单选:下列关于火灾自动报警系统设备检测数量要求的叙述中,正确的是()。A.各类消防用电设备主、备电源的自动转换装置,应进行两次转换试验,每次试验均

题目内容:
下列关于火灾自动报警系统设备检测数量要求的叙述中,正确的是()。
A.各类消防用电设备主、备电源的自动转换装置,应进行两次转换试验,每次试验均应正常
B.电动防火门、防火卷帘,5樘以下的应全部检验,超过5樘的应按实际安装数量30%的比例抽验,但抽验总数不应小于5樘
C.防烟排烟风机应全部检验,通风空调和防排烟设备的阀门,应按实际安装数量10%~20%的比例抽验
D.电梯应进行5次联动返回首层功能检验,其控制功能、信号均应正常
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