Keeping Runways Up When the Snow Comes Down!

Contributed by United Rotary Brush
Photo Courtesy of Denver International Airport
Airports invest significant time
and resources in snow removal
equipment and operations. Proper
brush selection helps increase the
return on that investment.
Keeping Runways Up When
the Snow Comes Down!
Over the past 60 years, the average annual snowfall at Washington
Dulles International Airport in Washington, DC has been 22.2”
according to NCDC/NCOA.
This past February, Washington Dulles received nearly a year’s worth
of snow in a single day; part of a record-breaking 75-plus-inch winter
that underscores the importance of a well-planned snow removal
program.
When a major blizzard shut down Denver International Airport
in late 2006, it provoked a complete overhaul of the airport’s snow
removal efforts, according to Ron Morin, Director of Field Maintenance.
“The following season we asked several manufacturers of
multifunctional snow removal equipment to participate in a field test,”
Morin relays. “We formed an evaluation team that included our airline
partners as well as our Finance and Operations divisions.”
Denver’s new program was fully integrated this past season.
“Our philosophy is that we want a broomed surface … we want the
highest coefficient of friction possible,” Morin explains.
“Brooms are the reason we went with multifunctional equipment,”
he elaborates. “The plow takes away the heavy snow; the broom brings
Contributed by United Rotary Brush
refine the testing and qualification. URB also works with
numerous equipment manufacturers and other service
providers to improve the performance of airport snow
removal brooms.
The Science of Snow Removal
One such company has been Tradewind Scientific,
a leading provider of friction measurement, airfield
condition reporting and environmental monitoring
solutions.
Photo courtesy of Washington Dulles International Airport
Airports must be ready to clear runways of snow, ice and
slush any time, day or night.
it down to the concrete surface. Without the broom,
you’re not going to get down to the surface.”
Other operators agree.
“The broom is our #1 piece of snow removal
equipment,” says Shannon Oldfield, Director
of Maintenance, Cincinnati/Northern Kentucky
International Airport. “It’s the most utilized piece of
equipment we have. It gives us the feeling we’ve given
the best performance we can.”
Brooms first began to
be used for airport
snow removal in
Canada in the mid1950s. Convinced
sweeping could
be a more
efficient and
economical
method
than plowing,
Transport Canada
issued a request for
development and testing
proposals.
United Rotary Brush was one of the early—and only
successful—respondents to this RFP, according to Harry
Vegter, the company’s Director of Engineering.
In the years since, the company has worked with
Canada’s Department of National Defense (DND) to
“What people misunderstand about friction is that
it’s all about the very top of the surface,” explains Len
Taylor, President and CEO of Tradewind Scientific.
“It doesn’t matter how good the grooving is … how
good the pavement is … how good the clearing is … it’s
what’s on the surface that counts. That last skiff of snow
or slush is where it’s won or lost in the friction world.”
Taylor has been involved with runway friction testing
for more than 30 years, and has seen the practice evolve
from subjective evaluations by snow removal crews to
its current, highly scientific process.
Transport Canada also helped push many of these
developments forward through its program to design,
develop and distribute an electronic decelerometer
specifically for runway testing.
“Equipment has advanced quite a bit,” Taylor
concedes, “from mechanical to electromechanical to
electronic data collection.”
The decelerometer essentially gives a spot check
on the runway, according to Taylor. Continuous Friction
Measuring Equipment—like the Sarsys Friction Tester
and the Findlay-Irvine GripTester Tradewind Scientific
represents—give far more accurate and representative
readings.
”I’ve had situations where pollen changed the
friction,” Taylor emphasizes. “It’s what’s between the
airplane and the ground that matters. That’s why
brooming is an essential finish. It’s a vital last step.”
However, advances in equipment technology are
not limited to friction testing. Sweeper manufacturers
have steadily increased broom horsepower and rpm in
order to increase the amount of material to be moved
and the distance it can be thrown.
“It’s great to have a lot of torque; it helps keep speed
up when you have a lot of load,” explains Mark Philpott,
Contributed by United Rotary Brush
Equipment Programs Coordinator at Washington Dulles
International Airport. “But you also have to have material
that will hold up. The harder you work them, the more
you want to ensure you have a good quality brush to
tolerate the urgency of the task.”
“The structural integrity of the individual wafer has
become a focus point,” United Rotary Brush’s Vegter
acknowledges. He identifies filament material, anchoring
technique and wafer balance as key manufacturing
issues to address integrity.
“We worked very closely with our wire suppliers
to get the right combination of tensile strength and
carbon content to create the right wire,” Vegter recalls.
“It’s similar with our poly bristles. We use a proprietary
chemical composition that’s blended to offer greater
resistance to breakage in frigid temperatures and, at the
same time, the flexibility needed to withstand higher
rpm operations.”
Learning from Experience
Of course, not all advances originate in the laboratory.
United Rotary Brush service technicians also work
with airport operators to identify and promote usage
practices that enhance broom effectiveness and
longevity. Vegter grouped field issues affecting the
life of the broom into three broad categories: surface
conditions, down pressure and operator experience.
Airport operators recognize the importance of these
issues and are eager to learn—and share—from each
others’ experiences.
“You can prepare all you want but Mother Nature
will throw a monkey wrench at you,” admits Paul
Atwal, Technical Inspector, Airfield at Toronto’s Pearson
International Airport. “It’s a year-round process. You
have to constantly review your plan, tweak it to make it
better, learn from your mistakes and have the flexibility
to change when you need to.”
“That double blizzard was my first year as manager,”
chuckles Gary Gottner, Stockroom Manager at Denver
International Airport. “You get educated pretty quick.”
Others lessons are developed over time, through trial
and error. Denver’s method of loading a broom is one
example.
“We use a specific combination of wire bristles (w),
poly bristles (p) and spacers (s) that seem to work best
Photo Courtesy of Cincinnati/Northern Kentucky International Airport.
The tips of the broom provide both the cutting and “flicking”
actions needed to remove snow, slush and ice.
for our conditions: 2p/s/2w/s/1p/s/2w/s/1p/s/2w/s/2p,”
Gottner shares. “The wire gives more of a scrubbing
action and the poly more of a sweeping action.”
Brush manufacturers recommend wire bristles
for icy or frozen, packed snow conditions; when
conditions are less severe—dry, powdery snow, for
example—poly bristles provide effective cleaning
without causing undue stress to the runway surface.
Denver expects to get 90 to 110 hours of usage
from each set of brooms. Prior to 2006 and the
subsequent changes to snow removal operations, they
averaged 30 to 45 minutes to clear a runway. This past
year, the average was 13 minutes.
The goal at Cincinnati/Northern Kentucky
International Airport is 120 hours of usage, according
to Oldfield, although he admits it varies from operator
to operator. The facility uses a 50/50 poly/wire combo
on its four runways, and periodically does side-by-side
tests to compare performance.
“We’ll use bristles from different manufacturers
on the same core,” Oldfield explains. “You can check
at 20 hours, 40 hours, 50 hours, and immediately tell
Contributed by United Rotary Brush
the difference, based on the length of the bristle and the
tendency of the ends to fray. If you look at the end of the
bristle, you’ll see some that break apart and mushroom
at the end. A good bristle will just get shorter as it wears
down.”
Oldfield’s snow removal crew averages from 30 to
40 during the winter, but can balloon to twice that size
during a moderate to large event.
Washington Dulles also uses a 50/50 combination
of poly and wire wafers to clear its four runways. Crews
normally work six-hour shifts, but in a prolonged event
(two days or more) they stretch to eight hours to give the
equipment more time on the field and the off-shift more
time to rest.
Winter temperatures hover around freezing and
so the airport deals primarily with wet, heavy snow.
While most airports aim for 100+ hours of broom usage,
Philpott concedes that isn’t always possible.
“When the snow gets heavier, you have to run a
heavier pattern,” he acknowledges. “The heavier the
pattern, the heavier load you put on a broom. I try to
encourage my people to do a 4” pattern; some operators
run a little heavier.”
Philpott relies on a core group of long-term,
experienced operators to train newer users. He
also advocates similar shared learning as a part of
procurement, insisting on speaking with other like-sized
customers about their experience with the product …
and the company providing it.
“We ask about everything, from how well the bristles
last to how well the company fills a rush order to how
accurate the invoicing is,” he explains.
Pearson International Airport in Toronto uses only
wire brooms because the wet, heavy snow tends to get
compacted and is more difficult to remove. Cassette
style sweepers are used to clear the runways; wafer
brooms the taxiways and aprons.
“There are benefits to both formats,” Atwal allows.
“The cassettes are quicker and much easier to change.
But I feel the wafers do a better job of snow removal.”
Atwal expects to get 100-plus hours usage from
all brooms. The Vammas cassette units have a running
clock to verify that performance. But it’s hard to compare
which actually lasts longer.
Photo Courtesy of Cincinnati/Northern Kentucky International Airport
Recent winters have reinforced the need for airport preparedness
as major winter storms pummeled a number of high traffic
facilities.
“The cassette goes down and is on the ground the
full length of the runway; wafers are used on shorter
surfaces and tend to go up and down more” he explains.
“In addition, surfaces are different: aprons and taxiways
are a mix of concrete and asphalt, not retextured like the
runways are.”
An Investment Worth Considering
Airports invest significant time and resources in snow
removal equipment and operations. They have to; it truly is
a matter of life and death.
Many other organizations—specialists like United
Rotary Brush and Tradewind Scientific—are also
working to advance the industry. And to make sure
airport maintenance crews have the equipment—and
information—they need to keep air travel safe during
winter snowfalls.
While sweeper brushes may appear to be a minor
portion of the overall investment, their importance to the
final results far outweighs that relative cost. That makes
brush performance even more critical … which, according
to Harry Vegter, is why United Rotary Brush will continue
to commit such significant investments in airport broom
research and development. n