Case Study
The following case study shows how this
guidance can be applied to the system of work for picking objects from
a walk-in bay or from the floor to a pallet.
MANUAL ORDER PICKING FROM PALLET RACKING
TO A PALLET
Activity Description
Objects are manually picked from a storage
pallet in pallet racking. The racking design may be such that the storage
pallet is in a walk-in level, or it may be stored in the first, second
or third level of the racking. Objects on pallets at the second or third
level may be out of the person's reach and so the person needs to be
raised or a mechanical aid must be used to reach these objects.
Picked objects are placed onto a picking
pallet and stacked until the pallet is 2m high. The picking pallet is
moved from one location to another location using a hand pallet truck,
an electric pallet mover or a forklift. When the order is finished or
when the picking pallet is full, it is stretch-wrapped and moved to
Despatch. At some stage, the picking pallet may need to be partially
stretch wrapped to stabilise the load and allow further objects to be
stacked on top.
The objects picked in this scenario include
boxes, bags, buckets, small drums and other easily handled objects weighing
up to 25kg and long, bulky, unstable or awkward objects weighing up
to 25kg.
Note: The following objects are out of
scope for this scenario:
Objects longer than a standard pallet;
and
Objects above 25kg as the workplace requires
these are handed by two persons.
Risk Assessment
A risk assessment conducted under the Manual
Handling Regulations established that there was risk due to repetitive
application of force, sustained movements, repetitive awkward postures,
high force and environmental conditions in cold storage facilities only.
Reference to the Order Picking Weights diagram indicated that some picked
objects exceeded the weights in the diagram.
| Source of Risk |
Details |
| Workplace layout |
Moving order pallet
over long distances involves sustained forces. (see solution
a)
Storing objects in picking locations
without considering how stackable they are on the order pallet
may require that the employees criss-cross the warehouse to
build their pallet or they will need to repack the order pallet
several times while selecting an order. (see solution b)
Locating a picking pallet on a
high level may require that employee use other equipment to
raise them to pick objects from that location. (see solutions
c, e & f)
Aisle width determines what equipment
can be used in aisles. (see solutions g & h ) |
| Racking design |
Height of the first
beam determines whether persons have to stoop to enter the first
bay. (see solution d)
Double bay racking restricts access
to the rear of pallets. (see solution i)
Double deep racking restricts access
to the rear of the pallets. (see solution j)
Racking design and specifications
will determine whether order picking forklift or other such
equipment can be used with it. (see solution k) |
| Tools & Equipment |
Design issues of
the picking stick such as weight, length, balance, method of
selecting objects and how to store the object will affect how
far someone has to reach to get an object, the static load on
the hands, arms and shoulders, and how readily it will be used.
(see solution l)
Using a hand pallet mover over
long distances will require the sustained application of force.
(see solution a)
Using a platform ladder to pick
objects will require repetitive climbing and descending of stairs
while holding a load (see solutions e & f)
Hand stretch wrapping requires
repetitive awkward postures and sustained forces (see solution
bb) |
| System of Work
- Team handling |
Not enough competent
persons available to assist with handling (see solutions e,
h, m & n) |
| System of Work
- Work rates |
High pick rates
will increase the amount of fast and jerky forces and repetitive
awkward postures (see solutions r) |
| System of Work
- Work flow |
Delivery and loading
schedules which impose a strict time limit on manual picking
or replenishing will increase the handling frequency and increase
the amount of fast and jerky movements (see solution s). |
| System of Work
- Job rotation |
Work/rest cycles
do not allow persons to recover sufficiently from the work undertaken
(see solution q). |
| System of Work
- Shift length |
Amount of work
done over the shift leads to physical exhaustion. (see solution
r) |
| Objects handled |
Bag/sack/carton
design
- Objects not stored on pallets
prevents their picking or replenishing by mechanical aids
(see solutions a & u).
- Lack of handles or poor
placement of handles will require higher force to handle
object (see solution v).
- Weight and size of objects
handled will determine postures and forces to be used. The
order picking weights diagram demonstrates weights that
could be handled from various locations in racking or pallets
(see solution w).
- Type of material stored
in bags affects the ease of handling e.g. flour and plastic
beads form a semi-solid object that is difficult to handle
due to its instability while other material such as cement,
sand and salts can be firmer and stable when handled (see
solution x).
- Objects with unstable contents
or where the centre of gravity is not central can be difficult
to handle. Lifting or carrying the heavier side of an object
away from the body poses a risk as does handling an unstable
object (see solution x & m).
Mixed loads
Picking of small objects on top
of heavy large objects on a picking pallet where access to the
top layer cannot be gained by standing on objects stored on
the floor requires high force to be exerted in awkward postures
to reach these top objects (see solution y). |
| Environmental conditions |
Lack of instruction
in how to minimise risk by using the appropriate equipment,
procedures and techniques during this task (see solution m).
If a bag or sack is lifted flat,
the employee cannot get the load close to the body, which increases
the risk. If a bag or sack is picked up and carried on end,
then the hands, arms and shoulders predominantly support the
weight. The risk of injury increases if loads are handled with
smaller muscle groups (see solution m).
Handling objects over floor surfaces
that are uneven, damaged, sloped and sometimes wet and slippery
will expose persons to sudden and unexpected forces (see solution
o).
Picking objects in areas of poor
lighting may mean that more awkward postures are adopted to
read the label (see solution z)
Picking objects in hot temperatures
or close to radiating sources of heat such as the roof, may
cause sweating and will expose persons to sudden and unexpected
forces (see solution aa) |
Solutions
It is usual to implement a number of these
risk control options together to reduce the risk as far as is practicable:
a. Use powered mobile plant to move
picking pallet
b. Group all stackable objects so that
the base of the picking pallet can be selected first.
c. Only use first level of racking
for picking.
d. Height of the first beam to be 1.85m
or more above the floor
e. Order picking forklift used to pick
from higher levels of racking
f. Purpose-built mobile work platform
or similar device used to raise employee when picking a few objects
from higher levels of racking
g. Use reach forklifts in narrow aisles
to mechanically load pallets.
h. Use order picking forklifts in very
narrow aisles to pick objects.
i. Use single bay racking where good
access is required to both the front and the rear of the pallet.
j. Use double deep racking for storage
pallets only.
k. Ensure racking specifications such
as height, angle from perpendicular, floor gradient and level are
appropriate for use with order picking forklift or other such equipment.
l. Use a lightweight picking stick
that can reach to the rear of a pallet to move objects to the front
for picking.
m. Provide instruction, training and
supervision on techniques for safe handling of objects to ensure
competency of persons required to pick or replenish objects; e.g.
how to use equipment and how to select appropriate techniques with
lowest risk for the conditions encountered. A more appropriate procedure
than to lift objects and carry objects is to pull and slide objects
onto a pallet within the Best Working Zone.
n. Provide assistance from other persons
as required.
o. Fix slippery and uneven surfaces.
p. Implement a regular maintenance
program on mechanical aids, pallets movers and racking.
q. Ensure adequate work/rest cycles
to allow persons to recover from the physical work undertaken in
manual picking or replenishing.
r. Ensure that the work rate for manual
picking or replenishing is matched to the shift length. Any increase
in shift length should result in a decrease in the number of objects
handled per hour per person.
s. Schedule the packing and unpacking
of containers when there are adequate numbers of persons and time
to do the job at a safe pace.
t. Ensure manual picking and replenishing
work rates are determined in consultation and take into account
the total amount of work required to be conducted over a shift.
u. Use a mechanical system such as
layer picker, vacuum system, robot and the like to pick objects.
v. Ensure objects are stored in cartons
with handles.
w. Allocate objects to picking locations
in line with the Best Working Zone weight tables.
x. Allocate objects to picking locations
after considering their ease of handling.
y. Limit the total height of the picking
pallet to 1.2 to 1.6m.
z. Ensure appropriate lighting for
the tasks required.
aa. Ensure picking near high radiant
heat loads, such close to the roof, is conducted during periods
of the day where the heat load is minimised or provide cooling.
ab. Use an automated stretch-wrapping
machine.
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