Make up air for high CFMrangehood(补充说明)

Make up air 对于风量高于400 CFM 的抽油烟机在2009IRC(2009国际民居规范）中规定如下：

M1503.4 Makeup air required. Exhaust hood systems capa- ble of exhausting in excess of 400 cubic feet per minute (0.19 m3/s) shall be provided with makeup air at a rate approximately equal to the exhaust air rate. Such makeup air systems shall be equipped with a means of closure and shall be automatically controlled to start and operate simultaneously with the exhaust system. 

这里没有要求不如空气必须预先加热或制冷。

这里需要理解的问题是，大抽风量造成的室内空气负压可能有什么危害。通常并不是担心缺氧，而是担心负压导致空气从烟囱倒流。极端的例子是，曾经有报道表明，大风量抽油烟机可能造成烟囱倒灌，甚至于，让壁炉中的火焰冲出壁炉，朝向室内，有严重的火灾危险。