GOST 30247.0-94 (ISO 834-75)
INTERSTATE STANDARD
BUILDING STRUCTURES
FIRE RESISTANCE TEST METHODS
GENERAL REQUIREMENTS
Official publication
INTERSTATE SCIENTIFIC AND TECHNICAL COMMISSION FOR STANDARDIZATION AND TECHNICAL REGULATION IN CONSTRUCTION (INTKS)
Preface
1 DEVELOPED by the State Central Research and Design Experimental Institute complex problems building structures and structures named after V. A. Kucherenko (TsNIISK named after Kucherenko) of the Ministry of Construction of Russia, the Center for Fire Research and Thermal Protection in Construction TsNIISK (CPITZS TsNIISK) and the All-Russian Research Institute of Fire Defense (VNIIPO) of the Ministry of Internal Affairs of Russia
INTRODUCED by the Ministry of Construction of Russia
2 ADOPTED by the Interstate Scientific and Technical Commission for Standardization and Technical Regulation in Construction (INTKS) on November 17, 1994.
3 This standard is an authentic text of ISO 834-75 Fire resistance test. Elements of building constructions. “Fire resistance tests. Building construction"
4 ENTERED INTO EFFECT on January 1, 1996 as state standard Russian Federation Resolution of the Ministry of Construction of Russia dated March 23, 1995 No. 18-26
5 INSTEAD ST SEV 1000-78
6 REPUBLICATION. May 2003
© IPC Publishing House of Standards, 1996 © IPC Publishing House of Standards, 2003
This standard cannot be fully or partially reproduced, replicated and distributed as an official publication on the territory of the Russian Federation without permission from the Ministry of Construction of Russia
1 area of use............................................... ........ 1
3 Definitions................................................... ............. 1
4 Essence of test methods................................................................. . 1
5 Bench equipment................................................................... ..... 2
6 Temperature................................................................... ...... 3
7 Samples for testing structures.................................................... 4
8 Carrying out tests................................................... ..... 4
9 Limit states......................................................... ...... 5
10 Designations of fire resistance limits for structures.................................... 5
11 Evaluation of test results................................................................. 6
12 Test report................................................... ...... 6
Appendix A Safety requirements for testing........... 7
GOST 30247.0-94 (ISO 834-75)
INTERSTATE STANDARD
Building structures TEST METHODS FOR FIRE RESISTANCE General requirements
Elements of building constructions. Fire-resistance test methods. General requirements
Date of introduction 1996-01-01
1 AREA OF USE
This standard regulates General requirements to test methods for building structures and elements engineering systems(hereinafter referred to as structures) for fire resistance under standard conditions of thermal exposure and is used to establish fire resistance limits.
The standard is fundamental in relation to standards for fire resistance testing methods for specific types of structures.
When establishing fire resistance limits for structures in order to determine the possibility of their use in accordance with fire safety requirements regulatory documents(including during certification) the methods established by this standard should be applied.
2 REGULATORY REFERENCES
3 DEFINITIONS
The following terms are used in this standard:
3.1 fire resistance of the structure: According to GOST 12.1.033.
3.2 fire resistance limit of the structure: According to GOST 12.1.033.
3.3 limiting state of a structure for fire resistance: The state of a structure in which it loses the ability to maintain load-bearing and/or enclosing functions in fire conditions.
4 ESSENCE OF TEST METHODS
The essence of the methods is to determine the time from the beginning of thermal impact on a structure in accordance with this standard until the onset of one or successively several limit states for fire resistance, taking into account the functional purpose of the structure.
Official publication
5 STAND EQUIPMENT
5.1 Bench equipment includes:
Test furnaces with a fuel supply and combustion system (hereinafter referred to as furnaces);
Devices for installing the sample on the furnace, ensuring compliance with the conditions of its fastening and loading;
Systems for measuring and recording parameters, including equipment for filming, photography or video recording.
5.2 Furnaces
5.2.1 Furnaces must provide the ability to test structural samples under the required conditions of loading, support, temperature and pressure specified in this standard and in the standards for testing methods for specific types of structures.
5.2.2 The main dimensions of the furnace openings must be such as to ensure the possibility of testing samples of structures of designed sizes.
If it is not possible to test samples of design sizes, their dimensions and furnace openings must be such as to ensure the conditions of thermal exposure to the sample, regulated by standards for fire resistance testing methods for specific types of structures.
The depth of the furnace fire chamber must be at least 0.8 m.
5.2.3 The design of the furnace masonry, including its outer surface, must provide the possibility of installing and fastening the sample, equipment and fixtures.
5.2.4 The temperature in the furnace and its deviations during the test must comply with the requirements of section 6.
5.2.5 The temperature regime of the furnaces must be ensured by combustion liquid fuel or gas.
5.2.6 The combustion system must be adjustable.
5.2.7 The burner flame should not touch the surface of the structures being tested.
5.2.8 When testing structures whose fire resistance limit is determined by the limit states specified in 9.1.2 and 9.1.3, excess pressure must be ensured in the fire space of the furnace.
It is allowed not to control excess pressure when testing the fire resistance of load-bearing rod structures (columns, beams, trusses, etc.), as well as in cases where its influence on the fire resistance limit of the structure is insignificant (reinforced concrete, stone, etc. structures).
5.3 Test ovens load-bearing structures must be equipped with loading and supporting devices that ensure loading of the sample in accordance with its design diagram.
5.4 Requirements for measuring systems
5.4.1 During testing, the following should be measured and recorded:
Parameters of the environment in the fire chamber of the furnace - temperature and pressure (taking into account 5.2.8);
Loading and deformation parameters when testing load-bearing structures.
5.4.2 The temperature of the medium in the fire chamber of the furnace must be measured by thermoelectric converters (thermocouples) in at least five places. In this case, for every 1.5 m 2 of the opening of the furnace intended for testing enclosing structures, and for every 0.5 m of the length (or height) of the furnace intended for testing rod structures, at least one thermocouple must be installed.
The soldered end of the thermocouple should be installed at a distance of 100 mm from the surface of the calibration sample.
The distance from the soldered end of the thermocouples to the furnace walls must be at least 200 mm.
5.4.3 The temperature in the furnace is measured by thermocouples with electrodes with a diameter of 0.75 to 3.2 mm. The hot junction of the electrodes must be free. The protective casing (cylinder) of the thermocouple must be removed (cut and removed) at a length of (25+10) mm from its soldered end.
5.4.4 To measure the temperature of samples, including on the unheated surface of enclosing structures, thermocouples with electrodes with a diameter of no more than 0.75 mm are used.
The method of attaching thermocouples to the test sample of the structure must ensure an accuracy of measuring the temperature of the sample within +5%.
In addition, to determine the temperature at any point on an unheated surface,
In structures in which the greatest increase in temperature is expected, it is allowed to use a portable thermocouple equipped with a holder or other technical means.
5.4.5 The use of thermocouples with a protective casing or with electrodes of other diameters is permitted, provided that their sensitivity is not lower and the time constant is not higher than that of thermocouples made in accordance with 5.4.3 and 5.4.4.
5.4.6 To record measured temperatures, instruments of at least accuracy class 1 should be used.
5.4.7 Instruments intended for measuring pressure in a furnace and recording the results must provide a measurement accuracy of +2.0 Pa.
5.4.8 Measuring instruments must provide continuous recording or discrete recording of parameters with an interval of no more than 60 s.
5.4.9 To determine the loss of integrity of enclosing structures, use a cotton or natural wool swab.
The dimensions of the tampon should be 100x100x30 mm, weight - from 3 to 4 g. Before use, the tampon should be kept in a drying cabinet at a temperature of (105 ± 5) ° C for 24 hours. From drying cabinet The tampon is removed no earlier than 30 minutes before the start of the test. Reuse tampons are not allowed.
5.5 Calibration of bench equipment
5.5.1 Calibration of furnaces consists of control temperature regime and pressure in the furnace volume. In this case, a calibration sample is placed in the opening of the furnace for testing structures.
5.5.2 The design of the calibration sample must have a fire resistance rating no less than the calibration time.
5.5.3 The calibration sample for furnaces intended for testing enclosing structures must be made of reinforced concrete slab thickness of at least 150 mm.
5.5.4 The calibration sample for furnaces intended for testing rod structures must be made in the form reinforced concrete column with a height of at least 2.5 m and a cross-section of at least 0.04 m 2.
5.5.5 Calibration duration - at least 90 minutes.
6 TEMPERATURE CONDITION
6.1 During the testing and calibration process, a standard temperature regime must be created in furnaces, characterized by the following relationship:
T - T 0 = 345 lg (81 + 1), (1)
where T is the temperature in the furnace corresponding to time t, °C;
T 0 - temperature in the furnace before the start of thermal exposure (taken equal to the temperature environment), °С;
t - time calculated from the beginning of the test, min.
If necessary, a different temperature regime can be created, taking into account real fire conditions.
6.2 The deviation H of the average measured temperature in the furnace T cv (5.4.2) from the value of T calculated using formula (1) is determined as a percentage using the formula
n= Tcv T T 100 .
The average measured temperature Tav in the furnace is taken to be the arithmetic mean of the readings of the furnace thermocouples at time t.
The temperatures corresponding to dependence (1), as well as the permissible deviations from them of the average measured temperatures are given in Table 1.
Table 1
When testing structures made of non-combustible materials on individual furnace thermocouples, after 10 minutes of testing, the temperature deviation from the standard temperature regime is allowed by no more than 100°C.
For other designs, such deviations should not exceed 200°C.
7 SPECIMENS FOR TESTING STRUCTURES
7.1 Specimens for testing structures must have design dimensions. If it is not possible to test samples of this size, then minimum dimensions samples are accepted according to the standards for testing structures of the relevant types, taking into account 5.2.2.
7.2 Materials and parts of samples to be tested, including butt joints walls, partitions, ceilings, coverings and other structures must comply technical documentation for their production and use.
At the request of the testing laboratory, the properties of construction materials are, if necessary, controlled on their standard samples, manufactured specifically for this purpose from the same materials simultaneously with the manufacture of structures. Before testing, control standard samples of materials must be in the same conditions as experimental samples of structures, and their tests are carried out in accordance with current standards.
7.3 The moisture content of the sample must be technical specifications and be dynamically balanced with the environment with relative humidity (60±15)% at a temperature of (20±10)°C.
The moisture content of the sample is determined directly on the sample or on a representative part of it.
To obtain dynamically balanced humidity, natural or artificial drying of samples is allowed at an air temperature not exceeding 60°C.
7.4 To test a structure of the same type, two identical samples must be made.
The samples must be accompanied by the necessary set of technical documentation.
7.5 When conducting certification tests, samples must be taken in accordance with the requirements of the adopted certification scheme.
8 TESTING
8.1 Tests are carried out at an ambient temperature from 1 to 40°C and at an air speed of no more than 0.5 m/s, unless the conditions of use of the structure require other test conditions.
The ambient temperature is measured at a distance no closer than 1 m from the surface of the sample.
The temperature in the oven and in the room must be stabilized 2 hours before the start of testing.
8.2 During the test the following is recorded:
Time of occurrence of limiting states and their type (section 9);
The temperature in the oven, on the unheated surface of the structure, as well as in other pre-heated designated places;
Excessive pressure in the furnace when testing structures whose fire resistance is determined by the limit states specified in 9.1.2 and 9.1.3;
Deformations of load-bearing structures;
Time of flame appearance on the unheated surface of the sample;
The time of appearance and the nature of cracks, holes, delaminations, as well as other phenomena (for example, violation of support conditions, the appearance of smoke).
The given list of measured parameters and recorded phenomena can be supplemented and changed in accordance with the requirements of test methods for specific types of structures.
8.3 The test must continue until the occurrence of one or, if possible, sequentially all limit states standardized for a given design.
9 LIMIT STATES
9.1 The following main types of limit states of building structures for fire resistance are distinguished.
9.1.1 Loss bearing capacity due to collapse of the structure or the occurrence of extreme deformations (R).
9.1.2 Loss of integrity as a result of the formation of through cracks or holes in structures through which combustion products or flames penetrate onto an unheated surface (E).
9.1.3 Loss of thermal insulation capacity due to an increase in temperature on the unheated surface of the structure to the limiting values for a given structure (I).
9.2 Additional limit states of structures and criteria for their occurrence, if necessary, are established in the standards for testing specific structures.
10 DESIGNATIONS OF FIRE RESISTANCE LIMITS OF STRUCTURES
The designation of the fire resistance limit of a building structure consists of symbols limit states normalized for a given design (see 9.1) and a figure corresponding to the time to achieve one of these states (the first in time) in minutes.
For example:
R 120 - fire resistance limit 120 min - for loss of load-bearing capacity;
RE 60 - fire resistance limit 60 min - for loss of load-bearing capacity and loss of integrity, regardless of which of the two limit states occurs earlier;
REI 30 - fire resistance limit 30 min - for loss of load-bearing capacity, integrity and thermal insulation capacity, regardless of which of the three limit states occurs earlier.
When drawing up a test report and issuing a certificate, the limit state for which the fire resistance limit of the structure is established should be indicated.
If different fire resistance limits are standardized (or established) for a structure for different limit states, the designation of the fire resistance limit consists of two or three parts, separated by a slash.
For example:
R 120 / EI 60 - fire resistance limit 120 min - for loss of load-bearing capacity; fire resistance limit 60 minutes - for loss of integrity or thermal insulation ability, regardless of which of the last two limit states occurs earlier.
At different meanings fire resistance limits of the same structure for different limit states, fire resistance limits are designated in descending order.
The digital indicator in the designation of the fire resistance limit must correspond to one of the numbers in the following series: 15, 30, 45, 60, 90, 120, 150, 180, 240, 360.
11 EVALUATION OF TEST RESULTS
The fire resistance limit of a structure (in minutes) is determined as the arithmetic average of the test results of two samples. In this case, the maximum and minimum values of the fire resistance limits of the two tested samples should not differ by more than 20% (from the larger value). If the results differ from each other by more than 20%, an additional test must be carried out, and the fire resistance limit is determined as the arithmetic mean of the two lower values.
In designating the fire resistance limit of a structure, the arithmetic average of the test results is reduced to the nearest smaller value from the series of numbers given in Section 10.
The results obtained during testing can be used to assess fire resistance using calculation methods of other similar ones (by shape, materials, design) structures.
12 TEST REPORT
The test report must contain the following data:
1) name of the organization conducting the test;
2) name of the customer;
3) the date and conditions of the test, and, if necessary, the date of manufacture of the samples;
4) name of the product, information about the manufacturer, trademark and marking of the sample, indicating the technical documentation for the design;
5) designation of the standard for the test method of this design;
6) sketches and descriptions of tested samples, data on control measurements of the state of the samples, physical and mechanical properties of materials and their humidity;
7) conditions for supporting and fastening samples, information about butt joints;
8) for structures tested under load - information about the load accepted for testing and loading diagrams;
9) for asymmetrical structural samples - indication of the side subjected to thermal influence;
10) observations during testing (graphs, photographs, etc.), start and end times of the test;
11) processing of test results, their assessment, indicating the type and nature of the limit state and fire resistance limit;
12) validity period of the protocol.
APPENDIX A
(required)
SAFETY REQUIREMENTS FOR CARRYING OUT
TESTS
1 Among the personnel servicing the test equipment there must be a person responsible for safety precautions.
2 When performing structural tests, it is necessary to ensure the availability of one 50-kg portable powder fire extinguisher, portable CO2 extinguisher; fire hose with a diameter of at least 25 mm under pressure.
4 When testing structures, it is necessary to: determine danger zone there is at least 1.5 m around the furnace, into which unauthorized persons are prohibited from entering during the test; take measures to protect the health of persons conducting tests if destruction, overturning or cracking of the structure is expected as a result of the test (for example, installing supports, protective nets). Measures must be taken to protect the structures of the furnace itself.
5 The laboratory premises must have natural or mechanical ventilation, providing work area for persons conducting tests, sufficient visibility and conditions reliable operation without breathing apparatus and thermal protective clothing during the entire test period.
6 If necessary, the area of the measuring and control post in the laboratory must be protected from penetration flue gases by creating overpressure air.
7 The fuel supply system must be equipped with light and/or audible alarm systems.
UDC 624.001.4:006.354 MKS 13.220.50 Zh39 OKSTU 5260
Key words: fire resistance, fire resistance limit, building construction, General requirements
Editor V.P. Ogurtsov Technical editor V.N. Prusakova Corrector V.I. Kanurkina Computer layout E.N. Martemyanova
Ed. persons No. 02354 dated July 14, 2000. Delivered for recruitment on 06/09/2003. Signed for publication on July 4, 2003. Uel. oven l. 1.40. Academic ed. l. 0.83. Circulation 146 copies. From 11195. Zak. 552.
IPK Standards Publishing House, 107076 Moscow, Kolodezny per., 14. e-mail:
Typed at the Publishing House on a PC
Branch of IPK Standards Publishing House - type. "Moscow Printer", 105062 Moscow, Lyalin lane, 6.
GOST 30247.0-94
(ISO 834-75)
Group Zh39
INTERSTATE STANDARD
BUILDING STRUCTURES
FIRE RESISTANCE TEST METHODS
General requirements
Elements of building constructions. Fire-resistance test methods. General requirements
ISS 13.220.50
OKSTU 5260
5800
Date of introduction 1996-01-01
Preface
Preface
1 DEVELOPED by the State Central Research and Design-Experimental Institute for Complex Problems of Building Structures and Structures named after V.A. Kucherenko (TsNIISK named after Kucherenko) of the Ministry of Construction of Russia, the Center for Fire Research and Thermal Protection in Construction TsNIISK (CPITZS TsNIISK) and the All-Russian Scientific- Research Institute of Fire Defense (VNIIPO) of the Ministry of Internal Affairs of Russia
INTRODUCED by the Ministry of Construction of Russia
2 ADOPTED by the Interstate Scientific and Technical Commission for Standardization and Technical Regulation in Construction (INTKS) on November 17, 1994.
State name | Name of body government controlled construction |
The Republic of Azerbaijan | State Construction Committee of the Azerbaijan Republic |
Republic of Armenia | State Architecture of the Republic of Armenia |
The Republic of Kazakhstan | Ministry of Construction of the Republic of Kazakhstan |
Republic of Kyrgyzstan | Gosstroy of the Kyrgyz Republic |
The Republic of Moldova | Ministry of Architecture and Construction of the Republic of Moldova |
Russian Federation | Ministry of Construction of Russia |
The Republic of Tajikistan | State Construction Committee of the Republic of Tajikistan |
3 This standard is an authentic text of ISO 834-75* Fire resistance test - Elements of building constructions. "Fire resistance tests. Building structures"
________________
* Access to international and foreign documents mentioned in the text can be obtained by contacting Customer Support. - Database manufacturer's note.
4 ENTERED INTO EFFECT on January 1, 1996 as a state standard of the Russian Federation by Resolution of the Ministry of Construction of Russia dated March 23, 1995 N 18-26
5 INSTEAD ST SEV 1000-78
6 REPUBLICATION. May 2003
1 AREA OF USE
This standard regulates the general requirements for testing methods of building structures and elements of engineering systems (hereinafter referred to as structures) for fire resistance under standard conditions of thermal exposure and is used to establish fire resistance limits.
The standard is fundamental in relation to standards for fire resistance testing methods for specific types of structures.
When establishing the fire resistance limits of structures in order to determine the possibility of their use in accordance with the fire safety requirements of regulatory documents (including certification), the methods established by this standard should be used.
2 REGULATORY REFERENCES
3 DEFINITIONS
The following terms are used in this standard.
3.1 fire resistance of the structure: According to GOST 12.1.033.
3.2 fire resistance limit of the structure: According to GOST 12.1.033.
3.3 limit state of the structure for fire resistance: The condition of a structure in which it loses its ability to maintain load-bearing and/or enclosing functions in a fire.
4 ESSENCE OF TEST METHODS
The essence of the methods is to determine the time from the beginning of thermal impact on the structure, in accordance with this standard, until the onset of one or successively several limit states for fire resistance, taking into account the functional purpose of the structure.
5 STAND EQUIPMENT
5.1 Bench equipment includes:
Test furnaces with a fuel supply and combustion system (hereinafter referred to as furnaces);
Devices for installing the sample on the furnace, ensuring compliance with the conditions of its fastening and loading;
Systems for measuring and recording parameters, including equipment for filming, photography or video recording.
5.2 Furnaces
5.2.1 Furnaces must provide the ability to test structural samples under the required conditions of loading, support, temperature and pressure specified in this standard and in the standards for testing methods for specific types of structures.
5.2.2 The main dimensions of the furnace openings must be such as to ensure the possibility of testing samples of structures of designed sizes.
If it is not possible to test samples of design sizes, their dimensions and furnace openings must be such as to ensure the conditions of thermal exposure to the sample, regulated by standards for fire resistance testing methods for specific types of structures.
The depth of the fire chamber of furnaces must be at least 0.8 m.
5.2.3 The design of the furnace masonry, including its outer surface, must provide the possibility of installing and fastening the sample, equipment and fixtures.
5.2.4 The temperature in the furnace and its deviations during the test must comply with the requirements of section 6.
5.2.5 The temperature regime of the furnaces must be ensured by burning liquid fuel or gas.
5.2.6 The combustion system must be adjustable.
5.2.7 The burner flame should not touch the surface of the structures being tested.
5.2.8 When testing structures whose fire resistance limit is determined by the limit states specified in 9.1.2 and 9.1.3, excess pressure must be ensured in the fire space of the furnace.
It is allowed not to control excess pressure when testing the fire resistance of load-bearing rod structures (columns, beams, trusses, etc.), as well as in cases where its influence on the fire resistance limit of the structure is insignificant (reinforced concrete, stone, etc. structures).
5.3 Furnaces for testing load-bearing structures must be equipped with loading and support devices that ensure loading of the sample in accordance with its design diagram.
5.4 Requirements for measuring systems
5.4.1 During testing, the following parameters:
Parameters of the environment in the fire chamber of the furnace - temperature and pressure (taking into account 5.2.8);
Loading and deformation parameters when testing load-bearing structures.
5.4.2 The temperature of the medium in the fire chamber of the furnace must be measured by thermoelectric converters (thermocouples) in at least five places. In this case, for every 1.5 m of the opening of the furnace intended for testing enclosing structures, and for every 0.5 m of the length (or height) of the furnace intended for testing rod structures, at least one thermocouple must be installed.
The soldered end of the thermocouple should be installed at a distance of 100 mm from the surface of the calibration sample.
The distance from the soldered end of the thermocouples to the furnace walls must be at least 200 mm.
5.4.3 The temperature in the furnace is measured by thermocouples with electrodes with a diameter of 0.75 to 3.2 mm. The hot junction of the electrodes must be free. The protective casing (cylinder) of the thermocouple must be removed (cut and removed) at a length of (25±10) mm from its soldered end.
5.4.4 To measure the temperature of samples, including on the unheated surface of enclosing structures, thermocouples with electrodes with a diameter of no more than 0.75 mm are used.
The method of attaching thermocouples to the test sample of the structure must ensure an accuracy of measuring the temperature of the sample within ±5%.
In addition, to determine the temperature at any point on the unheated surface of the structure where the greatest increase in temperature is expected, it is allowed to use a portable thermocouple equipped with a holder or other technical means.
5.4.5 The use of thermocouples with a protective casing or with electrodes of other diameters is permitted, provided that their sensitivity is not lower and the time constant is not higher than that of thermocouples made in accordance with 5.4.3 and 5.4.4.
5.4.6 To record measured temperatures, instruments of at least accuracy class 1 should be used.
5.4.7 Instruments intended for measuring pressure in a furnace and recording the results must provide a measurement accuracy of ±2.0 Pa.
5.4.8 Measuring instruments must provide continuous recording or discrete recording of parameters with an interval of no more than 60 s.
5.4.9 To determine the loss of integrity of enclosing structures, use a cotton or natural wool swab.
The dimensions of the tampon should be 100-10030 mm, weight - from 3 to 4 g. Before use, the tampon is kept in a drying cabinet at a temperature of (105±5)°C for 24 hours. The swab is removed from the drying oven no earlier than 30 minutes before the start of the test. Repeated use of a tampon is not allowed.
5.5 Calibration of bench equipment
5.5.1 Calibration of furnaces consists of monitoring the temperature and pressure in the furnace volume. In this case, a calibration sample is placed in the opening of the furnace for testing structures.
5.5.2 The design of the calibration sample must have a fire resistance rating not less than the calibration time.
5.5.3 The calibration sample for furnaces intended for testing enclosing structures must be made of a reinforced concrete slab with a thickness of at least 150 mm.
5.5.4 The calibration sample for furnaces intended for testing rod structures must be made in the form of a reinforced concrete column with a height of at least 2.5 m and a cross-section of at least 0.04 m.
5.5.5 Calibration duration - at least 90 minutes.
6 TEMPERATURE CONDITION
6.1 During the testing and calibration process, a standard temperature regime must be created in furnaces, characterized by the following relationship:
Where T- temperature in the oven corresponding to the time t, °C;
Temperature in the furnace before the start of thermal exposure (taken to be equal to the ambient temperature), °C;
t- time calculated from the beginning of the test, min.
If necessary, a different temperature regime can be created, taking into account real fire conditions.
6.2 Deviation H average measured temperature in the furnace (5.4.2) from the value T, calculated using formula (1), is determined as a percentage using the formula
The average measured temperature in the furnace is taken as the arithmetic mean of the readings of the furnace thermocouples at a time t.
The temperatures corresponding to dependence (1), as well as the permissible deviations from them of the average measured temperatures are given in Table 1.
Table 1
t, min | Permissible deviation value H, % |
|
When testing structures made of non-combustible materials on individual furnace thermocouples, after 10 minutes of testing, the temperature deviation from the standard temperature regime is allowed by no more than 100°C.
For other designs, such deviations should not exceed 200°C.
7 SPECIMENS FOR TESTING STRUCTURES
7.1 Specimens for testing structures must have design dimensions. If it is not possible to test samples of such sizes, then the minimum sample sizes are taken according to the standards for testing structures of the corresponding types, taking into account 5.2.2.
7.2 Materials and parts of samples to be tested, including butt joints of walls, partitions, ceilings, coatings and other structures, must comply with the technical documentation for their manufacture and use.
At the request of the testing laboratory, the properties of construction materials are, if necessary, controlled on their standard samples, manufactured specifically for this purpose from the same materials simultaneously with the manufacture of structures. Before testing, control standard samples of materials must be in the same conditions as experimental samples of structures, and their tests are carried out in accordance with current standards.
7.3 The humidity of the sample must comply with the specifications and be dynamically balanced with the environment with a relative humidity of (60±15)% at a temperature of (20±10)°C.
The moisture content of the sample is determined directly on the sample or on a representative part of it.
To obtain dynamically balanced humidity, natural or artificial drying of samples is allowed at an air temperature not exceeding 60°C.
7.4 To test a structure of the same type, two identical samples must be made.
The samples must be accompanied by the necessary set of technical documentation.
7.5 When conducting certification tests, samples must be taken in accordance with the requirements of the adopted certification scheme.
8 TESTING
8.1 Tests are carried out at an ambient temperature from 1 to 40°C and at an air speed of no more than 0.5 m/s, unless the conditions of use of the structure require other test conditions.
The ambient temperature is measured at a distance no closer than 1 m from the surface of the sample.
The temperature in the oven and in the room must be stabilized 2 hours before the start of testing.
8.2 During the test the following is recorded:
Time of occurrence of limiting states and their type (section 9);
Temperature in the oven, on the unheated surface of the structure, as well as in other pre-installed places;
Excessive pressure in the furnace when testing structures whose fire resistance is determined by the limit states specified in 9.1.2 and 9.1.3;
Deformations of load-bearing structures;
Time of flame appearance on the unheated surface of the sample;
The time of appearance and the nature of cracks, holes, peelings, as well as other phenomena (for example, violation of support conditions, the appearance of smoke).
The given list of measured parameters and recorded phenomena can be supplemented and changed in accordance with the requirements of test methods for specific types of structures.
8.3 The test must continue until the occurrence of one or, if possible, sequentially all limit states standardized for a given design.
9 LIMIT STATES
9.1 The following main types of limit states of building structures for fire resistance are distinguished.
9.1.1 Loss of load-bearing capacity due to collapse of the structure or the occurrence of extreme deformations (R).
9.1.2 Loss of integrity as a result of the formation of through cracks or holes in structures through which combustion products or flames penetrate onto an unheated surface (E).
9.1.3 Loss of thermal insulation capacity due to an increase in temperature on the unheated surface of the structure to the limiting values for a given structure (I).
9.2 Additional limit states of structures and criteria for their occurrence, if necessary, are established in the standards for testing specific structures.
10 DESIGNATIONS OF FIRE RESISTANCE LIMITS OF STRUCTURES
The designation of the fire resistance limit of a building structure consists of symbols of the limit states normalized for a given structure (see 9.1) and a number corresponding to the time to achieve one of these states (the first in time) in minutes.
For example:
R 120 - fire resistance limit 120 min - for loss of load-bearing capacity;
RE 60 - fire resistance limit 60 min - for loss of load-bearing capacity and loss of integrity, regardless of which of the two limit states occurs earlier;
REI 30 - fire resistance limit 30 min - for loss of load-bearing capacity, integrity and thermal insulation capacity, regardless of which of the three limit states occurs earlier.
When drawing up a test report and issuing a certificate, the limit state for which the fire resistance limit of the structure is established should be indicated.
If different fire resistance limits are standardized (or established) for a structure for different limit states, the designation of the fire resistance limit consists of two or three parts, separated by a slash.
For example:
R 120 / EI 60 - fire resistance limit 120 min - for loss of load-bearing capacity; fire resistance limit 60 minutes - for loss of integrity or thermal insulation ability, regardless of which of the last two limit states occurs earlier.
For different values of fire resistance limits of the same structure for different limit states, fire resistance limits are designated in descending order.
The digital indicator in the designation of the fire resistance limit must correspond to one of the numbers in the following series: 15, 30, 45, 60, 90, 120, 150, 180, 240, 360.
11 EVALUATION OF TEST RESULTS
The fire resistance limit of a structure (in minutes) is determined as the arithmetic average of the test results of two samples. In this case, the maximum and minimum values of the fire resistance limits of the two tested samples should not differ by more than 20% (from the larger value). If the results differ from each other by more than 20%, an additional test must be carried out, and the fire resistance limit is determined as the arithmetic mean of the two lower values.
In designating the fire resistance limit of a structure, the arithmetic average of the test results is reduced to the nearest smaller value from the series of numbers given in Section 10.
The results obtained during testing can be used to evaluate the fire resistance using calculation methods of other similar (in shape, materials, design) structures.
12 TEST REPORT
The test report must contain the following data:
1) name of the organization conducting the test;
2) name of the customer;
3) the date and conditions of the test, and, if necessary, the date of manufacture of the samples;
4) name of the product, information about the manufacturer, trademark and marking of the sample, indicating the technical documentation for the design;
5) designation of the standard for the test method of this design;
6) sketches and descriptions of tested samples, data on control measurements of the state of the samples, physical and mechanical properties of materials and their humidity;
7) conditions for supporting and fastening samples, information about butt joints;
8) for structures tested under load - information about the load accepted for testing and loading diagrams;
9) for asymmetrical structural samples - indication of the side subjected to thermal influence;
10) observations during testing (graphs, photographs, etc.), start and end times of the test;
11) processing of test results, their assessment, indicating the type and nature of the limit state and fire resistance limit;
12) validity period of the protocol.
Appendix A (mandatory). SAFETY REQUIREMENTS FOR TESTING
Appendix A
(required)
1 Among the personnel servicing the test equipment there must be a person responsible for safety precautions.
2 When performing structural testing, it is necessary to ensure that one 50 kg portable dry powder fire extinguisher, a portable CO extinguisher is available; fire hose with a diameter of at least 25 mm under pressure.
4 When testing structures, it is necessary to: determine a dangerous zone around the furnace of at least 1.5 m, into which unauthorized persons are prohibited from entering during testing; take measures to protect the health of persons conducting tests if destruction, overturning or cracking of the structure is expected as a result of the test (for example, installing supports, protective nets). Measures must be taken to protect the structures of the furnace itself.
5 The laboratory premises must have natural or mechanical ventilation that provides sufficient visibility in the working area for persons conducting tests and conditions for reliable work without breathing apparatus and thermal protective clothing during the entire test period.
6 If necessary, the area of the measuring and control station in the laboratory room must be protected from the penetration of flue gases by creating excess air pressure.
7 The fuel supply system must be equipped with light and/or audible alarm systems.
UDC 624.001.4:006.354 | ISS 13.220.50 | OKSTU 5260 |
|
Key words: fire resistance, fire resistance limit, building structures, general requirements |
|||
Electronic document text
prepared by Kodeks JSC and verified against:
official publication
M.: IPK Standards Publishing House, 2003
Elements of building constructions fire-resistance test methods. General requirements
Instead of ST SEV 1000-78
1 area of use
This standard regulates the general requirements for testing methods of building structures and elements of engineering systems (hereinafter referred to as structures) for fire resistance under standard conditions of thermal exposure and is used to establish fire resistance limits.
The standard is fundamental in relation to standards for fire resistance testing methods for specific types of structures.
When establishing the fire resistance limits of structures in order to determine the possibility of their use in accordance with the fire safety requirements of regulatory documents (including certification), the methods established by this standard should be used.
3. Definitions
The following terms are used in this standard.
Fire resistance of the structure- according to ST SEV 383.
Fire resistance limit of the structure- according to ST SEV 383.
Limit state of a structure for fire resistance- the state of a structure in which it loses its ability to maintain load-bearing and/or enclosing functions in fire conditions.
4. Essence of test methods
The essence of the test methods is to determine the time from the beginning of thermal impact on a structure in accordance with this standard until the onset of one or successively several limit states for fire resistance, taking into account the functional purpose of the structure.
5. Bench equipment
5.1. Stand equipment includes:
Test furnaces with a fuel supply and combustion system (hereinafter referred to as furnaces);
Devices for installing the sample on the furnace, ensuring compliance with the conditions of its fastening and loading;
Systems for measuring and recording parameters, including equipment for filming, photography or video recording.
5.2.1. Furnaces must provide the ability to test structural samples under the required conditions of loading, support, temperature and pressure specified in this standard and in the standards for testing methods for specific types of structures.
5.2.2. The main dimensions of furnace openings must be such as to ensure the possibility of testing samples of structures of designed sizes.
If it is not possible to test samples of design sizes, their dimensions and furnace openings must be such as to ensure the conditions of thermal exposure to the sample, regulated by standards for fire resistance testing methods for specific types of structures.
The depth of the furnace fire chamber must be at least 0.8 m.
5.2.3. The design of the furnace masonry, including its outer surface, must provide the possibility of installing and fastening the sample, equipment and fixtures.
5.2.4. The temperature in the furnace and its deviations during the test must comply with the requirements of section 6.
5.2.5. The temperature regime of the furnaces must be ensured by burning liquid fuel or gas.
5.2.6. The combustion system must be adjustable.
5.2.7. The burner flame should not touch the surface of the structures being tested.
5.2.8. When testing structures whose fire resistance limit is determined by the limit states specified in 9.1.2 and 9.1.3, excess pressure must be ensured in the fire space of the furnace.
It is allowed not to control excess pressure when testing the fire resistance of load-bearing rod structures (columns, beams, trusses, etc.), as well as in cases where its influence on the fire resistance limit of the structure is insignificant (reinforced concrete, etc. structures).
5.3. Furnaces for testing load-bearing structures must be equipped with loading and supporting devices that ensure loading of the sample in accordance with its design diagram.
5.4. Requirements for measurement systems
5.4.1. During testing, the following parameters should be measured and recorded:
Environments in the fire chamber of the furnace - temperature and pressure (taking into account 5.2.8);
Loads and deformations when testing load-bearing structures.
5.4.2. The temperature of the medium in the fire chamber of the furnace must be measured by thermoelectric converters (thermocouples) in at least five places. In this case, for every 1.5 openings of the furnace intended for testing enclosing structures, and for every 0.5 m of the length (or height) of the furnace intended for testing rod structures, at least one thermocouple must be installed.
The soldered end of the thermocouple should be installed at a distance of 100 mm from the surface of the calibration sample.
The distance from the soldered end of the thermocouples to the furnace walls must be at least 200 mm.
5.4.3. The temperature in the furnace is measured by thermocouples with electrodes with a diameter of 0.75 to 3.2 mm. The hot junction of the electrodes must be free. The protective casing (cylinder) of the thermocouple must be removed (cut and removed) at a length () mm from its soldered end.
5.4.4. To measure the temperature of samples, including on the unheated surface of enclosing structures, thermocouples with electrodes with a diameter of no more than 0.75 mm are used.
The method of attaching thermocouples to the test sample of the structure must ensure an accuracy of measuring the temperature of the sample within %.
In addition, to determine the temperature at any point on the unheated surface of the structure where the greatest increase in temperature is expected, it is allowed to use a portable thermocouple equipped with a holder or other technical means.
5.4.5. The use of thermocouples with a protective casing or with electrodes of other diameters is permitted, provided that their sensitivity is not lower and the time constant is not higher than that of thermocouples made in accordance with 5.4.3 and 5.4.4.
5.4.6. To record measured temperatures, instruments of at least accuracy class 1 should be used.
5.4.7. Instruments designed to measure pressure in a furnace and record the results must ensure accurate measurement of Pa.
5.4.8. Measuring instruments must provide continuous recording or discrete recording of parameters with an interval of no more than 60 s.
5.4.9. To determine the loss of integrity of enclosing structures, use a cotton or natural wool swab.
The size of the tampon should be 100x100x30 mm, weight - from 3 to 4 g. Before use, the tampon should be kept in a drying cabinet at a temperature of ()°C for 24 hours. The swab is removed from the drying oven no earlier than 30 minutes before the start of the test. Repeated use of a tampon is not allowed.
5.5. Calibration of bench equipment
5.5.1. Calibration of furnaces involves monitoring the temperature and pressure in the furnace volume. In this case, a calibration sample is placed in the opening of the furnace for testing structures.
5.5.2. The design of the calibration sample must have a fire resistance rating no less than the calibration time.
5.5.3. The calibration sample for furnaces intended for testing enclosing structures must be made of a reinforced concrete slab with a thickness of at least 150 mm.
5.5.4. The calibration sample for furnaces intended for testing rod structures must be made in the form of a reinforced concrete column with a height of at least 2.5 m and a cross-section of at least 0.04.
5.5.5. Calibration duration is at least 90 minutes.
6. Temperature
6.1. During testing and calibration in furnaces, a standard temperature regime must be created, characterized by the following relationship:
, (1)
where T is the temperature in the furnace corresponding to time t, °C;
Temperature in the furnace before the start of thermal exposure (assumed equal to the ambient temperature), °C;
t - time calculated from the beginning of the test, min.
If necessary, a different temperature regime can be created, taking into account real fire conditions.
6.2. The deviation H of the average measured temperature in the furnace (5.4.2) from the value T calculated using formula (1) is determined as a percentage using the formula
. (2)
The average measured temperature in the furnace is taken to be the arithmetic mean of the readings of the furnace thermocouples at time t.
The temperatures corresponding to the dependence, as well as the permissible deviations from them of the average measured temperatures are given in Table 1.
Table 1
| t, min | T - T_0, °C | Allowed value deviations H, % |
| 5 10 |
556 659 |
+-15 |
| 15 30 |
718 821 |
+-10 |
| 45 60 90 120 150 180 240 360 |
875 925 986 1029 1060 1090 1133 1193 |
When testing structures made of non-combustible materials on individual furnace thermocouples, after 10 minutes of testing, a temperature deviation from the standard temperature regime is allowed by no more than 100°C.
For other designs, such deviations should not exceed 200°C.
7. Samples for testing structures
7.1. Samples for testing structures must have design dimensions. If it is not possible to test samples of such sizes, then the minimum sample sizes are taken according to the standards for testing structures of the corresponding types, taking into account 5.2.2.
7.2. Materials and parts of samples to be tested, including butt joints of walls, partitions, ceilings, coatings and other structures, must comply with the technical documentation for their manufacture and use.
At the request of the testing laboratory, the properties of construction materials are, if necessary, controlled on their standard samples, manufactured specifically for this purpose from the same materials simultaneously with the manufacture of structures. Before testing, control standard samples of materials must be in the same conditions as experimental samples of structures, and their tests are carried out in accordance with current standards.
7.3. The sample's moisture content must meet specifications and be dynamically balanced with the surrounding environment at ()% relative humidity at ()°C.
The moisture content of the sample is determined directly on the sample or on a representative part of it.
To obtain dynamically balanced humidity, natural or artificial drying of samples is allowed at an air temperature not exceeding 60°C.
7.4. To test a structure of the same type, two identical samples must be made.
The samples must be accompanied by the necessary set of technical documentation.
7.5. When conducting certification tests, samples must be taken in accordance with the requirements of the adopted certification scheme.
8. Testing
8.1. Tests are carried out at ambient temperatures from 1 to 40°C and at an air speed of no more than 0.5 m/s, unless the conditions of use of the structure require other test conditions.
The ambient temperature is measured at a distance no closer than 1 m from the surface of the sample.
The temperature in the oven and in the room must be stabilized 2 hours before the start of testing.
8.2. During the test the following is recorded:
Time of occurrence of limiting states and their type (section 9);
Temperature in the oven, on the unheated surface of the structure, as well as in other pre-installed places;
Excessive pressure in the furnace when testing structures whose fire resistance is determined by the limit states specified in 9.1.2 and 9.1.3;
Deformations of load-bearing structures;
Time of flame appearance on the unheated surface of the sample;
The time of appearance and the nature of cracks, holes, delaminations, as well as other phenomena (for example, violation of support conditions, the appearance of smoke).
The given list of measured parameters and recorded phenomena can be supplemented and changed in accordance with the requirements of test methods for specific types of structures.
8.3. The test must continue until the occurrence of one or, if possible, sequentially all limit states standardized for a given design.
9. Limit states
9.1. The following main types of limit states of building structures for fire resistance are distinguished.
9.1.1. Loss of load-bearing capacity due to collapse of the structure or the occurrence of extreme deformations (R).
9.1.2. Loss of integrity as a result of the formation of through cracks or holes in structures through which combustion products or flames penetrate onto an unheated surface (E).
9.1.3. Loss of thermal insulation ability due to an increase in temperature on the unheated surface of the structure to the maximum values for a given structure (I).
9.2. Additional limit states of structures and criteria for their occurrence, if necessary, are established in the standards for testing specific structures.
10. Designations of fire resistance limits of structures
The designation of the fire resistance limit of a building structure consists of symbols of the limit states normalized for a given structure (see 9.1) and a number corresponding to the time to achieve one of these states (the first in time) in minutes.
For example:
R 120 - fire resistance limit of 120 minutes for loss of load-bearing capacity;
RE 60 - fire resistance limit of 60 minutes for loss of load-bearing capacity and loss of integrity, regardless of which of the two limit states occurs earlier;
REI 30 - fire resistance limit of 30 minutes for loss of load-bearing capacity, integrity and thermal insulation capacity, regardless of which of the three limit states occurs earlier.
When drawing up a test report and issuing a certificate, the limit state for which the fire resistance limit of the structure is established should be indicated.
If different fire resistance limits are standardized (or established) for a structure for different limit states, the designation of the fire resistance limit consists of two or three parts, separated by a slash.
For example:
R 120/EI 60 - fire resistance limit of 120 minutes for loss of load-bearing capacity; fire resistance limit of 60 minutes for loss of integrity and heat-insulating ability, regardless of which of the last two limiting states occurs earlier.
For different values of fire resistance limits of the same structure for different limit states, fire resistance limits are designated in descending order.
The digital indicator in the designation of the fire resistance limit must correspond to one of the numbers in the following series: 15, 30, 45, 60, 90, 120, 150, 180, 240, 360.
11. Evaluation of test results
The fire resistance limit of a structure in minutes is determined as the arithmetic average of the test results of two samples. In this case, the maximum and minimum values of the fire resistance limits of the two tested samples should not differ by more than 20% (from the larger value). If the results differ from each other by more than 20%, an additional test must be carried out, and the fire resistance limit is determined as the arithmetic mean of the two lower values.
In designating the fire resistance limit of a structure, the arithmetic average of the test results is reduced to the nearest smaller value from the series of numbers given in section 10.
The results obtained during testing can be used to evaluate the fire resistance using calculation methods of other similar (in shape, materials, design) structures.
12. Test report
The test report must contain the following data:
1) name of the organization conducting the test;
2) name of the customer;
3) the date and conditions of the test, and, if necessary, the date of manufacture of the samples;
4) name of the product, information about the manufacturer, trademark and marking of the sample, indicating the technical documentation for the design;
5) designation of the standard for the test method of this design;
6) sketches and descriptions of tested samples, data on control measurements of the state of the samples, physical and mechanical properties of materials and their humidity;
7) conditions for supporting and fastening samples, information about butt joints;
8) for structures tested under load - information about the load accepted for testing and loading diagrams;
9) for asymmetrical structural samples - indication of the side subjected to thermal influence;
10) observations during testing (graphs, photographs, etc.), start and end times of the test;
11) processing of test results and their assessment, indicating the type and nature of the limit state and fire resistance limit;
12) validity period of the protocol.
GOST 30247.0-94
INTERSTATE STANDARD
BUILDING STRUCTURES
Fire resistance test methods
General requirements
Interstate Scientific and Technical Commission
on standardization and technical regulation
in construction (MNTKS)
Preface
1 DEVELOPED by the State Central Research and Design-Experimental Institute of Complex Problems of Building Structures and Structures named after V.A. Kucherenko (TsNIISK named after Kucherenko) State Scientific Center of the Russian Federation "Construction" of the Ministry of Construction of Russia together with the All-Russian Research Institute of Fire Defense (VNIIPO) of the Ministry of Internal Affairs of Russia and the Center for Fire Research and Thermal Protection in Construction TsNIISK (TsPITSS TsNIISK).
INTRODUCED by the Ministry of Construction of Russia
2 ADOPTED by the Interstate Scientific and Technical Commission for Standardization and Technical Regulation in Construction (INTKS) on November 17, 1994.
|
State name |
Name of the state construction management body |
|
The Republic of Azerbaijan |
State Construction Committee of the Azerbaijan Republic |
|
Republic of Armenia |
State Architecture of the Republic of Armenia |
|
The Republic of Kazakhstan |
Ministry of Construction of the Republic of Kazakhstan |
|
Republic of Kyrgyzstan |
Gosstroy of the Kyrgyz Republic |
|
The Republic of Moldova |
Ministry of Architecture and Construction of the Republic of Moldova |
|
Russian Federation |
Ministry of Construction of Russia |
|
The Republic of Tajikistan |
State Construction Committee of the Republic of Tajikistan |
3.2 The fire resistance limit of the structure is according to the CMEA standard 383-87.
3.3 The limiting state of a structure for fire resistance is the state of a structure in which it loses the ability to maintain one of its fire-fighting functions.
4 ESSENCE OF TEST METHODS
The essence of the methods is to determine the time from the beginning of thermal impact on a structure in accordance with this standard until the onset of one or successively several limit states for fire resistance, taking into account the functional purpose of the structure.
5 STAND EQUIPMENT
5.1 Bench equipment includes:
Test furnaces with a fuel supply and combustion system (hereinafter referred to as furnaces);
Devices for installing the sample on the furnace, ensuring compliance with the conditions of its fastening and loading;
Systems for measuring and recording parameters, including equipment for filming, photography or video recording.
5.2 Test ovens
5.2.1 Test furnaces must be capable of testing specimen structures under the required conditions of loading, support, temperature and pressure specified in this standard and in the standards for test methods for specific types of structures.
If it is not possible to test samples of design sizes, their dimensions and furnace openings must be such as to ensure the conditions of thermal exposure to the sample, regulated by the standards for fire resistance testing methods for specific types of structures.
The depth of the furnace fire space must be at least 0.8 m.
5.2.3 The design of the furnace masonry, including its outer surface, must provide the possibility of installing and fastening the sample, equipment and fixtures.
5.2.4 The temperature in the furnace and its deviations during the test must comply with the requirements of this standard.
5.2.5 The temperature regime of the furnaces must be ensured by burning liquid fuel or gas.
5.2.6 The combustion system must be adjustable.
5.2.7 The burner flame should not touch the surface of the structures being tested.
Loading and deformation parameters when testing load-bearing structures;
Temperature of samples, including on the unheated surface of enclosing structures - loss of integrity of enclosing structures.
The soldered end of the thermocouple should be installed at a distance of 100 mm from the surface of the sample.
The distance from the soldered end of the thermocouples to the furnace walls must be at least 200 mm.
The method of attaching thermocouples to the test sample of the structure must ensure an accuracy of measuring the temperature of the sample within +-5%.
In addition, to determine the temperature at any point on the unheated surface of the structure where the greatest increase in temperature is expected, it is allowed to use a portable thermocouple equipped with a holder or other technical means.
5.4.5 The use of thermocouples with a protective casing or with other electrode diameters is allowed, provided that their sensitivity is not lower and the time constant is not higher than that of thermocouples made in accordance with and.
5.4.6 To record measured temperatures, instruments with accuracy class of at least 1 should be used.
5.4.7 Instruments intended for measuring pressure in a furnace and recording the results must provide measurement accuracy of +-2.0 Pa.
5.4.8 Measuring instruments must provide continuous recording or discrete recording of parameters with an interval of no more than 60 s.
The dimensions of the tampon should be 100 ´ 100 ´ 30 mm, weight from 3 to 4 g. Before use, the tampon is kept in an oven for 24 hours at a temperature of 105 ° C + - 5 ° C. The tampon should not be removed from the drying cabinet before; than 30 minutes before the start of the test. Repeated use of a tampon is not allowed.
5.5 Calibration of bench equipment
5.5.1 Calibration of furnaces consists of monitoring the temperature field and pressure in the furnace volume. In this case, a calibration sample is placed in the opening of the furnace for testing structures.
5.5.2 The design of the calibration sample must have a fire resistance rating no less than the calibration time.
5.5.3 The calibration sample for furnaces intended for testing enclosing structures must be made of a reinforced concrete slab with a thickness of at least 150 mm.
5.5.4 The calibration sample for furnaces intended for testing rod structures must be made in the form of a reinforced concrete column with a height of at least 2.5 m and a cross-section of at least 0.04 m2.
5.5.5 Calibration duration - at least 90 minutes.
6 TEMPERATURE CONDITION
6.1 During testing and calibration, a standard temperature regime must be created in test furnaces, characterized by the following dependence:
Table 1
When testing structures made of non-combustible materials on individual furnace thermocouples, after 10 minutes of testing, the temperature deviation from the standard temperature regime is allowed by no more than 100 °C.
For other designs, such deviations should not exceed 200 °C.
7 SPECIMENS FOR TESTING STRUCTURES
7.1 Specimens for testing structures must have design dimensions. If it is not possible to test samples of such sizes, then the minimum sample sizes are accepted according to the standards for testing the relevant types of structures with registration.
7.2 Materials and parts of samples to be tested, including butt joints of walls, partitions, ceilings, coatings and other structures, must comply with the technical documentation for their manufacture and use.
At the request of the testing laboratory, the properties of construction materials are, if necessary, controlled on their standard samples, manufactured specifically for this purpose from the same materials simultaneously with the manufacture of structures. Before testing, control standard samples of materials must be in the same conditions as experimental samples of structures, and their tests are carried out in accordance with current standards.
7.3 The humidity of the sample must comply with the specifications and be dynamically balanced with the environment with relative humidity (60 +- 15)% at a temperature of 20 °C +- 10 °C.
The moisture content of the sample is determined directly on the sample or on a representative part of it.
To obtain dynamically balanced humidity, natural or artificial drying of samples is allowed at an air temperature not exceeding 60 C°.
7.4 To test a structure of the same type, two identical samples must be made.
The samples must be accompanied by the necessary set of technical documentation.
7.5 When conducting certification tests, samples must be taken in accordance with the requirements of the adopted certification scheme.
8. TESTING
8.1 Tests are carried out at ambient temperatures ranging from + 1 to + 40 ° C and at an air speed of no more than 0.5 m/s, unless the conditions of use of the structure require other test conditions.
The ambient temperature and air velocity are measured at a distance of no closer than 1 m from the surface of the sample.
The temperature in the oven and in the room must be stabilized 2 hours before the start of testing.
8.2 During the test the following are recorded:
Time of occurrence of limit states and their type ();
Temperature in the oven, on the unheated surface of the structure, as well as in other pre-established places;
Excessive pressure in the furnace when testing structures whose fire resistance is determined by the limit states specified in and;
Deformations of load-bearing structures;
Time of flame appearance on the unheated surface of the sample;
The time of appearance and the nature of cracks, holes, delaminations, as well as other phenomena (for example, violation of support conditions, the appearance of smoke).
The given list of measured parameters and recorded phenomena can be supplemented and changed in accordance with the requirements of test methods for specific types of structures.
8.3 The test must continue until the occurrence of one or, if possible, sequentially all limit states standardized for a given design.
9 LIMIT STATES
9.1.1 Loss of load-bearing capacity due to collapse of the structure or the occurrence of extreme deformations ( R).
9.2 Additional limit states of structures and criteria for their occurrence, if necessary, are established in the standards for testing specific structures.
10 DESIGNATIONS OF FIRE RESISTANCE LIMITS OF STRUCTURES
The designation of the fire resistance limit of a building structure consists of symbols that are standardized for a given design of limit states (see), and a number corresponding to the time to achieve one of these states (the first in time) in minutes. For example:
R 120 - fire resistance limit 120 minutes - based on loss of load-bearing capacity;
RE 60 - fire resistance limit of 60 minutes - for loss of load-bearing capacity and loss of integrity, regardless of which of the two limit states occurs earlier;
REI 30 - fire resistance limit of 30 minutes - for loss of load-bearing capacity, integrity and thermal insulation ability, regardless of which of the three limit states occurs first.
When drawing up a test report and issuing a certificate, the limit state for which the fire resistance limit of the structure is established should be indicated.
If different fire resistance limits are standardized (or established) for a structure for different limit states, the fire resistance limit designation consists of two or three parts, separated by a slash. For example:
R 120/EI 60 - fire resistance limit of 120 minutes - for loss of load-bearing capacity / fire resistance limit of 60 minutes - for loss of integrity or thermal insulation ability, regardless of which of the last two limit states occurs earlier.
For different values of fire resistance limits of the same structure for different limit states, the designation of fire resistance limits is listed in descending order.
The digital indicator in the designation of the fire resistance limit must correspond to one of the numbers in the following series: 15, 30, 45, 60, 90, 180, 240, 360.
11 EVALUATION OF TEST RESULTS
The fire resistance limit of a structure (in min) is determined as the arithmetic average of the test results of two samples. In this case, the maximum and minimum values of the fire resistance limits of the two tested samples should not differ by more than 20% (from the larger value). If the results differ from each other by more than 20%, an additional test must be carried out, and the fire resistance limit is determined as the arithmetic mean of the two lower values.
In the designation of the fire resistance limit of a structure, the arithmetic mean of the test results is reduced to the nearest smaller value from the series of numbers given in.
The results obtained during testing can be used to evaluate the fire resistance of other similar (in shape, materials, design) structures using calculation methods.
12 TEST REPORT
The test report must contain the following data:
1) name of the organization conducting the test;
2) name of the customer;
3) the date and conditions of the test, and, if necessary, the date of manufacture of the samples;
4) name of the product, information about the manufacturer, trademark and marking of the sample indicating the technical documentation for the design;
5) designation of the standard for the test method of this design;
6) sketches and descriptions of tested samples, data on control measurements of the state of the samples, physical and mechanical properties of materials and their humidity;
7) conditions for supporting and fastening samples, information about butt joints;
8) for structures tested under load - information about the load adopted for testing and the loading scheme;
9) for asymmetrical structural samples - indication of the side subjected to thermal influence;
10) observations during testing (graphs, photographs, etc.), start and end times of the test;
11) processing of test results, their assessment, indicating the type and nature of the limit state and fire resistance limit;
12) validity period of the protocol.
Appendix A
(required)
SAFETY REQUIREMENTS FOR TESTING
1 Among the personnel servicing the test equipment there must be a person responsible for safety precautions.
2 When performing structural tests, it is necessary to ensure the availability of one 50 kg portable powder fire extinguisher, a portable CO2 extinguisher; fire hose with a diameter of at least 25 mm under pressure.
4 When testing structures, it is necessary to: determine a dangerous zone around the furnace of at least 1.5 m, into which unauthorized persons are prohibited from entering during testing; take measures to protect the health of persons conducting tests if destruction, overturning or cracking of the structure is expected as a result of the test (for example, installing supports, protective nets, etc.). Measures must also be taken to protect the structure of the oven itself.
5 The laboratory premises must have natural or mechanical ventilation that provides sufficient visibility in the working area for persons conducting tests and conditions for reliable work without breathing apparatus and thermal protective clothing during the entire test period.
6 If necessary, the area of the measuring and control station in the laboratory room must be protected from the penetration of flue gases by creating excess air pressure.
7 The fuel supply system must be equipped with light and/or audible alarm systems.
EXPLANATORY NOTE
to the project GOST 30247.0-94 "Building structures. Test methods for fire resistance. General requirements"
The development of the draft standard "Building structures. Test methods for fire resistance. General requirements" was carried out jointly by the TsNIISK named after. Kucherenko of the Ministry of Construction of the Russian Federation, VNIIPO of the Ministry of Internal Affairs of the Russian Federation and TsPITSS TsNIISK by order of the Ministry of Construction of the Russian Federation and is presented in the final version.
The expansion of trade and economic relations with foreign countries dictates the need to create a unified method for testing building structures for fire resistance, applicable in partner countries.
On an international scale, Technical Committee 92 of the International Organization for Standardization (ISO) is engaged in improving and unifying the methodology for testing building structures for fire resistance. Within the framework of this committee and on the basis of extensive international cooperation, a standard for the method of testing building structures for fire resistance ISO 834-75 has been developed, which is the methodological basis for conducting such tests.
Methods for testing building structures for fire resistance, used in the USA, Germany, France and other developed countries of the world, are also widely known.
In our country, tests of building structures for fire resistance are carried out in accordance with the previously developed SEV 1000-78 standard "Fire safety standards for building design. Method of testing building structures for fire resistance." Despite the undoubted merits of the standard at the time of its creation, at present some of its provisions needed to be clarified in order to bring them into compliance with the international standard ISO 834-75 and the achievements of domestic and foreign science in assessing the fire resistance of building structures.
When preparing the final version of the draft state standard, the main provisions of the international standard ISO 834-75, the draft ST SEV 1000-88, and the current standard ST SEV 1000-78 were adopted. The provisions contained in the national standards for fire tests BS 476-10, CSN 730-851, DIN 4102-2, etc. were also taken into account.
In addition, comments and suggestions on the previously received conclusions of various organizations (the Main Directorate of State fire service Ministry of Internal Affairs of the Russian Federation, NIIZHB, TsNIIPromizdanii, TsNIIEP housing and other organizations).
The developed draft standard is fundamental and includes general requirements for testing building structures for fire resistance, which take precedence over the requirements of standards for test methods for fire resistance of specific structures (load-bearing, fencing, doors and gates, air ducts, translucent structures, etc.) .
The standard is set out in accordance with the requirements of GOST 1.5 -92 " State system standardization of the Russian Federation. General requirements for the construction, presentation, design and content of standards."
GOST 30247.0-94
(ISO 834-75)
Group Zh39
INTERSTATE STANDARD
BUILDING STRUCTURES
FIRE RESISTANCE TEST METHODS
General requirements
Elementsofbuildingconstructions.Fire-resistancetestmethods.General requirements
ISS 13.220.50
OKSTU 5260
Date of introduction 1996-01-01
Preface
1 DEVELOPED by the State Central research and the Design and Experimental Institute of Complex Problems of Building Structures and Structures named after V.A. Kucherenko (TsNIISK named after Kucherenko) of the Ministry of Construction of Russia, the Center for Fire Research and Thermal Protection in Construction TsNIISK (CPITZS TsNIISK) and the All-Russian Research Institute of Fire Defense (VNIIPO) of the Ministry of Internal Affairs of Russia
INTRODUCED by the Ministry of Construction of Russia
2 ADOPTED by the Interstate Scientific and Technical Commission for Standardization and Technical Regulation in Construction (INTKS) on November 17, 1994.
Name of the state Name of the state construction management body
The Republic of Azerbaijan
Republic of Armenia
The Republic of Kazakhstan
Republic of Kyrgyzstan
The Republic of Moldova
Russian Federation
Republic of Tajikistan State Construction Committee of the Azerbaijan Republic
State Architecture of the Republic of Armenia
Ministry of Construction of the Republic of Kazakhstan
Gosstroy of the Kyrgyz Republic
Ministry of Architecture and Construction of the Republic of Moldova
Ministry of Construction of Russia
State Construction Committee of the Republic of Tajikistan
3 This standard is an authentic text of ISO 834-75 Fire resistance test - Elements of building constructions. “Fire resistance tests. Building construction"
ENTERED INTO EFFECT on January 1, 1996 as a state standard of the Russian Federation by Resolution of the Ministry of Construction of Russia dated March 23, 1995 No. 18-26
INSTEAD ST SEV 1000-78
REISSUE. May 2003
APPLICATION AREA
This standard regulates the general requirements for testing methods of building structures and elements of engineering systems (hereinafter referred to as structures) for fire resistance under standard conditions of thermal exposure and is used to establish fire resistance limits.
The standard is fundamental in relation to standards for fire resistance testing methods for specific types of structures.
When establishing the fire resistance limits of structures in order to determine the possibility of their use in accordance with the fire safety requirements of regulatory documents (including certification), the methods established by this standard should be used.
DEFINITIONS
The following terms are used in this standard.
Fire resistance of the structure: According to GOST 12.1.033.
Fire resistance limit of the structure: According to GOST 12.1.033.
3 limiting state of a structure for fire resistance: The state of a structure in which it loses the ability to maintain load-bearing and/or enclosing functions in fire conditions.
ESSENCE OF TEST METHODS
The essence of the methods is to determine the time from the beginning of thermal impact on the structure, in accordance with this standard, until the onset of one or successively several limit states for fire resistance, taking into account the functional purpose of the structure.
STAND EQUIPMENT
Stand equipment includes:
Test furnaces with a fuel supply and combustion system (hereinafter referred to as furnaces);
Devices for installing the sample on the furnace, ensuring compliance with the conditions of its fastening and loading;
Systems for measuring and recording parameters, including equipment for filming, photography or video recording.
Furnaces must provide the ability to test structural samples under the required conditions of loading, support, temperature and pressure specified in this standard and in the standards for testing methods for specific types of structures.
The main dimensions of furnace openings must be such as to ensure the possibility of testing samples of structures of designed sizes.
If it is not possible to test samples of design sizes, their dimensions and furnace openings must be such as to ensure the conditions of thermal exposure to the sample, regulated by standards for fire resistance testing methods for specific types of structures.
The depth of the fire chamber of furnaces must be at least 0.8 m.
The design of the furnace masonry, including its outer surface, must provide the possibility of installing and fastening the sample, equipment and fixtures.
The temperature in the furnace and its deviations during the test must comply with the requirements of section 6.
The temperature regime of the furnaces must be ensured by burning liquid fuel or gas.
The combustion system must be adjustable.
The burner flame should not touch the surface of the structures being tested.
When testing structures whose fire resistance limit is determined by the limit states specified in 9.1.2 and 9.1.3, excess pressure must be ensured in the fire space of the furnace.
It is allowed not to control excess pressure when testing the fire resistance of load-bearing rod structures (columns, beams, trusses, etc.), as well as in cases where its influence on the fire resistance limit of the structure is insignificant (reinforced concrete, stone, etc. structures).
5.3 Furnaces for testing load-bearing structures must be equipped with loading and support devices that ensure loading of the sample in accordance with its design diagram.
Requirements for measurement systems
During testing, the following parameters should be measured and recorded:
Parameters of the environment in the fire chamber of the furnace - temperature and pressure (taking into account 5.2.8);
Loading and deformation parameters when testing load-bearing structures.
The temperature of the medium in the fire chamber of the furnace must be measured by thermoelectric converters (thermocouples) in at least five
Places. In this case, for every 1.5 m of the opening of the furnace intended for testing enclosing structures, and for every 0.5 m of the length (or height) of the furnace intended for testing rod structures, there must be
At least one thermocouple is installed.
The soldered end of the thermocouple should be installed at a distance of 100 mm from the surface of the calibration sample.
The distance from the soldered end of the thermocouples to the furnace walls must be at least 200 mm.
The temperature in the furnace is measured by thermocouples with electrodes with a diameter of 0.75 to 3.2 mm. The hot junction of the electrodes must be free. The protective casing (cylinder) of the thermocouple must be removed (cut and removed) at a length of (25±10) mm from its soldered end.
To measure the temperature of samples, including on the unheated surface of enclosing structures, thermocouples with electrodes with a diameter of no more than 0.75 mm are used.
The method of attaching thermocouples to the test sample of the structure must ensure the accuracy of measuring the temperature of the sample within the limits
In addition, to determine the temperature at any point on the unheated surface of the structure where the greatest increase in temperature is expected, it is allowed to use a portable thermocouple equipped with a holder or other technical means.
The use of thermocouples with a protective casing or with electrodes of other diameters is permitted, provided that their sensitivity is not lower and the time constant is not higher than that of thermocouples made in accordance with 5.4.3 and 5.4.4.
To record measured temperatures, instruments of at least accuracy class 1 should be used.
Instruments designed to measure pressure in a furnace and record the results must provide a measurement accuracy of ±2.0 Pa.
Measuring instruments must provide continuous recording or discrete recording of parameters with an interval of no more than 60 s.
To determine the loss of integrity of enclosing structures, use a cotton or natural wool swab.
The dimensions of the tampon should be 100-10030 mm, weight - from 3 to 4 g. Before use, the tampon is kept in a drying cabinet at a temperature of (105±5)°C for 24 hours. The swab is removed from the drying oven no earlier than 30 minutes before the start of the test. Repeated use of a tampon is not allowed.
Calibration of bench equipment
Calibration of furnaces involves monitoring the temperature and pressure in the furnace volume. In this case, a calibration sample is placed in the opening of the furnace for testing structures.
The design of the calibration sample must have a fire resistance rating no less than the calibration time.
The calibration sample for furnaces intended for testing enclosing structures must be made of a reinforced concrete slab with a thickness of at least 150 mm.
The calibration sample for furnaces intended for testing rod structures must be made in the form of a reinforced concrete column with a height of at least 2.5 m and a cross-section of at least 0.04 m.
Calibration duration is at least 90 minutes.
TEMPERATURE REGIME
During testing and calibration in furnaces, a standard temperature regime must be created, characterized by the following relationship:
Where T is the temperature in the furnace corresponding to time t, °C;
Temperature in the furnace before the start of thermal exposure (taken to be equal to the ambient temperature), °C;
T - time calculated from the beginning of the test, min.
If necessary, a different temperature regime can be created, taking into account real fire conditions.
The deviation H of the average measured temperature in the furnace (5.4.2) from the value T calculated using formula (1) is determined as a percentage using the formula
The average measured temperature in the furnace is taken to be the arithmetic mean of the readings of the furnace thermocouples at time t.
The temperatures corresponding to dependence (1), as well as the permissible deviations from them of the average measured temperatures are given in Table 1.
Table 1
T, min, °С Permissible deviation value H, %
10,659 15,718 ±10
30,821 45,875 ±5
60 925 90 986 120 1029 150 1060 180 1090 240 1133 360 1193 When testing structures made of non-combustible materials on individual furnace thermocouples, after 10 minutes of testing, the temperature deviation from the standard temperature regime is allowed by no more than 100 ° C.
For other designs, such deviations should not exceed 200°C.
SAMPLES FOR TESTING STRUCTURES
Samples for testing structures must have design dimensions. If it is not possible to test samples of such sizes, then the minimum sample sizes are taken according to the standards for testing structures of the corresponding types, taking into account 5.2.2.
Materials and parts of samples to be tested, including butt joints of walls, partitions, ceilings, coatings and other structures, must comply with the technical documentation for their manufacture and use.
At the request of the testing laboratory, the properties of construction materials are, if necessary, controlled on their standard samples, manufactured specifically for this purpose from the same materials simultaneously with the manufacture of structures. Before testing, control standard samples of materials must be in the same conditions as experimental samples of structures, and their tests are carried out in accordance with current standards.
The humidity of the sample must comply with the specifications and be dynamically balanced with the environment with a relative humidity of (60±15)% at a temperature of (20±10)°C.
The moisture content of the sample is determined directly on the sample or on a representative part of it.
To obtain dynamically balanced humidity, natural or artificial drying of samples is allowed at an air temperature not exceeding 60°C.
To test a structure of the same type, two identical samples must be made.
The samples must be accompanied by the necessary set of technical documentation.
When conducting certification tests, samples must be taken in accordance with the requirements of the adopted certification scheme.
TESTING
Tests are carried out at ambient temperatures from 1 to 40°C and at an air speed of no more than 0.5 m/s, unless the conditions of use of the structure require other test conditions.
The ambient temperature is measured at a distance no closer than 1 m from the surface of the sample.
The temperature in the oven and in the room must be stabilized 2 hours before the start of testing.
During the test the following is recorded:
Time of occurrence of limiting states and their type (section 9);
Temperature in the oven, on the unheated surface of the structure, as well as in other pre-installed places;
Excessive pressure in the furnace when testing structures whose fire resistance is determined by the limit states specified in 9.1.2 and 9.1.3;
Deformations of load-bearing structures;
Time of flame appearance on the unheated surface of the sample;
The time of appearance and the nature of cracks, holes, peelings, as well as other phenomena (for example, violation of support conditions, the appearance of smoke).
The given list of measured parameters and recorded phenomena can be supplemented and changed in accordance with the requirements of test methods for specific types of structures.
The test must continue until the occurrence of one or, if possible, sequentially all limit states standardized for a given design.
LIMIT STATES
The following main types of limit states of building structures for fire resistance are distinguished.
Loss of load-bearing capacity due to collapse of the structure or the occurrence of extreme deformations (R).
Loss of integrity as a result of the formation of through cracks or holes in structures through which combustion products or flames penetrate onto an unheated surface (E).
Loss of thermal insulation ability due to an increase in temperature on the unheated surface of the structure to the maximum values for a given structure (I).
9.2 Additional limit states of structures and criteria for their occurrence, if necessary, are established in the standards for testing specific structures.
DESIGNATIONS FOR FIRE RESISTANCE LIMITS OF STRUCTURES
The designation of the fire resistance limit of a building structure consists of symbols of the limit states normalized for a given structure (see 9.1) and a number corresponding to the time to achieve one of these states (the first in time) in minutes.
For example:
R 120 - fire resistance limit 120 min - for loss of load-bearing capacity;
RE 60 - fire resistance limit 60 min - for loss of load-bearing capacity and loss of integrity, regardless of which of the two limit states occurs earlier;
REI 30 - fire resistance limit 30 min - for loss of load-bearing capacity, integrity and thermal insulation capacity, regardless of which of the three limit states occurs earlier.
When drawing up a test report and issuing a certificate, the limit state for which the fire resistance limit of the structure is established should be indicated.
If different fire resistance limits are standardized (or established) for a structure for different limit states, the designation of the fire resistance limit consists of two or three parts, separated by a slash.
For example:
R 120 / EI 60 - fire resistance limit 120 min - for loss of load-bearing capacity; fire resistance limit 60 minutes - for loss of integrity or thermal insulation ability, regardless of which of the last two limit states occurs earlier.
For different values of fire resistance limits of the same structure for different limit states, fire resistance limits are designated in descending order.
The digital indicator in the designation of the fire resistance limit must correspond to one of the numbers in the following series: 15, 30, 45, 60, 90, 120,
150, 180, 240, 360.
EVALUATION OF TEST RESULTS
The fire resistance limit of a structure (in minutes) is determined as the arithmetic average of the test results of two samples. In this case, the maximum and minimum values of the fire resistance limits of the two tested samples should not differ by more than 20% (from the larger value). If the results differ from each other by more than 20%, an additional test must be carried out, and the fire resistance limit is determined as the arithmetic mean of the two lower values.
In designating the fire resistance limit of a structure, the arithmetic average of the test results is reduced to the nearest smaller value from the series of numbers given in Section 10.
The results obtained during testing can be used to evaluate the fire resistance using calculation methods of other similar (in shape, materials, design) structures.
TEST REPORT
The test report must contain the following data:
Name of the organization conducting the test;
Customer's name;
The date and conditions of the test, and, if necessary, the date of manufacture of the samples;
Product name, information about the manufacturer, trademark and sample marking indicating the technical documentation for the design;
Designation of the standard for the test method of this design;
Sketches and descriptions of tested samples, data on control measurements of the state of the samples, physical and mechanical properties of materials and their humidity;
Conditions for supporting and fastening samples, information about butt joints;
For structures tested under load - information about the load accepted for testing and loading patterns;
For asymmetrical structural samples - indication of the side subjected to thermal influence;
Observations during the test (graphs, photographs, etc.), start and end times of the test;
11) processing of test results, their assessment, indicating the type and nature of the limit state and fire resistance limit;
12) validity period of the protocol.
Appendix A (mandatory). SAFETY REQUIREMENTS FOR TESTING
Appendix A (mandatory)
1 Among the personnel servicing the test equipment there must be a person responsible for safety precautions.
When performing structural testing, one 50 kg portable dry powder fire extinguisher, portable CO extinguisher should be provided; fire hose with a diameter of at least 25 mm under pressure.
It is prohibited to pour water on the lining of the furnace fire chamber.
When testing structures, it is necessary to: determine the dangerous zone around the furnace of at least 1.5 m, into which unauthorized persons are prohibited from entering during testing; take measures to protect the health of persons conducting tests if destruction, overturning or cracking of the structure is expected as a result of the test (for example, installing supports, protective nets). Measures must be taken to protect the structures of the furnace itself.
The laboratory premises must have natural or mechanical ventilation that provides sufficient visibility in the working area for persons conducting tests and conditions for reliable work without breathing apparatus and thermal protective clothing during the entire test period.
If necessary, the area of the measuring and control post in the laboratory must be protected from the penetration of flue gases by creating excess air pressure.
The fuel supply system must be equipped with light and/or audible alarm systems.
UDC 624.001.4:006.354MKS 13.220.50Zh39OKSTU 5260
Key words: fire resistance, fire resistance limit, building structures, general requirements
