skip navigation
Home >  WorkSafe >  Additional safety topics >  Plant and machinery >  Frequently asked questions >  Tractor cranes - safe handling of loads

Tractor cranes - safe handling of loads

Contents

  1. Introduction
  2. Fatal accident
  3. Safe work practices
  4. Taglines essential
  5. Pre-warning bumper 

1. Introduction

In recent years several serious accidents have occurred when a dogman has stepped between a mobile crane and its suspended load.

Because boom supports and hydraulics are often located in front of the crane driver's cabin, the driver may at times lose sight of the doggers. This is when accidents can happen.

The aim of this pamphlet is to point out ways of avoiding such accidents and is directed towards:

  • crane owners;
  • crane drivers;
  • doggers; and
  • work supervisors.

Consultation and co-operation between these people must be the key to all safety and health matters in the workplace.

The Occupational Safety and Health Act 1984 says employers and employees should meet to discuss hazards and formulate practical and effective safety and health standards, and together put these into practice.

The Act entitles employees to elect safety and health representatives to represent them during these discussions.

Consultation should include discussions on workplace equipment, work procedure, work design and long term planning. The information in this pamphlet should help these discussions.

The following accident report demonstrates the need for safe work practices.

2. Fatal accident

At a materials and equipment storage area in metropolitan Perth, a crane driver and a dogger were working together to relocate some items.

Each held appropriate certificates of competency, were well experienced, and were working with a tractor crane which was in good mechanical condition.

The accident occurred when a building truss was being moved to a storage area. The truss was symmetrical in shape and correctly suspended by a two-leg sling. The dogger was walking in front of and outside the path of the crane, adjacent to the end of the truss, when the truss swung inwards. To control the truss, the dogger apparently considered it necessary to walk in line with the left hand crane wheel. In this position he was obscured from the driver's sight by the crane frame and luffing ram.

Though the crane was moving slowly, the dogger was overtaken and pushed to the ground. The front wheel ran over part of his legs and body. The dogger died from his injuries.

This was one of many similar mobile crane accidents reported to the WorkSafe Western Australia in recent years.

3. Safe work practice

Safe work procedures require the dogger to be clear of trapping spaces between moving loads and fixed structures or machinery.

There can be problems, especially with awkward loads, and for such loads, taglines must be used.

Taglines should always be provided as a standard part of a crane's lifting equipment. They are essential for controlling awkward loads and maneuvering them into difficult positions.

If a load is to be transported over a distance, taglines should be used to tie the load back to the crane to reduce swing or rotation.

If a dogger is required to restrain a load during transit, the dogger should be out beyond the load, using a tagline, and be in constant view of the crane driver.

  1. The preferred option: Securing the load with taglines enables the dogger to remain clear of the moving crane and well forward of the load.
  2. If it is necessary for the dogman to guide, he should be positioned well away from the wheels of the tractor crane.
  3. When guiding a load, the dogman should remain clearly visible to the driver at all times, and not be hidden by boom supports.

4. Taglines essential

Driver and dogger should discuss their intended work pattern before each job begins, and during lifts the dogger should give clear hand signals that conform to the requirements of AS2550.

Employers of crane operators have a duty under the Act to ensure employees are informed of hazards and are adequately trained.

5. Pre-warning bumper

The area between a suspended load and the crane wheels is a prohibited zone, where no person should ever walk or stand.

However, as an added precaution to reduce chances of a dogger being injured, owners should consider attaching to the front of all tractor cranes a pre-warning bumper as illustrated in the following diagram.

This additional safety feature in no way changes the safety procedures described. WorkSafe recommends that a pre-warning bumper be fitted to all tractor-based, tractor-connected and tractor-mounted mobile cranes.

A guard structure is bolted to the axle to eliminate transverse welds. The centre of the axle and bumper are on the same level.

  1. Bumper length: Equals overall width of crane, plus 50 mm.
  2. Flap Width: Equals tyre width + 25 mm.
  3. Bumper material: 75 mm nom. bore pipe or 127 mm x 64 mm R.S.C.
  4. Flap material: 12 mm thick conveyor belting.

Related information