GB/T 8625-2005 PDF in English
GB/T 8625-2005 (GB/T8625-2005, GBT 8625-2005, GBT8625-2005)
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GB/T 8625-2005 | English | 70 |
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Test method of difficult-flammability for building materials
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GB/T 8625-1988 | English | 359 |
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Test method of difficult-flammability for building materials
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Standards related to (historical): GB/T 8625-2005
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GB/T 8625-2005: PDF in English (GBT 8625-2005) GB/T 8625-2005
GB
ICS 13.220.50
Q 10
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
Replacing GB/T 8625-1988
Test Method of Difficult-Flammability for
Building Materials
ISSUED ON. JULY 15, 2005
IMPLEMENTED ON. JANUARY 01, 2006
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine of the People's Republic of China;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Test Apparatus ... 4
4 Test-piece Preparation ... 7
5 Coupon and sample preparation ... 8
6 Judgment of Residue Length after Test-piece Combustion ... 9
7 Judgment Rules ... 9
8 Test Report ... 10
Foreword
This Standard is not equivalent to DIN 4102-1.1998 "Fire Behaviour of Building
Materials and Building Components - Part 1. Building Materials; Concepts,
Requirements and Tests", DIN 4102-15.1990 "Fire Behaviour of Building Materials
and Elements Brandschacht" and DlN 4102-16.1998 "Fire Behaviour of Building
Materials and Building Components - Part 16. 'Brandschacht' Tests".
This Standard replaces GB/T 8625-1988 "Test Method of Difficult-Flammability for
Building Materials".
Compared with GB/T 8625-1988, this Standard has the following main changes.
- For test devices, ADD the test device for furnace pressure and the calibration
and inspection for vertical furnace, and ADJUST the controlling conditions of
furnace wall temperature according to the requirements of DIN 4102-15.1990;
- In the test, the calculation and test procedures for fuel gas and air flow were
conducted by microcomputer;
- The fuel gas adopted the methane gas with purity of 95% in order to adapt to
conditions in China.
This Standard was proposed by the Ministry of Public Security of the People's
Republic of China.
This Standard is under the jurisdiction of the Seventh Technical Subcommittee of
National Technical Committee on Fire Protection of Standardization Administration of
China.
Drafting organization of this Standard. Sichuan Fire Research Institute of Ministry of
Public Security.
Main drafters of this Standard. Ding Min and Chen Genbao.
The previous edition of the standard replaced by this Standard is.
- G8/T 8625-1988.
Test Method of Difficult-Flammability for Building Materials
1 Scope
This Standard specifies the test apparatus, test-piece preparation, test operation,
judgment of the residue length after test-piece combustion, judgment criteria and test
report of difficult-flammability test for building materials.
This Standard is applicable to the determination of difficult-flammability for building
materials.
2 Normative references
The provisions in following documents become the provisions of this Standard
through reference in this Standard. For dated references, the subsequent
amendments (excluding corrigendum) or revisions do not apply to this Standard,
however, parties who reach an agreement based on this Standard are encouraged to
study if the latest versions of these documents are applicable. For undated references,
the latest edition of the referenced document applies.
GB 8624-1997 Classification for Burning Behavior of Building Materials
GB/T 8626-1988 Test Method of Flammability for Building Materials
GB/T 8627-1999 Test Method for Density of Smoke from the Burning or
Decomposition of Building Materials
3 Test Apparatus
The test apparatus of this method mainly include the combustion vertical furnace and
test equipment.
3.1 Combustion vertical chamber
The combustion vertical furnace mainly comprises the combustion chamber, burner,
test-piece support, air steady-state flow layer, gas flue and other parts. The overall
dimension is 1700mm×1020mm×3930mm (see Figure 1 and Figure 2).
3.1.1 Combustion chamber
thermocouple, temperature recorder, temperature display instrument and furnace
pressure test instruments.
3.2.1 Flowmeter
For the determination of methane gas and compressed air flow, the flowmeter shall be
selected with precision of Class 2.5 and measuring range of (0.25~2.5) m3/h.
3.2.2 Thermocouple
For the determination of flue gas temperature and furnace wall temperature, the
nickel-chromium-alloy armoured thermocouple with precision of Class II, wire
diameter of 0.5mm and external diameter no larger than 3mm shall be adopted. The
installation positions are detailed in Figure 2.
3.2.3 Temperature recorder and display instrument
For temperature measurement, it may adopt microcomputer for indication and record
and the measuring accuracy is 1°C; it may also adopt continuous recording electronic
potential difference gauge or other suitable continuous recording instrument, which is
of Class 0.5 precision and matched with the thermocouple.
3.3 Furnace pressure
Install a T-shaped furnace pressure test pipe at the gas flue position that is 2700mm
away from the furnace bottom and 100mm away from the gas flue wall. The inner
diameter of the T-shaped pipe is 10mm and the head width is 100mm. It is connected
with the microcomputer or other recorders through one set of differential pressure
transmitter of Class 0.5 precision. In this way, it is monitored continuously.
3.4 Calibration tests on components in combustion vertical furnace
3.4.1 Uniformity test on thermal load
In order to ensure that the test-piece is able to bear the uniformity of the thermal load
in the test, the following steps shall be followed. place 4 stainless steel plates of
1000mm×190mm×3mm on the test-piece support and set 1 nickel-chromium-alloy
thermocouple soundly on the center line of the place where is 200mm away from each
bottom of the stainless steel plate respectively. The test shall be carried out according
to the procedure specified in Chapter 5. After the test is conducted for 10min, the
temperature mean measured from above-mentioned four thermocouples on the
stainless steel plates shall be 540°C±15°C; otherwise, the equipment shall be
debugged. This test must be carried out once every three months.
interval is 24h and the variation rate of the mass measured in two times shall not be
larger than 0.1%. If the equilibrium state can not be determined through weighing,
then it shall be stored for 28d in above-mentioned temperature and humidity
conditions before the test.
5 Coupon and sample preparation
5.1 The test shall be carried out in the combustion vertical furnace as shown in Figure
1 .
5.2 FIX 4 samples, which meets those specified in 4.2 after state regulation, to the
test-piece support vertically to constitute a vertical square flue. The relative distance
of samples shall be (250±2) mm.
5.3 The furnace pressure shall be kept at (-15±10) Pa.
5.4 Before putting the test-pieces into the combustion chamber, the temperature of
the inner furnace wall of the vertical furnace shall be preheated to 50°C.
5.5 The test-piece shall be put at the specified position in the combustion chamber
and the furnace door shall be closed.
5.6 Where the furnace wall temperature falls to (40±5)°C, ignite the burner, meanwhile,
press the timer button and start the test. In the test, the air flow in the vertical furnace
shall be with flow of (10±1) m3/min and at temperature of (23±2)°C. The fuel gas used
in the burner shall be the gas mixture of methane and air; the methane flow shall be
(35±0.5) L/min and its purity shall be larger than 95%; the air flow shall be (17.5±0.2)
L/min. The above two gas flow shall be calculated according to the normal state.
The calculation formula for the gas in normal state shall be.
tt
00
VP
VP
Where.
P0 - 101325 Pa;
V0 - 35L/min for methane gas and 17.5L/min for air;
T0 - 273°C;
Pt - the ambient atmospheric pressure plus the inlet pressure for the fuel gas to
enter in the flowmeter, expressed in Pascal (Pa);
required in GB 8624-1997 may be defined as building materials of
difficult-flammability.
8 Test Report
The test report shall include the following contents.
a) Test criteria;
b) Building material name, model and specification, production organization name
and address as well as production date;
c) For wood and fabric used fire retardant, the test-piece appearance after
brushing fire retardant shall be explained and the dry and wet brushing
quantity (g/kg or g/m2) of the used fire retard shall be noted;
d) General description of samples, including the trademark (or marking) and the
structure form of the sample;
e) Minimum residue length and average residue length of the test-piece after
burning;
f) Maximum value of average flue gas temperature of test-piece;
g) Phenomena observation. including the sample burning condition, the sample
smoldering and the sustained burning of the dripped object on the screen
mesh;
h) Test date.
...... Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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