SpaceAge winch type sign failures
Issued: 10/09/2019
Last Updated: 1/09/2021
Purpose
The purpose of this safety alert is to highlight the risk of winch type (wind-up) sign failure and to provide recommendations on how to avoid further incidents. This alert specifically applies to winch type signs supplied by SpaceAge Signs and supersedes all previous alerts on winch type signs.
Background
Winch type signs (refer Photograph 1 below) are used at locations such as schools, clubs, sports grounds and small businesses.
In early August 2021, the cross bar of a SpaceAge winch type sign at a Brisbane school suddenly dropped while a worker was attempting to lower it. The worker was not standing under the cross bar so was not injured, but the incident highlights the risks associated with this type of sign.
There have been a number of other incidents in Queensland where winch type signs have dropped, two of which resulted in serious head injuries. As the upper part of the signs can weigh in excess of 70 kilograms and the signs can drop rapidly without warning, fatal injuries are possible.
Over the years, three different types of fall arrest safety gear have been produced. All of these were intended to arrest the top part of the sign if the rope is cut or becomes slack. However, all three designs have been found to be unreliable, even when properly maintained.
To respond to the issue, the sign manufacturer developed a safety bracket in 2019 that has been fitted to some existing signs (refer Photograph 2). The sign involved in the August 2021 incident was fitted with the safety bracket. This bracket should prevent the sign dropping when a clutch failure occurs as it prevents the crank handle shaft from rotating. However, when the sign is raised or lowered the bracket must be removed so that the crank handle can be inserted. If the clutch fails when the crank handle is inserted, the force of the sign dropping has the potential to injure someone as the handle rotates at speed. While the safety bracket may reduce the consequences if a failure occurs, a safety risk is still present.
There are additional risks:
- during raising and lowering—anyone under the cross bar could be struck if the clutch fails
- if the winch cable breaks, the safety bracket will not prevent the sign from dropping and the different types of fall arrest safety gear may not stop the sign dropping.
At the time this alert was released in September 2021, the manufacturer and supplier of SpaceAge winch type signs was unable to be contacted by Work Health and Safety Queensland (WHSQ) and appears to be no longer in business.
Contributing factors
In the August 2021 incident, it appears that while the safety bracket was fitted, the sign was held in its raised position. However, once the bracket was removed the clutch slipped and the sign dropped rapidly before the crank handle was inserted. The fall arrest safety gear, which was meant to activate when the winch rope became slack, did not operate and the sign dropped rapidly. A WHSQ investigation was able to replicate the clutch failure with the sign dropping rapidly and the fall arrest safety gear failing to operate.
Action required
WHSQ recommends all SpaceAge winch type signs are lowered and taken out of service and should be:
- removed, or
- locked in the lowered position so that the winching mechanism cannot be operated.
Owners should ensure that appropriate control measures are in place while undertaking these recommendations.
This recommendation is made as the continued use of SpaceAge winch type signs is considered to pose a significant risk to the safety of workers, members of the public, and school children due to:
- the relative high frequency of incidents
- the unreliability and ineffectiveness of the fall arrest safety gear
- the limitations of the safety bracket while the sign is being raised or lowered
- the absence of a manufacturer and supplier to provide safety upgrades on the signs.
SpaceAge signs are normally identified with the SpaceAge branding on part of the sign, commonly on the sign’s cross bar or above. If there is any doubt about the sign manufacturer, the advice of a competent person should be obtained.
Photograph 1: Example of a SpaceAge winch type sign in the raised position.
Photograph 2: View of winch assembly with safety bracket attached and crank handle removed.