Vehicle Loads— How Secure is Secure Enough?

Vehicle Loads—
How Secure is Secure Enough?
CFR 393.102 specifies minimum performance criteria for cargo-securement devices and systems.
By Brad F. Kuvin
Contributing Editor
Cleveland, OH
early three years ago, the
Department of Transportation
(DOT) and its agency the
Federal Motor Carrier Safety
Administration (FMCSA) began enforcing new cargo-securement rules, introduced in 49 CFR (Code of Federal
Regulations) 393.102 (Parts and
N
Trucks and trailers that transport gas cylinders are being targeted by the DOT and
FMCSA in their ongoing efforts to enforce
cargo securement regulations introduced
in CFR 393.102.
“ . . . they are looking more closely
than ever before at
the compressed-gas
delivery vehicles on
the road.”
Accessories Necessary for Safe
Operation; Equivalent Means of
Securement). With the regulation, the
FMCSA hoped to address a long-standing debate among transporters of hazardous materials. That is: When securing cargo to vehicles, how secure is
secure enough?
The ramped-up enforcement policies
of the FMCSA, charged with improving
truck and bus safety on our nation’s
highways, follows a trend in our industry carried forth not only by the DOT
but by other government agencies.
Take, for example, the FDA and its
tightening grip on the procedures used
to fill medical-oxygen cylinders. When
the FDA first began to ask for the separation of medical-gas filling and industrial-gas filling, many in the compressed-gas industry scoffed. “The
source gas is the same for both,” they
said. But now, we see more and more
new fill facilities ordering separate bulk
tanks for medical and industrial oxygen,
and perhaps one day soon we’ll see two
different tankers delivering two types of
oxygen.
The point here: When was the last
time we saw our government ease up on
regulations? Never, right? And so, now
those companies that must take responsibility for safely yet efficiently transporting compressed-gas containers face
a new challenge from the DOT and
FMCSA, whose stated goal is a reduction in the number of serious transportation incidents of 20 percent by 2010
compared to 2000.
Rollover Reality Check
Mark Walker, general manager of the
industrial gas group at of Matheson TriGas, out of the firm’s Irving, Texas
industrial-gas group headquarters,
addressed the FMCSA and 49 CFR
393.102 by stressing, “Several states,
particularly southern states such as
Texas and Florida, are ramping up DOT
compliance activity related to cylinder
securement and the new regulation. We
see that as their enforcement officials
are becoming more trained on the
requirements of 393.102, they are looking more closely than ever before at the
compressed-gas delivery vehicles on the
road.”
Praxair’s Dave Sonnemann, manager
of transport regulations and fleet safety
in the corporate safety department in
Danbury, Conn., concurs, noting an
increase in enforcement activity, rooted
in the south, which began 6 months ago.
“There are a lot of large ports in the
south, and when you’re shipping internationally, one of the things you do to
minimize handling is palletize,” says
Sonnemann.
CFR 393.102 specifies minimum
performance criteria for cargo-securement devices and systems. Basically, it
requires that cargo be secured so that it
can withstand these forces: 0.8-g deceleration in the forward direction, and 0.5g acceleration in the rearward and lateral directions. The regulation also
requires that if the cargo is not fully
contained within the vehicle structure,
the securement system used must provide a downward force on the cargo of
at least 20 percent of the cargo weight.
“What we’ve seen in our industry in the
past is that some pallet-securement systems will actually separate from the
vehicle during an accident on the road,”
says Walker, “particularly in rollover
events. The pallet system we use at
Matheson Tri-Gas, the Weldcoa
As shown in the unfortunate accident above in which a trailer was rolled onto it’s side,
pallets that are secured mechanically to trucks and trailers, rather than relying on gravity,
can remain secure in the event of an accident.
Instaload palletized process (with
Weldcoa’s Sur-Loc pallets) actually
locks the front of the pallet down to the
vehicle with a locking bar that interlocks
to the bed of the vehicle. Then, the back
of the pallet locks down with two pins
secured to the outside rail.
In every single accident we’ve had with
our vehicles, including rollovers, the
load has remained in tact. This was best
demonstrated a few years ago in New
Mexico, where one of our vehicles was
hit on the front corner by another trac-
tor-trailer. This was a fairly significant
impact, and the load stayed in tact.”
While Matheson has been using the
Weldcoa system for some 15 years, and
has probably 70 trucks and hundreds of
its pallets, estimates Walker, Walker was
happy to hear that Weldcoa has recently
had its system tested to compliance with
49 CFR 393.102.
“The concept of ‘secure’ was always
somewhat vague before,” says Walker.
“Now that we know the system we use
meets the DOT requirements, any wor-
The transportation system used by Matheson is the Weldcoa Instaload System with Sur-Loc
pallets (shown left and above). The pallets lock to a center bar that is part of the frame of
the truck/trailer. The railed side of the pallet automatically and mechanically locks on both
sides to the truck frame. Recent testing of this system proved compliance with regulations
established in CFR 393.102.
Results of the Weldcoa Pallet System Compliance Testing
“Now that we know
the system we use
meets the DOT
requirements, any
worries we may
have had are gone.”
Forward deceleration
Required, 0.8 g Analysis results, 1.2 g cyclic and 1.4 g one-time acceleration
Rearward acceleration
Required, 0.5 g Analysis results, 1.9 g cyclic and 2.2 g one-time acceleration
Lateral acceleration-inward
Required, 0.5 g Analysis results, 1.2 g cyclic and 1.4 g one-time acceleration
ries we might have had are gone.”
Praxair, too, has for several years standardized on the Weldcoa pallet system.
“However, as a result of the new regulation,” shares Sonnemann, “we have had
to go back and look at the vehicle fleets
we have acquired in recent years, to
make sure that they meet the requirements of the regulation.
Lateral acceleration-outward
Required, 0.5 g Analysis results, 1.2 g cyclic and 1.4 g one-time acceleration
The Proof is in the Stress
Analysis
To prove compliance to CFR
393.102, Weldcoa recently asked a
licensed professional engineer to perform a stress analysis on its Instaload
pallet system. The engineer analyzed
three- and four-rail pallets installed on a
Weldcoa truck or trailer body, with 21
168-lb. DOT cylinders nested and bound
with two straps. The engineer looked at
both one-time and cyclic (2 million
cycles) acceleration, in four acceleration
vectors: forward, rearward, inboard (lateral acceleration due to an inside turn)
and outboard (acceleration due to an
outside turn).
How did the pallet system hold up?
Compared to the deceleration and acceleration requirements, the system was
found capable of withstanding accelerations from 1.75 to 4.4 times the stated
limits.
As far as the 20-percent downwardforce requirement based on cargo
weight, Weldcoa chose to test to 49
CFR 177.840, which specifically
addresses securement of DOT cylinders
carrying compressed gases. This regulation calls for the securement of cylinders to prevent their overturning, either
by secure lashing in an upright position,
loading into racks securely attached to
the vehicle, packaging in boxes or crates
or loading horizontally. When Instaload
pallets, loaded with 21 cylinders, were
inverted, no cylinders fell out of the
restraints. Weldcoa repeated the test
three times, proving that the restraining
force exceeded 100 percent of the cylinder weight, and at the same time meeting the 20-percent weight requirement.
The last thing the industry needs, particularly in a vehicle rollover, say both
Walker and Sonnemann, is cylinders
scattered all over the highway. By complying with 49 CFR 393.102, both say
that when they send their trucks out,
they’re confident that should an accident
occur, the loads will remain in tact with
the vehicle.
When cylinders were double strapped to
the pallet and inverted in testing all of
the cylinders remained secured by the
restraints.