Information on this page is drawn from "Ladle Relining Lift Equipment-Ergonomic and Technical Design Considerations" published by Kelly S. Chadwick and Gary G. Royer

Work Platform Options for Ladle Rebricking

Consideration of the work platform options should be made since the position of the mason relative to both his bricks and to the wall he is building has a direct impact on the amount of bending and lifting required.

Stationary Work Platform/ Scaffolding/ Pies

Stationary work platforms are placed by crane within the ladle one atop another throughout the rebricking process to periodically raise the level of the refractory mason(s). Time must be spent removing all materials and allowing personnel to exit via ladder each time an additional platform is added to the stack.

Figure 1 Photo of stacks of stationary "pies" in foreground and stationary brick pallet tables in background

Powered Lift Devices

Once the floor and bottom rows of bricks have been placed within the ladle, a powered lift device can be lowered into the ladle by overhead crane. The ladle relining lift can be quickly repositioned by the worker at any time to maintain an optimal ergonomic working position. Ladder use, and therefore the potential for falls, is greatly reduced since the lift can be easily raised to allow personnel to exit or enter the working area. A secondary pallet lift can also be loaded onto the primary lift to adjust the pallet of refractory brick so that it too remains at an ergonomically desirable height.

Figure 2 Example of collapsed ladle lift with secondary lift in raised position on top

Support for Powered Lift Devices

A key recommendation by both OSHA5 and by the Construction Safety Association of Ontario2 to help combat lower back MSDs is the use engineering controls such as lifts or automated materials handling equipment. A powered lifting platform can help to keep the work area of the mason positioned roughly waist level where minimal movements in both the back and arms are required.

In a study of bricklaying ergonomics in the construction industry, the "wrist/hands to elbows" zone was identified as being the one where bricklayers were at their most comfortable and productive. The study included the use of both questionnaires and an experiment to measure actual productivity at different working heights. The study found that maximum bricklaying productivity occurred from a height of 1'4" above the work platform to 4'0".

In several government sponsored studies, powered lift devices have been found to be beneficial for bricklayers in both the construction and steel industries. An ergonomic demonstration project was undertaken by Spilker Masonry in Spokane, Washington in 2001 to find ways to prevent MSDs in construction masons. One control that they researched was a comparison of hydraulic powered scaffolding vs. standard scaffolding. Spilker found that powered hydraulic tower scaffolding not only kept bricklayers at optimal ergonomic laying height but also increased productivity by 20%.

In the steel industry, a follow-up ergonomics evaluation following the implementation of ladle relining lifts at Cascade Steel in Oregon found that a comparison between pre and post project employee discomfort surveys indicated a 32% decrease in overall refractory bricklayer discomfort levels and slightly increased production efficiencies.

To substantiate this finding among additional purchasers of ladle lift equipment, a small, informal survey of ladle lift purchasers was undertaken by the authors of this paper. The answers indicate that the primary benefits of using such lifts were reduced ladderwork and risk of injuries. Employee morale among brickers was also noted as being "somewhat increased" to "greatly increased" in all plants where ladle lifts had been introduced.

Additionally, a small powered lift table placed on top of the platform lift may be helpful in keeping the mason's supply of bricks at an optimal ergonomic height. In a study of masons in the construction industry in Ontario, the recommendation was that the minimum height for platforms of brick should be knee-level to reduce the amount of forward bending. The same study found that bricklayers (working without the benefit of a brick lift) often bend forward more than 1,000 times per shift.

Ladle Lift Design Process Considerations

Since it is recommended that the platform of a ladle relining lift be custom designed to match the size and shape of the ladles being serviced, a basic design and approval process should be followed by both the purchaser and the lift manufacturer. The first step in this process is for the client to supply drawings of both the empty ladles and the ladles with refractories to the lift manufacturer. The empty ladle drawings should be provided since they reveal the accurate location of all well blocks and slide gates in the ladle bottom. The lift should be designed to straddle these openings. The refractory drawing should be provided so that the lift manufacturer can provide approval drawings which show the ladle lift within the refractory lined ladle.

The manufacturer should then provide drawings back to the purchaser for final approval of the lift's design. The drawing(s) should show lift within actual lined ladles to ensure accuracy of form, fit and function. The drawing(s) should indicate the tare weight of the lift to allow the client to verify that their overhead handling capabilities are adequate to the task. Purchasers at this point may wish to fabricate a mock-up of the lift platform in wood or another substance to physically place within their ladles prior to final approval of the design. Although this is an optional step, it helps to avoid the problem of ladle lifts being built to suit dimensions that may have been inaccurately recorded on the purchaser's original ladle drawings.

Concluding Remarks

With increasing employee and industry pressures to implement ergonomic solutions for labor intensive tasks that are prone to generating lost time injuries, powered lift solutions for ladle relining activities in the steel industry have been gaining popularity. A review of the scientific and technical papers on the subject of bricklayer ergonomics supports the use of adjustable work platforms, specifically for keeping masons at an ergonomic working height during the bricking process. A layman's guide to the design and process considerations for powered ladle relining lifts was provided to assist the steel industry in making an informed purchase for this specific bricking operation.

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Ladle Relining Lift Equipment-Ergonomic and Technical Design Considerations