TABLE OF CONTENTS Floor diffusers are most commonly used and offer the widest selection of products to the designer. Due to growing interest in UFAD systems in the U.S., several new designs have been introduced in the last five years and this trend is expected to continue. Floor diffusers can be passive or active, depending on the plenum configuration and mode of operation (see below). TAC supply outlets that provide a wider range of control by the occupant are typically fan-driven (active) and may be located in the floor, furniture, partitions, or ceiling. Please see Chapter 5, "UFAD Equipment," for a more detailed discussion of diffuser options.
Passive diffusers are defined as air supply outlets that rely on a pressurized underfloor plenum to deliver air from the plenum through the diffuser into the conditioned space of the building. Active diffusers are defined as air supply outlets that rely on a local fan to deliver air from the plenum through the diffuser into the conditioned space of the building. Passive diffusers can generally be converted to active diffusers by simply attaching a fan-powered outlet box to the underside of the diffuser or grille. Most manufacturers provide both passive and active diffusers.
Three types of floor diffusers currently in use are:
Swirl diffuser: This is the most commonly installed type of diffuser in UFAD systems; more models are commercially available than for any other design. The swirling air flow pattern of air discharged from this round floor diffuser provides...
