•'H!IIWii|-EMI NGUYEN NHAN, BIEN PHAP KHAC PHUC HIEN T U O N G vcf VOI KHI CH0A CHAY
Dai uy, ThS. PHAM THU HA Phdng 1. Trddng Bai hoc PCCC Thieu uy TRAN IVIINH HOANG HA Khoa 1, Trddng Dai hgc PCCC
Hi^n tUQing v9 voi, d'ng, bong khoa hoac hif hai c ^ thiet M bfCtri tr&n d\iitng oDg he thd'ng cung dTp nuTdC chiia chay xay ra kha [di6 bi^n l^m anh hifdng td! c$t ap, liAi liA^ng mtdc chO^ chay, giam hi^u qua chOia chay, tfln kem kinh t^... Hi^n tif0ig vd voi nky thufftig duf^c giai thich bWg ly thuySt v^ hi^n tifdhg va d$p thijy bic. Qua nghi&n cilki nguyen nhSn, chung ta se diJia ra U^n phap phong tdinh hvlu hi^u.
Va dip thiiy Igc la hign t i ^ g thay dfli ap suat dgt ngflt khi v^n ^ cia dflng eh;^ tSng hay giim dflt ngflt Chdt long dang ehuydn dflng va \ ^ tflc Ifln trong flng, ndu dong khfla lai mflt each dflt ngflt ttil ap si£it tinng dong chE^ (tnict tign tai vj trf sat khfla] se ting vpt Ifln, do ia hign tupng va dgp thiv lUc dUbng.
Ngupe lai, neu chit Iflng tmng flng dang fl trang tiiai ti'nh duflf ap s i # H^, ta mfl khoa dot ngflt iam chit Iflng dot nhign chuyen dflng vflf Vfln tflc ifln, ap suit trmg dflng c h ^ (tniCt tign fl vj tn sat khoa) se tgt h ^ gE^ ra hign tupng va dgp thiy lyc am.
Khi dflng chtiy tmng fihg chju tae dgng eie m ^ cflt ap kha eao, hign tiipng va dgp thiy lgc Xc^ ra cdng manh, cfl thd gc^ hong khfla, vS fihg, vfli hc^ iam hu hai cic thifit bj bfl trf trfin duflng flng. Trang cac hg tiiflng tmygn dflng, tmydn luc, hign tanig dfl efln g ^ ra maeh dflng ap s i ^ iam chg chd dfl iam ^gc da chirg mift fln djnh.
Nguygn nhan ^ g ho^c gi^m ap sudt trong va dgp thif/ lye la Igc quan tinh vflf vgn tflc thay dfli ddi ngflt. U t quan tfnh lufln lufln ngugc chilu vfli gia \ac. Vi ^ , n ^ \ ^ tflc giam till luc q u ^ tinh tae ding theo phUdng dflng chdy va vgn toc Qng thi ngudc l^u.
Phln tfch hign tiipng va dip thiy lyc sinh ra trang ong thing din chit Iflng tfl mflt bd chfla kha Ifln, cu^ flng cfl mflt khfla K.
Tm& khi dflng khfla, vgn ^ trang fl'ng la v^, ap aiit ^ khoa K la pQ va VI thflng chfla Ifln ngn cfl till coi ap siet ^ A (tai migng vao cia flng) la p^ = yH = const trong suflt qua trinh bigt ddi ap suit sau nay.
Ndu dflt ngflt dong khoa lai thi Iflp chat Iflng MNM,N, rdt mflng (AS) ding lai. Nhung tcan bfl lop chit long do khflng ding lai dflng thcii ma mat MN sat khfla K dung lai tniflc tifln con mat M^N, tidp tuc b| eae Iflp chEft Iflng phfa sau nen lai va sau thfli gian At nfl mfli dflng lai hoan toan. Do Iflp chit long MNM^N^ bj nen lai ngn trang tiifll gian At ap s i ^ tang Ifln thanh p^ + Ap.
Phubng trinh dflng lupng eo dang: RAt = m.Av Trong khoSng thfli gian At, Igc F = Ap.m va khfli lugng Iflp chat Iflng dfl la m=p.to.AS.
VI thd Ap.(fl.At = p.ai.AS.(v^-0) => Ap=p.^.v„ (i) Sau dfl, trang mflt khoang thfli gian vfl cflng nhfl At tidp theo, lai cfl thgm Icp chit long M,N,MjNj ding lai va ap siHt tai dfl tang lgn. Cac Iflp chS long tidp theo cirg v^. Cfl nhu thd, hign tugng chj& Iflng bj nging chay va b| nen lai (Bng ap suit) lan ddn vg phfa diu ong vflt van ^ la:
v = l i m — (2)-Tflc dfl tniygn sangva dap thiv lit.
ii-m At
Thay(2)vao{l),tae6: Ap = p.v.Vo h ^ ^ - ~ . v .
N h u i ^ , sau thfli gian t , — (3) (L ehieu dii flng), ap s i ^
V
trong toan flng tang lgn, toan bp chit long trong fihg fl trang thai ding ygn va bj nfln t i t thfli. Qua trinh ap sieft tang vgt kdt tiiue.
Cac dying flng, thigt b| tmydn nuft tiiuflng bj vd, hu hong tai VrH didm nay.
D ^ vao cfing thit (3) ta ti)^, thfli gian dong, mfl Idua bxng du&ng voi hay tang/giSm ap may bdm cang nhanh thi vgn tflc dong c h ^ cang Ifln va theo cfing thit (1), lucng ap siift ^ g Tgp chl Phong chay & Chiifa chay [^35 [
HGHIEH cuu B TRAP BOI |
lgn dflt ngflt rdt Ifln din ddn hifln taiflig va dap thiy lyc x ^ ra cang manh.
Hlnh: Vdi vdgan dSu na - ncf thi^g t^ khda, ba chac,
ISng chda chiy Thit td, dfii vfli cac duflng flng cip nuft trong cac hg thfing cip nub: sinh boat, Scin xu^ hoac duflng fihg trong hg thflng cing edp nu3c chfla c h ^ cfl djnh deu du(t lip dat cac tiiidt bj nh^m han chd va khie phgc hign t^ng va dgp thiv Igc nhu: van giam ap, van xa ap, gidng, binh diiu tifit...
Tuy nhign, trong cflng tac chidn ddu cie lyt; lugng canh sat PCCC, cac h^ tiiflng tmydn nuct m ^ bom - dubng voi chua dupe trang bj thidt b[ dliu tidt nay. Bgn canh dfl, cin bfl chidn ^ khi iam nhigm vg sfl dgng ISng, va, xe, may bdm chfla c h ^ tham gia ch\^ c h ^ do ehua hidu vg hign tugng va dgp thDy Igc, dflng thfli, mflt phdn do tfnh chit eflng vigc ygu eiu khdn tmtng ngn thuflng khflng thuc hign ding quy trinh, thao tac sai, tao diiu kign phat sinh hign tipng va dip thLv luc nhu trgn, din ddn su cfl vfl voi, vfl dUBng flng thuflng xuygn xSy ra.
Hign nay, Igc lugng CSnh sat PCCC ttiuflng dugc trang bj cae loai vfli chua ehgy dugc iam bSng vgt ligu la vfli vai trang eao su, cfl ap Igc iam vigc khoang 10 - 16 Bar, tiigm chf efl toai co thd chju dupc ap suit lgn den 50 Bar. Song, trong qua b'lnh sir dmg, Iflp vai bgn ngoai bj ngam nuflc lau, phd riQ nhigu lin, phdi ning nhigu nfin myc din; Iflp cao su bgn trong ran nflt, khflng efln kha ning ehju lgc, tinh din hfli giam. Khi iam vigc vCI ap suit thay dfli dflt ngCt, yJsj ra hign tijcng va dgp tiiLv Igc, se d l
dang g ^ bgc, vQ vfli.
Dd tranh hign tg(ng n^^ x ^ ra ti^n dubng voi ehfla c h ^ khi tridn khai chifa chiy, can ehfl y m^ft sfl van d l sau:
Phai tian thu tiieo quy djnh cia Dieu lgnh chila c h ^ CIB lye lugng Canh sat PCCC: Trang tridn khai VOI chila chJv. dufing vol chfnh can tridn khai dubng va cfl dubng kinli Ifln (d=66 mm, d=77mm), d i ^ g voi nhanh tiy thuflc vao yeu da ve luu lupng va cflt ap chOa c h ^ . Vi dfli vfli dubng voi cfl dubng kfnh eang Ifln thi vgn tflc dong chay cing nhfl, do tang ap
^ Ig va giam v^n tflc.
Khi tii&i khai dubng vfli chfla c h ^ trong digu kign cho phep cin phai ngin nhit, tuy nhign cin tranh eac vj tri cfl dfl doc eao, djc bigt doan voi 6 gan bdm, tranh dd Idiflng khf Igt vao duing vfli hi^c tao mfli tmfeng chan khflng trang dubng voi nhim khir va d?lp h c ^ de giam bflt cuflng dfl va dgp.
Phai tuan thu chidn thii$t chiEi ch% nha cao tang, eo sfl dgng nhiiu ba chac. Khi thu hfli phuong tign, d£S vfli dubng vfli chfla chay cac dam c h ^ fl vj tn' cao, khfla dubng voi ein khfla lin lugt tir vf tri cao nhdt (gin ling chifa ch^) xuong tiidp din (qua eae ba chac) d ^ bdm, n h k i giam ap lyc cflt nuec, giam cuflng dfl va dgp thuy IUC-
Thidt kd, lip d ^ thidt bi xa ap 6 diu lang chifa ch^^ dd tranh hign bjong va dap thi^ Igc lam hflng lang khi dong, mfl khfla lang.
Khi dflng, mfl eie khfla, van trfin duflng vM; lang, gi&m ap cDa xe, m ^ bom phai ttigc hign tiiao tac mflt each tfl tfl, trinh thao tac dgt ngflt.
Dfil vfli cic dubng flng, voi cfl ap Igc Ifln [ ^ tiiidt kd cac van k i ^ xoay, khflng thidt kd cac van dflng, mfl tflc thfli.
Dung nhung tiiifit bj tydflng tiiao chit Iflng trgn dubng flng thuflc h^
thflhg eung cip nuflc chifa ch£v ra khi ip suit vugt nguflng gifli han cho phep CIB dutng vfli (van giairi
ap, xa ap...).a
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'rong thuc td, boat dpng CNCH da chl ra rang cac chidn sy CNCH phai thuflng xuyen boat dflng va lam viec trong moi truflng het sflc kho khan, nguy hiem nhu: cflu ho tren cao, dufli vuc sau, mfl tim nan nhan duflt nuflc, khu vgc bi rfl rl hfla ehdt, phong xa„. dac biet la trong dieu kign efl khfli, khf dgc thi nhflng tai nan thfl cap co thd xiy ra va nhflng nguy hiem dang rinh rap ho ba't ci} lue nao.
can cfl theo Digu 12 Quyet dinh sfl 44/ QD- H g ngay 15/10/2012 "Quy dinh ve cflng tac CNCH cua lyc lugng PCCC". Co thd phan loai sU co trong dieu kign CO khfli, khf dgc theo cac tinh hufl'ng co bin sau: cfl ngufli bj nan trong SL/ CO chay, no; co ngufli bj nan trong sy co sap do' nha, cflng trinh; co ngufli bj nan trong sy cfl so so hoa chat; co ngufli bi ngn dudi him, hflsSu. trong hang, cong trinh ngam,
Sy cfl trong dieu kien co khoi, khi doc la su viec xiy ra trong qua trinh hoat dong tgi mpt moi truflng nao do cfl nflng dp khoi hay khi doc vugt qua gidi ban cho phep nguy cd gay anh huflng xau den sflc kho6, tfnh mang cua ngufli va tai san, gay hai cho dflng thyc vat va moi triiflng.
Sg cfl trong dieu kign co nhieu khoi khi doc thuflng xay ra 6 nhDng dam chay nha kin. nha nhieu ting, cao ting, nha ham hay ham tau, ngoai ra chay mflt sfl hfla chdt nhU' xang dau. cao su, chay cac chdt hflu CO nhu: spi, len, da, chat deo, polyme.. t6a nhidu khfli den, dflc hai va tugng doi dam dac, gay khfl khan eho viic trinh sat, nhin dinh chfnh xac tinh hlnh. Vi vgy, iam giam nflng do khfli khf dflc tri^c khi tidn hanh eae boat dgng CNCH la vigc lim quan trgng va ein thidt.
Theo Didu 36, Didu Ignh chig'n ddu ciia Igc lugng chila ehay quy djnh: "Khi ehfla chay, ndu xet thdy cdn thidt thi chl huy chfla chiy cho mfl 16 thoat khfli, tao didu kign thuan lgi eho vigc cflu ngufli va chfla ehay. Khi md cua thoit khoi phai chu j han chd ddn mflc thdp nhdt khi ning ehay lan, phit tridn ehiy Ifln
od thoat khfli 9 dam chiy hay tai cic sy cfl co khfli khf dge hgp ly nhdt la mS cic cQa sd, cac cila chidu sang, cUfa trfli. Ndu dign tfch eua eie cQa nay khflng dD dd thoat khfli ta cfl the mfl rflng hdn bing each thao dfl cae cdu kign. Ndu khflng cfl cae Ifl, cfla dd thoit khol trong truflng hgp cin thidt chT huy cho thao dfl eiii kign nhu: tuflng, tran hay mai dd thoat khfli. Vige thao dfl phii tuan theo Oidu 37, 38 va 39 cOa didu l$nh chidn ddu cDa lyc lugng chQa chiy.
Neu thoat khfli bSng dfli luu tu nhifin khflng cfl higu qua thi lyc IUdng CNCH cfl the sfl dyng cac thidt bj chuygn diing nhu quat hut hoie ddy khfli d^
ehflng khfli. Vfli eac phuong tign nay ta cfl thd chflng khfli bang hai bign phap:
Thfl nhdt, dflng quat hiit khol dd hiit khfli ra.
ThiJf hai, diing quat hut khflng khf sach & bgn ngoii thfli vao trong phong dd dly khfli ra ngoai.
_.69 thang 4'2015
