設置常開或常閉,視排煙口的形式而定.當設常閉的排煙口時,排煙支管上設常開的排煙防火閥。當設普通常開型風口時,排煙支管上設常閉的排煙防火閥。當設常閉型專用防火排煙口時,則排煙支管上不設排煙防火閥。設置機械排煙的地下室應考慮進風設施,當采用機械進風系統時,應在風機入口管道上設置70℃熔斷的防火閥。
對于機械加壓送風系統,可在加壓送風機入口管道上設置70℃熔斷的防火閥,以防止新風入口受火、煙威脅,將煙氣輸送至樓層內。在排煙風機的入口總管上應設置當煙氣溫度超過280℃時能自動關閉的排煙防火閥,且應與排煙風機連鎖,當排煙防火閥關閉時,風機停止運轉。 需要說(shuo)明的是,排(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)防(fang)火閥設(she)(she)置在(zai)排(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)風機前、后,要依(yi)具體(ti)情(qing)況靈活確(que)定。以地下室排(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)系統為例(li).當(dang)地下室僅為一(yi)層(ceng)(ceng),且排(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)經豎風道排(pai)(pai)(pai)(pai)至室外時,排(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)防(fang)火閥宜設(she)(she)置在(zai)排(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)風機入口總(zong)(zong)管上.當(dang)地下室層(ceng)(ceng)數在(zai)二(er)層(ceng)(ceng)及二(er)層(ceng)(ceng)以上,各層(ceng)(ceng)共用一(yi)排(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)豎井(jing)時,則每(mei)層(ceng)(ceng)排(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)防(fang)火閥應設(she)(she)置在(zai)排(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)風機出(chu)口總(zong)(zong)管上,即緊(jin)靠排(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)豎井(jing)一(yi)側(ce)設(she)(she)置。
不論(lun)是(shi)豎向布置(zhi)的走道(dao)(dao)排(pai)(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)(yan)(yan)系統(tong)還是(shi)水平式(shi)布置(zhi)的房間(jian)(jian)排(pai)(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)(yan)(yan)系統(tong),均(jun)應在(zai)排(pai)(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)(yan)(yan)支(zhi)管與(yu)豎風道(dao)(dao)連接處設(she)置(zhi)280℃時(shi)(shi)能(neng)自(zi)動關閉的排(pai)(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)(yan)(yan)防火閥。排(pai)(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)(yan)(yan)防火閥設(she)置(zhi)常(chang)開(kai)(kai)或(huo)常(chang)閉,對(dui)于房間(jian)(jian)排(pai)(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)(yan)(yan)系統(tong),當負(fu)擔一(yi)個防火分(fen)區(qu)的排(pai)(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)(yan)(yan)管道(dao)(dao)帶多個防煙(yan)(yan)(yan)(yan)(yan)分(fen)區(qu)的排(pai)(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)(yan)(yan)口(kou)時(shi)(shi),應在(zai)該防火分(fen)區(qu)干管上設(she)常(chang)開(kai)(kai)的排(pai)(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)(yan)(yan)防火閥,同時(shi)(shi)各防煙(yan)(yan)(yan)(yan)(yan)分(fen)區(qu)支(zhi)管上設(she)常(chang)閉的排(pai)(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)(yan)(yan)口(kou)或(huo)排(pai)(pai)(pai)(pai)(pai)煙(yan)(yan)(yan)(yan)(yan)閥。