The SSEPD Series Perimeter Slot Diffusers are specially designed to provide an air curtain for operating rooms. The SSEPD Series unique slot design creates a continuous curtain of air, angled outwards 5º – 15º, that encloses the operating area and minimizes the possibility of contaminated air entering the surgical area. The double slot design creates a uniform velocity curtain that minimizes entrainment of contaminated air into the curtain air stream. It also creates a wider velocity profile with less turbulence and hence less induction over similar two slot designs. The face design also incorporates longitudinal deflectors that horizontally deflect a small amount of air lengthwise thereby joining sections and corners with a truly continuous curtain, resulting in enhanced isolation of the surgical area.