Thermal response to firefighting activities in residential structure fires: impact of job assignment and suppression tactic

Abstract

Firefighters' thermal burden is generally attributed to high heat loads from the fire and metabolic heat generation, which may vary between job assignments and suppression tactic employed. Utilising a full-sized residential structure, firefighters were deployed in six job assignments utilising two attack tactics (1. Water applied from the interior, or 2. Exterior water application before transitioning to the interior). Environmental temperatures decreased after water application, but more rapidly with transitional attack. Local ambient temperatures for inside operation firefighters were higher than other positions (average ~10-30 °C). Rapid elevations in skin temperature were found for all job assignments other than outside command. Neck skin temperatures for inside attack firefighters were ~0.5 °C lower when the transitional tactic was employed. Significantly higher core temperatures were measured for the outside ventilation and overhaul positions than the inside positions (~0.6-0.9 °C). Firefighters working at all fireground positions must be monitored and relieved based on intensity and duration. Practitioner Summary: Testing was done to characterise the thermal burden experienced by firefighters in different job assignments who responded to controlled residential fires (with typical furnishings) using two tactics. Ambient, skin and core temperatures varied based on job assignment and tactic employed, with rapid elevations in core temperature in many roles.

Airborne contaminants during controlled residential fires

“…Temperatures inside the structure were measured using strategically placed thermocouples. [30] The maximum temperatures near the inlet of the tubing during the fires were 114-198°C, while temperatures at the location of the sampling media (outdoors) ranged from 13-20°C. Condensation of vapors to the tubing walls would explain why apparent losses were greater for the more volatile PAHs (those likely to be in gas-phase during collection) than the non-volatile PAHs (those likely to be in solid-phase).…”

“…Time of dispatch for attack firefighters was a median of 4.5 min after ignition, and water was applied to the fire a median of 6.5 and 7.3 min after ignition for transitional and interior attack, respectively. [30] Hence, personal air samples that did not run for at least 3 min of the response were excluded because they may not represent the average concentrations during the most critical phase of the response (including suppression). This resulted in the exclusion of 6 HCN, 3 VOC, and 2 PAH personal air samples (data provided in Supplemental File).…”

“…The study design is described in detail elsewhere. [25,30,31] Briefly, using a repeated-measures design, study participants were grouped into 6 crews of 12 firefighters and each crew was deployed to a pair of fire scenarios using 2 different fire attack tactics (order of introduction was balanced). Six fire scenarios were suppressed using an interior attack from the "unburned side" (advancement through the front door to extinguish the fire) and 6 fires were suppressed with transitional attack (water applied into the bedroom fires through an exterior window prior to advancing through the front door to extinguish the fire).…”

“…[30] The 2 bedrooms where the fires were ignited were furnished with a double bed (covered with a foam mattress topper, comforter and pillow), stuffed chair, side table, lamp, dresser, and flat screen television. The floors were covered with polyurethane foam padding and polyester carpet.…”

“…Still, many departments are seeking guidance on when conditions are such that respiratory protection may no longer be necessary in an attempt to balance firefighter's risk for chemical exposure and heat stress. [30] More work is needed to fully characterize the hazardous atmospheres encountered by firefighters. The materials found in 21…”