Workshop and warehouse hazards include the safe operation of overhead cranes to transport materials and heavy component loads. Ensuring complete and constant visibility of the load by the crane operator can be an issue and in these cases a spotter is required to guide the lift. In these circumstances, the crane-operator is subject to a high level of stress, as he/she has to trust in the judgment of others in order to carry out an operation for which he/she is responsible. Crane operations that see a loss of visibility by the operator is one of the main causes of incidents and accidents when performing a lift. Distractions, poor communication, inexperience, noisy environments and so on, make crane operations high-risk warehouse hazards. This post looks at recent research investigating the risk indicators for safety performance of crane-operations, safe lifting capacity guidelines and the impact of using a visual guidance system to monitor lifting operations. The paper looks at leading and lagging indicators for lifting and handling operations through the lens of a chemical accident case study.
Chemical warehouse crane accident
In Texas, in 1987, a crane accident occurred that caused the release into the atmosphere of hydrofluoric acid. More than 800 people were sent to the hospital due to breathing in the toxic fumes. The crane was lifting a component weighing several tons that was accidentally dropped onto the top of a hydrofluoric acid storage vessel. This facility was being moved for repair and maintenance during a general plant turnaround. The dropped component severed a 100mm acid loading line and a 30mm pressure relief line causing the hydrofluoric acid to be released.
The accident was investigated by OSHA, which concluded that various causes contributed to the accident:
- a failure of engineering control measures to prevent the chemical release (i.e. emptying hydrofluoric acid vessel before hoisting a heavy load over it and not hoisting a heavy load over a hydrofluoric acid tank);
- the crane was not correctly blocked or secured (wooden blocks supporting crane outriggers were crushed);
- crane inspection documentation was not prepared; and
- the crane safety devices were not inspected prior to use and a malfunction occurred.
It is likely that the crane operator decided to drop part of the moving system, in order to avoid a major accident. However, he had limited visibility and no spotter to guide him and he dropped the load in the wrong place. The research argues that a visual guidance system could have been helpful in this case. Such a system would have assisted the crane-operator in the navigation of the load by indicating where he should have dropped it to avoid the major catastrophe that the accident caused.
Safe lifting capacity guidelines when using a crane
Visibility of the moving load at all times, and adhering to carrying loads of the correct size and weight, are highly important when undertaking crane lifting operations. All cranes should have a crane-specific load chart or rated capacity chart that sets out how the crane lifting capacity varies depending on how the crane is set up.
Safe Work Australia advises that load charts should include enough information to identify the crane configuration it applies to. For example:
- the safe working zone
- the counterweight mass
- whether a fly jib is fitted, in use, in place or stowed
- outrigger extension or pick-and-carry mode
- maximum speed for mobiling a load
- rope and reeving details, including number of falls of rope in the hook block
- main or auxiliary hoist in use, and
- whether the hook block is included or excluded.
When reading load charts, it is important to subtract the mass of the hook block and lifting slings from the capacity of the crane at the particular radius. Crane operators should ralso remember to subtract the mass of the fly jib from the capacity of the main hook, when lifting from the main hook, on the main boom with a fly jib attached to the boom head. This should be noted on the load chart.
How can we effectively train about warehouse hazards?
The case study reveals what can go horribly wrong when working with cranes and lifting activities. Risk assessment, safe operating procedures, safe work instructions, job safety analyses, safe systems of work and so on, help to mitigate the risks. Documenting lifting procedures is a first safe step to ensure that all risks are recognised and may include:
- the hazards and risk controls to be applied
- the type of crane or cranes to be used
- the loads to be lifted including the mass of the lifting equipment e.g. slings and spreader beams
- the position of the crane, loads to be lifted and where
- the load working radius range with confirmation the loads are within the crane’s capacity at the maximum radius
- when a spotter is needed
- the slinging and lifting sequence
- the rigging requirements of the job.
However, all of these require training and this training needs to be delivered in an engaging, holistic and relatable way. Effective training is a way to provide direction and understanding of safe operating procedures, hazards and critical control measures.
Tap Into Safety has interactive Workshop safety training modules which include detailed education on cranes and lifting activities. These safety training modules can be completed in 15 minutes and can easily be added to your existing induction, on-boarding and refresher training modules via a simple URL integration.
The training modules show a 360-degree panoramic photo of typical mechanical and maintenance workshops. Not only do they both cover cranes and lifting activities, they also train on a variety of major hazards and risky behaviours that can occur in a workshop environment. Some of these include:
- Manual Handling
- Slips and Trips
- Working around suspended loads
- Various plant operation
- People and plant interraction