32 NEWEQUIPMENT.COM I DECEMBER2019
While it was once common for warehouse man- agers to purchase standard storage racks that could be “quick-shipped” from rack manufacturers’ stocked inventory, this occurs less often as racking
becomes more specialized and regulations become stricter.
Today, storage rack systems are generally considered a
building-like element, so are often subject to a variety of
federal, state, and local regulations. These ordinances are
continuing to evolve—perhaps none more so than seismic
standards—and can become a pitfall for warehouse managers unfamiliar with them.
1. Limit the use of quick-ship pallet racks to non-flam-mable, non-hazardous product stored inside buildings
in low-risk seismic regions.
Usually, with quick-ship racks, there is a maximum pallet
load limit that the racking can handle and a maximum bay
load limit that the racking and the existing warehouse floor
can handle. There is also usually a 6-to- 1 height-to-depth ratio
placed on the racking. Any rack outside these parameters
typically requires a qualified design professional’s review.
Even when the quick-ship rack is appropriate for a warehouse, there may be a need for expert input if there are
special circumstances—for example, if rack installation
occurs on a sloping floor.
While purchasing quick-ship racking is convenient for many
standard applications, many larger, more complex warehouse
applications today require expert input from a design professional. Trouble often occurs when someone decides that it
is quicker and cheaper to buy quick-ship racking when the
application really calls for an engineered system.
2. Stay compliant with seismic and
Because storage racks are considered building-like structures according to the International Building Code and are
represented as such in the Rack Manufacturer’s Institute
(RMI) Standard, racks need to be designed to the local
seismic requirements just like a building.
Since the RMI is the recognized U.S. specification for the
design, testing, and utilization of industrial steel storage
racks, responsible warehouse managers will want their
racks to meet this recognized standard for seismic design.
RMI created the R-Mark Certification Program as a way
for storage rack users to clearly identify those rack manufacturers whose components and design are in accordance
with the RMI Specifications. Steel King is one of a select
number of rack manufacturers that holds an active R-Mark
License, and is a licensed fabricator in Los Angeles County,
which has some of the strictest seismic codes in the nation.
While all U.S. states have some potential for earthquakes, 42 of the 50 states have a reasonable chance
of experiencing damaging ground shaking from an earthquake in 50 years, which is generally considered the
lifetime of a building.
One reason for warehouse managers to seek a design
professional’s input is the fact that seismic zone designa-
tions are changing. The United States Geological Survey
(USGS) uses ground accelera-
tion values, referred to as Seis-
mic Design Categories (SDC)
from A to F.
With seismic requirements
increasing in many parts of
the country and with a better
understanding of structural performance during an earthquake
event, these standards will continue to evolve, placing more demand on the rack design.
Seismic separation is another
requirement for racks placed
within an existing warehouse.
This means the rack needs to
be a certain distance away from
the building columns so they
will not collide during an earthquake. In high seismic regions,
special inspection is typically required. An independent
inspector will watch the installation and verify proper bolt
tightening, especially the anchor bolt, along with checking
for rack damage and missing or poor welds.
Outdoor racking as well as rack-supported structures must
also be designed to account for wind, rain, and snow loads.
In hurricane prone regions, for example, outdoor rack and
rack-supported structures must be designed to withstand
the force of high-speed winds in addition to standard product
and dead loads.
When heavy snowfall is prevalent, the outdoor rack and
rack-supported structures must accommodate the accumulated weight of both snow and snow drifts, which occur when
wind pushes snow up against taller structures or towers.
In all such unusual environmental conditions, of course,
it is essential to consult with a professional about incorporating necessary safety factors into the rack design.
3. Engineered systems including pick modules and
AS/RS structures have additional considerations.
An engineered system is any non-standard storage rack
that requires special design considerations. This can include a variety of rack types and safety equipment that is
semi-customized or custom-designed specifically to the
In terms of safety, racking of course must be designed
for any unusual stresses, loads, or functions placed upon
it. It must also meet applicable fire codes and insurance
requirements. For instance, racking loaded with flammable
products would require certain accommodations to assure
adequate fire detection, containment, and suppression.
Some of the most highly engineered systems involve
pick modules, elevated platforms, and work platforms. In
such engineered systems, several key factors must also be
addressed to ensure safety, compliance, and permitting.
To comply with the fire code, you need to address the
means-of-egress (the path to exit a building), travel dis-
tance, and head clearance/exit width. This is based on
the number of people who must evacuate the racking system.
In order to provide safe access and fall protection, the
placement of suitable stairs, ladders and guarding should
also be implemented throughout the engineered system.
Because dropping off pallets or equipment at elevated
levels may be needed as well in such engineered systems,
providing for safe drop zones, through an opening in the side
railing to allow easy receipt, should be properly planned, too.
Ensuring that the engineered system functions as de-
signed and that the employees working on an engineered
rack structure feel comfortable is another consideration.
Generally, this is referred to as serviceability. The term refers
to how certain structural elements like elevated walkways
must provide the desired support and stiffness for walking
or cart use without unacceptable flex (bounce) or sway.
While such engineered systems require substantial input
from a design professional, AS/RS structures—which can
be over 100 ft tall and bear loads greater than 100,000 lb.
per storage bay—require even more planning and integration.
In today’s warehouse environment, AS/RS systems are
increasingly popular in big box store distribution centers and
large freezer companies for their ability to provide very high
volume, high turnaround storage with minimal labor.
With AS/RS systems, there is a lot more interfacing between
the equipment and the racking. Because these systems use
automated cranes and usually map each location on a coor-
dinate plane via computer, the tolerances are a lot tighter.
Since the machines stop at precise locations, each open-
ing must be at the exact location. So, the racking must be
very stiff, and the rack must be straight and plumb.
While following these 3 tips can help warehouses stay
safe and compliant, as regulations change and requirements
become more complex, it is always a good idea to partner
with an expert whenever there is a question or potential
complication. This can help to ensure durable, cost effective,
compliant storage rack.
Despite greater warehouse complexity and evolving regulations, understanding a few key distinctions about
racking will help warehouse managers to keep their facilities cost effectively safe, compliant, and productive.
FOR KEEPING WAREHOUSE STORAGE
RACKS SAFE AND COMPLIANT