There are standards and subsidies, but according to national regulations, only high-power communication equipment in special industries may exceed standards.
(According to national standards, communication base stations with communication distances greater than 40 kilometers may enjoy subsidies if they exceed the standard. Mobile phone base stations in cities do not exceed the standard. If converted into ordinary equipment, 3,000 mobile phones must be used at the same time. LCD 1.5W monitors must be turned on at the same time to exceed the standard)
National Standard of the People's Republic of China
GB 12638-90
Microwave and ultra-short wave communications Equipment radiation safety requirements
Safety requirement of radiation for microwave and
ultrashort wave communication equipment
1 Subject content and scope of application
This The standard stipulates the radiation intensity limit that can ensure the safety of occupationally exposed personnel within a certain distance from microwave and ultra-short wave communication equipment.
This standard applies to the radiation safety requirements for the environment and areas where check-in operators at each working position are located when microwave and ultra-short wave communication equipment is working.
2 Reference standards
GJB 7 Microwave radiation safety limits
3 Terminology
3.1 Microwave
Microwave refers to electromagnetic waves with a frequency of 300MHz-300GHz and a corresponding wavelength range of 1m-1mm.
3.2 Ultrashort wave
Ultrashort wave refers to the electromagnetic wave with a frequency of 30-300MHz and a corresponding wavelength in the range of 10-1m.
3.3 Communication equipment
Equipment for transmitting, receiving, converting, transmitting and displaying information.
3.4 Microwave Radiation
Microwave `Ultra-short wave communication equipment radiates microwave energy to the surrounding space through various channels, which is called microwave radiation.
3.5 Average power density
The average radiant power per unit area of incident microwave, the commonly used measurement unit is microwatt/cm or milliwatt/cm
(μW/cm or mW/cm).
3.6 Daily dose
The total daily dose of microwave radiation received per unit area is equal to the product of the average power density and the exposure time. Commonly used units are
Microwatt hour/centimeter (μW·h/cm) or milliwatt hour/centimeter (mW·h/cm).
3.7 Pulse wave and continuous wave
When microwave and ultra-short wave equipment is working, the microwave signal using pulse modulation is referred to as pulse wave, and the unmodulated continuous oscillating microwave signal is referred to as Continuous wave.
3.8 Continuous exposure and intermittent exposure
If the check-in operators of microwave and ultra-short wave communication equipment are continuously exposed to microwave radiation, it is called continuous exposure; if they are intermittently exposed to microwave radiation, it is called intermittent exposure. .
3.9 Exposure time
The time the check-in operator is exposed to microwave radiation. The common unit of measurement is hour (h).
4 Radiation safety requirements for microwave communication equipment
4.1 Regulations on the allowable average power density of microwave radiation at each working position of check-in operators.
4.1.1 Pulse wave
a. When exposed continuously for eight hours a day. The allowable average power density is 25μW/cm.
b. When exposed intermittently for a short period of time or for more than eight hours a day, the daily dose shall not exceed 200 μW·h/cm.
c. When exposed to an environment with an average power density greater than 25μW/cm or a daily dose exceeding 200μW·h/cm, corresponding protective measures should be taken (such as wearing microwave goggles, microwave bodysuit, and regular physical examinations and higher nutritional guarantee).
d. The upper limit of the average power density allowed for exposure is 2 mW/cm.
4.1.2 Continuous wave
a. When exposed continuously for eight hours a day. The allowable average power density is 50μW/cm.
b. When exposed intermittently for a short period of time or for more than eight hours a day, the daily dose shall not exceed 400 μW·h/cm.
c. When exposed to an environment with an average power density greater than 50μW/cm or a daily dose exceeding 400μW·h/cm, corresponding protective measures should be taken (such as wearing microwave goggles, microwave bodysuit, and regular physical examinations and higher nutrition guarantees).
e. The upper limit of the average power density allowed for exposure is 4 mW/cm.
4.2 Microwave radiation safety limit expression
4.2.1 Pulse wave
Pd= (1)
(0.1 Pd=2000(t≤0.1) Pd=25(t≥8) In the formula: Pd-average power density, μW /cm t——Daily exposure time, h. 4.2.2 Continuous wave Pd= (2) (0.1＜t＜8) Pd=4000(t ≤0.1) Pd=50 (t≥8) Where: Pd - average power density, μW/cm t - daily exposure time ,h. 4.3 Radiation safety requirements for microwave communication equipment See Appendix A (Supplement) for details 5 Radiation safety requirements for ultra-short wave communication equipment 5.1 Pulse wave 5.1.1 When exposed continuously for eight hours a day, the allowable average electric field strength is 10V/m. 5.1.2 The upper limit of the average electric field strength allowed for exposure is 90V/m. 5.2 Continuous wave 5.2.1 When exposed continuously for eight hours a day, the allowable average electric field strength is 14V/m. 5.2.2 The upper limit of the average electric field intensity allowed to be exposed is 123V/m. 5.2.3 For details on the conversion of average electric field strength in the ultrashort wave band, see Appendix C (reference part). 5.3 Measurement conditions for ultrashort wave communication equipment radiation See Appendix B (Supplement) for details. Appendix A Microwave communication equipment radiation measurement conditions (Supplement) A1 Scope of application This appendix is applicable to microwave radiation measurements of various types of microwave communication equipment in the frequency range of 300-3000000MHz, and is applicable to both continuous waves and pulse waves. A2 content Includes requirements for measuring instruments and measurement principles and methods. A2.1 Measuring instruments At present, due to various conditions, until unified standard measuring instruments are not promulgated, the measuring instruments required to be used should be tested by the standard field method and the standard antenna method. Two microwave radiation measurement devices with consistent calibration. Calibration of measuring instruments: Measuring instruments should be periodically calibrated according to prescribed procedures. A2.2 Unit of measurement The unit of measurement of microwave radiation is expressed in power density (i.e. μW/cm or mW/cm). The cumulative dose of microwave radiation (referring to radiation for more than eight hours or intermittent radiation for a short period of time, adopted when the radiation intensity changes randomly) is expressed in units of energy density (i.e. mW·h/cm or μW·h/cm). A2.3 Measurement principles A2.3.1 Measurement location The location where microwave communication equipment check-in operators are often located. The space area where the radiation facilities of microwave communication equipment (such as command room, computer room, power supply room, etc.) are located. Fixed sentry posts and duty points near microwave communication equipment. The main area near the transmitting antenna of microwave communication equipment. A2.3.2 Measure the hazardous parts of the human body The spatial positions corresponding to the three points of the check-in operator's eyes, chest and lower abdomen. The area near the transmitting antenna and the space where the auxiliary facilities are located must have frequent human activities at no less than three points (below the height of the human body) A2.3.3 Measurement data Based on the maximum value measured by the measuring instrument in the direction of the measurement position, the measurement needs to be repeated 2-3 times at each measurement position and the average value is taken. A2.3.4 Measurement status Based on the normal working status of microwave communication equipment. A2.4 Records Make good records of microwave radiation measurements. Attachment B Radiation measurement conditions for ultra-short wave communication equipment (Supplement) B1 Scope of application This appendix is applicable to radiation measurements of various types of ultrashort wave communication equipment in the frequency range of 30-300MHz, both for continuous waves and pulse waves. B2 Content Including measuring instruments and measurement principles and methods. B2.1 Measuring Instruments Use a field strength meter with a sufficient measuring range calibrated by a national fixed-point measurement unit for measurement. B2.2 Measurement unit The measurement unit of ultrashort wave radiation is expressed in volts/meter (V/m). />B2.3 Measurement principles B2.3.1 Measurement location The location of the ultra-short wave communication equipment check-in operator. A fixed duty point near ultra-short wave communication equipment. The main area near the transmitting antenna of ultra-short wave communication equipment. B2.3.2 Measurement data Based on the maximum value measured by the measuring instrument in all directions of the measurement position. Measurements need to be repeated 2-3 times at each measurement position. average value. B2.3.3 Measurement status Based on the normal working status of ultra-short wave communication equipment. B2.4 Records Make good records of ultrashort wave radiation measurements. Appendix C Conversion of electric field strength in the ultra-short wave band (reference part) C1 Electromagnetic wave measurement in the ultra-short wave band with a frequency of 30-300MHz The unit usually does not use average power density, but is expressed in terms of average electric field strength. The common unit of measurement is volt/meter (V/m). C2 is considered as a plane electromagnetic wave in free space. The conversion formula considering electric field strength and average power density is as follows: E= In the formula: E - average electric field strength, V/m Pd - average power Density, W/m. C3 According to the GJ B7 regulations, the allowable exposure value and the allowable exposure upper limit of the ultra-short wave band are converted into average electric field intensity according to the above formula as follows: C3.1 Pulse wave C3.1.1 The average microwave radiation power density of 25μW/cm is equivalent to the average electric field strength of the ultra-short wave band of 9.7V/m. C3.1.2 The average microwave radiation power density of 2mW/cm is equivalent to the average electric field strength of the ultra-short wave band of 86.8V/m. C3.2 Continuous wave C3.2.1 The average power density of microwave radiation is 50μW/cm, which is equivalent to the average ultrashort wave electric field strength of 13.7V/m. C3.2.2 The average power density of microwave radiation is 4mW/cm, which is equivalent to the average ultrashort wave electric field strength of 122.8V/m. Additional notes: This standard was proposed by the Ministry of Machinery and Electronics Industry of the People's Republic of China and the State Council. This standard is drafted by the 54th Institute of the Ministry of Mechanical and Electronic Industry.