One of the laboratories needed a canopy hood and rooftop stack system to capture and exhaust odors and fumes created during the research experiments. Previously, the university's physical plant engineering department had built its own custom hood stacks on site, but limited space, funding, and time prompted the project estimator at TTU to look into other options.
External funding was available if the university could find a way of completing the project during the time frame in which the funding was available.
Mike Halley of David G. Halley & Co., Greenheck's representative in Lubbock, reviewed the merits of Greenheck's laboratory exhaust system, TCB-LE, with Don Gamel, project estimator with the TTU engineering staff. Because the building had not been designed originally as a science building, there was very limited space on the roof for lab exhaust systems.
After reviewing the information on the Greenheck laboratory exhaust system, Gamel and Halley got together with Mike Powell of Anthony Mechanical, a mechanical contractor from Lubbock. All parties agreed that Greenheck's lab exhaust system was the right choice for the project.
The TCB-LE's compact footprint not only preserved valuable roof space, but it also required only a single roof penetration, Gamel said. He added that another benefit was the unit's stack is engineered to not require any unsightly guy wires. The TCB-LE served as a cost-effective alternative to standard field built-up fan and stack assemblies. In addition, the one-piece TCB-LE met ANSI Z9.5, UL 705, and ASHRAE lab design guidelines.
Ease Of MaintenanceIt was also important to TTU that its staff could easily maintain the equipment. "Whenever we add new equipment, we always look at maintainability as a general rule, and with so many stacks on the roof up there, it looks like a forest. We wanted something that could be easily accessed," said Gamel.
He also noted the fact that the unit doesn't require guy wires was key. According to Gamel, the unit provides safe, easy inspection and maintenance of internal fan components. By removing one access panel, service to the fan wheel, shaft, and bearing assembly is accomplished without removing the fan from the system.
A high-velocity exhaust cone incorporated in the TCB-LE displaces hazardous or noxious laboratory fumes high above the roof, preventing roof damage and re-entry of exhaust effluent into the building's make-up air system. An optional bypass air plenum and damper adds ambient air to the exhaust, to further dilute fumes, and provides additional exhaust displacement or allows the TCB-LE to be applied to variable volume lab exhausts.
The university's new laboratory exhaust system now exceeds design and engineering specifications and space considerations.
"I was really happy with the way it went in. Normally we've used the built-up stacks, but this one piece of equipment makes things simple. It's a good compact solution," said Gamel.
The TCB-LE lab exhaust system was specified, built, shipped, and installed within six weeks - well within the deadline to qualify for the external funding to cover the costs for this project.
Publication date: 09/05/2005