removal of ventilation to ceiling space

[ssylvest]

Should it pose a problem to remove the ventilators on the top of a commercial building. We have a 40 year old commercial building that will soon get a new roof (changing from a built-up roof system to a simgle ply membrane roofing system). The roofing contractor suggested removing the existing turbine "whirlybird" ventilators to save on flashing cost and leak potentials. He felt like they were not needed and he noted they are not on most similar buildings in shopping centers.

The building has a suspended ceiling (on track grid) with 2' x 4' ceiling tile panels that have about 1.5" insulation. Above those, all the HVAC ducts, sprinklers, and pipes are run. Then the roof is metal deck with lightweiht concrete with the built-up roofing on top of that.

Thanks for any advise or recommendations to other references.

 

[walkes]

The whirly bird ventilators are usually used to relieve hot air from large open spaces, or from attic spaces to keep air moving through it. If you need relief air from the space for some reason you may want to keep some of the openings. It would depend on what your design entails.

 

[MintJulep]

You should base your decision on an engineering assessment, not the advice of a roofing contractor.

 

[willard3]

There are a thousand reasons there are ventilators on the roof, among them pressure relief for an economizer system.

Find out why they are there and don't guess, hire someone who knows.

 

[Drazen]

As colleagues mentioned, it is almost certain those fans have important function, you will likely block complete HVAC function if you remove them, can be said even without looking at design.

Morevoer, roof fan installation has very little or no leak potential, any roofing contractor can seal edges of roof frames with typical application detail.

Most of roof tightness problems I have seen come from individual stack vents, the worst being vents with small diameter, though new syntetic, often polyethilene based, ply membranes made roof sealing much easier.