Pronunciation: [blˈak dɹˈaft] (IPA) 
The spelling of the word "black draft" is fairly straightforward. "Black" is spelled with the letters b-l-a-c-k, representing the sounds /bl/ at the beginning, followed by a short /a/ sound and a hard /k/ at the end. "Draft" is spelled with d-r-a-f-t, representing the sounds /dr/ at the beginning, followed by a short /a/ sound and a soft /f/ and /t/ at the end. The IPA phonetic transcription for "black draft" is /blæk dræft/.
Black draft refers to a catastrophic event that occurs in a burning structure, particularly in enclosed spaces such as buildings or vehicles, where a rapid ignition and combustion of hot gases results in an intense and explosive fire phenomenon. This phenomenon is characterized by a sudden inflow of fresh air into an oxygen-depleted environment, causing a rapid and violent escalation of fire to a previously unseen magnitude. As the air supply is abruptly reintroduced, the combustion process in an enclosed space changes from a controlled, oxygen-limited state to an uncontrolled, oxygen-rich condition, leading to an explosive chain reaction.
During a black draft, the sudden burst of oxygen causes a tremendous increase in temperature and pressure, leading to a rapid expansion of flames, intense heat, and explosive force. The outcome is a significant blast wave that can be highly destructive, capable of causing structural collapse, blowing out doors and windows, and endangering the lives of firefighters and occupants alike.
Given the immense energy released during a black draft, a powerful suction effect is created as the fire rapidly consumes the available oxygen. This suction can draw nearby flames, smoke, and debris towards the fire’s epicenter, exacerbating the conditions and further intensifying the inferno. The resulting phenomenon is often accompanied by a distinctive roar, similar to a freight train, as the flames feed voraciously on the fresh oxygen supply.
It is crucial for firefighting personnel to be aware of the potential occurrence of a black draft as they perform fire suppression operations. The sudden and violent nature of this event can present grave challenges and risks, requiring firefighters to be vigilant and prepared to execute appropriate tactical measures to prevent or mitigate its devastating consequences.
Infusum sennae compositum.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
