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Puhi Puhi, Pahu Uila Malalo o ka Honua, a me na Nahaha o ka Paipu mahu

He ʻokoʻa nā helu ulia pōpilikia ma ka ʻāina. Hoʻohana kēia ʻaoʻao i ka 911, ka helu no ʻAmelika a me Kanada. Nui nā ʻāina ʻē aʻe i hoʻohana i ka 112, 999, a i ʻole ka helu ʻē aʻe. E huli i ka helu no kou ʻāina.

Ma lalo o nā ala kaʻa kaʻa a me nā alanui asphalt o nā kūlanakauhale nui e holo ana ka labyrinth o nā mea hānai uila nui a me ka lua, nā mea hoʻololi hoʻoili ʻaila piha i ka mineral, nā kumu kinoea maoli i kaomi ʻia, nā ʻauwaʻa kelepona, a me nā paipu mokumahu ʻāpana wela. Ke hoʻoheheʻe ʻia ka paʻakai o ke alanui i ka hoʻoilo a i ʻole ke kau wela nui o ke kauwela e hoʻoheheʻe ʻia ka uwea uila ma lalo o ka honua i ka char a pyrolyze, a i ʻole i ka wā e pā ai ka wai ma lalo o ka ʻāina i kahi mokuahi moku nui, hiki i ka ʻili o ke alanui ke hoʻololi i kahi pōhā make i kekona. Hiki ke pahū me ka ikaika e hoʻokuʻu i kahi pahu pahu hao he 135 kilo (300 paona) he 15 a 45 mika (50 a 150 kapuaʻi) i ka lewa i ka wā e pana ana i ka ipukukui kalapona a me ke kinoea e puhi ana ma lalo o ka poloka.

Pēia nō hoʻi, ua hū ʻia kahi ** mokumahu nui o ka hāmare wai nui** ma ke ʻano he geyser kiʻekiʻe kiʻekiʻe o 175-a-200-degere-Celsius (350-a-400-degree-Fahrenheit) mahu, ka lepo paila, a me ka hoʻoilina hoʻoilina ** insulation paipu asbestos**. ʻIke i ka ʻike ʻana i ka ʻike ʻana i ka mahu hoʻoilo hoʻoilo maikaʻi ʻole mai ka pahū ʻana i lalo o ka honua a i ʻole ka haki ʻana o ka mahu kiʻekiʻe, pehea e neʻe ai ma waena o ke kahua pulu ikaika me ka loaʻa ʻole o ka make ** ʻāhewa-voltage electrocution**, a pehea e hoʻopaʻa ai i kou keʻena me ka lalo o ka honua **carbon monoxide (CO) e mālama i kou ola a me kou ʻohana.

E hana i kēia i kēia manawa

  1. E neʻe ma kahi o 50 a 100 mau mika (165 a 330 kapuaʻi) i uka a piʻi i luna mai ka puka puhi, ʻā a i ʻole ka ʻūhā ʻana i ka manawa koke. Mai hele wāwae, kū kokoke, a i ʻole e hoʻokuʻu i ke kiʻi ʻana i ka uhi puka a i ʻole ka pahu alahele e hoʻoheheʻe ana i ka uahi ʻeleʻele, ke kinoea ʻeleʻele melemele, nā ʻālohilohi, a i ʻole ka pahu mahu. Hiki i nā uhi hao paʻa 135-kilogram (300-pauna) ke pahū me ka ʻike ʻole ʻia, a hiki i ka asphalt ma luna o kahi holoi mahu ke hāʻule i loko o kahi lua e hoʻolapalapa ai ma lalo o kou mau wāwae.
  2. Mai hehi i na pahu metala, uhi manhole, pahu pono, kia alumina alanui kukui, a pulu pulu paha. I ka wa o na uwea o lalo o ka honua a me ka hooilo o ka paakai o ke alanui, hooheheeia na laina lua e hoohehee pinepine i na po'i hao hao, na pahu kupapau alanui, na kumu kukui metala, a me 40 kaulahao kaulahao, a me 40 kaula kaulahao. volts AC**. E mālama pono i nā keiki a me nā ʻīlio i hoʻopaʻa ʻia ma luna o ke kaʻa waena maloʻo mai nā metala alanui āpau.
  3. Kele koke i kāu helu ulia pōpilikia mai kahi mamao palekana. Kāhea iā 911 ma ʻAmelika Hui Pū ʻIa a me Kanada, 112 ma waena o ʻEulopa, 999 ma United Kingdom, a i ʻole e nānā i kā mākou helu pilikia papa kuhikuhi. E hōʻike i ke ala pololei, ka waihoʻoluʻu a me ke ʻano o ka uahi a i ʻole ka mahu, a inā paha aia nā lapalapa, nā leo popping, a i ʻole kahi uhi manhole haʻalulu.
  4. **E hoʻokuʻu koke i kou hale lalo a i ʻole ke keʻena i lalo inā kani kou ʻūhā CO a i ʻole ke komo ʻana o ka uahi uila ma loko o nā paia i ka wā o ke ahi o ke ala. poloka.
  5. **Inā loaʻa i loko o ka mokuahi mokuahi ʻāpana wela, e hoʻomaha i kou hanu, e uhi i kou waha a me ka ihu me ka lole pulu a maloʻo paha, a e hele mālie i ka makani ma waho o ke ao. Ma hope o ka wehe ʻana i ka ʻāpana mahu, e wehe i nā lole waho i uhi ʻia i ka lepo hina a i ʻole ka lepo fibrous i ʻole ʻoe e hanu i ka chrysotile asbestos mai ka lohi ʻana o ka paipu mahu ma lalo o ka honua.
  6. **Inā ʻike ʻoe i ka ʻuʻu ʻana a i ʻole ka ʻūhā ʻana ma kou mau wāwae a i ʻole nā ​​wāwae ma kahi kokoke i kahi papa hana pulu, e hoʻokuʻu a lele paha me nā wāwae ʻelua e paʻa paʻa. E hoʻopaʻa i kou mau wāwae i ʻole ʻoe e hoʻopaʻa i ʻelua mau apo uila like ʻole (step potential).

Danger

** ʻO nā ʻīlio hele ma nā ʻaoʻao pulu o ke kūlanakauhale ka helu ʻekahi i loaʻa i ka "Stray Voltage" (Contact Voltage) i ka uila, a ʻo ka poʻe nona nā mea nona ka uila e hoʻāʻo nei e huki i kahi ʻīlio hoʻomāinoino mai kahi pā wela. he kumu manhole ikaika a i ʻole ke kumu kukui alanui a me ka ʻōpala pulu. Inā uē koke kāu ʻīlio, maloʻo, a hāʻule paha ma kahi ʻaoʻao pulu a i ʻole ka pahu metala i ka wā hoʻoilo hoʻoilo a i ʻole kahi pilikia manhole, ** MAI hopu i ke kola metala o ka ʻīlio, ka hulu pulu, a i ʻole ke kaula pulu me kou mau lima ʻole**. Huki manuahi i ka ʻīlio me ka hoʻohana ʻana i ka nailona maloʻo a i ʻole ka ʻili ʻili i hoʻopaʻa ʻia a puni ka ʻīlio, a i ʻole ke kīkēkē ʻana i ka ʻīlio mai ka pā metala me ka hoʻohana ʻana i kahi lāʻau pulumu lāʻau maloʻo, moena lāʻau, a i ʻole ke kapa maloʻo i pelu ʻia.

Ka Papa Hoʻoholo Hoʻoholo Rapid: Harmless Vapor vs. Manhole Fire vs. Steam Rupture

Ma nā kūlanakauhale me nā ala hoʻohana ma lalo o ka honua, ʻo ka ʻike ʻana i ka mahu keʻokeʻo e piʻi aʻe ana mai kahi pā alanui i ke kakahiaka hau hau. E hoʻohana i kēia palapala hoʻāʻo ʻike a me ka loiloi e ʻike ai i ka wā i komo ai kahi puka makani i loko o kahi pilikia e hoʻoweliweli i ke ola.

flowchart TD
    A["ʻIke ʻia ka uahi, ka mahu, a i ʻole ka walaʻau e hele mai ana mai ke alanui Manhole a i ʻole ka ʻaoʻao alanui"] --> B{"E nānā i ke kala, ʻala, ka wikiwiki, a me ke kani"}
    B -->|"ʻO ka noe keʻokeʻo ʻōniʻoniʻo, lohi, ʻaʻohe ʻono e ʻauwana palaualelo i ke anuanu"| C["BENIGN VAPOR PLUME: Ka wai lepo a i ʻole ka ua e hahau ana i ka pahu mahu ma lalo o ka honua"]
    C --> D["Hana: E pale i ka he'e 'ana ma luna o ka uhi metala pulu (maka'ala ala uila), 'a'ole pono e ha'alele"]
    B -->|"ʻO ka uahi ʻeleʻele mānoanoa, hina, a melemele ʻulaʻula paha; ʻala ʻaʻa ahi/tar; popping a humming paha"| E["UNDERGROUND ELECTRICAL VULT FIRE / PYROLYSIS: Pahu CO a me H2 hale kinoea i loko o ka auwai."]
    E --> F["Hana: Hoʻomaʻemaʻe koke i ka radius 50m (165 ft); hiki i ka uhi ke hoʻokuʻu i 30m kiʻekiʻe; e nānā i nā hale pili no CO"]
    B -->|"Ka leo o ka jet-engine kuli; kolamu kiʻekiʻe kiʻekiʻe o ka mahu keʻokeʻo / lepo; ʻiliʻili lele"| G["MAHELE O KA APANA HIGH-PRESSURE: 175C a hiki i 200C ka mahu pumehana + hiki ke haule ka lepo asbestos."]
    G --> H["Hana: E haʻalele i 100m+ i ka makani; pale aku i ke ao wili haʻahaʻa; ʻeke lole i uhi ʻia i ka lepo (asbestos protocol)"]
    B -->|"ʻO ka uhi ʻana o ka manhole e ʻakaʻaka ana, hāpai ʻia, a i ʻole ke kīkī ʻana me ka ʻala hua manu popopo (mercaptan) a i ʻole ke kinoea hili."| I["KA HOʻOPIʻI KĀMAʻI KULA: Leak kinoea maoli a i ʻole ka methane i loko o ke kahawai lalo"]
    I --> J["Hana: E haʻalele koke i ka poloka; Mai hoʻomaka i nā ʻenekini kaʻa a hoʻohana paha i nā hoʻololi kokoke; kelepona i ka helu pilikia"]

Mahele 1: Puhi Puhi Puhi a me nā Pahū Uila Ma lalo o ka Honua

No ke aha e pahū koke mai ai e like me ka pūkuniahi ka uhi ʻana o ka pahu hao nui e noho ana ma luna o ke kaʻa paʻa? ʻO ka hoʻomaopopo ʻana i ke kemika o lalo o ka ** cable insulation pyrolysis** e wehewehe i ke kumu o ka manhole "e puhi māmā wale ana" i kona wā pahū.

1. Ka physics o ka huki alanui-paakai a me ka insulation pyrolysis

I loko o nā kikowaena kūlanakauhale paʻa, nā kaula uila kiʻekiʻe-voltage (maʻamau 4,160V a hiki i 34,500V) a me nā kiʻina haʻahaʻa haʻahaʻa haʻahaʻa haʻahaʻa haʻahaʻa kiʻekiʻe (120/208V a i ʻole 277/480V ma ʻAmelika ʻĀkau; 230/400V ma ʻEulopa a me UK) e holo ana ma lalo o ka lepo a i ʻole ka pāpaʻi paʻa paʻa paʻa PVC. 30 a 90 mika (100 a 300 kapuaʻi).

ʻElua mau mea hoʻoulu wā e hoʻomaka i ka hapa nui o nā ahi o lalo o ka honua: - Winter and Early Spring Road-Salt Slush: De-icing paʻakai (sodium chloride a calcium chloride) holoi ʻia i loko o nā manhole me ka hoʻoheheʻe ʻana i ka hau e hana i kahi brine electrolyte. Ke komo kēia wai paʻakai i loko o nā māwae liʻiliʻi i loko o ka ʻōpala synthetic kahiko, ka polyethylene (XLPE), a i ʻole nā ​​uwea i uhi ʻia i ke kēpau (PILC) i uhi ʻia i ka pepa, e hoʻokuʻu ʻia nā arc uila ma waena o ka insulation. - Nā Haʻahaʻa Ea Hoʻoluʻu Puʻupuʻu Kau wela: I ka wā lōʻihi o ka wela o ke kauwela, lawe nā kaula lua lalo i ka amperage kiʻekiʻe i ka wā i hoʻopuni ʻia e ka lepo i hoʻomoʻa ʻia e ka lā ʻaʻole hiki ke hoʻopau i ka wela, e kuke ana i nā lole uwea ma mua o 250 a 400 degere Celsius (482 a 752 degere Fahrenheit).

I ka manawa e hoʻomaka ai ke kīʻaha uila e hoʻomoʻa i ka insulation polymer i loko o kahi ʻawaʻawa ma lalo o ka honua pōloli me ka oxygen, ʻaʻole e ʻā maʻemaʻe ka pahu a me ka plastic; akā, e hana ana lākou i ka thermal pyrolysis (destructive distillation), e hana ana i ka ʻea ʻea kinoea hiki ʻole ke ʻike ʻia. - Carbon Monoxide (\(\text{CO}\)): He mea make make a me ke kinoea pahū pahū (nā palena pahū ma waena o 12.5 pakeneka a me 74 pakeneka o ka lewa). - Hydrogen Gas (\(\text{H}_2\)), Methane (\(\text{CH}_4\)), Ethylene (\(\text{C}_2\text{H}_4\)), a me Acetylene (\(\text{C}_2\text{H}_2\)): Hana ʻia e ka māhā wela o ka polyethylene, EPR rubber, a me dielectric transformer mineral aila. ʻO ka hydrogen a me ka acetylene ka laulā ākea loa a hiki ke hoʻā ʻia mai ka liʻiliʻi liʻiliʻi.

2. ʻO ka "Backdraft" Vault Detonation Mechanism

Ke hoʻopiha nei nā kinoea pyrolysis i ke keʻena manhole i hoʻopaʻa ʻia ma lalo o ka honua (ʻo ia ka mea e paʻa ai 4 a 15 cubic mika / 150 a 500 cubic kapuaʻi o ka leo), ʻelua mau mea hiki ke hiki: 1. The Smoldering Rich Phase: I ka hoʻomaka ʻana, hiki i ka manhole ke hoʻokuke i waho i nā ʻūhū palaualelo o ka uahi melemele-hina, ʻeleʻele, a ʻeleʻele paha e pilau e like me ka Bakelite kuni, nā kaʻa puhi, a i ʻole ke kā wela. Inā ʻoi aku ka waiwai o ke kinoea i loko o ka waihona no ka manawa * nui loa * (ʻaʻole lawa ka oxygen), ke kali nei ʻo ia e like me ka poma mua. 2. Ka Hoʻomaka ʻana o ka ʻAha: Ke hoʻoheheʻe ʻia ke kinoea e ka wela i waho o nā puka koho o ka poʻi manhole a ʻo ka ea hou o waho e omo i lalo i kahi awāwa pili, ʻo ka lākiō wahie-a-ea i loko o ka vault i loko o ka stoichiometric explosive range. ʻO ke arc uila e hiki mai ana ma ke uwea poino e hoʻā koke i ka ʻeke kinoea. 3. Pahū Pahū: Piʻi ka piʻi ʻana o loko o ka pahu pahu i nā haneli kilopascals i nā milliseconds. Ua puhi ʻia kahi uhi puka hao paʻa ʻo 90 a i 160 kilokani (200 a 350 paona) i ka lani e like me ka pōʻai pōʻai, wāwahi ʻia nā pale makani, ʻeha nā hale, a pepehi paha i ka poʻe hele wāwae i hoʻokahi poloka, a ukali koke ʻia e kahi pou ahi e kani ana 3 a 10 mika (10 a 33 mau kapuaʻi) mai ka 33 kapuaʻi.

3. ʻO ka mea pepehi huna i loko o nā hale e pili ana: Subterranean Carbon Monoxide (\(\text{CO}\)) migration

ʻOiai inā ʻaʻole e pahū ka puka puhi puhi ma ke alanui ** ʻaʻole loa ia e pahū**, he mea hoʻoweliweli koke ia no ka make nui ʻana i ka poʻe e hiamoe ana a hana paha i loko o nā hale ma ka poloka holoʻokoʻa.

  • Holo pololei nā ʻauwaʻa uila ma lalo o ka honua, nā ʻauwaʻa telecom fiber, a me nā lima lima kinoea/wai kahiko mai ka pahu manhole alanui ma o ka paia kumu i loko o nā keʻena pono o lalo o nā hale, nā hale ʻai, a me nā hale hale.
  • I ka wā e ʻā ana ke kaula i loko o ka puka alanui i pani ʻia, ʻo ka hoʻonui ʻana i ka wela a me ke kaomi kinoea i kūkulu ʻia i loko o ka manhole ** hoʻoikaika i ka Carbon Monoxide (\(\text{CO}\)), ʻoi aku ma mua o 2,000 a 10,000 mau ʻāpana o ka miliona (ppm), ma ka ʻaoʻao ma o kēlā mau auwai uwea lalo pololei i loko o nā hale lalo.**
  • Ma muli o ka kānana pinepine ʻana o nā ʻāpana ʻāhiʻu i ka lepo a me nā mea e hoʻopaʻa ai i ke ala ma ke ala, ** hiki i ke kinoea carbon monoxide ke kahe ʻana i ka basement a piʻi i luna i nā alapiʻi a me nā ala ʻeleʻele ma mua o ka honi ʻana o ka poʻe noho i ka uahi.**
  • Ka hana i loko o ka hale i ka wā o ke ahi o ke alanui: Inā loaʻa kahi pahu puhi a ʻā paha ma nā wahi a pau o kāu poloka, e nānā koke i kou home ** Carbon Monoxide detector**, e haʻalele i ka papa lalo a me ka papahele o lalo, e wehe i nā puka makani ma ka ʻaoʻao o ka hale e kū pono ana * mai ka uwahi o ke alanui, a e hoʻokuʻu loa i ka hale inā honi ʻoe i ka ʻeha o ka hale, a i ʻole ke poʻo o ke poʻo. nausea. E ʻike i kā mākou kalapona monoxide a me ka uahi inhalation kōkua mua alakai.

Papa Hoʻohālikelike Diagnostic: Nā mea hoʻohana ulia pōpilikia ma lalo o ke alanui

ʻAno pōʻino alanui Plume a me ke kala Pulima Aala & Leo ʻO nā pōʻino make mua Ka lōʻihi palekana palekana
** Leak mahu ʻino ʻole** (Condensation / Weeper) ʻO ka noe keʻokeʻo lahilahi, ʻeleʻele, ʻeleʻele mālie i ka wikiwiki haʻahaʻa; nalo koke aku i kahi mika ma luna o ka pā ʻAʻala ʻole (a i ʻole honi wai mineral mehana); ʻoluʻolu a mālie paha Poʻi metala wela pulu (hiki ke puhi i nā wāwae wāwae ʻole/ʻili ma 60°C a i 90°C) a me ka hoʻoilo hiki ke hoʻoilo ʻia ** ka uila uila** 3 mika (10 kapuai); mai ʻae i nā keiki a me nā holoholona e hele pololei ma ka uhi metala
Uhi / Puhi Uila Manhole (Cable Pyrolysis) ʻEleʻele mānoanoa, ʻeleʻele, a i ʻole ** uahi melemele-ʻeleʻele** e ʻū ana mai nā puka ʻohi uhi; ʻālohilohi polū/keʻokeʻo ma lalo o ka ʻuala ʻOiʻi, ʻāʻī ** ʻāpalapala ʻaʻa, kākā wela, a i ʻole ʻala hoʻopololei uila**; kani leo nui 50/60 Hz, popping, a i ʻole nā pana pū 135 kg (300 paona) pahū uhi manhole e lele ana, pahu puhi puhi ahi, ke uila uila hele hewa, a me ka poison CO i loko 50 a 100 mika (165 a 330 kapuaʻi) i ka makani; e haʻalele koke i nā basements pili
**Pahū ʻAila Hoʻopiha ʻia i loko o ka ʻAila ʻO ka pōʻai ahi nui a ukali ʻia e nā moʻolelo kiʻekiʻe ʻAla ʻaila kola ʻaʻa nui (a me ** polychlorinated biphenyl / PCB** soot i nā ʻāpana hoʻoilina mua o ka makahiki 1980) ʻO ka nalu pahū, nā puka ala hele kila lele, ka ʻaila ʻaila transformer paila, a me ka hoʻohu ʻana i ka ʻona PCB/dioxin ʻona. 100+ mika (330+ kapuaʻi) i ka makani; pani hale HVAC ea hou
Haka Mokumahu Nui o ka Apana Pumi Kiekie (Pahu Hammer Wai) Kiʻekiʻe kiʻekiʻe 30-a-90-mika (100-300-kapuai) geyser o ka mahu keʻokeʻo paʻapū i hui pū ʻia me ka lepo ʻeleʻele/hinahina, nā ʻāpana asphalt, a me nā pōhaku. Kaʻahi kaʻa ukana / jet-engine leo (100 a 125 decibels); ʻike ʻia ka haʻalulu honua ma nā kapuaʻi kāmaʻa Mai koke i ka 175°C a 200°C (350°F a 400°F) ka wela wela, asphyxiation, e paila ana i na ana alanui, a me ka lewa asbestos ea 100 a 150 mika (330 a 500 kapuaʻi) i ka makani a me ka piʻi (hōʻalo i ka hoʻoheheʻe ʻana o ka wai ma nā ʻauwai)
** Leak kinoea maoli i loko o ka manhole** ʻO nā puna wai ma ke alanui, ka lepo e puhi ana i luna, a i ʻole ** uhi manhole i ka hula/kaʻakaʻaka** me ka ʻeleʻele. Ikaika rotten-egg / skunk odor (mercaptan); kani kiʻekiʻe a uwē paha ma lalo o ka honua Pahū poʻokela poʻokela inā hoʻā ʻia e kekahi kaʻa, ʻōlinolino a i ʻole kelepona paʻalima 100+ mika (330+ kapuaʻi) i ka makani; ike nahae ka paipu kinoea

Mahele 2: Pahū ʻApana Mokumahu a me ka hāʻule ʻana o Asbestos

Ma nā wahi metropolitan nui (e like me New York City, Paris, Berlin, Copenhagen, Boston, Philadelphia, Denver, Warsaw, Seoul, a me Beijing), ʻaʻole loaʻa nā hale kiaʻi kalepa, nā halemai, a me nā hale paʻa i kā lākou mau paila haʻahaʻa. Akā, e loaʻa iā lākou ** ʻahi mokuahi superheated kiʻekiʻe ** i puhi ʻia ma lalo o ka honua mai nā mea kanu cogeneration waena ma o ka hao hao a i ʻole welded carbon-steel mains e hana ana ma 1,000 a 2,800 kilopascals (150 a 400 psi) a me nā mahana ma waena o **175 a me 230 degere Celsius (350 Fah.

1. Pehea ka ua ʻino e hoʻoulu ai i kahi pahū "Condensation Water Hammer".

Pehea e hiki ai i ka ua nui a i ʻole ke kahe wai nui ma waho o kahi paipu mahu kila mānoanoa e pahū ai ka paipu me he mea lā? He ʻano thermodynamic ka mea hewa i kapa ʻia ʻo Condensation-Induced Water Hammer (CIWH):

  1. ʻO ka maʻamau, hele ka mahu puʻe kiʻekiʻe ma lalo o ke kila kila ma ke ʻano he kinoea maloʻo a wela loa i ka wikiwiki o 80 a 150 kilomita i ka hola (50 a 95 mph), ʻoiai e kahe ana ka wai liʻiliʻi o ka wai i hoʻopaʻa ʻia ma o ka mīkini ma ke alanui ** mau pahele mahu**.
  2. Inā kahe ka ua nui i ka lua o lalo o ka ʻāina ma mua o ka hiki ke hoʻomaʻemaʻe ʻia, a i ʻole ka pohā o ka wai anuanu e pili ana i ka wai anuanu ma waho o ka paipu mahu, maʻalili koke ka paipu kila a hoʻomālili i ka mahu i loko.
  3. I loko o nā minuke, e hoʻokuʻu hou ana nā haneli lita o ka mahu i loko o ka paipu i loko o ka wai hoʻolapalapa wai e hōʻiliʻili ana i lalo o ka paipu a ke hoʻomau nei ka mahu kiʻekiʻe i ka heihei ma luna o ka nalu wai.
  4. ʻO ka mahu e hahau ana i ka wai wai i loko o ka paipu i loko o ka paʻa wai paila. Hoʻoulu ʻia e 1,400 kilopascals (200 psi) o ke kaomi mahu ma hope o ia, ʻo ka slug nui-ton o ka wai paila e hoʻolalelale i lalo o ka paipu ma ** ma kahi o 100 mau kilomita i kēlā me kēia hola ** a hoʻopaʻa i ka kuʻekuʻe 90-degere paipu hao a i ʻole ka pahu e like me ka mea hao kila paʻa.
  5. Nahaha koke ka flange paipu a i ʻole ka pā hao. No ka mea, ua wela loa ka wai o loko o ka paipu ma luna o 100 degere Celsius (212 degere Fahrenheit) ma lalo o ke kaomi ʻana, i ka manawa e wehe ai ka paipu i ke kaomi o ka lewa, e ʻā ana ka wai wela loa i mahu, e hoʻonui ana i 1,600 manawa i ka leo ma kahi hapa o kekona.
  6. ʻO kēia BLEVE (Boiling Liquid Expanding Vapor Explosion) ke puhi nei i ka lua 6 a 15 mika (20 a 50 kapuaʻi) ākea ma o ke alanui paʻa paʻa, ke kiola ʻana i nā kaʻa, nā pōhaku asphalt, a me nā moʻolelo lepo hū i ka lewa.

2. Ke ola nei i ka pohā o ka mahu ma ke alanui a i ʻole ma ke kaʻa

Inā naha ka mokuahi lalo ma kahi kokoke iā ʻoe:

  • Mai hanu pono i ka mahu ola (Preventing Thermal Airway Edema): ʻAʻole e like me ka ea wela maloʻo i loko o ka sauna, **ʻoi aku ka nui o ka ikehu wela ma ka leo 4,000 mau manawa ** a hoʻokuʻu i ka nui o ka latent heat of condensation i ka manawa e pā ai i nā mucous membrane mau o kou puʻu a me nā kaula leo. Hiki i ka hanu hohonu hoʻokahi o ka mahu wela loa ke hoʻohūhū i ka epiglottis a me ka larynx, e hoʻoulu ai i ka pehu wikiwiki (laryngeal edema) e hoʻopaʻa ai i ka paipu makani i loko o 15 a 30 mau minuke. E hoʻopaʻa koke i kou hanu, e kaomi i ka pālule i pelu ʻia, ka ʻaʻahu, a i ʻole ka lole pulu ma luna o kou ihu a me kou waha, e noho haʻahaʻa (piʻi koke ka mahu), a neʻe i ka makani a pololei i ka hulu.
  • E noho ma waho o nā ʻauwai alanui a pale aku i ka ʻalapalapala palupalu: Hoʻolei ka mokuahi pohā i mau tausani lita o 95-a-100-degere-Celsius (203-a-212-degree-Fahrenheit) wai paila i loko o nā ʻauwai alanui a e ʻānai ana i ka lepo ma lalo o nā ala ala a puni. E piʻi ma luna o nā kiʻi hale paʻa a i ʻole kahi maloʻo kiʻekiʻe; Mai komo i ka wai kahe o ke alanui ma kahi kokoke i ka mokuahi, a e hoʻi maikaʻi i hope mai ka lihi o ka lua, e hoʻomau i ke ana i ka wā e holoi ʻia ai ka lepo lalo.
  • Inā paʻa i loko o ke kaʻa kokoke i ka lua mahu: Noho i loko o ke kaʻa me ka ʻōwili ʻia o nā pukaaniani a pau a ua hoʻololi ʻia ka ʻōnaehana HVAC i OFF / Recirculate WALE nō inā aia ke kaʻa ma kahi mamao palekana kahi i haki ʻole ai ke aniani mai nā ʻōpala lele a paʻa ke kahua ma lalo o nā huila. Inā kū pololei ke kaʻa i loko o ka pahu mahu e ʻā ana i kahi e pohā ai ke aniani o ka hale a i ʻole e paila ana ka wai a puni nā puka, e nānā i ka ʻaoʻao o ke kaʻa e piʻi i ka makani o ka geyser, e wahī i kou poʻo a me nā lima i ka ʻaʻahu a i ʻole ka moena papahele kaʻa, a puka i waho ma kahi o ka lua.

3. ʻO ka Asbestos Mud Protocol (Decontaminating after a steam blast)

Ua uhi ʻia ka nui o nā kumu mahu kumulāʻau ma lalo o ka honua ma mua o ka makahiki 1980 i loko o ka insulation thermal mānoanoa me ka chrysotile a amosite asbestos (a i ʻole ka hulu hipa mineral i hui pū ʻia me ka sima asbestos hoʻoilina). I ka wā e pahū ai ka mokuahi, ua puhi ʻia kēlā paipu ma lalo o ka lepo i loko o nā miliona o nā fiber microscopic i hui pū ʻia i loko o ka lepo ʻeleʻele hina/ʻeleʻele a me ka lepo e ua i lalo ma luna o nā poloka a puni, nā kaʻa, a me nā mea hele wāwae.

  • ** ʻOiai pulu ka ʻōpala, paʻa nā ʻili asbestos i loko o ka wai a he haʻahaʻa haʻahaʻa loa ka pilikia.** Hoʻomaka ka pōʻino inhalation nui 30 a 60 mau minuke ma hope o ka maloʻo ʻana o ka lepo hina i ka lepo maikaʻi ma kou ʻaʻahu, lauoho, kāmaʻa, a me ka ʻili a lilo i ka lewa.
  • E hāhai i kēia 4-Step Asbestos Decontamination Protocol ma hope koke o ka pakele ʻana i ka wahi pahū:
    1. Mai kāhili, lulu, a hoʻomaʻemaʻe paha i ka lepo hina maloʻo mai kou ʻaʻahu. ʻO ka pulupulu ʻana i ka lepo maloʻo e hana i kahi ao paʻa o nā fiber asbestos respirable i mua pono o kou alo.
    2. E hoʻomaʻemaʻe a pulu i kou lole waho ma mua o ka wehe ʻana: Ma mua o kou komo ʻana i ka hale a i ʻole kaʻa maʻemaʻe, e kāpīpī mālie i kou ʻaʻahu i uhi ʻia i ka lepo, ka pālule, a me nā kāmaʻa me ka wai i hiki ʻole ai ka lepo ke lele i ka ea, a laila ** ʻili i nā lole i waho a i waho** (huki makaʻala i nā pālule ma luna o ke poʻo me ka pani ʻana i nā maka a me ka waha, a i ʻole e ʻoki ʻia me ka ʻokiʻoki).
    3. ** ʻAʻahu a me nā kāmaʻa i haumia ʻelua ʻeke:** E sila i nā lole i pāpaʻi ʻia i ka lepo, nā ʻeke ʻeke, a me nā kāmaʻa i loko ʻelua ʻeke ʻōpala paʻa kaumaha i hōʻailona maopopo ʻia no ka hoʻolei ʻia ʻana o nā mea pōʻino e nā mea pane kaiapuni o ke kūlanakauhale. Mai hoʻokomo i nā lole i hoʻohaumia ʻia e ka asbestos i loko o ka mīkini holoi hale a i ʻole ka mea maloʻo, kahi e hoʻohaumia mau ai i ka mea hana a me kāu holoi lole e hiki mai ana.
    4. E holoi pono me ka wai mehana a me ke kopa maʻemaʻe: Holoi i kou lauoho, ka maka, a me ke kino ma lalo o ka wai kahe (holoi mai ke poʻo a ka wāwae i ʻole e kahe ka wai lepo i kou mau maka). Inā ʻoe i loko o kahi hale kokoke i ka pahū, ** e hoʻopau koke i nā ea makani puka makani a me nā mea pā HVAC waena** a hoʻopaʻa i nā puka makani me ka lipine i ʻole e omo ʻia ka lepo o waho i kāu hana.

Mahele 3: "Stray Voltage" (Contact Voltage) ma nā alanui alanui ʻo Wet City

ʻOiai ʻaʻohe manhole e puhi ana a pahū paha, ʻo nā uwea lua o lalo o lalo o ka honua i haki ʻia e ka paʻakai hoʻoilo a i ʻole ka ʻeli ʻana e kahe pinepine 60 a 480 volts o ke au ʻauʻau i loko o ka lepo pulu a me nā mea paʻa alanui hao a alumini paha. Ua kapa ʻia kēia e nā mea hoʻohana ʻo Contact Voltage a i ʻole Stray Voltage.

ʻAʻole hiki ke pale ʻia nā ʻili o ke kaona nui i ka wā ua, hoʻoheheʻe hau, a i ʻole ka manhole

Paku Alanui Kaona No ke aha e lilo ai i mea hoʻoikaika uila Palekana Pedestrian & Pet Rula
Ka Uʻi Hoʻoheheʻe Haʻa-Iron a me nā Paʻa Paʻa Paʻa Paʻa Paʻa Paʻa ʻaoʻao Noho pololei ma luna o nā splices lua; kulu ʻia ka ʻōpala paʻakai ma luna o nā kaula 120V/208V/480V i hakihaki ʻia a i ʻole e kau pololei ke kaula i ke kiʻi hao. Mai hele wāwae ma luna o nā uhi metala a i ʻole nā ​​kuki, ʻoi aku ma nā kāmaʻa pulu a me kahi ʻīlio; e kaʻapuni loa ma luna o ke kaʻa maloʻo
Nā pou kukui alanui metala, nā pahu hōʻailona kaʻa, a me nā hale kaʻaahi i hoʻomālamalama ʻia Hānai ʻia e nā uwea kukui alanui 120V/277V/480V i kanu ʻia ma ke alanui nona ka insulation e hoʻopau pinepine i kahi e komo ai ka uea i ke kumu metala. Mai hilinaʻi i ka pou kukui alanui metala a ʻae paha i ka ʻīlio e mimi a i ʻole e honi i kahi kumu kia metala (ke kahe ʻana o ka mimi i ke au make)
Scaffolding Sidewalk Construction, Nā Pā Paʻa Metala, a me nā Pa Hoʻopaʻa Hoʻopaʻa Paʻa ʻO nā pā metala no ka manawa i waiho ʻia ma luna o nā ʻauwaha hoʻohana hāmama a i ʻole ka scaffolding i hoʻopaʻa ʻia ma luna o nā pahu pahu i hoʻoikaika ʻia e hana i nā hewa ma kahi poloka holoʻokoʻa. E ʻaʻa i ke alanui ma mua o ka hele wāwae ʻana ma nā ʻauwaha kila pulu i ka wā o ke pio uila a i ʻole ka hanana kukui alanui

Pehea e hoʻopakele ai i ke kanaka a i ʻole ka holoholona i haʻalulu i ka uila hele hewa

  1. E ʻike i ke ʻano ma mua o ka hoʻopā ʻana i ka mea i hoʻopā ʻia: Inā hāʻule kekahi i ka hoʻopā ʻana i ke kukui metala alanui, ke kahua kaʻa kaʻa, ka pā, a i ʻole ka uhi ʻana o ka manhole pulu, a i ʻole ka ʻīlio e uwē ana, e pio i kona kua, a hāʻule ma kahi ʻaoʻao pulu, e manaʻo ʻoe e ola ana ka lepo a me ka mea metala ma 120 a 480 volts.
  2. E mālama i kou mau wāwae ma ke kaʻa maloʻo ma kahi mamao aku o ka mea metala. Mai hehi me hoʻokahi kapuaʻi ma ka papahele maloʻo a me hoʻokahi kapuaʻi ma luna o ka paʻu wai a i ʻole ka puddle.
  3. E hoʻokaʻawale i ka pilina me ka hoʻohana ʻana i kahi insulator non-conductive: E hoʻohana i ka lei ʻīlio nailona maloʻo, kahi papa lāʻau maloʻo, kahi pulumu plastik, kahi moena papahele kaʻa, a i ʻole kahi kapa maloʻo mānoanoa i hoʻopaʻa ʻia a puni ka lālā o ka mea i pepehi ʻia e huki iā lākou i 2 mika (6 kapuaʻi) hoʻi i ka lāʻau maloʻo.
  4. E hoʻomaka koke i ka CPR inā ʻaʻole i pane ke kanaka (a i ʻole holoholona) a ʻaʻole hanu: ʻO ke ala ʻokoʻa haʻahaʻa haʻahaʻa (50/60 Hz) e hele ana i loko o ka umauma e hoʻoulu pinepine i ** fibrillation ventricular (hopu puʻuwai)** me ka waiho ʻole ʻana i kahi wela o ka ʻili. E kāhea koke i kāu helu pilikia kūloko, e hoʻomaka i ka hoʻoomi ʻana i ka umauma (100 a i 120 kaomi i kēlā me kēia minuke ma ka hohonu o 5 a 6 kenimika / 2 a 2.4 iniha no kahi kanaka makua), a e hoʻopili i kahi Automated External Defibrillator (AED) i ka wā e loaʻa ai. E ʻike i kā mākou kōkua mua i ka uila a CPR alakai.

Lawe i kahi papa

ʻO ka hoʻomaʻamaʻa lima lima i ka hoʻōla ʻana i ka cardiopulmonary (CPR), ka hana defibrillator waho (AED), a me ka puhi ʻana i ke kōkua mua e hāʻawi iā ʻoe i ka hoʻomanaʻo ʻana i ka ʻiʻo e hana ke helu kekona. E kelepona i kāu hui ʻĀpana Red Cross, St John Ambulance, a i ʻole ke keʻena kinai ahi kūloko e kākau inoa i kahi papa kōkua mua i hōʻoia ʻia.

Nīnau pinepine

Why do utility fire crews sometimes let a burning manhole keep burning instead of spraying water down the hole right away?

When firefighters arrive at a smoking or flaming electrical manhole, **they almost never pour water directly onto an energized underground electrical vault fire** for two life-saving reasons. First, the underground cables inside the manhole carry thousands of amps at 120V to 34,500V with no local fuse: spraying a solid stream of conductive water down the shaft risks electrocuting the firefighters and causing a massive **steam and arc-flash explosion** (water flashes 1,600 times in volume when hitting a 2,000-degree electric arc). Second, as long as an open flame is visible at the mouth of the manhole, the flammable pyrolysis gases ($\text{CO}$ and $\text{H}_2$) are burning off steadily at atmospheric pressure; **extinguishing the flame while the cables are still energized and hot causes unburned explosive gas to build back up inside the duct and detonate violently minutes later**. Fire crews first isolate the area, evacuate basements for carbon monoxide, and wait for utility high-voltage crews to cut power or inject inert nitrogen/CO2 before cooling the vault.

How can I tell if the white cloud coming out of a street manhole is a harmless winter steam leak or a dangerous rupture?

Look at three things: **velocity, sound, and debris**. A benign winter vapor plume occurs when cold rainwater or snowmelt drips onto the outside of an insulated underground steam pipe casing; it rises lazily like fog off a warm cup of coffee, makes little to no noise, and disappears within 1 to 3 meters (3 to 10 feet) above the street. By contrast, an active **high-pressure steam pipe rupture** sounds like a deafening jet engine or freight train, shoots a rigid, high-velocity white-and-gray column 10 to 90 meters (30 to 300 feet) into the air, shakes the pavement beneath your feet, and blasts mud, gravel, or water across the street. Treat any forceful, loud, or muddy steam plume as an immediate 100-meter (330-foot) evacuation emergency.

How do I treat a severe steam scald burn while waiting for paramedics?

High-pressure district steam causes deep second-degree and third-degree thermal burns in less than a second. Once you are safely out of the steam zone, immediately **cool the burn under cool, gently running tap water for 20 full minutes** (never use ice, ice water, butter, or ointments). Carefully remove rings, watches, belts, and non-adherent clothing before the skin swells, **but never peel off clothing that is melted or stuck to the burn**. Cover the cooled burn loosely with **clean, dry plastic cling wrap (food wrap) laid lengthwise** (never wrapped tightly around a limb like a tourniquet) or a sterile non-stick dressing to stop air from hitting raw nerve endings, keep the person warm to prevent hypothermia, and watch closely for any **hoarseness, coughing, stridor (high-pitched breathing), or singed nasal hairs**, which indicate a life-threatening inhalation airway burn requiring immediate hospital intubation. See our [severe burns first aid](../first-aid/severe-burns-and-chemical-flushing.md) guide.

Can I buy a cheap tool to test if a metal grate or wet sidewalk has stray voltage before walking my dog?

While electric utilities deploy specialized low-impedance contact-voltage detectors (`HD Electric LV-S-5` or multimeter shunt tests), a civilian can carry a standard pocket **Non-Contact Voltage Tester (NCVT "tic tracer" pen)** rated for **12V to 1,000V AC** or **50V to 1,000V AC**. However, **never rely on a pocket voltage pen to prove a wet grate is safe**, because if the entire surrounding wet sidewalk is floating at the same elevated voltage as the grate, a capacitive pen held by someone standing on that same wet potential may not beep. The only 100 percent reliable rule for dog owners is behavioral: **fit your dog with rubber winter dog booties** during salted snowmelt season, use a **non-conductive nylon or leather leash** (never a bare metal chain leash), and train your dog to walk strictly on the dry center strip of the concrete sidewalk away from all metal grates, manhole lids, and streetlight bases.

Nānā ʻia nā kumu

  • Institute of Electrical and Electronics Engineers (IEEE) Power & Energy Society: IEEE Std 1695 Guide to Understanding, Diagnosing, and Mitigating Stray and Contact Voltage a me nā pūʻulu hana ʻenehana e pili ana i ka pyrolysis insulation uwea lua, ka hana ʻana o carbon monoxide, a me ka dynamics pahū o lalo o ka honua.
  • Ka Hoʻomalu Palekana a me ke Ola Ola (OSHA, United States) a me ka National Institute for Occupational Safety and Health (NIOSH / CDC, United States): Hoʻopaʻa ʻia i ka Space / Manhole Komo Palekana (29 CFR 1910.269(e)), ka palena o ke kinoea puhi ahi ma lalo o ka honua, a me nā protocols decontamination fiber asbestos pilikia ma hope o ka haki ʻana o ka mahu.
  • International District Energy Association (IDEA) and Consolidated Edison / National Grid Urban Steam Engineering Standards: Kāohi a me ka pane ulia pōpilikia no Condensation-Induced Water Hammer (CIWH) i loko o nā kīʻaha mokumahu kalana kiʻekiʻe.
  • United States Environmental Protection Agency (EPA) a me ke Keʻena o ka Environmental Protection (NYC DEP / UK HSE): Hoʻokele olakino lehulehu i ka hāʻule ʻana o ka lepo chrysotile asbestos a me ke kūkulu ʻana i kahi kaʻawale HVAC ma hope o ka pahū ʻana o ka paipu mahu ma lalo o ka honua.
  • National Fire Protection Association (NFPA, United States) a me London Fire Brigade (United Kingdom): Nā kaʻina hana maʻamau no nā pahu pahu loulou uila ma lalo o ka honua, ke ahi o ka transformer vault, a me ka neʻe ʻana o ka carbon monoxide i loko o nā hale pili.

Nā alakaʻi pili