Block Selection and Application Guide
Risk Management
Comprehensive set of actions that reduces the risk of a problem, a failure, an accident
You Need:
- Product knowledge
- Application knowledge
- Manufacturer of known capability
- Products that are clearly identified with the following:
- Manufacturer’s name and logo
- Load rating or size that references ratings
- Traceability code
A Good Risk Management Program Recognizes
- Performance requirements include the following:
- Load rated products
- Quenched and tempered
- Ability to deform when overloaded
- Ability to withstand real world loading in day to day use, toughness
Mechanical Advantage and Total Load
Mechanical advantage is the leverage gained by a multiple part block. Must have a traveling block to have mechanical advantage. The theoretical advantage is equal to the number of parts of line supporting the traveling block.
| True Mechanical Advantage | Number of Line Parts |
|
|---|---|---|
| Advantage for Bronze Bushing |
Advantage for Anti Friction |
|
| 5.16 | 5.60 | 6 |
| 5.90 | 6.47 | 7 |
| 6.60 | 7.32 | 8 |
| 7.27 | 8.16 | 9 |
| 7.91 | 8.98 | 10 |
| 8.52 | 9.79 | 11 |
| 9.11 | 10.60 | 12 |
Total Load
The total load placed on the block and its end fitting determines the working load limit required.