2_3 Bien Phap PCCC Cho Cong Trinh(1)

10-

2.3. CC BIN PHP C TH PHNG NGA CHY, N CHO CNG TRNH XY DNG

2.3.1. Gii php phng chy trong thit k qui hoch 2.3.1.1. Khong cch phng chy, chng chy gia cc nh v cng trnh Khong cch phng chy, chng chy gia cc nh v cng trnh c tc dng

ngn nga kh nng pht trin ca m chy sang cc nh, cng trnh bn cnh n thi im trin khai lc lng, phng tin cha chy v bo v cc nh, cng trnh bn cnh, ng thi to iu kin thun li cho vic c ng ca phng tin cha chy. Trong qui chun xy dng gi khong cch phng chy, chng chy gia cc nh v cng trnh l khong cch ly phng chng chy.

Trong thit k qui hoch khong cch ly phng chng chy cn thit gia cc nh, cng trnh c th gim nu c mt trong cc bin php sau:

- C lp t h thng cha chy hoc bo chy t ng. - Gim ti cht chy hoc gim mc nguy him trong qu trnh cng ngh. - Gim sc cha hoc thay i bin php bo qun hng ha. - Tng bc chu la ca nh v cng trnh. Tiu chun khng qui nh khong cch ly phng chng chy gia nh v cng

trnh sn xut i vi cc trng hp sau: + Nu tng din tch sn ca hai hoc trn hai nh, cng trnh c bc chu la III

n V khng vt qu din tch sn ti a gia cc tng ngn chy theo mc nguy him chy ln nht v bc chu la thp nht ca nh v cng trnh.

+ Nu tng ca nh, cng trnh c kch thc ln nht (cao v rng) hng v pha nh, cng trnh khc bn cnh l tng ngn chy.

+ Nu nh, cng trnh c bc chu la III, khng ph thuc vo mc nguy him chy ca qu trnh sn xut t trong , c tng ngn chy khng thm thu kh hoc c tng c xy bng knh blc hoc knh c ct thp vi gii hn chu la thc t khng nh hn 0,75 gi.

+ i vi nh, cng trnh c bc chu la I, II vi hng sn xut C, D. Khi thit k mt bng qui hoch tng th cn phi m bo c mt xy dng

hp l, m bo duy tr c khong cch ly phng chng chy cn thit hoc m bo an ton bng cc gii php k thut khc.

Tuy nhin khi thit k qui hoch cn cn nhc cc yu cu v b tr cc cng trnh c nguy him chy n so vi hng gi thnh hnh, bnh xy dng, trng thi ng giao thng v ngun nc, mng li cc n v phng, cha chy th v.v

2.3.1.2. Giao thng cung cp nc cha chy ngoi nh a) ng giao thng phc v cha chy - B tr ng cha chy: i vi khu dn dng, khong cch gia cc ng

khu vc xuyn qua hoc xen gia cc ngi nh khng c di qu 150m. i vi cng trnh cng nghip phi b tr ng cho xe cha chy chy dc theo mt pha nh, khi nh c nhp rng t 18m tr ln.

- ng cho xe cha chy phi c kch thc thng thy ti thiu l 3,25m chiu rng v 4,25m chiu cao.

11-

- ng ct mt ln xe khng vt qu 150m, cui ng ct phi c bi quay xe vi kch thc ti thiu trn mt bng l: hnh tam gic u mi cnh l 7m, hoc hnh vung kch thc 12x12m hoc hnh trn ng knh 10m.

- Qui chun xy dng qui nh trong qui hoch xy dng th, khi thit k h thng k thut th (giao thng, cp nc, cp in) phi kt hp vi vic m bo cc yu cu phng chy cha chy.

b) Cp nc cha chy Ngun nc cha chy phi lun m bo. Trng hp cn thit phi b tr b

d tr nc v my bm cha chy. Cn tn dng cc ao, h, sng d tr nc cha chy. Khu d tr ny phi m bo c lng nc d tr ti mi thi im, c ng cho xe cha chy lui ti ly nc v chiu su mt nc so vi mt t khng qu 4m, chiu dy lp nc khng c nh hn 0,5m.

Trn mng cp nc th, dc theo cc ng ph phi b tr cc hng ly nc cha chy (ngm di mt t hoc ni) v m bo khong cch sau:

- Khong cch ti a gia cc hng ti khu trung tm th loi I v II, khu c mt dn c cao l 100m; ti cc khu vc cn li 150m.

- Khong cch ti thiu gia hng v tng cc ngi nh l 5m. - Khong cch gia hng v mp ng (trng hp hng c b tr bn

ng, khng nm di lng ng) l 2,5m. Hng nc cha chy phi c b tr ni thun tin cho vic ly nc cha

chy. ng knh ng dn nc cha chy ngoi nh phi ln hn hoc bng 100mm. Lu lng nc cha chy ngoi nh ca h thng cp nc cha chy v s m chy cng mt thi gian c qui nh trong bng 12 ca TCVN 2622-1995.

H thng cp nc cha chy ngoi nh phi thit k theo mng li vng. Khi ng ng ca h thng cp nc cha chy ngoi nh khng qu 200m, cho php thit k ng ng ct, nhng phi d kin thnh mng li vng.

i vi cc cng trnh c yu cu phng chng chy cao, theo yu cu ca c quan phng chy cha chy a phng, ch u t cng trnh phi u t xy dng cc hng nc cha chy b sung, b d tr v my bm cha chy.

Phi thit k h thng cp nc cha chy cho nh, cng trnh dn dng, nh kho, cng trnh cng nghip. H thng cp nc cha chy bao gm h thng cp nc cha chy trong nh v ngoi nh. Cho php thit k h thng cp nc cha chy ring bit khi vic kt hp h thng cp nc sinh hot hoc sn xut khng c li v kinh t.

ng ng cp nc cha chy c th l ng ng p lc cao hay p lc thp. Trong ng ng cp nc c p lc cao th p lc cn thit cha chy l do my bm cha chy c nh to nn.

Trong ng ng cp nc cha chy p lc thp, th p lc cn thit cha chy l do my bm di ng hoc xe bm cha chy, ly nc t cc tr nc cha chy t ngoi nh.

Trong cc khu dn dng, lu lng nc cha chy bn ngoi ca h thng cp nc cha chy v s m chy cng mt thi gian c qui nh trong bng sau:

12-

Lu lng nc cho mt m chy (lt/giy)

Nh 1 2 tng c bc chu la

S dn

trong khu (1.000 ngi)

S lng m chy

trong cng mt thi gian

I, II v III IV v V

Nh xy hn hp

cc loi tng khng ph

thuc bc chu la

Nh xy t 3 tng tr ln

khng ph thuc

bc chu la

1 2 3 4 5 6

n 5 1 5 5 10 10

n 10 1 10 10 15 15

n 25 2 10 10 15 15

n 50 2 15 20 20 25

n 100 2 20 25 30 35

n 200 3 20 30 40

n 300 3 40 55

n 400 3 50 75

n 500 3 60 80

n 600 3 85

n 700 3 90

n 800 3 95

n 1000 3 100

+ Trong cc khu nh gm c nh mt, hai tng v nh nhiu tng khc nhau th

phi xc nh ring tng loi nh c tnh n s dn trong . Lng nc tnh cho ton khu l tng cng lng nc tnh cho tng loi nh

trong khu . + Lng nc v s m chy trong mt thi gian i vi khu dn dng trn

1.000 ngi, c xc nh theo yu cu ring: + S m chy cng mt thi gian trong th hay vng phi tnh c s m

chy cc cng trnh cng nghip, cng trng phi ph hp vi lng nc cha chy cn thit nhng khng c di tiu chun qui nh trong bng trn.

c) Tnh s lng m chy v lu lng nc cha chy - Trong cc khu cng nghip s m chy trong cng thi gian c tnh nh

sau: + Nu din tch khu t di 150ha th tnh mt m chy. + Nu din tch khu t t 150ha tr ln, th tnh vi hai m chy v lu lng

nc cha chy tnh cho hai ngi nh cn lng nc cha chy nhiu nht. Trong cc cng trnh cng nghip, lu lng nc cha chy bn ngoi ly t

tr nc cha chy, tnh vi nh cn lng nc cha chy nhiu nht v tnh cho mt m chy c qui nh trong bng sau:

[

13-

Lu lng nc tnh cho mt m chy (lt/giy) n v khi tch ca cng trnh (1.000m3) Bc

Chu la Hng

sn xut Di 3 T 3 5 T 5 20 T 20 50 Trn 50

I v II D, E, F 5 5 10 10 15

I v II A, B, C 10 10 15 20 30

III D, E 5 10 15 25 35

III C 10 15 20 30 40

IV v V E, D 10 15 20 30

IV v V C 15 20 25

Ch : i vi nh c tng ngn chy th ch tnh vi phn ngi nh i hi

lng nc cha chy ln nht. - Lng nc dng cha chy bn ngoi trng hc, bnh vin, nh vn ha,

c quan hnh chnh, nh ph tr ca cng trnh cng nghip c tn theo quy nh trong bng 13 v coi nh nh thuc hng sn xut C.

- i vi cc khu cng nghip hoc cng trnh cng nghip, trong c hng sn xut C, D, E m din tch khng qu 200.000 m2, lu lng nc dng cha chy bn ngoi nh khng qu 20 lt/giy v i vi khu dn c khng qu 8.000 ngi, th khng cn thit k h thng ng ng cp nc cha chy bn ngoi m c th s dng my bm hay xe bm cha chy ly nc t cc ngun nc thin nhin nh sng, h hay b cha nc, h nc nhn to cha chy vi iu kin:

+ C nc d tr cha chy trong cc ma theo quy nh + Chiu su ht nc khng qu 4m t mt t n mt nc v nc khng

cn qu 0,5m; + Phi c ch m bo cho xe bm hoc my bm cha chy n ly nc. - H thng ng ng cp nc cha chy bn ngoi, phi thit k theo mng

li vng. Khi ng ng cp nuc cha chy bn ngoi khng qu 200m, cho php thit k ng ng ct nhng phi d kin thnh mng li vng. Cho php t cc ng nhnh ct dn nc cha chy n tng ngi nh ring l, nu chiu di ng ng ct ny khng qu 200m, nhng phi c b cha nc hoc h cha nc d tr cha chy v c d kin thnh mng li vng.

Ch : + Trong giai on u t ng ng dn nc, c th t ng ng nhnh ct dn nc cha chy m khng hn ch chiu di nu c s tha thun ca c quan PCCC c trch nhim;

+ Trong khu dn dng nu s dn khng qu 10.000 ngi th cho php t ng ng nhnh ct;

+ ng knh ng dn nuc cha chy ngoi nh t nht 100mm. - Tr nc cha chy ngoi nh phi b tr dc theo ng giao thng, khong

cch gia cc tr khng qu 150m. Tr nc cha chy ngoi nh phi t cch ng t nht 5m v nn b tr ng t ng. Nu tr b tr hai bn ung xe chy th khng nn t cch xa mp ng qu 2,5m, ng ng cha chy phi chia thnh tng on v tnh ton s tr nc cha chy trn mi on khng qu 5 tr. Trong cc cng trnh cng nghip, th hay khu dn dng m lu lng

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nc cha chy bn ngoi khng ln qu 20 lt/giy th khong cch gia hai tr nc cha chy ngoi nh khng qu 120m.

- Nhng van kha nc t cc ng ng nhnh ct cng nh nhng van ln kha t ng ng khp kn phi b tr m bo mi on ng ch kha nhiu nht l 5 hng cha chy trn cng mt tng.

- p lc t do cn thit trong ng ng cp nc cha chy p lc thp t mt t khng c di 10m ct nc. Trong ng ng cp nc cha chy p lc cao, th p lc t do u ming lng ca hng nc cha chy t v tr cao xa nht thuc ngi nh cao nht phi bo m ct nc khng di 10m.

- Phi thit k ng ng cp nc cha chy bn trong nh trong cc trng hp sau:

+ Trong cc nh sn xut tr nhng iu quy nh trong iu 10.13 ca TCVN 2622 : 1995

+ Trong nh gia nh t bn tng tr ln v nh tp th, khch sn, ca hng n ung t nm tng tr ln;

+ Trong cc c quan hnh chnh cao t su tng tr ln, trng hc cao t ba tng tr ln;

+ Trong nh ga, kho hng, cc loi cng trnh cng cng khc, nh ph tr ca cc cng trnh cng nghip khi khi tch ngi nh t 5.000 m3 tr ln;

+ Trong nh ht, rp chiu bng, hi trng, cu lc b 300 ch ngi tr ln. - Khng thit k h thng ng ng cp nc cha chy bn trong nh trong

cc trng hp sau y: + Trong cc nh sn xut c s dng hay bo qun cc cht m khi tip xc vi

nc c th sinh ra chy, n, ngn la lan truyn; + Trong cc nh sn xut c bc chu la I, II v co thit b bn trong lm bng

vt liu khng chy m trong gia cng vn chuyn, bo qun thnh phm, bn thnh phm l vt liu khng chy;

+ Trong cc nh sn xut hng D, E c bc chu la III, IV, V m c khi tch khng ln qu 1.000 m3;

+ Trong nh tm, nh git cng cng. + Trong cc nh kho lm bng vt liu khng chy, cha cc hng ha khng

chy; + Trong cc trm my bm, trm lc sch ca h thng thot nc bn; + Trong cc nh sn xut v nh ph tr ca cng trnh cng nghip, khng c

ng ng cp nc sinh hot hay sn xut v vic cp nc cha chy bn ngoi ly sng, h, ao, hay b d tr nc.

- S hng nc cha chy cho mi im bn trong nh v lng nc ca mi hng c quy nh trong bn sau:

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Loi nh

S hng nc cha chy

Lng nc tnh cho mi

hng (lt/giy)

1. Nh hnh chnh cao 6 n 12 tng c khi tch n 25.000 m3

1

2,5

2. Nh gia nh cao t 4 tng tr ln, khch sn v nh tp th, nh cng cng cao t 5 tng tr ln c khn tch n 25.000 m3. Nh kiu n nguyn cao n 16 tng.

1 2,5

3. Bnh vin, cc c quan phng bn, nh tr, mu gio, ca hng, nh ga, nh ph tr ca cng trnh cng nghip c khi tch 5.000 m3 n 25.000 m3

1 2,5

4. Cc phng b tr di khn i ca sn vn ng c khi tch t 5.000 m3 n 25.000 m3 v cc gian th dc th thao c khi tch n 25.000 m3.

1 2,5

5. Nh an dng, nh ngh mt, nh bo tng, th vin, c quan thit k c khi tch t 7.500 m3 n 25.000 m3. Nh trin lm c din tch trng by di 500 m2.

1 2,5

6. Hi trng, cc gian khn gi c trang b my chiu phim c nh, c sc cha 300 n 600 ch. 1 2,5

7. Nh cc loi cao 12 16 tng. 2 2,5

8. Nh hnh chnh cao 6 12 tng vi khi tch trn 25.000 m3. 2 2,5

9. Khch sn, nh tp th, nh anh dng, nh ngh, bnh vin, nh tr, mu gio, nh ba tng, th vin, nh trin lm, cc loi ca hng, nh ga, trng hc c khi tch ln hn 25.000 m3.

2 2,5

Loi nh

S hng nc cha chy

Lng nc tnh cho mi

hng (lt/giy)

10. Nh ph tr ca cng trnh cng nghip c khi tch ln hn 25.000 m3. 2 2,5

11. Cc gian phng b tr di khn i sn vn ng v cc gian th dc th thao c khi tch ln hn 25.000 m3. 2 2,5

12. Nh ht, tp chiu bng cu lc b, nh vn ha, rp xic, phng ha nhc c trn 800 ch, vin nghin cu khoa hc.

2 2,5

13. Nh sn xut. 2 2,5

14. Cc nh kho c khi tch t 5.000 m3 tr ln cha vt liu d chy hoc vt liu phng chy bo qun trong cc bao b d chy.

2 2,5

16-

- p lc yu cu ca cc hng cha chy bn trong nh phi m bo c tia nc dy c vi chiu cao cn thit quy nh trong bng sau:

Tnh cht ngi nh v cng trnh Chiu cao cn thit ca ct nc phun dy c (mt)

Nh , cng trnh cng cng, nh ph c bc chu la I, II. 6

Nh , cng trnh cng cng nh ph v nh sn xut c bc chu la I v II trong qu trnh sn xut c s dng vt liu d chy v d gy ra chy.

Chiu cao cn thit c th phun n mt im cao nht v xa nht ca ngi nh nhng khng c nh hn 6m.

- Khi trong nh b tr trn mi hai hng nc cha chy hoc c trang b h thng chng chy t ng th h thng cp nc cha chy bn trong nh, d thit k ring hay kt hp phi thit k t nht hai ng dn nc vo nh v phi thc hin ni thnh mng vng.

- B tr hng cha chy trong nh phi m bo mi im ca gian phng c s hng nc cha chy n nh quy nh trong bn 14. Trong cc ngi nh khi tch t 1.000 m3 tr xung c sn xut hng C, hng D v E khng ph thuc vo khi tch trong gian bn hng hay kho cha hng di 25.000 m3 cho php mi im ch mt hng cha chy phun n.

- Cc hng cha chy bn trong nh phi b tr cnh li ra vo, trn chiu ngh bung thang, snh, hnh lang v nhng ni d thy, d s dng.

- Tm ca hng cha chy phi t cao 1,25m so vi mt sn. - Mi hng cha chy trong nh phi c t van kha, lng phun nc v cun

vi mm c di theo tnh ton. Trong mi nh, ng knh ng, chiu di cun vi mm, ng knh lng phi s dng cng loi.

- Tnh ton mng li cp nc phi cn c vo p lc lng nc cha chy cn thit, s m chy cng mt lc, thi gian dp tt m chy.

- Trng hp khng th ly nc trc tip t ngun cung cp nc c hoc ly trc tip t ng ng cp nc th nhng khng thng xuyn m bo lu lng v p sut th phi c tnh ton cn c vo lng nc cha chy ln nht trong ba gi.

Tnh ton cung cp nc cn thit cho cha chy phi ng thi m bo c lng nc dng cho sn xut v sinh hot nhng khng tnh nc dng ti cy, ti ng, nc dng lau chi sn nh, my mc. Ring nc dng tm, ra, v sinh ch tnh bng 15 % lng nc tnh ton.

Ch : Trong trng hp ng ng cp nc cha chy c p lc thp th cho php ly mt phn nc (khng qu 50%) dng cho sn xut cha chy nu iu khng lm cn tr cho sn xut.

- Thi hn phc hi nc d tr cha chy c quy nh nh sau: + Trong cc khu dn dng, cng trnh dn dng v cng trnh cng nghip hng

sn xut A, B, C khng qu hai mi bn gi. + Cc cng trnh cng nghip thuc hng D, E, F khng c qu ba mi su

gi. - My bm dng cp nuc sinh hot, sn xut v cha chy d ring bit

hay kt hp u phi c my bm d b, c cng sut ca my bm chnh. S lng bm d b c quy nh nh sau:

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+ Khi s lng my bm vn hnh theo tnh ton t mt n ba th cn c mt my bm d b;

+ Khi s lng my bm vn hnh t bn my tr ln th cn hai my bm d b: My bm cha chy chnh phi c ni vi hai ngun in ring bit, hoc ngun in d b trm pht in, hoc ng c d b trm my bm. Cho php dng my bm cp nc cha chy m khng cn my bm d b v my bm cha chy chnh, ch ni vi mt ngun in khi lng nc cha chy bn ngoi di 20 lt/giy hoc trong cc x nghip hng sn xut E, D m cng trnh c bc chu la I, II hoc trong nh sn xut khi lu lng nc cha chy bn ngoi khng qu 20 lt/giy.

- My bm cp nc cha chy, c th iu khin bng tay ti ch hoc iu khin t ng t xa.

- Ch : + Khi lu lng nc cha chy bn ngoi t 25 lt/giy tr ln, th nht thit my bm cha chy phi c b phn iu khin t xa, Khi , phi ng thi b tr b phn iu khin bng tay;

+ B phn iu khin my bm cha chy phi bo m cho my hot ng khng chm qu 3 pht k t khi c tn hiu bo chy.

- Xc nh lng nc d tr cha chy trong b cha v trn i nc, phi cn c vo tiu chun lng nc cha chy, s m chy trong cng mt lc, thi gian dp tt m chy v lng nc b sung trong thi gian cha chy. Khi lng nc d tr cha chy t 1.000 m3 tr ln, th phi phn chia ra hai b cha.

Ch : + C th thit k nc d tr cha chy chung vi nc sinh hot, sn xut nhng phi c bin php khng ch vic dng nc d tr cha chy vo cc nhu cu khc;

+ Khi tnh th tch ca b nc d tr cha chy, cho php tnh lng nc b sung lin tc vo b, ngay c trong khong thi gian dp tt m chy l ba gi;

+ Trong trng hp nc cha chy bn ngoi ly t cc h cha nc, hoc cc tr cha nc, m bn trong nh cn c h thng ng ng cp nc sinh hot v cha chy, th th tch ca b cha nc d tr phi m bo lng nc dng trong mt gi, cho mt hng cha chy v cc nhu cu dng nc khc.

- Kt nc p lc v b cha nc c my bm tng p dng cha chy phi d tr mt lng nc nh sau:

+ i vi cng trnh cng nghip, th nc d tr cha chy tnh theo lng nc cn thit cho hng cha chy trong nh v thit b phun nc t ng trong thi gian 10 pht u xy ra chy.

+ i vi khu dn c th nc d tr phi m bo cung cp cha chy cho mt m chy bn trong v mt m chy bn ngoi trong thi gian 10 pht vi lu lng nc cn thit ln nht, ng thi m bo c hi lng nc dng cho sinh hot ln nht.

- i nc s dng kh p p lc, th ngoi my p vn hnh phi c my p d b.

- B cha nc c p lc v i nc cha chy, phi c trang b thc o mc nc, thit b tn hiu mc nc cho trm bm hay lin lc vi trm phn phi nc. Nu i nc ni my bm cha chy tng p lc th phi thit k b phn iu khin t ng ct nc ln i khi my bm cha chy hot ng.

Ch : + Nu my bm cha chy t ng bm khi mc nc trong i b h thp, th khi lng nc d tr trong i c th ln bng 50% lng nc quy nh.

18-

+ Khi c h thng ng ng cp nc cho c x nghip nh my v khu cng nhn, th khi lng nc d tr trn i cha chy, ch cn c vo s hot ng ca cc hng cha chy bn trong x nghip, nh my m khng tnh n khu cng nhn.

- V tr v bn knh phc v ca b cha nc d tr, c xc nh ty thuc vo phng tin cha chy;

+ Nu dng xe bm cha chy, th bn knh phc v l 100m. + Nu c my bm di ng, th ty theo tng loi my bm m bn knh phc v

t 100m n 150m. Khong cch t h cha nc cha chy n nh c bc chu la III, IV, V hoc

n kho l thin lm bng vt liu d chy, t nht l 20m, v n ngi nh c bc chu la I, II, phi t nht l 10m.

2.3.1.3. Yu cu v giao thng v khong cch PCCC a) Yu cu v khong cch PCCC gia cc ngi nh v cng trnh cng nh

ng giao thng phc v cho vic cha chy phi c gii quyt kt hp vi yu cu ca quy hoch khu vc ni t cng trnh.

b) Khong cch PCCC gia nh v cng trnh l khong cch thng thy gia tng ngoi hay kt cu pha ngoi ca cc cng trnh .

Trng hp ngi nh c cc kt cu nh ra khi mt ngoi tng trn 1m v bng vt liu d chy th khong cch PCCC l khong cch ga hai mp ngoi kt cu .

c) i vi nh , nh dn dng khong cch PCCC gia cc ngi nh c quy nh trong bng sau:

Khong cch n ngi nh th hai c bc chu la, (m) Bc chu la ca ngi nh th nht I v II III IV V

I v II 6 8 10 10

III 8 8 10 10

IV 10 10 12 15

V 10 10 15 15

Ch : + Khong cch phng chy gia cc u hi nh khng quy nh nu tng hi ca ngi nh cao nht l tng ngn chy;

+ i vi nhng ngi nh hai tng, kt cu kiu khung v lp ghp tm thuc bc chu la V, th khong cch quy nh trong bng phi tng 20%;

+ i vi cc vng, cc a phng c gi kh nng (gi Ty Nam tiu vng kh hu xy dng IIB trong tiu chun thit k TCXD 49:1972) khong cch gia nh, cng trnh c bt k bc chu la no n nh v cng trnh c bc chu la IV v V phi tng 25 %;

+ Khi tng ngoi i din ca hai ngi nh khng c l ca th khong cch phng chy quy nh trong bng trn cho php gim 20%.

d) Cc ng ph chnh, ng khu vc phi cch tng nh v nh cng cng khng di 5m pha c li vo nh.

19-

e) Khong cch gia cc ng khu vc xuyn qua hoc xen gia cc ngi nh phi bo m khng qu 180m.

f) ng ct mt ln xe khng c di qu 150m, cui ng phi c bi quay xe vi din tch:

- Hnh tam gic u, cnh khng nh hn 7m - Hnh vung c kch thc cnh khng nh hn 12x12m - Hnh trn, ng knh khng nh hn 10m. g) ng giao thng khu vc xuyn qua ngi nh, qua cng hay hnh lang, phi

bo m: - Chiu rng thng thy, khng nh hn 3,5m - Chiu cao thng thy, khng nh hn 4,25m. h) i vi cng trnh cng nghip, khong cch phng chy cha chy gia cc

ngi nh c quy nh trong bng sau:

Khong cch gia cc nh v cng trnh, (m)

Bc chu la ca nh hay cng trnh bn cnh Bc chu la ca

ngi nh hay cng trnh I II III IV V

I + II Khng quy nh i vi nh v cng trnh hng sn xut D v E, 9 - (i vi nh v cng trnh hng sn xut A, B v C)

9 12

III 9 12 15

IV + V 12 15 18

Ch : i vi ngi nh v cng trnh c bc chu la I v II vi hng sn xut A, B v C quy nh trong bng trn, th khong cch gia cc ngi nh v cng trnh c gim t 9m xung 6m nu c mt trong cc iu kin sau:

+ c b tr h thng bo chy t ng c nh; + Khi khi lng cc cht d chy thng xuyn c trong nh t 10 kg/m2 sn tr

xung. i) Trong cng trnh cng nghip, b tr ng giao thng n tng ngi nh phi

kt hp gia yu cu ca cng ngh vi ng cho xe cha chy bn ngoi. k) ng cho xe cha chy bn ngoi phi m bo - Chy dc theo mt pha nh khi chiu rng nh nh hn 18m; - Chy dc theo hai pha nh, khi chiu rng nh bng hay ln hn 18m. l) ng giao thng cho xe cha chy hot ng phi bo m - Rng khng nh hn 3,5m; - Mt ng gia c phi bo m thot nc t nhin b mt. m) Khong cch t tng nh ti mp ng cho xe cha chy hot ng khng

ln hn 25m. Ch : + C th b tr ng ct cho xe cha chy hot ng khi cui ng c

bi quay xe theo yu cu nu im f trn y; + Phi b tr ng dn ti ni ly nc cha chy (h, ao, sng, b nc).

Ti v tr ly nc phi c bi quay xe theo yu cu nu iu 8.6.

20-

n) Khong cch ti thiu t cc kho l thin c cha vt liu d chy n cc ngi nh cng trnh c quy nh trong bng sau:

Khong cch t kho n nh v cng trnh, (m)

Bc chu la Kho

I II III IV

Than khi lng: - Di 1.000 tn - T 1.000 tn n di 100.000 tn

Khng quy nh

6

6 6

12 12

Than bn cm: - T 1.000 tn n di 100.000 tn - Di 1 000 tn

24 18

30 24

36 30

Than bn cc: - T 1.000 tn n di 100.000 tn - Di 1 000 tn

18 12

18 15

24 18

Ci g (g trn, g x): - T 1.000 m3 n di 100.000 m3

15

24

30

V bo, mt ca: - T 1.000 m3 n 5.000 m3 - Di 1.000 m3

18 12

30 13

36 24

Khong cch t kho n nh v cng trnh, (m)

Bc chu la Kho

I II III IV

Cht lng d chy: - T 1.000 m3 n di 2.000 m3 - T 600 m3 n di 1.000 m3 - Di 600 m3

30 24 18

30 24 18

36 30 24

Cht lng chy c: - T 5.000 m3 n di 10.000 m3 - T 3.000 m3 n di 5.000 m3 - Di 3.000 m3 - Di 1.000 m3

30 24 18 12

30 24 18 15

36 30 24 18

Ch : - Khng quy nh khong cch t cc ngi nh hay cng trnh n cc kho sau y:

+ Kho than di 100 tn + Kho cht lng d chy v chy c, c dung long di 100 m3 hoc kho

than hay than bn cm, than bn cc c dung lng di 1.000 tn m tng nh v pha cc kho ny l tng ngn chy;

- i vi cc kho g, kho than, khi xp cao hn 2,5m, khong cch ti thiu ch dn bng trang 35 i vi nh v cng trnh c bc chu la IV v V phi tng 28%;

21-

- Khong cch trong bng trn t kho than bn cm, than bn cc, kho g, kho cht lng d chy v chy c n nh v cng trnh c hng sn xut A v B cng nh n nh v nh cng cng phi tng 25%;

+ Khong cch t trm phn phi kh t n nh v cng trnh bn cnh, c p dng im 6 ca bng.

2.3.2. Gii php phng chy trong thit k kin trc v kt cu 2.3.2.1 Chn vt liu, cu kin c bc chu la cao Tnh chu la ca cu kin xy dng c c trng bng gii hn chu la. Gi

tr gii hn chu la ca tng cu kin c xc nh bng thc nghim. Gii hn chu la l khong cch thi gian (gi hoc pht) tnh t khi cu kin bt u th n khi mt kh nng chu lc hoc mt kh nng bo v. Nu ni tng ngn chy c gii hn chu la l 2,5 gi c ngha l tng ngn chy s b mt kh nng bo v (rn nt) sau 2,5 gi tnh t thi im bt u th tng ngn chy theo ch nhit tiu chun c quy nh theo TCVN 2622:1995 (bng 2).

Khi thit k xy dng phi chn vt liu v cu kin c bc chu la cao hn hoc bng gii hn chu la ti thiu v mc chy ca cc cu kin xy dng ch yu ng vi bc chu la ca nh v cng trnh c quy nh nh bng di y:

Gii hn chu la (pht) Bc

chu la ca ngi nh

Ct, tng

chu lc, bung thang

Chiu ngh, bc

v cc cu kin khc ca thang

Tng ngoi khng chu lc

Tng trong khng

chu lc (tng ngn)

Tm lt v cc

cu kin chu lc

khc ca sn

Tm lt v cc cu kin chu lc

khc ca mi

I 150 60 30 30 60 30

II 120 60 15 15 45 15

III 120 60 15 15 45 Khng quy nh

IV 30 15 15 15 15 Khng quy nh

V Khng quy nh

Ch : + Trong cc ngi nh c bc chu la III th sn tng mt v tng trn cng phi lm bng vt liu kh chy, sn tng hm hay tng chn tng phi lm bng vt liu khng chy, c gii hn chu la khng di 60 pht;

+ Trong cc ngi nh bc chu la IV, V th sn ca tng hm hay tng chn tng phi lm bng vt liu khng chy;

+ i vi cc ngi nh c tng hm mi m kt cu chu lc ca mi l vt liu khng chy th cho php lp mi bng vt liu d chy m khng ph thuc vo bc chu la ca ngi nh;

+ i vi nhng ngi nh cch ng xe la u my hi nc di 30m, th khng c lp mi bng vt liu d chy.

a) Vic tng thm gii hn chu la ca mt vi cu kin xy dng khng th xem nh tng bc chu la ca ngi nh hay cng trnh.

b) i vi cc bc chu la bc II cho php khng theo gii hn chu la nh quy nh trong bng trn khi:

22-

+ Dng kt cu thp khng c bo v trong nh sn xut mt tng, m khng ph thuc vo tnh ton nguy him v chy ca hng sn xut b tr trong ;

+ Dng kt cu thp trong nh sn xut nhiu tng khi trong b tr cc cng ngh sn xut hng A, B v C vi iu kin phi bo v kt cu thp bng vt liu chng chy c gii hn chu la khng di 45 pht tt c cc tng, tr tng trn cng;

+ Dng kt cu thp che mi, tng hm, mi v sn trong cc nh, cng trnh cng cng bc chu la I, II m cc kt cu c bo v bng cc vt liu khng chy hoc sn chng chy, c gii hn chu la khng di 4 pht. i vi cc nh v cng trnh cng cng mi tng tr ln th phi bo v cc kt cu bng vt liu chng chy, c gii hn chu la khng di 60 pht.

c) Gii hn chu la (pht) ca cc cu kin ch yu bng g cc nh mt tng ca cc cng trnh cng nghip, cng trnh cng cng, nh kho nh sn xut c bc chu la II c quy nh trong bng sau:

Cu kin g ch yu Bc chu la

ca nh, cng trnh Ct

Tng ngoi bng tm pa-nen

treo Mi

Tng chu lc bn trong (vch

ngn)

II 120 30 30 45 15

Ch : + i vi cc nh sn xut, nh v cng trnh cng cng, nh kho v hng sn xut B, cc cu kin nu trong bng trn phi c x l chng chy;

+ Khng cho php s dng cc kt cu nu trn i vi cc nh sn xut, nh kho c hng sn xut A v B.

d) Gii hn chu la ti thiu (pht) ca cc b phn ngn chy hay trong cc ngi nh thuc tt c nm bc chu la c quy nh nh sau:

Tn cc b phn ngn chy Gii hn chu la ti thiu, (pht)

1. Tng ngn chy 2. Ca i, ca s, cng tng ngn chy 3. Vch ngn chy 4. Ca i, ca s v vch ngn chy, ca ngn chy phng m trong cc nh xn xut hng A, B, C ca vo tng hm trn, ca mi chng chy. 5. Sn chng chy (sn gia cc tng, sn ca tng hm trn, sn tng lng) cc nh bc chu la I. 6. Sn chng chy (sn gia cc tng, sn ca tng hm trn, sn trn tng hm, sn tng lng) cc nh bc chu la II, III, IV.

150 70 45 40

60

45

Cc b phn ngn chy phi lm bng vt liu khng chy. e) Ca i, ca s, ca mi, mt sn, tng ngn lng, vt liu trang tr trn trn,

trn tng trong cc ngi nh thuc tt c cc bc chu la cho php lm bng vt liu d chy tr nhng b phn, kt cu nu ti mc d.

23-

f) Nhng b phn chu lc ca cu thang trong cc nh c bc chu la I, II v III (dm, chiu ngh, cu thang, bc thang) phi lm bng vt liu khng chy c gii hn chu la t nht 60 pht.

Trong cc ngi nh hai tng kiu cn h, cho php lm bc thang, chiu ngh bng g.

g) Tng, tng ngn v s ca bung thang my v bung b phn my nng b tr trong nh thuc bt k bc chu la no phi lm bng vt liu khng chy vi gii hn chu la t nht 60 pht. Nu thang my b tr ngoi nh th khng di 30 pht.

h) Trong mi ca cc nh thuc bc chu la I, II cho php s dng vt liu d chy cch nhit trn b mt ca cc tm b tng, x b tng v cc tm fibr ximng. Lp cch nhit trong mi tn hoc kim loi phi lm bng vt liu kh chy hoc khng chy.

Trong cc nh sn xut mt v hai tng thuc bc chu la I v II, nh kho 1 tng thuc bc chu la II c cu kin xy dng bng thp khng c lp bo v cho php s dng cch nhit bng vt liu d chy trn b mt cc tm thp, fibr ximng cng nh cc tm panen rng, i vi nh sn xut, nh kho thuc hng sn xut A, B, C c th s dng h thng t ng ti mt bng nc, khng cho php s dng cc vt liu tng hp d chy cch nhit nhng ngi nh ny.

i) Tng ngoi ca cc nh mt, hai tng thuc bc chu la II, III lm bng thp tm hoc tm fibr ximng th lp cch nhit phi s dng vt liu kh chy.

k) Trong nh kiu cn h t ba tng tr ln, tng ngn gia cc n nguyn phi lm bng vt liu khng chy c gii hn chu la t nht 60 pht. Tng ngn gia cc cn h phi lm bng vt liu khng chy c gii hn chu la t nht 40 pht. Trong nh c bc chu la II, III cao di su tng, cho php ngn cc phng ca cc tng mt cn h lm bng vt liu kh chy vi gii hn chu la t nht 15 pht.

l) Tng ngn bao che hnh lang gia ca nh c bc chu la I, phi lm bng vt liu khng chy vi gii hn chu la t nht 30 pht v ca nh c bc chu la II, III, IV phi lm bng vt liu khng chy hay kh chy vi gii hn chu la t nht 15 pht. Ring vi nh c bc chu la II ca hng sn xut D, E c th bao che hnh lang bng tng knh.

m) Trong cc ngi nh c bc chu la I, II, III. Sn v trn ca tng hm, tng chn tng phi lm bng vt liu khng chy vi gii hn chu la t nht 90 pht.

n) Trong cc ngi nh c bc chu la I, II, III cao t ba tng tr ln, sn ca bung thang, tin snh c li i t thang ra ca ngoi phi c gii hn chu la t nht 60 pht.

Ch : + Nh c bc chu la III cao n ba tng cho php sn, ca bung thang v

tin snh c gii hn chu la 45 pht, nu c mt li ra ngoi trc tip; + Trong rp chiu bng, cu lc b, nh vn ha, hi trng c bc chu la II th

sn ca phng khn gi v phng i phi lm bng vt liu khng c gii hn chu la t nht 60 pht;

+ Sn v trn cc kho thit b sn khu phi lm bng vt liu khng chy vi gii hn chu la t nht 60 pht;

+ Trong bnh vin, nh khm, cha bnh, nh h sinh, rp chiu bng, cu lc b, nh vn ha, ca hng khi c nhng gian b tr ni hi v cht t d chy th sn v trn ca nhng gian ny phi lm bng vt liu khng chy v c gii hn

24-

chu la t nht 90 pht cho nh v chu la II v III, cn i vi nh c bc chu la IV v V th gii hn chu la t nht 60 pht;

+ Trong cc cng trnh c bc chu la IV v V nu c tng hm v tng chn tng th sn trn cc tng phi lm bng vt liu khng chy, c gii hn chu la t nht 60 pht;

+ Trong hi trng, gian khn gi, phng hp, nu c tng hm mi th sn ca tng hm mi phi lm bng vt liu kh chy vi gii hn chu la t nht 60 pht.

o) Khung ca trn treo phi lm bng vt liu khng chy. Tm lt, trn treo cho php s dng vt liu d chy tr cc tm trn hnh lang cung, cu thang, bung thang, tin snh, phng i ca cc ngi nh c bc chu la I n IV.

Trong khong trng gia trn treo v mi, khng c t mng, ng ng dn kh, hn hp bi, cht lng v vt liu d chy.

p) Trong cc phng sn xut c s dng hoc bo qun cc cht lng d chy, sn phi lm bng vt liu khng chy. Trong cc ngi nh thuc tt c cc bc chu la, tr bc chu la V, khng cho php thc hin cng tc hon thin p lt tng v ca hnh lang chnh, bung thang, tin snh phng i, phng khch bng vt liu d chy. Khng cho php lp t sn tin snh bung thang, phng m bung thang bng vt liu d chy. Trong cc nh c bc chu la I n III khng cho php s dng vt liu d chy v kh chy hon thin mt tng ngoi.

Ca ca cc t tng t hng cha chy cho php lm bng vt liu d chy.

q) Trong khu vc cng nghip, cc cng tnh thuc bt k hng sn xut no khi bt u sn xut, u khng c s dng cc loi nh tm bng vt liu d chy.

2.3.2.2 Tnh ton nh c bc chu la cao Ngi nh c cu to t cc b phn kt cu khc nhau (tng, ct, dm, sn,

mi) chng c lm t cc vt liu thuc cc nhm bt chy khc nhau v c cc gii hn chu la khc nhau.

Theo mc bt chy v gii hn chu la ti thiu ca cc kt cu ch yu, cc ngi nh c phn ra lm 5 bc chu la; k hiu bng cc ch s I, II, III, IV, V. Bc I l bc chu la cao nht v gim dn theo th t ch s, bc V l bc chu la thp nht.

Ty theo chc nng ca ngi nh (nh , nh cng cng, nh ph tr sn xut, nh cng nghip), din tch, s tng, tnh chy nguy him ca hng sn xut, trang thit b cha chy t ng v.v xc nh mc chu la cn thit ca ngi nh.

Cn c vo bc chu la ca ngi nh quyt nh cc gii php an ton phng chy cha chy: s tng, din tch, chiu di, s lng, kch thc ca cc li thot nn v chiu di ng thot nn, khong cch ngn chy gia cc nh, lu long nc cha chy v.v

2.3.2.3 Thit k cc b phn ngn chy Cc b phn ngn chy ca ngi nh bao gm: Tng, vch ngn chy, sn

ngn chy, vng ngn chy; khoang ngn chy; l ca v ca ngn chy, vch ngn cch.

Cc b phn ngn chy phi lm bng vt liu khng chy, ca i, ca s, l ca v cc cu trc b tr cc b phn ngn chy phi c lm t vt khng chy hoc kh chy vi gii hn chu la quy nh.

25-

2.3.2.3.1. Phn khoang chy trong nh Khoang chy l mt phn khng gian ca nh, cng trnh c ngn cch vi

cc phn khng gian khc bng cc b phn ngn chy c gii hn chu la thch hp v cc l m trn u c bo v tng ng nhm hn ch s pht trin ca m chy v to iu kin thun li cho lc lng cha chy lm nhim v.

a) Tiu chun ha din tch khoang chy Din tch sn ti a ca mt khoang chy (Fmas.k/c) c tiu chun ha (quy nh

sn) th hin trong bng 11 ca TCVN 2622-1995 v bng 11.5.1 chng 11 ca Quy chun xy dng. Khi tiu chun ha khoang chy, cp n:

- Cng dng ca nh, cng trnh; - Bc chu la, s tng; - Nguy him chy n ca qu trnh cng ngh sn xut; - Vic b tr h thng bo chy, cha chy t ng.

iu kin an ton v din tch khoang chy: Fk/c tt Fk/c c/p Hai nguyn tc quy nh din tch sn ti a ca mt khoang chy theo din tch

khoang chy cho php v theo chc nng. - Khi quy nh din tch sn theo din tch khoang chy cho php, s lng tng

ngn chy c xc nh theo cng thc:

n = (Fs:Fk/c) - 1 Trong : Fs l din tch sn nh c xc nh theo h s thit k; Fk/c l din tch khoang chy cho php (din tch sn ti a gia cc

tng ngn chy) xc nh theo tiu chun. Din tch khoang chy trong nh , cng trnh cng cng ty theo loi nh, s

tng tiu chun cng quy nh c th. i vi nh cao tng din tch ln nht cho php ca mt khoang chy l: 1.000 m2 i vi nh , khch sn t 10 n 18 tng hoc cc cng trnh cng cng khc cao di 50m; 500 m2 i vi tng hm.

Khi cp n vic chia sn ra tng khoang theo chc nng ngha l khi chc nng ca cc phng khc nhau th tng ngn chy va ng vai tr phn chia ranh gii theo cng nng va ng vai tr ngn chy. Trong mt s trng hp c bit, li i gia cc khoang chy phi thng qua bung m ngn chy d iu p nu cc khoang c qu trnh sn xut nguy him n.

Khoang chy c lp trong nh sn xut ch quy nh i vi cc kho cha thnh phm.

Khoang chy c th chia ra thnh cc phn c din tch nh hn gi l n nguyn ngn chy nhm mc ch nng nga s xut hin chy hoc hn ch s pht trin ca m chy.

b) Tnh ton xy dng din tch khoang chy Khi xc nh din tch cho php ca khoang chy cn da vo iu kin an ton

sau: gim thit hi do chy gy ra mc thp nht, din tch ca khoang chy cn m bo m chy c dp tt trc khi sp mt trong cc kt cu chu lc. Khi din tch chy ln khng th tin hnh cha chy ng thi trn ton b din tch. Phng tin cha chy ch a cht cha chy ln mt on vi din tch xc nh F gi l din tch cha chy c hiu qu.

c) n nguyn ngn chy trong nh sn xut

26-

n nguyn ngn chy l nhng phn nh hn chia ra t khoang chy, gip ta xc nh nguyn nhn gy chy, gim xc sut gy chy v dp tt m chy c hiu qu nh:

- Cch ly cc qu trnh sn sut c mc nguy him chy - n khc nhau; - Cch ly cc qu trnh sn xut c mc nguy him chy - n vi cc qu

trnh sn xut c sinh nhit, c s dng ngn la trn hoc c to tia la; - Cch ly cc phng cha thit b in vi cc qu trnh sn xut c nguy him

chy- n; - Cch ly cc phng hnh chnh vi cc phng c nguy him chy - n; - Cch ly cc kho vi nh sn xut; - Chia nh, phn xng sn xut theo din tch; - Chia nh kho, phn xng sn xut theo cht cha chy. d) n nguyn ngn chy trong nh dn dng Nguyn tc chia n nguyn ngn chy trong nh dn dng nh sau: + Cch ly cc qu trnh c nguy him chy - n; + Cch ly cc phng c to nhit tha, to tia la hoc s dng ngn la trn

bng vch hoc sn ngn chy c gii hn chu la thc t 0,75 - 1,0 gi. Trong nhiu nh, cng trnh cng cng hin nay c s dng tng hm hoc mt s tng gn mt t lm gara t, do vy cn chia gara ny thnh nhng n nguyn cha khng qu 100 xe;

+ Cch ly cc phng cha thit b in; + Cch ly cc phng, kho cha hng; + Cch ly bung rc (i vi nh cao tng); + Chia nh thnh cc n nguyn theo din tch. 2.3.2.3.2. Tng ngn chy Tng ngn chy l mt trong cc b phn ngn chy c s dng rng ri,

chng c th chia thnh tng ngn chy khng chu lc, t chu lc v chu lc. Tng ngn chy khng chu lc l cc tng ch c chc nng ngn cch.

Trng lng ca n dn hon ton vo dm hoc khung chu lc. Tng ngn chy t chu lc l cc tng gnh ton b trng lng ca n

trong phm vi ngi nh v truyn xung dm mng. Tng ngn chy chu lc l cc tng m ngoi chc nng ngn chy, n cn

tham gia cng cc kt cu khc chu lc ca cng trnh. Loi tng ny thng s dng trong cc nh khng c ca tri (ca mi) hoc trong cc nh lp ghp, nh xy bng gch, t nhin.

Tng ngn chy cc loi, khng ph thuc vo cu to u c nhng yu cu chung nh sau: lm bng vt liu khng chy; c bn v gii hn chu la thc t thch hp khi ct qua cc cu kin chy hoc kh chy khc phi m bo khng thm khi v khng thm kh.

bn vng ca tng ngn chy theo TCVN 2622-1995 phi lm bng vt liu khng chy v c gii hn chu la thc t ti thiu l 150 pht.

Mt s quy nh v tng ngn chy: - Tng ngoi ca cc nh mt, hai tng thuc bc chu la II, III lm bng thp

tm hoc tm fibr ximng th lp cch nhit phi s dng vt liu kh chy.

27-

- Trong ngi nh c tng ngoi bng vt liu kh chy hay d chy th tng ngn chy phi ct qua cc bc tng y v nh ra mt tng khng t hn 30 cm. Cho php tng ngn chy khng nh ra mt tng ngoi nu tng ngoi c lm bng vt liu khng chy.

- Trong nh kiu cn h t ba tng tr ln, tng ngn gia cc n nguyn phi lm bng vt liu khng chy c gii hn chu la t nht 60 pht. Tng ngn gia cc cn h phi lm bng vt liu khng chy c gii hn chu la t nht 40 pht. Trong nh c bc chu la II, III cao di su tng, cho php tng ngn gia cc phng ca tng mt cn h lm bng vt liu kh chy vi gii hn chu la t nht 15 pht.

- Tng ngn bao che hnh lang gia ca nh c bc chu la I, phi lm bng vt liu khng chy vi gii hn chu la t nht 30 pht v ca nh c bc chu la II, III, IV phi lm bng vt liu khng chy hay kh chy vi gii hn chu la t nht 15 pht. Ring vi nh c bc chu la II ca hng sn xut D, E c th bao che hnh lang bng tng knh.

- Tng ngn chy phi c xy t mng hay dm mng n ht chiu cao ca ngi nh, ct qua tt c cc cu trc v cc tng. Cho php t tng ngn chy trc tip ln kt cu khung lm t vt liu khng chy ca nh hay cng trnh vi iu kin gii hn chu la ca phn khung tip gip vi tng ngn chy khng c thp hn gii hn chu la ca tng ngn chy.

- Tng ngn chy phi cao hn mt mi 60 cm nu mi hoc mt trong cc b phn ca mi v tng hm mi lm t vt liu d chy, khng t hn 30 cm nu tt c cc b phn ca mi v tng hm mi lm bng vt liu khng chy. Khi tng ngn hay vch ngn chy, trong c phng c trn treo, trn gi phi ngn cho c khng gian pha trn ca trn.

- L ca b tr trn mt tng tip gip vi tng ngn chy phi cch ch giao nhau gia hai tng ny theo chiu ngang t nht 4m v cnh ca phi c gii hn chu la it nht 45 pht.

- Trong tng ngn chy, cho php b tr cc ng ng dn khi, thng gi, ch tip gip gia tng v ng ng phi c bt kn bng va v gii hn chu la ca tng ch t ng ng khng di 150 pht.

- Thit k tng ngn chy phi tnh ton m bo bn vng khi c s ph hy t mt pha do chy sn, mi hay cc kt cu khc.

2.3.2.3.3. L m trn tng, vch ngn chy Mt vn c bit khc m bo chng thm thu kh cho tng ngn chy khi

trn tng c cc v tr rng cho cc ng ng k thut (ng dn nc, thot khi, thng gi, cha cp in ) v bng chuyn i qua l lm kn ch tip gip gia tng v ng ng, m bo gi hn chu la thc t ch t ng ng khng di 150 pht.

Trong cc b phn ngn chy c php lp t cc loi ca i, ca s, cng, l ca v van vi iu kin l cc loi ca v van ngn chy hoc c khong m ngn chy.

- Bo v ca i trn tng, vch ngn chy: v tr h dnh cho ca i trn tng, vch ngn chy cn c bo v bng ca ngn chy. Ca ngn chy cn c lm bng vt liu khng chy hoc kh chy c gii hn chu la thc t nh nht l 72 pht nu l ca trn tng ngn chy v khng nh hn 45 pht nu l ca trn vch ngn chy.

- Bo v cc ca cng ngh trn tng ngn chy: cho php b tr cc ng ng dn khi, thng gi nhng ch tip gip gia tng v ng ng phi c bt

28-

kn bng va v gii hn chu la thc t ca tng ch t ng ng khng di 150 phut. Khng c php t cc ng ng, mng ging vn chuyn cc cht chy th kh, lng, rn cng nh bi v cc vt liu d chy i qua tng sn v vng ngn chy.

- Trong cc b phn ngn chy, c php t cc loi ca i, ca s, cng, l ca vi iu kin l cc loi ca c vng ngn chy hoc c khong m ngn chy. Din tch chung ca cc loi ca v l trong b phn ngn chy khng c vt qu 25% din tch ca b phn , ca i v cng ngn chy phi l loi t ng kn, ca s ngn chy phi l loi khng t m.

- Tng, sn, ca ca khoang m phi l loi ngn chy. Trong khoang m, c lm ca kn bng vt liu d chy vi chiu dy khng nh hn 4cm nu cc ca ny m vo cc phng m trong khng s dng, bo qun cc cht v vt liu d chy cng nh khng c qu trnh lin quan n vic to ra cc bi d chy.

2.3.2.3.4 Sn ngn chy Sn ngn chy l mt trong cc b phn ngn chy dng hn ch s lan

truyn ca m chy trong nh theo phng thng ng. Sn ngn chy c b tr trong nhng trng hp sau:

- Nu din tch tng mt gia cc tng ngn chy ca nh nhiu tng c xc nh theo tiu chun ging nh i vi nh mt tng th sn ngn chy ca tng mt khng c v tr h thng tng v c gii hn chu la thc t khng nh hn 2,5 gi;

- Trong cc ngi nh c bc chu la I, II, III. Sn v trn ca tng hm, tng chn tng phi lm bng vt liu khng chy c gii hn chu la t nht 90 pht;

- Trong cc ngi nh c bc chu la III th sn tng mt v tng trn cng phi lm bng vt liu kh chy, sn tng hm phi lm bng vt liu khng chy c gii hn chu la thc t khng nh hn 60 pht. Nh c bc chu la III cao n ba tng cho php sn, ca bung thang v tin snh c gii hn chu la 45 pht, nu c mt li ra ngoi trc tip;

- Trong cc cng trnh c bc chu la IV v V nu c tng hm v tng chn tng th sn trn cc tng phi lm bng vt liu khng chy, c gii hn chu la t nht 60 pht;

- Trong cc phng sn xut, s dng hay bo qun cht lng d chy v chy c, sn phi lm bng vt liu khng chy;

- Gii hn chu la thc t ti thiu ca sn ngn chy (sn gia cc tng, sn tng hm mi, sn trn tng hm, sn tng lng) cc nh bc chu la II, III, IV l 45 pht;

- Trong cc ngi nh c bc chu la I, II, III cao t ba tng tr ln, sn ca bung thang, tin snh c li i t thang ra ca ngoi phi c gii hn chu la t nht 60 pht;

- Sn ca bung thang my v bung b phn my nng trong nh thuc bt k bc chu la no u phi lm bng vt liu khng chy c gii hn chu la thc t t nht 60 pht, nu thang my b tr ngoi nh th khng di 30 pht;

- Trong rp chiu bng, cu lc b, nh vn ha, hi trng c bc chu la II th sn ca phng khn gi v phng i phi lm bng vt liu khng chy c gii hn chu la thc t t nht 60 pht;

- Trong hi trng, gian khn gi, phng hp, nu c tng hm mi th sn ca tng hm mi phi lm bng vt liu kh chy vi gii hn chu la t nht 60 pht;

29-

- Trong bnh vin, nh khm cha bnh, nh hi sinh, ca hng, rp chiu bng, cu lc b, nh vn ha khi c nhng gian b tr ni hi v cht t d chy th sn v trn ca nhng gian ny phi lm bng vt liu khng chy c gii hn chu la thc t t nht 90 pht cho nh bc chu la II, III, cn i vi nh c bc chu la IV v V th gii hn chu la t nht 60 pht;

- Khung ca trn treo phi lm bng vt Iu khng chy. Tm lt, trn treo cho php s dng vt liu d chy, tr cc tm hnh lang chung, cu thang, bung thang, tin snh, phng ngh, phng i ca cc ngi nh c bc chu la I n IV;

- Cc b phn ngn chy dng hn ch s lan truyn ca m chy trong nh theo phng thng ng c th l nhng tng k thut bt k. Khi c hai sn ngn chy s to nn mt b phn ngn chy theo th tch v c th s dng trong bt k trng hp no khi c nhu cu v chia nh thnh khoang chy theo phng thng ng;

- Sn ngn chy gn kn vi tng ngoi v lm bng vt liu khng chy. Khi tng ngoi ca ngi nh c kh nng lan truyn chy hoc c lp knh th sn ngn chy phi ct qua tng v phn lp knh .

2.3.2.3.5. Cc b phn ngn chy cc b Cc b phn ngn chy cc b dng hn ch s lan truyn thng ca m

chy. Nhng kt cu ny trong nh v thng thng rt hiu qu trong mt khong thi gian ngn, trc khi m chy pht trin theo th tch.

Cc b phn ngn chy cc b bao gm: - Cc b phn ngn chy dng hn ch s lan truyn ca m chy theo b

mt v v tr rng ca cu kin: hn ch s lan truyn ca m chy theo b mt cu kin khi chng c lm bng vt liu chy v kh chy, tng on trn b mt ca cc cu kin c thay bng vt liu khng chy v c gi l ai ngn chy;

- Cc b phn ngn chy dng hn ch s chy loang ca cht lng: xung quanh bn, b cha ng c lp hoc quanh cm bn cha c cht lng chy hoc d chy thng s dng bao, loi tr s chy loang ca cht lng ra cc v tr xung quanh trong trng hp xy ra s c, Chiu cao ca bao khng nh hn 1m, chiu rng khng nh hn 0,5m. Thay vo v tr b t ca bao c th s dng tng b tng hoc tng vi chiu cao 1m. Th tch pha trong ca bao cn cha c tt c lng cht lng trong bn v phi tnh ton ti p lc ca cht lng ln thnh tng chn, Trong cc nh sn xut, nht l trong cc nh sn xut nhiu tng, khi thiu cc b ngn, cht lng chy c th chy loang ra tt c cc tng, chy loang vo bung thang, li i vi din tch ln. Bi vy m chy pht trin rt nhanh sang cc tng hoc nh, cng trnh bn cnh, l mi e da ln i vi cuc sng ca con ngi. Khi trong nh, cng trnh c t cc bn hoc thit b c cha cht lng chy hoc kh chy ha lng cn phi c cc gii php hn ch s chy loang ca cc cht lng trong trng hp xy ra s c. Khu vc sn nhng ni c t cc thit b ni trn cn c hn ch bi cc b ngn bng vt liu khng chy c chiu cao 0,14 0,15m hoc cao hn na ty theo dung tch cht lng cha trong thit b. Thay th vo v tr b ngn c th s dng cc khay cha t cc thit b cha cht lng chy vo trong

Ngoi ra, cc thit b ngn chy cc b cn bao gm: van ngn chy t ng c t ti v tr giao nhau gia ng ng thng gi vi sn v tng ngn.

2.3.2.4 Gii php kt cu, cng ngh v thit b a) S tng nh, chiu di gii hn, din tch xy dng ln nht theo bc chu la

ca cc cng trnh dn dng c quy nh trong bng sau:

30-

Chiu di gii hn ln nht ca ngi nh, (m)

Din tch xy dng ln nht cho php, (m2) Bc

chu la

S tng C tng ngn

chy

Khng c tng ngn

chy

C tng ngn chy

Khng c tng

ngn chy

I II Khng quy nh Khng quy

nh 110 Khng quy

nh 2.200

III 1 5 Khng quy nh 90 Khng quy

nh 1.800

IV 1 140 70 2.800 1.400

IV 2 100 50 2.000 1.000

V 1 100 50 2.000 1.000

V 2 80 40 1.600 800

Ch : Nh kiu n nguyn vi bc chu la I v II c kt cu chu lc ca mi khng chy th cho php khng xy dng tng ngn chy.

b) Bc chu la cn thit v s tng gii hn ca nh tr mu gio, bnh vin, nh h sinh, trng hc, ca hng, hi trng, nh vn ha, cu lc b, rp chiu bng ty thuc quy m cng trnh v c quy nh trong bng sau:

[[

Tn cng trnh v quy m Bc chu la ca cng trnh S tng hn ch

Nh tr v mu gio: + di 50 chu + Trn 50 chu

V IV III II

1 tng 2 tng

Bnh vin, nh h sinh: + Dui 50 ging + Trn 50 ging + Khng ph thuc vo s ging

V IV

III II

1 tng 2 tng

Khng quy nh

Nh hc: + Di 360 ch + T 360 ch n 720 ch + T 720 ch tr ln

V IV

III II

1 tng 2 tng 4 tng

Cng trnh vn ha (rp chiu bng, rp ht): + Di 800 ch + Trn 800 ch

III II

2 tng

Khng quy nh

Hi trng, cu lc b, nh vn ha: + Di 300 ch + T 300 ch n 800 ch + Trn 800 ch

V IV

III III

1 tng 3 tng

Khng quy nh

31-

Tn cng trnh v quy m Bc chu la ca cng trnh S tng hn ch

Cng trnh thng nghip (bch ha, lng thc, thc phm) khng ph thuc vo quy m

V IV III II

1 tng 2 tng 3 tng

Khng quy nh

c) Trong nh , khi c b tr cc phng s dng cng cng (ca hng, phng sinh hot chung, nh tr, mu gio), th cc phng ny phi ngn cch vi phng bng tng v sn khng chy, vi gii hn chu la khng di 45 pht.

d) S tng ti a cho php, bc chu la cn thit ca ngi nh v din tch sn ti a cho php gia cc tng ngn chy theo hng sn xut, phi theo quy nh ca bng sau:

Din tch ti a gia cc tng ngn chy, (m2)

Hng sn xut S tng

ti a cho php

Bc chu la

ca ngi nh

Nh 1 tng

Nh 2 tng

Nh cao trn 2 tng

1. A v B 6 Khng quy nh 2. A v B (trong trng hp khng sn xut ha cht v ch bin du kh)

6 II

3. A (c sn xut ha cht v ch bin du kh) 6 II

Khng quy nh 5.200 3.500

4. B (c sn xut ha cht v ch bin du kh) 6 II 10.400 7.800

Khng quy nh I II Khng quy nh

5. C

3 1 1

III IV V

5.200 2.600 1.200

3.500

2.600


6. D 3 1 1

III IV V

6.500 3.500 1.500

2.500

8.500


7. E 3 1 1

III IV V

7.800 8.500 2.600

6.500

3.500

Hng sn xut S tng ti a cho Bc

chu la Din tch ti a gia cc tng

ngn chy, (m2)

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php ca ngi nh

Nh 1 tng

Nh 2 tng

Nh cao trn 2 tng

8. F Khng quy nh

Xem bng 4 TCVN 2622: 1995

Khng quy nh

Ch : + Cc gian sn xut c cc thit b cha chy t ng (kiu mn nc hay kiu

xi nc) din tch sn gia cc tng ngn chy cho php tng 100 % so vi tiu chun quy nh bng trn;

+ Khi cc phng hoc gian sn xut c trang b cc thit b bo chy t ng, th din tch sn gia cc tng ngn chy cho php tng 25% so vi tiu chun quy nh bng trn;

+ Din tch sn tng mt gia cc tng ngn chy ca nh nhiu tng, ly theo tiu chun ca nh mt tng khi trn tng mt c gii hn chu la 150 pht;

+ i vi cc ngi nh bc chu la II, trong c lin quan n sn xut ch bin g th din tch sn gia cc tng ngn chy khng quy nh i vi nh mt tng. i vi nh hai tng, din tch sn gia hai tng ngn chy ti a l 7.800m2 cn i vi nh nhiu tng hn th din tch sn gia hai tng ngn chy ti a l 5.200 m2;

+ Trong cc ngi nh sn xut mt tng c bc chu la I v II, cho php khng thit k tng ngn chy. Quy nh ny khng p dng i vi nh c bc chu la II m trong sn xut ha cht, ch bin gia cng du kh hoc cc kho cha vt liu hay sn phm d chy; cc ngi nh sn xut gia cng ch bin g;

+ Trong cc ngi nh mt tng, bc chu la II, IV, V do yu cu k thut c th thit k cc vng ngn chy thay cho tng ngn chy, khi din tch sn gia hai vng ngn chy c ly theo tiu chun nh gia hai tng ngn chy quy nh trong bng trn.

e) Trng hp nhiu hng sn xut t trong cng mt ngi nh, hoc mt phn ca ngi nh uc gii hn gia hai tng ngn chy, bc chu la cng nh s tng cho php ca ngi nh, phi xc nh theo hng sn xut c mc nguy him nht v chy n b tr trong .

Ch : Khi din tch v khi tch cc phng c mc nguy him nht v chy, n khng ln hn qu 5% so vi din tch v khi tch ton nh hay mt phn nh gia hai tng ngn chy th khng theo quy nh ny. Khi , phi c nhng bin php phng chy ring bit (thng hi cc b ngn nga kh nng gy ra chy nhng phng ny v kh nng lan chy t nhng phng ny ra ton b ngi nh).

f) Khng cho php b tr bt k hng sn xut no, hay cc kho xenlul v vt liu tng hp xp d chy cc tng hm. Trng hp c bit, do yu cu dy chuyn cng ngh, c php b tr cc hng sn xut C, D, E tng hm v tng chn tng khi phi tun theo cc quy nh trong iu m trong phn ny.

g) Cc phng c cc hng sn xut A v B, nu cc yu cu cng ngh cho php, nn t gn tng ngoi nu l nh mt tng hoc t tng trn cng nu l nh nhiu tng.

33-

h) Trong cc phng thuc hng sn xut A v B phi thit k cc cu kin ngn d bung pha ngoi. Din tch cc cu kin d bung c xc nh qua tnh ton. Khi khng c s liu tnh ton th din tch ca cc cu kin d bung khng c nh hn 0,05 m2 cho mi mt mt th tch ca phng thuc hng sn xut A v khng nh hn 0,03 m2 i vi phng thuc hng sn xut B.

Ch : Ca s knh l thong c coi l c cu kin d bung khi dy ca knh l 3; 4 v 5 mm vi din tch tng ng khng di 0,8; 1 v 1,5 m2. Cc ca knh c ct thp khng c coi l cu kin d bung;

+ Cu kin d bung ca mi phi chia thnh tng c din tch khng qu 180 m2 mi ;

+ Ti trng tnh ton ca cc cu kin d bung khng qu 700 N/m2 i) Nhng phn sn nhng ni t my mc, thit b cng ngh c s dng cc

cht lng d chy, cht c phi c cc vch chn lm bng vt liu khng chy hoc cc khay hng. Chiu cao ca vch ngn v din tch gia cc vch ngn hoc din tch khay hng phi nu r trong phn thit k cng ngh.

j) Khi b tr trong cng mt phng cc hng sn xut c nguy him chy n khc nhau, th phi thit k cc gii php phng n v chy lan truyn cc b (bc kn thit b, dp chy cc b, thit b che chn ).

Khi b tr hng sn xut A, B v C trong cc phng ring ca ngi nh c bc chu la I v II, th phi ngn cch cc phng ny vi phng bn cnh bng vch ngn chy, c gii hn chu la t nht 45 pht, ca i cc tng ngn chy ny phi c gii hn chu la t nht 40 pht.

k) Khi thit k cc ca trn tng ngn chy v vch ngn chy khng th lp cc cnh ca chng chy gia cc phng c hng sn xut C, D v E th cc li i ny phi thit k bung m di khng di 4m, c trang b cc thit b cha chy t ng, vi lu lng nc cn thit l 1 l/s cho mi mt vung sn bung m. Cc vch ngn ca bung m phi c gii hn chu la khng di 45 pht.

l) Trong cc nh mt tng bc chu la IV cho php b tr cc phng c hng sn xut A v B vi din tch chung khng qu 300 m2. Trong trng hp ny cc phng ni trn phi c ngn cch bng vch ngn chy. Tng bao ca cc phng ny phi bng vt liu khng chy hoc kh chy.

m) Cc tng hm c b tr cc phng c hng sn xut C, D, E cc kho vt liu chy v vt liu khng chy trong bao b d chy, phi trang b cc thit b cha chy t ng v phi ngn cch bi vch ngn chy thnh tng phn vi din tch khng qu 3.000 m2 mi phn v chiu rng mi phn tnh c tng bao khng qu 30m. Ti cc phng trn cn thit k cc ca s rng khng di 0,7m v cao khng di 1,2m. Tng din tch ca ca s khng nh hn 2% din tch sn. Trong cc phng din tch trn 1.000 m2 phi thit k t 2 ca s tr ln. Trn ca tng hm phi c gii hn chu la khng di 45 pht.

Hnh lang phi rng t 2m tr ln c li thng ra ngoi hoc qua bung thang. Cc vch ngn hnh lang vi cc phng l vch ngn chy.

n) Cc ngi nh, cng trnh, cc thit b l thin m qu trnh sn xut c ta ra cc cht kh, bi v khi c nguy him v n v chy, cng nh cc kho du kh v sn phm ca du m, cc kho vt liu d chy, cc kho cht c u khng c b tr u hng gi thnh hnh i vi cc ngi nh, cng trnh khc.

o) Khng c b tr cc cn phng trong c s dng hay cha cc cht chy th kh v lng cng nh cc qu trnh c ta ra bi d chy bn di cc phng thng xuyn c ti 50 ngi.

34-

p) Khng c b tr ni hi vi p lc ln hn 0,7at hoc vi nhit nc trn 1150C trong nh , nh v cng trnh cng cng.

Khng b tr ni hi chy bng hi t di nhng gian nh, trong thng xuyn c ti 50 ngi.

Trong trng hp cng trnh cn thit phi c ni hi, th phi b tr trong gian nh ring, m bo yu cu phng chy, n.

q) Khng cho php b tr cc ng ng dn kh lng d bc chy, chy c di cc ngi nh v cng trnh.

r) Trong cc ng hm t ngi qua li, cho php b tr ng dn kh p lc di 6.105 N/m2 (6 Kg/cm2) cng vi ng dn khc v dy cp thng tin lin lc, vi iu kin phi c thit b thng gi v chiu sng trong .

s) Khng cho php b tr phi hp trong cng ng hm: - ng dn kh t vi cp in lc v chiu sng; - ng dn nhit vi ng dn cc cht lng d chy v chy c vi ng dn

lnh; - ng dn nc cha chy vi ng dn cht lng d chy v chy c v kh

d chy hoc cp in lc; - ng dn cht lng d chy v chy c vi cp in lc vi mng li cp

nc v thot nc; - ng dn xy vi ng dn kh d chy hoc vi ng dn cht c vi cp in

lc. t) Khng cho php b tr cc ng ng dn kh t, ng ng vn chuyn cc

cht c th gy chy, n hay nhim mi trng trn mt t. v) Cc ng ng dn cht lng d chy hay chy c, nu t ngm phi m

bo cch mt nn t nht 30cm v phi chia thnh tng on khng qu 60m, cc on phi cch nhau bng b ngn chy bc xung quanh ng ng bng vt liu khng chy.

Ch : ng ng dn cht c cng nh ng ng dn kh p lc trn 1 at, khng c b tr qua ng hm c ngi i b.

w) Cc ng dn cht lng d chy, chy c b tr trn cao phi cch tng nh c l ca t nht 3m v cch tng khng c l ca t nht 0,5m. Khng cho php b tr trn cao trong cc trng hp sau y:

+ ng ng dn cht lng, cht kh d chy v chy c trn cu cn, thp v ct bng vt liu d chy hay t trn tng v mi nh d chy;

+ ng ng dn hn hp c th gy chy v n vi ng dn cht lng v cc sn phm kh d chy, t trn hnh lang bn;

+ ng ng dn kh d chy. x) Cu vt ng t cc ng ng k thut, trong c ng ng dn

cht lng d bc chy hoc c th t chy c, th phi lm bng vt liu khng chy.

Ch : Khng c php t trong cng cu vt hay ng vn chuyn nhng ng dn cht lng v cht kh m hn hp ca chng c th gy n, chy hoc ng c;

35-

+ Cu vt ng t cc ng ng k thut, trong c ng ng dn cht lng, cht kh d bc chy hoc chy c th cho php b tr li i phc v ng ng ny cng trong cu vt hay ng vn chuyn;

+ Cu vt ng vn chuyn, trong c b tr cc thit b vn chuyn vt liu khng chy v vt liu c th t chy dng kt thnh ming (than, than bn, ci, dm bo ) hay ng dn cc cht lng khng chy, cng nh bng vn chuyn hay cu vt i b m khng phi l li thot nn, th c th lm bng vt liu d chy;

+ Trong trng hp cu vt, bng chuyn ny b tr phi trn cc ngi nh, th phi lm bng vt liu khng chy.

y) Cu vt hay bng vn chuyn lm bng vt liu kh chy hoc d chy, u phi m bo cc iu kin sau:

+ Cu vt hay bng vn chuyn chia thng tng on di khng qu 100m, cc on phi cch nhau bng khong ngn chy c chiu di t nht 5m;

+ Cu vt v bng vn chuyn ct nhau, d cng cao hay khc cao, th ch ct nhau u phi l khong ngn chy c chiu di t nht 5m;

+ Hnh lang v cu vt bng vt liu d chy phi m bo: Cch ngi nh c bc chu la III t nht 8m. Cch ngi nh c bc chu la IV, V t nht 18m.

+ Nu hnh lang, cu vt c khong cch nh hn quy nh trn, th phi lm bng vt liu khng chy. Khong cch nu trn khng p dng khi hnh lang, cu vt tip gip vi tng ngn chy hay tng bt kn khng c ca.

z) Cho php kt hp cu vt, ng vn chuyn vi ng b trong cc trng hp sau:

+ Hng vn chuyn phi l vt liu khng chy, n; + Phng tin vn chuyn phi an ton i vi ngi i b aa) Trong cc phng c hi ga, c s dng hay bo qun hi t, cc cht lng

hay bi d bc chy, d n, phi thit k bin php thng hi, thng gi loi tr kh nng chy, n trong cc phng . Khng c b tr cc ng dn nhit i qua cc phng ny. Trong trng hp phi t ng nhit i qua th phi cch ly cc ng ny vi mi trng xung quanh bng vt liu khng chy. Nu trong phng khng c nguy him v chy n, th c th cch ly ng dn nhit bng vt liu kh chy.

ab) Cc ng dn kh, bung cha kh, b phn lc khng kh v nhng b phn khc ca h thng thng gi, dn kh t vi nhit trn 300C, dn hi t, hi cht lng v bi d bc chy hay n cng nh nhng ph liu d chy (mt ca, v bo, len, bng ) u phi lm bng vt liu khng chy.

Trong nhng gian phng c nguy him v n v chy, tt c cc ng dn kh phi lm bng vt liu khng chy.

Trong cc trng hp khc, nhng b phn ca h thng thng gi c th bng vt liu khng chy.

Ch : Trong h thng thng gi c khng kh nng di 800C, th nhng b phn di y c th lm bng vt liu d chy:

+ B phn lc kh, phng lc c ngn bng vt liu kh chy; + Trong iu kin c bit v k thut, ng dn kh khng th lm bng vt liu

khng chy hoc kh chy hoc b g (nu nhng ng ny khng xuyn qua sn gc).

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+ Gia cc kt cu lm bng vt liu d chy v kh chy vi ng ng dn khng kh, hi ga c nhit trn 800C v ng ng dn nhng ph liu d chy phi ngn cch bng vt liu khng chy v cch nhit.

ac) ng ng phi thng ng v ng dn khng kh vo cc gian sn xut hng A, B v C phi t cho tng tng ring bit; tr nhng nh nhiu tng, trong c l sn gc dng cho mc ch k thut.

Trong trng hp ng ng chnh dn khng kh c nhng b phn ngn la, cho php dn khng kh nhp vo nhng gian sn xut hng A, B va C, bng ng nm ngang thng ng.

Nhng ng dn thng ng ring bit (ng thi v ng cp) mi tng, trong b tr sn xut hng D, E v F, c th ni vi ng ng chnh dn khng kh; nu cc thit b lm bng vt liu khng chy.

Nhng ng dn hi d ngng t, ng dn bi v cc cht khc c th gy ra hn hp c chy hoc n, do nguyn nhn c l hay ha khng c ni vo thit b thi chung .

ad) Trong cc phng khng c ca tri thng gi m b tr hng sn xut A, B v C, nht thit phi thit k cc ng thi kh v ng khi iu khin ng m bng tay hay t ng khi c chy. Tit din ngang ca ng thi ny c din tch t nht bng 0,2% din tch sn ca gian phng (nu phng khng c tng hm mi) v t nht bng 0,15% (nu phng c tng hm mi) .

Cc ng thi phi phn b u v lm bng vt liu khng chy hay kh chy; tit din ngang ca mi ng khng qu 2m2.

Ch : Cc gian phng c khu di 30m m k tip vi tng ngoi c cc l ca th khng p dng iu quy nh ny;

+ ng thi khi c s dng thay ng thi khng kh. ae) i vi nh v cng trnh cng cng t 5 tng tr ln, cho php t ng

thi kh chung thng ng, vi iu kin phi lp vo ng ng chnh nhng ng thng ng i t mi tng v xuyn qua hai tng. Cho php t kt hp vo mt ng ng chnh tp trung n ni vi ng ng thi t bn n nm tng.

Trng hp c nhng gian phng cch ly ring bit v trong cha cc cht d chy, th nhng gian phng phi t ng thi ring dn khi ra ngoi.

af) Cm c l t ng ng dn kh tng ngn chy v sn lm bng vt liu khng chy (k c cc b phn ngn chy khc).

Trong trng hp bt buc phi t ng dn kh xuyn qua b phn ngn chy, th bn trong ng dn kh phi c thit b ngn la (v ngn chy) v ch ng ng phi lm bng vt liu khng chy.

Ch : + Cho php t ng thng gi v ng khi trong tng ngn chy ca nh , cng trnh cng cng v nh ph tr khi chiu dy ti thiu ca tng ngn chy (tr tit din ng ng) ch khng c di 25cm, cn b dy phn ngn gia ng khi v ng thng hi ti thiu l 12cm;

+ Nhng l t ng dn nc b phn ngn chy phi c trt kn bng va.

ag) Cho php t ng ng thi kh chung cho cc cht hi t, hi ca cht lng v bi, nu hn hp ha hc ca cc cht khng bt la, khng chy hay n.

ah) Trong cc phng c sinh ra nhng cht d chy, n ta vo khng kh, th cc b phn ca my thng gi v thit b iu khin ca ng ng thng gi phi c thit k khng c kh nng to ra tia la. cc b phn lc ca h thng

37-

thi bi hay cc cht d bt la, d n, phi c phng php kh bi t ng, lin tc v ngn nga kh ngn pht tia la.

Trong cc phng sn xut c th gy n, cc ng c in ca h thng thi kh t trong phng cng vi my qut gi, phi l loi ng c chng n.

Ch : + i vi cc phng sn xut, khi vic kh bi t ng khng c li v mt kinh t, cho php kh bi tng thi k bng th cng nu cng sut ca b phn lc trong khong 15.000 m2/gi;

+ Nu ng c in s dng l loi thng thng, th ng c phi t cch ly vi phng my qut gi;

+ i vi cc hng sn xut A, B v C th kt cu ngn cch ca b phn qut gi phi lm bng vt liu khng chy.

ai) Khi thit k v thi cng phn in, cp nc, thng gi, cp nhit, chng st ca cng trnh phi tun theo quy nh trong cc tiu chun Nh nc c lin quan.

aj) Khi thit k h thng bo chy cho nh v cng trnh phi tun theo tiu chun TCVN 5788-1993 H thng bo chy, yu cu k thut v cc tiu chun chuyn ngnh c lin quan, ty theo yu cu thit k v quy nh ca tiu chun m chn cc gii php bo chy t ng, bn t ng hoc qua h thng thng tin lin lc thng dng.

ak) Ngoi h thng cha chy bng nc, trong nh v cng trnh phi c b tr cc phng tin, dng c cha chy chuyn dng khc. Ni b tr, s lng, chng loi theo cc quy nh trong TCVN 5760-1993 v hng dn ca c quan phng chy cha chy.

al) Vic thit k h thng cha chy bng nc, trong nh v cng trnh phi c b tr cc phng tin, dng c cha chy chuyn dng khc. Ni b tr, s lng, chng loi theo cc quy nh trong TCVN 5760-1993. H thng cha chy, yu cu chung v thit k, lp t v s dng, v cc tiu chun chuyn ngnh c lin quan.

2.3.2.4 Thit k h thng thng gi v iu ha khng kh a) H thng thng gi: ty bin php ht v y khng kh, h thng thng gi

c chia thnh hai loi: thng gi t nhin v thng gi c kh. Thng gi t nhin c thc hin nh tc dng ca p sut trng trng v p sut gi, cn thng gi c kh c thc hin nh qut gi hoc zect.

Thng gi t nhin c th l thng gi c t chc hoc thng gi t do. Thng gi t nhin c t chc l thng gi lin tc c thc hin nh cc v tr h hoc knh dn chuyn dng, cn thng gi t do trong phng uc thc hin qua ca s, ca i v qua cc khe h trong cu kin ngn cch bn ngoi.

Thng gi iu khin c t chc di tc dng ca p sut trng trng hoc gi c thc hin qua cc v tr h chuyn dng c gi l thng gi t nhin. Trng thi thng gi t nhin ny thng gp trong cc nh sn xut c nhit tha.

Thng gi c kh l s trao i khng kh c iu khin xy ra trong phng. Mc ch chnh ca thng gi c kh l duy tr cc thng s cho php ca khng kh trong phng. S trao i kh trong phng c thc hin nh h thng thng gi c kh.

H thng thng gi c kh l tp hp cc thit b dng ht, x l, vn chuyn, a khng kh vo hoc y ra. H thng ny c th c hoc khng c ng dn. Theo cng dng, h thng thng gi c kh c chia thnh hai loi: h thng thng gi vo v h thng y ra. H thng thng gi ht vo dng a khng kh t

38-

bn ngoi vo v h thng y ra dng a khng kh t trong phng ra bn ngoi. H thng thng gi c kh gm h thng thng gi chung v h thng thng gi cc b. H thng thng gi chung c p dng thng gi cho ton b th tch ca cn phng, khi ngun ta cht c hi nm ri rc hoc phn b theo ton b din tch ca cn phng. Cc trng hp khc b tr thng gi cc b.

Yu cu c bn v an ton chy i vi h thng thng gi l: - Ngn nga s tch t hi, kh c nguy him chy n trong phng; - Ngn nga s lan truyn mi trng nguy him chy n sang cc phng khng

c nguy c chy n; - Ngn nga s bc chy cc cht v vt liu chy vn chuyn trong h thng; - Ngn nga s lan truyn ngn la v sn phm chy khi c chy. Khi thit k h thng thng gi, vic b tr ca ht v ca y c ngha rt ln.

Nu cc cht kh, hi c hi hoc c nguy him chy thot ra trong phng c t trng ln hn t trng ca khng kh trong vng c ngi lm vic v ngun nhit trong phng c th duy tr dng khng kh nng chuyn ng n nh, bn vng th cn phi a ra ngoi 2/3 lng khng kh theo tnh ton t vng di (thng gi thc hin t nht mt ln trong gi) v y ra ngoi 1/3 lng khng kh t vng trn.

b) iu ha khng kh l s to nn v t ng duy tr cc thng s cn thit ca khng kh mi trng nh nhit , m, tc chuyn ng, thnh phn kh v ion. Tp hp cc thit b dng to nn v t ng duy tr cc thng s cn thit ca khng kh mi trng trong cc phng ca ngi nh, cng trnh c gi l h thng iu ha khng kh.

Khi tnh ton lng khng kh bn ngoi cn a vo phng duy tr cc thng s cn thit ca khng kh trong phng ti vng c ngi lm vic cn phi tnh n s phn b khng u ca nhit tha, m v cc cht c hi theo chiu cao v din tch cn phng. Nu trong phng c cc cht kh, hi, bi thot ra to vi khng kh thnh hn hp c nguy him chy n cn tnh ton kim tra lng khng kh bn ngoi cn a vo phng nng khng kh, hi, bi trong khng kh ca cn phng khng vt qu 5% so vi gii hn n di.

2.3.2.5 Thit k thot khi v chng t khi 2.3.2.5.1. Thot khi cho nh v cng trnh Thot khi cho nh, cng trnh xy dng l mt cng vic rt cn thit v n lm

chm li s lan truyn chy theo th tch, gip thot khi theo hng mnh mun, loi tr kh nng lan truyn chy ra khi phm vi phng b chy gp phn to iu kin thun li cho cha chy v thot nn cho ngi. Thot khi cho nh, cng trnh gm hai loi:

a) Phng php t nhin: da vo thng gi t nhin v vic kt hp cc gii php v qui hach v kt cu ca ngi nh thot khi t nhin. Tnh din tch cn thit ca ca thot khi trong nhng nh khng c ca tri l da vo s trao i kh t nhin ca nh, cng trnh. iu kin an ton khi tnh ton thot khi t nhin l cc phng ln cn phng b chy v ng thot nn khng b nhim khi. Nh vy gip vic t chc thot nn an ton cho ngi v ngn chn s pht trin ca m chy ra khi phng b chy trong sut thi gian bng gii hn chu la thp nht ca cu kin ngn cch bn ngoi. Mun vy khi tnh ton cn t gi thit v iu kin sau:

- Tnh ton vi iu kin m chy pht trin mnh nht.

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- Cc v tr h bn trong ca phng b chy l ng lan truyn chnh ca sn phm chy v l ca khng kh bn ngoi vo;

- p sut tnh theo chiu cao phng b chy thay i theo hm s bc nht, n c xc nh nhit trung bnh;

- Nhit khng kh qua ca i v v tr h cng ngh vo phng b chy bng nhit khng kh ngoi tri.

b) Thot khi cng bc: s dng h thng thot khi c kh vo mc ch thot khi gi l thot khi cng bc, hnh thc thot khi ny s tit kim c din tch ca cng trnh. Tnh ton h thng thot khi cng bc cn m bo cc yu cu an ton chy sau:

+ Ca van thot khi phi t sn ngn chy hoc mi . Van thot khi phi b tr phn tn u trn din tch cn phng nhng khng c nh hn 1 van/1.000m2;

+ Thot khi ra di dng ging phun, tuyt i khng s dng qut gi ng trc. V tr thot khi phi cch xa ca ht ca h thng thng gi ht vo;

+ Bung t qut ht khi nn tng k thut trn cng, cu kin ngn cch phi c gii hn lan truyn ngn la bng khng, gii hn chu la t nht 0,75 gi. Ca i phi l ca ngn chy c gii hn chu la t nht l 0,6 gi;

+ Cc h thng ng dn, cc mi ni, thit b chng n v.v cn phi m bo kn khi c sn phm chy vi nhit cao chuyn ng trong t nht 1 gi, cn vt liu cch nhit phi m bo khng b nung nng n nhit c th gy im chy mi.

2.3.2.5.2. Chng t khi cho nh, cng trnh chng t khi cho nh v cng trnh c th s dng h thng thot khi c

kh, to p sut d trong cc phng cn bo v v thc hin cc gii php k thut v kt cu, quy hoch cch ly ngun to khi gia cc tng v ng thot nn. Mun to p sut d trong bung thang b v ging thang my c th s dng h thng qut gi.

c bit ch chng thm thu kh sn ngn ca cc tng, ti nhng v tr lun chuyn gia cc tng ca h thng ng ng k thut cn c lm kn bng vt liu khng chy.Ca i trn ng thot nn phi kn, c thit b t ng ng, nu l ca pan knh th phi l knh c c thp.

Bin php c bn chng t khi cho nh, cng trnh l: - Hn ch s lan truyn ca sn phm chy trong nh, cng trnh; - Cch ly ngun to khi, cn c bit ch ti cc yu cu v cch ly i vi

cc phng t tng hm hoc tng lng.

2.3.2.6. Thit k an ton n Trong nh, cng trnh c th xy ra n do: s c k thut; khng thao tc ng

quy trnh Cc v n xy ra thng km theo cht ngi, b thng v ph hy cc my mc, thit b, nh ca. N hay xut hin nhng ch my mc c ta ra hi, kh, bi kt hp vi khng kh to ra hn hp n.

ngn nga nguy c chy n trong nh, cng trnh ngi ta p dng nhiu bin php phng ngay t khi thit k xy dng v trong qu trnh s dng h thng t ng thng xuyn duy tr ch lm vic n nh v ngn nga s thit hi ln o hu qu ca n.Thc cht qu trnh ny l nhm lm long nng hn hp chy trc khi t n gii hn n bng cc cht cha chy.

40-

Khi thi k an ton n cn cp n nhng gii php sau: - Din tch ca an ton n; - Trng lng tm d bung; - Tng v mi d bt; - Ca knh chng n; - B tr an ton cho n.

2.3.2.7. Cp nc phng ha bn trong nh Phi thit k h thng cp nc cha chy bn trong nh trong cc trng hp

sau: + Trong cc nh sn xut, tr quy nh trong iu 10, 13 ca TCVN 2622-1995; + Trong nh gia nh t 4 tng tr ln v nh tp th, khch sn, ca hng

n ung t 5 tng tr ln; + Trong cc c quan hnh chnh cao t 6 tng tr ln, trng hc cao t 3 tng

tr ln; + Trong nh ga, kho tng, cc loi cng trnh cng cng khc, nh ph tr ca

cc cng trnh cng nghip khi khi tch ngi nh t 5.000m3 tr ln; + Trong nh ht, rp chiu bng, hi trng, cu lc b 300 ch ngi tr ln. S hng nuc cha chy cho mi im bn trong nh v lng nuc ca mi

hng uc quy nh trong bng 14 ca TCVN 2622-1995. Khi trong nh c b tr 12 hng nc cha chy hoc c trang b h thng cha chy t ng th h thng cp nc cha chy bn trong nh, d thit k ring hay kt hp phi thit k t nht 2 ng dn nuc vo nh v phi thc hin ni thnh mch vng.

Cc hng nc cha chy trong nh phi b tr cnh li ra vo, trn chiu ngh bung thang, snh, hnh lang v nhng ni d thy, d s dng. Tm ca hng cha chy phi t cao 1,25m so vi mt sn.

Lng nuc cn d tr cha chy phi tnh ton cn c vo lng nc cha chy ln nht trong 3 gi.

i vi nh cao tng cn tun theo cc quy nh trong TCVN 6160-1996 Phng chy cha chy nh cao tng. Yu cu thit k.

2.3.3. Nhng yu cu phng chy, cha chy khi t chc cng trng xy dng

2.3.3.1. Nguy c chy trn cng trng xy dng Trong xy dng hin nay v ang s dng nhng vt liu v kt cu khng

chy lm gim s nguy him v chy trn cng trng. Tuy nhin trn cng trng xy dng vn cn s dng nhiu loi vt liu chy, d bt la, cc cht lng, sn cc loi, nha, matt, vt liu bi trn, g cy, cp pha, tranh tre, na, l l hng lot tc nhn c nguy c chy khi gp la.

Trong nhng iu kin thch hp mt s cht chy c th to ra vi khng kh nhng hn hp nguy him n, khi chng tip xc ngun la c th chy vi vn tc ln gy n.

Trn cng trng xy dng cc ngun la c th l: ngn la trn khi t chy ph thi vt liu xy dng, khi un nu bitum; tia la to ra do ma st hoc va p; phn khng chy ca nhin liu ng c t trong; s gia tng nhit kh nn khng kh trong my nn kh khng c lm ngui tt v.v S bc chy cc hn hp

41-

chy ch c th xy ra khi ngun la c nhit lng v nhit t nng hn hp chy n nhit t bc chy.

Nguy c chy do in (mng in lm v thit b) l do tc ng nhit hoc tia la in trong nhng iu kin thun li c th lm bc chy vt liu chy, thm ch gy n trong mi trng nguy him n. i khi chy do dy dn in b qu ti, chng nng ln, cht cch in c th b chy gy ra chy hoc do chy gy ra chp mch gia cc pha gy ra ngn mch v chy. Ngn mch cn xy ra khi cc vt dn in ri vo dy trn to thnh mch kn. in tr tip xc qu ln cng d sinh ra chy.

2.3.2.3. Bin php phng chy trn cng trng xy dng ngn nga kh nng pht sinh chy trn cng trng xy dng cn phi: - Hn ch s lng vt liu chy d tr nh: g, tranh, tre, na, l, cc loi cht

lng d chy v kh chy; - Kp thi thu gom v a ra ni an ton hoc tiu hy vt liu, rc ri chy

c; - Kp thi loi thi hi du, dung mi v cc cht lng chy v d chay to ra khi

tin hnh cc cng vic hoc khi bo qun chng; - Khng cho php t la khng ng quy nh trn cng trng; - Quy nh ni ht thuc ring cng nh nhng ch s dng la (nu bitum,

matt v cc loi vt liu khc); - Loi tr nguyn nhn to ra tia la khi cc ng c t trong, thit b in ang

hot ng; - Loi tr nguyn nhn gy n cc my nn kh, bnh cha kh v cc thit b p

lc khc; - phng xy ra s c i vi cc dy dn v cp bc in khng c

chng t nng n nhit qu 60 - 1000C; - bo v dng in khi qu ti v ngn mch nn dng cu ch an ton v

rle t ngt (ptmt) mc ni tip vo mng; - phng tnh in c th thc hin cc bin php sau: + Truyn in tch tnh in xung t; + Tng m khng kh trong cc phng c nguy him tnh in ln 70% hoc

lm m cc vt trong phng; + Phi ni t cc b phn kim loi ca dy curoa, cn ai da th bi lp du dn

in c bit ln b mt ngoi trong lc my khng hot ng; - Trong cc cng trng khi s dng my bm va hoc bm b tng ln cao

bng ng cao su c th to ra tnh in v tch ly trn ng cao su, nn phi qun lp dy kim loi vi bc qun l 10cm, gn mt u vo vi phun v u kia vo thn my bm.

2.3.3.3. Bo qun vt liu chy trn cng trng xy dng Trn cng trng xy dng vt liu xy dng thng c b tr cc kho, bi

hoc trm cung cp vt t nm ti v tr thun li nht cho thi cng xy dng. i vi vt liu chy, khi b tr kho bi cn ch nhng im sau:

+ Khong cch chng chy gia cc kho l thin cha cc vt liu chy n cc ngi nh v cng trnh c quy nh nh sau:

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Khong cch t nh, cng trnh (m) vi cp chu la Kho Dung tch kho (m3)

I - II III IV - V

Vt liu g, vn, ci 1.000 - 10.000

di 1.000 18 12

24 16

30 20

Vt liu d chy (v bo, mn ca )

1.000 - 5.000 di 1.000

18 13

30 16

36 24

Cht lng d chy 1.000 - 2.000 600 -1.000 di 600

30 24 18

30 24 16

36 30 24

Than (tn) 1.000 - 10.000

di 1.000 6

khng quy nh 6 6

12 12

Than cm (tn) 1.000 - 10.000

di 1.000 24 18

30 24

36 30

+ Cc cht lng v d chy phi bo qun trong b hay thng kn. Kho cha,

bo quan cht lng chy ch c lm t vt liu khng chy. Kho c th lm chm di t na chm, na ni; ni trn mt t. Kho chm l kho m im cao nht ca b hay thng cha thp hn mt t gip t 0,2m tr ln. Kho na chm, na ni l kho m b hay thng cha c chn su xung t hn na chiu cao ca chng. Kho ni l kho m y b hay thng cha c chn su xung t hn na chiu cao ca chng. Trong cc kho ny th kho chm l t nguy him nht;

+ Khi nhit khng kh bn ngoi thay i, khi y v tho cn b s lm thay i p lc bn trong cc b kn do c th gy bin dng thnh b. Cho nn b cha cc cht lng chy v d chy phi c van thng hi;

+ Cho php bo qun bnh cha kh trong cc kho kn ring cng nh cc kho bi h c mi che. Kho bnh cha kh cn t cch xa cc cng trnh ang thi cng ang thi cng ang thi cng v nh tm t nht 20m, cch kho, nh c cha cht lng chy v d chy v nh 50m, cch cc nh cng cng l 200m;

+ Khi m cc thng cn phi dng c bng ng thau hoc dng c chuyn dng m, trc khi m np thng cn bi mt lp m dy 2-3mm.

Gii hn chu la v nhm chy ca vt liu v cu kin xy dng tra theo bng sau:

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Danh mc kt cu

Chiu dy hay kch thc ti thiu ca

mt ct kt cu (cm)

Gii hn

chu la (pht)

Nhm chy

1. Tng v tng ngn: Tng v tng ngn bng gch silict, gch thng v gch t st rng.

6,0 11 22

145 150 330

Khng chy

2. Tng bng t nhin, b tng nh v khi snh, khi gch xy nh vi ct liu b tng nh, bng vt liu bo n kh chy hay khng chy.

33 6

11 22 33

660 30 90 240 420

Khng chy

3. Tng v tng ngn: B tng, b tng ct thp hay b tng hc, cng nh tng panen hay khi b tng v b tng ct thp. (xem ch thch 1).

2,5 5 6

11 15 17 22

18 36 45 150 222 270 360

Khng chy

4. Tng panen c mt ct c bng b tng nh t ong: a) Bng b tng kramzit hay b tng x ht c khi lng th tch 1.500 - 1.800 kg/m3. (xem ch thch 1) b) Bng b tng t ong hay b tng nh c khi lng th tch 900 - 1.200 kg/m3. (xem ch thch 1) c) Cng vt liu trn vi khi lng th tch 700 - 900 kg/m3. (xem ch thch 1).

2

20

20

270

360

360

5. Tng khi c mt ct ng bng b tng t ong c khi lng th tch l 900 - 1.200 kg/m3.

30 40

480 660

Khng chy

6. Tng panen gch nung c ct, gch silicat v gch t st thng (xem ch thch 1)

16 222 Khng chy

44-

8. Tng panen ba lp, vi khung bng ximng v p hai bn bng xi mng aming vt cht thp khi lp bo n: a) T tm bng khong khng chy hay kh chy b) T cht do xp

12

45 30

Khng chy Kh chy

9. Tng panen ba lp vi khung g v p hai mt xi mng aming, cht tm bn trong bng vt nh, tm ngoi nh hnh nhm vi lp bo n: a) T tm bng khong khng chy v kh chy hay tm b tng thy tinh b) T cht do xp

60

30

Kh chy

Kh chy

10. Tng v tng ngn bng tm xi mng aming hay tm thp (phng hay lng sng) khung thp;

15

Khng chy

11. Tng che mi v tng ngn bng gch, khi b tng v khi thin nhin vi khung thp: a) Khng c lp bo v b) t tng dy nht khe tng khng c lp bo v hayngn tng vi chn khung. c) Lp trt bo v dy 2cm trn lp thp d) Bng gch ng khi b dy ng l 6,5cm e) Bng gch ng khi b dy ng l 12cm

15

45

60 150 360

Khng chy

Khng chy

Khng chy Khng chy Khng chy

Danh mc kt cu


mt ct kt cu (cm)

Gii hn

chu la (pht)

Nhm chy

7. Tng panen 3 lp gm tm b tng ct thp g v lp bo n t bng khong khng chy hay kh chy hay tm fibrlt; a) i vi tng panen b) i vi tng chu lc khi b dy lp b tng bn trong 10cm bng b tng mc 200 v chu ng lc nn 25 Kg/cm2 v t hn (xem ch thch 15) c) Cng vt liu trn khi b dy 14cm bng b tng mc 300 v chu ng lc nn 100 kG/cm2 v t hn (xem ch thch 15).

15 22

25

27

Khng t hn 60

Khng t hn 150

27

Khng chy

Khng chy

Khng chy

45-

Danh mc kt cu


mt ct kt cu (cm)

Gii hn

chu la (pht)

Nhm chy

12. Tng ngn bng loi thch cao, x thch cao v thch cao si khi hm lng hu c n 8% khi lng

5 8

10 11

78 132 162 180

Kh chy

13. Tng ngn t khi knh xy dng 6

10 15 15

Kh chy

14. Tng ngn t khi xy kramzit rng. (xem ch thch 5)

8,5 4

6,5 8

30 60 90 120

Kh chy

15. Tng v tng ngn fibrlt hay x thch cao vi khung g trt va hai mt

10 10

45 36

Kh chy

16. Tng v tng g ngn, c trt va hai mt, kh b dy lp trt 2cm

15 20 25

45 60 75

Kh chy

17. Tng v tng ngn khung g trt hay p hai mt bng va thch cao kh hay fibro xi mng vi ct liu: a) T vt liu d chy b) T vt liu khng chy

30 45

18. Ct v tr gch, mt ct (cm) 22x22 22x23 33x88 33x45 45x45

150 180 270 315 390

Khng chy

19. B tng v b tng ct thp trong c ct cng trng ti: a) Khng qu 75% mt ct quy nh (cm) 20x20 20x30 b) Khng qu 75% mt ct quy nh (cm) 20x20 20x30 20x40 20x30 v 20x50 30x50 40x40

25 - - - - - - -

75 150

75 105 150 180 210 210

Khng chy

Khng chy

46-

Danh mc kt cu


mt ct kt cu (cm)

Gii hn chu la (pht)

Nhm chy

20. Thp khng c bo v khi b dy cu kin nh nht l: n 12 mm t 13 n 20mm t 21 n 30mm t 31 n 50mm

- - - -

15 18 20 24

Khng chy

21. Thp c bo v: a) Trt trn mt li hay tm b tng dy b) Gch nhiu l dy c) Tm thch cao dy d) Tm thch cao dy

2,5 5 6 7 6

11 3 6 8 4 5 7 8

45 120 150 180 120 315 60 24

228 66 90

120 150

Khng chy

Khng chy

Khng chy

Khng chy

22. Ct g c mt ct khng t hn 20x20 cm c bo v bng lp trt dy 2cm

10 -

192 60

Kh chy

23. Sn v mi t tm phng b tng ct thp lp rp mt ct c, khi b dy ca lp b tng t cnh thp nht t tm b tng chu lc ko (xem ch thch 9).

20mm 30mm 40mm 50mm

10 - - -

64 - 78 78 - 114

108 - 174 114 - 222

Khng chy

24. Sn hay mi t tm b tng ct thp lp ghp (tm panen) vi g chu lc dc pha di cng nh dm ngang, x dc khi chiu dy ca lp b tng t pha thp nht hay t cnh bn n tm ct thp chu lc dc. (xem ch thch 10)

6,5 10 10 10 16 16 16

20 v cao hn 20 20 20 20

30 36 - 42 36 - 42 42 - 48 48 - 54 42 - 54 48 - 72 66 - 84 48 - 60 66 - 78

84 - 108 102 - 108 132 - 144

Khng chy

47-

Danh mc kt cu

Chiu dy hay kch thc ti thiu ca mt

ct kt cu (cm)

Gii hn chu la (pht)

Nhm chy

25. Sn v mi trn dm thp ngang (x dc, ko) khi cc tm khng chy: a) Khi dm ngang, x dc, ko khng c bo v b) Khi dm ngang ca sn trn li (dn) c bo v bng lp b tng hay lp trt dy:

35mm 10mm 20mm 30mm

6,5 - - -

15

36 45 90

150

Khng chy

26. Sn g vi vn lt sn hay tm lt v trt trn vn lt hay trn li, khi b dy lp trt 20mm. 45

Khng chy

28. Mi t cc tm fibr xi mng hay cc tm tn trn dm thp ngang (x dc, ko) khng c bo v. 15

29. Mi t panen ba lp vi khung fibr xi mng dy 10cm, vt thp c nh vi lp bo n t cht do xp

14 30 Kh chy

30. Mi xi mng li thp khng c bo v pha dI 2 36

Khng chy

31. Kt cu cu thang thp: dm cu thang, dm ngang c bo v bng lp trt dy 1cm. Lp l ca, ca s, ca tri, ca hm.

90 Khng chy

32. Lp l ca bng khi knh rng khi xy bng va xi mng v t ct thp ngang trn b dy khi tch

6 10

90 120

Khng chy

33. Lp l ca bng cnh thp mt lp trong b tng ct thp vi knh c ct kp knh bng ct thp, inh tn hay kp

10 45 Khng chy

34. Lp l ca bng cnh thp mt lp trong b tng ct thp vi knh c ct kp knh bng cnh hai lp - 72

Khng chy

35. Lp l ca bng cnh thp mt lp hay cnh b tng ct thp vi knh c cht kp kinh bng inh thp.

36. Lp l ca bng cnh thp vi mt lp hay cnh b tng ct thp vi knh cht c nh, kp knh bng ct thp ch hay inh thp tn sit.

- 15

37.Ca i, ca np, cng vi tm cnh thp rng gia (c lp mng khng kh) - 30

Khng chy

38. Ca i, ca np, cng khi che lp mng bng sikhong hay bng khong. 8 78

Khng chy

39. Ca i, ca np, cng vi tm cnh g ph bng lp cc tng mng dy khng t hn 5mm, vi tn lp chng (xem ch thch 12)

3 4 5

72 78 90

Khng chy

40.Ca i vi tm cnh g c ngm tm chng chy hai mt g dn.

4 6

36 60

Kh chy

48-

Ch thch: 1) Gii hn chu la ca tng chu lc v tng ngn, c t panen trn lp

va lt mch, c xc nh theo s ch dn im 3, 4, 6 (ct danh mc kt cu) vi h s tnh ly theo ng sut trung bnh trong t hp ti trng tiu chun thng ng.

a) Tng theo im 3 dy qu 10cm khi ng sut: + 50 Kg/cm2 v nh hn - h s 1. + 70 Kg/cm2 - h s 0,7. + Ln hn 70 Kg/cm2 theo kt qu th nghim Khi xc nh gii hn chu la ca tng b tng ct thp ton khi dy ln hn

10cm, h s ch dn cao hn phi tng 20%. Khi gii hn chu la phi ly khng qu ch dn im 3.

b) Tng theo im 4a, khi ng sut: + 10 Kg/cm2 v nh hn - h s 1 + 20 Kg/cm2 v nh hn - h s 0,6 + Ln hn 20 Kg/cm2 - theo kt qu th nghim c) Tng theo im 4b khi ng sut: + 10 Kg/cm2 v nh hn h s 0,5 + Ln hn 20 Kg/cm2 - theo kt qu th nghim. d) Tng theo im 6 khi ng sut: + 30 Kg/cm2 v nh hn - h s 1 + 40 Kg/cm2 v nh hn h s 0,7 + Ln hn 40 Kg/cm2 - theo kt qu th nghim. 2) Bo v cc u mi gia c ca kt cu, phi bo m cng ca chng

trong sut thi gian bng tr s gii hn chu la yu cu ca kt cu; Gii hn chu la gia c thp khng c bo v, quy nh theo d kin kt cu, phi ly bng 30 pht;

3) Ch bt khe h cc v tr k cn ca tng kiu treo v tng t mang vi cc b phn ca nh, phi c gii hn chu la bng gii hn chu la ca tng;

4) Khi lm tng ngn bng khi xy thch cao rng, gii hn chu la ch dn im di y phi gim n 30%;

5) B dy ca tng ngn t khi xy dng keramzit rng, ch dn im di y, c xc nh nh tng b dy ca khi xy tng;

6) Gii hn chu la ca b tng nh, khi lng th tch 1.200 kg/m3 v ln hn, cng nh kt cu mt khu chu un lm bng b tng silict, phi ly nh i vi kt cu b tng ct thp;

7) Gii hn chu la ca kt cu b tng nh khi lng th tch nh hn v b tng ong, phi ly nh i vi b tng ct thp vi h s 1,3;

8) Gii hn chu la ca tm panen v tm b tng nhiu l c g pha bn, phi ly theo im trn vi h s 0,9;

9) Gii hn chu la ca tm panen theo im trn; ph thuc vo s tnh ton ca im ta phi ly:

+ Khi ta t do theo hai pha i nhau vi h s 1; + Khi tra theo ng vin c lin h cc pha: 1:1 vi h s 2,5 1:1,5 vi h s 1,3 1:1,5 vi h s 0,3

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2_3 Bien Phap PCCC Cho Cong Trinh(1)