When responding to a chemical spill or other hazardous cleanup operation, first responders must frequently wear a level A hazardous materials suit. These suits protect the first responder from chemical exposure by completely sealing the wearer against external vapors and liquids. Because the suits are sealed, a fresh air supply is required which is typically provided by a self-contained breathing apparatus (SCBA). In total, the SCBA/impermeable suit provides contaminant free air and a barrier to the chemical hazard. Unfortunately, because the suits are sealed, they quickly get very hot and humid. Given the fact that a first responder can be in the suit from 30-60 min, overheating is not just a source of discomfort, but is a real hazard to the health of the first responder. In addition, perspiration condenses on the inside of the faceplate obscuring vision, and the heat/humidity buildup in the suit severely limits the time that can be spent in the suit without risking heat exhaustion. TDA Research, Inc. (TDA) proposes to develop a lightweight, portable system that will both cool and dehumidify the air circulated through a hazmat suit. TDA will use a heat exchanger to transfer heat from the inside of the suit to the dirty environment, but keeps the clean and contaminated air streams separate. The dry (about 15% RH) clean air is cooled to about 770F and returned to the first responder. The cool, dry air is distributed to the hands, head, and feet within the Personal Protective Equipment (PPE) with a lightweight fabric, internal duct system. In the Phase I project, we will design and build a test heat exchanger to demonstrate our concept. In addition, we will perform a system analysis using a 2D software and a finite element analysis. The design analysis will form the basis of the prototype fabrication in the Phase II project.
This research will allow first responders to work in hot and humid environments for long periods of time without being subject to the deleterious effects of over heating. The successful development of a cooling suit will find applications in other agencies of the U.S. Government.
