한국산업보건학회지, 제25권제1호 (2015) ISSN 2384-132X(Print) ISSN 2289-0564(Online) http://dx.doi.org/10.15269/jksoeh.2015.25.1.82 Original Article 석면함유천장재의안정화제희석에따른침투깊이연구 신현규 * ㆍ최용규ㆍ전보람ㆍ하주연 한국산업기술시험원 A Study of Penetration Depth into Ceiling Materials containing Asbestos according to Dilution Rate of Scattering Prevention Agent Hyungyoo Shin * Youngkue Choi Boram Jeon Jooyeon Ha Material & Components Technology Center, Korea Testing Laboratory ABSTRACT Objectives: This study is designed to analyze the penetration performance into ceiling materials containing asbestos of scattering prevention agents and investigate the change in penetration depth and viscosity according to the dilution rate of anti-scattering agents diluted with distilled water. Methods: Five different types of scattering prevention agents were spread on plate-type asbestos ceiling materials. The penetration depth of each coated ceiling material was measured by energy dispersive spectroscopy (EDS) analysis, based on X-ray fluorescence (XRF) results of the non-coated ceiling materials. Test equipment installed the ceiling materials and 60 minutes were collected at a flow rate of 10 l/min at a filter of 25 mm. Results: An EDS analysis of the cross-section of ceiling materials constructed with a scattering prevention agent revealed that potassium is detected in the process of penetrating hardener solidification and this element could be an indicator for infiltration. When anti-scattering agents with different viscosities were constructed and the penetration depth was analyzed by potassium detection assessment using EDS, the depth results with viscosities of 5.0, 2.5, and 1.9 cp were 98.5, 103, and 147 μm, respectively. Penetration performance improved with decrease in viscosity. Conclusions: For asbestos ceiling materials, it is concluded that a higher dilution rate of the scattering prevention agent leads to lower viscosity, and hence a deeper penetration depth from 156 μm to 3 mm. The asbestos anti-scattering properties according to the penetration depth will be confirmed through further study. Key words: asbestos, dilution, penetration depth, scattering prevention agent, viscosity I. 서론국내석면규정은건축물에사용된석면함유건축자재의해체 제거가주요관리방안으로제시되고있으나 (Bae et al., 2012; Jeon et al., 2013), 미국, 일본등에서는비용, 공사기간, 사후안정성등의측면을고려하여석면함유건축물의안전하고지속적인사용 을위한새로운관리방안및규정을제시하고있다. 미국재료시험협회 (American Society for Testing and Materials, ASTM) 에서는석면관리를위해둘러쌈 (Encasement) 과안정화 (Encapsulation) 방법을권장하고있으며, 뿜칠재의안정화를위한시험기준 (ASTM E 1494-92) 을제시하고있다 (ASTM, 2002). 또한, 일본국토교통성에서는 2006년건축기준법에서건축물 *Corresponding author: Hyungyoo Shin, Tel: 02-860-1574, E-mail: hgshin@ktl.re.kr Korea Testing Laboratory, 87 Digitalro 26-gil, Guro-gu, Seoul, 152-718 Received: March 3, 2015, Revised: March 23, 2015, Accepted: March 24, 2015 This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License(http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 82
석면함유천장재의안정화제희석에따른침투깊이연구 83 관리를위한석면안정화제를인증하였고, 일본의건축물에주로사용된뿜칠재의석면비산관리를할수있는규정을명시하여운영하고있다 (JTCCM, 2007; MLIT of Japan, 2009). 이에, 국내에서도석면비산안정화제 ( 이하안정화제 ) 활용에대한필요성이제시되고있으며, 2009년건설기술연구원에서는나노실리카및알카리이온을이용하여 100% 무기질계안정화제를개발하는등안정화제관련연구가진행되어왔다 (KICT, 2009). 하지만, 현재까지도안정화제자체의성분이나원리, 시공방법등에대해서명확하게검증된바가없고, 제조사별로제시되는사양에만의존하고있기때문에안정화제의기초특성및성능에대한연구가필요한상황이다. 무기계안정화제는무색, 무취액상형태의물질로, 용제가석면함유건축자재의표면또는내부로침투하여외부에서가해지는풍속이나진동등의물리적영향으로인하여발생할수있는석면비산을방지하는기능을한다. 또한, 파손면의보수작용과상부면에서적층된먼지와함께비산될수있는석면입자에대해서도안정화가가능한것으로알려져있다 (Kim et al., 2011). 최근에는안정화제가석면함유건축자재의표면뿐만아니라내부까지침투될수있어비산성능평가에파쇄시험항목이포함되어연구되고있다 (Kim et al., 2010). 파쇄성능은표면뿐아니라시료내부까지침투된안정화제가석면섬유를고착화하여비산되는석면의농도를최소화할수있기때문에표면에서내부로침투되는침투깊이가중요한특성이라할수있다. 따라서본연구의목적은증류수로희석시킨안정화제의희석비율에따른침투율에관하여연구하였다. spectroscopy(eds, X-act, OXFORD, Germany) 를이용하여미세구조와섬유상구조를가진물질의성분을분석하였다. 2. 안정화제특성평가안정화제는석면의비산방지역할을하는약품으로유기계와무기계로분류된다. 본연구에서는일본에서시판되는무기계제품 3종과국내무기계제품 2종을선정하였으며안정화제의밀도, 점도, 고형분함량, ph 등기초특성및구성성분을분석하였다. 3. 성능시험평가안정화제의비산방지성능평가는 Figure 1에서보는바와같이, 석면함유천장재를 30 30 cm 크기로절단하여안정화제로처리한후, 에어로존시험기상부에설치하여성능평가시험을수행하였으며, 자세한시험조건은 Table 1과같다. 에어로존시험장치내부에이물질이없도록청소한후천장재를설치하고 25 mm의필터에서 10 l/min의유량으로 60 분간채취하였다. 채취한공기중시료는위상차현미경 (Phase Contrast Microscope, PCM, ZEISS Axio Scope.A1, Carl ZEISS, Germany) 으로분석하였으며파손시험의경우, Figure 2에서보는바와같이 30 30 cm 크기의천장재에안정화제를도포한후직경 7 mm의드릴을이용해간격이 75 mm가되도록 9개의구명을뚫어성능평가를진행하였다. Ⅱ. 연구방법 1. 연구대상본연구에서는건축자재중석면이함유된천장재를대상으로연구를진행하였으며포함된석면의종류및함유량은편광현미경 (Polarized Light Microscope, PLM, ZEISS Axio Scope.A1, Carl ZEISS, Germany) 으로분석하였다. Scanning electron microscopy(sem, MIRA 3 XMU, TESCAN, Czech) 와 Energy dispersive Figure 1. Test equipment used to measure the concentration of airborne asbestos particles http://www.kiha.kr/
84 신현규ㆍ최용규ㆍ전보람ㆍ하주연 Table 1. Test conditions of Airozone performance evaluation Test conditions Value Angular spread(air) 90 Pressure difference 95 KPa Flow velocity 10 l/min Time 60 min Figure 3. PLM image of asbestos-containing ceiling materials Figure 2. Mimetic diagram of damaged asbestos-containing ceiling materials 4. 침투깊이평가본연구에서는천장재에처리된안정화제의침투여부와깊이를확인하기위하여성분분석이가능한 EDS 분석방법을사용하였다. 안정화제가처리되지않은천장재와안정화제가처리된천장재의 EDS 분석을통한성분비교를통해천장재표면에서수직방향으로 point 분석을실시하여안정화제성분의검출경계를확인한후, 수평방향으로이동해물질의검출여부를확인하는방식으로침투깊이를측정하였다. Ⅲ. 연구결과및고찰 1. 천장재의기초특성결과 Figure 3은석면의 PLM 사진으로, 분석결과본연구에사용한천장재는백석면 3% 가함유되어있 Figure 4. (a), (b) SEM micrographs of asbestos fibers in ceiling materials; and (c) the corresponding EDS profile analysis for the SEM image 음을확인하였다. 석면의 SEM 이미지와 EDS 분석결과를통해석면의섬유상특징과주요성분인 Mg 와 Si 성분이검출됨을확인하였다 (Figure 4). 2. 안정화제의기초특성결과안정화제 5종의고형분함량, 점도, 비중및 ph의분석결과는 Table 2와같다. 5종의안정화제가점도에서가장큰차이를보였고나머지물성으로인한차이는크지않았다. 고형분은전체적으로 10~18 Table 2. Basic properties of scattering prevention agents A B C D E Type inorganic inorganic inorganic inorganic inorganic Solid [wt%] 14~16 12~15 10~12 16~18 10~12 viscosity [cp] 5.6 2.2 2.5 5.0 1.9 specific gravity 1.11~1.15 1.08~1.12 1.10~1.15 1.15~1.18 1.08~1.12 ph 11.2 12.1 11.7 11.5 11.8 http://www.kiha.kr
석면함유천장재의안정화제희석에따른침투깊이연구 85 Table 3. Elemental composition of scattering prevention agents in wt% by XRF method Component [wt%] A B C D E Na 6.03 0.262 0.174 8.11 0.232 Mg 0.0095 0.0106 - - - Al 0.122 0.0151 0.0141 0.16 0.0849 Si 43.0 28.7 25.2 90.1 32.5 P 0.0046 - - - 0.0140 S 0.0425 0.0121-0.0703 0.033 Cl 0.153 - - - - K 50.2 71.0 72.0 1.03 67.1 Ca 0.299 0.0477 0.0341-0.186 Fe 0.202 0.0464 0.0422 0.534 - Rb 0.0166 0.0249 0.0162 - - Zr 0.0277 - - 0.0633 - Ni - 0.0244 - - - wt%, 비중은 1.10~1.25로 5가지제품모두비슷한물성을나타냈으며, ph의분포는 ph 11~12로알칼리성을띄었으며점도는 1~5 cp로분포하였다. 안정화제의 XRF 분석결과, 5종의안정화제에서공통적으로 Si, Na, K 성분이다량검출되었고, 이는무기질안정화제의기초물질로알려진 Na 및 K이 Si와다양한방식으로결합된규산염이주된성분을이루고있기때문인것으로판단되었다 (Table 3). 3. 안정화제처리후성능평가결과 30 30 cm 크기의천장재에희석하지않은안정화제를스프레이를이용하여 250 g/m 2 기준으로도포한후 Figure 1의에어로존시험기를이용하여 Table 1의조건에서성능평가를실시하였다. Figure 5의결과와같이안정화제처리를한경우에는 0.0057 f/cc로실내공기질기준 (0.01 f/cc) 을초과하지않는결과가나왔지만, 안정화제처리후 Figure 2와같이파손하고성능평가를실시한결과 0.0180 f/cc로실내공기질기준을초과하는결과를보였다. 이를통해천장재에안정화제를도포했을경우공기중으로비산되는석면의농도를감소시키지만, 천장재가파손될경우안정화제가내부로충분히침투되지않아고착화되지못한석면섬유로인해비산농도가증가됨을확인할수있었다. 따라서파손이발생되는경우를고려하여천장재내안정화제침투깊이를증가시킬필요가있다. Figure 5. PCM-asbestos fiber concentrations measured after spread-coating the scattering prevention agent and damaging the ceiling materials 4. 침투깊이평가결과 EDS 분석을통해안정화제처리전 Mg, Si, O, C, Al 등약 7가지성분이검출되었지만안정화제처리후 Mg 성분의양이크게감소하고안정화제도포전에존재하지않던 K 성분이검출됨을확인할수있었고 (Table 4), 안정화제도포후 Figure 4(c) 에서확인한석면섬유의구성성분인 Mg 검출량이감소되어안정화제가석면표면에고착된것으로판단되었다. 안정화제처리전에천장재에존재하지않던 K 성분 http://www.kiha.kr/
86 신현규ㆍ최용규ㆍ전보람ㆍ하주연 Table 4. EDS analyses results(wt%) on asbestos-containing ceiling materials before and after spread the scattering prevention agents Element A B C [wt%] Before After Before After Before After C 8.47 9.78 8.46 11.15 8.20 11.88 O 59.63 60.19 58.65 49.69 53.34 55.54 Na 0.71 2.69 0.21 5.64 0.61 1.13 Mg 13.39 9.26 15.66 0.72 11.08 0.78 Al 1.16 0.75 0.65 0.11 0.63 0.33 Si 7.04 7.31 6.90 18.51 7.25 16.02 K - 2.41-10.50-7.80 Ca 9.59 7.61 9.47 3.67 18.89 6.52 Element D E [wt%] Before After Before After C 8.2 14.36 8.25 18.54 O 58.13 55.34 56.85 53.40 Na 0.98 15.2 0.45 0.77 Mg 14.89-16.85 1.02 Al 1.29 0.23 1.25 0.51 Si 7.10 12.86 6.65 17.75 K - 2.01-3.05 Ca 9.4-9.7 4.96 Table 5. Viscosities of diluted scattering prevention agents with different concentration of distilled water of 0, 20, 40, 60, and 80% Concentration of Viscosity(cP) distilled water A B C D E 0% 5.6 3.2 2.5 5.0 1.9 20% 2.3 2.0 2.0 3.7 1.8 40% 1.8 1.7 1.7 2.4 1.3 60% 1.5 1.4 1.5 1.8 1.3 80% 1.3 1.2 1.2 1.4 1.2 이안정화제처리후검출되는것을확인하고 K성분을안정화제침투깊이확인을위한지표로선정하여 EDS 분석으로안정화제의침투깊이를확인하였다. Figure 6 및 Table 5는각각 EDS 분석을이용한안정화제종류에따른침투깊이결과와, Vibro Viscometer로측정한안정화제점도결과이다. Figure 6에서알수있듯이희석하지않은안정화제의침투깊이는평균 113 μm로 6 mm의천장재기준약 2% 정도침투되며, 내부침투가거의이루어지지않은것으로판단된다. 점도는안정화제자체가수용성이 므로증류수를이용한조절이가능하기때문에 Table 5와같이희석비율별로점도를변화시켜침투깊이를확인하였다. Figure 6에서침투깊이가가장우수했던안정화제 B를대상으로 20, 40, 60 그리고 80% 의비율로희석하여석면함유천장재에도포한후희석비율별침투깊이를측정하여모식도로나타내었다 (Figure 7). 희석하지않은안정화제는천장재내침투깊이가 156 μm인반면 80% 희석한경우침투깊이가 3.6 mm로 20배이상이었다. http://www.kiha.kr
석면함유천장재의안정화제희석에따른침투깊이연구 87 Figure 7. The penetration depth of diluted scattering prevention agent B Ⅳ. 결론 석면함유천장재의안정화제처리시천장재내부로의침투가충분히이루어지지않아외부의자극으로인한파손이발생할경우공기중으로비산되는석면의농도가급격히증가하는결과를바탕으로안정화제의침투깊이확인및향상방법을연구하였으며, 증류수를이용한안정화제의비율별희석을통해안정화제의점도를낮추어점도에따른안정화제의침투깊이를확인하였다. 성분분석결과무기질계안정화제는주로 Na, K, Si 성분으로구성되어있으며, 안정화제도포전천장재는 Mg, C, O 등이주요성분으로구성되어있음을확인하였다. 안정화제처리후석면섬유의구성물질인 Mg의양이크게감소하고안정화제의 K 성분이증가하는것을확인하였다. 따라서 K 성분을기준으로 EDS 분석을통해천장재표면에서수직방향으로 point 분석을실시하여 K가검출되지않는경계를확인한후수평방향으로이동해검출유무를확인하여안정화제의침투깊이를확인하였다. 위의방법을바탕으로증류수의비율이 20, 40, 60 그리고 80% 가되도록안정화제를희석하여점도를낮춘후희석비율별로안정화제의침투깊이를확인한결과희석시키지않은경우 156 μm침투된반면 80% 희석한경우 3 mm로희석비율이높아질수록침투깊이가향상됨을확인하였다. 따라서추후희석으로인한안정화제의침투깊이변화에따른안정화제성능평가를통해공기중비산되는석면의농도가최소화되는조건연구를진행할예정이다. 감사의글 Figure 6. The penetration depth according to type of undiluted scattering prevention agent 본연구는한국환경산업기술원생활공감환경보건기술개발사업 (2013001350002) 의연구비지원으로수행되었으며이에감사를드립니다. http://www.kiha.kr/
88 신현규ㆍ최용규ㆍ전보람ㆍ하주연 References American Society for Testing and Materials(ASTM) E 1494-92. Standard practice for encapsulants for sprayor trowel-applied friable asbestos-containing building materials.; 2002 Bae JM, Kim YC, Won AN, Hong WH. A study on the improvement of residential environment in building of asbestos cement slate through the survey focusing in seoul city-. Arch Inst Kor 2012;28(12): 399-406 Japan Testing Center for Construction Materials(JTCCM). Special review: test of capability of anti-friable encapsulant materials, building material testing information.; 2007 Jeon RY, Yu YS, Lee CS. The checklist & manual development for safe dismantling of asbestos building materials. Arch Inst Kor 2013;29(7):117-124 Korea Institute of Civil engineering and building Technology(KICT). Smart monitoring of indoor asbestos based on the distinct optical properties of asbestos from particulate matters.; 2009 Kim YH, Song TH, Lee SH. The characteristics of penetrating hardener solidification to prevent flying-asbestos material. Arch Inst Kor 2010;30(1): 241-242 Kim YH, Song TH, Lee SH. The entraining properties of plate type asbestos ceiling materials using prevent flying-asbestos coat. Arch Inst Kor 2011;31(2): 367-368 Ministry of Land, Infrastructure, Transport, and Tourism (MLIT) of Japan. Survey of sprayed asbestos coatings in privately owned building.; 2009 http://www.kiha.kr