ring sizing charts 2a
 ring sizing charts 2b

 
12" x 16" 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.
30"
36"
42"
48"
54"
60"
66"
72"
Over
72"
Head
Radius
---
18"
21"
24"
27"
30"
33"
36"
Over
36"
S.E.
Heads
---
---
---
30"
---
36"
---
42"
Over
42"
Dim.
'A'
Dim.
'B'
Dim.
'B'
Dim.
'B'
Dim.
'B'
Dim.
'B'
Dim.
'B'
Dim.
'B'
Dim.
'B'
Dim.
'B'
3/16
1/2
4
4
3
3
3
3
3
3
3
1/4
5/8
4
4
3
3
3
3
3
3
3
5/16
13/16
5
4
4
4
3
3
3
3
3
3/8
15/16
5
4
4
4
4
4
3
3
3
7/16
1-1/8
5
5
4
4
4
4
3
3
3
1/2
1-1/4
5
5
4
4
4
4
4
4
3
5/8
1-9/16
6
6
5
5
4
4
4
4
4
3/4
1-7/8
6
6
5
5
5
5
4
4
4