| |
Return to
Previous Page
|
Click here for a Free
Quote
Putting
Together A Rack Job
Scope of Responsibility
Our manufacturer,
Wireway/Husky is a
member of the Rack
Manufacturers Institute
of the USA. Wireway/Husky
fully endorses the
'Specification for the
Design, Testing, and
Utilization of
Industrial Steel Storage
Racks - 2001 Edition'.
Wireway/Husky requires
all of its equipment be
used within the
parameters of the above
stated specification. It
is the responsibility of
any user of this manual
to ensure that their
unique and specific
design application
corresponds in the first
instance to this
Specification, and to
any other local or
national codes and/or
regulations that may be
applicable. The
descriptive guidelines
offered at various
points in this book are
just that, guidelines;
and are only offered as
a starting point for the
general education of any
user of this book. Any
user applying these
guidelines without
reference to both the
Specification and full
knowledge of the
individual application,
national/local codes,
and all applicable
regulations do so at
their own risk.
Step 1. Find out
everything there is to
know about the item you
are handling/storing.
Find out the
three-dimensional size
and weight of every load
and pallet going to any
location. Remember that
the pallet may not be
exactly the same size as
the load, there may be
overhang one way or the
other. Also be careful
to ask about the quality
of the bottom of the
pallets and whether or
not they are capable of
resting on just beams.
If they are broken or
rotted, they might
require wire deck to
safely support them.
Step 2. Find out
everything there is to
know about the area that
the rack is going to be
installed. Start with
the physical dimensions
of the available space.
Next the floor
condition, its load
bearing capacity and any
slope. Find out about
the available clear
headroom and the
presence of any overhead
or other obstructions.
Find out if there are
any access-ways that the
rack must not obstruct.
Column centerlines and
size are also important
for flue space
specification and layout
information.
Step 3. Find out the
method to be used for
storing and retrieving
loads in the rack (often
Fork Truck or Pallet
Jack). Can it carry the
proposed load? What is
its width and right
angle turn dimension?
What is its maximum lift
height? Remember you
must subtract from this
number, usually 6", for
most pallets to be
lifted clear of the
beam. Take note of
anything else that might
impede on its safe
interaction with the
rack.
Step 4. Select the beam.
First decide how many
loads should be on each
beam level. The length
of the beam can be
determined by adding
three inches to either
side of the pallet, (or
load, whichever is
largest), and
multiplying by all the
loads on the beam. For
example, a load/pallet
of 42" width, two to a
beam = 42" +3" +3",
multiply by 2 and this
comes to a 96" beam. The
3" additions are to give
adequate side clearance
for loading and
unloading. The model of
beam should then be
selected from the 'Beam
Selection Chart' below,
making sure that the
loads do not exceed the
maximum capacity. If the
beams are longer than
120" they should be tied
across the middle to
prevent beam spread. If
loose decking is to be
used, any pair of beams
over 90" in length
should be tied across
the middle for the same
reason.
Step 5. At this point
ALWAYS start a sketch of
each individual bay, no
matter how small the
job.
Step 6. Figure out how
many beam levels you
will have in any bay.
Are the first
pallets/loads going to
sit on the floor, or on
a set of beams? To
calculate the number of
levels add together the
pallet and load height
plus 6" for clearance.
Add the face/height of
the beam you just
selected for the overall
total. Fit as many
levels as possible in
the height available
remembering to make sure
the fork truck is able
to lift the pallet off
the top beam with it's
maximum fork height
capabilities. It usually
needs an additional 6-8"
of lift height over the
top beam. Finally make
sure there is enough
clearance for any
sprinkler requirements.
Step 7.
A. Figure out the frame
capacity necessary. Add
up all of the beam loads
acting on the frame,
then work out the
largest pallet opening
on the frame (usually
floor to first beam, but
occasionally beam to
beam above that). Loads
on either side of the
frame up to the center
points of the beams, act
upon the frames. Note
that in the illustration
below there is 15,000
lbs. acting on the
middle frame. Now, using
the capacity chart shown
on page 4, select the
appropriate frame model.
B. Figure out how high
the frame needs to be to
reach the top of the top
beam. In most
applications you should
then add between 6" and
18" (up to the next
standard frame size) to
allow for flexibility in
installation. If the
customer wants the frame
flush with the top of
the top beam, be very
sure to check the load
dimensions again very
carefully and check the
floor for the
possibility of slope in
both the 'cross-aisle'
and 'down-aisle'
directions. C. Figure
out how deep the frame
needs to be. The
dimension of the pallet
determines this. In most
applications an overhang
of 3" on either side of
the pallet is desirable
(if the pallet is 48"
deep the frame should be
42"). If the application
demands that the
pal-lets be flush with
the front and back faces
of the rack bay, cross
supports from beam to
beam MUST be used. The
cross supports may be
crossbars or wire deck.
Step 8. Now put together
your final sketch
showing all the bays
that go together to make
up a row, and count up
all the beams and frames
you need for the
sys-tem.
Step 9. Is your system a
single row? Or will it
be installed
'back-to-back' with
another row of rack? If
it is back-to-back, it
should be tied across
the 'flue space' in the
middle with row spacers.
You should always use a
minimum of two row
spacers no matter the
height. You should also
ensure there is not a
gap greater than 10' in
height between row
spacers, adding a third
or fourth one if
necessary.
Step 10. You must now
check to see whether
your system is stable or
not. First, check the
height com-pared to the
depth for overturning
stability. To do this,
find the height from the
floor to the top of the
very top-most beam. Now,
divide that figure by
either, the depth of the
frame (if this is a
single row); or, the
depth of both frames
plus the row spacers (if
this is a back-to-back
row). Is the answer to
your division sum larger
than 6.0? If so you will
need to call your Husky
representative for
assistance, as the
system is unstable.
Second, check for
rotational stability. Do
you have only a single
beam level between
frames in a bay
anywhere? If so you will
need to call your Husky
representative for
assistance, as this
system also is unstable.
General. General Pallet
rack installations are
structurally engineered
systems that carry heavy
loads. The steps above
give a guideline for the
safe specification of
components for simple
cases where conditions
are perfect. They are
written with regard to
RMI 2001 which is the
guiding industry
specification at time of
publication. If, in the
future, this
specification is revised
or overridden; or, if
you have any doubt or
confusion whatsoever
about any of the steps
above, please contact
your Husky
representative for
assistance.
Final. Please remember
that your system should
be shimmed level and
anchored to the floor
(one anchor per leg).
|
