Thermal imaging comparison of maximum surface temperatures achieved on N95 filtering facepiece respirators with and without exhalation valves at sedentary breathing volumes.
Monaghan-WD; Roberge-MR; Rengasamy-M; Roberge-RJ
J Int Soc Respir Prot 2009 Mar; 26(I-II):12-19
One of the purported benefits of exhalation valves on filtering facepiece respirators is increased wearer comfort through enhanced elimination of exhaled breath-associated heat to the environment, but published data attesting to the efficacy of these valves to accomplish this action is scant. This breathing mannequin-based study utilized infrared camera technology to examine the maximum surface temperature attained in two models of N95 filtering facepiece respirators with exhalation valves compared to two similar respirators without exhalation valves. No significant differences were noted when comparing respirators without valves to respirators with valves from the same manufacturer; however, respirators with valves, as a group, tended to exhibit a greater maximal surface temperature than respirators without valves (p=0.05). At sedentary breathing volumes of one hour duration, N95 filtering facepiece respirators with exhalation valves may offer no benefit in heat dissipation over that of similar filtering facepiece respirators without exhalation valves.
Respirators; Respiratory-protective-equipment; Personal-protective-equipment; Personal-protection;
Author Keywords: filtering facepiece respirators; exhalation valves; surface temperatures; infrared camera imaging
Raymond J. Roberge, Centers for Disease Control, National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory, 626 Cochrans Mill Road, Pittsburgh, PA 15236
Journal of the International Society for Respiratory Protection