SCHOFIELD, Wis. — Greenheck Fan Corp. has come up with a new application for Building Automation Products Inc.’s (BAPI’s) Volatile Organic Compound (VOC) sensor. The company is literally using it to help clear the air at its main fabricating plant.

BAPI originally designed the VOC sensor as an alternative to CO2 sensors for demand-controlled ventilation, but a growing number of facilities with specific substance concerns are finding that it is a good solution for them as well. In this case, the offending substances were the byproducts of welding.

Greenheck is a leader in the manufacture of HVAC air movement and control equipment. Greenheck contacted BAPI last year while looking for a cost-effective way to improve air quality at its main welding facility in Schofield, Wis. Specifically, the company was looking for a way to control exhaust fans and bring in conditioned outside air only when necessary. The goal was to maintain good air quality and also save energy. BAPI’s suggestion to use the VOC sensor turned out to be a successful solution.

“There was a haze in the air at the plant,” said Brent Mattson, Greenheck manufacturing engineer. “We had complaints from staff about the haze even though the air quality was within OSHA-specified levels.”

Greenheck took the complaints seriously; especially considering recent findings that overexposure to two components in welding fumes, manganese and hexavalent chromium, can cause brain damage or lung cancer. While a VOC sensor does not specifically sense weld smoke or particulates, it can provide a way to maintain good air quality even in a welding atmosphere.

The 138,000-square-foot facility has 30 welding bays, each with a source capture hood venting air to the outside. There are also five rooftop exhaust fans and three makeup air units supplying conditioned air. Running all the vents at once all day was expensive and probably unnecessary, but Greenheck had no way to accurately measure if and when additional ventilation was necessary — until the company tried the VOC sensor.

Greenheck was able to use its team’s extensive HVAC knowledge and experience as well as its industrial controller to design a custom system. Now the hoods, fans, and makeup air units are all communicating with each other and with six BAPI VOC sensors located throughout the building.

“We’re saving money,” said Mattson. “And we compared the results of the air sampling with the new system to the OSHA standard and we’re well below the standard.”

The utility costs at the facility have dropped from 3.5 percent of the total cost to under 3 percent since installing the system, and Greenheck expects to recoup the cost of the project in about 1.8 years. The company also received a $12,000 grant from Focus on Energy to help offset the $40,000 cost of the project.

According to Mattson, the savings is nice, but keeping the staff healthy and happy is the most important part. “There is no longer any haze and no longer any complaints about the air quality,” he said.

For more information on BAPI’s VOC sensors, go to

Publication date: 2/3/2014

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