In his latest Elevator World article, Colin Craney takes a deep dive into the often overlooked but vitally important topic of rope-specific pressure in lift traction systems.
The piece, titled “Rope-Specific Pressure”, challenges a prevailing assumption in the industry that because the current standard (EN 81‑20) no longer explicitly prescribes rope pressure, it can be ignored.
Craney observes:
“This is the second occasion on which I have encountered the dubious proposition that ‘as a measure of rope pressure is no longer prescribed in EN 81, it therefore need not be considered.’ … In both of these instances, the maximum permissible pressure was exceeded by a significant margin.”
He also issues a strong warning:
“Excessively high rope pressures … represent no more than a reduction in capital cost at the expense of an unknowing future user and/or maintainer to whom the duty to, and cost of, managing the risk … is transferred.”
Throughout the article, Craney assesses how the historical method of calculating rope-specific pressure (from the work of Hyman Hymans and Heilborn Heilborn) remains relevant even though modern standards focus more on fatigue-based safety factors.
He highlights how neglecting rope pressure, especially in modern machine-room-less (MRL) configurations with smaller sheaves and complex roping arrangements, can compromise safety, performance, and long-term resilience.
In short, Craney assesses not just the design tools and standards, but the engineering ethics and practical risk transfer hidden behind compliance language. It’s a timely call for traction system designers, consultants and specifiers to revisit assumptions, prioritise robust design and reject cost-driven shortcuts.
Read more here – Click the image to read the full article
