Civil Engineering Reference
In-Depth Information
4.4.2 Manual Handling Made Easy: Barrel Handling
The work station was the wash line in a brewery where empty aluminium beer casks were received from
public houses and washed ready for reuse. Preparatory to washing the plastic keystones, the top caps,
were removed from the casks by levering out with a chisel and the shives, wooden bungs on the sides
of the casks, were removed with a hammer and chisel.
The barrels travelled along a conveyor at floor level so that the operators had to bend their backs
when manually removing the casks off the conveyor. The force and repetition needed to break and
remove the wooden shives using the hammer and chisel led to musculoskeletal shoulder
injuries. This work situation led to back and shoulder injuries and lost time for the two employees
who worked in this section of the wash line. Other employees had to work overtime to cover this
lost time.
Additionally, when the shives were removed, the wooden pieces fell to the floor forming both a trip-
ping hazard and getting trapped in the conveyor belt causing damage to the belt. When the belt was
damaged it had to be stopped. A mechanic repaired the damage and this took about 15 min for each
stoppage; on an average, a belt stoppage occurred three times each day. When this happened the rest
of the wash line, an additional nine men, were also idle.
The ergonomist measured the average elbow height of the men working there and, after allowing for
the heights of the casks, determined the most suitable conveyor belt height. Of course, the height of the
conveyor belt had to be low enough so that the keystone cap on top of the barrel could be removed and so
bending could not be completely eliminated. Other means (improved hand tools) reduced the stress on
the shoulders. Although the solutions were compromises (not ergonomically “ideal”), they have been
effective in reducing, and in fact eliminating, absence due to bad backs and shoulders. Reduced injury
resulted in reduced overtime (Table 4.2).
During the belt breakdowns not only were the two deshiving men idle but so were the nine men of the
wash line. The cost-benefit analysis model (the Productivity Assessment Tool) used here, calculated the
productive employment cost of the 11 men on the wash line and the mechanic to repair the conveyor
belt at approximately £43.00 per breakdown of 15 min. By expansion to the full year, at a rate three of
breakdowns per day and taking into account factory closures, the total cost of breakdowns is approximately
£32,000.
The ergonomics intervention resulted in improvements both in safety and productivity. Reductions in
overtime and conveyor breakdowns paid for themselves in 3 months although the benefit continued
beyond this period, which is an increase in profit.
In this case study, as well as the previous one, there were unexpected improvements in produc-
tivity beyond the immediate reason for the ergonomics intervention. In the first case, the improved
loading of the trucks and, in the second, the reduction in line breakdowns. These were not
the reasons for the intervention and were not forecast in the original assumptions made by the
management. We believe that this is a common occurrence as “good ergonomics is also good
economics.”
TABLE 4.2 Reduction in Injury Absence, Overtime, and Conveyor Belt Breakdowns
Initial Case
Improved Work Case
Total cost of employment for the deshiving area,
including overtime (£
56,400
50,400
/
year)
Cost of breakdowns (wash line idle) (£
/
year)
32,000
650
Total cost (£
/
year)
88,400
51,050
Intervention costs (£)
a
—
8,830
Savings (£
/
year)
—
37,350
Pay-back Period (months)
—
3
a
A “one-off ” cost.
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