与插入地面灭火设备喷嘴的开口有关。如果提供一个或多个开口，其形状应为圆形或方形，尺寸如下:圆形；直径应为最小10O mm至最大13O mm；广场正方形的边应为最小10 mm至最大13 mm。

Relates to openings for the insertion of the nozzles of ground fire extinguishing equipment. If one or more openings are provided, they shall be either round or square in shape and of the following dimensions: Round; the diameter shall be from 1OO mm minimum to 13O mm maximum; Square; the sides of the squares shall be from 1OO mm minimum to 13O mm maximum.