ASHRAE has put out a guide on the installation, design and use of underfloor air-distribution systems.

UFAD Guide: Design, Construction and Operation of Underfloor Air Distribution (UFAD) Systems includes details from new studies and experiments on the systems, along with insights from manufacturers and engineers familiar with their use.

Officials with the American Society of Heating, Refrigeration and Air-Conditioning Engineers says the use of such systems is increasing.

“There are many advantages to UFAD that make it an attractive building system solution,” said James Megerson, lead author of the guide and a member of ASHRAE’s technical resource group on underfloor air distribution. “It truly integrates the heating and air conditioning system with the entire building by utilizing common building materials as the air delivery means. The raised access floor allows accessibility to other building system infrastructure, such as power and data cabling, to facilitate easier space reconfiguration. Due to the lower system operating pressures and potential to expand economizer operation, the system has the potential to use much lower energy than ducted systems.”

The guide costs $89 for society members and $99 for nonmembers. For information, call (800) 527-4723 or go to