GB/T 2918-1998 Standard environment for conditioning and testing of plastic specimens
Some standard content:
1CS 83. 040. 01
National Standard of the People's Republic of China
CB/T2918-1998
idt ISO 291:1997
Plastics--Standard atmospheresfor conditioning and testing1998-10-19 Issued
1999-04-01 Implementation
State Administration of Quality and Technical Supervision Issued
GB/T 29181998
This standard adopts the national standard 02197 Plastics-Standard atmospheres for conditioning and testing. Except for some editorial corrections in accordance with national conditions, this standard is consistent with 150291:1997 in terms of technical content and writing methods! 997, the previous version of this standard is GB/T2918.-1982 Standard environment for plastic specimens and tests 3. Compared with the previous version, the main technical parameters have changed,
1. Only one standard environment (23/50) is specified. Now two standard environments (23/50, 27/65) are specified. 3. The tolerance of temperature and relative humidity, which only considers the deviation over time, is changed to consider the deviation over time, and also considers the difference of the sample in the comparison environment,
3. The tolerance of relative humidity is changed from ±2% to ±5%, and the tolerance of humidity is changed from ±5% to ±10%, 4. Close! The "abstract" and "room temperature" in the two environmental terms of random temperature requirements are changed from "within reason", that is, 45%--75% to uncontrolled relative humidity,
5. Change "normal pursuit" to "room requirement", and change its range of 10℃35 to 18℃~28℃. 6. For the normal cycle: the standard adds the provision of "for the room temperature environment of 18~, not less than h\", and the standard adds "international standard environment\30 term definitions", "principles" and appendices, etc. This standard is effective from the date of implementation. G1291-1962 This standard is the appendix of the international standard and Appendix B is the male standard. The author of this standard is: the Chemical Industry Department of China proposed this standard: the Plastics Technical Committee of the Plastics Branch (SC1). The sponsor of this standard is the Beijing Institute of Chemical Engineering of the Ministry of Industry. The co-drafting units of this standard are Sichuan Union University, Beijing Aviation Materials Research Institute, Beijing Plastics Research Institute, and the main drafter of this standard is Xia Yongming.
This standard was first issued on March 2, 1982, GB/T2918—1998
ISO Foreword
International Organization for Standardization (ISO) The work of formulating international standards is usually carried out by a technical committee. Any member body that is interested in a technical issue determined by the ISO has the right to request the establishment of a technical committee. Governmental and non-governmental standard-setting organizations may also participate in the work of ISO. ISO works closely with the International Electrotechnical Commission (IEC) on all subjects of electrotechnical standardization. The draft national standards adopted by the technical committee are circulated to member bodies for voting before being accepted as international standards by the ISO Council. The second edition of this standard replaces the first edition of the standard 15 TC.291:19773, which has been technically revised. Appendix A is the former part of this international standard, and Appendix B is only a citation appendix. 1 Scope wwW.bzxz.Net
National Standard of the People's Republic of China
Standard environment for plastic specimen conditioning and testing
Piastics-Standard atmospheresforconditioningandtesting
GB/T 2918—19SB
ID11so291:1997
This standard proposes the specifications for various plastics and similar test pieces to be subjected to condition conditioning and testing under certain environmental conditions equivalent to those allowed in a laboratory.
This standard does not include the special environment for certain special test materials or test pieces with certain atmospheres. 2 Definitions
This standard applies to the following definitions.
2.1 Standard environment The standard environment refers to the preferred environment that specifies the air quality, humidity, atmospheric pressure and air circulation range. The research atmosphere does not contain obvious foreign components and the environmental damage is not significantly affected by any external radiation. 1 Standard environment card The product can reach the specified state. 2.2 Conditioning environment\orditioninratmusphere is a system of conditions in which the test product is stored in a certain environment. 2.3 Test environment testatnnapheze
The constant environment in which the test product is placed during the entire test period. 2.4 Conditioning
One or more operations performed to make the sample or specimen reach the specified temperature and humidity. 2.5 Conditioning procedure canditiening procedure is a combination of condition conditioning environment and natural condition conditioning cycle. Method 3: In this standard, the standard environment is usually selected as the condition conditioning environment and the method is not dangerous. 2.6 Room temperature ambienrtemp erarat
It is equivalent to an environment with controlled temperature and humidity, and the degree of the environment must be blocked by the general atmospheric conditions. 3 Principle
If the sample is placed in a specified state-conditioned environment or temperature, then a reproducible state of humidity and/or concentration equilibrium can be achieved between the sample and the state-conditioned environment or temperature. Approved by the State Administration of Quality and Technical Supervision on 8-10-19, 1999-04-01 for implementation
4 Standard environment
/2918-1998
Unless otherwise specified, the conditions given in the standard environment shall be used as the standard environment. 1 Standard environment
Protective environment
Air resistance
Board is good
The order should be the same as the production environment, unless
Unless otherwise specified
For the next area, it is agreed,||tt ||Can be used
Note 4: The position in the first paragraph is applicable to the occasions where the atmospheric strength is between the standard P and the center kF% - the whole stop inspection height and the air volume opening speed: 1l/9, the same as the standard environment
Table 2 gives two different cable standards for standard environments, corresponding to the temperature and the strength tolerance (i.e., the allowable) level. The tolerances given in Table 2 are applicable to the test environment, the state adjustment environment, the test license, the air conditioner, the test license, the time and the position of the sample in the environment. The actual deviation:
Table 2 corresponds to the standard bad night temperature and the allowable deviation of the total
2 (generally)
Base on the allowable deviation
5, the 1 tolerance or tolerance of the matching skin is extended for the standard environment and the room temperature
The result is not very good for the general performance If the influence or the combined influence can be ignored, then there is no need to control the double flow. The two environments are called "humidity 25" and "temperature 27". Similarly, if neither temperature nor humidity has any significant effect on the measured performance, then neither temperature nor relative humidity needs to be controlled. In this case, the environment is called "applied temperature". "Room temperature" refers to an environment where the air temperature is kept within the specified range without considering the influence of relative humidity, atmospheric pressure or air circulation. Usually, the air temperature range is 1628℃, which should be called "room limit of 18~-28℃". 7 Procedures. 1 Conditioning The condition conditioning cycle should be specified in the relevant standards of the material. When the condition conditioning period is specified in the corresponding standard, the above period should be used:) For standard environments 23/50 and 27/65,Not less than 38h: h) for 18~28 milliseconds, not less than 4h,
Lan 6, for the test and known ability to quickly and slowly reach the desired humidity of the sample, the short or long period of time can be determined in the same way as the test sample (see Note A). Test
GH/T 291B—1998
Unless otherwise specified, the sample after conditioning should be tested in the same environment or temperature as the conditioning. In any case, the test should be carried out immediately after the sample is taken out of the conditioning environment. CB/T2918--1998
Appendix A
(Standard Appendix Requirements)
Before the sample is conditioned in a certain environment, its hygroscopicity and the rate of absorption or desorption of moisture depend significantly on the characteristics and shape of the material used to make the sample. The conditioning time given in .1 may not be applicable, especially for the following situations: - It is known that the material can only reach equilibrium with the conditioning environment after a long time (such as amides) - Its absorption capacity is different from the time required to reach equilibrium. For unripe materials which cannot be prepared in advance, the following methods may be used: 1) subjecting the material to an elevated temperature which will not cause appreciable or permanent changes in the material (for most materials an acceptable temperature is 0 ± 23 °C for many hours) until equilibrium is reached; 2) subjecting the specimens to a specified elevated temperature in a high-efficiency air drying oven or conditioner until equilibrium is reached (the concentration and relative health should be determined by the parties concerned and should be reported in the test report). Method 1 has the disadvantage that some comparative energy measurements, especially those for scientific energy values, may differ from those obtained after conditioning in the standard environment at 23 °C.
For Method 6, the following rule of thumb may be useful: If the variation of the results obtained over a period of 1 week is not greater than 0.1%, it can be assumed that equilibrium has been reached (where 4 is the test length in mm). If the moisture expansion properties of the polymer are known and can be used to confirm compliance with the intended use period and conditions, Method c can be used. The sample should be placed in an oven or conditioning oven until it is in a state of moisture content equilibrium. If the average moisture content of the material during the conditioning period is less than 0.01%, that is, To reach this state, the following criteria are used to estimate the time to reach the equilibrium: If the diffusion coefficient D is known, the time to reach the equilibrium becomes C.324/D or 1 day, whichever is greater (a is the test thickness in mm: is the state adjustment time in mm). Appendix B
(Supplementary information)
H1 Overview
1S02S1:1997 Preliminary IS29:1977 is based on S0/C125 S554.197 state section and/or test environment - the standard is based on the specification, 50201:1977 can no longer represent the current technical level. Some of the terms used are outdated, for example: - a pair of uncontrolled humidity inspection environment, such as environment 23. Easy to compare with standard environment 22/50 (humidity needs to be controlled> relative slip: the tolerance of temperature and humidity can include the actual difference over time: the relative tolerance of all degrees is lower than the theoretically possible value, for example, the relative tolerance of the time training constant of the step and peeling meter is set to ± 5%. The relative humidity difference of B2
The wider tolerance given in this standard includes the deviations with time and with the test environment. +
GB/T291B-1998
Table 2 shows the relative humidity difference of B2, which is the minimum humidity that can be achieved theoretically under a given temperature tolerance (i.e. if the allowable humidity difference is ±0.04°C, the relative humidity difference given in 292:1977 should be less than 19. The relative humidity range is given by the following formula: ? = K. - 4 + K.. -tJ
In the play: Ar..Air temperature tolerance:
4—demand point temperature tolerance,
K,-—air temperature coefficient;
K, end point elevation coefficient,
For example, when =, the relative tolerance of the relative sensitivity
Standard environment 23/50, 2 levels of difference:
=3,3X2.053.30×0.96.06%
A standard environment 27/65, 2 levels of penetration,
3.82x1.0+3.76xt.03.8 2%
Wherein: 3.03——K value of standard open environment 23/50: 3.30——K value of standard environment 23/50
3.82——K value of standard environment 27/65
3.76——K value of standard environment 27/5, therefore, the actual current point has to be determined. The relative humidity tolerance of the standard environment should be set as +10 (for the standard environment type, it is set as +5), which includes:
actual tolerance of dew point
general recognition error and drift tolerance of control device and virtual meter,06%
a standard environment 27/65, 2nd level,
3.82x1.0+3.76xt.03.82%
wherein: 3.03——K value of standard open environment 23/50: 3.30K value of standard environment 23/50
3.82—K value of standard environment 27/65
3.76—K value of standard environment 27/5, therefore, the actual current point has to be determined, and the relative humidity tolerance of the standard environment should be set as +10 (for the standard environment type, it is set as ±5), which includes:
the actual tolerance of the dew point
the general recognition error and drift tolerance of the control device and the virtual meter,06%
a standard environment 27/65, 2nd level,
3.82x1.0+3.76xt.03.82%
wherein: 3.03——K value of standard open environment 23/50: 3.30K value of standard environment 23/50
3.82—K value of standard environment 27/65
3.76—K value of standard environment 27/5, therefore, the actual current point has to come, the relative humidity tolerance of 2 standard environment should be set as +10 (for 1st level standard environment type, it is set as ±5), which includes:
actual tolerance of dew point
general recognition error and drift tolerance of control device and virtual meter,
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