The HSE said that it was using the alert to remind those who operate tower cranes that when left unattended in the out-of service condition, luffing jib cranes must be in free slew with the jib at a safe out-of-service radius. The governmental body believed that some tower crane users had not been releasing the slew brake and/or placing the jib at the correct out of service radius, when leaving cranes out of service and unattended.

The organisation explained that if luffing jib cranes are left out of service with the slew brake engaged and/or the jib parked at too small a radius, there is a possibility the crane may not be able to weathervane freely in high winds. This could result in very high loadings being placed on the crane with the consequential collapse of the jib or the whole crane.

The safety alert requires those using tower cranes to ensure that they have all the most accurate and up to date information on the tower crane that they are using from the manufacturer. It also states that the technical functions of the cranes should be checked periodically in service.

The full guidance is available at: http://www.hse.gov.uk/safetybulletins/luffing-jib-tower-cranes.htm