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Vacuum glass standard

Vacuum glass standard JC/T1079-2008

1 Scope

This standard specifies the terms and definitions, classification, requirements, test methods, inspection rules, packaging, marking, transportation, and storage of vacuum glass.

This standard is applicable to vacuum glass used in construction, household appliances and other thermal insulation, sound insulation and other purposes, including vacuum glass used in laminated, hollow and other composite products.

2. Normative references

The clauses in the following standards have become clauses of this standard after being quoted in this standard. For dated reference documents, all subsequent amendments (excluding errata content) or revisions do not apply to this standard. However, all parties that have reached an agreement Based on this standard are encouraged to study whether to use the latest versions of these documents. For undated reference documents, the latest version is applicable to this standard.

GB/T1216 outside micrometer

GB/T 8170 Numerical rounding rules

GB/T8484 Classification and inspection method of thermal insulation performance of exterior windows of buildings

GB/T8485 Classification and inspection method of air sound insulation performance of exterior windows of buildings

GB11614 float glass

GB/T11944-2002 insulating glass

JB/T7979 feeler gauge

3 Terms and definitions

The following terms and definitions apply to this standard.

3.1

Vacuum glazing

Two or more sheets of flat glass are separated by supports, and the periphery is sealed between the glass to form a glass product with a vacuum layer.

3.2

Vacuum end cap

A protective device made of metal or organic materials attached to the vacuum glass exhaust port.

 

3.3

Pillar

Inorganic material supported by skeleton in vacuum glass.

 

4 categories

4.1 Classification of vacuum glass

Vacuum glass is divided into grade 1, grade 2, and grade 3 according to thermal insulation performance. See 6.10 for specific requirements.

 

5 materials

The quality of the original sheet constituting the vacuum glass should meet the requirements of first-class or above (including first-class) in GB11614, and the quality of other materials should meet the technical requirements in the corresponding standards.

 

6 requirements

6.1 General

6.1.1 The technical requirements of vacuum glazing shall comply with the corresponding provisions in Table 1.

Table 1 Technical requirements and corresponding clauses

Project technical requirements test method

Thickness deviation 6.2 7.1

Dimensions and allowable deviation 6.3 7.2

Edge processing 6.4 7.3

Cap 6.5 7.4

Support 6.6 7.5

Appearance quality 6.7 7.6

Edge banding quality 6.8 7.7

Curvature 6.9 7.8

Vacuum glass insulation performance 6.10 7.9

Radiation resistance 6.11 7.10

Climate cycle durability 6.12 7.11

High temperature and humidity durability 6.13 7.12

Sound insulation performance 6.14 7.13

6.2 Thickness deviation

6.2 Thickness deviation

According to 7.1, the thickness deviation of vacuum glass should meet the requirements of Table 2.

6.3 Dimensions and allowable deviations

Table 2 The allowable deviation of thickness in millimeters

Allowable deviation of nominal thickness

≤12 ±0.4

>12 To be agreed between the supplier and the demander

 

6.3.1 Dimensional deviation

Perform inspection according to 7.2. For rectangular vacuum glass products, the allowable deviation of the length and width dimensions should meet the requirements of Table 3.

Table 3 Dimensions allowable deviation unit is mm

Length of nominal thickness side L

L≤1000 1000<L≤2000 2000<L

≤12 ±2.0 +2.0

-3.0 ±3.0

>12 ±2.0 ±3.0 ±3.0

 

6.3.2 Diagonal difference

Perform inspection according to 7.2. For rectangular vacuum glass products, the diagonal difference should not be greater than 0.2% of the average diagonal length.

6.4 Edge processing quality

Perform inspection according to 7.3. The edge processing of vacuum glass should be ground and chamfered, and no defects such as cracks are allowed.

6.5 Cap

When the vacuum glass is used alone, the suction hole should be protected with a cap.

Carry out inspection according to 7.4, and the height and shape of the vacuum glass sealing cap shall be negotiated between the supplier and the buyer.

6.6 Support

According to 7.5, the supports should be evenly arranged in the form of a square matrix. The arrangement quality of the support should meet the requirements of the table

4 regulations.

Table 4 Arrangement quality of supports

Defect types and quality requirements

Continuous vacancies are not allowed, non-continuous vacancies are not allowed to exceed 3 per square meter

Overlap not allowed

No more than 3 per square meter

 

6.7 Appearance quality

According to 7.6, the appearance quality of vacuum glass should meet the requirements of Table 5.

 

Table 5 Appearance quality of vacuum glass

Defect types and quality requirements

Slight scratches with a scratch width of less than 0.1mm, and when the length is ≤100mm, 4 pieces per square meter are allowed

For scratches with a width of 0.1mm~1mm and a length ≤100mm, 4 pieces per square meter are allowed

The burst edge is allowed to have a length of no more than 10mm per meter of side length, from the edge of the glass to the surface of the glass plate to a depth of no more than 2 mm, and from the plate surface to the glass thickness to extend to a depth of no more than 1.5 mm.

Smudges on the inside are not allowed

Cracks are not allowed

6.8 Edge banding quality

Carry out inspection according to 7.7, the fusion-sealed seam after edge sealing should be kept full and flat, and the effective sealing edge width should be ≥5mm.

 

6.9 curvature

According to 7.8, the curvature of the vacuum glass should meet the requirements of Table 6.

Table 6 curvature of vacuum glass

Glass thickness d (mm) Bow curve

≤12 0.3%

>12 To be agreed between the supplier and the demander

6.10 Insulation performance of vacuum glass (K value)

According to 7.9, the insulation performance of vacuum glass is divided into three levels according to Table 7.

Table 7 Insulation performance of vacuum glass

Level K value (W/(m2•K))

1 K≤1.0

2 1.0<K≤2.0

3 2.0<K≤2.8

6.11 Radiation resistance

Carry out the test according to 7.10, irradiate with ultraviolet light for 200h, the change rate of K value before and after the vacuum glass test should not exceed 3%.

 

6.12 Climate cycle durability

Carry out the test according to 7.11. After the cyclic test, the sample is not allowed to burst, and the change rate of the K value before and after the vacuum glass test should not exceed 3%.

6.13 High temperature and high humidity durability

Carry out the test according to 7.12. After the cyclic test, the sample is not allowed to burst, and the change rate of the K value before and after the vacuum glass test should not exceed 3%.

6.14 Sound insulation performance

 

Test according to 7.13, the sound insulation performance of vacuum glass should be ≥30dB.

7 Test method

7.1 Thickness measurement

Take the product as a sample, use an external micrometer that meets the requirements of GB/T1216 or an instrument with the same accuracy, and measure at the midpoint of the four sides within 15mm from the edge of the glass plate. The arithmetic average of the measurement results is the thickness value and rounded to one decimal place in accordance with GB/T8170.

7.2 Measurement of size and allowable deviation

Take the product as the sample and measure it with a steel tape or steel ruler with a minimum graduation of 1 mm.

7.3 Edge processing quality

Take products as samples. Under good natural light and scattered light conditions, perform a visual inspection at a distance of about 600 mm from the front of the sample.

7.4 Cap

Same as 7.3 test method.

7.5 Support

Same as 7.3 test method.

7.6 Appearance quality

Take products as samples. Under good natural light and scattered light conditions, perform a visual inspection at a distance of about 600 mm from the front of the sample. The size of the defect is measured with a steel ruler with a minimum graduation of 0.5 mm or a reading microscope.

7.7 Edge banding quality

Take products as samples. Under good natural light and scattered light conditions, perform a visual inspection at a distance of about 600 mm from the front of the sample. The effective sealing width is measured with a steel ruler or caliper with a minimum scale of 0.5mm. The measurement distance starts from the outer edge of the vacuum glass to the end of the sealing edge inside the vacuum glass.

 

In the figure: W-effective edge banding width, in millimeters

Figure 1 Schematic diagram of effective edge sealing measurement of vacuum glass

7.8 Measurement of bow curvature

Place the sample at room temperature for more than 4 hours. When measuring, place the sample upright and place 2 pads on the 1/4 below the long side. Use a metal wire to close the two sides of the product horizontally or diagonally, measure the gap between the straight edge and the glass with a JB/T7979 feeler gauge, and use the percentage of the ratio of the height of the arc to the length of the string to express the bow shape. The degree of curvature is shown in Figure 2 and Figure 3.

 

In the figure: h — bow deformation;

w — The length or diagonal length of the vacuum glass.

Figure 2 Schematic diagram of bow deformation of vacuum glass

 

In the figure: 1 — length or width;

2 — one-half of the length or width;

3 — a quarter of the length or width;

4 — Maximum 100mm

Figure 3 Schematic diagram of support during bending measurement

7.9 Insulation performance of vacuum glass

The sample is a 1000mmX1000mm flat vacuum glass sample prepared under the same material, thickness and process conditions as the product.

The insulation performance of vacuum glass is measured in accordance with GB/T8484.

The insulation performance of vacuum glass can also be measured in accordance with the method in Appendix A of this standard.

When performing type test or arbitration test, GB/T8484 should be used for measurement.

7.10 Radiation resistance

7.10.1 The samples are two 510mmX360mm flat vacuum glass samples prepared under the same material, thickness and process conditions as the product.

7.10.2 Perform the test in accordance with the requirements of Article 6.5 of GB/T11944-2002, and measure the K value of each sample before and after irradiation. The change rate of the K value of the vacuum glass is the percentage of the absolute value of the difference between the K value before and after the irradiation and the K value of the vacuum glass before the irradiation.

7.10.3 After the test, the two specimens should all meet the requirements to be qualified. If one fails, another two spare samples can be re-tested, and both samples meet the requirements as qualified.

 

7.11 Climate cycle durability

7.11.1 The samples are two 510mmX360mm flat vacuum glass samples prepared under the same material, thickness and process conditions as the product.

7.11.2 Perform the test according to the requirements of Article 6.6 of GB/T11944-2002, and measure the K value of the vacuum glass before and after the cycle of each sample. The change rate of the K value of the vacuum glass is the percentage of the absolute value of the difference between the K value before and after the cycle and the K value of the vacuum glass before the irradiation.

7.11.3 After the test, the two samples should all meet the requirements to be qualified.

 

7.12 High temperature and high humidity durability

7.12.1 The samples are two 510mmX360mm flat vacuum glass samples prepared under the same material, thickness and process conditions as the product.

7.12.2 Perform the test according to the requirements of Article 6.6 of GB/T11944-2002, and measure the K value of the vacuum glass before and after the cycle of each sample. The change rate of the K value of the vacuum glass is the percentage of the absolute value of the difference between the K value before and after the cycle and the K value of the vacuum glass before the irradiation.

7.12.3 After the test, the two samples should all meet the requirements to be qualified.

7.13 Sound insulation performance

The sample is a 1000mmX1000mm flat vacuum glass sample prepared under the same material, thickness and process conditions as the product.

The sound insulation performance of vacuum glass is measured in accordance with GB/T8485.

8 Inspection rules

8.1 Inspection classification

Inspection is divided into factory inspection and type inspection.

8.1.1 Factory inspection

The inspection items are thickness, size, support, appearance quality, edge sealing quality, bending degree, heat preservation performance (K value).

8.1.2 Type inspection

The inspection items are all the technical requirements stipulated in this standard. In one of the following situations, type inspection shall be carried out.

— Trial type identification of new products or old products transferred to factory production.

— After trial production, if there are major changes in structure, materials, and processes, which may affect product performance.

— When normal production has reached 2 years.

— When the product has been discontinued for more than half a year and production is resumed.

— When there is a big difference between the factory inspection result and the last type.

— When the quality supervision department requests for type inspection.

8.2 Batching and sampling

8.2.1 Group batch

The vacuum glass products produced under the same process conditions with the same original material should form a batch.

8.2.2 Sampling

8.2.2.1 The factory inspection shall be randomly sampled according to Table 8.

Table 8 The unit of sampling table is block

Lot range sampling number qualified judgment number unqualified judgment number

≤50 5 0 1

50~150 10 1 2

>150 15 2 3

8.2.2.2 For the technical requirements of the product, if the product is used for inspection, sampling shall be carried out according to the factory inspection sampling rules, and randomly selected from the batch of products according to the quantity required by the inspection item; if the sample is used for the inspection, the product shall be Samples prepared under the same material, the same thickness and the same process conditions.

8.3 Judgment rules

If any of the unqualified number of thickness, size, support, appearance quality, edge sealing quality, curvature, and thermal insulation performance (K value) is greater than or equal to the unqualified number in Table 8, the product is considered to be the inspection item Unqualified.

Other properties should meet the requirements of the corresponding clauses, otherwise, the item is deemed unqualified.

If one of the above items is unqualified, the batch of products is deemed unqualified.

9 Marking, packaging, transportation and storage

9.1 Packaging

Products should be packed in containers or wooden boxes. Each piece of glass should be packed in plastic bags or paper, and the space between the glass and the packaging box should be filled with light and soft materials that are not easy to cause glass scratches and other appearance defects.

Light and soft materials should be used to protect the caps.

9.2 Packaging mark

The packaging mark should comply with the relevant national standards, including thickness, factory name, factory address, trademark, specification, quantity, production date, batch number, implementation standard, and should be marked with "face up, handle with care, be careful of broken, rainproof "Afraid of getting wet" and other words.

9.3 Transportation

During transportation, the product should be placed vertically, the length direction should be the same as the direction of the vehicle's movement, and rain-proof measures should be taken.

9.4 Storage

The product should be stored upright in a dry room.

 

Appendix A

(Informative appendix)

Measuring method of insulation performance of vacuum glass

A.1 Test principle

This method directly measures the thermal conductivity of the central part of the vacuum glass, and then calculates the K value of the insulation performance of the vacuum glass through a formula.

The thermal conductivity of vacuum glass is the sum of radiant thermal conductivity, support thermal conductivity and residual gas thermal conductivity. For qualified vacuum glass products, the residual gas thermal conductivity should be negligible.

The measurement of the thermal conductivity of vacuum glass adopts the principle of heat flow method, and the measurement of its thermal conductivity value adopts the vacuum glass thermal conductivity meter. Choose a square high thermal conductivity metal material as the measuring head, its area is equal to the square area enclosed by four adjacent supports, and the temperature at each point of the measuring head can be regarded as uniform. The measurement principle is shown in Figure A1.

 

Figure A1 Thermal conductivity meter measurement principle diagram

The upper surface of the measuring head is close to the vacuum glass sample, the lower surface is close to a standard plate with a known thermal conductivity of C mark, and underneath is a metal plate with a heating temperature controller (called a hot plate), whose temperature is controlled Hot in T. On the other side of the vacuum glass sample is a metal plate with a refrigerator (called cold plate), whose temperature is controlled at T cold. T measurement is higher than T cold, so the heat flow upwards from the hot plate, passes through the standard plate, the measuring head passes through the sample to be tested, and finally the heat flow reaches the cold plate.

After the thermal equilibrium, the heat flow is constant, and the temperature of the measuring head is stable at T measurement. Since the components on the heat flow channel are connected in series, their temperature drop is proportional to their thermal resistance and inversely proportional to the thermal conductivity. The temperature difference on the sample is reduced to (T test-T cold), and the temperature difference of the standard plate is reduced to (T hot-T test). Thus:

C test=(T heat-T test) C standard/(T test-T cold)……………………(1)

in

C is measured as the thermal conductivity measurement value of vacuum glass, the unit is W/(m2•K)

C is the thermal conductivity value of the standard board, the unit is W/(m2•K)

T heat is the temperature of the hot plate in K

T is measured as the temperature of the measuring head in K

T cold is the temperature of the cold plate in K

 

A.2 Test conditions

Ambient temperature: 22℃±2℃, relative humidity: 20%~75%.

A.3 Sample

The sample is a 1000mmX1000mm sample prepared under the same material, the same thickness, and the same process conditions as the product.

A.4 Test device

The thermal conductivity meter is divided into two units and placed on both sides of the tested sample. (See Figure A2)

 

Figure A2 Thermal conductivity meter structure diagram

The top of the vacuum glass sample 2 is the cold plate 1, which is composed of a 150mm×150mm aluminum plate or other high thermal conductivity material and a cooler, and its temperature should be kept at T cold.

The hot plate 5 is also made of aluminum plate or other high thermal conductivity materials, with an area of ​​150mm×150mm, with a heating device inside, and its temperature should be kept at T heat. The measuring board 3 is composed of the measuring head and its outer isolating ring, and its top view is shown in Figure A3. Its total area is also 150mm×150mm, and the measuring head is square.

 

Figure A3 The top view of the measuring board

The area shown by the dashed line in Figure A3 is the effective area for measurement. Its shape is square, and the side length is the distance between the supports in the vacuum glass. If you are measuring vacuum glass samples with different distances between supports, you only need to replace the measuring board with the corresponding effective area.

The effective area of ​​measurement is equal to the square area formed by four adjacent supports. Multiple concentric buffer isolation rings are arranged around the measuring head, with air gaps between them to avoid external influence on the measuring head and make the T measurement stable. The measuring head and isolating ring are made of high thermal conductivity material copper or aluminum. The measurement error of the instrument should be within ±5%.

 

A.5 Test procedure

A.5.1 Thermal conductivity measurement of vacuum glass, C measurement

A.5.1.1 First put the vacuum glass thermal conductivity measurement board above the standard board, and then put the vacuum glass sample between the cold plate and the measuring head. The distance between the measuring head and the edge of the sample should be greater than 50mm.

A.5.1.2 Set the temperature of the cold plate to 10°C and the temperature of the hot plate to 40°C, and heat the measuring head to reach the specified value. The temperature of the cold plate, hot plate and measuring head should be stable within ±0.01°C.

A.5.1.3 After the instrument is stable, record the thermal conductivity indication value of the instrument at this time, namely the C measurement and the temperature T measurement of the measuring head.

 

A.5.2 Measurement of radiant thermal conductivity of vacuum glass, C radiation

A.5.2.1 Replace the vacuum glass thermal conductivity measurement board with a vacuum glass radiant thermal conductivity measurement board, and repeat the steps in A5.1.1 and A.5.1.2.

A.5.2.2 After the instrument is stable, record the thermal conductivity indication value of the instrument at this time, that is, C radiation.

 

A.5.3 Data processing

A.5.3.1 Correction of actual measured value

The actual measured value of the thermal conductivity of the vacuum glass should be corrected according to formula (2) to obtain the corrected thermal conductivity value of the vacuum glass Cˊ

Cˊmeasure=(Cmeasure-C radiation)+C radiation(272/[(Tmeasure+Tcool)/2+273])3 …………………………..(2)

 

C is measured as the thermal conductivity measurement value of vacuum glass, the unit is W/(m2•K)

C radiation is the measured value of the radiant thermal conductivity of vacuum glass, the unit is W/(m2•K)

Cˊ is measured as the corrected thermal conductivity of vacuum glass, the unit is W/(m2•K)

T is measured as the temperature of the measuring head, the unit is ℃

T cold is the temperature of the cold plate, the unit is ℃

Note: Cˊ measurement should be rounded to two decimal places according to GB/T8170.

 

A.5.4 Conversion formula between K value and vacuum glass thermal conductivity

 

K=1/(1/8.7+1/Cˊmeasure+1/23) ………………………….. (3)

K heat transfer coefficient value of vacuum glass, the unit is W/(m2•K);

Cˊ is measured as the thermal conductivity value of vacuum glass, the unit is W/(m2•K);

Note: K value should be rounded to two decimal places according to GB/T8170.

Appendix B

(Informative appendix)

Vacuum glass structure diagram

Figure B1 Structure diagram of vacuum glass

In the picture:

1- glass;

2- support;

3- Edge banding;

4- cap

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