Monday, March 21, 2011

Schools - Spending & Standards

I just completed a drive to South Florida from Dallas. I listened to public radio much of the way, and it was interesting that all 5 states I drove through had the same story. It seems that state revenues are down, and all are planning draconian measures to reduce spending on education. I see the same on national news, but you have to spend a little time in each state to get the local ‘flavor’ of the news reports.

In the past, when commercial construction was down, the state school construction budget always seemed to survive, and keep the local Architect / Engineer/ Contractor pipeline filled with projects. Not so any more, at least in Texas, Louisiana, Mississippi, Alabama, and Florida. I even heard that some schools are doing a rehab and (shudder) repainting diffusers rather than replacing them. That should, of course, be illegal (I jest).

On the other hand, school construction rules are tightening up, big time. Acoustics, often not well understood or simply ignored, is not going to be able to be ignored in the future. LEED for Schools, 2012, recently out for public review, proposes a mandatory 40 dBA limit in schools (about an NC=31), with strict rules for sound transmission through structure (STC) and clearly limiting reverberation time in the classroom. In reviewing the returned comments on this proposed mandatory requirement, there were no comments suggesting it was too strict. Indeed, a point can be gained for achieving 35 dBA (NC=26) in classrooms.

Meeting these requirements will be difficult. Traditional HVAC solutions including unit vents, small package rooftops, water source heat pump, ducted fan coils and even series fan powered VAV boxes cannot likely meet these new acoustical requirements. Florida is still paranoid about lined duct, which will be required if the sound levels are to be achieved. Displacement diffusers are certainly a valid solution, with the advantage of a reduced ventilation air requirement, but are often more expensive than conventional overhead air delivery.

The additional costs of complying with the new acoustical requirements may even preclude retrofits, as many codes require all retrofits to comply with new rules. It will be our children, of course, who will suffer in noisy and often over crowded classrooms.

Authored by: Dan Int-Hout, Chief Engineer Krueger