按噪(zao)(zao)(zao)(zao)(zao)(zao)聲(sheng)(sheng)源的時(shi)間(jian)特性分類①穩(wen)態噪(zao)(zao)(zao)(zao)(zao)(zao)聲(sheng)(sheng)：指噪(zao)(zao)(zao)(zao)(zao)(zao)聲(sheng)(sheng)聲(sheng)(sheng)壓級的變化(hua)較小（一般(ban)不(bu)大于(yu)3dB），且不(bu)隨時(shi)間(jian)有大幅度(du)的變化(hua)，南京降噪(zao)(zao)(zao)(zao)(zao)(zao)工程(cheng)，如(ru)電(dian)機、風機及其他電(dian)磁噪(zao)(zao)(zao)(zao)(zao)(zao)聲(sheng)(sheng)，固定轉速(su)的摩擦、轉動等(deng)噪(zao)(zao)(zao)(zao)(zao)(zao)聲(sheng)(sheng)。 ②非穩(wen)態噪(zao)(zao)(zao)(zao)(zao)(zao)聲(sheng)(sheng)：指噪(zao)(zao)(zao)(zao)(zao)(zao)聲(sheng)(sheng)強(qiang)度(du)隨時(shi)間(jian)而有起(qi)伏波動（聲(sheng)(sheng)壓變化(hua)大于(yu)3dB）。有的呈周期性噪(zao)(zao)(zao)(zao)(zao)(zao)聲(sheng)(sheng)，如(ru)錘(chui)擊(ji)；有的呈無(wu)規律的起(qi)伏噪(zao)(zao)(zao)(zao)(zao)(zao)聲(sheng)(sheng)，如(ru)交通(tong)噪(zao)(zao)(zao)(zao)(zao)(zao)聲(sheng)(sheng)。③脈(mo)沖(chong)噪(zao)(zao)(zao)(zao)(zao)(zao)聲(sheng)(sheng)：指持續時(shi)間(jian)小于(yu)1s的單個(ge)(ge)或多個(ge)(ge)突(tu)發聲(sheng)(sheng)組成的噪(zao)(zao)(zao)(zao)(zao)(zao)聲(sheng)(sheng)，環(huan)保降噪(zao)(zao)(zao)(zao)(zao)(zao)工程(cheng)公司，聲(sheng)(sheng)壓級原始(shi)水平(ping)升至峰值又(you)回至原始(shi)水平(ping)所(suo)需(xu)的持續時(shi)間(jian)短于(yu)500ms，其峰值聲(sheng)(sheng)壓級大于(yu)40dB。脈(mo)沖(chong)噪(zao)(zao)(zao)(zao)(zao)(zao)聲(sheng)(sheng)往往是突(tu)發的高強(qiang)噪(zao)(zao)(zao)(zao)(zao)(zao)聲(sheng)(sheng)，如(ru)火炮(pao)發射(she)等(deng)所(suo)產生的噪(zao)(zao)(zao)(zao)(zao)(zao)聲(sheng)(sheng)。

隔(ge)(ge)聲(sheng)(sheng)設計：隔(ge)(ge)聲(sheng)(sheng)墻：利用磚(zhuan)墻將發電機房封閉，墻厚240mm。隔(ge)(ge)聲(sheng)(sheng)門(men)：為保證(zheng)機房的(de)(de)(de)噪(zao)(zao)聲(sheng)(sheng)不被通道(dao)(dao)口外傳，降噪(zao)(zao)工程(cheng)施工，所以要在(zai)通道(dao)(dao)所在(zai)位(wei)置設置隔(ge)(ge)聲(sheng)(sheng)門(men)。門(men)體(ti)(ti)為雙層鋼板復(fu)合結構(gou)，內填(tian)吸(xi)(xi)聲(sheng)(sheng)巖棉，邊框在(zai)門(men)縫處包(bao)毛(mao)氈(zhan)，起到有效的(de)(de)(de)密封作用。管(guan)道(dao)(dao)、電纜穿(chuan)墻用超(chao)細玻璃棉填(tian)交，實(shi)施軟接觸，防止固體(ti)(ti)噪(zao)(zao)聲(sheng)(sheng)波(bo)傳播。吸(xi)(xi)聲(sheng)(sheng)體(ti)(ti)設計:吸(xi)(xi)聲(sheng)(sheng)天花(hua)：由于發電機的(de)(de)(de)噪(zao)(zao)聲(sheng)(sheng)是立(li)體(ti)(ti)的(de)(de)(de)往(wang)四周輻(fu)射(she)，而地面的(de)(de)(de)吸(xi)(xi)聲(sheng)(sheng)系數非常小(xiao)，它會把聲(sheng)(sheng)波(bo)漫反射(she)到吊頂的(de)(de)(de)天花(hua)。天花(hua)是采用吸(xi)(xi)聲(sheng)(sheng)天花(hua)龍骨，上鋪50 mm厚的(de)(de)(de)吸(xi)(xi)音(yin)棉作吸(xi)(xi)聲(sheng)(sheng)材料。穿(chuan)孔率>20%的(de)(de)(de)鋁扣(kou)天花(hua)板作為護面吸(xi)(xi)聲(sheng)(sheng)材料。

水泥廠噪(zao)聲(sheng)(sheng)(sheng)污染(ran)的分類(lei)根據噪(zao)聲(sheng)(sheng)(sheng)產生(sheng)的原(yuan)因，冷卻塔降噪(zao)工程，可(ke)以將(jiang)其(qi)分為3類(lei)：空氣(qi)動力性(xing)噪(zao)聲(sheng)(sheng)(sheng)：形成(cheng)原(yuan)因主要是空氣(qi)流(liu)(liu)(liu)動過(guo)程中所產生(sheng)的渦(wo)流(liu)(liu)(liu)、沖擊和壓(ya)(ya)力突變導(dao)致氣(qi)體的流(liu)(liu)(liu)動。如鼓風機(ji)、壓(ya)(ya)縮(suo)機(ji)、風機(ji)的進氣(qi)管道(dao)產生(sheng)的噪(zao)聲(sheng)(sheng)(sheng)。機(ji)械性(xing)噪(zao)聲(sheng)(sheng)(sheng)：生(sheng)產設(she)(she)備的零(ling)部(bu)件在其(qi)運(yun)行過(guo)程中會發生(sheng)互相撞擊、摩擦(ca)，產生(sheng)的交變機(ji)械力引起設(she)(she)備金屬(shu)板、軸(zhou)承或齒輪等其(qi)它部(bu)件的振(zhen)動，從而形成(cheng)噪(zao)聲(sheng)(sheng)(sheng)。其(qi)它噪(zao)聲(sheng)(sheng)(sheng)：如電磁元件產生(sheng)的噪(zao)聲(sheng)(sheng)(sheng)。電動機(ji)、變壓(ya)(ya)器由于電磁渦(wo)流(liu)(liu)(liu)、磁場振(zhen)動等因素而產生(sheng)的振(zhen)動輻射終會出(chu)現噪(zao)聲(sheng)(sheng)(sheng)。