TCVN T I U C H U N Q U C G I A

TCVN 8790: 2011 Xut bn ln 1

TIU CHUN KIM SOT CHT LNG QU TRNH THI CNG SN PH BO V KT CU THP

Standard Guide for Painting Inspectors (Metal Substrates)

H NI 2011

TCVN 8790: 2011

2

Mc lc

Trang

1 Phm vi p dng.....................................................................................................................5

2 Ti liu vin dn......................................................................................................................5

3 ngha v ng dng............................................................................................................................7

4 Chun b kim tra ...................................................................7

5 Chun b b mt..........................................................................8

6 Bo qun v x l sn.............................................................................................................14

7 Xem xt v iu kin thi tit.....................................................................................17

8 Thi cng mng sn......................................................................................................................18

9 Yu cu b sung.................................................................21

10 Thit b kim tra................................................................................................22

Ph lc A (tham kho) Danh mc kim tra.....................................................................................26

3

Li ni u

TCVN 8790 : 2011 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

26

T I U C H U N Q U C G I A TCVN : 2011

Tiu chun kim sot cht lng qu trnh thi cng sn ph bo v kt cu thp Standard Guide for Painting Inspectors (Metal Substrates)

1 Phm vi p dng

1.1 Tiu chun ny c a ra trnh t hng dn kim tra, gim st 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, cng tc thi cng sn

lp ph, cng tc kim sot cht lng thi cng v chp thun nghim thu.

2 Ti liu vin dn

Cc ti liu vin dn sau l rt cn thit cho vic p dng cc tiu chun. 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.

2.1 Tiu chun ASTM

- ASTM D16 Standard Terminology for Paint, Related Coatings, Materials, and Applications - 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

c gia cng trn nn thp khng dn in.

- 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 xc nh chiu dy mng kh khng ph hy

trn b mt phi kim loi.

- ASTM D 1475 Test Method for Density of Liquid Coatings, Inks, and Related Products - Phng php

xc nh t trng ca lp ph 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.

TCVN : 2011

5

- ASTM D 2200 Standard Practice for Use of Pictorial Surface Preparation Standards and Guides for

Painting Steel Surfaces - Tiu chun s dng tiu chun hnh nh chun b b mt v hng dn cng

vic sn b mt 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 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 Prole of Blast Cleaned Steel - Cc

phng php xc nh b mt thp c lm sch bng phng php thi hi.

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 nhn s

kim tra 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 lt 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-Of).

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 Tin hnh kim tra gin on (Holiday) lp ph bo v khng dn in trn nn kim

loi.

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

- 29 CFR 1910.1200 Hazard Communication - Truyn t thng tin v him ha.

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 Metal 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.

TCVN 8790: 2011

6

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 trc khi sn ph li.

SSPC-PA 1 Paint Application Specications - Yu cu k thut thi cng sn.

SSPC-PA 2 Measurement of Paint Thickness with Magnetic Gages - o chiu dy mng sn bng

dng c t tnh.

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 Visual Standard for Power- and Hand-Tool Cleaned Steel - Tiu chun trc quan lm

sch b mt thp bng my v dng c cm tay.

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

cha mnh vn pht sinh trong qu trnh loi b sn.

2.4. Tiu chun TCVN

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

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

TCVN 2092:2008 Phng php o nht.

TCVN TCVN 2092 1993 Phng php o bm dnh bng dao ct.

3 ngha v ng dng

3.1 Tiu chun ny c dng hng dn nhng ni dung lin quan ti cng vic kim tra gim

st cht lng sn ph bo v. Nhiu chi tit trong c th quy nh cho trng hp c bit. Yu

cu k thut cho cc loi mng ph s bao gm cc mng ph thng c s dng. Danh sch kim

tra s dng trong lnh vc ny a ra 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 (c bng

tay cng nh bng thit b) c th kim sot cht lng thi cng sn.

4.2 Trc khi tin hnh 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 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, gii hn p dng lin quan n cng trnh. Cc chi tit ny nn c ghi li

trong s nht k trong qu trnh kim tra, gim st.

4.3 T vn gim st phi xem xt cc thng tin an ton khc c lin quan vi cng vic s c thc

hin bi nh thu.

TCVN : 2011

7

5 Chun b b mt

5.1 Chun b b mt 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 m bo cht lng vi tui th xc nh.

5.1.1 Tiu chun hnh nh (atlat) ca ASTM D2200 (SSPC Vis 1 89) c th gip cho T vn gim

st trong qu trnh gim st lm sch b mt thp, kim tra mc x l b mt bn thp cn phi t

c. Cn thit c mu thp vi kch c ln c x l b mt p ng yu cu ca d n

c th i 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

Rt nhiu vt liu, nu khng loi b khi b mt, s nh hng n tui th ca mng sn. l du,

m, vt bn, vt mi hn, v vy st... chng lm gim tnh cht bm dnh ca mng sn ln b mt

kim loi. Cc mui lng ng (clorit v sunfat) cng phi c loi b, nu khng s nh hng rt ln

ti hiu sut s dng mng sn. Cc chi tit a ra trong SSPC v c im k thut x l b mt

gm c cc phng php nh ty bng dung mi, bng dng c cm tay hay dng c c kh, v 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 dn ti lm hng mng

sn. Lp g ny kh gin v c th b gy hay b bong ra khi thay i nhit (c khi ch to v do

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 s dng. Cc ht mi th hn thng to ra 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 m bo ph kn cc

nh rnh b mt, trng hp ny khng nn s dng loi sn c nht thp do khng ph kn

c cc nh rnh k c khi c vi lp sn ph ln trn. Thng nhn thy l chiu su rnh nn

chim n 1/3 dy mng ph trong h sn. Tng kt 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 D4417.

5.3 Cc phng php lm sch

TCVN 8790: 2011

8

Qu trnh lm sch khng c xc nh ring r theo mi phng php lm sch. Cc quy nh cho

dung mi v hp cht lm sch c cung cp bi Nh sn xut phi c thng xuyn thay i

m bo bo v ngi lao ng mt cch thch hp.

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 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 hi 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 t, s hiu qu cao hn nu dng vi nc

sch, nng. Tiu chun SSPC SP 1 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 nn s dng phng php lm sch c hc. Phn phi lm sch l vng hi bo ha khi

un nng dung mi lm dung mi ngng t trn b mt kim loi. Ty nhn bng hi 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 thun tin hn lau bng dung mi, v khi dng dung mi nng th s ngng t dung mi loi b

du s khng lm bn li.

5.3.2 Lm sch bng dng c cm tay

Phng php ny dng loi b cc lp g 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 hay co bng dy kim loi, hay bn chi lng cng,

giy rp, bi thp, hay c bng ba. Vt liu bm dnh cht nu n khng b tch khi b mt c th

lm sch bng dao trt. Tiu chun SSPC, TCVN 8790:2011 hoc cc tiu chun tng t a ra chi

tit v vn ny, SSPC- SP2. Tiu chun quan st SSPC-VIS 3 c s dng theo di tnh chnh

xc ca qu trnh.

5.3.2.1 Lm sch bng dng c cm tay yu cu tt c x hn, nha ng, du m v cht bn dng

du m phi c lm sch bng dung mi trc.

5.3.2.2 Bn chi st phi cng lm sch hon ton b mt, v c hnh dng thch hp lm

sch c cc gc 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 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

TCVN : 2011

9

Phng php ny s dng lm sch cc ba via 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 xp loi bm dnh cht nu n khng th tch ra vi 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 quyt nh.

5.3.3.1 Thit b lm sch s dng nng lng (in) yu cu tt c du m, mui hn v cc cht bn

khc phi c lm sch trc vi dung mi. Lm sch bng dng c cm tay theo 5.3.2 c s

dng ph hp trc khi lm sch bng my.

5.3.3.2 Tt c cc ph kin phi thch hp vi loi hnh dng vt cn lm sch v gi sch trnh b

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, mui 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 b

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.

5.3.5 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 khng 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.

TCVN 8790: 2011

10

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 c hng dn

ti ASTM D4285.

5.3.5.3 H thng phun ct nn 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 nn thc hin cc b mt sau khi phun ct b

m. im sng thp nht l -1oC bn di nhit ca thp.

5.3.5.4 Hiu qu ca phng php phun ct theo yu cu thng thp nht bng vi yu cu k thut

x l b mt thch hp v tun theo tiu chun nh (atlat). Tiu chun ca ASTM, SSPC, 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 (TC chun b b mt theo tranh nh - tng t TCVN

8790:2011 ). Phng php B gii thch tiu chun trn nh theo SSPC. 2 b nh khng c so snh

trc tip (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 A Phng php B

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

SSPC-SP5

Sa3

Sa 3 SP5 1

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

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

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

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, hoc trong lc 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

TCVN : 2011

11

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.

5.4 Lm sch v x l cc b mt khc nhau

Trc khi thi cng bt k loi sn no b mt u phi lm sch v chun b ph hp 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 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 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 hc, cc

ng nt, cc vng tc nghn nh vng mi ni, khp ni, mt ca b mt ngang... Cc mnh vn

nm chng cht trn b mt ngang cn loi b. c bit ch ti cc im kh kim tra nh vng nh,

mt sau ca ai c hay bulong, mt di ca chi tit...

5.4.2 B mt m km

B mt c ph nn cn c lm sch v x l tun theo phng php ghi r trong hng dn

ASTM D2092. 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. Bt mu lt l ch khng bao gi c s dng trn b mt nhm. X l nhm t

nht l Loi B, phng php 3 ca ASTM D1730, a ra phng php s dng cht lm sch l axit

photphoric alcol ha.

5.4.4 Ch 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.

TCVN 8790: 2011

12

5.4.4.1 Nu lng bi (t 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. i 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 vng 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.

5.4.4.3 Cc cht bn nm trong cc hc, l trn b mt thp cng l vn cn ch . Mui chloride t

cc mui tan hay trong mi trng bin, v mui sunfat trong khng kh nhim c th lm gim tnh

cht ca h thng sn ph. Phng php phun nc p lc cao thng c dng loi b cc

cht bn ny.

5.4.4.4 Quy nh hin hnh yu cu thu gom cc mnh vn t chun b b mt a i x l. Khi cc

lp sn hin ti 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 l mt phn trong cng vic ca ngi gim st sn. SSPC

6 (CON)6 v 7(DIS)6 cung cp cc thng tin hu ch cho ngi gim st v phm vi ca hng dn

ny cn c tham kho cc tiu chun k thut. 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 ca bn thn.

5.5 Kim tra b mt trc khi sn

5.5.1 Cng trnh xy dng mi

Cn phi chc chn 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 lp ph bo v

tt trc khi tri ti lm gim nhit v hi m c th ngng t ln b mt. Khi cng vic sn v lm

sch b mt c thc hin trong nh xng, c th cho php chm vic sn ph qua m nu b

mt c lm sch bng phun ct.

5.5.1.1 B mt thp ph sn khi c chuyn ti cng trng xy dng cn phi gi 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 s m bo ca mng sn theo thi gian m bo cc

thiu st c sa cha theo quy nh trong hp ng. Khong thi gian t khi sn trong nh xng

n khi a ra cng trng phi m bo ngn m bo bm dnh ca lp ph.

5.5.1.2 Ngay 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 hi, 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 ngu nhin do hn, bt vt, ri v, cn c lm sch, sa theo quy

nh trc khi sn ph ln thp.

TCVN : 2011

13

5.5.1.3 Ngi gim st phi m bo cc 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 ph.

5.5.1.4 Ngi gim st phi xc nh cc c im k thut cng vi 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 cu trc.

Ngi gim st phi m bo cc b mt khng tip xc, nhng s thc hin vic cch ly bng cch

lp rp, phi c s lng mng ph theo quy nh trc khi b cch ly.

5.5.2 Bo dng sn li

Trong hu ht trng hp, vic bo dng sn li bao gm lm sch ti ch v c lp khu vc b

hng, sau p dng mt lp ph mi cho ton b b mt cu trc. Ngi gim st qu trnh bo

dng cn ch ti mt vi iu kin c th ny sinh trong qu trnh.

5.5.2.1 Lp ph tt khng c nh loi b s khng b ph hy khi lm sch khu vc b hng ln cn.

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 ang lm sch s c xut hin vng loang

l. 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, ngi

gim st cn chc chn du m, cc vt bn, bi v cc vt bn khc 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 k cng. 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,gim st c th kim tra di lp b mt lp

ph c hoc mi kim tra g, hoc s lng lo ca lp ph c, v nu pht hin cc iu kin ,

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 . Bt k lp ph no cho thy s

qun, rp hay nhn phi c bo co ngay lp tc ti k s thit k khu vc b loi b v sn

li. Nu cc khuyt im phm vi rng ch khng phi mt vi khu vc c lp cn thay i loi

sn khc vi loi dng.

6 Bo qun v x l sn

6.1 Bo qun sn v dung mi

Tt c cc mng ph 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 lu tr

phi t tiu chun s dng v thc hin theo vn bn hng dn ca Nh sn xut. Vt liu thng

b ph hy nhit thp nn cn gi nhit khng ng bng. Nhit qu cao s lm gim thi

gian sng ca lp ph. Nu lp ph phi gi trong 1 khong thi gian di, th hng thng cn phi lt

ngc thng cha. iu ny lm gim hin tng sa lng cng nh lm hn hp c trn u d

dng hn khi dng.

TCVN 8790: 2011

14

6.1.1 Thng cha cht to mng sn 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 lin quan ti tui th. Mng ph c

thi gian sng, thi gian gel ha, hoc cc nh hng xu khc trong sut qu trnh bo qun khi

cha s dng. 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 loi b. Nu cm thy

lp ph ny qu dy v c nh hng ti hn hp, sn cn d khng c dng cho ti khi c

kim tra v c kt lun chnh thc.

6.2 Pha trn sn

Sn nn c trn trong thng cha sch trc khi 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 thng vi cnh khuy mi cho sch, tit din phng, bt mu dng cc s c ph v c

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 khng c pha trn, cn lng ng. Sn

2 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 l loi c kh nng loi b lp v m khng tch c bt

mu. V d, li lc 297 micromet 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 hin

tng hao ht do bay hi dung mi v to thnh lp mng bc.

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 gii thch mt s qu trnh thng dng khi pha long cht to mng.

6.3.1 Mu khi u: Khi c php tin hnh pha long ti v tr lm vic v nu c s sp xp khc

(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 trong iu kin thc t v

thng nht gii hn pha long cho lp ph.

TCVN : 2011

15

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 2 mi c thm vo. Pha long c thc hin bng

cch khong 1 na sn c trn k vo thng cha sch. Dung mi ph hp yu cu c

thm vo v 2 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 thm vo khng cn phi kim nh

tr khi c lch xut hin trong s 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

sp xp c th thc hin kim tra ngay ti ch i vi qu trnh pha long v sn pha long. Tc

pha ny 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:

W = [1]

Trong :

W l dy mng t, m;

D l dy mng kh theo yu cu, m;

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

T l 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 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,

TCVN 8790: 2011

16

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 ngn 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 khc. 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.

gi nhit gim xung c th xem xt, theo v tr 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.

TCVN : 2011

17

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 , cn phi loi b

b mt sn cn x l v sn li 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 mt 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 ch 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 cng tc i khi gi thi theo hng khc mng sn phun kh khng 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, bi hay 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 xem khong

cch 1m, khng thy r ng vch xut hin khi lau 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 dng dung mi, hi nc hay cht ty ta 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 c im k thut;

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

- Mu sc ph hp theo tiu chun nhn thy 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;

TCVN 8790: 2011

18

- 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 SSPC PA 1, TCVN

8790:2011.

8.2.1 Mng sn b li

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 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 ch kh ti ch m, ph mng ln b mt v lp li trn

phn t ca nt trc . Mng sn c qut trn tt c cc im 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 m khng c php phun th c th thc hin bng cch qut 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 100mm

chiu ngang v si lng khng di qu 90mm. 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.

8.4 Phng php phun

Phng php phun c th cho 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 ln p sut thp.

8.4.1 Trang thit b phi thch hp cho mc ch s dng, phun ng cch v s dng p lc, kh 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

TCVN : 2011

19

hng dn ti ASTM D4285. Thit b phun thiu 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.

8.4.2 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 nn c gia cng thnh

lp ng nht, c s chng cho cc ra. Cc thnh phn iu chnh sao cho mng sn phun m

bo ng 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.

8.4.3 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 ...

8.4.4 c bit 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.

8.5 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 19mm. 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.

8.5.1 Con ln phi c nhng xung sn cho ti khi thm hon ton v sau ln dc theo ng

cn sn cho ti khi 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 kh 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.

8.6 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.

8.6.1 Tm sn lm t mt loi vi tng hp dng cun gn vi mt ming xp. Kch thc tm sn

sn thng thng l 100x175mm vi chiu di si 5mm.Thng s dng tm sn trong trng hp

b mt ln tng t nh dng con ln.

TCVN 8790: 2011

20

8.6.2 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

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

8.7 T l sn p dng

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, th

hin trong 6.3.3.2 v o dy mng. Vic o dy mng t l cn thit m bo chnh xc

lng sn em 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 a ra 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.

8.7.1 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 l 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. 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 15m v cao 1,8m 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 trong cng trng c th khng phi l ngi gim st v

lnh vc sn, do kt qu cn ghi li rt cn thn v gi bn sao cho ngi gim st trong ngnh

c quyt nh ph hp vi lp sn tip theo.

9 Yu cu b sung

9.1 Thng gi

Vic trang b h thng thng gi l rt cn thit khi sn trong mt khng gian kn, nhm trnh bi v

nh hng ca dung mi.

9.2 Sn sa li

Thng p dng sau khi hon thnh cc cng tc nh sau khi tn inh, hn, bt vt, bulong..., khi

cc khu vc 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 hp cht trt cho php theo yu

cu k thut. Cc lp sn ring bit sau mi c qut ln kt cu.

9.3 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.

TCVN : 2011

21

9.4 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.

9.5 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.

9.6 Sn khng t yu cu

Kh nng hng ca h sn hon thin c th l kt qu ca 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.

10 Thit b kim tra

10.1 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.

10.1.1 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 D4417 khng nh cc b mt

tha mn cc yu cu quy nh. Mt s thit b ch yu:

10.1.1.1 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.

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

10.1.2 Kh nng bm dnh ca lp ph

T vn gim st, gim st nn mang theo 1con 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 D3359 c s dng nhiu hn.

TCVN 8790: 2011

22

10.1.3 Thit b o bm dnh

c quy nh ti ASTM D4541 nhm xc nh lc cn thit nh mu kim loi c gn vi b mt

sn ph.

10.2 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.

10.2.1 Thi gian kh v ng rn

Thi gian kh v thi gian ng rn u phi xem xt k 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 urethan yu cu iu kin m ti thiu ng rn. Nhng iu ny s c lu bi

Nh sn xut.

10.2.1.1 Nhit k

Ngi kim nh phi lun c mt vi nhit k c khong nhit t -180C ti 650C o nhit

khng kh. Nhit k tng t hay nhit k ni o nhit sn, dung mi... Nhit k b mt phng

o nhit b mt.

10.2.1.2 m v im sng

m k gm c 1 nhit k t v 1 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.

10.2.2 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 ng nht

C cc trng hp c xut hin ch mng hn, do cn cc thit b o ng nht ca sn.

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 ng nht 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.

10.2.3 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 ni ln c th

TCVN : 2011

23

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 gallon xc nh ti 250C 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.

10.2.4 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 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.

10.2.4.1 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

D1212.

10.2.4.2 Kha cm tay

L thit b c ly chun o cc mng t nh n nng. Dng c c t vung gc vi b mt

sn mi, 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 D4414.

10.2.5 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

10.2.5.1 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

TCVN 8790: 2011

24

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 D1400 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.

10.2.5.2 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 D1186 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.

10.2.5.3 Thit b o dy loi dng xoy

Da trn hin tng in cm v dng xoy. Phng php ny c m t trong D 1400.

10.2.5.4 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.

10.2.6 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.

10.2.6.1 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 (20mil).

10.2.6.2 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

TCVN : 2011

25

ra t in cc ti b mt o. in p cao c th thay i rng u ra. Thng s dng l 3,9V/m.

(100V/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 (20mil).

26

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;

3. Phn ha, nm mc;

4. Ph bo v tng v tr.

1. Quan st, kim tra trc tip;

2. Quan st, lau bng gi sch;

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

4. Quan st trc tip.

C nhiu loi vt liu nu khng lm sch khi b mt s nh hng n tui th ca lp ph. Gm c du,m, t, vt hn, x hn cc cht ny gy nn s bm dnh km ca mng sn 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;

5. m quan st

1. Nhit k o khng kh;

2. Nhit k 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. o bo h;

2. Mt n phng 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 tiu 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 hot ng thch hp.

TCVN : 2011

27

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

1. Loi b bi v ht mi mn;

2. Mc lm sbmawtjch;

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 bo v 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 cu mng ph trn vng .

VI Thi cng sn Phng php, thit b kim tra

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

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

1. Ghi li;

2. Cc o nht theo Test D 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.

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