Advantages of Using a Negative Pressure Respirator Hood: Guidance On The Use Of Hoods With Chemical Protective Respirators And Chemical Protective Suits [open pdf - 292KB]
The U.S. Army Soldier and Biological Chemical Command (SBCCOM) conducts tests to measure the protection that chemical protective ensembles provide against vapor exposure of the skin. These tests are called Man-In-Simulant Tests (MIST). Although a negative pressure respirator hood does not significantly increase respiratory protection, it does protect the skin about the head and neck from vapor exposure. This is particularly true when the respirator hood is worn in combination with a suit hood. Our testing shows that when the respirator hood is tucked down into the neck opening of the protective suit, and the protective suit hood is worn over the respirator hood, protection against vapor exposure is significantly increased. We call this hood configuration double-hooded. The double-hooded configuration significantly reduces vapor exposure about the head, neck, ears, and backs of the cheeks. In these body regions, the skin absorbs many vapors faster than it does in many other body regions. Therefore, vapor exposures about the head present greater hazards than vapor exposures in many other regions of the body. Wearing a suit hood over the respirator hood, with the respirator hood tucked down into the neck opening of the protective suit, provides significantly better protection of the overall individual against vapor exposures. We recommend that a negative pressure respirator hood always be worn with Level C chemical protective suit ensembles, even if the suit has an attached hood. When used in the double-hooded configuration, two protective hoods are better than one for skin protection about the neck and cheeks.