A General Idea Indicating The Safe Working Loads Of Our Blocks
| Dia. of Sheave Circumference of Rope |
6”
1”-1¼” |
7”
1¼”-1½” |
8”
1½”-1¾” |
10”
1¾”-2¼” |
12”
2¼”-2½” |
14”
2½”-3” |
16”
3”-3½” |
18”
3½”-4” |
|
| S.W.L tons | Single Sheave | 0.75 | 1.5 | 2 | 3 | 5 | 6 | 7 | 10 |
| Double Sheave | 1 | 2 | 3 | 5 | 8 | 10 | 15 | 20 | |
| Triple Sheave | 1.5 | 2.5 | 5 | 10 | 12 | 15 | 20 | 25 | |
| Dia. of Sheave Circumference of Rope |
6”
1”-1¼” |
7”
1¼”-1½” |
8”
1½”-1¾” |
10”
1¾”-2¼” |
12”
2¼”-2½” |
14”
2½”-3” |
16”
3”-3½” |
18”
3½”-4” |
|
| S.W.L tons | Single Sheave | 0.75 | 1.5 | 2 | 3 | 5 | 6 | 7 | 10 |
| Double Sheave | 1 | 2 | 3 | 5 | 8 | 10 | 15 | 20 | |
| Triple Sheave | 1.5 | 2.5 | 5 | 10 | 12 | 15 | 20 | 25 | |
Safe Working Loads (S.W. L.) Of Rigs B. S.: 4018-1966
|
Dia. of Sheave
|
Dia. of Rope |
S.W. L.
per Single part of rope Ton |
Safe Working
Loads of Rigs
|
||||||
| inch | mm | inch | mm | 1/1 Rig Ton | 2/1 Rig Ton | 2/2 Rig Ton | 3/2 Rig Ton | 3/3 Rig Ton | |
| 5 | 127 | 3/8 | 9 | 0.75 | 1.5 | 2.25 | 3.0 | 3.75 | 4.5 |
| 6 | 152 | 7/16 | 11 | 1.0 | 2.0 | 3.0 | 4.0 | 5.0 | 6 |
| 7 | 177 | 1/2 | 13 | 1.25 | 2.5 | 3.75 | 5.0 | 6.25 | 7.5 |
| 8 | 203 | 9/16 | 14 | 1.75 | 3.0 | 4.50 | 6.0 | 7.40 | 9.0 |
| 9 | 228 | 5/8 | 16 | 2.0 | 4.0 | 6.0 | 8.0 | 10.0 | 12.0 |
| 11 | 279 | 3/4 | 19 | 3.0 | 6.0 | 9.0 | 12.0 | 15.0 | 18.0 |
| 12 | 304 | 7/8 | 22 | 4.0 | 8.0 | 12.0 | 16.0 | 20.0 | 24.0 |
Selection Criteria: Sheave Dia/Rope Dia = At least 12
The safe working load per single part of rope is approximately one sixth of the nominal breaking load of ropes as 2 2 specified in B.S.302 621 in the 6 x 37 group of tensile strength 100/110 ton / inch (160/175 kgf/mm ). This is the nominal breaking load on which the design of blocks to this standard is based.
The manner of test laid down in schedule II of DOCK Workers (Safety, Health, and Welfare)Regulations, 1990, is as follows:
Article of Gear
Single sheave pulley block
Multiple sheave block with safe working load up to and including 20 tons
Multiple sheave block with safe working load over 20 tons up to and including 40 tons
Multiple sheave block with safe working load over 40 tons
Proof Load
Four times the safe working load
20 tons in excess of the safe working load
One and a half times the safe working load