By sion932 
With the rapid development of electronic information technology, electromagnetic interference (EMI) and electromagnetic compatibility (EMC) have become critical issues affecting the normal operation of electronic equipment and systems. To standardize the design, construction, and acceptance of electromagnetic shielded enclosures, the Ministry of Housing and Urban-Rural Development of the People’s Republic of China issued the national standard GB/T 50719-2011 Technical Code for Electromagnetic Shielded Enclosure. This standard, implemented on June 1, 2012, has played a pivotal role in guiding the construction of electromagnetic shielded enclosure projects in China, ensuring their technical advancement, economic rationality, and safety reliability .
1. Overview of GB/T 50719-2011
GB/T 50719-2011 was compiled by the North Design and Research Institute in conjunction with relevant units in response to the request of the former Ministry of Construction’s “Notice on Issuing the 2006 Project Construction Standard Specification Formulation and Revision Plan (Second Batch)” (Jianbiao [2006] No. 136) . During the compilation process, the compiling group conducted extensive research on domestic and foreign electromagnetic shielding technologies, analyzed existing electromagnetic shielded enclosure projects, summarized practical experience in planning, design, and implementation, absorbed the latest scientific research achievements in electromagnetic shielding, and coordinated with relevant national standards .
The standard consists of 8 chapters and 4 appendices, covering general provisions, terms, classification of electromagnetic shielded enclosures, basic requirements, engineering design, design of special-purpose electromagnetic shielded enclosures, installation engineering, and construction acceptance . It is applicable to the design, construction, and acceptance of new, renovated, and expanded electromagnetic shielded enclosure projects . In addition to complying with this standard, such projects shall also meet the requirements of other current national standards .
2. Core Technical Requirements of the Standard
2.1 Classification of Electromagnetic Shielded Enclosures
GB/T 50719-2011 classifies electromagnetic shielded enclosures into three categories based on their frequency range, shielding effectiveness indicators, structural forms, and main applications: simple electromagnetic shielded enclosures, general electromagnetic shielded enclosures, and high-performance electromagnetic shielded enclosures . The key characteristic indicators of each category are clearly defined:
- Simple electromagnetic shielded enclosures: The frequency range is usually 150kHz~1GHz, the electric field shielding effectiveness is ≤60dB, and the structural form is mostly assembled or welded. They are mainly used to prevent the impact of radio frequency electric and magnetic fields and are often built relying on the main building .
- General electromagnetic shielded enclosures: The frequency range is 10kHz~18GHz, the electric field shielding effectiveness is >60dB, and they adopt more standardized structural designs. They are widely used in testing, confidentiality, engineering experiments, and research .
- High-performance electromagnetic shielded enclosures: The frequency range covers 50Hz~40GHz, the electric field shielding effectiveness is ≥100dB, and they require high-precision materials and manufacturing processes. They are suitable for special scenarios with strict electromagnetic shielding requirements, such as nuclear magnetic resonance (NMR) rooms .
2.2 Key Design Requirements
The engineering design chapter of GB/T 50719-2011 is the core part of the standard, covering general provisions, index determination, material selection, structural design, and design of shielding doors, windows, and waveguides .
In terms of material selection, the standard stipulates that the selection of shielding materials should comprehensively consider factors such as shielding effectiveness, cost, corrosion resistance, and construction difficulty. Low-carbon steel plates are preferred when there are no special requirements . For enclosures operating at frequencies below 1kHz, high-permeability materials such as pure iron plates, permalloy, and high-permeability silicon steel sheets should be used to ensure effective shielding of low-frequency magnetic fields . For special-purpose enclosures such as NMR rooms, non-ferromagnetic materials such as aluminum, copper, or stainless steel must be selected to avoid affecting the normal operation of the equipment . Simple electromagnetic shielded enclosures can use metal mesh as the shielding material, and the specific selection should comply with the provisions of Appendix B of the standard .
In structural design, electromagnetic shielded enclosures are divided into simple, assembled, and welded types according to their structural forms . Simple enclosures should rely on the main building, and the seams of metal mesh or metal plates should be lapped or welded to ensure shielding integrity . Assembled enclosures are composed of modular shielding units, and durable and conductive electromagnetic sealing strips should be installed at the joints of the modules to ensure shielding effectiveness . Welded enclosures adopt integral welding of steel profiles and shielding plates, and the spacing of columns and beams should meet mechanical performance and deformation control requirements .
For the design of shielding doors and windows, the standard requires that the structural form of shielding doors should be reasonably selected according to factors such as door opening size, transportation conditions, and shielding effectiveness indicators. Common types include knife-gate type, double knife-gate type, and flat pressure type . The gaps between the door frame and the door leaf should be equipped with comb-shaped beryllium copper spring sheets or other elastic sealing materials . If windows are set in the enclosure, inward-opening windows or sliding windows should be used, and shielding nets or special shielding windows should be installed . The shielding effectiveness of shielding doors and windows should be 6dB higher than the enclosure’s shielding index .
In addition, the standard also specifies the design requirements for截止波导管, power supply and lighting, insulation, lightning protection and grounding, safety prevention, fire alarm, communication and information systems, ventilation, and water (gas) pipelines of electromagnetic shielded enclosures .
2.3 Installation and Acceptance Requirements
GB/T 50719-2011 puts forward clear requirements for the installation process of electromagnetic shielded enclosures, emphasizing that the installation of shielding bodies, shielding doors and windows,截止波导管, and filters should comply with design documents and construction specifications . During the installation process, attention should be paid to the sealing and conductivity of joints to avoid electromagnetic leakage .
The acceptance of electromagnetic shielded enclosure projects includes two parts: construction quality acceptance and shielding effectiveness testing . The construction quality acceptance covers the quality of materials and components, the installation quality of structural parts, and the completion of supporting systems . The shielding effectiveness testing should be carried out in accordance with the methods specified in the standard, and the testing frequency range and indicators should meet the design requirements . Only when both the construction quality and shielding effectiveness meet the standard requirements can the project be accepted .
3. Significance and Application of the Standard
As an important national standard in the field of electromagnetic shielding engineering, GB/T 50719-2011 has unified the technical requirements and construction standards for electromagnetic shielded enclosure projects in China, which is of great significance for improving the quality and level of electromagnetic shielded enclosure projects, ensuring the normal operation of electronic equipment and systems, and promoting the healthy development of the electromagnetic shielding industry .
This standard is widely used in various fields that require electromagnetic shielding, such as military, aerospace, communications, medical, and scientific research . For example, in the medical field, it guides the construction of NMR rooms and other medical facilities that are sensitive to electromagnetic interference; in the scientific research field, it provides technical support for the construction of electromagnetic compatibility test chambers and precision instrument laboratories; in the military and aerospace fields, it ensures the confidentiality and reliability of electronic equipment and communication systems .
GB/T 50719-2011 Technical Code for Electromagnetic Shielded Enclosure is a comprehensive and systematic technical standard that covers the entire process of electromagnetic shielded enclosure projects from design and construction to acceptance. It not only summarizes the practical experience of domestic electromagnetic shielding engineering but also absorbs advanced international technical achievements, providing strong technical support for the standardized development of China’s electromagnetic shielding industry. With the continuous progress of electromagnetic technology and the increasing demand for electromagnetic shielding, this standard will continue to play an important role in guiding engineering practice. At the same time, with the emergence of new materials, new processes, and new technologies, the standard may also need to be continuously revised and improved to adapt to the new development needs of the industry.
References
- Ministry of Housing and Urban-Rural Development of the People’s Republic of China. GB/T 50719-2011 Technical Code for Electromagnetic Shielded Enclosure[S]. Beijing: China Planning Press, 2012.
- Ministry of Housing and Urban-Rural Development of the People’s Republic of China. Announcement on Issuing the National Standard “Technical Code for Electromagnetic Shielded Enclosure”[Z]. 2011.