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Backdraught
A backdraft (North American English) or backdraught (British English) is the abrupt combustion, burning of superheated gasses in a fire, caused when oxygen rapidly enters a hot, oxygen-depleted environment; for example, when a window or door to an enclosed space is opened or broken. Backdrafts present a serious threat to firefighters. There is some debate concerning whether backdrafts should be considered a type of flashover (see below). Burning When material is heated enough, it begins to break down into smaller compounds, including hydrogen. This is called pyrolysis, and does not require oxygen. If oxygen is also provided, then the hydrogen can combust, starting a fire. If material undergoing pyrolysis is later given sufficient oxygen, the hydrogen gas will ignite, and therefore, combustion takes place. Cause A backdraft can occur when a compartment fire has little or no ventilation. Due to this, little or no oxygen can flow into the compartment. Then, because fires reduce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North American English
North American English (NAmE, NAE) is the most generalized variety of the English language as spoken in the United States and Canada. Because of their related histories and cultures, plus the similarities between the pronunciations (accents), vocabulary, and grammar of American English and Canadian English, the two spoken varieties are often grouped together under a single category. Canadians are generally tolerant of both British and American spellings, with British spellings of certain words (e.g., ''colour'') being favored in more formal settings and in Canadian print media; for some other words the American spelling prevails over the British (e.g., ''tire'' rather than ''tyre''). Dialects of American English spoken by United Empire Loyalists who fled the American Revolution (1775–1783) have had a large influence on Canadian English from its early roots. Some terms in North American English are used almost exclusively in Canada and the United States (for example, the term ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
