Asbestos-containing Materials Research Articles

석면함유 건축물의 관찰조사를 통한 실내공기 중 섬유 농도 변화 요인 추정

Objectives: The objective of this study is the estimation of factors influencing airborne fiber concentrations by means of an observation survey of asbestos-containing materials in buildings. Methods: Forty-five samples were collected from four commercial buildings by NIOSH Method 7400 and classified according to current condition, potential activity, construction year, and operations and maintenance(O&M). Results: Airborne fiber concentrations by current condition(classified as good, fair and poor) were significantly different(p 0.05). Conclusions: Airborne fiber concentrations in asbestos-containing buildings had weak relationships with current condition and potential activity.

대학캠퍼스 내 석면함유자재의 사용실태 분석을 통한 효율적 처리방안에 관한 연구 - 대구 소재 K 대학을 중심으로 -

If inhaled in human body, asbestos fibers could cause serious diseases. Still asbestos-containing materials(ACM) have been much used in structures including school buildings. However, as of now, there has been no asbestos management plan for university buildings. This study, against this backdrop, seeks to analyze the status quo of asbestos application in university buildings and present effective method to dispose of ACM. To this end, the solid samples of suspicious ACM were collected from 103 building structures in the university K in Daegu Metropolitan City, South Korea for analysis herein. As a result, of the total 1,548 specimens, 401 were found to have asbestos. The ACM have four different types - tex, bamlite, gasket and slate. Of the total <TEX>$127,846.67m^2$</TEX> ACM, tex was found to account for <TEX>$125,730.41m^2$</TEX> (98.3%), the largest part. According to the purpose of use, lecture buildings were found to have 50.7% share of tex areas among the total floor area of buildings, topping the list. When considering all of the factors including building usage purpose, construction year, building use ratio, asbestos area ratio, etc. it was found herein that lecture buildings, research buildings and dormitories were the first to remove ACM.

Exposure to airborne asbestos in thermal power plants in Mongolia.

Coal-fired thermal power plants (TPPs) in Mongolia use various types of asbestos-containing materials (ACMs) in thermal insulation of piping systems, furnaces, and other products. To investigate the occupational exposure of insulation workers to airborne asbestos in Mongolian power plants. Forty-seven air samples were collected from four power plants in Mongolia during the progress of insulation work. The samples were analyzed by phase contrast microscopy (PCM) and transmission electron microscopy (TEM). The average phase contrast microscopy equivalent (PCME) asbestos fiber concentration was 0·93 f/cm(3). Sixteen of the 41 personal and one of the area samples exceeded the United States Occupational Safety and Health Administration (US OSHA) short-term exposure limit of 1·0 f/cm(3). If it is assumed that the short-term samples collected are representative of full-shift exposure, then the exposures are approximately 10 times higher than the US OSHA 8-hour permissible exposure limit of 0·1 f/cm(3). Power plant insulation workers are exposed to airborne asbestos at concentrations that exceed the US OSHA Permissible Exposure Limit. Action to mitigate the risks should be taken in Mongolia.

A Study on the Asbestos Risk Assessment with Usage of Building

Asbestos collectively refers to a set of naturally existing silicate minerals with fibrous structures, and is a natural mineral in fibrous forms that was originally serpentines or amphiboles. Because of its properties such as resistance to heat, chemical resistance and corrosion; tensile strength; sound absorption; and affordable prices, it had been widely used as building materials, fire resistant and retardant, thermal and heat insulation, sound absorbent, and electrical insulation. Since the prolonged inhalation of asbestos can cause serious illnesses such as lung cancer, mesothelioma, and asbestosis after an incubation period of 20 to 40 years, the mineral was classified as Group 1 carcinogen by the International Agency for Research on Cancer. In Korea, asbestos-containing construction materials had been widely used until asbestos was added to the hazardous substance requiring permission for use by the Occupational Safety and Health Act, and use of asbestos was totally banned in February 2009. This survey was conducted with 45 buildings to assess asbestos-containing materials used by usage of building. It was found that asbestos-containing construction materials were used in 27 buildings out of 45 buildings surveyed.

Development and Application of a Framework to Examine the Occurrence of Hazardous Components in Discarded Construction and Demolition Debris: Case Study of Asbestos-Containing Material and Lead-Based Paint

AbstractRegulations that dictate the management of asbestos-containing materials (ACM) and lead-based paint (LBP) debris in the United States require these materials to be managed in a specific manner at the job site to reduce potentially hazardous exposure to site workers, and the disposal of the materials is regulated through notification and special handling requirements. However, management of ACM and LBP from residential projects are afforded some exemptions in U.S. regulations; thus, some quantity of these materials may be delivered to a disposal facility, thus representing a potential exposure concern for landfill workers because ACM and LBP cannot be detected through visual inspection. A novel characterization framework was developed to quantify the occurrence of ACM and LBP in discarded construction and demolition (C&D) debris. A total of 266 loads of debris and 307 samples of potential ACM were collected from 10 landfills in Georgia with a total of four detections of asbestos (frequency of 1.3%)...

Climate Change Highlights a Potentially Dangerous Trade-off.

Climate Change Highlights a Potentially Dangerous Trade-off.

The concept of ‘end of waste’ and recycling of hazardous materials: in depth characterization of the product of thermal transformation of cement-asbestos

AbstractSelected samples of asbestos-containing material (ACM) with different Ca/Si ratios have been treated thermally at 1200°C for 15 min to obtain an ‘end of waste geo-inspired material’. Before and after treatment, micro-Raman spectroscopy allowed the investigation of both powdered and massive samples by directing the laser beam onto crystals with elongated morphology, thin fibres and the matrix. In the raw samples, chrysotile and/or crocidolite were detected. After the thermal treatment, no asbestos phases were identified in the Raman spectra collected on fibrous or fibre-like morphologies. The scanning electron microscopy/energy dispersive spectroscopy investigations confirmed the onset of a pseudomorphic process during annealing, leading to the complete transformation of asbestos minerals into non-hazardous magnesium or calcium magnesium silicates such as forsterite, monticellite, a˚kermanite and merwinite.The identification of such mineral assemblages was inspired by the close inspection of a natural counterpart, the high-temperature contact metamorphic imprint due to the intrusion of a sill into carbonate rocks. The process turned out to occur largely at the solid state and involved substantial mobilization of Ca and Mg to form a spinel phase (namely MgFe2O4) which was recognized in the matrix and within, or close to elongated morphologies.

Study on the concentration of airbone respirable asbestos fibres in rural areas of the Lublin region in south-east Poland.

The objective of the study was measurement of the concentrations of airborne asbestos fibres in the rural environment of the Lublin Region in south-east Poland. Measurements of concentrations of respirable asbestos fibres were carried out in the rural areas of the Lublin Region (Lublin and Włodawa counties) for a period of 24 months. The studies were conducted on 3 farms with various technical conditions of asbestos-containing materials: Farm A - good technical condition of asbestos products, Farm B - poor technical condition, and Farm C - with no asbestos containing products and no such products in its direct vicinity (up to 500 m). On the selected farms, 3 samples on each were simultaneously collected at 3 measuring sites. During the period 2009-2011, a total number of 216 samples were collected on all farms. Sampling was performed using JSH 16,000 stationary aspirators, with air flow velocity of 16 l/min. and sampling time 60-80 minutes. The number of fibres on filters was determined using an optical phase contrast microscope. The study showed that the mean concentration of respirable asbestos fibres on the farms examined was 296 fibres•m (-3). The highest concentrations were noted on Farm B was 529 fibres•m (-3), on average; on farm A the mean concentration of respirable fibres was 328 fibres•m (-3), whereas the lowest mean concentration of airborne respirable asbestos fibres was noted on farm C, where there were no asbestos products (30 fibres•m(-3)).

Application of microwave radiation in innovative process of neutralising asbestos-containing wastes

Presented are results of a research on a possibility to use innovative microwave heating for thermal neutralisation of asbestos-containing wastes. In comparison to traditional heating, the innovative process is characterised by up to a hundred times reduced energy consumption and two hundred times shorter processing time. Parameters of effective disposal, i.e. microwave radiation power and heating time, as well as kind and quantity of the wetting agent necessary in the microwave heating process that intensifies the process and ensures uniform heat distribution in the heated charges, were determined for five most commonly used products containing various fractions of asbestos fibres. It was demonstrated that the presented innovative and eco-minded technology of disposing asbestos-containing materials is a quick, cheap, economical and effective solution guaranteeing complete degradation of the hazardous fibres.

Quantification of short and long asbestos fibers to assess asbestos exposure: a review of fiber size toxicity.

The fibrogenicity and carcinogenicity of asbestos fibers are dependent on several fiber parameters including fiber dimensions. Based on the WHO (World Health Organization) definition, the current regulations focalise on long asbestos fibers (LAF) (Length: L ≥ 5 μm, Diameter: D < 3 μm and L/D ratio > 3). However air samples contain short asbestos fibers (SAF) (L < 5 μm). In a recent study we found that several air samples collected in buildings with asbestos containing materials (ACM) were composed only of SAF, sometimes in a concentration of ≥10 fibers.L−1. This exhaustive review focuses on available information from peer-review publications on the size-dependent pathogenetic effects of asbestos fibers reported in experimental in vivo and in vitro studies. In the literature, the findings that SAF are less pathogenic than LAF are based on experiments where a cut-off of 5 μm was generally made to differentiate short from long asbestos fibers. Nevertheless, the value of 5 μm as the limit for length is not based on scientific evidence, but is a limit for comparative analyses. From this review, it is clear that the pathogenicity of SAF cannot be completely ruled out, especially in high exposure situations. Therefore, the presence of SAF in air samples appears as an indicator of the degradation of ACM and inclusion of their systematic search should be considered in the regulation. Measurement of these fibers in air samples will then make it possible to identify pollution and anticipate health risk.

시야평가법과 포인트계수법에 의한 석면정량평가 연구

세계적으로 석면분석방법에 관한 다양한 연구사례가 발표되고 있는 가운데, 분석방법의 차이에 따른 석면함유물질(ACM, Asbestos Containing Material) 결과에 대한 관심이 대두되고 있다. 본 연구에서는 균질성이 확보된 ACM 시료를 시야평가법(visual estimation method)과 포인트계수법(point counting method)의 분석결과에 대한 비교 평가를 통하여 분석기관 및 분석자의 신뢰성 향상과 더불어 편광현미경 분석의 기초자료를 확보고자 하였다. 석면분석은 정성분석과 정량분석으로 구분하였으며, 석면정량을 위한 방법은 EPA 600-R-93-116의 시야평가법과 포인트계수법으로 총 400지점을 계수하는 방법으로 실시하였다. 먼저 준비된 시료의 균질성을 분산분석을 이용하여 확인한 결과 이상이 없음을 확인하였다. 정성분석의 결과는 백석면과 갈석면으로 확인되었고 정량분석결과는 포인트계수법이 시야평가법과 비교하여 전체적인 석면함유량이 저평가되는 경향과 함께 포인트계수법은 분석과정이 조금 복잡하고 분석시간이 많이 소요되었다. While variety of cases of studies about asbestos analysis methods are released internationally, the results of Asbestos Containing Materials (ACM) according to differences in the method of the analysis is becoming an issue. In this study, homogeneity ensured ACM samples were analyzed by visual estimation method and point counting method, and the result cound be used not only to improve the reliability on asbestos analysis of the institutions and analysts but also to obtain the basic data of Polarizing Light Microscope (PLM) analysis by comparing and evaluating. Asbestos analysis were divided into qualitative and quantitative analysis method. The quantitative analysis was performed by visual estimation method and point counting method (total 400 points) of EPA 600-R-93-116 method by using PLM. Firstly, The following was the result of homogeneity of the samples by ANOVA (Analysis of variance) and the results were satisfied. The results of qualitative analysis showed that the samples were chrysotile and amosite, and about the results of quantitative analysis, asbestos concentration determined by point counting method tend to be lower than concentrations determined by visual estimation method and also, pont counting method was a little more complicated and time-consuming.

Microwave-driven asbestos treatment and its scale-up for use after natural disasters.

Asbestos-containing debris generated by the tsunami after the Great East Japan Earthquake of March 11, 2011, was processed by microwave heating. The analysis of the treated samples employing thermo gravimetry, differential thermal analysis, X-ray diffractometry, scanning electron microscopy, and phase-contrast microscopy revealed the rapid detoxification of the waste by conversion of the asbestos fibers to a nonfibrous glassy material. The detoxification by the microwave method occurred at a significantly lower processing temperature than the thermal methods actually established for the treatment of asbestos-containing waste. The lower treatment temperature is considered to be a consequence of the microwave penetration depth into the waste material and the increased intensity of the microwave electric field in the gaps between the asbestos fibers resulting in a rapid heating of the fibers inside the debris. A continuous treatment plant having a capacity of 2000 kg day(-1) of asbestos-containing waste was built in the area affected by the earthquake disaster. This treatment plant consists of a rotary kiln to burn the combustible waste (wood) and a microwave rotary kiln to treat asbestos-containing inorganic materials. The hot flue gas produced by the combustion of wood is introduced into the connected microwave rotary kiln to increase the energy efficiency of the combined process. Successful operation of this combined device with regard to asbestos decomposition is demonstrated.

The potential use of cement–asbestos waste in the ceramic masses destined for sintered wall clay brick manufacture

Asbestos fibers are considered to be carcinogenic and to cause cancer, thus elimination of asbestos-containing materials from the environment is necessary. Currently, asbestos materials are stored in special landfills designed for hazardous wastes. However, this procedure is not a final solution to the problem and an alternative might be thermal recycling. This paper reports the results of a study on using asbestos-cement slates as an additive to ceramic masses that are typical in the manufacture of sintered clinker wall bricks. Green compacts containing various amounts (0–10wt%) of asbestos–cement wastes were sintered at temperatures of 1100–1200°C. Subsequently, ceramic product properties such as water absorption, open porosity, apparent density, compressive strength and freeze resistance were determined. The preliminary results of the study indicate that asbestos-containing materials can be used as one of the raw materials in the manufacture of clinker ceramic material, and that the origin of the asbestos–cement used does not have a significant influence on the basic properties of sintered clinker wall bricks. Main ceramic properties, such as water absorption, compressive strength and freeze resistance, comply with national standards and requirements for construction and road clinker ceramic.

Difference in Density of Fiber Bundles Exposed on Surface of Asbestos-Containing Materials--with the Aim to Reduce Time Necessary for Visual Observation

It is possible that asbestos‐containing materials (ACMs) are contained in construction and demolition waste (CDW) that is transported to an intermediate treatment facility. Therefore, a rapid method of detecting asbestos fibers at an intermediate treatment facility for CDW is required. Although a visual observation method has been developed for rapid determination, the time required to determine should be shortened further. If asbestos fibers on a certain part of the surface of CDW particles could be detected visually and observation of the other areas could be omitted, the time necessary for the observation can be shortened. In this study, the determination error rates for a certain part of the surface and the entire surface were estimated. A CDW particle whose surface remained intact when the construction material was produced, was classified as an intact‐surface CDW particle. A CDW particle that chipped off when the construction material was demolished or shredded, was classified as a broken‐surface CDW particle. Observation of only the broken surface yielded similar results to observation of the entire surfaces of non‐ACMs and ACMs. For non‐ACMs, the determination error rate for observation of one‐half of the broken surface was 1.6%, whereas that for observation of the entire broken surface was 2.2%. For ACMs, the determination error rate for observation of one‐half of the broken surface was 0.16%, whereas that for observation of the entire broken surface was 0%. From the obtained error rates, it was found that the time necessary for observation can be shortened.

The implications of ‘notifiable non-licensed work with asbestos’: Practical difficulties for surveyors

This paper describes the practical difficulties that asbestos-containing materials can present for surveyors when considering the refurbishment, alteration and, ultimately, the valuation of a building. Health and Safety Executive guidance in respect of the different types of asbestos survey is discussed as well as the competency standards that must be attained by those responsible for undertaking these types of survey. The paper also explains the significance of recent legislation introduced to comply with the European Commission Asbestos Worker Protection Directive; in particular, the additional classification ‘notifiable non-licensed work’. The Control of Asbestos Regulations 2012 identifies three distinct categories of work with asbestos — licensed work, non-licensed work and notifiable non-licensed work. Each classification is defined, and an explanation provided as to the factors that must be considered in order to determine the applicable category of asbestos work. The author provides examples of work activities within each category and a Health and Safety Executive decision flow chart is presented as an aid to the decision-making process. Finally, the paper reviews a memorandum from the Asbestos Liaison Group relating to the partial relaxation of precautionary measures when soffits made of asbestos insulating board are removed.

Determination and Sorting of Asbestos-Containing Material by Visual Observation

A rapid method for the determination of asbestos fiber at an intermediate treatment facility for construction and demolition waste (CDW) is required. Although the rapid method which involves visual observation has been developed, the determination accuracy and time are unknown. The purpose of this study was to determine the identification rate of asbestos-containing material (ACM: > 0.1w%), the time required for asbestos fiber determination by visual observation, and the asbestos content in CDW. After participating in a short training course for ACM determination, persons who did not have any knowledge of asbestos fiber determination were able to determine ACM in CDW by visual observation. Using the results of visual observation, an ACM sorting model was formulated. The model enabled simulation of asbestos content after sorting by inputting asbestos content distribution into CDW before sorting. However, 0.35 w% of asbestos still remained in the non-ACM fraction, i.e., the content was > 0.1 w%. The relationship between the number of sorters and the total sorting time for disaster waste from the Great East Japan Earthquake was presented. It was found that a very long time and a large number of people were required for sorting.

Morphological changes during enhanced carbonation of asbestos containing material and its comparison to magnesium silicate minerals

The disintegration of asbestos containing materials (ACM) over time can result in the mobilization of toxic chrysotile ((Mg, Fe)3Si2O5(OH)4)) fibers. Therefore, carbonation of these materials can be used to alter the fibrous morphology of asbestos and help mitigate anthropogenic CO2 emissions, depending on the amount of available alkaline metal in the materials. A series of high pressure carbonation experiments were performed in a batch reactor at PCO2 of 139atm using solvents containing different ligands (i.e., oxalate and acetate). The results of ACM carbonation were compared to those of magnesium silicate minerals which have been proposed to permanently store CO2 via mineral carbonation. The study revealed that oxalate even at a low concentration of 0.1M was effective in enhancing the extent of ACM carbonation and higher reaction temperatures also resulted in increased ACM carbonation. Formation of phases such as dolomite ((Ca, Mg)(CO3)2), whewellite (CaC2O4·H2O) and glushinskite (MgC2O4·2H2O) and a reduction in the chrysotile content was noted. Significant changes in the particle size and surface morphologies of ACM and magnesium silicate minerals toward non-fibrous structures were observed after their carbonation.

Recycling the product of thermal transformation of cement-asbestos for the preparation of calcium sulfoaluminate clinker

According to recent resolutions of the European Parliament (2012/2065(INI)), the need for environmentally friendly alternative solutions to landfill disposal of hazardous wastes, such as asbestos-containing materials, prompts their recycling as secondary raw materials (end of waste concept). In this respect, for the first time, we report the recycling of the high temperature product of cement-asbestos, in the formulation of calcium sulfoaluminate cement clinkers (novel cementitious binders designed to reduce CO2 emissions), as a continuation of a previous work on their systematic characterization. Up to 29wt% of the secondary raw material was successfully introduced into the raw mix. Different clinker samples were obtained at 1250°C and 1300°C, reproducing the phase composition of industrial analogues. As an alternative source of Ca and Si, this secondary raw material allows for a reduction of the CO2 emissions in cement production, mitigating the ecological impact of cement manufacturing, and reducing the need for natural resources.

The Beat

The Beat

Thermal decomposition of asbestos-containing materials

Asbestos is the common name applied to a group of natural, fibrous silicate minerals, which were once one of the most popular raw materials to be used in building materials. Asbestos was mainly used for the production of assortment asbestos–cement products. Today it is generally known that asbestos belongs to the group of hazardous materials and shows carcinogenic activity. In Poland, asbestos-containing materials are stored in special landfills. This is not the final solution to the asbestos problem because the fibrous structure of asbestos is still maintained. Therefore, methods based on recycling must be found which will be able to destroy asbestos’ dangerous fibrous structure. One of these methods may be thermal decomposition, where chemically combined water is released from the asbestos materials during heating. This leads to changes in the crystal structure and to the formation of new mineral phases. The aim of the preliminary research presented in this study was to determine the thermal behaviour as well as the structural and phase transformations of asbestos–cement materials during heating to high temperature. In the present study, three different types of asbestos-containing materials from Poland were examined. Differential thermal analysis, thermogravimetry with evolved gas analysis, X-ray diffraction, infrared spectroscopy and scanning electron microscopy were used to study the thermal decomposition of asbestos–cement samples. It was found that there were no significant differences between the type of asbestos–cement samples used—their thermal decomposition takes place in a similar way.