Ventilation pipe is a metal or composite pipe used in ventilation and air conditioning engineering. It is the infrastructure to make the air flow and reduce the concentration of harmful gases. The panel, profile and other main finished materials used in the production and installation of the air duct inside the ventilation duct shall comply with the current national design and relevant product standards, and apply for the factory inspection certificate. When entering the site, the materials shall be accepted according to the current national standards.

一个好的送风系统设计，应该使系统的初始投资和运行成本能够降低。通过遵循以下管道设计的一般准则，仍然可以在系统的初始投资和运行成本之间实现合理的平衡。

A good design of air supply system should reduce the initial investment and operation cost of the system. By following the following general guidelines for piping design, a reasonable balance can still be achieved between the initial investment and operating costs of the system.

1、风管应尽可能呈直线布置

1. The air duct should be arranged in a straight line as far as possible

风管系统采用直线布置，运行能耗和初期投资很低。从成本分析的角度来看，直管的成本远远低于各种弯头和其他管件。因此，在布置风管系统的平面走向时，应尽量减少转弯次数。过于复杂的系统，经常需要定期维护，维护程序复杂且昂贵。所以一个好的控制系统应该尽可能简单可靠，易于维护或者不需要定期维护。控制系统的设计应尽可能考虑将来的修改和扩展。

The air duct system is arranged in a straight line with low energy consumption and initial investment. From the perspective of cost analysis, the cost of straight pipe is far lower than that of various elbows and other pipe fittings. Therefore, in the layout of the plane direction of the air duct system, the number of turns should be reduced as much as possible. Too complex system, often need regular maintenance, maintenance procedures are complex and expensive. So a good control system should be as simple and reliable as possible, easy to maintain or do not need regular maintenance. The design of control system should consider the future modification and expansion as far as possible.
                          

2、标准长度的直管段用于尽量减少各种异径管和接头的数量

2. Standard length straight pipe sections are used to minimize the number of various reducers and joints

标准长度的直管由于加工成本低，建造成本相对较低。从技术上讲，任何非标准长度的矩形风管都可以用作附件，因为它们不能用标准线圈制成。

Due to the low processing cost, the construction cost of standard length straight pipe is relatively low. Technically, any rectangular duct of non-standard length can be used as an accessory because they cannot be made of standard coils.

3、建议采用螺旋圆形风管

3. Spiral circular duct is recommended

圆形风管允许更高的风速。矩形风管的允许风速一般较低。采用圆形风管和较高的送风速度将大大节省投资。与类似的矩形风管系统相比，圆形风管系统可节省30%的钢板。螺旋风管的制造自动化程度高，生产速度快。螺旋风管的成本低于矩形风管，因为镀锌带钢作为原材料的价格低于整个镀锌钢板，加上工厂生产和规格的标准化。另外，由于其支、吊架所需工作量少，安装工作量少，所以总成本较低。

Circular duct allows higher wind speed. The allowable wind speed of rectangular duct is generally low. The use of round duct and higher air supply speed will greatly save investment. Compared with the similar rectangular duct system, the circular duct system can save 30% steel plate. Spiral duct has high degree of automation and high production speed. The cost of spiral duct is lower than that of rectangular duct, because the price of galvanized steel strip as raw material is lower than that of the whole galvanized steel sheet, plus the standardization of factory production and specifications. In addition, the total cost is low due to the less workload of support and hanger and installation.