Pete Oesterling’s a suit-and-tie guy. As associate vice president for Nationwide Insurance, complete with legal staff and an office with a lofty view of Columbus, Ohio, his daily apparel is the requisite uniform. It’s rumored, though, that he favors Harley Davidson t-shirts and has a collection of two-wheeled machines in his garage.

But it’s because of the suit and tie that Oesterling, for years, was reluctant to visit one of his favorite spots for a bite to eat just a block away. All it took was a few minutes at the North Market to be odorously marked for the remainder of the day.

“It didn’t matter how quickly I tried to make the trip into the market,” said Oesterling. “The smell of cooking oils, onions, garlic, and smoke stuck to me like Velcro. That’s OK on a day off, but not on weekdays when I have meetings to attend.”

Like most of the folks in Columbus, Oesterling, now in his 30th year at Nationwide, quickly grew to like the ambience, social atmosphere, and the widely varied experiences anyone can expect at the market.

But the olfactory glue was too great a deterrent. So, like many others at Nationwide — with a population of professionals well above 10,000, most within a quick walk of the market on weekdays — Oesterling avoided trips there during the week.

“As much as I liked going there for a lunchtime treat, the stigma of smelling like the market was too great a penalty,” he said.

Oddly, the smells and rich airborne aromas of fried fish, potatoes, and smoked pork at North Market are an important part of the generously sensual experience that customers — more than a million each year — have come to enjoy. The cultural mix, wide variety of vendor offerings, colors, tastes, and textures commingle with the wafting fragrance of it all.

“That mix of goodness is highly prized here,” said Rick Harrison Wolfe, the market’s executive director. “Though, over the years, our ventilation woes became something we needed to deal with.”

And there’s plentiful goodness in the mix at North Market: At Best of the Wurst, Nick von Ahsen and Kye Pimparatana mix fine brats with Bangkok cuisine; The Fish Guys offer the freshest, line-caught fish in town and hope to grill some of it for patrons soon; and at Holy Smoke BBQ, meats acquire heavenly goodness.

And that’s only a few of the many vendors who ply their trade at the market seven days a week. The eclectic band of merchants, including produce, retail, and food stands surely contributes to the market’s ambiance and defines its uniqueness.

Though, without a doubt, the market’s burgeoning IAQ problems — a byproduct of the enterprise inside — had to be resolved if the nonprofit venue and its 36 vendors were to survive.

Years ago, city managers and market executives knew they had a problem, but they also had to find a way to solve it, and to pay for it. Gradually, a plan emerged.

Wolfe, who joined the market’s executive staff in May 2013, learned about plans to overhaul the building’s ventilation system during his very first day on the job. When he went home that evening, his girlfriend sweetly demanded that he quarantine his work clothes. “She said I smelled like a Vietnamese, Polish, and German stir-fry with fish, peppers, and sourdough clove.”

Undoubtedly, people were aware of the smells of cooking and food preparation, especially at lunch time, and especially during the winter months when doors and windows were closed.

Engineering a Solution

Of course, the science behind the market’s inadequate ventilation was the purview of trade professionals, with a language foreign to the market’s everyday patrons, with terms like particulate parts per million (ppm), IAQ, and cfm.

Enter Stuart Schlotterbeck, a senior mechanical engineer for Columbus-based Dynamix Engineering Ltd., the firm chosen by city managers to engineer a solution to the market’s IAQ problem.

One of the first decisions made by Schlotterbeck was the specification of four, 20-ton Atherion® packaged ventilation rooftop systems manufactured by Modine Mfg. Co., ultimately chosen to be the crown jewels for the market’s IAQ improvement project. Next in line were the central exhaust fan and innovative venting and kitchen hoods. They, too, were soon to become integral components to make the whole, an engineered solution built precisely to meet the current and future needs of the expanding market.

“Of key importance was the need for make-up air,” said Schlotterbeck. Prior to the renovation, air balance tests for the building proved negative as more air was being exhausted from the building than was supplied from outside. “Net pressurization for the building should be positive,” he said. “Tests confirmed the need for more make-up air.”

General Temperature Control

The North Market retrofit project came out for bid about two years before actual work began. Canal Winchester, Ohio-based General Temperature Control (GTC) — armed with Schlotterbeck’s design — submitted the winning proposal during the re-bid process. GTC was chosen to replace the ailing rooftop equipment and to overhaul the ducted ventilation system within the building.

GTC was a natural choice for the job, which began in August 2013 and concluded three months later. The firm’s 35-plus employees include eight sheet metal pros, 12 pipefitters, and six service personnel. The market’s budget for the total project was $1.2 million.

President Bob Billings, who began his career as a refrigeration pipefitter, just like his father, explained as a union shop, GTC simply drew on the local unions (Local 189 of the United Association of Plumbers & Pipefitters, and Local 24 of the International Association of Sheetmetal Workers) for skilled labor support as needed.

According to Billings, GTC’s territory includes the area within a 100-mile radius of Columbus. The firm is exclusively focused on industrial and commercial HVAC system work.

“We do a wide variety of work, including renovations and service,” said Billings. “A large percentage of our commercial work is done for schools and universities, with a lot of work for Ohio State University, projects for the city of Columbus, and many state of Ohio projects, as well.”

Billings chose Mike House, project manager, to direct the North Market’s ventilation retrofit. House, who began his career at GTC 15 years ago as a sheet metal pre-apprentice, said the North Market project involved a lot coordination and well-defined logistics because of the need for the market and the vendors to remain operational during the entire retrofit project.

“I met with managers of the market and vendors every day during our work there,” said House. “They always needed to know where we’d be so that everyone could remain in operation. The phone was ringing all the time, and we did most of our work at night. We also had to coordinate with all of the other trades. Adding to the challenge was the inability to store our tools and materials there.”

More than Meeting Code

“The market’s in an older building, so there was a lot of stuff on the ground and attached to the ceiling that had to be moved for us to complete the ventilation work,” added House. “The commercial ductwork was a fairly specialized installation.”

GTC pros installed hundreds of feet of 14- to 36-inch Selkirk kitchen grease duct with a zero clearance to combustible rating and integral chase construction. The high-temp, fiber-insulated, double-wall construction provides a two-hour fire resistance rating and eliminates the need for a separately constructed, fire-rated enclosure around the duct.

Also installed by GTC crews were eight 10-foot and two 8-foot Halton Capture Jet™ kitchen hoods, designed to efficiently eliminate heat and all emissions within the convected plume from all cooking spaces. All of the National Fire Protection Association (NFPA) Type 1 hoods, designed to remove heat, smoke, vapors, and grease, are served by a single, central fan.

Ritch Lewis, partner with the Cleveland-based Thermal Products Co., a manufacturer’s rep firm, explained that less exhaust is needed to remove the particulate- and moisture-laden plume seeking airborne status from the market’s many ovens, griddles, fryers, broilers, and wok ranges.

“When that effluent isn’t removed, which was the case before the new ventilation work was complete, it condenses and falls out of the plume, leaving smelly grease particulates everywhere — on clothing, skin, and in hair,” said Lewis. “That’s at the very heart of why this project began in the first place.”

Another key facet to Schlotterbeck’s design was an integrated fire suppression system. “If the ducting was a manifold-based system, the entire fire suppression system would need to be discharged simultaneously,” said Schlotterbeck. “But with Type 1 hoods, fire suppression is controlled independently at each hood.”

Rooftop-ready Solution

“Compared to the work we did inside the building, the actual installation of the new rooftop equipment was quite simple,” said House. “The Modine Atherion ventilation systems are sized ideally to fit into the old Aaon Inc. rooftop curbs, so there was very little prep work involved in swapping out the old systems with their replacements. We’re well-acquainted with the Atherion equipment,” added House.

The Atherion units specified by Dynamix are designed to meet ASHRAE 189.1 and 62.1 standards for IEER efficiency and IAQ. The systems also provide high-efficiency gas heating, MERV 16 air filtration, and the capability for 100 percent outside air ventilation for greater energy savings.

According to Schlotterbeck, the Atherion’s gas burners maintain more than 90 percent burner efficiency and operate with a 15:1 turndown ratio. This allows high-efficiency operation while maintaining discharge air temperatures during the heating season within a few degrees of set point.

“The make-up air units are specifically designed to vary the amount of outside air to the inside space,” explained Schlotterbeck. “A controls signal originating from the exhaust hoods and passed through the building automation system (BAS) to the make-up units ensures that they draw enough outside air while precisely tracking the amount of air evacuated by the central fan and kitchen hoods to maintain positive pressurization of the building.”

Up on the Rooftop

Through September and October of 2013, GTC crews worked evenings to complete most of the interior grease duct and kitchen hood installations. On an overcast day in November 2013, House and others from GTC arrived at North Market for the long-awaited opportunity to remove all of the old rooftop equipment, with ready replacements.

“We had to cordon off about one-quarter of the parking lot,” he said. “A small crane arrived to unload the rooftop units, curb adapters, and all of our other material. We needed a much larger 90-ton crane with a 120-foot boom to lift the rooftop equipment onto the roof because of the need to reach so far up, and in, from just one location on the ground.”

At 4 p.m., the building closed as the big crane cranked up for its first task and GTC crews waited in place to eliminate the old rooftop systems. As quickly as the old equipment came down, new curb adapters were fitted and preparations were made to line up the new supply and return ducts, gas supply, and wiring.

By 8 p.m., the big crane’s work was complete and one GTC crew remained behind to activate two of the new Atherion units and the big fan for morning operation.

Odor-free at Last

Several weeks ago, and about three months after completion of the market’s HVAC and ventilation retrofit, Oesterling returned to North Market with a couple of business associates. Ignoring the impulse to rush through, they strolled among the vendors, quick to see that larger crowds of people — many in suits and ties — were doing the same.

“Each of us ordered lunch from different vendors, and we enjoyed great meals inside. We all noticed a huge difference in the air inside the market,” he said. “It felt clean and fresh; we were in no rush to leave.”

The ultimate test was returning to the office, and then home, which revealed, at last, the market excursion proved to be an odor-free experience.

Information courtesy of John Vastyan, president, Common Ground. Contact him at

Publication date: 8/25/2014 

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