通风管道工程量计算规则
Calculation rules for quantities of ventilation ducts
1, 薄钢板风管
1. Sheet steel air duct
（1）风管按不同规格以展开面积计算，管上检查孔、测定孔、送风口、吸风口等所占面积不扣除。
(1) The air duct shall be calculated based on the developed area according to different specifications, and the area of inspection hole, measuring hole, air supply outlet, air suction outlet, etc. on the duct shall not be deducted.
（2）计算风管长度时一律以图注中、变径管、天圆地方等管件的长度，但不得包括通风部件（如风阀、风口等）所在位置的长度。风管直径和周长按图注尺寸展开。但咬口风管的接口及翻边量不得计算在展开面积内。
(2) When calculating the length of the air duct, the length of the center line in the drawing shall prevail, including the length of pipe fittings such as elbows, tees, reducer pipes and round places, but not including the length of the location of ventilation components (such as air valves, air vents, etc.). The diameter and perimeter of the air duct shall be expanded according to the dimensions in the drawing. However, the joint and flanging amount of the undercut air duct shall not be calculated within the developed area.
（3）风管导流叶片按叶片的面积计算。
(3) The air duct guide vane is calculated according to the area of the vane.
（4）风管附件（除软性接头按平方米计算外），检查孔、测定孔等按不同类型、规格分别以个为单位计算。
(4) Air duct accessories (except for flexible joints, which are calculated by square meters), inspection holes, measuring holes, etc. are calculated in units of pieces according to different types and specifications