Using pulleys with small-diameter rope or cord.
Product Information and Specifications
As part of their certification as PPE, Petzl pulleys are compatible with ropes greater than 7 mm in diameter. The use of thinner cords may be possible.
Warning
- Carefully read the Instructions for Use referenced in this Tech Tip before reading the Tech Tip itself. You must have read and understood the Instructions for Use to understand this supplementary information.
- Performing these techniques requires specific training. Work with a professional to confirm your ability to perform these techniques safely and independently before attempting them unsupervised.
- We provide examples of techniques related to your activity. Other techniques not described here may also exist.
The EN 12278 standard does not require setting a minimum diameter limit for compatibility with pulleys. However, Petzl pulleys show compatibility only with diameters greater than 7 mm, regardless of the type of cordage (cord, dynamic rope, low-stretch rope, static rope...).
Using cords in pulleys is common: accessory cord in a double mariner pulley system, various haul systems, hauling or rescue with PUR LINE and RAD LINE...
Some pulleys have a space between the sheave and the side plates, where a thin cord can jam in case of an off-axis pull. So they are not compatible with small-diameter cordage. Some pulleys can be used with small-diameter cords, except in certain cases (see table below). The smaller the cordage diameter, the greater the risk of derailment, especially with diameters less than 5 mm. Always heed the use and strength limits of the cord, indicated in its Instructions for Use and/or the manufacturer's directions.
Pulleys that are physically compatible with cordage of less than 7 mm in diameter.
Pulleys that are compatible only with the cordage indicated in their technical notice (non-exhaustive list)
