Concern details
Task description:
Courier
drivers
are
required
to
deliver
and
load
packages
through
the
rear
door
of
the
truck
numerous
times throughout
the
day
(up
to
80
times
in
a
shift).
Forces
to
open
the
rear
door
range
from
5
–
32
kg
(average
19
kg) and
the
forces
to
close
the
rear
door
range
from
7
–
26
kg
(average
16
kg).
The
forces
to
open
and
close
the
door are
greater
when
the
springs
wear
out
and
the
door
is
poorly
maintained.
The
handle
height
of
the
door
is
floor level
when
in
the
closed
position
and
at
200
cm
when
in
the
open
position.
Evaluation:
The
vertical
heights
result
in
awkward
postures
including
bending
and
overhead
reaching.
The
rear
doors
are opened
and
closed
using
one
hand,
while
the
opposite
hand
may
be
used
unlock
the
latch.
The
forces
to
open
and close
the
doors
exceed
the
maximum
acceptable
pull
forces
of
8
kg
[1,
2].
In
addition,
less
than
90%
of
the population
has
the
shoulder
and
elbow
strength
required
to
safety
open
and
close
the
doors
at
the
current
forces [3].
When
forces
exceed
strength
capabilities,
it
hinders
an
individual’s
ability
to
perform
the
task,
and
the
higher the
portion
of
the
population
not
capable
of
performing
a
task,
the
greater
the
risk
of
overexertion
injury.
The forces
of
open
and
close
the
doors
results
in
increased
risk
of
injury
and
is
cause
concern.
Countermeasures
It
is
recommended
to
investigate
countermeasures
to
decrease
the
force
to
open
and
close
the
doors
and
to improve
the
vertical
height
of
the
handles.
Ensuring
maintenance
of
the
doors
is
critical.
A
recommended countermeasure
is
to
install
a
new
lighter
door.
An
optimal
recommendation
is
to
install
bifold
doors
or
automatic roll-up
doors
which
would
eliminate
the
awkward
postures
and
improve
the
force.
References
- Eastman Kodak Company. (2004) Kodak’s Ergonomic Design for People at Work (2nd Edition) (S. N. Chengalur, S. H. Rodgers, and T. E. Bernard, Eds.) John Wiley and Sons, Inc., New Jersey.
- Mital, A., Nicholson, A.S. and Ayoub, M.M., A Guide to Manual Material Handling, 2nd Ed. Taylor and Francis Ltd., 1997.
- 3D Static Strength Prediction Program (3DSSPP) 6.0.1, University of Michigan.