The Port Equipment Manufacturers Association (PEMA) has published a report on crane operator health and safety, including 20 recommendations for crane manufacturers and terminal operators on how to improve rubber tyred gantry (RTG) and container crane cabin ergonomics and safety.
The paper, compiled under the auspices of PEMA’s Safety & Environment Committee, focuses on the health and safety of operators of RTG cranes and ship-to-shore (STS) container cranes.
Potential risks and measures
- High frequency vibrations on cabin and crane driver and possible disturbing noise due to vibration –> Anti-vibration systems
Cabins should be fitted with 3D high frequency antivibration dampers and brackets to improve safety, control, and maintenance access. Anti-vibration mounts should be calculated according to weight, point of gravity of the cabin and platforms, and acceleration/deceleration of the trolley.
- Maintenance and access to crane cabins –> Maintenance platforms and platforms fitted to cabins
Cranes should be fitted with a back platform for safe general maintenance of the cabin. Cabins should be fitted with lightweight platforms for maintenance, safe access, and the ability to rescue injured personnel.
- High temperatures and condensation inside the cabin
Cabins should be equipped with a split air conditioning unit to decrease noise levels inside cabins, improve comfort, maintain an inside temperature of 21°C and take fresh air supply of 50m³/h into account. Noise levels should not exceed 68 dB(A). The capacity of the air conditioning unit should be calculated on environmental temperatures, insulation of the cabin and internal heat sources. Condensation water to be drained to the outside of the cabin to prevent sight obstruction due to condensation on windows.
- Airflow from air conditioner apparatus –> Air conditioning apparatus
Main airflow not directed onto the crane driver. Direction of secondary airflow to be adjustable to improve driver comfort.
- Low temperatures inside the cabin –> Heated air flow on the main floor glass
Cabins must be equipped with heating units installed in the floor bottom, complete with thermostat with the main airflow on the main floor glass. Direction of secondary airflow to be adjustable to improve the comfort perception of the driver. Airflow strength should be appropriate to local ambient conditions; 21°C is frequently cited as a desired cabin temperature. The capacity of the heating unit should be calculated according to local ambient temperatures and insulation of the cabin. Maximum noise levels should not exceed 68 dB(A).
- Harmful emissions and pollutants –> Positive pressure and air filtration unit
Cabins should be fitted with a proven, positive pressurized air filtration system, with high efficiency particulate and gas absorbers or similar to protect drivers from harmful emissions from ships or other pollutants.
- Structural strength of glass floors –> Laminated, certified floor glass
Floor glass should be fixed, walk-on safety laminated glass, at least 40mm thick, with sliding and lockable footrest grids for optimal visibility of the working area below. Floor windows should resist a concentrated load of 2,500N/ft2, and a divided load of 1,500N/10ft2 simultaneously.
- Fall risk to drivers during operating phases due to cranes stopping suddenly –> Four-point safety belts
It is advisable to have safety belts for the shoulder and waist, so the driver is held safely during operations, and blocked in the event of the trolley suddenly stopping.
- Bending and tilting of drivers –> Safety belts
Safety belts for the shoulder and waist with type-approved roller to allow the free movement of the driver.
- Failure to monitor and control visual indicators –> Frontal positioning of visual indicators
It is advisable to install all mission-critical indicators in the lower front frame of the horizontal position, in boxes of suitable size, to avoid obstructing visibility, thereby giving drivers all necessary information, (spreader lights, container weight, container height, hoist/trim position, twist lock locked/unlocked, crane faults, windspeed, sudden high winds, overload, anti-collision alarms etc.). These are located in the driver’s main working direction, which is the look through the front and floor glass. This enables the safe control of loading/unloading operations.
- Failure to monitor and control visual indicators –> Angular positioning of visual indicators
Display screens should be positioned between 45° and 50° to drivers’ eye level while seated, ensuring the safe control of information necessary during operations.
- Difficulties related to the use and accessibility of auxiliary devices –> Lateral positioning of auxiliary devices
Auxiliary control panels and radio/transmitters should be designed according to cabin vibration; and should be placed on the right- or left-hand wall and should be within easy reach of the driver by hand when seated at the control station with a maximum rotation of the head of 90°. Main (turn on/off) switches and microphones should be positioned to allow drivers to maintain sight on driving the crane while using communication equipment.
- Failure to use touch devices, noise and vibration –> Internal noise dampers, isulation and absorption measures
No equipment installed in cabins should produce noise due to vibration of the cabin. Cabin structure and windows should be isolated to avoid unwanted noise entering the cabin. Cabins should be provided with sufficient sound absorbent material to reduce reverberation.
- Lumbar spine, neck flexion and general driver overload
It is advisable to lean the forearms while using joysticks to minimise lumbar overload. Leaning forward responsibly makes it possible to reduce neck flexion when looking downwards.
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