To test this, the operator may use the glass and air space thickness scale, or use the ASTM standards indicator which is located on both the top and bottom of the Overall IG Unit Thickness scales.

• 测量时，操作员可以使用玻璃和间隔距离的刻度，或者使用ASTM标准指示器，它位于IG全厚刻度的顶部和底部。