The Case Of The Exhausted Exhaust: A Lab Ventilation Mystery
Why was one floor’s laboratory ventilation failing to keep up, when it was even the closest floor to the rooftop fans? Some system sleuthing led two engineers to a fitting conclusion.
A colleague of mine was the project manager on a commissioning project for a build-out at a five-story, 150,000-sq-ft laboratory building at a large university. The commissioning team was finding it difficult to close out the commissioning process due to the poor performance of the exhaust air systems. The current construction project that they were commissioning consisted of the build-out of lab space on half of the fifth floor. The project had added about 40 fume hoods and now that construction was complete, the project could not be finalized because over one-third of the new hoods would go into a low-flow alarm condition when their sashes were raised beyond their minimum position.
The design engineering firm was under the belief that the central exhaust system, which was not modified during the construction project, was the cause of the issue. The project manager for the commissioning team realized that this issue could not be resolved until the root causes were understood. He requested that a coworker and I, who have experience in diagnosing complex building problems, visit the site and see if we could solve the problem.