The objective of this project is to determine available safe egress time in a single-story occupancy using a fractional effective dosage analysis with variable exposure for fast and slow growth fire scenarios. Required safe egress time was calculated using smoke alarm activation times from single-story residence fires in conjunction with human behavior and movement data for walking and crawling. Available safe egress time was calculated using a fractional effective dosage analysis with temperature and heat flux measurements as well as CO, CO${2}$, and O${2}$ concentrations throughout the structure. The two time quantities were compared to determine if safe egress was possible. Egress was possible in all scenarios where a smoke alarm alerted quickly. When egress was dependent on a smoke alarm located behind a closed bedroom door, egress was not possible for all fast growth fires and unlikely in most slow growth fires. However, the benefit of sheltering behind a closed door was significant when compared to an occupant's exposure without a bedroom door. This project shows the need for the installation of multiple smoke alarms within a structure.