Consulting-Specifying Engineer - September 2008 - (Page 14)

M/E Roundtable Cooking up ventilation PARTICIPANTS This month’s panel discusses ventilation best practices in commercial kitchens, including codes and standards, and different energy saving and techniques. BY PATRICK LYNCH, Contributing Editor CSE : What actions or product applications help prevent grease fires in kitchen ventilation systems? Peter D’Antonio, PE President PCD Engineering Services Inc. Longmont, Colo. Tony McGuire, PE, FASHRAE President McGuire Engineers Inc. Chicago Steve Melink, PE President Melink Corp. Milford, Ohio Brian Rivet Sales & Marketing Mgr. Kitchen Ventilation Systems Schofield, Wis. Peter D’Antonio: Most grease fires are a result of poor maintenance of the exhaust system. Grease fires are avoidable through proper operation and maintenance. A good O&M plan will ensure the system is properly air balanced, makes provisions for kitchen staff to perform routine maintenance, and contracts qualified outside services to inspect and clean the grease exhaust system periodically based on the amount of effluent produced and filtration in place. Steve Melink: I think canopy-style hoods should be less susceptible to grease fires since they hang higher above the cooking equipment. The greater the physical separation between the heat source, boilers, the fuel source, and the grease-laden filters, the less likely an ignition will occur. Using the same logic, cooking equipment that is only 36-in. high is better than similar equipment that is 72-in. high. In addition, there should be horizontal duct runs, so that grease is less likely to collect on the bottom wall and become a potential fuel source in between cleanings. Brian Rivet: Capturing and removing the grease particulate at the hood will prevent hood plenums and ducts from building up substantial quantities of grease between scheduled duct cleanings. When capturing the grease near the source, the risk of grease fires in the ventilation system lessens. Select grease filters that have been tested to the ASTM F2519-2005 standard to understand the filter efficiencies and best match them to the cooking operation. Standard baffle filters will not provide efficient removal of grease particles from the airstream in most applica- tions, especially on high-grease-producing cooking operations. Opt for other mechanical filters such as centrifugal filters and dual stage filters. Tony McGuire: I do not know of any particular venting applications that will avoid grease fires because they are generally the result of inadequate maintenance or mistakes made on cooking lines themselves. This is why new requirements for cleaning and maintenance were included in the 2008 edition of NFPA 96, “Ventilation Control and Fire Protection of Commercial Cooking Operations.” CSE : When are VFDs on kitchen fans appropriate? McGuire: VFDs can be excellent methods of reducing operating costs when the kitchen design provides the right opportunities for modifying flow rates; however, many kitchens do not have the ability to do so. This becomes a matter of kitchen operations. A key question is, “What are the skills of the staff that will be turning equipment on and off?” Then, to determine whether VFDs are appropriate, you must look at the entire restaurant’s HVAC design as to how air will be moving during the course of a day’s operation. While the large chains have studied and developed many engineered approaches to ventilation and exhausts, the smaller, independent businesses continue to have little to no knowledge on the matter. D’Antonio: VFDs are appropriate where the kitchen exhaust must run continuously, but the cooking operation has a high diversity of operating schedules and appliance type. If appliances are idle a majority of the day, there is good potential for a VFD to reduce energy use. A primary consideration is that the 14 Consulting-Specifying Engineer • SEPTEMBER 2008

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Consulting-Specifying Engineer - September 2008 Contents Viewpoint Letters News M/E�Roundtable Selecting Appropriate Egress Strategies Commissioning On-Site Electrical Systems Mentoring Control Engineers and Technicians Casting Call for Cx Case Study New Products Equipment Lifecycles Advertiser Index Green Space

Consulting-Specifying Engineer - September 2008

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