<span style='display: inline !important; float: none; background-color: transparent; color: rgb(0, 0, 0); 微软雅黑","helvetica neue","hiragino sans gb"; font-size: 14px; font-style: normal; font-variant: normal; font-weight: 100; letter-spacing: normal; orphans: 2; text-align: left; text-decoration: none; text-indent: 0px; text-transform: none; -webkit-text-stroke-width: 0px; white-space: normal; word-spacing: 0px;'>正偏差
测量挡烟垂壁边沿与建筑物结构表面的最小距离，此距离不得大于20mm，测量值的允许正偏差不得大于规定值的5%。故选。