GA/T 1711-2020 English PDF (GAT1711-2020)

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GA/T 1711-2020: Controlling limits and measurement methods for electromagnetic environment in surveillance center of security systems
GA/T 1711-2020
GA
PUBLIC SAFETY INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 13.020
A 91
Controlling limits and measurement methods for
electromagnetic environment in surveillance center of
security systems
ISSUED ON: FEBRUARY 11, 2020
IMPLEMENTED ON: AUGUST 01, 2020
Issued by: Ministry of Public Security of the People's Republic of China
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Terms and definitions ... 4 
4 Controlling limits ... 5 
5 Measurement method ... 6 
5.1 Requirements for measuring instruments ... 6 
5.2 Measuring position ... 6 
5.3 Measurement equipment layout ... 7 
5.4 Measurement frequency band and physical quantity ... 8 
6 Measurement time and data processing ... 8 
7 Measurement record or report ... 8 
Annex A (informative) Examples for measuring positions of surveillance center
of security system ... 10 
Bibliography ... 12 
Controlling limits and measurement methods for
electromagnetic environment in surveillance center of
security systems
1 Scope
This Standard specifies controlling limits and measurement methods for
electromagnetic environment in surveillance center of security systems.
This Standard is applicable to electromagnetic environment evaluation for
surveillance center of security systems. The electromagnetic environment
evaluation in areas such as security inspection and radio frequency reading in
the security protection system may refer to this Standard to implement.
2 Normative references
The following referenced documents are indispensable for the application of
this document. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any
amendments) applies.
GB 8702-2014, Controlling limits for electromagnetic environment
GB 50348-2018, Technical code for engineering of security and protection
system
HJ 972, Monitoring method for electromagnetic radiation environment
3 Terms and definitions
For the purposes of this document, the terms and definitions defined in GB
8702-2014, GB 50348-2018 as well as the followings apply.
3.1 surveillance center of security system
the central control room that receives and processes security system
information, handles alarm events, and manages control system equipment; it
is usually divided into guard area and equipment area
5 Measurement method
5.1 Requirements for measuring instruments
5.1.1 Electric field and magnetic field measuring equipment below 100kHz meet
the following requirements:
a) 8Hz~100kHz electric and magnetic field measuring instruments shall be
used. Discrete probes can be used for electric and magnetic field
measuring instruments. It can also be a combination of the two;
b) Three-dimensional probe shall be used;
c) When the probe is connected to the host (handheld) through an optical
fiber, the fiber length shall not be less than 2.5m;
d) Measuring instruments shall be battery powered. Continuous working time
shall not be less than 12h;
e) The probe holder shall be made of non-conductive material;
f) The measuring range of electric field strength of the electric field probe
shall cover at least 3V/m~100kV/m. The measuring range of magnetic
induction intensity of the magnetic field probe shall cover at least
30nT~1mT;
g) The area of the magnetic field probe shall be less than 0.01m2;
h) There shall be automatic data storage function. Storage interval shall not
be greater than 15s.
5.1.2 Electric and magnetic field measuring instruments above 100kHz shall
meet the requirements of HJ 972.
5.1.3 When a non-selective frequency tester is used for measurement and the
measurement result is higher than the limit in Table 1, it needs to use frequency
selective tester for final measurement.
5.2 Measuring position
5.2.1 Guard area of surveillance center of security system
5.2.1.1 Staff position on duty
Measure the positions of the guards in the surveillance center of security
system. When the working posture is sitting, the height of the measuring point
from the ground is 1.2m, 1m and 0.8m respectively. When the posture is
5.4 Measurement frequency band and physical quantity
The principles for selection of measurement frequency band and physical
quantity are as follows:
a) Determine the measurement frequency band and physical quantity
according to the frequency range of the electromagnetic field in the
measurement environment;
b) When the frequency is less than 30MHz, the electric field intensity and
magnetic induction intensity shall be measured;
c) When the frequency is not less than 30MHz, only the electric field strength
or magnetic field strength, or equivalent plane wave power density can be
measured.
6 Measurement time and data processing
The measurement shall be performed during the normal working hours of the
equipment of surveillance center of security system. Each height of each
measuring point is measured 5 times respectively. Each measurement time
shall not be less than 15s. Take the steady state value. Record the maximum
value of 5 times as the measurement result.
If the measurement result at a certain position exceeds 30% of the
environmental limit in Table 1, the physical quantity shall be measured for not
less than 24h (the battery replacement time is not included) at the measurement
position. It shall be recorded at least every 15s. Respectively count the
maximum, minimum, 95% and 50% time probability of not exceeding the field
strength values E95 and E50. Draw the distribution diagram of electric field or
magnetic field and time as needed. List the maximum, minimum, E95 and E50.
Use E95 as the basis for evaluation.
NOTE: If measure once every 15s and continuously measure for 24h, a total of 5760
measurement data will be generated. When processing, sort all data from largest to
smallest. Take the first data as the maximum value. Take the 289th data as E95. Take the
2880th data as E50. Take the 5760th data as the minimum value.
7 Measurement record or report
The measurement record and report for electromagnetic environment of the
surveillance center of security system shall include at least the following:
- Environmental conditions such as temperature and relative humidity during