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Safety Alert Tower Cranes

Posted: Monday 24th, February 2014

Preventing catastrophic failure of luffing jib tower cranes in high winds

Health and Safety Executive - Safety Alert

Department Name: Field Operations Directorate/ Construction Sector
Bulletin No: FOD 2 - 2014
Issue Date: 20 February 2014

Target Audience: Tower crane owners and users, Construction, Engineering,
Entertainment and Leisure, HID, Manufacturing, Nuclear, Offshore

Key Issues: Placing luffing jib tower cranes in a safe out of service condition

Introduction:
Following the recent collapse of three luffing jib tower cranes in high winds, HSE
is making this information available to tower crane users as supplementary
guidance to that contained in BS7121 Part 5:2006, Code of practice for safe use
of cranes -Tower cranes. This information is issued without prejudice to any
ongoing investigations.

HSE is using this 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.

Background:
HSE has identified that some tower crane users have 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.

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.

Action required:
Users must

Ensure they have the most accurate, up to date information for the specific crane
they are operating by discussions or correspondence with the supplier or
manufacturer as some manufacturers have recently changed their guidance;
Check that such information includes the correct minimum out of service radius for
the specific crane they are operating with the supplier or manufacturer;
Check both after erection and periodically in service, the function of the device
that releases the slew brake and places the crane in free slew;
Check both after erection and periodically in service, that the condition of the slew
drive motors, gearboxes and slew ring bearing has not deteriorated to the extent
that the crane is prevented from slewing freely;
Check both after erection and periodically in service, the setting and function of
any devices that warn the operator that the crane jib has not been left parked at
the correct out of service radius and/or the slew brake has not been released;
Ensure that operators have been provided with instructions on how the crane
should be placed in free slew and the correct radius at which the jib should be
positioned when leaving the crane unattended. This should include measures to
routinely check that the operators understand and are following the instructions
provided;
Undertake periodic checks that the buildings under construction, other cranes or
high reach plant are not preventing the crane from free slewing. Consideration
needs to be given to both front jibs and rear counter jibs.

Relevant legal provisions:
Provision and Use of Work Equipment Regulations 1998,
Management of Health and Safety at Work Regulations 1999

References:
BS7121 Part 5:2006, Code of practice for safe use of cranes -Tower cranes

Construction Plant Hire Association guidance (www.cpa.uk.net link to external
website)

Best Practice Guide – Maintenance, Inspection and Thorough Examination.
Tower Crane Operator’s Handbook
Tower Crane Out of Service Wind Speeds
Leaving Tower Cranes Out-of-Service When Other Cranes Are Working on Multiple
Tower Crane Sites.

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