描述了在厚度大于等于3mm的低碳钢板上使用圆形（圆形）和方形穿孔的三种图案。孔的尺寸从125毫米到3.15毫米不等。规定了五种节距与孔距的比率，其标称开放面积约为64%至23%。

Describes three patterns using round (circular) and square perforations in low carbon steel plate of 3 mm thickness and above. The sizes of holes range from 125 to 3.15 mm inclusive. Five ratios of pitch to hole are prescribed which result in nominal open areas ranging from about 64 to 23 %.