TIU CHUN QUC GIA TCVN 9276 : 2012

SN PH BO V KT CU THP - HNG DN KIM TRA, GIM ST CHT LNG QU TRNH THI CNG

Protective paint systems for steel structures - Standard Guide for Painting Inspectors

Li ni u

TCVN 9276:2012 do Vin Khoa hc v Cng ngh Giao thng Vn ti bin son, B Giao thng Vn ti ngh, B Khoa hc v Cng ngh t chc thm nh v cng b

SN PH BO V KT CU THP - HNG DN KIM TRA, GIM ST CHT LNG QU TRNH THI CNG

Protective paint systems for steel structures - Standard Guide for Painting Inspectors

1. Phm vi p dng

1.1. Tiu chun ny a ra trnh t hng dn kim tra gim st qu trnh thi cng sn ph bo v kt cu thp.

1.2. Tiu chun ny a ra cc hng dn lin quan n cng tc x l b mt, thi cng sn, kim tra, gim st thi cng v chp thun nghim thu lp sn ph bo v kt cu thp.

2. Ti liu vin dn

Cc ti liu vin dn sau y l cn thit p dng tiu chun ny. i vi cc ti liu vin dn ghi nm cng b th p dng bn c nu. i vi cc ti liu vin dn khng ghi nm cng b th p dng phin bn mi nht, bao gm c cc sa i, b sung (nu c).

2.1. Tiu chun ASTM

ASTM D16, Standard Terminology for Paint, Related Coatings, Materials, and Applications Tiu chun thut ng cho sn, cc lp ph lin quan, cc vt liu v cc ng dng.

ASTM D1186, Test Methods for Nondestructive Measurement of Dry-Film Thickness of Nonmagnetic Coatings Applied to a Ferrous Base (Phng php o khng ph hy chiu dy mng kh ca lp ph khng nhim t c gia cng trn nn thp).

ASTM D1212, Test Methods for Measurement of Wet Film Thickness of Organic Coatings (Phng php o chiu dy mng t ca lp ph hu c).

ASTM D1400, Test Method for Nondestructive Measurement of Dry Film Thickness of Nonconductive Coatings Applied to a Nonferrous Base (Phng php o khng ph hy chiu dy mng sn kh ca lp ph cch in trn b mt khng cha st).

ASTM D 1475, Test Method for Density of Liquid Coatings, Inks, and Related Products (Phng php xc nh t trng ca sn lng, mc in, v cc sn phm lin quan).

ASTM D 1730, Practices for Preparation of Aluminum and Aluminum-Alloy Surfaces for Painting (Cc phng php chun b b mt nhm v hp kim nhm sn).

ASTM D 2092, Guide for Treatment of Zinc-Coated (galvanized) Steel Surfaces for Painting (Hng dn x l b mt thp m km sn).

ASTM D 2200, Pictorial Surface Preparation Standards for Painting Steel Surfaces (Tiu chun nh gi trc quan quy trnh chun b b mt theo hnh nh cho sn ln nn thp).

ASTM D 3359, Test Methods for Measuring Adhesion by Tape Test (Phng php kim tra bm dnh bng phng php bng dnh).

ASTM D 4138, Test Methods for Measurement of Dry Film Thickness of Protective Coating Systems by Destructive Means (Phng php xc nh chiu dy mng kh ca cc h thng lp ph bo v bng phng php ph hy).

ASTM D 4212, Test Method for Viscosity by Dip-Type Viscosity Cups (Phng php xc nh nht bng cc o nht Dip-Type).

ASTM D 4285, Test Method for Indicating Oil or Water in Compressed Air (Phng php xc nh du hoc nc trong kh nn).

ASTM D 4414, Practice for Measurement of Wet Film Thickness by Notch Gages - Quy trnh o dy mng t bng dng c n c vch chia n m ).

ASTM D 4417, Test Methods for Field Measurement of Surface Profile of Blast Cleaned Steel (Cc phng php xc nh hin trng b mt thp c lm sch bng phng php phun p lc).

ASTM D 4537, Guide for Establishing Procedures to Qualify and Certify Inspection Personnel for Coating Work in Nuclear Facilities (Hng dn quy trnh kim tra cht lng v chng ch t vn gim st cng vic sn trong lnh vc ht nhn).

ASTM D 4538, Terminology Relating to Protective Coatings and Lining Work for Power Generation Facilities (Thut ng lin quan n lp ph bo v v lp ph trong cng xng cho cc thit b pht in).

ASTM D 4541, Test Method for Pull-Off strength of Coatings Using Portable Adhesion Testers (Phng php xc nh bm dnh ca mng ph bng phng php ko tch (Pull-Off)).

ASTM D 5064, Practice for Conducting a Patch Test to Access Coating Compatibility (Quy trnh tin hnh th v kim tra s tng thch ca lp ph).

ASTM D 5162, Practice for Discontinuity (Holiday) Testing of Nonconductive Protective Coating on Metal Substrates (Quy trnh kim tra s bong rp ca mng ph bo v cch in trn nn kim loi).

ASTM D 6677, Test Method for Evaluating Adhesion by Knife (Phng php kim tra bm dnh bng dng c dao ct).

ASTM D 7091, Practice for Nondestructive Measurement of Dry Film Thickness of Nonmagnetic Coatings Applied to ferrous Metals and Nonmagnetic, Nonconductive Coatings Applied to ferrous Metals (Quy trnh o chiu dy mng sn kh trn nn thp v kim loi khng t tnh, sn cch in thi cng trn nn thp bng phng php khng ph hy).

2.2. Tiu chun qun l an ton lao ng v bo v sc khe (OSHA)

29 CFR 1926.59, Hazard Communication (Khuyn co thng tin an ton ha cht).

2.3. Tiu chun SSPC (Tiu chun ca Hip hi sn kt cu thp) SSPC-SP 1, Solvent Cleaning (Lm sch bng dung mi).

SSPC-SP 2, Hand Tool Cleaning (Lm sch bng dng c cm tay).

SSPC-SP 3, Power Tool Cleaning (Lm sch bng my).

SSPC-SP 5/NACE 1, White Melal Blast Cleaning (Lm sch bng phng php thi mnh t n b mt kim loi mu trng).

SSPC-SP 6/NACE 3, Commercial Blast Cleaning (Lm sch bng phng php thi va phi).

SSPC-SP 7/NACE 4, Brush-off Blast Cleaning (Lm sch bng phng php thi nh).

SSPC-SP 10/NACE 2, Near-White Blast Cleaning (Lm sch bng phng php thi mnh).

SSPC-SP 11, Power Tool Cleaning to Bare Metal (Lm sch bng my n mc kim loi trn).

SSPC-SP 12/NACE 5, Surface Preparation and Cleaning of Steel and Other Hard Materials by High- and Ultrahigh-Pressure Water Jetting Prior to Recoating (Chun b v lm sch b mt thp v vt liu cng khc bng tia nc p lc cao v rt cao trc khi sn ph li).

SSPC-SP 14/NACE No.8, Industrial Blast Cleaning (Lm sch bng phng php thi cng nghip).

SSPC-SP 15, Commercial Grade Power Tool Cleaner (Thit b s dng nng lng (in) loi thi va phi).

SSPC-PA 1, Shop Field and Manlanance Painting of Steel (Sn trong xng, ti hin trng v bo tr cho nn thp).

SSPC-PA 2, Measurement of Paint Thickness with Magnetic Gages (o chiu dy mng sn bng dng c t tnh).

SSPC-VIS 1, Guide and Reference Photographs for Steel Surfaces Prepared by Dry Abraisive Blasting (Hng dn v cc hnh nh so snh cho quy trnh chun b b mt thp bng phng php mi mn kh).

SSPC-VIS 1-89, Pictorial Surface Preparation Standards for Painting steel Surfaces (Tiu chun hnh nh v vic chun b b mt thp cho sn).

SSPC-VIS 3, Guide and Reference Photographs for Steel Surfaces Prepared by Hand and Power Tool Cleaning (Hng dn v cc hnh nh so snh cho quy trnh chun b b mt thp bng my v dng c cm tay).

SSPC-VIS 4/NACE No.7, Visual Standard for Steel Cleaned By Water Jetting. Tiu chun nh gi b mt thp lm sch bng phng php phun nc).

SSPC-Paint 27, Basic Zinc Chromate-Vinyl Butyral Wash Primer (Sn lt trn c s km Chromat - Vinyl Butyral).

SSPC-Guide 6, Guide for Containing Debris Generated During Paint Removal Operations (Hng dn thu gom mnh vn pht sinh trong qu trnh loi b mng sn c).

SSPC-Guide 7, Guide for Disposal of Lead Contaminate Surface Preparation Debris (Hng dn loi b cc mnh vn nhim bn kim loi Ch trong qu trnh chun b lm sch b mt).

2.4. Tiu chun ASTM b sung

Pictorial Surface Preparation Standards for Painting Steel Surfaces (Tiu chun nh gi trc quan vic chun b b mt thp cho thi cng sn trn nn thp).

2.5. Tiu chun TCVN

TCVN 8789:2011, Sn bo v kt cu thp Yu cu k thut v phng php th.

TCVN 8790:2011, Sn bo v kt cu thp - Quy trnh thi cng v nghim thu.

TCVN 2092:2008, Sn v vecni - Xc nh thi gian chy bng phu chy.

TCVN 2097:1993, Sn - Phng php xc nh bm dnh ca mng.

3. ngha v ng dng

3.1. Tiu chun ny cn c dng hng dn vic kim tra, gim st cht lng sn ph bo v. Mt s ni dung c th quy nh cho trng hp sn c bit (quy nh ti TCVN 8789:2011) c yu cu k thut p dng cho cc loi mng ph ging nh cc mng ph thng c s dng. Danh mc kim tra s dng trong lnh vc sn ny c quy nh ti Ph lc A.

4. Chun b kim tra

4.1. Tiu chun ny quy nh nhim v ca T vn gim st v a ra phng php kim tra (bng trc quan v bng thit b) kim sot cht lng thi cng sn theo cc yu cu k thut trong hp ng vi Nh thu sn.

4.2. Trc khi thi cng sn, T vn gim st cn phi nghin cu ch dn k thut ca d n, cc tiu chun k thut lin quan n loi sn, dung mi s dng, t l s dng, dy mng sn theo yu cu, lp sn lt, lp sn trung gian, lp sn ph ngoi, thi gian gia cc lp sn, x l b mt, phng php thi cng v cc khuyn co c bit cho php v iu kin mi trng xung quanh cng trng thi cng. Cc thng s chi tit ny phi c ghi li trong nht k thi cng trong sut qu trnh kim tra, gim st hn ch nhng hiu nhm gia T vn gim st v Nh thu.

4.3. T vn gim st phi lu bn photo v thng tin an ton ha cht ca tt c cc sn phm s dng, cc quy nh an ton khc c lin quan ti cng vic tham chiu vi cc yu cu ca nh thu theo tiu chun 29 CFR 1910.1200.

5. Phng php v yu cu chun b b mt

5.1. Chun b b mt kim loi sn l mt trong nhng cng on quan trng nht, nh hng ti cht lng ca mng sn. T vn gim st cn kim sot cht ch vic chun b b mt m bo vic thi cng sn t cht lng vi tui th xc nh.

5.1.1 Tiu chun hnh nh (atlat) ca ASTM D2200 hoc (SSPC - VIS1; SSPC-VIS 1-89) hoc TCVN 8790:2011 so snh gip cho T vn gim st trong qu trnh gim st lm sch b mt kt cu thp, kim tra mc x l b mt kt cu thp phi t c theo yu cu ca nh thu. Vi nhng d n ln, trc khi thi cng cn ly mt mu thp vi kch thc tng ng c x l b mt tha mn cc yu cu ca d n c th i chng trong qu trnh gim st. Mu thp x l b mt c bo v bi lp mng acrylic trong sut hay bc trong ti nha do trong sut bo v mu khi b g.

5.2. Cc yu t nh hng n cht lng mng sn

5.2.1. Lm sch

Phi loi b khi b mt thp cc tp cht nh du, m, vt bn, vt mi hn, vy thp... do chng lm gim tnh cht bm dnh ca mng sn ln b mt kim loi. Cn mui lng ng (clorit v sunfat) cng phi c loi b, nu khng s nh hng rt ln ti tui th (hoc bn) ca mng sn. Tiu chun TCVN 8790:2011 hoc Tiu chun SSPC lit k chi tit cc yu cu k thut x l b mt gm cc phng php lm sch nh ty bng dung mi, bng dng c cm tay hay thit b lm sch s dng nng lng (in) cng nh nhiu phng php lm sch khc.

5.2.2. nh g

Lp oxit mu xanh en l sn phm ca qu trnh cn nng, l nguyn nhn lm hng mng sn. Lp g ny kh gin v c th rn nt hay b bong ra khi thay i nhit (trong qu trnh gia cng kt cu thp v nh hng ca thi tit) dn n lm h hng mng sn.

5.2.3. nhm b mt

nhm ca b mt kim loi c nh hng ng k ti cht lng ca mng sn, n lm tng din tch tip xc gip mng sn bm dnh tt hn. Mc nhm b mt ph thuc c v loi v kch thc ca cht mi mn c s dng. Cc ht mi th thng to b mt th v su hn. Mt mi su tt hn s to iu kin sn bm dnh, nhng lng sn tiu th s nhiu hn ph kn b mt thp to nhm. Trng hp ny khng nn s dng loi sn c nht thp do khng ph kn c b mt thp to nhm, c khi s c ph bng mt vi lp sn ph ln trn. Chiu su rnh to nhm cn ln bng 1/4 n 1/3 dy mng ph trong h sn. Quy nh ny khng p dng c nu nhm b mt qu ln v khi s xut hin s to gc v mt ca b mt nhm c th nh hng n bm dnh ca mng sn. Cch xc nh nhm b mt c hng dn ti ASTM D 4417 hoc TCVN 8790:2011.

5.3. Cc phng php lm sch

Qu trnh lm sch khng quy nh ring cho tng phng php lm sch. Cc quy nh v dung mi v hp cht lm sch do Nh sn xut cung cp phi thng xuyn thay i m bo bo v sc khe cho ngi lao ng.

5.3.1. Lm sch bng phng php ha hc

Cc dung mi thng c dng ty sch du m v cc vt liu khc c tnh cht tng t. Dung mi cn li trn b mt c lm sch bng cch lau chi bng bn chi hay gi lau. Cht bn c loi b bng cch lau cn thn cc vng b nh hng vi vi thm dung mi, vi bn khng c nhng li vo dung mi. Qu trnh lm sch c th c lp li bng vi sch v dung mi mi. Nh tng, hp cht ty ra, lm sch bng kh nn hay cc phng php v vt liu tng t cng c th c s dng. Khi dng cht lm sch dng nh tng, x phng, hay thuc ty, s c hiu qu cao hn nu dng vi nc sch, nng. Tiu chun SSPC SP-1 hoc TCVN 8790:2011 bao gm c phng php dng cc cht ny.

5.3.1.1. Lm sch bng hi dung mi

Phng php ny thch hp vi c dy chuyn sn xut hay h thng hot ng lin tc. Lm sch bng hi loi b tt c cc cht bn ha tan nhng khng th loi b lp oxit t nhin. Nu lp ny phi loi b cn s dng phng php lm sch c hc. Phi lm sch vng hi dung mi ngng t trn b mt kim loi. Ty nhn bng hi dung mi khng loi b c cc ht vt liu, nhng v tr nn dng gi - lau loi b cc ht khng tan. Ty nhn bng hi dung mi thun tin hn lau bng dung mi v khi dng dung mi nng th s ngng t ca dung mi s dng s khng lm b mt b bn li.

5.3.2. Lm sch bng dng c cm tay

Phng php ny dng loi b cc lp g lin kt lng lo, g st, cc mng sn c, mi hn chy, ht g st trn mt kim loi khi chi bng tay, nh bng ct, co bng dy kim loi, bn chi lng cng, giy rp, bi thp hay c bng ba. Vt liu c xem nh bm dnh cht nu khng b tch khi b mt khi lm sch bng dao trt. Tiu chun SSPC (SSPC- SP2), TCVN 8790:2011 hoc cc tiu chun tng t quy nh chi tit v vn ny. Tiu chun quan st SSPC-VIS 3 c s dng h tr vic xc nh tnh chnh xc ca qu trnh lm sch.

5.3.2.1. Lm sch bng dng c cm tay yu cu tt c x hn, nha ng, du m v cn bn dng du m khc phi c loi b trc bng dung mi.

5.3.2.2. Bn chi thp phi cng lm sch hon ton b mt v c hnh dng thch hp c th xm nhp, lm sch c mi gc cnh v khp ni. Bn chi phi c gi sch trnh cc vt liu bm vo b mt bn chi gy cn tr qu trnh lm sch.

5.3.2.3. Dng c dng co cm tay phi c lm bng thp, c ti v gi c cnh sc, phi c kch thc thch hp v hnh dng thun li cho vic lm sch. Dng c co lun lun phi gi c sc ca li.

5.3.3. Lm sch bng my

Phng php ny s dng lm sch cc ba via lin kt lng lo, g st, sn hng v cc mi hn trn b mt kim loi nh cc bn chi dng in, dng c s dng nng lng, my mi, my phun ct, hay kt hp cc phng php trn. Vt liu c xem nh bm dnh cht nu n khng th tch ra bng dao trt. SSPC-SP 3 c cc c im chi tit cho thit b lm sch bng in. Tham kho Tiu chun SSPC-VIS 3 a ra la chn thch hp.

5.3.3.1. Khi s dng thit b lm sch bng nng lng (in) yu cu tt c du m, mi hn v cc cht bn khc phi c loi b trc bng dung mi. Lm sch bng dng c cm tay theo 5.3.2 c s dng ph hp trc khi lm sch bng my (thit b lm sch bng nng lng in).

5.3.3.2. Tt c cc ph kin phi thch hp vi loi hnh dng vt cn lm sch v gi sch trnh cn tr qu trnh chi hay lm mt hiu qu hot ng ca thit b. Tt c cc v tr va chm u phi gi c sc.

5.3.4. Lm sch kim loi trn bng thit b s dng nng lng (in).

Phng php ny dng lm sch ton b sn ph, g v g vy.... Thit b lm sch s dng nng lng (in) bao gm: cc bnh v a mi mn, a ph lp mi hay giy rp, bnh ph lp mi v bng mi. SSPC-SP11 m t chi tit cc c im khi lm sch b mt kim loi trn bng thit b| s dng nng lng (in).

5.3.4.1. Ph thuc vo iu kin ban u ca b mt v iu kin mt ct hin c, c th cn 1 hoc c hai loi thit b in. Tt c du m, mi hn v cht bn khc phi loi b trc bng dung mi (phng php 5.3.1), lm sch bng dng c cm tay (5.3.2) hay lm sch bng thit b s dng nng lng (in) (5.3.3) trc khi lm sch kim loi trn bng thit b s dng nng lng (in) theo phng php trn (5.3.4)

5.3.4.2. Tt c cc ph kin phi thch hp vi loi hnh dng vt cn lm sch v gi sch trnh lm cn tr qu trnh chi hay lm mt hiu qu hot ng ca thit b. Sng phun kim yu cu ng knh l kim 2mm to ra hnh dng b mt thch hp.

5.3.4.3. B mt cui cng phi l kim loi trn, sng. Phn mng cn li ca g hay sn ph c th cn li trong cc l (nu nh b mt c cc l). SSPC VIS 3 l tiu chun so snh cho trng hp ny. B mt c quyt nh bi cc qu trnh quy nh ti 6.1.1.

5.3.4.4. Lm sch bng thit b nng lng (in) loi thi va phi, tiu chun SSPC-SP15 c s dng tng t vi tiu chun SSPC-SP 11. B mt sau khi lm sch phi c mu sng trng ca kim loi trn. Vic lm sch cho php t l phn trm dung tch g im v lp sn mng cn li t 33 % so vi din tch theo tnh ton ban u, nu b mt sn ban u b g im.

5.3.5. Lm sch bng phun ct

Phng php ny s dng lm sch sn ph, g v cc g cn thp trn b mt kim loi v to cho b mt kim loi tr nn th rp bng cch s dng thit b phun p lc phun cc ht mi nh, cng nh ct kh, mt hay bi thp ln b mt cn lm sch.

5.3.5.1. Phng php ny s dng kh nn, u phun c bit v ht mi. C th a nc vo trong dng kh gim bi. Cc phng php khc s dng ch yu trong cc cng xng ch to, cc

bnh y to ra lc ly tm y cc ht mi vo vt liu. Kch thc ln nht v nh nht ca ht mi s nh hng n nhm b mt.

5.3.5.2. B mt phi c lm sch du m, mui hn bng dung mi trc khi phun ct. Thit b phun ct c trang b b lc loi b nc ngng t hay du. Kim tra khng kh nn theo hng dn ti ASTM D 4285 hoc TCVN 8790:2011.

5.3.5.3. H thng phun ct cn c thc hin sao cho phn nn ca b mt khng b ph hy. Phun ct thng c thc hin t trn xung di ca cu trc v ch nn thc hin thun chiu gi trong cc vng c sn. H thng phun ct kh khng thc hin cc b mt sau khi phun ct b m. Nhit b mt thp cn phi ln hn im sng t nht 3 oC.

5.3.5.4. Hiu qu ca phng php phun ct theo yu cu k thut x l b mt v tun theo tiu chun nh (atlat). Tiu chun ca ASTM, SSPC, TCVN 8790:2011 v Hip hi quc t v K thut n mn (NACE) c a ra bng di. Ch Tiu chun x l b mt m t ASTM-D 2200 c chia lm 2 phng php. Phng php A gii thch tiu chun trn nh theo ISO Pictorial Surface Preparation Standards - tiu chun kim tra quy trnh chun b b mt theo phng php so nh trc quan. Phng php B gii thch tiu chun trn nh theo SSPC. Hai b nh ny khng c so snh trc tip (v chng khng tng ng).

Bng 1 - So snh cc tiu chun lm sch b mt.

Hng dn x l SSPC TCVN 8790(*) ASTM D2200

NACE Phng php AA

Phng php BB

Lm sch bng phng php thi mnh t n b mt kim loi mu trng

SSPC-SP5 Sa3 Sa 3 SP5 1

Lm sch bng phng php thi mnh SSPC -SP10 Sa 2

12 Sa 212 SP10 2

Lm sch bng phng php thi va phi SSPC - SP6 Sa 2 Sa 2C SP6 3

Lm sch bng phng php thi nh SSPC - SP7 Sa 1 Sa 1 SP 7 4

Lm sch bng phng php thi cng nghip SSPC-SP14 - - - 8

CH THCH 1:

(*) TCVN 8790: Mc 4.3.2 - Lm sch bng cht mi mn kh;

A Phng php A l tiu chun ISO/Thy in;

B Phng php B l tiu chun SSPC-VIS-1;

C Tiu chun kim tra trc quan sch Sa 2 l khng tng ng vi nh ngha trong tiu chun SSPC (SP6) v sch thi va phi.

5.3.5.5. Kim sot k nhng vt bn du m hay bt k vt bn no trn b mt trc khi phun. Khi phun ct, tt c cc cht bn phi c loi b bng dung mi (xem ti 5.3.1). B mt c phun phi kh, c chi vi bn chi sch, thi vi khng kh kh khng c du v hi m, hay lm sch bng ht chn khng lm sch tt c cc bi bn do qu trnh thi cn lu li trn b mt ng thi lm sch nhng v tr gc cnh m thit b phun ct khng x l c.

5.3.5.6. B mt sau khi lm sch bng phun ct phi c sn lt ngay trong ngy, thch hp nht l trong khong thi gian 8 h sau khi phun ct lm sch, hoc trc khi cha c bt k vt g no xut hin. Nu xut hin g hoa trn b mt th phi phun ct lm sch li.

5.3.6. Lm sch bng phun nc p lc cao: cn s dng nc sch, c hoc khng c ht mi mn, c s dng xen k nhau phun vi mc ch gim thiu lng bi vo khng kh. p sut vi phun phi ln hn 137900 KPa c th loi b ton b lp sn c nu nh ch dng nc. Vic phun nc p sut cao khng kt hp ht mi mn khng th loi b via cn hay cc b mt thp c

nhm thp gn cht. B mt phi kh hay c lm kh trc khi sn. Tiu chun SSPC SP-12/NACE 5 a ra cc nh ngha v cc mc sch c th khi s dng nc p lc cao. Tiu chun SSPC-VIS 4/NACE No.7 nh gi b mt thp lm sch bng phng php phun nc.

5.4. Lm sch v x l cc b mt khc nhau

Trc khi thi cng vi bt k loi sn no th b mt u phi lm sch v chun b cho ph hp vi yu cu k thut. Tt c bi, cht bn, du m, hi m, mui than, sn c v cc cht bn khc phi c lm sch. Cc git xi mng hay va trn b mt trc khi sa cha phi c lm sch bng c hc hay ha hc. Cc ba via ra hay bt k nhng g gy tr ngi cho kt cu u phi ct b.

5.4.1. B mt thp

Loi b g v ba via cng c thc hin bng cc phng thc nu trn l lm sch bng tay, my hay phun ct.

5.4.1.1. B mt c kt cu phc tp, tt c cht bn v cc mnh vn phi b loi b khi cc v tr nh: cc hc, cc ng nt, cc v tr mi ni, khp ni, pha trn b mt ngang... cc mnh vn nm cht ng trn b mt ngang ca kt cu cn loi b. c bit ch ti cc v tr kh kim tra nh vng nh, mt sau ca ai c hay bulong, mt di ca chi tit kt cu

5.4.2. B mt m km

B mt c ph lp m km cn c lm sch v x l theo hng dn trong tiu chun ASTM D 2092. Mt khc, b mt c th c trong thi tit t nht 6 thng trc khi lm sch v sn.

5.4.3. B mt nhm

5.4.3.1. Lm sch hon ton du m khi b mt nhm l rt quan trng. Lm sch du m bng hi hay nhng trong dung dch lm sch bng kim hoc axit thng c s dng trong cng xng. Ti cng trng, vic lm sch bng nc tip theo bng dung mi, hi hay thuc ty l ph hp.

5.4.3.2. Lp sn lt vinyl l mt trong cc phng php x l li kim loi thng s dng i vi nhm khng anot ha. Cc vt liu c a ra trong ASTM D1730, Loi B, Phng php 8 v trong SSPC cho sn 27-sn lt trn c s crommat km. Bt mu trong sn lt c cha ch khng bao gi c s dng trn b mt nhm. X l nhm t nht l Loi B, phng php 3 ca ASTM D 1730, a ra phng php s dng cht lm sch l axit photphoric alcol ha.

5.4.4. Khuyn co trong x l b mt cha sn v b mt sn

Lm sch nn thc hin theo tng vng, tng hay tng phn trn b mt. Lm sch dt im, kim tra k v phi c nghim thu trc khi sn. Ch dn k thut cn c gii hn da trn t l vng c lm sch v vng sn trong cng thi im, vic thc hin xen k lm sch v sn ti cc vng nh thng khng tt, iu ny c th dn ti lm bn b mt v cc vng sn c lin quan.

5.4.4.1. Nu lng bi (do bt k nguyn nhn no) c t l cao c th x l bng cch s dng cun giy tm nha ng cho khong cch xung quanh kt cu v m bo cc phng n d phng cn thit khc bo v khi bi v cht bn nh hng n b mt lm sch hay b mt mi c sn; khi cng cn lm sch b mt mi sn ph bng cc phng php c bit gia cc ln sn.

5.4.4.2. Mt s v tr c sn hoc sn li c th nm trong vng hi ha cht, nu cn thit c th phi c ra sch bng nc trc khi sn. Vic ra sch cng cn thit gia cc lp sn chng ln nhau.

5.4.4.3. Cc cht bn nm trong cc hc, l trn b mt thp cn c loi b. Mui clorua t cc mun tan hay trong mi trng bin, v mui sunfat trong khng kh khi b mt kim loi b nhim c th lm gim tnh cht ca sn ph. Bng phng php phun nc p lc cao c dng loi b cc cht bn ny.

5.4.4.4. Quy nh cn yu cu thu gom cc mnh vn t vic chun b b mt a i x l. Khi cc lp sn c bin tnh vi cc kim loi nng nh ch hay crom, hay cc cht khc nh cht chng ru mc th vic x l cc mnh vn l cn thit. S xem xt rc thi t qu trnh thi cng, c bit l cng vic bo qun v x l chng cng l mt phn trong cng vic ca ngi gim st sn, SSPC ch dn 6 v 7 cung cp cc thng tin hu ch cho ngi gim st. Trong qu trnh loi b ch, ngi gim st cn phi hiu bit v cc yu cu OSHA i vi sc khe v s an ton cho bn thn.

5.5. Kim tra b mt trc khi sn ngoi hin trng

5.5.1. Cng trnh xy dng mi

Cn phi khng nh rng lp sn ph u tin phi c sn ln b mt c lm sch trc khi vt bn hay hin tng g xut hin. Nu sn ngoi tri, vng lm sch cn phi c che chn bo v tt trc khi tri ti do gim nhit v tng hi m v ban m c th gy ngng t nc ln b mt kim loi. Khi sn v lm sch b mt c thc hin trong nh xng, c th cho php vic sn ph sang ngy hm sau nu b mt c lm sch bng phun ct.

5.5.1.1. B mt thp ph sn khi vn chuyn ti cng trng xy dng cn phi bo qun trnh tip xc vi mt t, trnh b hoen , try xc v t chu nh hng xu ca du m, mui. Trong thc t, thp phi c bo qun trnh hnh thnh cc ti gi nc. Nu gi ngoi tri trong thi gian di (vi thng), ngi gim st nn kim tra cht lng ca mng sn theo thi gian m bo cc khuyn tt c sa cha theo quy nh trong hp ng. Khong thi gian t khi sn lp lt trong cng xng n khi lp rp v tin hnh sn lp ph tip theo nn duy tr trong thi gian ngn nht ngn nga s khng bm dnh ca cc lp ph bn trong.

5.5.1.2. Trc khi sn ph lp u tin, b mt phi c lm sch bi, nu cn thit phi loi b cc cht bn du m, c th bng lau chi, lm sch bng kh nn, ty ra bng my vi cht ty ra hoc lm sch bng dung mi c chn la ph hp khng lm mm mng ph. Cc vt xc v v trn b mt, bao gm c cc vt xc do hn, bt bu lng, inh tn, cn c lm sch, sa theo quy nh trc khi sn ph ln b mt thp.

5.5.1.3. Ngi gim st phi m bo cc ba via ca inh tn phi c lm sch vy st v vt hn. im quan trng l tt c mng sn ca h phi c sn trn b mt kh, khng c vt bn, v cc lp ph c khng b ph hy c hc. Cn ch khng lm ng mui gy g di hoc gia 2 lp sn ph.

5.5.1.4. Ngi gim st phi xc nh cc c im k thut cng vi cc ti liu tham kho cho php sn hoc khng cho php sn ln cc b mt tip xc khi bt vt hoc inh tn vo kt cu. Ngi gim st phi m bo c s lng cc lp sn ph theo quy nh trc khi chuyn sang hng mc khc.

5.5.2. Sn trong qu trnh bo dng, sa cha

Trong hu ht trng hp, vic bo dng sn li bao gm vic lm sch ti ch v khoanh vng khu vc b hng, sau to mt lp ph mi cho ton b b mt kt cu. Ngi gim st qu trnh bo dng cn ch ti mt vi iu kin c th ny sinh trong qu trnh nh sau:

5.5.2.1. Mng sn tt ln cn khu vc sn b hng khng b ph hy khi lm sch lp sn hng. iu ny c bit quan trng khi lm sch bng phun ct. 5.5.2.2. Khu vc tip gip gia vng mng sn tt v vng khoanh vng lm sch cn phi lm nhn. Khi thi cng sn n vng tip gip nn ph chng ln lp sn c, lp sn lin k ph rng m bo ph kn ton b din tch khoanh vng lm sch. Cn phi lm sch khu vc ny. Khi sn ph ln khu vc lm sch cn phi ph chng ln lp sn c m bo phm vi ca khu vc cn sn ph. Trc khi hon thnh tng th cc lp sn sn cc lp sn ph ton b b mt, ngi gim st cn khng nh m bo du m, cc vt bn, bi v cc vt cht bn khc phi c lm sch khi lp sn c.

5.5.2.3. Kh nng bm dnh ca lp ph mi vi lp c cn c kim tra cn thn. Vic nh gi cht lng lp ph bo dng c hng dn ti ASTM D 5064.

5.5.2.4. Di s hng dn ca thit k, t vn gim st, th vic gim st c th kim tra di lp b mt lp ph c hoc mi kim tra g, hoc s dnh bm ca lp ph c v nu khng m bo yu cu, b mt phi c x l v sn li.

5.5.2.5. nh hng ca lp ph mi trn lp ph c cn c ch nh sau: Bt k lp ph no cho thy s qun, rp hay nhn phi c bo co vi k s thit k cc v tr phi sn li. Nu cc khuyt im phm vi rng (khng phi mt vi v tr c lp) cn thay i loi sn khc.

6. Bo qun v x l sn

6.1. Bo qun sn v dung mi

Tt c cc loi sn v dung mi pha long cn phi c bo qun trong khu vc thong kh v khng c kh nng pht nhit, bt la, chp in, hay trc tip di nh sng mt tri. Kho bo qun phi t tiu chun s dng v thc hin theo vn bn ti liu hng dn ca Nh sn xut. Sn rt

nhy cm vi cc tc ng ca nhit bo qun nh cn trnh bo qun trong kho nhit bng gi hoc nhit qu cao s lm gim thi gian sng ca sn. Vt liu thng b ph hy nhit thp nn cn gi nhit khng ng bng. Nhit qu cao s lm gim thi gian sng (thi hn lu kho hoc thi hn s dng) ca sn. Nu sn phi gi trong 1 mt khong thi gian di vi lng ln, th hng thng cn phi lt ngc thng cha. Vic ny lm gim hin tng sa lng cng nh lm hn hp c trn u d dng hn khi dng.

6.1.1. Thng cha sn v cht pha long phi m bo khng m ti khi s dng v thng c nht phi dng u tin. Hng dn s dng ca Nh sn xut s a ra cc ch tiu lin quan ti tui th thi hn s dng ca sn. Mng ph ph thuc vo cc nh hng xu khc trong sut qu trnh bo qun khi cha s dng sn b chuyn sang mu nu sm, b gel ha hoc cc bin i tnh cht khc trong (b hng) qu trnh lu gi sn th khng nn s dng. Nu nguyn nhn bin i tnh cht sn. Nu mt vt liu cha xc nh c chnh xc, khng c s dng cho ti khi c kim tra bi Nh sn xut hoc phng th nghim c lp v tm ra kt qu.

6.1.2. Khi trong thng cha hnh thnh lp mng bao ph, lp mng ny c th nn c loi b. Nu cm nhn thy lp ph ny qu dy v c nh hng ti kt cu, sn cn li trong thng khng nn s dng c dng cho ti khi c kim tra v c kt lun chnh thc cho php dng hay khng.

6.2. Pha trn sn

Sn cn c trn u trong thng cha sch trc khi s dng dng. t ng nht, c th trn bng my hay bng tay, ton b vt liu phi c vo thng cha sch. Bt mu sau c ha trn t y trong thng vi cnh khuy mi cho sch, tit din phng, bt mu dng cc s c b p ph v v trn u trong hn hp. Sn lng c a t t vo thng cha ng thi c khuy trn, iu ny cng hu ch khi trn hay rt lin tc t mt thng cha khc cho ti khi hn hp tr nn ng nht. y ca thng cha cn c kim tra hin tng bt mu cn lng ng. Sn 2 hai thnh phn cn c pha trn bng dng c khuy trn trong thng cha tng thnh phn ring n ng nht. Sau khi cc thnh phn ng nht, chng c pha trn bng cch khuy trn theo t l v quy trnh hng dn ca Nh sn xut, l a phn B vo phn A. Sn lng khng nn pha trn hay gi dng huyn ph bi c th to bt kh di mt ca lp ph.

6.2.1. Mt s mng ph yu cu lc sau khi pha trn, m bo s ng nht v loi b lp bc cng nh cc vt liu ngoi. Li lc phi c loi c kh nng loi b lp v mng trn mt v khng gi li bt mu trn li lc. V d, li lc 297 m thng c dng cho hu ht cc loi sn, tr mt s loi c bit c yu cu theo ch dn k thut. Thng cha phi c y np khi khng s dng trnh h thng hao ht do bay hi dung mi v to thnh lp mng trn mt.

6.2.2. Cht to mng cn phi c khuy trn cho ti khi m bo ng nht, mt s vt liu yu cu khuy trn ngay c trong qu trnh s dng.

6.3. Pha long

Mt s yu cu k thut cho php pha long cht to mng trong phng th nghim trong khi mt s khc th khng, y l qu trnh thng dng khi pha long cht to mng.

6.3.1. Mu ban u

Khi c php tin hnh pha long ti v tr lm vic (V d: dung mi t trong cc thng cha cha m v km theo hng dn s dng ca Nh sn xut), ngi gim st phi gi t nht 1 lt mu cho mt phng th nghim (ng gim nh) t mi l dung mi cng vi 1 lt mu dung mi c s dng, ng ring bit trong hai hp. Yu cu c gi i cng vi mu c cung cp ch dn v t l pha long thch hp cho lp ph.

6.3.2. Pha long sn

Tt c cc ph gia thm vo dung mi pha long phi c thc hin vi s c mt ca ngi gim st v ch mt t l hoc loi dung mi c cho php ph hp vi tiu chun k thut hay ch dn ca Nh sn xut, hoc c hai mi c thm vo. Pha long c thc hin bng cch khong mt na sn c trn k vo thng cha sch. Dung mi ph hp yu cu c thm vo v hai phn c ha trn cho ti khi to thnh hn hp ng nht.

6.3.3. Th mu sn pha long

Trong qu trnh lm vic, mu sn pha long khng cn phi kim nh tr khi xut hin s khng ng nht ca lp ph hoc nghi ng c s thay i trong cht pha long.

6.3.3.1. Khi ngi gim st kim tra cht lng sn v c thit b cn thit trong vn phng, vic kim tra c th thc hin ngay ti ch i vi qu trnh pha long v sn pha long. Tin pha long c th chp nhn. Ngi gim st cn phi gi bn ghi nh v ton b qu trnh iu chnh sn, t l pha long, trng lng trn 1 galon ( M bng 3,78 lt, Anh bng 4,54 lt) v nht. Khi mng ph kh c dy t yu cu, ngi gim st phi xc minh dy cn thit i vi mng t to ra c mng kh c dy mong mun vi sn pha long. Gim st vin phi thng xuyn kim tra dy mng t theo tin trnh cng vic vi sn pha long. Tuy nhin, ph hp vi yu cu k thut phi da trn c s chiu dy mng sn kh c quy nh.

6.3.3.2. c lng dy mng t ca cht to mng pha long theo yu cu to ra mng kh c dy quy nh, cn phi bit c gi tr phn trm th tch ca cht rn (khng bay hi) trong cht to mng ban u. Nh sn xut phi cung cp s liu ny. Vic tnh ton dy mng t c thc hin theo cng thc sau:

(1)

Trong :

W dy mng t, m ;

D dy mng kh theo yu cu, m ;

S phn trm th tch ca cht rn trong mng, %;

T phn trm theo th tch ca dung mi pha long thm vo, %.

6.4. Gia nhit vt liu sn

Sn khi c nh sn xut giao trong thng cha ca nh sn xut v c trn cn thn l c th s dng tr khi yu cu k thut cho php pha long ngay ti ch cc vt liu c nht qu cao. Khi nhit ca sn thp (di 10oC) nht c th tng nn vic thi cng rt kh khn. Khi khng c php pha long, cht to mng phi c gia nhit. Nh thu mong mun gim nht bng cch gia nhit, thi cng d dng hn, thc hin c th lm nng thng cha trong nc nng, trong b tn nhit hi nc, gi trong phng m, hay bi mt s qu trnh gia nhit gin tip khc c chp thun. Cc my si km theo cng c s dng cho cc thit b gia nhit. Khng c dng chn la lm nng thng cha sn. Cn lu n nhit ca thng sn khi gia nhit trnh thp hn nhit ti thiu trong trng hp khi thi cng nhit mi trng thp, sn d b mt nhit do nh hng ca nhit mi trng v nhit b mt thp.

7. Xem xt iu kin v thi tit

7.1. Qu trnh kh mng sn

Cn ch l hu ht cc loi sn ph, c bit trong cng trnh xy dng, s khng kh hon ton nhit thp v m cao v cng khng th c mng sn tt khi gia cng trn b mt m (tr loi sn c bit c kh nng ng rn trong iu kin m).

7.2. Nhit thp

Rt nhiu c im k thut cho thy nhit gii hn ti vic sn ph c th thc hin c. Nhit thp nht thng thng (khng kh, vt liu, b mt..) l 5oC, nhng c th thp nh -18oC cho sn ng rn ngui mt hoc hai thnh phn, hay 10oC cho sn 2 thnh phn thng thng. Nhng yu cu cho thy rng khng th thc hin sn khi nhit gim xung ti 3oC hoc thp hn. Tuy nhin, mt vi kin cho rng mt s sn ph c th thc hin nhit 0oC hoc thp hn m khng b nh hng. C nhng gii hn cho thnh phn ca sn ph thuc vo loi sn v qu trnh lm kh b mt. Sn trn bng hay sng s lm cho sn khng bm dnh c.

7.3. Nhit cao

Nhit cao nht cho b mt l 50oC tr mt s trng hp c bit. B mt qu nng s lm cho dung mi sn bay hi qu nhanh dn n gia cng kh khn, phng rp hay xp mng sn. nhit gim xung c th thc hin sn di mi che hoc sn trn b mt c ph bt trnh nh nng hoc sn theo lch trnh trnh ma v v nhng ngy nhit cao.

7.4. m

Sn khng th thi cng di tri ma, tuyt, hay sng m, hoc khi nhit di 3oC. c bit trong nhng ngy ma xun v ma thu khi ban ngy m cn ban m mt. B mt t khng th sn c tr trng hp sn c thit k loi sn c th thi cng trn b mt m t. m tng i ca khng kh gii hn nh hn hoc bng 85%. m cao thng c nh hng ti qu trnh ng rn ca mng sn. Nu nghi ng m v nhit dn n m trn b mt c sn, cn o m v im sng theo hng dn ti 10.2.1.2.

7.4.1. Khi sn ph lc tri m t hoc lnh, b mt c sn di mi che hay c bo v khi b tc ng bi khng kh xung quanh v thp c lm nng ti nhit thc hin. Thp c thi cng di mi che cho ti khi sn ph kh hoc ti khi iu kin mi trng cho php.

7.4.2. Mng sn mi thi cng s khng tt i vi trng hp nhit mi trng nm nhit im sng (nhit ng bng), m cao, ma, tuyt hay nc ngng t. Khi , b mt sn cn x l v sn li b mt vi s lng lp mng ging nh vng khng b ph hy.

7.5. Gi

Hng gi v tc gi cn c xem xt khi sn ph trong vng c khng kh lu thng c th dn ti lm hng t, tu thuyn hay cc cng trnh gn . Gi mnh lm cho mng sn b bin i ng k v dn n s kh qu mc ca cc git trn b mt. Kt qu ny lm mt kh nng lin kt ca mng (phun kh). Nu khng x l, phun kh dn n cc khuyt tt lm gim hiu sut mng sn, v lm gim kh nng bm dnh ca cc mng c thi cng hay cc lp sn khc. Dung mi vi bay hi thp hn c th lm gim hay loi b hin tng phun kh v to ra b mt mn hn. Cc vn c th loi tr bng cch dng phng php qut hay ln thay th cho phun hoc lm vic vo lc c t gi, thay i vt liu thnh loi kh nhanh hn khng lm nh hng n cc b mt ln cn, c th thay i lch thi cng i khi gi thi theo hng khc mng sn phun kh b ph hy.

8. Thi cng mng sn

8.1. Cht nhim cn d

Phi kim tra trc quan b mt ca lp sn khng nh cc x do mi, bi bay mnh v hon ton b loi b. Vic loi b bi trn b mt chun b thi cng cn phi xem xt cn thn, khi quan st khong cch 1 m, khng thy r ng vch xut hin khi qut bng gng tay trn b mt l t yu cu. Trong qu trnh kim tra, cng phi m bo du m hay cc cht bn gc du m phi b loi b hon ton. C th dung mi, hi nc hay cht ty ra theo tiu chun SSPC-SP1, hoc TCVN 8790:2011.

8.2. m bo cht lng

T vn gim st cn phi tham kho cc d liu sn phm ca Nh sn xut v m bo rng:

- Mng sn phi p ng ging nh m t trong yu cu k thut;

- Sn c th c ha trn hoc pha long (nu cho php);

- Mu sc ph hp theo mu tiu chun cung cp;

- C cc d phng hp l phng nga ph hy ti cc vng ln cn trong khi x l b mt hay sn;

- Thc hin cng vic phi c tnh ton trc sao cho vic ph hy cc mng sn mi mc nh nht;

- Cc trang thit b thi cng (chi qut, phun) c chp nhn theo loi, sch v kh nng s dng;

- iu kin thi tit c chp nhn theo yu cu trong c im k thut;

- Thit b kim tra tha mn yu cu k thut v m bo phi sn sng s dng;

- Ch s dng cc phng php kim tra c quy nh ti 8.3 8.7. Tiu chun SSPC-PA 1, TCVN 8790:2011 hoc cc tiu chun tng t l nhng quy nh k thut cho thi cng mng sn.

8.2.1. Khuyt tt mng sn

Tt c cc mng sn ph phi c b mt tng i mn, khng to cc, tng do phun qu kh, qu dy, mng sn khng to nn cc dng khuyt tt nh: v cam, mt c, l, bong bng hay cc khuyt tt khc. Nhng v tr mng sn b dy ra ngoi, khng , ngt qung hay b st u khng c

chp nhn. B mt chy v lm c gii quyt bng cch qut u hoc ch nhm nu nh mng sn ng rn. Bi, cc x do mi hoc cc mnh vn khc b gn vo mng sn phi loi b trc khi ph tip mng sn mi.

8.3. Thi cng bng phng php qut

Phi s dng th sn c tay ngh cao khi thi cng lp sn ph bng phng php qut to ra mng sn mn v c dy ng nht. Sn t v tr kh ti v tr m, ph mng sn ln b mt v lp li trn phn t ca vt qut trc . Mng sn c qut trn tt c cc v tr khc ca b mt, ch nt v cc gc. Nhng v tr mng sn b chy, lm phi c qut li. B mt khng th sn c bng phng php qut thng thng v khng c qut phun th c th thc hin bng cch qut vi tc nhanh. Thit k k thut c th yu cu thi cng sn theo kiu to lp ph sc to ra dy mng sn y ti cc v tr d b hng. Cc cnh v gc ca chi tit kim loi, u ai c, bulong. v tt c cc chi tit khc, cc thanh, khi v mt c th c sn sc bng phng php qut s li th hn so vi cc phn khc trong qu trnh thi cng sn.

8.3.1. Chi qut c th t cht lng tt vi kh nng d un ca si lng mm to s tng thch vi lp ph, v c kch thc thch hp vi cc vng phi sn. Chng thng khng vt qu 100 mm chiu ngang v si lng khng di qu 90 mm. Chi qut phi c gi sch iu kin thch hp khi khng s dng. Ngi gim st c quyn khng cho s dng cc chi qut nu khng c gi iu kin cho php.

9. Thi cng bng phng php phun

Phng php phun c th c php p dng hoc khng. Thng thng phng php ny c s dng trong cc cng xng ch to, nhng v n c th lm hng cc vt xung quanh nn khng c chp nhn trng hp ny. Ngi gim st cn phi hiu r v cc phng php phun sn khc nhau, c th phun bng khng kh nn, phun khng c khng kh, phun p lc ln, phun tnh in v phun th tch lp p sut thp.

9.4.1. Trang thit b phi thch hp cho mc ch s dng, phun ng cch v s dng p lc thch hp vi tng loi sn. Trang thit b phi c gi trong iu kin sch s m bo khi thi cng sn khng to bi, sn khng b hng do kh hay cc tp cht khc trong mng sn. Ngun cung cp khng kh phi khng c hi m v du. C th xc nh thng qua vic s dng giy thm trng theo hng dn ti ASTM D 4285. Thit b phun khng c khng kh phi c khu vc thi cng hp l. Bt k lng dung mi no cn d trong thit b u phi c loi b hon ton trc khi sn.

9.4.2. Cc thnh phn sn phi c gi dng hn hp trong bnh phun hay thng cha trong sut qu trnh phun, c khuy trn c hc lin tc hoc gin on. Mng ph cn c gia cng thnh lp ng nht, c s chng cho cc ria. Cc thnh phn iu chnh sao cho mng sn phun m bo thng nht. Trong qu trnh phun, sng phun phi t (vung gc) vi b mt v khong cch m bo lp sn t bm c ln b mt. Ngng bm sng phun khi kt thc ng sn. K thut sn km s dn n hao ph nhiu sn. Tt c cc vt chy, vng u phi chi u hoc mi mn khi sn ng rn.

9.4.3. Cc vng d b hng c x l bng cch qut to di sc. Phng php qut hoc bi trt c s dng cho cc vng khng th a sng phun hay chi qut vo nh vt nt, ng nt

9.4.4. Cn theo di i vi loi v t l dung mi, nhit v k thut sn trnh cho sn khng qu nht, qu kh hay qu long khi ph ln b mt thp.

9.5. Thi cng bng phng php ln

Con ln phi sch s v m bo l vt liu khng tan trong sn mi c php s dng. Con ln c nhiu loi vi di, ng knh, loi si v di si khc nhau. Chiu di s dng trn b mt kim loi thng t 6 19 mm. Si di hn c th sn c nhiu hn nhng khng to c b mt mn. V vy chng s dng cho cc ng dng b mt khng cn mn hay sn kh nhanh. Cc con ln c lng ngn cho b mt mn hn, do thng p dng cho lp sn ph ngoi. Ngoi ra cn c loi con ln dng cho ng v hng ro, v con ln p lc sn lin tc.

9.5.1. Con ln phi c nhng xung sn cho ti khi thm hon ton v sau ln dc theo ng cn sn cho ti th lp sn thm t ln b mt. Ln u tin ca con ln nn sn ra ngoi y ton b bt kh c trong con ln ra ngoi. K thut ln ng cn p dng con ln c dng V hay W ty theo kch thc ca khu vc cn sn. Cc lp ph sau c ln qua lp y cc hnh vung to ra ban u. Ch nn ln vi p lc va phi, p lc ln c th gy ra bt khi trn mng

cng nh lm bt kh thm vo con ln. Qu trnh sn cn hon thnh vi mt nt nh vung gc (thng l chiu thng ng) to ra b mt mn v bng phng nht.

9.6. Phng php khc

Cc phng php th cng khc sn nh dng c sn dng tm, gng tay, chi cao su hoc bay c s dng khi sn cc cu kin c bit, hoc trong cc trng hp m cc phng php sn thng thng khng thch hp do v tr hoc hnh dng ca kt cu.

9.6.1. Tm sn lm t mt loi vi tng hp dng cun gn vi mt ming xp. Kch thc tm sn sn thng thng l 100 nm x 175 mm vi chiu di si 5 mm. Thng s dng tm sn trong trng hp b mt ln tng t nh dng con ln.

9.6.2. Gng tay s dng sn l dng bao tay da cu, c nhng vo sn v trt ln b mt. Phng php ny thch hp i vi cc b mt hnh ng v lan can.

9.6.3. B sn bng bay thng c dng cho cc lp mng ph dy.

9.7. T l sn thi cng

Ch dn k thut quy nh v chiu dy ti thiu v ti a cho mi lp sn. Yu cu c tng cng trong thnh phn sn cn tnh ton mng sn t sau khi kh c dy t tiu chun quy nh trong 6.3.3.2 v o dy mng. Vic o dy mng t l cn thit m bo chnh xc lng sn thi cng. Khi mng sn kh, ngi gim st cn phi kim tra ti ch vi thit b o mng sn kh nghim thu. Vic o dy mng sn s cung cp nhiu thng tin hn l nhn trc quan, phng php ny c th khng xc nh c ng u ca mng sn. Thit b o dy v phng php o c quy nh trong phn 10.2.5 v 10.2.6. o v kim tra dy bng phng php khng ph hy l phng php dng cho b mt kim loi.

9.7.1. Yu cu v chiu dy v ph p dng cho ton b kt cu, khng phi cho mt phn ring bit. iu quan trng l ngi gim st phi kim tra tt c cc v tr v kim sot dy i vi mi lp sn. V d, nu yu cu ti thiu mng kh phi dy 50 m , ngi kim nh phi m bo rng dung sai ca mng phi nm trong khong cho php trong SSPC-PA2, ASTM D 7091. Cc vng kim tra phi xc nh v c ghi li c th kim tra dy ca mng mi. Vi thit b kim tra khng ph hy th v tr o di 15 m v cao 1,8 m c th kim tra trong 30 pht, cc khu vc b mng c nh du v ghi li trong s kim nh. V ngi gim st trn cng trng c th khng phi l ngi gim st v lnh vc sn, do kt qu cn ghi li cn thn v gi bn sao cho ngi gim st trong ngnh c quyt nh ph hp vi lp sn tip theo.

10. Yu cu b sung

10.1. Thng gi

Vic trang b h thng thng gi l cn thit khi sn trong mt khng gian kn, nhm trnh bi v nh hng ca dung mi.

10.2. Sn sa li

Thng p dng sau khi hon thnh cc cng tc nh sau khi tn inh, hn, bt vt, bulong, khi cc v tr c sn ph s b nh hng. Ch h hng v cc khu vc cn trng cha sn cn c x l, lm sch, v sn li cn thn vi mt lp sn mi hoc lp lt mi. Thm vo , cc ng nt v vt nt nh cn c lm sch v lp y bng mt lp cht trt cho php theo yu cu k thut. Cc lp sn ring bit sau mi c qut ln kt cu.

10.3. Lch trnh sn

Nh quy nh ti 5.4.4, qu trnh sn c chia lm cc vng, cc b phn .. mi lp sn hon thnh phi c ngi gim st chp nhn mi c sn lp tip theo.

10.4. Mng sn hon chnh

Mi mng sn sau khi hon thin phi c dy ng nht, khng b khuyt v c l. V tr no qu mng hoc cha c sn s phi sn li v phi m bo kh trc khi sn lp tip theo.

10.5. Thi gian sn lp tip theo

Mi lp sn phi m bo kh hon ton v t chiu dy trc khi sn lp k tip. Mt lp sn c coi l kh sn lp k tip khi khng c cc hin tng nhn, phng rp hay mt bm dnh. Vi hu ht cc sn, thi gian kh cho mi lp ph k c trong iu kin ti u, ph thuc vo

thnh phn ca n v ca cc lp tip theo. Do , sn gc du c th mt 2 - 3 ngy kh sn lp tip theo cng loi. Tuy nhin, c th cn 3 4 thng ng rn hon ton mng sn i vi sn vinyl hoc loi khc c cha dung mi mnh trong thnh phn sn. Mt s loi sn c quy nh thi gian ti a sn lp k tip. Nh sn xut s a ra thi gian sn lp tip theo.

10.6. Sn khng t yu cu

Kh nng hng ca h sn hon thin c th gy bi mt s yu t. Hu ht l do khng tun th cc yu cu k thut ca qu trnh kim tra, gim st trong cng vic x l b mt, trong gim st cht lng sn, thi cng sn, cng nh gim st cc iu kin trong qu trnh thi cng sn v kh nng ng rn, thi gian kh ca mng sn. Mt khc, sn hng c th do ch tiu k thut khng tng thch vi mc ch s dng. Sn hng cn phi c loi b hon ton, lm sch li b mt v thay th bng loi sn c ch nh.

11. Thit b kim tra

11.1. Quan st bng mt thng

Vic quan st bng mt thng l quan trng nht trong vic kim tra, gim st thi cng sn. Tuy nhin, cc dng c o c kh cng gip cho ngi gim st th hin cho ngi thi cng sn thy rng cng vic ca h c th c kim tra trong sut qu trnh thi cng v sau khi hon thnh.

11.1.1. Thit b o nhm b mt T vn gim st, gim st c th kim sot nhm b mt thp c nh g. S dng phng php kim tra quy nh ti ASTM D 4417 khng nh cc b mt tha mn cc yu cu quy nh. Mt s thit b ch yu:

11.1.1.1. Dng c so snh nhm b mt so snh trc quan nhm vi 1 a chun xc nh nhm b mt thp c lm sch bng ct, ht mi v vn thp.

11.1.1.2. Dng c o chiu su rnh vi cc im hnh cn xc nh chiu su cc rnh ca mt ct.

11.1.2. Kh nng bm dnh ca lp ph

T vn gim st, gim st nn mang theo 1 con dao nh xc nh kh nng bm dnh ca mng sn ln b mt vt liu ti nhng ch xut hin phng rp. y l mt th nghim ch quan v ph thuc vo kinh nghim ca gim st vin. Phng php kim tra bng dao ct to mng li m t trong ASTM D 3359, ASTM D 6677, TCVN 2097: 1993 c s dng nhiu hn.

11.1.3. Thit b bm dnh

c quy nh ti ASTM D 4541 nhm xc nh lc cn thit nh mu kim loi c gn vi b mt sn ph.

11.2. Thit b kim tra hin trng

Thit b kim tra trong lnh vc ny nn m bo hot ng tt T vn gim st sn sng s dng khi cn thit.

11.2.1. Thi gian kh v ng rn

Thi gian kh v thi gian ng rn u phi xem xt cn thn v u c th nh hng ti cht lng sn. Nhit ti thiu yu cu cho phn ng ng rn mng sn v cc mng sn ph h nc khi nhit qu cao s kh thi cng ng thi gy ra hin tng r mng sn. Sn v c giu km v sn ng rn m uretan yu cu iu kin m ti thiu ng rn. Nhng iu ny s c lu bi Nh sn xut.

11.2.1.1. Nhit k

Ngi kim nh phi lun c mt vi nhit k c khong nhit t - 18 oC ti 65 oC o nhit khng kh. Nhit k tng t hay nhit k o nhit sn, dung mi. Nhit k b mt phng o nhit b mt.

11.2.1.2. m tng i v im sng

m k gm c mt nhit k t v mt nhit k kh dng xc nh m v biu im sng l mt cng c rt hu ch. Dng c c th cm tay hoc dng in cng tt nh loi k thut s. Cc iu kin kh quyn, gm c m tng i, nhit b mt, im sng v nhit khng kh cn phi c theo di v ghi li thi im lm vic.

11.2.2. Tnh ng nht ca mng sn

y l mt tnh cht quan trng v bn ca mng sn lin quan n dy ca mng v dy ng u c th thc hin c mt phn nh ng nht ca sn.

10.2.2.1. Cc o nht

C cc trng hp c xut hin ch mng hn, do cn cc thit b o c ca sn thi cng ti hin trng. Trong khi ch a ra c mt phn thng tin v nht ca cht lng, cc cc Zahn l thit b c th dng xc nh c ca sn v cc cht lng khc. Thit b gm c 1 vin bi v cc thp khng g c ming di y. Gn vi cc l 1 vng cm tay c ch m trn nh nhm treo cc v tr thng ng khi a cht lng vo kim tra. Vic kim tra ny c chi tit ti ASTM D 4212 hoc TCVN 2092 : 2008.

11.2.3. Cc o khi lng ring (kg/l)

Khi ngi kim nh cn kim tra khi lng ring ca sn, nu khi lng kim tra thp hn so vi khi lng quy nh theo tiu chun k thut hay theo d liu ca Nh sn xut, iu cho thy sn khng c sn xut ng hoc loi dung mi s dng khng ph hp, trong khi nu khi lng ring ca sn trong mt thng cha c gi tr ti cc im l khc nhau, c ngha l sn cha c khuy trn n ng nht. Khi lng sn trong cc o th tch 1 galon xc nh ti 25oC hoc nhit khc theo quy nh. Cc c 1 np v l trn thn, khi a sn vo y nhit thp hn nhit quy nh mt cht, khi lm nng hn hp sn, lng cht lng thot ra ngoi s b loi b. Khi cc y em lau sch bn ngoi v cn. Mt cn ch cn c nhy 0,1g l khng nh chnh xc khi lng ring ca sn. Chnh lch gia lc y v lc rng ca cc chia cho 10 l khi lng tnh bng pound ca 1 gallon sn. Nhn vi 119,8 s c khi lng g/l. Nguyn tc s dng thit b trnh by chi tit ti ASTM D 1475.

11.2.4. Thit b o chiu dy mng sn t

y l thit b dng o dy mng sn ngay sau khi sn ln b mt vt liu. Ch rng c th c sai st trong kt qu nu dng o i vi mng sn kh nhanh nh sn v c giu km v hay sn vinyl. Nu thit b ny dng o dy mng t ca lp sn tip theo, cn phi rt cn thn do mt phn mng sn ng rn bn di c th b ln khi o, do dy ca mng b ln hn thc t . Nu s dng khi lp u tin rt mm, thng cho kt qu khng chnh xc. Do vic rt quan trng l phi ghi li v lu gi cc kt qu o.

11.2.4.1. Thit b o chiu dy mng sn theo nguyn l tng tc ha hc (interchemical)

Thit b c ln ln mng sn t trn mt mt phng. Kt qu o chiu dy mng sn c c trc tip trn thit b, vi chiu dy theo micromet. Chi tit theo hng dn ti phng php A, ASTM D 1212.

11.2.4. Dng c n c vch chia n m - o chiu dy mng sn t

L thit b dng o chiu dy mng sn va thi cng xong. Dng c c t vung gc vi b mt mng sn mi thi cng, cn t sau nhc ra m khng c chuyn ng trt. Chiu dy thc ca mng nm gia bc cao nht ca b mt c ph sn vi bc cao nht tip theo cha c ph sn. Chi tit c trong phng php o ASTM D 4414.

11.2.5. Thit b o dy mng kh

L thit b quan trng v bn ca mng sn lin quan trc tip ti dy ca mng. C 2 loi thit b thng s dng l thit b o dy khng ph hy mng v c ph hy mng. Thit b khng ph hy mng c u tin hn v khng lm hng mng sn. Thit b ph hy mng o dy thng qua vic ct hoc xm nhp ph hy bng kim hoc li ct cng vi b phn o khong cch di chuyn ca li t mt sn ti b mt vt liu nn. Loi ny gy ph hy lp sn, do cn thit phi ch ti lp lt v ngn chn hin tng g st ti im o. Mt dng thit b ct c m t trong 10.2.5.4.

11.2.5.1. Thit b o dy mng kh khng ph hy mng

c s dng rng ri trong lnh vc kim tra sn, i vi kim loi en da trn vic o t tnh, kim loi khng c t tnh th da trn dn in v dng xoy. Tt c cc loi khc nhau u i hi c hiu chun vi tiu chun, dy phi c bit v nm trong phm vi vi dy lp ph cn o. Cc hiu chnh phi thc hin vi cng kim loi, cng nhit v dy, trn 1 ng vin di lp sn. D 1186 v D 1400, D 7091 m t cc th tc o trn. Vic o trn b mt th c nhm

thay i c th dn n hiu sai kt qu, tr trng hp c hiu chun trn cc b mt ging ht nhau.

11.2.5.2. Thit b o dy bng t trng

S dng mt nam chm in c ngun cung cp lin tc hay mt nam chm vnh cu. Da trn c s lp mng khng c t tnh s lm thay i lc t hay t thng ca kim loi. Nu thay i l mt hm ca dy mng, thit b s cho bit dy ca mng sn. Vic o t tnh c th b nh hng bi khi lng ca thp, hoc hn in ti v tr o. Phng php thc nghim ASTM D 1186 m t cc thao tc s dng thit b o dng t trng. Phng php o cng c m t theo SSPC PA2 vi hng dn o trn cc khu vc khc nhau v dung sai theo dy mng sn.

11.2.5.3. Thit b o dy loi dng xoy

Da trn hin tng in cm v dng xoy. Phng php ny c m t trong ASTM D1400, ASTM D 7901.

11.2.5.4. Thit b o dy mng sn cm tay

Thit b kim tra ny c thit k o bng vic quan st hin vi mt ct thc hin trn mng sn. Li ct Cacbua Vonfram thc hin ct xuyn qua mng sn vo b mt nn thnh mt ng hp theo mt gc nht nh. dy mng trn bt k v tr no n nh u c th xc nh c, cc mng ph c bit c th c o theo cch c bit ring, v d nh theo mu sc. Cc mng sn khng qu gin hay qu mm, khi vic ct x s xy ra nhiu hn l ct xuyn qua mng, dn n sai lch kt qu o. Phng php o ny c trnh by trong ASTM D 4138.

11.2.6. Pht hin khuyt tt

Cc khuyt tt xut hin trn mng sn c th khng thy c bng mt thng. m c th xm nhp vo mng sn qua khuyt tt . Vic th nghim c thc hin trc khi lp sn ngoi ng rn c th kp thi sa cha nu c xut hin cc khuyt tt. Thit b pht hin khuyt tt c th s dng in p thp hoc cao. Phng php th nghim c m t ti ASTM D 5162.

11.2.6.1. Thit b pht hin in p thp gm c mt tm bt xp gn vi pin v bo hiu.

Mt dy dn c gn vi vt liu thnh mch in. Ming bt c thm t v di chuyn trn b mt sn, nu gp l khuyt s hnh thnh mch in kn v chung bo s ku. Mi im c pht hin cn phi nh du v lm kh trnh bo hiu li. Bo hiu in p thp c th dng cho mng c dy 508 micromet (20 mil).

11.2.6.2. B pht hin dng in p cao

C nguyn tc hot ng tng t nh b in p thp, tuy nhin khng c ming bt t, thay vo l in cc c in p cao, khi a qua vng c l khuyt hay qu mng, s c mt tia la in phng ra t in cc ti b mt o. in p cao c th thay i rng u ra. Thng s dng l 3,9 V/m . (100 V/mil) tr trng hp nh sn xut c quy nh khc. in p cao c s dng khi dy mng sn ln hn 506 m (20 mil).

PH LC A

(Tham kho)

Danh mc kim tra

Danh mc ti Bng A1 lit k nhng cng vic cn thit kim tra cht lng mng sn trong cng xng. Mt s chi tit dnh ring cho c th mt s d n. Cc c im k thut ca qu trnh sn khc nhau phi c loi sn s c s dng. Cc chi tit khc nhau s c m t trong vn bn hng dn ny.

Bng A1 - Danh mc kim tra

I iu kin b mt kim tra Phng php, thit b kim tra Ghi ch

1. Vt hn, ng hn;

2. Du, m;

1. Quan st, kim tra trc tip;

2. Quan st, lau bng gi sch;

C nhiu loi vt liu, tp cht nu khng lm sch khi b mt s nh hng n tui th ca

3. Phn ha, nm mc;

4. Ph bo v tng v tr.

3. Quan st trc tip hoc dng knh phng i;

4. Quan st trc tip

lp ph. Gm c du, m, t, vt hn, x hn. cc cht ny lm mng sn bm dnh km ln b mt kim loi. Vic quan st k l bc quan trng x l b mt ph hp cho vic sn ph.

II iu kin mi trng Phng php, thit b kim tra

1. Nhit khng kh;

2. Nhit b mt;

3. Hng, tc gi;

4. im sng, RH;

5. m quan st.

1. Nhit o khng kh;

2. Nhit o b mt;

3. Thit b o gi, hoc d bo thi tit;

4. m k treo;

5. Quan st trc tip.

iu kin mi trng phi nm trong gii hn thch hp cho s bm dnh v to mng sn.

III An ton lao ng Tham kho

1. Qun o bo h;

2. Mt n khng c;

3. Knh bo h;

4. Bo h tai;

1. Tiu chun an ton OSHA;

2. Phiu sn phm MSD;

3. iu chnh theo tng quc gia.

C mt s tiu chun an ton b tr theo qu trnh sn; cc quy tc an ton phi c theo di, cc iu kin v thc t khng an ton phi c bo co cho ngi qun l.

IV Lm sch bng phun ct Phng php, thit b kim tra

1. Loi v kch thc cht mi mn;

2. Lm sch v lm kh cht mi mn;

3. Kim tra mi mn lp;

4. Kim tra khng kh nn;

5. p sut kh nn u phun;

1. Phn loi bng sng v quan st trc tip;

2. Quan st trc tip;

3. Kim tra vi nc;

4. Bn thm trng;

5. Thit b kim tra p sut.

Lm sch nh phun ct c s dng loi b cc vt liu khc bm trn b mt ca vt liu ng thi lm tng nhm ca b mt nh cc ht ct, mt kh, c phun vo b mt kh mi mn bng khng kh nn. Cn thn trng v s dng thit b phun ct cn thao tc thch hp.

V X l b mt Phng php, thit b kim tra

1. Loi b bi v ht mi mn;

2. Mc lm sch b mt;

3. o nhm

4. Kho st bng t trng.

1. Quan st trc tip;

2. Tiu chun hnh nh v xc nh bng vn bn;

3. Bn sao v my so nhm b mt;

4. Thit b o dy bng t trng

X l b mt l qu trnh quan trng nh hng ti cht lng ca mng sn. Cc chi tit c xc nh tng mc theo thi gian s dng v loi sn s dng. nhm b mt nhm b mt ca kim loi trn c nh hng c ch n hiu sut ca mng sn nu n c th lm tng kh nng bm dnh ca mng trn vng .

VI Thi cng sn Phng php, thit b kim tra

1. Thi gian chun b b mt n khi sn;

1. Ghi li;

2. Cc o nht theo Test D

Nhiu yu t quan trng m bo cht lng thi cng sn. Cc chi tit c ghi li trong hng

2. nht sn;

3. Kim tra khng kh nn;

4. im bao ph bo v;

5. Thi im bt u sn;

6. sch khng kh xung quanh;

7. Gim st nhit v m khng kh;

8. Qu trnh pha trn sn;

9. Quan st bc u;

10. T l khuy trn thch hp;

11. dy mng- t, - kh;

12. Theo di thi gian sn li;

13. Lm sch lp sn;

14. Khuyt tt ca mng sn.

4214;

3. Bn thm trng

4. Quan st trc tip;

5. Ghi li;

6. Quan st trc tip;

7. m k;

8. Ghi li th t trn hp cc thnh phn sn;

9. Quan st trc tip;

10. Quan st trc tip

11. Thit b o dy mng;

12. Ghi li thi gian hon thnh;

13. Quan st trc tip;

14. Thit b xc nh l khuyt mng.

dn ny. c bit, cn ch : Kho st dy mng kh l quan trng nht v kh nng bo v vt liu quan h trc tip ti dy mng. C hai cch xc nh dy mng, ph hy hoc khng ph hy.

VII Ghi kt qu Phng php, thit b kim tra

1. Ghi ton b kt qu, ngi thi cng sn, Nh sn xut, hn hp, iu kin bo qun.

2. Ghi li quan st theo cc mc I, II, IV, V v VI

1. S ghi kt qu Lu li s kt qu ghi y cc hot ng gia ngi gim st v ngi thc hin hp ng ch yu trnh tranh ci trong hp ng. Tt c cc chi tit ca tng bc trong qu trnh sn cn c ghi li cn thn.

MC LC

1. Phm vi p dng

2. Ti liu vin dn

3. ngha v ng dng

4. Chun b kim tra

5. Phng php v yu cu chun b b mt

6. Bo qun v x l sn

7. Xem xt iu kin v thi tit

8. Thi cng mng sn

9. Thi cng bng phng php phun

10. Yu cu b sung

11. Thit b kim tra

PH LC A