National Standard for Engineering Construction “ Data center After three years of relentless effort by the drafting team, the “Design Code” was approved by expert review on May 5, 2015 and is currently in the stage of submission for approval.

I. Data centers are the foundation of all informationization.

Premier Li Keqiang stated in the Government Work Report: Emerging industries and new business models represent frontiers of global competition. We will launch major projects in high-end equipment, information networks, integrated circuits, new energy, new materials, biopharmaceuticals, aero-engines, gas turbines, and other fields, and foster a number of emerging industries into leading sectors. We will also formulate an “Internet Plus” action plan to promote mobile internet, Cloud computing 、 Big Data Integrating the Internet of Things and other technologies with modern manufacturing will promote the healthy development of e-commerce, the industrial internet, and internet finance, and guide internet enterprises in expanding into international markets.

Modern information technologies such as cloud computing, the Internet, the Internet of Things, and big data have become vital pillars of the national economy. At the heart of digitalization lies the data center; indeed, without data centers, there can be no progress in digitalization.

II. Purpose of Standardization

1. On average, a new generation of electronic information technology emerges every 2.5 years, and the advancement of each generation invariably drives the development of supporting technologies—such as data center environmental requirements, building and structural design, air conditioning and ventilation, electrical systems, electromagnetic shielding, network systems and cabling, intelligent building systems, water supply and drainage, and fire protection—and these advancements, in turn, depend on the establishment of relevant technical standards and specifications.

2. GB 50174-2008, “Code for Design of Electronic Information System Computer Rooms,” was promulgated and came into effect in 2008. By 2015, the code had been in use for seven years, indicating that electronic information technology had advanced through three generations, thereby necessitating corresponding revisions to the standard.

3. The primary purpose of renaming the “Design Code for Electronic Information System Computer Rooms” to the “Data Center Design Code” is to align with current domestic data center construction needs and to facilitate greater international exchange.

III. Principles for Standardized Drafting

1. Principle of Feasibility

This code, while adhering to relevant national laws, regulations, and standards, emphasizes the practicality and feasibility of design methodologies, thereby providing designers with applicable design approaches.

2. Principle of Advancement

The “Data Center Design Code” is formulated on the premise of meeting the development needs of China’s data center industry, while drawing on best practices from international data center design and incorporating the specific characteristics of the Chinese data center sector to introduce additional provisions tailored to the industry. The code focuses primarily on aspects such as data center reliability, availability, security, energy efficiency, and environmental protection, demonstrating a certain degree of technological advancement and forward-looking vision.

3. Principle of Scientific Rigor

The design principles and methodologies set forth in this specification synthesize the accumulated experience of the data center industry both domestically and internationally. They are the result of years of practical application by numerous industry experts, grounded in currently effective relevant laws, standards, and codes, and carefully tailored to the unique characteristics and specific requirements of the data center sector.

4. Principle of Coordination

The design principles and methods set forth in this specification are aligned with relevant national and industry regulations, standards, and codes, while also taking into account alignment and coordination with applicable international standards.

5. Principle of Standardization

During the development of this standard, strict compliance was maintained with the “Regulations on the Preparation of Engineering Construction Standards” issued by the Ministry of Housing and Urban–Rural Development (Document No. [2008]182 of the Ministry of Housing and Urban–Rural Development) to ensure the standard’s standardized preparation. The drafting process was divided into the following stages: preparatory stage, draft for public comment, draft for review, and draft for approval.

6. Mandatory Provisions

All engineering construction standards pertaining to quality, safety, hygiene, environmental protection, energy conservation, and other areas subject to state control shall be formulated, with due attention paid to their coordination with other national standards and codes.

IV. Introduction to Selected Revisions

1. Supplement the performance requirements for Tier A data centers in light of developments in Internet and cloud computing data center technologies.

(1) The infrastructure of a Tier A data center shall be configured as a fault-tolerant system, such that, during the operation of electronic information systems, it can continue to ensure the normal functioning of these systems even after a single accidental event or during maintenance and inspection of individual system components. Tier A data centers encompass the performance requirements of both Tier B and Tier C data centers, while imposing even higher standards. Such accidental events include operator error, equipment failure, and interruptions of the primary power supply; design typically assumes the occurrence of a single accidental event, without accounting for multiple simultaneous incidents. Similarly, maintenance and inspection are planned to accommodate the repair of equipment in only one system at a time, rather than concurrent repairs across multiple systems. Following a single accidental event or during maintenance and inspection of individual system components, the infrastructure must be capable of meeting the basic operational requirements of electronic information equipment.

(2) When an Tier-A data center simultaneously meets the following requirements, the power supply for electronic information equipment may be provided through a combined power supply system consisting of an uninterruptible power supply (UPS) system and the utility grid.

1) During equipment or line maintenance, the normal operation of electronic information equipment shall be ensured;

2) The power quality of the mains-supplied power shall meet the requirements for the normal operation of electronic information equipment;

3) The power factor at the utility power connection point shall comply with the requirements of the local power supply authority.

4) The diesel generator system shall be capable of withstanding the effects of capacitive loads;

5) The total harmonic current content injected into the power grid shall not exceed 10%.

The primary objective of this provision is to reduce the total cost of ownership (TCO) of data centers while ensuring availability. Electronic information equipment is classified as a capacitive load, and the diesel generator system must be capable of accommodating the effects of such loads; when the harmonic distortion of the current generated by the electronic information equipment exceeds 10%, harmonic mitigation measures shall be implemented.

(3) When two or more data centers located in different regions are constructed concurrently as mutual backups, with real-time data transmission and business continuity requirements met, the infrastructure of these data centers should be configured as a fault-tolerant system; alternatively, it may be configured as a redundant system. This scenario applies to Tier A data centers, primarily those used for cloud computing and Internet services. When two or more data centers established either within the same city or in different locations serve as mutual backups, with real-time data replication and business continuity requirements satisfied, the fault-tolerant functionality is already realized among the data centers; therefore, their infrastructure may be configured as either fault-tolerant or redundant, depending on the specific circumstances.

2. In light of recent developments in data center construction, additional provisions have been added regarding data center site selection, stipulating that such sites must meet the following requirements:

1) Power supply shall be ample and reliable, communications shall be swift and unimpeded, and transportation shall be convenient;

2) Data centers that use water-evaporation cooling for refrigeration must have an adequate water supply.

3) The natural environment shall be kept clean, and the ambient temperature shall be conducive to energy conservation;

4) It shall be located away from areas that generate dust, cooking fumes, harmful gases, or that are used for the production or storage of corrosive, flammable, or explosive materials.

5) Should be located away from areas prone to flooding, fire, and natural disasters;

6) Should be kept away from strong vibration sources and strong noise sources;

7) Strong electromagnetic field interference should be avoided;

8) Tier-A data centers should not be located directly above public parking garages;

9) Large and medium-sized data centers should not be located in residential or commercial districts.

On the premise of ensuring reliable power supply, unimpeded communications, and convenient transportation, data center construction should prioritize locations with relatively low ambient temperatures, as this helps reduce energy consumption.

When electronic information systems are exposed to factors such as dust, harmful gases, vibration and shock, and electromagnetic interference, they may experience computational errors, malfunctions, wear and corrosion of mechanical components, and reduced service life. Therefore, the site selection for data centers should, whenever possible, avoid areas that generate dust, emit harmful gases, or are sources of strong vibration and noise, and should also steer clear of locations subject to severe electromagnetic interference.

Areas with potential flood risks primarily include the banks of rivers, streams, lakes, and coastlines. For Tier A data centers, the flood protection standard should be designed for a 100-year return period; for Tier B data centers, the standard should be designed for a 50-year return period. When selecting a site within the campus, data centers should not be located in low-lying areas.

From a safety perspective, Tier-A data centers should not be located directly above public parking garages. If it is unavoidable to site the data center directly above a parking garage, collision- and explosion-proof measures must be implemented for the parking structure.

Cooling towers and outdoor units in air-conditioning systems generate significant noise during operation. If a data center is located within a residential community or too close to residential buildings, this noise can adversely affect residents’ daily lives. Moreover, the high population density in residential and commercial areas is detrimental to the safe and reliable operation of data centers.

3. In light of domestic and international demand for disaster recovery data centers, add provisions related to disaster recovery data centers.

The composition of the disaster recovery data center shall be divided into restricted areas, general areas, and dedicated areas based on security requirements, functional use, and personnel categories. Restricted areas should include the main computer room, auxiliary areas, and support areas; general areas should include the emergency command center, external assistance work area, media briefing area, rest rooms, storage rooms, medical facilities, and parking lots; and dedicated areas should include assembly areas, waiting areas, and intermediate preparation areas.

Restricted areas are locations where access is limited to specific categories of personnel based on security requirements. These personnel categories primarily include disaster recovery data center staff, users, equipment and material suppliers, and visitors.

The general area is designated for disaster recovery operations, routine training, and office work. The Emergency Command Center provides centralized monitoring and operational management of the disaster recovery data center; in the event of a disaster, disaster recovery personnel issue recovery instructions from this center, coordinate resources, liaise with clients, and execute the disaster recovery procedures. The Emergency Command Center should be equipped with dedicated telephone lines, equipment for acquiring external information, and a dedicated conference room. The External Support Work Area is an office space provided for users and equipment communication vendors to support disaster recovery or routine testing activities. The Media Briefing Area is intended for communication with news organizations and external personnel; it should be located away from restricted areas and the Emergency Command Center, and access should be strictly limited to invited media representatives and authorized external personnel. The Rest Room should include restrooms, changing rooms, showers, and other facilities to meet the short-term living needs of disaster recovery personnel. The Storage Room is used for the temporary storage of daily necessities. The Medical Room can provide emergency medical assistance to disaster recovery personnel.

The dedicated area is a space provided for users to utilize during the recovery process and to station equipment. The assembly area is where all disaster recovery personnel gather and receive orders; it may be an open space, a lobby, or an auditorium capable of accommodating all such personnel, and should be equipped with a public-address system. The waiting area is where disaster recovery personnel load, unload, and inspect relevant equipment. The intermediate preparation area is used for testing electronic information equipment.

4. In accordance with developments in electronic information equipment technology, changes in relevant international standards, and energy-saving requirements, the temperature and other parameters of the data center’s main computer room shall be adjusted. The temperature, dew point temperature, and relative humidity in the main computer room and auxiliary areas shall meet the operational requirements of the electronic information equipment; where no specific requirements are stipulated, the values specified in the following table shall be applied.

When cabinets or racks are arranged in a hot–cold aisle configuration, the ambient temperature and dew point temperature in the main computer room shall be based on measurements taken in the cold aisles; when electronic information equipment is not arranged in a hot–cold aisle configuration, the ambient temperature and dew point temperature in the main computer room shall be based on measurements taken in the supply-air zones. The main computer room has recommended and permissible values for ambient temperature, relative humidity, and dew point temperature; a main computer room designed according to the recommended values offers greater advantages for electronic information equipment in terms of reliability, energy consumption, operational performance, and service life. When the environmental requirements for temperature and relative humidity can be relaxed for electronic information equipment, the ambient temperature, relative humidity, and dew point temperature in the main computer room may be designed using the permissible values.

5. To enhance the reliability of the data center’s backup power supply, the performance requirements for the standby diesel generator sets shall be increased.

The performance rating of standby diesel generator sets shall not be lower than G3; for Class A data centers, the generator sets shall be capable of continuous, unlimited-operation, with an output power sufficient to meet the data center’s peak average load. For Class B data centers, the generator set output power may be selected based on the 500-hour limited-time operating rating.

In the national standard GB/T 2820.1, “Reciprocating Internal Combustion Engine–Driven Alternating Current Generating Sets—Part 1: Application, Ratings, and Performance,” the performance of generating sets is classified into G1, G2, G3, and G4. Given that data centers have stringent requirements for the output frequency, voltage, and waveform of generating sets, the performance rating of such units shall not be lower than G3.

Continuous, unlimited-duration operation of the generator set is a fundamental requirement for Tier A data centers. The large average load refers to the value obtained by performing a load calculation based on the demand factor method, taking into account the capacities of information technology equipment, air-conditioning and refrigeration systems, lighting, and other loads. When determining the output power of the generator set, the impact of harmonics generated by the load on the generator set must also be considered.

According to the national standard GB/T 2820.1, “Reciprocating Internal Combustion Engine–Driven Alternating Current Generating Sets—Part 1: Application, Ratings, and Performance,” the output power of generating sets is classified into four categories: continuous power, base power, limited-time operation power, and emergency standby power. Taking into account the load characteristics of a Tier B data center, the reliability of the utility power supply, and the economic feasibility of the investment, the limited-time operation power among the generating set’s output power ratings is sufficient to meet the operational requirements of a Tier B data center.

6. From a safety perspective, add requirements for backup power supply design and grounding practices.

(1) In 3–10 kV standby diesel generator systems, the neutral grounding method shall be determined based on the grounding method of the common power supply and the value of the single-phase-to-ground capacitive current in the distribution lines. When the common power supply employs a non-effective grounding system, the diesel generator system should preferably adopt an ungrounded neutral. When the common power supply employs an effective grounding system, the diesel generator system may use either an ungrounded neutral or a low-resistance grounded neutral. If an ungrounded neutral is adopted for the diesel generator system, a ground-fault alarm shall be provided. When multiple diesel generator sets operate in parallel and a low-resistance grounding system is used, the grounding method of any one of the units may be adopted.

The grounding methods commonly used in China’s power systems are broadly classified into two categories: effectively grounded neutral systems and ungrounded neutral systems. Ungrounded neutral systems include direct ungrounded neutrals, resonant grounding (grounded via an arc-suppression coil), resonant–low-resistance grounding, and high-resistance grounding. Among effectively grounded systems, low-resistance grounding is employed for voltages ranging from 6 kV to 35 kV. In 3–10 kV diesel-generator systems, the choice of neutral-grounding method is closely related to the magnitude of the single-phase-to-ground capacitive current in the distribution network. Given that data centers typically have a limited number of 10-kV electrical equipment and cables, the single-phase-to-ground capacitive current generally does not exceed 30 A; therefore, the neutral of the diesel-generator system is usually left ungrounded. When the utility power supply employs a low-resistance grounding system and a single-phase-to-ground fault on any circuit triggers protective devices to trip without disrupting data-center operations, the diesel-generator system’s neutral may also be grounded via a low-resistance scheme. Furthermore, when multiple diesel-generator sets operate in parallel and one of them is selected for grounding, the current-carrying capacity of the grounding resistance must be carefully calculated.

(2) In standby diesel generator systems with a voltage of 1 kV and below, the neutral-point grounding method should preferably be consistent with that of the low-voltage distribution system. When multiple diesel generator sets operate in parallel and the low-voltage distribution system has a directly grounded neutral, the neutral points of the individual units may be grounded through reactors, or the grounding method of one of the units may be adopted. In such cases, to minimize circulating currents in the neutral conductor, either reactor-based neutral grounding or the grounding method employed for one of the units is recommended.

V. Conclusion

With the rapid development of next-generation information technologies, “new economic infrastructure” — epitomized by broadband, wireless internet, and cloud computing — is poised to become a key investment area; information consumption, e-commerce, and electronic finance are thriving; e-healthcare, mobile energy, and online home decoration are gathering momentum; and “Internet Plus” is set to drive transformative change across industries, unlocking enormous potential. Underpinning all of this is the data center, which, through the industrial value chain, fuels the rapid growth of various sectors. The Data Center Design Code, as the standard for data center construction, will ensure that data centers are technologically advanced, energy-efficient and environmentally friendly, and safe and reliable. The national engineering construction standard, Data center After three years of relentless effort by the drafting team, the “Design Code” was approved by expert review on May 5, 2015 and is currently in the stage of submission for approval.