Elevated thinking
October 1st 2011 Racking specialist Redirack offers advice to warehouse managers on high bay racking
The attraction of high bay racking is clear.When
considering building costs, the higher you can go, the
cheaper the costs per pallet per square metre.When a
pallet location is required to be accessible for picking at all levels
in an environment where space utilisation is important, high bay
racking comes into its own.
There are many factors to consider at the outset of any project,
a summary of which can be found here.
1Building High bay racking by its nature is determined by the
building.We observe space and density becoming more
important to the 3PL environment. High bay should preferably
be installed in new warehousing developments with good floors:
Category 2 minimum, with Category 1 required in the aisles for
VNA.
2Aisles and clearances A consideration should be made of
aisle dimensions, and transfer aisle requirements. In addition,
we recommend that within narrow aisle schemes, the clearance
between the widest part of the laden truck and the face of the
racked load is 100mm for mechanically guided trucks. If you are
using wire guided trucks, this dimension should be increased to
150mm. These clearances may have to be increased if your floor is
not to standard or you are going more than 12 metres high.
3Tolerances As tighter aisles and higher beam and pick
heights become more important to warehousing, tolerances
become key, with floor spec and vertical alignment for racking
critical to the performance of both the truck and racking. In
addition, as with all systems the pallet and load sizes need to be
determined to prepare a detailed rack layout.
4VNA This is currently the route of choice for most operations
requiring a speedy operation with a high density of pallet
locations.Man up VNA has many benefits, primarily the ability to
pick from the storage system at many levels. There are many
guidance avenues to take regards VNA with racking. The majority
of installations currently opt for wire guidance as a cost effective
solution which offers free access to all ground floor positions.
Roller guides are being used mainly with man-down
equipment and guidance for man-up. Angle guide rail provides
another option and offers a degree of protection to the rack but
does impose some restrictions on access and may require
additional clearances.
5Picking To maximise speed of operation, the VNA trucks will
collect pallets from P&D (pick and drop) stations at the ends
of the racks; these will normally be fed by reach or
counterbalance trucks and the P&Ds will usually incorporate
guides to ensure the pallet is always picked up correctly by the
VNA truck. A variety of P&D methods are available. Consider if
there is a requirement for case or item picking.
6Obstacles Consider sprinklers, these can impact on
clearances and the installation method. Also consider the
often overlooked power source: The provision of charging
facilities or a battery management system can influence the
layout and compromise pallet positions. Busbars within the rack
will offer consistent power supply but will impact on rack design.
Also remember Warehouse Management Systems (WMS) may
influence pallet placement and control.
7Damage No matter how well your storage system is designed
and your drivers trained, collisions between forklift trucks,
their loads and storage racks are inevitable.We encourage our
customers to regularly inspect their racks for damage, have a
formal rack inspection carried out by an expert at least once a
year and to motivate their forklift drivers to report damage.
8Built-in protection Racking has moved forward in recent
years with new product and protection methods being
incorporated into the installed product. Frame protection and
frames with sacrificial legs are more and more common as
maintenance becomes the new focus of the long term life of a
racking solution.
9Protecting people To secure areas you may need to install
mesh protection, so this is a detail that should be considered
at the design stage.
Further detailed information on VNA and other rack
applications can be found at
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