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In Barns, Measuring Air Movement Is a Breeze With FANS

By Hank Becker
July 15, 1999

Ventilation fans in animal barns and poultry houses are critical for delivering fresh air and removing heat, moisture and dust. But measuring a fan's performance has been difficult. So, Agricultural Research Service scientists designed and built FANS, short for "fan assessment numeration system."

FANS combines a portable anemometer--an instrument to measure wind speed--with a computer and software to record and analyze measurements. This system helps solve measurement problems that until now had not been technically feasible to fix.

Traditional techniques are cumbersome, inaccurate by 8 to 10 percent, and take 30 to 45 minutes. The anemometer in the FANS system can measure air-volume flow with 99 percent accuracy in less than 4 minutes, according to John Simmons and colleagues at ARS' Poultry Research Unit in Mississippi State, Miss. ARS is USDA's chief research agency.

Simmons and ARS colleagues assembled and calibrated the anemometer in cooperation with the Aerospace Engineering Department at Mississippi State University. It was validated by a major fan manufacturer in Bremen, Ala.

FANS can pinpoint the best location for ventilation fans. For example, fans placed at the end of a long poultry house are more efficient than fans along the side walls at the end.

The scientists have used FANS to study effects of fan shutters, exhaust cones, belt guards and propeller deterioration. They plan studies of light baffles, fan belt condition, dust and static pressure.

While primarily a research tool, FANS has many applications. It saved an egg company more than $200,000. The company had just installed belt guards on 1,100 fans in 115 poultry houses to protect employees from possible hand injuries. FANS showed that ventilation remained adequate with the guards installed; the company did not have to buy additional fans.

A story about FANS appears in the July Agricultural Research magazine and on the Internet at:


Scientific contact: John Simmons, ARS Poultry Research Unit, Mississippi State, Miss. phone (662) 320-7480, fax (662) 323-3535,