Salt Lake City Int'l Diversifies Deicing Options & Changes Purchasing Procedures

Ken Wysocky
Published in: 

When environmental concerns prompted the FAA to ban ammonium nitrate (also known as urea) for pavement deicing, airports throughout the country had to find a replacement for the once-standard chemical. Salt Lake City International Airport (SLC) seems no worse for wear. Its crews now use three different deicing agents, and a revamped purchasing process helps the airport secure a competitive price for each one. 

The ban, which occurred in June 2012, prompted SLC to test three more eco-friendly agents: sodium acetate, sodium formate and a blend of both. In the end, the airport opted to use all three FAA-approved options, each for different weather conditions.

"We found they all worked well; each one has characteristics we like," explains Medardo Gomez, superintendent of airport maintenance operations. "Some work better in warmer temperatures and some work better in colder temperatures. Our ultimate goal was not to limit our options, especially since safety is so important."

Project: New Deicing Strategies
Location: Salt Lake City (UT) Int'l Airport
Impetus: 2012 urea ban
Previous Deicing Agent: Ammonium nitrate
Current Deicing Agents: Sodium acetate; sodium formate; blend of both
Suppliers: Cryotech; LNT; NewDeal 
Pavement Maintained: 54 million sq. ft.
2014 Takeoffs & Landings: Nearly 325,000
Airfield Maintenance Personnel: 84 airfield equipment operators; 30 mechanics; 12 electricians
Solid Deicing Product: 500-1,200 tons/winter, depending on severity of weather
Liquid Deicing Product: 150,000 gallons/winter
Sand: 725 tons/winter
Equipment Fleet: 22 pieces 
Trucks: International; Mack
Power Broom Attachments: M-B Companies 
Snow Blowers: Aebi Schmidt; Kodiak America; Oshkosh Airport Products
Plow Attachments: Henke Mfg; Meyer; Wausau Equipment Co. 
Rubber-tire Front Loaders: Kawasaki/KCMA Corp 
Spreader Units: Batts; Meyers; Tyler Ice

Gomez likens the airport's new approach to having a toolbox with three various-sized wrenches instead of just one.

Specifically, SLC crews report that sodium acetate works better on ice than snow. It also stays effective longer than other agents, so it's a better choice for storms that won't seem to quit, Gomez adds. Sodium formate, on the other hand, was found to be more effective under windy conditions because it's flakier texture makes it drift less than sodium acetate pellets. The blend of the two products is dyed blue to make it easier for crews to judge how well the deicer is dispersing. 

Using three agents instead of one could also help protect SLC against market fluctuations and associated product shortages. A few years ago, a Canadian work strike limited the supply of liquid deicing products, Gomez recalls. "If shortages occur now, we still have additional reliable options that we can use," he explains.

To obtain the lowest price, the airport solicits separate bids from suppliers for each deicing agent. Contracts generally run for three years, with modest price escalations built in, says Gomez. 

"Before, we had only one request for proposal for supplying urea," he recalls. "Now, we ask for bids on three separate contracts ... so we can buy three different products at competitive prices. We feel like we get a little better price because there's more competition to supply each product. Continuous competition is good."

Gomez shrugs off the idea that requesting and processing more proposals requires more work. "It's not that difficult," he comments. "It's like ordering navel, red and blood oranges versus ordering just oranges."

Getting the best price possible is critical, Gomez emphasizes. While SLC used to pay about $400 a ton for urea, its newer, "greener" deicing agents cost between $1,600 and $2,200 per ton.

New Facility in the Works

With approximately 54 million square feet of pavement to maintain, keeping enough deicer on hand is a task in itself. Depending on weather conditions, SLC uses anywhere from 500 to 1,200 tons of solid chemicals each winter to clear its four runways and other airfield pavements. It also applies about 150,000 gallons of liquid deicer and 725 tons of sand per winter.  

Given its past and future warehousing needs, the airport is building a new $2 million storage facility specifically designed for deicing agents. Currently, SLC can accommodate 200 single-ton bags of deicing materials. The new 15,840-square-foot building will roughly triple its storage capacity. 

Gomez explains that keeping more deicing materials on hand will increase efficiency and reduce the risk of product shortages during extreme weather or unusual market circumstances. Currently, the maintenance department stores bags of deicing materials in several different outbuildings throughout the airport's 8,040-acre grounds. A single, centralized storage building is expected to improve operational productivity.

"Our goal is to always have enough inventory on hand," Gomez comments. "We certainly don't want to have to close the airport because we ran out of deicer."

Because deicing agents react negatively to moisture and humidity, the double-sealed bags must be stored in a warm, dry location. The new building will be outfitted with a special dehumidification system and include three separate areas: one for storage, another for staging materials for loading, and a third room with a drive-through loading lane for deicing vehicles.

To prepare the product for loading, a forklift raises each 1-ton package, and a worker manually unties the bag. The forklift drops the load from a height of about 6 feet, spreading the dry product onto the floor. Next, a front loader scoops up the product and transfers it to a spreading truck.

"We usually open about 40 bags or so at a time," Gomez says. "When we start to run low, we open up more bags."

In the airport's current loading facility, trucks and other deicing equipment bring slush and water into the staging/loading area - a definite no-no for the moisture-sensitive products. In the new building, the drive-through lane is lower than the staging area to protect the deicers from outside moisture. SLC officials expect the new warehouse to be complete in February 2016. 

Not surprisingly, other airport operators are contacting Gomez to learn more about its new lineup of deicing agents and how it will store them. "We're pretty unique," he acknowledges. "People are starting to notice how we're doing things."

Striving for further improvement, SLC's airfield maintenance department continues to experiment with various deicing agents. "Last winter was only the second year we used these new products, so we're trying new combinations, such as mixing sand with one," says Gomez. "Who knows what else we'll discover? We're excited about that." 


Snow Much to Do

Snow and ice removal is a big deal at Salt Lake City International Airport (SLC). It's also somewhat of a marathon, with winter conditions beginning in late September and running through March. Temperatures usually hover in the low 30s, dropping near zero for some stretches, and Mother Nature delivers an average 57 inches of snow per winter.

"It can get pretty brutal at times, especially from the latter part of December through February," says Medardo Gomez, SLC's superintendent of airport maintenance. "It comes and goes in cycles. Sometimes winter hits early and furiously; and other times it's mild, like last winter. It's been pretty unpredictable during the last several years."

The Great Salt Lake, located just west of the airport, complicates matters by creating lake-effect snow. "We always have to be ready," Gomez comments. "Predictions for a 'trace' of snow can quickly turn into 10 or 12 inches."

To keep traffic moving for eight airlines and their affiliates, SLC pre-treats its runways against ice when storms are predicted. Airfield maintenance crews prepare by applying liquid potassium acetate and FAA-specified sand. Depending on the conditions (temperature, wind speed, moisture content of snow, etc.), workers sometimes also use a deicing agent, which essentially prevents a bond from forming between the pavement surface and any ice and snow on top of it, explains Gomez. Under some conditions, deicers also act as melting agents.

The airport's 22-piece fleet includes trucks, plows, power brooms, snow blowers, front loaders and spreader units (see list on Page 28 for specifics). Crews work 12-hour shifts removing snow and ice from four runways - three for commercial carriers and one for general aviation use - and other airfield pavement. Personnel include 84 equipment operators, 30 mechanics and 12 electricians. 

"If a plow hits a light, for instance, an electrician's truck is right there to repair the damage," Gomez notes. Half of the equipment operators work from noon to midnight; the other half work from midnight to noon. SLC does not provide overnight housing on airport grounds.

Last year, SLC accommodated 21.1 million passengers and handled nearly 325,000 takeoffs and landings, many stemming from its role as a major hub for Delta Air Lines. Throughout the years, the airport has garnered 14 national awards for its snow and ice removal operations.



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