stamping stamps. One year I was lazy with painting, so the frame dried out and from the strong wind from the second floor the glass fell out and fell next to the car, but did not catch significantly. I ran around all the retail outlets selling metal-plastic windows. I found the most reasonable price, they advised me not to buy it there, they say, the quality is poor, it needs to be a five-chamber profile and a glass package with three glasses. At my own peril and risk, I took the usual single-chamber ones, I was very pleased, they don’t leak in winter, the lock mechanism is strong, it presses the window tightly to the frame. The only negative: the seams in the profiles are rough and you have to use force to open the window; a child cannot open it on his own. In general, the house became lighter and warmer in winter.

Specific heat capacity of glass

The table shows the specific heat capacity of glass of various types and densities depending on temperature. The thermal capacity of glass is given in the temperature range from 173 to 1473 K (-100...1200 °C). The dimension of heat capacity in the table is kJ/(kg deg).

The specific heat capacity of the following glasses is given: quartz glass, crown glass, sodium glass, window glass, pyrex glass, thermometric glass, flint glass, glass made from natural silicates: anorite, albite, wollastonite, diopside, microcline.

The specific heat capacity of glass of the main types is in the range of 490…1125 J/(kg deg). For example, the specific heat capacity of silicate glasses ranges from 300 to 1050 J/(kg deg) and depends on the composition of the glass . Low heat capacity is characteristic of glasses with a high content of heavy elements - such as barium or lead - this applies primarily to heavy crowns and flints. Glasses with high heat capacity at ordinary temperatures include: Pyrex, soda glass, and thermometric glass.

It should be noted that the specific heat capacity of glass depends on temperature - when the glass is heated, its value increases. For example, the specific heat capacity of quartz glass at a temperature of 1200°C is 25-30% higher than this value at 20°C.

Where is it advisable to install single-chamber structures?

Tempering glass
There are situations where the installation of such windows is not only acceptable, but even necessary. Let's consider these cases.

Balconies and loggias

If you do not plan to make the balcony a living room, it is enough to choose a single-chamber version. The fact is that in this case the loggia will still remain a cold place. And it makes absolutely no sense to pay extra for a window with two cameras.

Dacha, summer house

If you are looking for suitable glazing for a country house, you should calculate and weigh everything correctly. In the case where the dacha will be used only in the summer, you can limit yourself to one camera. By the way, currently the cost of such a window is not much higher than classic wooden frames. And PVC is in any case much stronger and more durable.

Terrace

As a rule, this part of the house is used only in summer. Is it worth installing structures with two chambers here? Perhaps this is an unnecessary overpayment.

Apartments and houses in the southern regions

The choice of window also depends on the temperature outside the window. If in winter it does not drop below zero, a single-chamber product is sufficient. In other cases, it is advisable to install two-chamber analogues with three glasses.

Thus, the double-glazed window has an important task: to protect the house from drafts, cold and noise.

It is important to calculate whether in a particular situation it is worth paying extra for two cameras. Often, one camera is enough

Therefore, the costs will be lower, the house will be brighter, and this model will last much longer.

manufactures, sells and installs single-chamber double-glazed windows. All our products meet the strict requirements of sound and heat insulation, as well as being durable and attractive.

Before ordering such windows, please ask our managers about the feasibility of such a choice. We will advise you on this issue, taking into account the specific operation of the structures and help you make a choice. Call now!

Heat capacity, composition and other physical properties of porcelain

The table shows the composition, thermal and physical properties of porcelain at room temperature. Porcelain properties are indicated for the following types: installation, low-voltage, high-voltage and chemical-resistant porcelain.

The following properties of porcelain are presented:

• composition of porcelain;
• Mohs hardness;
• specific heat capacity of porcelain, kJ/(kg deg);
• thermal conductivity of glass, W/(m deg);
• electrical resistivity Ohm m;
• breakdown voltage, kV/mm;
• fire resistance limit, K.

Particularly noteworthy is the property of porcelain, such as heat capacity. The specific heat capacity of porcelain ranges from 750 to 925 J/(kg deg) . Installation porcelain has the highest heat capacity, and chemically resistant porcelain has the lowest.

Distinctive features of plexiglass

Glass cutting

Plexiglas has a number of advantages that are successfully used in a variety of areas of production. The main ones are:

• strength - unlike ordinary glass, acrylic is very difficult to break, so many formerly glass items are now made from plexiglass;
• easy processing - this property is widely used in design; the most incredible shapes can be created from plexiglass, which is successfully used in the production of furniture and interior items;

• low weight facilitates the transportation and installation of acrylic products; this property is used in the creation of advertising structures, plumbing fixtures, and furniture;
• a high degree of transparency in combination with different colors gives an original effect, which is also used by designers;
• moisture resistance and resistance to many chemicals allow the material to be used for the production of kitchen furniture.

In addition, it requires special care; for example, alcohol and acetone cannot be used for processing. But despite some “inconveniences”, organic glass has firmly entered our lives and is capturing more and more new areas.

Thermophysical properties of earthenware

The table shows the thermophysical properties of earthenware at room temperature. The properties of faience are given for the following types: clay, lime faience, feldspathic faience: household, sanitary.

The table shows the following properties of earthenware:

• density of earthenware, kg/m3;
• porosity, %;
• coefficient of thermal expansion (CTE), 1/deg;
• compressive strength, kg/cm2;
• bending strength, kg/cm2;
• thermal conductivity of earthenware, W/(m deg).

Sources:

1. Physical quantities. Directory. A. P. Babichev, N. A. Babushkina, A. M. Bratkovsky and others. Ed. I. S. Grigorieva, E. Z. Meilikhova. - M.: Energoatomizdat, 1991. - 1232 p.
2. Glass: Directory. Ed. N. M. Pavlushkina. M.: Stroyizdat, 1973.
3. Chirkin V.S. Thermophysical properties of nuclear technology materials.
4. Sentyurin G. G., Pavlushkin N. M. et al. Workshop on glass and ceramic glass technology - 2nd ed. reworked and additional M.: Stroyizdat, 1970.
5. GOST 13569-78 Colorless optical glass Physico-chemical characteristics. Main settings

Preface

Preface

The goals, basic principles and basic procedure for carrying out work on interstate standardization are established in GOST 1.0-2015 “Interstate standardization system. Basic provisions" and GOST 1.2-2015 "Interstate standardization system. Interstate standards, rules and recommendations for interstate standardization. Rules for the development, adoption, updating and about the Institute of Glass", Technical Committee for Standardization TC 41 "Glass"

2 INTRODUCED by the Federal Agency for Technical Regulation and Metrology

3 ADOPTED by the Interstate Council for Standardization, Metrology and Certification (protocol dated September 25, 2022 N 103-P)

The following voted for adoption:

4 By Order of the Federal Agency for Technical Regulation and Metrology dated March 27, 2022 N 149-st, the interstate standard GOST 9553-2017 was put into effect as a national standard of the Russian Federation on March 1, 2022.

5 INSTEAD GOST 9553-74

Information about changes to this standard is published in the annual information index “National Standards”, and the text of changes and amendments is published in the monthly information index “National Standards”. In case of revision (replacement) or cancellation of this standard, the corresponding notice will be published in the monthly information index “National Standards”. Relevant information, notices and texts are also posted in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet (www.gost.ru)