07Design
Principles Design
The hospital is equipped with medical gases such as oxygen, negative pressure suction, and compressed air. The pipe network system consists of pipes, equipment belts, instruments, valves and terminals. The terminal oxygen consumption in the ward is determined by 40~80l/(min·bed), and the terminal pressure is determined by 0.4~0.45MPa.
The terminal consumption of negative pressure suction is determined by 30~80l/(min·bed), and the terminal pressure is determined by -0.03~-0.07MPa. The terminal consumption of compressed air is determined by 15~25l/(min·bed), and the terminal pressure is determined by 0.4~0.45MPa. The oxygen gas source is a liquid oxygen tank, and a temporary oxygen supply interface for the tanker is reserved. The oxygen consumption should be fully considered according to the use requirements of emergency temporary infectious disease hospitals.There are 6 20m3 liquid oxygen storage tanks in total, with a total liquid oxygen storage of 120m3; each storage tank is equipped with a 1200m3/h vaporizer with a total vaporization capacity of 7200m3/h, ensuring the overall oxygen supply of the hospital.
The negative pressure system is composed of vacuum pump, water vapor separator, negative pressure vacuum tank, instrument and pipeline valve. The compressed air system is composed of compressed air equipment source and compressed air pipe network system, and the configured screw-type compressed air group is used for two purposes and one for backup.
Compressed air room

Negative pressure suction air machine room

Ward medical gas equipment belt

Outdoor pipe network layout
The main pipes of oxygen, negative pressure suction and compressed air are connected from the computer room and then buried into the isolation ward. The medical gas mains in the isolation ward are mainly laid on the roof of the medical and nursing area, and the branch pipes of each ward pass through their respective roofs and enter the corresponding area. A DN150 oxygen main pipe and a DN80 negative pressure suction main pipe are respectively set in the north and south areas, a bypass pipe is installed between the oxygen main pipes in each area, and a valve is installed on the medical gas branch pipe connected to each nursing unit. It can not only ensure that different areas are used in batches without interfering with each other, and at the same time, the pipelines are used as backup for each other, which effectively improves the reliability of the oxygen supply system. General diagram The schematic diagram of the medical gas pipeline is as follows:

Installation and commissioning

At present, various gas-using areas have been gradually ventilated, the pressure of the oxygen delivery pipeline is stable, and the delivery volume is relatively stable. The liquid oxygen storage tanks and vaporizers are put into use in batches according to the actual usage, which can effectively ensure the oxygen supply.

08 Analysis
Simulation program
In the design process, in order to fully evaluate whether the exhaust gas emissions from the polluted area will affect the surrounding environment of the project, the design process received strong support from Professor Lu Xinzheng of Tsinghua University and his team. Professor Lu Xinzheng and his team proposed a rapid simulation method for the environmental impact of temporary hospital exhaust. This method is based on the open source fluid mechanics calculation software FDS, and realizes the rapid modeling of temporary hospital buildings. Distributed computing based on cloud computing platforms and monitoring and visualization of harmful air flows provide specialized tools for rapid analysis during the design phase of temporary hospitals.

┃ Hazardous gas trajectory and concentration isosurface map

┃ 3D FDS model of Leishenshan Hospital

Main conclusions and guidance for design
1. According to research by Jiang Yi and others, for the SARS virus, it is no longer transmissible after being diluted 10,000 times. The simulation results show that the elevation of 4.5m exhaust outlet can meet the requirement of 10,000 times the air dilution of fresh air outlet.
2. After raising the elevation of the exhaust outlet to 4.5m, it can effectively reduce the relative concentration of polluted air on the elevation surface of the fresh air outlet (3m).
3. In order to ensure the health and safety of medical staff in the negative pressure isolation ward area and protect the outdoor environment, the air supply system of this project adopts three-stage filtration of coarse-efficiency (G2) + medium-efficiency (F7) + high-efficiency (H13), and the exhaust system adopts high-efficiency (H13). After filtering, it is connected to an altitude of 4.5m for discharge, and the design scheme meets the simulation expectations.

09 Conclusion
This time, the HVAC design of Leishenshan Hospital was first reviewed by a professional to determine the technical plan. Design, proofreading, review, and modification were performed to improve work efficiency and avoid rework. A reasonable and stable design plan is the biggest guarantee for the construction of Leishenshan Hospital. During the construction process of the project, actively communicate and cooperate with all parties involved in the project construction, and send experienced designers to inspect the site every day, day and night, to find and solve problems in the construction process as soon as possible. At the same time, on-site guidance is given to the construction of key and difficult points. Under the background of the rapid development of the epidemic, the extremely short project construction period and the great pressure on equipment procurement, everyone in the design team withstood the pressure and rose to the challenge. He has made his due contribution to the effective fight against the epidemic, and escorted the smooth construction of Leishenshan Hospital with the professional standards and professional ethics of the HVAC staff of the Central South Hospital.