Thickness

Weight

Inches

Millimeters

Pounds/Square Foot

0.0156

0.369

1

0.0312

0.792

2

0.0625

1.550

4

0.1250

3.180

8

0.2500

6.350

16

0.5000

12.700

30

Minimum thickness of Lead

Weight per Square Foot in Pounds

Millimeters (mm)

Inches

75 kV

1.0

0.039

2-1 / 2

100 kV

1.5

0.059

4

125 kV

2.0

0.079

5

150 kV

2.5

0.098

7

175 kV

3.0

0.118

8

200 kV

4.0

0.157

10

225 kV

5.0

0.197

13

300 kV

9.0

0.354

24

400 kV

15.0

0.591

38

500 kV

22.0

0.369

56

600 kV

34.0

1.343

81

900 kV

51.0

2.000

120