TOWER CRANE SAFETY GUIDELINES

Tower cranes and lifting operations

Tower cranes with fixed jib are commonly used in building sites. Accidents involving tower cranes as well as mobile cranes are not uncommon. Following the

introduction to amendment legislation and code of practice in recent years, coupled with considerable effort in education, training, publicity, and certification of workers, the number of fatal accidents has decreased sharply.

The causes of tower crane and mobile crane accidents are quite varied. Most tower crane accidents happened during the erection, climbing (up and down) and

dismantling. The term “climbing” with respect to tower cranes is the process

whereby an entire crane is raised on or within/outside a structure that is under

construction. It generally refers to changing the height (up or down) of fixed tower cranes. Climbing of tower crane is more accident-prone.

Mobile crane accidents are mainly due to overturning, failing of jib as a result of

unauthorized assembly or modification of the lattice not according to the

manufacturer’s specifications or misuse by crane personnel or operator, e.g. using the crane’s counterweight instead of a vibrator to pull sheet piles, thus causing the mobile crane to tip forward.

Another common cause is overloading due to unauthorized defeat or alteration of the automatic load sensing device. In March 1999, a newly commissioned heavy-duty truck-mounted hydraulic crane at a marine base suddenly overturned while in operation, leading to the death of a marine police officer.

Accidents can happen to mobile cranes engaged in large-scale foundation work as a result of the collision of jibs resulting in the cranes overturning.

Statutory requirements on the tower and mobile cranes are clearly laid.The purpose is to assist duty holders to comply with the provisions of the Construction Sites (Safety)

Regulations and the Factories and Industrial Undertakings (Lifting Appliances and

Lifting Gear) Regulations. These guides provide guidance on the safe application

and operation of mobile cranes and tower cranes to ensure the safety of employees working at or in close proximity to a moving crane.

Apart from the general requirement of a safe system of work which should cater for the safe lifting operation and the safety of non-operators, the Code also provides guidelines regarding the safe distance between the crane in operation and other non-operators in different situations.

The Code addresses in detail the following issues –

▪ Management of the lifting operation

▪ Planning of the lifting operation

▪ Responsibilities/requirements of personnel

▪ Selection of tower cranes

▪ Markings and documentation

▪ Operation features of tower cranes

▪ Siting of tower cranes

▪ Erection and dismantling

▪ Procedures and precautions

▪ Safe working loads and operating conditions

▪ Maintenance

▪ Inspection, examination, and testing

▪ Securing of loads before lifting

▪ Recommended hand signals

▪ Frequency of test, thorough examination, and inspection of tower cranes

under LALGR

Apart from statutory requirement and the Code, the industry has in recent years

successfully developed a number of good safety practices to enhance the safe use of tower cranes and lifting operations:

Adjustment and maintenance

For adjustment or maintenance to be performed safely, some improvements have

been devised (apart from the standard design by the manufacturer) on access

walkways, handholds, footholds, safety lines, or other safeguards as necessary to

eliminate the hazard of falling from a crane.

Safety devices and signaling aids.

The development and implementation of additional active systems which prevent

cranes from exceeding their safe performance envelope have contributed to

significant decreases in the number and severity of crane accidents by minimizing the opportunity for human errors. These safety devices include CCTV, anti-collision device (to prevent overlapping loads and collision of jibs of cranes), wind speed detection device, visual warning devices, audible signals and automatic stops, which operate in relation to rated loads, limit devices, and constant pressure control devices

Characteristic of the system:

▪ The system capacity is up to 20 cranes on a single site with 5 cranes

operating in the same working area works. It works with a pre-set working

zone for each tower crane

▪ Defines restricted zones e.g. above site office, bridges or roads

▪ Allows operation at maximum safe speed with smooth stoppage

▪ Computerized indicator in cabin can show approach of other cranes

▪ Radio communication can be wired or wireless.

General Safety hints for cranes and lifting operation:

▪ Plant and equipment in good condition

▪ Daily safety inspection procedures/checklists

▪ Fault reporting/rectification system in use

▪ Operators trained and licensed

Warning and instructions displayed

▪ Warning lights operational

▪ Reversing alarm operational

▪ Satisfactory operating practices

▪ Fire extinguisher

▪ Tyres in place working satisfactorily

▪ Safe Working Load of lifting or carrying equipment displayed

▪ Permit to work or lifting certificate for heavy and/or complicated operation

(practiced in West Rail Projects and projects with extensive heavy lifting or

civil works)