The Protective Performance of Process Operators' Protective Clothing and Exposure Limits under Low Thermal Radiation Conditions

Simple Summary Process operators have an important monitoring role in the petrochemical industry. In the event of process disruptions and incidents, a process operator is often the first responder and takes measures to diminish the effects of an incident. Thus, a process operator can be exposed to dangerous circumstances, and therefore personal protective equipment has to be worn. In case of fire, the operator may be exposed to high heat radiation levels. Previous studies have established maximum acceptable heat radiation levels for long- (>15 min) and short-term exposures (<5 min), these being 1.0 kW/m(2) and 1.5 kW/m(2), respectively. These limits were based on manikin measurements and physiological models. The validation of the protection of operators' clothing in human trials is lacking. Therefore, twelve professional firefighters were exposed to three different heat radiation levels in process operators' clothing. The experiments showed that the majority of the operators can be exposed for 5 min to 1.5 kW/m(2), up to 3 min to 2.0 kW/m(2), while exposure to 2.5 kW/m(2) or above must be avoided. Due to a slower skin temperature rise, loose-fitting protective clothing was related to longer exposure times. We speculate that additional long-armed/legged (under)clothing may offer more protection and extend the exposure time to heat radiation. During the early stage of a fire, a process operator often acts as the first responder and may be exposed to high heat radiation levels. The present limit values of long- (>15 min) and short-term exposure (<5 min), 1.0 and 1.5 kW/m(2), respectively, have been set using physiological models and manikin measurements. Since human validation is essentially lacking, this study investigated whether operators' protective clothing offers sufficient protection during a short-term deployment. Twelve professional firefighters were exposed to three radiation levels (1.5, 2.0, and 2.5 kW/m(2)) when wearing certified protective clothing in front of a heat radiation panel in a climatic chamber (20 degrees C; 50% RH). The participants wore only briefs (male) or panties and a bra (female) and a T-shirt under the operators' clothing. Skin temperatures were continuously measured at the chest, belly, forearm, thigh, and knee. The test persons had to stop if any skin temperature reached 43 degrees C, at their own request, or when 5 min of exposure was reached. The experiments showed that people in operators' clothing can be safely exposed for 5 min to 1.5 kW/m(2), up to 3 min to 2.0 kW/m(2), and exposure to 2.5 kW/m(2) or above must be avoided unless the clothing can maintain an air gap.