TM 5-805-12
Table 4. Lead shielding conversions.
APPROXIMATE WEIGHT
THICKNESS
3
MILLIMETERS
INCHES
DECIMAL INCHES
POUND/FT
0.20
1/128
0.0078
0.5
0.40
1/64
0.0158
1.0
0.60
3/128
0.0234
1.5
0.79
1/32
0.0313
2.0
1.00
5/128
0.0391
2.5
1.19
3/64
0.0469
3.0
1.39
7/128
0.0547
3.5
1.58
1/16
0.0625
4.0
1.98
5/64
0.0781
5.O
2.38
3/82
0.0938
6.0
3.17
1/8
0.1250
8.0
3.97
5/32
0.1563
10.0
4.76
3/18
0.1875
12.0
5.56
7/32
0.2187
14.0
6.35
1/4
0.2500
16.0
7.14
9/32
0.2813
16.5
7.94
5/16
0.3125
18.0
8.47
1/3
0.3333
20.0
8.73
11/32
0.3834
20.5
9.53
3
0.3750
22.0
10.76
2/5
0.4000
24.0
11.11
7/16
0.4375
26.0
12.70
1/2
0.5000
30.0
14.29
/16
0.5625
33.0
15.88
5/8
0.6250
37.0
16.93
2/3
0.6667
40.0
17.46
11/16
0.6875
41.0
19.05
3/4
0.7500
45.0
20.64
13/16
0.8125
48.0
22.23
7/8
0.8750
52.0
23.81
15/16
0.9375
55.0
25.40
1
1.000
60.0
Source: Management and control of Diagnostic X-Ray, Therapeutic X-Ray, and Gamma-Beam equipment, TB MED 521.
bonded under pressure to plywood, gypsum plaster lath, gypsum wall board, aluminum, or steel. Lead panels can be
fastened with common nails or common screws that are covered with a lead tab, grommet, and/or a lead disk depending
on whether the studs or furring strips are wood or metal. See figure 1 for details.
a. Lead-lined wallboard. Lead-lined wallboard consists of a sheet of unpierced lead laminated to gypsum
wallboard. The standard wallboard size is 1/2 or 5/8 inch thick, 48 inches wide, and 96 inches long. See figure 2 for
jointing details.
(1) Pilot holes for lead-headed nails are predrilled or field drilled as necessary to prevent deformation of the
lead-headed nail and distortion of the wallboard.
(2) Wallboard is applied with long edges parallel to supports and with lead linings placed next to supports.
Blocking is provided at end joints. Sheet-lead strips not less than the thickness used on the wallboard and not less than 1-
1/2 inches wide are installed on blocking and supports where joints occur. The lead strips are secured to blocking and
supports with wire nails at outer edges of strips. Edges of the wallboard are butt-jointed and nailed to supports with nails
at approximately 8 inches on centers at joints and 12 inches on centers at intermediate supports. The nails are driven
slightly below the surface of the wallboard and then covered with a 5/16-inch diameter lead disk. Lead disks are covered
by tape or spackling to hold them in place.
(3) When using screws to attach wallboard to metal studs, they must be 1 inch long and used at the edges of
the board. Heads of screws are covered with a 1/2-inch diameter lead disc cemented to wallboard and made flush with
the surface of the wallboard.
(4) When using two layers of wallboard, the finish ply is to be bonded to the first ply with a laminating adhesive
that is applied following the manufacturer's recommendations. First ply of wallboard is nailed to supports with a nail
covered with a 5/8-inch diameter lead disk. Nailing of the finish ply will not be permitted. A shoring system will be used to
hold the finish ply in place until the adhesive dries; a minimum of 24 hours.
1-6
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