Abacimi-mlilo basebenzisa i-aqueous Film-forming foam (AFFF) ukunceda ukucima imililo enzima ukuyilwa, ingakumbi imililo equka i-petroleum okanye ezinye izinto ezivuthayo ‚ ezaziwa ngokuba yimililo yeClass B. Nangona kunjalo, ayizizo zonke ii-fire foams ezihlelwa njenge-AFFF.

Ezinye iifomyula ze-AFFF ziqulathe udidi lweekhemikhali ezaziwa ngokubaii-perfluorochemicals (ii-PFC)kwaye oku kuphakamise inkxalabo malunga namathuba okubaungcoliseko lwamanzi angaphantsi komhlabaimithombo ekusetyenzisweni kweearhente ze-AFFF eziqulethe ii-PFC.

NgoMeyi 2000,Inkampani ye-3Mithe ayisayi kuphinda ivelise i-flurosurfactants esekelwe kwi-PFOS (perfluorooctanesulphonate) esebenzisa inkqubo ye-fluorination ye-electrochemical. Ngaphambi koku, ii-PFC eziqhelekileyo ezisetyenziswa kwi-foams zokulwa nomlilo yayiyi-PFOS kunye nezinto eziphuma kuyo.

I-AFFF iyicima ngokukhawuleza imililo yamafutha, kodwa ine-PFAS, emele izinto ze-per- kunye ne-polyfluoroalkyl. Olunye ungcoliseko lwe-PFAS luvela ekusebenziseni amagwebu okucima umlilo. (Ifoto/Joint Base San Antonio)

AMANQAKU AFANELEKILEYO

Ukuqwalasela 'indlela entsha eqhelekileyo' yezixhobo zomlilo

Umsinga onetyhefu 'wegwebu eliyimfihlakalo' kufutshane neDetroit wawuyiPFAS - kodwa wawuvela phi?

Igwebu lomlilo elisetyenziselwa uqeqesho eConn. linokubangela iingozi ezinkulu empilweni nakwindalo esingqongileyo

Kwiminyaka embalwa edlulileyo, ishishini le-foam yokulwa nomlilo liye lasuka kwi-PFOS kunye nezinto eziphuma kuyo ngenxa yoxinzelelo lomthetho. Abo bavelisi baye baphuhlisa baze bazisa kwimarike ii-foam zokulwa nomlilo ezingasebenzisi ii-fluorochemicals, oko kukuthi, ezingena-fluorine.

Abavelisi beefoam ezingenafluorine bathi ezi foam azinampembelelo ingako kwindalo esingqongileyo kwaye ziyahlangabezana neemvume zamazwe ngamazwe zeemfuno zokulwa nomlilo kunye nolindelo lwabasebenzisi bokugqibela. Nangona kunjalo, kusekho inkxalabo kwindalo esingqongileyo malunga neefoam zokulwa nomlilo kwaye uphando ngalo mba luyaqhubeka.

UXHALABA NGOKUSENZISWA KWE-ACFF?

Le nkxalabo igxile kwimpembelelo embi enokubakho kwindalo esingqongileyo ngenxa yokukhutshwa kwezisombululo ze-foam (ukudityaniswa kwamanzi kunye ne-foam concentrate). Imicimbi ephambili yityhefu, ukubola kwezinto eziphilayo, ukuqina, ukunyangwa kwezityalo zokucoca amanzi amdaka kunye nomthwalo wezondlo zomhlaba. Zonke ezi zinto zibangela inkxalabo xa izisombululo ze-foam zifikelela.iinkqubo zamanzi zendalo okanye zasekhaya.

Xa i-AFFF equlathe i-PFC isetyenziswa ngokuphindaphindiweyo kwindawo enye ixesha elide, ii-PFC zinokusuka kwi-foam ziye emhlabeni zize zingene emanzini angaphantsi komhlaba. Ubungakanani bee-PFC ezingena emanzini angaphantsi komhlaba buxhomekeke kuhlobo kunye nobungakanani be-AFFF esetyenzisiweyo, apho isetyenzisiwe khona, uhlobo lomhlaba kunye nezinye izinto.

Ukuba kukho imithombo yabucala okanye kawonke-wonke ekufutshane, inokuthi ichaphazeleke yi-PFCs kwindawo apho i-AFFF yayisetyenziswa khona. Nantsi ingqwalasela yoko kupapashwe liSebe lezeMpilo laseMinnesota; lelinye lamazwe aliqela.uvavanyo longcoliseko.

“Ngo-2008-2011, i-Minnesota Pollution Control Agency (MPCA) yavavanya umhlaba, amanzi angaphezulu komhlaba, amanzi angaphantsi komhlaba, kunye nenkunkuma kwiindawo ezili-13 ze-AFFF ezikufutshane neli lizwe. Bafumanise amanqanaba aphezulu e-PFC kwezinye zeendawo, kodwa kwiimeko ezininzi ungcoliseko aluzange luchaphazele indawo enkulu okanye lubeke umngcipheko ebantwini okanye kokusingqongileyo. Iindawo ezintathu - iDuluth Air National Guard Base, iBemidji Airport, kunye neWestern Area Fire Training Academy - zachongwa apho ii-PFC zazisasazeke khona kangangokuba iSebe lezeMpilo laseMinnesota kunye ne-MPCA bagqibe ekubeni bavavanye imithombo yokuhlala ekufutshane.

"Oku kunokwenzeka ngakumbi kufutshane neendawo apho i-AFFF equlathe i-PFC isetyenziswa rhoqo, njengeendawo zoqeqesho lomlilo, izikhululo zeenqwelo-moya, iindawo zokucoca, kunye nezityalo zeekhemikhali. Akwenzeki kakhulu ukuba kwenzeke ngenxa yokusetyenziswa kwe-AFFF kube kanye ukulwa nomlilo, ngaphandle kokuba kusetyenziswa imithamo emikhulu ye-AFFF. Nangona ezinye izicimi-mlilo eziphathekayo zinokusebenzisa i-AFFF equlathe i-PFC, ukusetyenziswa kwemithamo emincinci kangako kube kanye akunakwenzeka ukuba kube yingozi emanzini angaphantsi komhlaba."

UKUKHUTSHWA KWEFOMU

Ukukhupha isisombululo se-foam/samanzi kusenokwenzeka ukuba kungenxa yesinye okanye ngaphezulu kwezi meko zilandelayo:

• Imisebenzi yokucima umlilo ngesandla okanye yokufaka ipetroli;
• Uqeqesho apho kusetyenziswa igwebu kwiimeko ezithile;
• Uvavanyo lwezixhobo zefoam kunye nezithuthi; okanye
• Ukukhululwa kweenkqubo ezilungisiweyo.

Iindawo apho esinye okanye ezingaphezulu kwezi ziganeko zinokuvela khona ziquka izixhobo zeenqwelo-moya kunye nezixhobo zoqeqesho lwabacimi-mlilo. Izixhobo ezikhethekileyo ezinobungozi, ezifana neendawo zokugcina izinto ezinokutsha/ezinobungozi, izixhobo zokugcina ulwelo olunokutsha kakhulu kunye nezixhobo zokugcina inkunkuma enobungozi, nazo zidweliswe kuluhlu.

Kucetyiswa kakhulu ukuqokelela izisombululo ze-foam emva kokuba zisetyenziselwe imisebenzi yokucima umlilo. Ngaphandle kwenxalenye ye-foam ngokwayo, i-foam isenokuba ingcoliswe yi-fuel okanye amafutha abandakanyeka kumlilo. Ngoku kukho isiganeko sezinto eziyingozi rhoqo.

Amaqhinga okulawula ngesandla asetyenziswa xa kuchitheka amanzi anobungozi kufuneka asetyenziswe xa iimeko kunye nabasebenzi bevuma. Oku kuquka ukuvala imisele yamanzi ukuze kuthintelwe ukuba isisombululo segwebu/samanzi esingcolisiweyo singangeni kwinkqubo yamanzi amdaka okanye kwindawo engqongileyo singajongwanga.

Amaqhinga okuzikhusela anjengokugalela amadama, ukugrumba kunye nokujika amanzi angene kwindawo efanelekileyo yokugquma ide isuswe ngumntu ococa izinto eziyingozi.

UQEQESHO NGEFOMBI

Kukho iifoam zoqeqesho ezenzelwe ngokukodwa ezifumaneka kubavelisi abaninzi befoam ezilinganisa i-AFFF ngexesha loqeqesho oluphilayo, kodwa azinazo ii-flourosurfactants ezifana ne-PFC. Ezi foam zoqeqesho zihlala zibola kwaye azinampembelelo ingako kwindalo; zinokuthunyelwa ngokukhuselekileyo kwisityalo sokucoca amanzi amdaka sendawo ukuze zicutshungulwe.

Ukungabikho kwe-flourosurfactants kwi-training foam kuthetha ukuba ezo foam zinokumelana okuncinci nokutsha. Umzekelo, i-training foam iya kubonelela ngomqobo wokuqala womphunga kumlilo wolwelo oluvuthayo obangela ukucima, kodwa loo ngubo yefoam iya konakala ngokukhawuleza.

Yinto entle leyo ngokwembono yomqeqeshi kuba oko kuthetha ukuba ungenza ezinye iimeko zoqeqesho kuba wena nabafundi bakho anilindeli ukuba isixhobo soqeqesho siphinde silungele ukutsha kwakhona.

Imithambo yoqeqesho, ingakumbi leyo isebenzisa igwebu eligqityiweyo, kufuneka ibandakanye amalungiselelo okuqokelelwa kwegwebu elichithiweyo. Ubuncinane, amaziko oqeqesho lomlilo kufuneka abe nakho ukuqokelela isisombululo segwebu esisetyenziswa kwiimeko zoqeqesho lokukhupha amanzi amdaka kwiziko lokucoca amanzi amdaka.

Ngaphambi kokuba kukhutshwe loo nkunkuma, kufuneka kwaziswe indawo yokucoca amanzi amdaka kwaye kunikwe imvume kwicandelo lomlilo yokuba iarhente ikhululwe ngexabiso elimiselweyo.

Ngokuqinisekileyo uphuhliso kwiinkqubo zokungenisa i-foam yeKlasi A (mhlawumbi nekhemistri yearhente) luya kuqhubeka luhambela phambili njengoko belunjalo kwiminyaka elishumi edlulileyo. Kodwa ngokubhekisele kwi-foam concentrates yeKlasi B, imizamo yophuhliso lwekhemistri yearhente ibonakala ngathi iye yamiswa ngexesha ngenxa yokuxhomekeka kwiiteknoloji ezikhoyo.

Kuphela ukusukela oko kwaqaliswa imithetho yokusingqongileyo kwiminyaka elishumi edlulileyo okanye ngaphezulu kwii-AFFF ezisekelwe kwi-fluorine apho abavelisi befoam yokucima umlilo bathathe umngeni wophuhliso nzulu. Ezinye zezi mveliso zingena-fluorine zezesizukulwana sokuqala kwaye ezinye zezesizukulwana sesibini okanye sesithathu.

Ziya kuqhubeka zitshintsha kwi-agent chemistry kunye nokusebenza komlilo ngenjongo yokufezekisa ukusebenza okuphezulu kulwelo oluvuthayo nolutshayo, ukuphucula ukumelana nokutsha kokhuseleko lwabacimi-mlilo kunye nokubonelela ngeminyaka emininzi eyongezelelweyo yobomi phezu kwamagwebu avela kwiproteni.