ring sizing charts 4a
 ring sizing charts 4b
18" x 24" Manhole Rings 3/4" thick as manufactured by the Los Angeles Boiler Works, Inc. have sufficient depth if dimensions 'A' & 'B' are not less than indicated on the chart for thickness & radius of heads and diameter of shell. Reinforcement of openings should be calculated for each application.
.
Shell
or
Head
Thickness
Shell
Dia.
48"
54"
60"
72"
84"
96"
108"
120"
Over
132"
Head
Radius
24"
27"
30"
36"
42"
48"
54"
60"
Over
66"
S.E.
Heads
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48"
54"
60"
72"
Over 
84"
Dim.
'A'
Dim.
'B'
Dim.
'B'
Dim.
'B'
Dim.
'B'
Dim.
'B'
Dim.
'B'
Dim.
'B'
Dim.
'B'
Dim.
'B'
3/16
1/2
6
6
6
6
4
4
4
4
4
1/4
5/8
6
6
6
6
4
4
4
4
4
5/16
13/16
6
6
6
6
4
4
4
4
4
3/8
15/16
6
6
6
6
4
4
4
4
4
7/16
1-1/8
6
6
6
6
6
6
4
4
4
1/2
1-1/4
6
6
6
6
6
6
6
4
4
5/8
1-9/16
7
7
6
6
6
6
6
6
4
3/4
1-7/8
7
7
6
6
6
6
6
6
4