Breathe easier: Conduct an exhaustive search on exhaust systems

Breathe easier: Conduct an exhaustive search on exhaust systems – Statistical Data Included

Foster Frable Jr.

Being able to install a food facility in a building where no traditional exterior exhaust is possible has become a “holy grail” for scores of foodservice operators looking to enter nontraditional sites.

Exhaust restrictions may be due to architectural or structural limitations, landlord restrictions or local codes. The challenges of meeting local code requirements have become even more onerous than standard NFPA grease exhaust requirements, particularly in areas like Southern California and Michigan.

Fuzio Universal Pasta, a West Coast-based pasta concept experienced that challenge firsthand when it opened a roughly 100-seat restaurant on the first floor of a renovated retail-and-apartment building just north of trendy DuPont Circle in Washington, D.C.

The area is full of upscale restaurants, coffee shops and other retail establishments, most of which are located in historic or architecturally significant buildings. The building owner would not allow Fuzio to install an exhaust system through the various apartment levels to reach the roof. Local codes did not permit a side wall exhaust because of the living spaces located above. Therefore, the operator needed to find a creative solution in order to open the restaurant in that location.

The Fuzio menu demands a traditional saute/broil/fry cooking line that is exhausted with a common filter hood. The hood exits through the floor into a basement that has a small parking area with large louvers on the open side by the rear to provide standard ventilation. One of the parking spaces contains a packaged air scrubbing and grease removal system manufactured by Trion.

Hot, greasy, smoky air enters one side of the rectangular unit; warm, completely clean and odorless air comes out of the other end into the parking garage. An exposed concrete-block exterior wall that is located about 8 to 10 feet across from the exhaust discharge of the Trion unit shows no signs of grease or discoloration after six months of use.

What makes this unit particularly unique is that it is used with a standard off-the-shelf filter hood; no water-wash and water-mist system is required. It also was installed in a chain restaurant with a limited equipment budget, not an institutional or on-site setting. The Fuzio exhaust system is a representative of two general types of self-contained packaged environmental units.

Self-contained filter ventilation systems. Internally filtered air is discharged in the spaces where the equipment is used. The local systems are useful for kiosks and small food operators located in large-volume spaces like lobbies, stores or other retail facilities. Internally filtered air also is discharged out of the side of a building, a level below the roof line, or as in the case of Fuzio, into a basement parking area. Those remote systems are useful for situations where it is not necessary to bring the filtered air back into the cooking area but still must be exhausted at some external part of a building.

Both can be challenging when used in restaurants or office spaces where the air is recirculated and not exhausted at all or exhausted to remote areas, particularly when used with strong aromatic products like onions and garlic.

Basically, air pollution control is achieved in one of two ways or in combination. Each method has its pluses and minuses and directly relates to the cost of the systems purchased and the operation.

The systems may use a series of filters or may include electrostatic participators. The principle of electrostatic precipitation is not new. Basically, the grease and smoke particles are electrically charged and then picked up by the collectors as a magnet would pick up metal shavings.

The systems aren’t practical with gas-fired equipment or items producing significant smoke, such as a charbroiler.

Air quality will continue to be a major “hot button” in the United States and around the world as we approach the new millennium. Whether concerns are under- or over-estimated, foodservice pollution control takes on a special meaning because it’s about not only volatile contaminants like grease and smoke but also the most offensive and distasteful of all odors. Thanks to scientific laboratory technology, we as foodservice operators have several innovative alternatives to resolve some difficult ventilation quagmires.

Let’s say you are a chef-owner of a small bistro, and a local preservation society offers you a fantastic high-visibility space on the main floor of a beautiful historical building. You still have one problem: You can’t install ductwork through the roof because landmark status prevents you from changing the architectural integrity of the structure. What if you were the owner of a small noncommercial foodservice company, and you had just been offered a big B&I account in your city? You still have a problem: The building is 30 stories tall, and the only area to which you reasonably could vent your hoods is a parking area adjacent to your space.

All of those situations are real, but they don’t have to mean abandoning the operation if the right planning and budgeting are done from the start.

The goal of all the systems is to filter out the “big three” pollutants: grease, smoke and odor.

Grease. All professionals agree that the grease extraction efficiency of the primary exhaust and hood system before it reaches the pollution control device is key to the effectiveness of any system. The next step, smoke removal, and the last step, odor removal, are all connected. Even the life of the odor abatement material is extended by making sure that the hood filters are cleaned properly at regular intervals, whether via self-contained water-wash systems or simply by passing the grease filters through the dishwasher.

In most units filters or prefilters are used that are made up of wire mesh or cloth panels that remove particles larger than 10 microns in size, 1/2500 of an inch.

It’s important to understand that the strength of the system is in its proper sizing for the type and volume of cooking that will be produced. You could have a very small compact kitchen producing breakfast, lunch, and dinner in a busy hotel, compared with a spacious church kitchen with low production.

Smoke. Smoke generated from cooking food comprises very small particles the size of .3 to .8 microns. The air passes through an ionizer, which electrically charges the particles. It is in this stage that the greatest filtration occurs in the entire process. As the positive charged particulate is then carried over the collector cells, with alternating opposite or grounded charge, it is collected much like a magnet would pick up metal shavings. The cells are placed from three-eighths to three-fourths of an inch apart. The distance may affect how often they require cleaning but also may affect performance. The process removes the smoke color from the air. The units have water-wash systems before and after the prefilter and the ionizer. For the cells manual washing is possible and can be contracted by an outside service. Automatic cell-washing systems also are available. Trion’s self-cleaning system comes with a holding tank and valve that regulates the detergent mix with the water using 1.2 gallons of detergent mix per cleaning cycle in a 6,800-CFM unit. A service agent should clean the unit every nine months to maintain optimum performance.

Cooking odors. They are produced by the cooking of protein and vegetable matter and comprise a complex mixture known as ROGs or Reactive Organic Gases. The ROGs, which include carbon monoxide, cannot be removed by mechanical or electronic means. Some of the particles are contained in the grease, but the vast majority are still in the airstream. Odor abatement works in conjunction with the electrostatic precipitator using a bank of activated charcoal or carbon filters or a triple-filtration system. They can remove more than 200 different volatile organic compounds.

The triple-filtration type uses the following: first, polyester padcarbon powder bonded to the fibers, for light-to-medium filtration; second, carbon web-carbon granules in a nonwoven matrix for medium filtration; and third, granular carbon panels for high filtration.

The filters absorb and retain the odor molecules and must be changed. Another common odor abatement medium is known as potassium permanganate, which quickly oxidizes the molecules when they begin to change color. Once they have completely changed, they are no longer able to remove the containment and must be changed. One difference between the two is that the carbon type, if not changed when saturated, could pose a possible fire hazard.

The cost of the systems cannot be calculated by x times y equals z. Several factors are involved, including what the appropriate CFM rating of the exhaust is and whether they use automatic self-cleaning or manual cleaning. An electrostatic precipitator unit for a pizza oven with a 1,600-CFM requirement can be purchased, installed and ready to go for about $10,000. A 1400-CFM unit with a self-cleaning system can run about $16,000, and a 18,600 CFM unit could cost $35,000. Because the technology is what you are really paying for, the units actually get cheaper as they get bigger.

Difficult ventilation challenges don’t have to mean abandoning a project location. Some real dilemmas facing foodservice operators have proven solutions, Although at first glance some of the alternatives may seem somewhat costly, realistic planning in the earliest stages of a project can mean success.

COPYRIGHT 1999 Lebhar-Friedman, Inc.

COPYRIGHT 2000 Gale Group