May 2019

Electronic Controls: To Upgrade, or not?

A B77 “interpretation” encourages resorts to upgrade electronic controls on older chairlifts.

Written by Mike Lane | 37 Views | 0 comment

This dive into the ANSI B77.1 Standard deals with Annex J and the requirements for safety functions on newly-installed and relocated lifts.

These functions—such as emergency shutdowns, reverse rotation detection, and tension system variations—should be held to a rigorous standard, as they are often fail-safe controls that prevent incidents such as mechanical malfunctions and passenger injuries. The standards in Annex J are important for ensuring the safe operation of our aerial ropeways, and engineers are required to sign off that these requirements and standards have been met.

Annex J also outlines the risk analysis process for safety-related control function performance. This analysis takes into account the frequency of certain events, the likelihood that the event will cause injury, and the severity of the potential injury. The manufacturers of safety control systems are tasked with performing an analysis of the risks, hazards, and problems that each safety system is trying to protect against.

Because of the importance of these safety controls, the newest B77.1 standard, adopted in 2017, requires that electrical control upgrades must meet the latest design standards. As it’s written, Annex J appears to mandate upgrading of the electronic controls for older lifts; however, this was not the intent of the language. This wording in the newest B77.1 standard may be preventing many from actually upgrading, or modifying machines due to the added costs, complexities, and analysis.

In a nutshell, your retrofitted lifts don’t need to adhere to Annex J, but it is a good guideline for analyzing the importance of how your safety controls should function.

Because of the confusion about this, the ASC B77 committee, in spring of 2018, approved a new interpretation of the standard. The interpretation states, “It is not the intent of the modification wording to require that modifications of and to the electrical controls be designed in accordance to ‘Annex J’.” This change will be published as an addendum to ANSI B77.1, hopefully in 2020.

Upgrading an older lift can make use of new technologies and modern design techniques. Let’s say you’re trying to upgrade the electrical control system on a lift built in 1965. Electrical control circuits allow the lift to be operated (started, run at speed, and stopped) as well as monitor and control the critical safety functions of the lift.

The idea of upgrading these control functions to something more modern can be beneficial, and is encouraged by the B77 Standards Committee when it makes sense, though it’s recognized that the “Industrial Standards” for risk analysis don’t always fit so nicely when looking at old equipment. The manufacturer of the old lift may no longer be in business, complicating the ordering of parts and/or requiring special fabrication from another company.

Upgrading lift electronics is a positive step, and the B77 committee wants to make it as easy for resorts as possible. To reiterate: Your retrofitted lifts don’t need to adhere to Annex J, rather it’s a good guideline for analyzing the importance of how your safety controls should function.