A method and device for measuring fire resistance of gypsum board

Abstract

The invention discloses a method and device for measuring the fire resistance of a gypsum board. The method comprises the following steps: arranging a mounting bracket at one end of a support to fix one end of the gypsum board, setting a load at the other end of a specimen, setting a limiting surface on the support below the load, setting a burner on the side of the specimen, connecting the burner to the support, and providing a temperature sensor between the burner and the specimen. The method comprises the following steps: constructing a corresponding relationship among the inherent properties of the specimen material, the distance from the specimen where the load is set to a combustion damage surface, the load drop height, and the load weight, deploying the combustion surface position and the limiting surface setting height based on the corresponding relationship, selecting the load weight, burning the combustion surface, setting the combustion test time based on the fire escape time, and determining whether the combustion performance of the gypsum board meets the engineering use requirements by determining whether the specimen crosses the limiting surface within the combustion test time or whether the specimen destruction time exceeds the combustion test time.

Description

Technical Field

[0001] The invention relates to the technical field of building material detection, and in particular to a method and a device for measuring the fire resistance of a gypsum board. Background Art

[0002] Gypsum board is a board made of building gypsum as the main raw material, with appropriate additives and fibers as the board core, and special paperboard as the surface. Due to its light weight, good heat insulation and sound insulation, and simple construction method, gypsum board has been widely used in the field of construction engineering. At present, gypsum board in decoration and renovation projects is mainly built with light steel keels to form gypsum board-keel partition / ceiling system. The application rate of this application method in my country's interior decoration projects has increased year by year, and the annual increase has exceeded 10% in the past ten years. Such a high application rate is bound to put forward higher requirements for materials from the perspective of fire retardancy. In the early stage of application, gypsum board was rarely used in partition systems, mainly in ceiling systems, but with the gradual increase in the requirements of my country's decoration and renovation projects for easy installation, light materials, and green environmental protection, the application of gypsum board in partition systems has become more and more widespread.

[0003] In the prior art, the combustion performance and fire resistance limit, which are indicators for measuring the fire retardancy of materials, are mostly tested on assembled systems. Although it is feasible and practical to test the combustion performance of gypsum board alone, the test method is relatively complicated and has very high requirements for the test environment, equipment, personnel, safety, etc. It can only be used for professional laboratory testing. For a large number of engineering site material acceptance, it still only remains on paper materials and lacks actual testing and acceptance.

[0004] In the national standard GB / T 9775 for gypsum board, the test for fire stability is to use a support rod to hang the specimen vertically between two flame nozzles, with the flame nozzles perpendicular to the surface of the specimen, hang a load at the lower end of the specimen, ignite the burner, measure the temperature through a thermocouple, maintain a certain temperature during the test, start timing from the specimen encountering fire to the specimen breaking and damaging, record the time when each specimen is burned, and take the minimum value among the five specimens as the fire stability of the group of specimens. Although this method can measure the fire resistance to a certain extent, the testing principle of this method is based on the stress damage of the gypsum board when the ceiling system encounters fire, that is, the rectangular specimen is placed vertically and the load is placed at the bottom, and the burning surface breaks and falls off due to combustion and gravity. In fact, it cannot measure the fire resistance of the gypsum board in the partition system, that is, the rectangular specimen needs to be placed horizontally and upright, and the burning surface is deformed, bent or broken due to combustion and gravity. Summary of the invention

[0005] In order to solve the shortcomings of the prior art and achieve the purpose of quickly, effectively and simply determining the fire resistance of gypsum board in the partition system, the present invention adopts the following technical solution:

[0006] A method for measuring the fire resistance of gypsum board comprises the following steps:

[0007] Step S1, obtaining a gypsum board specimen; cutting one or more gypsum boards of a fixed size for measurement from the entire gypsum board;

[0008] Step S2, constructing a combustion device;

[0009] Step S3, fix one end of the specimen, set a load on the other end, set a restriction surface under the load, select a combustion surface between the two ends of the specimen, construct a correspondence between the inherent properties of the specimen material, the distance from the specimen where the load is set to the combustion damage surface, the load drop height, and the load weight, deploy the combustion surface position, restriction surface height, and load weight based on the correspondence, and burn the combustion surface;

[0010] Step S4: Based on the fire escape time, the combustion test time is set, and whether the combustion performance of the gypsum board meets the engineering use requirements is determined by whether the specimen crosses the restricted surface during the combustion test time, or whether the time for the specimen to be destroyed exceeds the combustion test time.

[0011] Furthermore, the corresponding relationship in step S3 is as follows:

[0012]

[0013] Where m represents the mass of the load, It represents the angle of shear deformation of the specimen due to combustion, E represents Young's modulus, I represents the moment of inertia, v represents Poisson's ratio, E, v, and I are inherent properties of the material, g represents the acceleration of gravity, L0 represents the distance from the load hanging on the gypsum board to the combustion damage surface, and h represents the load drop height. The limit surface height is set based on h.

[0014] Furthermore, in step S3, a bending moment M is applied to the specimen based on the combustion of the combustion surface and gravity, and an angle θ of shear deformation of the specimen due to combustion is obtained to obtain the load mass m required to be set;

[0015]

[0016] Here, g represents the acceleration due to gravity.

[0017] Furthermore, the combustion test time in step S4 is between 6 and 18 minutes.

[0018] A device for measuring the fire resistance of a gypsum board comprises a support, a mounting bracket, a burner, a temperature sensor, a restriction surface and a load, wherein one end of the support is provided with a mounting bracket for fixing one end of the gypsum board as a specimen, the load is set at the other end of the specimen, a restriction surface is provided on the support below the load, a burner is provided on the side of the specimen, the burner is connected to the support, and a temperature sensor is provided between the burner and the specimen; a correspondence between the inherent properties of the specimen material, the distance from the specimen where the load is set to the combustion damage surface, the load drop height, and the load weight is constructed, and based on the corresponding relationship, the combustion surface position, the restriction surface height, and the load weight are deployed to burn the combustion surface.

[0019] Furthermore, the corresponding relationship is as follows:

[0020]

[0021] in, It represents the angle of shear deformation of the specimen due to combustion, E represents Young's modulus, I represents the moment of inertia, v represents Poisson's ratio, E, v, and I are inherent properties of the material, g represents the acceleration of gravity, L0 represents the distance from the load hanging on the gypsum board to the combustion damage surface, and h represents the load drop height. The limit surface height is set based on h.

[0022] Furthermore, based on the bending moment M exerted on the specimen by the combustion of the combustion surface and gravity, and the angle θ of the shear deformation of the specimen due to the combustion, the load mass m required to be set is obtained;

[0023]

[0024] Here, g represents the acceleration due to gravity.

[0025] Furthermore, the mounting bracket is provided with an open inner cavity cooperating with one end of the specimen, a through hole with a positioning pin is provided on one side of the open inner cavity, the specimen is a laterally fixed rectangle, one end of the specimen is inserted into the opening of the inner cavity, and the positioning pin on the side of the inner cavity fixes the surface side of one end of the specimen through the through hole.

[0026] Furthermore, a pair of burners were symmetrically arranged on both sides of the time, with the lowest point of the burner nozzle and the lower end of the long side of the specimen on the same horizontal plane, for baseline calibration.

[0027] Furthermore, the device also includes a gas source, a pressure reducing valve and a pressure gauge, a flow meter, and a Y-type connector connected in sequence, the two output ends of the Y-type connector are respectively connected to a pair of burners, and a pressure control valve is provided between the output end of the Y-type connector and the burner.

[0028] The advantages and beneficial effects of the present invention are:

[0029] The present invention greatly reduces the requirements for test environment, equipment, personnel, safety and other conditions in traditional tests. Traditional fire resistance performance tests, such as combustion performance and fire resistance limit, need to be carried out in professional large laboratories, and the equipment is bulky and cannot be moved. The present invention can be used for testing at construction sites with complex environments, and the equipment is compact and portable. Secondly, traditional testing methods have very high requirements for operators, who need professional training and a lot of experience to accurately measure. The present invention reduces the requirements for personnel quality, and only requires simple training, and the ability to use a steel ruler to measure distance and a switch pressure valve to control gas flow can be used for operation. Thirdly, The test process of the traditional method generates a large amount of heat and exhaust gas, and the job safety requirements are high. In addition, the large amount of high-heat exhaust gas discharged seriously pollutes the environment. The amount of gas used in the test of the present invention is small, the flame is small, the safety level is very high, and the process only generates a small amount of heat, which greatly reduces environmental emissions. Finally, the acceptance of the paper-faced gypsum board in the traditional project can only accept the appearance size, and the acceptance of the fire resistance can only be done by accepting the test report. When the test report and the actual production batch of the incoming materials are inconsistent, it is difficult to verify. The present invention can be directly tested on the construction site, and the test results are highly consistent with the laboratory results. The present invention provides an accurate acceptance basis for the acceptance of engineering materials in practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a flow chart of a method in an embodiment of the present invention.

[0031] Figure 2a It is one of the schematic diagrams of various elements for constructing a corresponding relationship in an embodiment of the present invention.

[0032] Figure 2b This is the second schematic diagram of the elements for constructing a corresponding relationship in an embodiment of the present invention.

[0033] Figure 3 Schematic diagram of the test piece installation structure of the device in the embodiment of the present invention.

[0034] Figure 4 It is a schematic diagram of the top view of the test piece installation structure of the device in an embodiment of the present invention.

[0035] Figure 5 Schematic diagram of the structure of the baseline calibration in the embodiment of the present invention.

[0036] In the figure: 1. test piece, 2. load, 3. restriction surface, 4. support, 5. mounting bracket, 6. through hole, 7. burner, 8. positioning pin, 9. temperature sensor. DETAILED DESCRIPTION

[0037] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0038] like Figure 1 As shown, a method for measuring the fire resistance of gypsum board is provided. The principle is as follows: a stress model of a gypsum board specimen 1 (hereinafter referred to as specimen 1) is simulated according to the actual construction and installation conditions of the gypsum board; a bending moment is applied to the specimen 1 when a pair of burners 7 heat the specimen 1; the bending moment causes the specimen 1 to deform during heating, and when the specimen 1 is completely deformed, the specimen 1 breaks; by measuring whether the specimen 1 is damaged and the degree of deformation within a certain heating time, the core material cohesion of the specimen 1 at high temperature is measured, and then the combustion performance of the specimen 1 is qualitatively determined. The method specifically includes the following steps:

[0039] Step S1, sample preparation: obtaining a gypsum board; cutting one or more gypsum boards of a fixed size for measurement from the whole gypsum board (hereinafter referred to as specimen 1);

[0040] In the embodiment of the present invention, the thickness of the test piece 1 is 12 mm, the size is 300 mm*(45-50) mm, and the long side is parallel to the edge of the gypsum board, which is consistent with the size of the fire stability test piece in the GB / T 9775-2008 standard. This is to ensure that the test results are consistent with the experimental results of the national standard to a certain extent.

[0041] Step S2, constructing a combustion device: The combustion device is composed of multiple components, including a support 4, a pair of Fisher burners 7 (Meker-Fisher Burner), a thermocouple, a mounting bracket 5, a propane gas source, a pressure reducing valve and a pressure gauge, a flow meter, a Y-type connector, and a pressure control valve. The components except the support 4 are installed and integrated on the support 4 by welding or clamping to form the combustion device;

[0042] In the embodiment of the present invention, the nozzle diameter of the Fisher burner 7 is (29-30) mm, the gas nozzle diameter is (0.7-0.8) mm, and the position on the support 4 is adjustable; the thermocouple is a K-type armored insulated nickel-chromium-nickel-aluminum (nickel-silicon) thermocouple, which has a wide operating temperature range, stable performance at high temperatures, and is suitable for continuous use in oxidizing and inert atmospheres. The short-term operating temperature is 1200°C and the long-term operating temperature is 1000°C. The relationship between the thermoelectric potential and the temperature is approximately linear, and the price is low. The thermocouple is fixed on the Fisher burner 7. , and its position is 10mm away from the nozzle of the Fisher burner 7; the mounting bracket 5 is made of steel and welded on the support 4. The inner cavity size of the mounting bracket 5 is (12-25)mm wide*300mm high*25mm deep. A positioning pin 8 is provided on one side to fix one end of the test piece 1 on the inner cavity of the mounting bracket 5; the propane gas source supplies propane gas to each Fisher burner 7 through a Y-type connector; a pressure reducing valve, a press, and a flow meter are installed in sequence between the propane gas source and the Y-type connector; the pressure control valve is installed on the gas supply pipeline at the rear end of the Y-type connector.

[0043] Step S3, combustion test: fix one end of the specimen 1, set a load 2 at the other end, set a restriction surface 3 below the load 2, select a combustion surface between the two ends of the specimen 1, establish a correspondence between the material properties of the specimen, the distance from the specimen 1 where the load 2 is set to the combustion damage surface, the load weight, and the height of the restriction surface, and set the test conditions based on the correspondence to perform the combustion test;

[0044] Test principle: When the gypsum core is exposed to a high temperature of 1000°C, it loses water quickly and changes from CaSO4·1 / 2H2O to AⅢ-CaSO4, losing its strength (interlayer strength). At this time, only the gypsum core on the failure surface provides the shear resistance of specimen 1.

[0045] like Figure 2a , Figure 2b As shown, the bending moment at the failure surface at the end is:

[0046] M=θ·GI / L=F·L0 / 2 (1)

[0047] Among them, θ represents the angle that load 2 rotates from point a to point b, that is, the angle of shear deformation, L0 represents the lever arm, which is the straight-line distance from load 2 hanging on the gypsum board to the failure surface, L represents the distance from load 2 at point b to point o on the failure surface, G represents the shear modulus, I represents the moment of inertia, which is the basic property of the material (constant) and can be obtained by looking up the table or measuring with a rotating G meter, and F represents the force of load 2 acting perpendicular to L0 at point o.

[0048] For the force F, according to trigonometric functions, △oab is an isosceles triangle, and the vertical distance h from point a to point b is the total stroke from the initial position of load 2 to the end of the test, that is, the height of the load 2 drop, then therefore:

[0049]

[0050] Here, g represents the acceleration due to gravity.

[0051] For the shear modulus G, G=E / 2(1+v), E represents Young's modulus, which can be measured by a laboratory tensile test based on the burning surface diameter d and the specimen thickness e, and v represents Poisson's ratio, which can be measured by a laboratory bending test. E and v are generally empirical values.

[0052] According to formula (1) and (2), we get:

[0053]

[0054] By deducing formula (3), we get the corresponding relationship:

[0055]

[0056] Among them, E, v, and I are inherent properties of the material and do not change with the paper version, so empirical values ​​can be used.

[0057] In another embodiment, when E, v, and I are inconvenient to obtain, a bending moment M can be applied to the specimen 1 based on the combustion of the combustion surface for measurement, and the required load mass m can be obtained through the bending moment M and the angle θ of the shear deformation of the specimen 1 due to the combustion;

[0058]

[0059] Here, g represents the acceleration due to gravity.

[0060] In the embodiment of the present invention, the exposed part of the test piece 1 after being fixed on the mounting bracket 5 is taken as the support point, and the positioning pin 8 is tightened to fix the test piece 1 on the mounting bracket 5 of the combustion device; a load 2 is suspended at 260mm from the support point according to the thickness of the test piece 1 of 300g, and the load 2 can be a component such as a scale weight, and its weight is (300-600)g adjustable; a limiting surface 3 is set at 10mm from the lower end of the load 2, which can be a stack of bricks, and the highest point of the brick is 10mm away from the lower end surface of the load 2, according to the load during the test. 2 The termination of the test is determined by whether the lower surface of the specimen 1 bends due to heat and crosses the limiting surface 3; the baseline must be calibrated before adjusting the position of the burner 7 nozzle, so that a pair of burner 7 nozzles are respectively set on the two sides of the specimen 1, and the lowest point of the burner 7 nozzle is on the same horizontal plane as the lower end of the long side of the specimen 1. The three-dimensional position of the burner 7 nozzle is adjusted so that the center point of the nozzle is 100mm away from the support point and the nozzle is 25mm away from the specimen. The burner 7 is ignited, the propane flow is adjusted so that the thermocouple temperature reading is (950-1050)℃, and the specimen 1 is burned for testing.

[0061] Step S4, result analysis: Based on the fire escape time, the combustion test time is set, and whether the combustion performance of the gypsum board meets the requirements for general decoration and renovation projects is determined by whether the specimen 1 crosses the restriction surface 3 during the combustion test time or whether the time for the specimen 1 to be destroyed exceeds the combustion test time.

[0062] In the embodiment of the present invention, whether the lower end of the load 2 contacts the brick surface within 15 minutes is used as the termination condition. When the lower end of the load 2 touches the brick surface within 15 minutes, the test result is that the core material has poor high-temperature cohesion, and the test piece 1 is considered to be damaged and the fire resistance performance is unqualified; when the lower end of the load 2 does not cross the restriction surface 3 for more than 15 minutes, the test can be terminated, and the test piece 1 is considered to be undamaged and the fire resistance performance is qualified. When a fire accident occurs, the best escape time for personnel is 90 seconds, 2 to 3 minutes for residential buildings, and 5 to 6 minutes for high-rise buildings. According to the corresponding fire acceptance specifications, it is reasonable to use 3 times the escape time as the test termination time.

[0063] like Figure 3 , Figure 4 As shown, a device for measuring the fire resistance of gypsum board comprises a support 4, a mounting bracket 5, a burner 7, a temperature sensor 9, a limiting surface 3 and a load 2, characterized in that: a mounting bracket 5 is provided at one end of the support 4 for fixing one end of the gypsum board as a specimen 1, the load 2 is arranged at the other end of the specimen 1, a limiting surface 3 is provided on the support 4 below the load 2, a burner 7 is provided on the side of the specimen 1, the burner 7 is connected to the support 4, and a temperature sensor 9 is provided between the burner 7 and the specimen 1; the correspondence between the inherent properties of the specimen material, the distance from the specimen 1 where the load 2 is set to the combustion damage surface, the descending height of the load 2, and the load weight is constructed, and based on the corresponding relationship, the combustion surface position, the limiting surface setting height, and the load weight are deployed to burn the combustion surface.

[0064] The corresponding relationship is as follows:

[0065]

[0066] in, It represents the angle of shear deformation of specimen 1 due to combustion, E represents Young's modulus, I represents the moment of inertia, v represents Poisson's ratio, E, v, and I are inherent properties of the material, g represents the acceleration of gravity, L0 represents the distance from the load 2 hanging on the gypsum board to the combustion damage surface, h represents the descending height of load 2, and the limit surface height is set based on h.

[0067] In another embodiment, when E, v, and I are inconvenient to obtain, the required load mass m can be obtained based on the bending moment M exerted on the specimen 1 by the combustion and gravity of the combustion surface, and the angle θ of the shear deformation of the specimen 1 due to the combustion;

[0068]

[0069] Here, g represents the acceleration due to gravity.

[0070] The mounting bracket 5 is provided with an open inner cavity matching with one end of the specimen 1, and a through hole 6 with a positioning pin 8 is provided on one side of the open inner cavity. The specimen 1 is a laterally fixed rectangle, and one end of the specimen 1 is inserted into the opening of the inner cavity. The positioning pin 8 on the side of the inner cavity passes through the through hole 6 to fix the surface side of one end of the specimen 1.

[0071] like Figure 5 As shown, a pair of burners 7 are symmetrically arranged on both sides of the time, and the lowest point of the burner 7 nozzle is on the same horizontal plane as the lower end of the long side of the test piece 1, and a baseline calibration is performed.

[0072] The device also includes a gas source, a pressure reducing valve and a pressure gauge, a flow meter, and a Y-type connector connected in sequence. The two output ends of the Y-type connector are respectively connected to a pair of burners 7. A pressure control valve is provided between the output end of the Y-type connector and the burner 7.

[0073] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for measuring the fire resistance of gypsum board, characterized in that The steps include: Step S1, obtaining a gypsum board specimen (1); Step S2, constructing a combustion device; Step S3, fix one end of the specimen (1), set a load (2) at the other end, set a restriction surface (3) below the load (2), select a combustion surface between the two ends of the specimen (1), construct a corresponding relationship between the inherent properties of the specimen material, the distance from the specimen (1) where the load (2) is set to the combustion damage surface, the height of the load (2), and the load weight, deploy the combustion surface position, the restriction surface height, and the load weight based on the corresponding relationship, and burn the combustion surface; the corresponding relationship is as follows: Where m represents the mass of the load, represents the angle of shear deformation of the specimen (1) due to combustion, E represents Young's modulus, I represents the moment of inertia, v represents Poisson's ratio, E, v, and I are inherent properties of the material, g represents the acceleration of gravity, L0 represents the distance from the load (2) hanging on the gypsum board to the combustion damage surface, h represents the drop height of the load (2), and the height of the limit surface is set based on h; Step S4: Based on the fire escape time, a combustion test time is set, and whether the combustion performance of the gypsum board meets the engineering use requirements is determined by whether the test piece (1) crosses the restriction surface (3) within the combustion test time, or whether the time of destruction of the test piece (1) exceeds the combustion test time.

2. A method for measuring fire resistance of gypsum board according to claim 1, characterized in that: In step S3, the bending moment at the failure surface is: M=θ·GI / L=F·L0 / 2 Wherein, θ represents the angle from the point where the load (2) is located before the failure to the point where the load (2) is located after the failure, that is, the angle of shear deformation, L0 represents the lever arm, which is the straight-line distance from the load (2) hanging on the gypsum board to the failure surface, L represents the distance from the point where the load (2) is located after the failure to the failure surface, G represents the shear modulus, I represents the moment of inertia, and F represents the force of the load (2) acting perpendicular to L0 at the failure point; For the force F, the vertical distance h from the point where the load (2) is located before the failure to the point where the load (2) is located after the failure is the total stroke from the initial position of the load (2) to the end of the test, that is, the height of the load (2) falling, then therefore: A bending moment M is applied to the specimen (1) based on the combustion of the combustion surface and gravity, and an angle θ of shear deformation of the specimen (1) due to the combustion is obtained to obtain a load mass m required to be set; Here, g represents the acceleration due to gravity.

3. A method for measuring fire resistance of gypsum board according to claim 1, characterized in that: The combustion test time in step S4 is between 6 and 18 minutes.

4. A device for measuring the fire resistance of a gypsum board, comprising a support (4), a mounting bracket (5), a burner (7), a temperature sensor (9), a limiting surface (3) and a load (2), characterized in that: A mounting bracket (5) is provided at one end of the support (4) for fixing one end of a gypsum board as a test piece (1); a load (2) is provided at the other end of the test piece (1); a limiting surface (3) is provided on the support (4) below the load (2); a burner (7) is provided on the side of the test piece (1); the burner (7) is connected to the support (4); a temperature sensor (9) is provided between the burner (7) and the test piece (1); a correspondence is established between the inherent properties of the test piece material, the distance from the place where the load (2) is provided on the test piece (1) to the combustion damage surface, the height of the load (2) and the load weight; based on the corresponding relationship, the combustion surface position, the limiting surface height and the load weight are arranged to burn the combustion surface; The corresponding relationship is as follows: in, represents the angle of shear deformation of the specimen (1) due to combustion, E represents Young's modulus, I represents the moment of inertia, v represents Poisson's ratio, E, v, and I are inherent properties of the material, g represents the gravitational acceleration, L0 represents the distance from the load (2) suspended on the gypsum board to the combustion damage surface, h represents the drop height of the load (2), and the limit surface height is set based on h.

5. A device for measuring fire resistance of gypsum board according to claim 4, characterized in that: Bending moment at failure surface: M=θ·GI / L=F·L0 / 2 Wherein, θ represents the angle from the point where the load (2) is located before the failure to the point where the load (2) is located after the failure, that is, the angle of shear deformation, L0 represents the lever arm, which is the straight-line distance from the load (2) hanging on the gypsum board to the failure surface, L represents the distance from the point where the load (2) is located after the failure to the failure surface, G represents the shear modulus, I represents the moment of inertia, and F represents the force of the load (2) acting perpendicular to L0 at the failure point; For the force F, the vertical distance h from the point where the load (2) is located before the failure to the point where the load (2) is located after the failure is the total stroke from the initial position of the load (2) to the end of the test, that is, the height of the load (2) falling, then therefore: Based on the bending moment M exerted on the specimen (1) by the combustion of the combustion surface and gravity, and the angle θ of the shear deformation of the specimen (1) due to the combustion, the load mass m required to be set is obtained; Here, g represents the acceleration due to gravity.

6. A device for measuring fire resistance of gypsum board according to claim 4, characterized in that: The mounting bracket (5) is provided with an open inner cavity matched with one end of the test piece (1), and a through hole (6) with a positioning pin (8) is provided on one side of the open inner cavity.

7. The device for measuring fire resistance of gypsum board according to claim 4, characterized in that: A pair of burners (7) are symmetrically arranged on both sides of the test piece, and the lowest point of the burner (7) nozzle is on the same horizontal plane as the lower end of the long side of the test piece (1).

8. The device for measuring fire resistance of gypsum board according to claim 4, characterized in that: The device also includes a gas source, a pressure reducing valve and a pressure gauge, a flow meter, and a Y-type connector which are connected in sequence. The two output ends of the Y-type connector are respectively connected to a pair of burners (7). A pressure control valve is provided between the output end of the Y-type connector and the burner (7).

Images