Construction of communication equipment rooms and layout of equipment

                                                    Construction and equipment layout of the communication machine room

How to build a large machine room, to build oneData center machine roomIt is not a simple task; the construction of a data center is an overall structure, and any detail planning that is overlooked may lead to problems.

　　Some issues may only be exposed during the lifecycle of the equipment or system. To avoid delays in the construction schedule due to problems arising from inadequate consideration during the construction of the data center, which may require rework after the completion and delivery of the data center, the following are key issues to ensure that the planning and design personnel of the data center adhere to the correct direction.

　　A comprehensive data center construction project generally includes: integrated wiring, anti-static floor installation, ceiling and wall decoration, partition decoration, UPS power supply, dedicated constant temperature and humidity air conditioning, monitoring systems for the machine room environment and power equipment, fresh air systems, leak detection, grounding systems, lightning protection systems, access control, monitoring, fire protection, alarms, shielding projects, etc.

Main aspects of data center construction

　　1. Fire protection system

　　The machine room should have a gas extinguishing system, with the gas cylinder room preferably located outside the machine room. It should be a pipeline structure with nozzles set on the ceiling. The fire alarm system consists of a fire control box, smoke detectors, and temperature sensors connected in a network. The fire protection system in the machine room should use a gas fire extinguishing system, commonly using two types of gases: heptafluoropropane and SDE.

　　2. Precision air conditioning system

　　The task of the precision air conditioning system in the machine room is to ensure that the equipment in the machine room can operate continuously, stably, and reliably. It needs to expel the heat generated by the equipment and other heat sources in the machine room, maintain a constant temperature and humidity state, and control the dust content in the air. Therefore, the precision air conditioning system in the machine room must have the capabilities of air supply, return air, heating, humidifying, cooling, dehumidifying, and air purification. The precision air conditioning system is the most important equipment to ensure a good machine room environment and should adopt a constant temperature and humidity precision air conditioning system.

　　3. Monitoring and access control system

　　The monitoring layout in the machine room contains a large number of servers, cabinets, and racks. Since these cabinets and racks are generally quite tall, there are many blind spots in monitoring. Therefore, when laying out the TV monitoring, the main consideration is the various entrances and exits, installing cameras between each row of cabinets. If the space at each entrance and exit is relatively large, it may be considered to use zoom cameras. For each row of cabinets, fixed-focus cameras can be installed according to the monitoring distance. If the machine room has multiple rooms, it may be considered to install cameras in the UPS room and control room.

　　The access control system in the machine room mostly adopts a non-contact smart IC card integrated management system. This system can flexibly and conveniently specify the personnel, time, and permissions for entering the machine room, preventing damage caused by human factors and ensuring the safety of the machine room.

　　4. Shielding system

　　Electromagnetic interference has a significant impact on computer equipment, which can cause misoperations and data loss, and in severe cases, render computers inoperable. The shielding in the machine room mainly prevents various electromagnetic interferences from damaging the equipment and signals in the machine room. There are two common types: metal mesh shielding and metal plate shielding. The requirements for electromagnetic interference in computer rooms in our country stipulate that the radio interference field strength in the frequency range of 0.15 to 1000 MHz should not exceed 120 dB, and the magnetic field interference strength in the machine room should not exceed 800 A/m (equivalent to 10 Oe). Depending on the shielding effect required by the machine room, the frequency bands for shielding vary, and the materials and construction methods for the shielding system should be selected accordingly. All indicators should strictly comply with national standards.

　　5. Grounding system

　　The machine room should install a good grounding system to provide a stable zero potential in the power supply, serving as a reference voltage for the power system voltage. A good grounding wire is necessary; when the power voltage and signals in computer transmission encounter or generate various interferences, they can be filtered out through high and low-frequency filtering capacitors. Additionally, when encountering lightning, strong power sources near cabinets, and electrical spark interference, a good grounding system in the machine room should protect the computers.

　　Therefore, designing a good grounding system for the machine room is quite important. The grounding system in the machine room is generally divided into the following three types:

　　(1) DC ground: This grounding system connects the power output terminal to the grounding network, making it a stable zero potential. This power ground wire is directly connected to the earth and has a very low grounding resistance.

　　(2) AC ground: This grounding system connects the ground wire of the AC power supply with the grounding points of AC electric devices such as motors and generators, and then connects to the earth.

　　(3) Safety ground: To shield against external interference, leakage, and electrical sparks, all computer cabinets, chassis, shells, panels, and motor housings need to be grounded for shielding, which constitutes the safety ground.

　　General requirements: DC ground resistance should be less than 1 ohm, AC ground resistance should be less than 4 ohms, and safety ground resistance should be less than 4 ohms. The four types of grounding, including AC working ground, safety protection ground, DC working ground, and lightning protection ground, should preferably share a grounding device with a grounding resistance of less than 1 ohm. The connection methods for the grounding system can adopt various forms such as radial, ring, or grid matrix, and different connection methods can be selected based on geographical features.

　　6. Anti-static floor installation

　　In the construction of the machine room project, the flooring is a very important component. The machine room floor generally uses anti-static raised flooring. The raised floor mainly consists of two parts: a) anti-static raised floor panels; b) floor support system, mainly consisting of beam supports (the supports are divided into upper and lower supports, and the screws can be adjusted to level the floor surface). The specifications are mainly 600*600mm. Installation height: 350±20mm, with a general resistance value between 1×10^7—1×10^10 ohms, and a distributed load greater than 1500kg/m2.

　　The raised floor has the characteristic of being removable, making it convenient for connecting wires and cables of all equipment, as well as for pipeline connections and maintenance. The space under the raised floor can serve as a static pressure air supply chamber, allowing the cold air from the machine room air conditioning to be delivered into the room and the cabinets of heat-generating equipment through the raised floor with airflow distribution outlets. Due to the interchangeability of the airflow outlet floor with general raised floors, the airflow distribution in the machine room can be freely adjusted. The surface under the raised floor generally requires moisture-proof treatment (such as applying moisture-proof paint, etc.), and when installing the anti-static floor, it is also required to install a static leakage system. A static leakage grounding network is laid out, and the static leakage main line is sealed together with the grounding terminal of the machine room safety protection ground to discharge static electricity.

　　7. Power distribution system

　　1) UPS uninterruptible power supply

　　The load in the computer room is divided into main equipment load and auxiliary equipment load. The main equipment load refers to the computer and network systems, external computer devices, and the monitoring system of the computer room. This part of the power distribution system is called the 'equipment power distribution system', which has very high power quality requirements and should use UPS (Uninterruptible Power Supply) to ensure the stability and reliability of the power supply; the auxiliary equipment load refers to air conditioning equipment, power equipment, lighting equipment, testing equipment, etc., and its power distribution system is called the 'auxiliary power distribution system', powered directly by the municipal electricity. In projects with higher requirements for the computer room, the UPS can use direct parallel technology, and its power distribution system is called the N+1 redundant parallel technology. This ensures that when one UPS fails, it can still provide uninterrupted and highly reliable power to all loads, and when expansion is needed, it only requires direct parallel connection to the existing parallel system without the need to add a new UPS power supply system, effectively saving costs. The electrical construction in the computer room should choose high-quality cables, cable trays, and sockets. Sockets should be divided into municipal electricity, UPS, and special waterproof sockets for main equipment.

　　2) Distribution cabinet

　　Computer rooms often use dedicated distribution cabinets to standardize the power distribution system of the computer room, ensuring the safety and rationality of the power distribution system. The distribution box and cabinet should have short circuit and overcurrent protection, and their emergency power-off buttons should be interlocked with the fire alarm. After installation, they should be numbered, and the purpose of each switch inside the box and cabinet should be indicated for easy operation and maintenance. Spare circuits should be reserved in the distribution box and cabinet for future expansion of computer room equipment.

　　The above is just a simple description of the issues to pay attention to in the construction of the computer room from several aspects such as power distribution facilities, weak current control, and equipment protection. In fact, the construction of a computer room project is a comprehensive system engineering that integrates multiple disciplines and fields, including computer network technology, communication technology, architectural decoration, weak current control, air conditioning, electrical engineering, electronics, automatic detection and control, environmental protection, security prevention, and anti-interference. A central computer room that is advanced, reasonable, practical, scalable, displayable, uniquely designed, uses novel materials, and has meticulous construction will inevitably have a certain historical vitality. Let's take a look at the key issues that the design and construction of data center computer rooms adhere to in the correct direction.

　　The design and construction of data center computer rooms adhere to the key issues in the correct direction:

　　1. Where will the data center be built?

　　Analyzing the climate conditions of the location of the new data center is very important. This will help determine the most suitable cooling measures, including water-cooled units, mechanical refrigeration air conditioning, natural air cooling, indirect air cooling, and adiabatic cooling, all aimed at achieving a lower PUE target for the data center facilities.

　　2. How many racks do you need? What are their dimensions?

　　The number of racks determines the space requirements of the data center. The traditional size of IT racks is 600x1000mm (width x depth), and a computer room with an area of 100 square meters can accommodate about 50 racks. Of course, racks also come in other sizes, and knowing the size and number of racks makes it easy to estimate the space required for your data center.

　　3. What tier level of data center do you need?

　　The Tier level of the data center determines the redundancy requirements and power distribution paths of the data center. For a Tier 2 data center, deploying 'N+1' architecture for power and cooling equipment redundancy is sufficient. However, for a Tier 3 data center facility, it typically includes 'N+1' cooling equipment redundancy, dual power 2N power redundancy, and independent dual power distribution racks. Therefore, understanding the tier level of the data center can determine the redundancy design you need.

　　4. What is the average power density per rack?

　　It is important to note that when designing the power capacity of the data center, it should be based on the average power density rather than the maximum rated power. The maximum IT load of the data center is the average power density of the racks multiplied by the number of racks. Then, add the power of the data center's power system, cooling system, and facilities such as switches and storage devices. To avoid incurring expensive costs and to make full use of the power system, adopting a modular strategy is wise, as it can reduce costs without sacrificing future expansion flexibility.

　　5. Operations and maintenance personnel should participate in the planning and design work.

　　a. The operations and maintenance management department's participation in the early planning and design can compensate for the designers' lack of knowledge about system operation and management, improve design quality, and avoid or eliminate design deficiencies.

　　b. Involving operations and maintenance management personnel in planning and design can ensure that the needs of the operations and maintenance phase are fully considered in the planning and design.

　　c. Operations and maintenance personnel participating in the early planning and design can fully understand and grasp the structure, weak links in reliability, legacy issues, and potential risks of the systems they maintain, which helps improve the quality of operations and maintenance and formulate well-founded operations and maintenance plans and feasible renovation plans.

　　6. Due to internal and external factors, failing to correctly address the differences between tendencies, preferences, limitations, and constraints, and not adhering to scientific design principles.

　　a. Influenced by individual decision-makers in approval and decision-making processes, some key functions are adjusted or reduced based on individual opinions, resulting in the final delivered data center functions not meeting operational and maintenance needs.

　　b. Due to tendencies, preferences, or profit-driven motives, some equipment manufacturers may influence the planning and design personnel's scheme formulation and equipment selection during the planning and design phase by exaggerating equipment performance or confusing concepts.

　　7. What level of backup battery is required for the data center's exchange racks or DC racks?

　　Server racks may require 100% DC power deployment, or 100% AC power, or a combination of both. For example, if you are building a data center for hosting purposes, you may have a need for an AC (UPS) power supply system, while if it is to become a telecommunications facility, it may require the deployment of a DC power system. Knowing this will help you understand the size and scale of the DC power or UPS power supply system you need.

　　When deploying backup batteries, it is best to configure them based on a 15-minute backup discharge time. This way, deploying backup batteries will not significantly increase capital expenditures, although it may be difficult to justify, it is more cost-effective. Enterprises need to increase the redundancy of backup generator sets rather than waste more funds by increasing the number of batteries.

　　8. There is a common misconception in the industry of light planning and design, heavy construction?

　　There is a misconception in the industry, especially among user information managers, of light planning and design and heavy construction, mainly reflected in:

　　a. Building the structural body first and then planning the data center, leading to insurmountable difficulties in the planning and design of the data center.

　　b. The phenomenon of starting renovations immediately after the construction and installation of the computer room and equipment is common.

　　c. Determining the equipment first and then the plan, due to the purchased equipment not meeting the functional requirements of the plan, or the site not meeting the installation conditions, resulting in the need to replace the equipment before it has even been put into operation.

　　d. The construction structure is difficult to meet the layout requirements of the data center, resulting in unreasonable planning of the machine room partitions; the outdoor air conditioning units cannot be installed or are too far away; the distance between the power room and the main machine room is too far, increasing transmission and management difficulties, raising costs, and reducing reliability.

　　9. There is a general neglect of the design for system maintainability and repairability.

　　The system is built with one-third construction and two-thirds maintenance; any equipment can fail, and repairability and quick repair have become key indicators for improving availability. The neglect of maintainability and repairability is reflected in:

　　a. The planning and design phase did not consider maintenance channels and maintenance space for the later stage, for example, equipment being too close to the wall, batteries placed against the wall, unreasonable cable layout, cable conduits or racks blocking the upper weak current cable trough, making later maintenance impossible, and maintenance tools difficult to use, etc.;

　　b. When a failure occurs, emergency supplies and spare parts cannot be quickly transported, and there is no operational space for replacing faulty equipment and components, which delays the fault handling time and may even lead to major accidents;

　　c. The redundancy capability of the system during equipment maintenance after a failure should be considered;

　　d. Automated means should be adopted as much as possible to minimize manual operations by maintenance personnel. Relying on manual operations by maintenance personnel in data center maintenance operations involves significant uncertainty and uncontrollability.

　　10. Is there a lack of scientific basis for availability design?

　　System availability is the most important indicator in the planning and design of data centers, but there is a lack of scientific basis during the planning and design; this is mainly reflected in:

　　a. Data centers conduct reliability calculations for each system during planning and design, but currently, different design institutes and designers have not unified the basis and data sources for reliability calculations, resulting in different definitions and results for the design level and reliability of the same data center;

　　b. There are cases where planning and design are conducted first, construction is completed, and then the design level is retroactively deduced, and this retroactive level standard is promoted to data center users. This is a reversed design approach, often leading to a decrease in level due to certain key defects in the design, even though most of the design meets the level requirements;

　　c. Only the availability of equipment or components (subsystems) is considered, while ignoring the impact of the correlation between subsystems on availability within the entire system.

　　11. Is there a common misconception in the industry that emphasizes equipment while neglecting the system?

　　In the industry, especially among planning and design personnel, there is a common phenomenon of emphasizing equipment while neglecting the system and focusing on parts while ignoring the overall picture, mainly reflected in:

　　a. First determining the specifications and models of equipment or even the manufacturers, and then selecting or modifying the design scheme based on the equipment;

　　b. The power supply system is designed with a maximum available level of 2N redundancy, but the result is that only the UPS system has 2N functionality, while the entire power supply system has single-path failure points;

　　c. The entire system is designed as a maximum level redundant fault-tolerant system, but the air conditioning cooling equipment has single-path power supply;

　　d. An AC backup energy diesel generator is configured for the system, but the generator lacks an automatic start function because the planner lacks the understanding that continuous cooling is also an important condition for the continuous operation of the system.

　　Summary:

　　There are many other issues that need to be considered in the construction of new data centers. However, industry experience tells us that mastering these thirteen key basic settings during the construction and design process of data centers will ensure that the final data center design is as close as possible to the actual needs of users.