After a structural fire has been extinguished, firefighters conduct salvage and overhaul operations.

The primary purpose of these activities is to check for and extinguish any smoldering hot spots, while at the same time trying to minimize damage to the structure and its’ contents.

credit:

/>
In addition to the hazards associated with debris when taking down ceilings and the other functions involved with overhaul operations, there is considerable exposure to toxic chemicals, gases, and particulate matters during overhaul firefighting.

Often these chemicals, particulate matters, and potentially toxic gases present during the cold smoke environment may be inhaled, ingested, or absorbed through skin contact.

Early in the overhaul operations, firefighters normally wear their self-contained breathing apparatus (SCBA) as this is their only means of complete respiratory protection.

Later in the operations, it is common for firefighters to remove the SCBA when the carbon monoxide (CO) concentrations, measured by a handheld instrument, drops below the 8 hour Occupation Safety Health Administration (OSHA) permissible exposure limit (PEL) of 35 parts per million (ppm).

Firefighters remove their SCBA equipment because the overhaul environment is hot, the SCBA is heavy and cumbersome to work in, and must be changed periodically, approximately every 30 minutes.

Unfortunately, CO concentrations do not correlate with the concentrations of the multiple harmful chemicals that can be present in the overhaul environment, nor do they in any way indicate the hazards associated with inhaling particulates.

Structural firefighters and fire investigators need a respirator system that offers protection against the chemical and vapor hazards present in the overhaul environment.

The technology must be capable of protecting personnel present during overhaul operations from airborne hazards and carcinogens.

Prior development efforts by TDA Research and Avon Protection were successful in addressing this void by producing and delivering to DHS prototypes of the overhaul filters for an Operational Field Assessment (OFA), executed at the National Fire Academy in Emittsburg, MD in October 201 8.

Additional overhaul filters were also provided to DHS at the conclusion of the OFA.

Since that time, TDA Research and Avon Protection Systems are continuing development efforts of the overhaul filter which include additional testing of various carbon lots to ensure that if a lower capacity carbon lot is introduced the filter system would still offer the required user protection.

TDA Research and Avon Protection will develop a National Institute for Occupational Safety and Health (NIOSH)-certified stackable filter system that can be used as a traditional APR or with a powered air purifying respirator (PAPR).

This filter system offers fire personnel involved in overhaul operations protection against the inhalation of harmful vapors and chemicals present in the overhaul environment.