Abstract: Sensor systems and methods are disclosed herein. A relative humidity sensor is generally associated one or more porous heating elements. A porous resistive material surrounds the relative humidity sensor. Additionally, one or more flat heating elements can be bonded to a base of the relative humidity sensor to conduct heat and insure uniform heating about the relative humidity sensor. The porous heating elements can be configured to permit humid air to pass through the porous heating elements. Also, the porous heating element(s) can be assembled slightly offset from a surface of the relative humidity sensor so that air that is saturated with water vapor passes through and is heated by the porous heating element in order to evaporate water droplets associated with the water vapor and thereby reduce relative humidity to a measurable level. The porous resistive material can be configured from a material such as, for example, tantalum or nichrome.

Abstract: An article for fire protecting a duct includes a first layer of a first material including a noncombustible fibrous material and a second layer of a second material including an intumescent material. The first layer is adjacent the second layer. The article is non-self-supporting and has an initial thickness of less than about three inches when in a first application condition, and an expanded thickness when in a second heated condition. The expanded thickness is greater than the initial thickness. At the expanded thickness, the article meets Section 5.5 of AC101 Acceptance Criteria for Grease Duct Enclosure Assemblies, as specified in April 2001 by the International Council of Building Officials (ICBO-ES).