Asbestos Removal Research Articles

Towards an improved wind effect assessment for asbestos abatement: A methodology for reduced-scale experiments

During building renovation or demolition, asbestos fibers can be released which can contaminate the environment, leading to potential occupational health and public health concerns. Strict asbestos abatement procedures and regulations are in place to mitigate this risk, which involve sealing the worksite and depressurizing it relative to the outdoor environment (i.e., indoor pressure lower than the outdoor pressure) using mechanical ventilation. However, the depressurization of the containment can be breached by the effects of the wind. Hence, it is essential to identify which wind conditions are problematic and how to prevent their effects. To conduct corresponding laboratory measurements, it is first required to scale down the building and its containment zone including a working mechanical ventilation system. This paper presents an innovative methodology for conducting reduced-scale experiments on buildings equipped with mechanical ventilation systems for contaminant containment. The methodology, here explained in the context of asbestos abatement, could also be applied to any other type of particulate pollutant. The methodology of this research study includes the design of a mechanical ventilation system for depressurization; a method to scale down the building and the ventilation system for testing in a wind tunnel; and 3D steady Reynolds averaged Navier-Stokes (RANS) simulations for optimizing the positioning of the ventilation components. The methodology is applied for a single-zone building including its ventilation system, which is found to achieve the targeted indoor depressurization of −40 Pa, making it ready for wind tunnel tests.

Application of Supervised Learning Methods and Information Gain Methods in the Determination of Asbestos–Cement Roofs’ Deterioration State

This study introduces an innovative approach to evaluate the condition of asbestos–cement (AC) roofs by integrating field data with five distinct supervised learning models: decision trees, KNN, logistic regression, support vector machine, and random forest. A novel methodology for assessing the importance of 380 reflectance bands was employed, offering fresh insights into the key indicators of AC roof deterioration. The research systematically organized and prioritized reflectance bands based on their information gain, optimizing both the selection of relevant bands and the performance of the models in differentiating between low and high intervention priority (LIP and HIP) roofs. The decision tree model, when applied to the top 10 most relevant bands, achieved the highest cross-validation accuracy of 76.047%, making it the most effective tool for identifying AC roof conditions. Additionally, the random forest model demonstrated strong performance across various band groups, further validating its utility. Utilizing the open-source software Weka (version 3.8.6), this study adeptly executed relevance evaluation and model implementation, providing a practical and scalable solution for material characterization, especially in regions where resources for spectral and hyperspectral image analysis are limited. The findings of this study offer valuable tools for government and environmental authorities, particularly in developing countries, where efficient and cost-effective AC roof assessment is crucial for public health and safety. The methodology is adaptable to different urban environments and climatic conditions, supporting global efforts in asbestos management, especially in countries where asbestos regulations are newly implemented. Organized within the CRISP-DM framework, this paper details the methodological phases, presents compelling results on reflectance band relevance, evaluates machine learning models, and concludes with prospects for future research aimed at enhancing asbestos detection and removal strategies.

Pollution of the environment and building interiors during asbestos removal as a result of lack of negative pressure in the working areas

The paper presents examples of the consequences of the lack of negative pressure in the work zone during asbestos removal. The asbestos fibre concentrations generated in those work zones were relatively low. This was due to the leakage in barriers restricting the work zone. Therefore the asbestos content in the outside air, near the renovated rooms was increasing. In the cases discussed, these works resulted in short-term pollution of the building's outdoor air to a depth of up to 15 m. Such contamination can cover the entire interior of the building. This may lead to long-term retention of asbestos fibre in the facility, despite the completion of asbestos removal. For example, non-friable asbestos-cement sheets removal in those work conditions increased indoor air by contamination up to 3000 f/m3 (outside the work zone). In the case of removing friable asbestos inside the building type “LIPSK”, indoor air contamination locally was up 21,000–51,000 f/m3, and outside the work zone to 18,000–28,900 f/m3. These values are above the average concentration of asbestos fibres in the same type of buildings (< 300–400 f/m3) in regular use.

379 Ensuring effective control of exposure during asbestos removal - Great Britain

379 Ensuring effective control of exposure during asbestos removal - Great Britain

302 Ensuring effective control of exposure during asbestos removal - The Netherlands

302 Ensuring effective control of exposure during asbestos removal - The Netherlands

283 The development of the Asbestos Removal Exposure Assessment Tool (AREAT), and its use for exposure assessment in a regulatory framework

283 The development of the Asbestos Removal Exposure Assessment Tool (AREAT), and its use for exposure assessment in a regulatory framework

Defense and Protection of the Marine Coastal Areas and Human Health: A Case Study of Asbestos Cement Contamination (Italy)

Pivotal environmental geology research was carried out in the protected area of Cape Peloro (Messina, NE Sicily, Italy). The main aims were the ascertainment of the presence of Asbestos Cement Materials (ACMs), their mapping, and, consequently, an estimation of the potential risk for human health and marine coastal environments. The beaches surveyed covered 4500 m of coastline. Through high-resolution photographic surveys, over 520 fiber cement fragments were documented on the beaches as well as in beach deposits. The materials, after microscope, SEM-EDS, and FTIR analyses, were found to be composed of Portland cement with chrysotile and crocidolite fibers. Fragments of ACMs showed typical corrugated forms with centimeter-to-decimeter sizes and prevailing well-rounded, platy, and sub-elongate shapes. In a few localities, some fragments were found to be angular or friable. Furthermore, some fragments found on the beach were covered by conspicuous encrustations of marine organisms, testifying to their long staying in shallow-water marine environments. Illicit landfills and abandoned materials were identified in natural sections on the coastal plain. Most of the rounded ACMs were characterized by their surface texture, with mm-size asbestos fibers exposed on the surface due to significant weathering and abrasion. Notably, new fragments appeared after storms. Significant criticisms have been made related to the ACMs, analogously to what was reported for other Italian marine beaches. Possible intervention and reclamation activities cannot limit themselves to removing the fragments on the beach, as fragments are immersed in the coastal sediments at different depths and are also found in the marine deposits. Here, it is underlined that any asbestos removal and reclamation activities, if not designed and based on a multidisciplinary approach and knowledge of local coastal dynamics and the meteo-marine climate, will be very expensive and ineffective.

Optimizing the Mechanical Properties of Cement Composite Boards Reinforced with Cellulose Pulp and Bamboo Fibers for Building Applications in Low-Cost Housing Estates.

Africa is the third-richest continent in the world in terms of bamboo species. Despite these laudable natural resources, most African countries still use asbestos cement board as one of their major building materials. This is chiefly due to the high cost of equipment and technologies associated with non-asbestos-fiber cement board production. The current research seeks to underscore the possibility of utilizing these massive continent resources for non-asbestos-fiber cement board production by employing the existing production process in the asbestos cement industries via an innovatively developed laboratory-simulated Hatschek process. Non-asbestos-fiber cement boards incorporating kraft and bamboo fibers were successfully produced in the laboratory using this innovative method based on Hatschek technology, with natural fibre addition in the range of 2-6 wt.%. Experimental results revealed that the Flexural strength and deflection of the board improved significantly, producing optimum values of 10.41 MPa and 2.0 mm, respectively for composite board reinforced with 10 wt.% and 6 wt.% of kraft pulp and bamboo fibers, respectively. The SEM morphology of the fractured surfaces revealed the mode of composite fracture as well as good interaction at the fiber-matrix interface. Overall, the mechanical properties of the developed composite boards satisfy the minimum requirements of relevant standards based on fiber cement flat sheets and can be employed for internal building applications in low-cost housing estates in developing countries. The outcome of this research indicates that the current industrial production process based on Hatschek technology can be employed for non-asbestos-fiber cement board production using the studied natural fiber.

Measurement and removal of asbestos in residential dwellings to be demolished-urban transformation experience in Izmir, Turkey.

Asbestos has been used extensively in the construction industry for its superior insulation properties before its health hazards were discovered and its use eventually banned. It is likely that many residential buildings built before the 2000s in Turkey contain asbestos. Therefore, it is important to raise awareness of the potential danger of asbestos exposure during demolition work and to identify asbestos-containing materials and ensure their safe removal and disposal. This study is executed to determine the residential dwellings containing asbestos in Izmir, Turkey. The research included field studies to determine asbestos presence in the buildings that were damaged during the 2020 earthquake. Air measurements and bulk samples were taken from 50 buildings that would go through the demolition process. Eleven buildings were found to contain asbestos which corresponds to 22%. The detected asbestos type was 60% chrysotile (white asbestos). Results could be helpful for future demolition work, which are conducted in the same region that includes buildings with similar properties. Also, it is expected that the database created for this study could be useful in other studies in Turkey, where accurate statistical data related with asbestos measurements is essentially non-existent.

Removal of asbestos as an intrusive contaminant from concrete construction waste

AbstractThe construction industry is the world's largest and fastest‐growing industry due to the increase in population, standards of living, and the higher demand for infrastructure. This fast growth generates huge amounts of construction and demolition waste (C&amp;D waste), which amounts to more than 25% of the total generated waste, which has become a serious environmental challenge that needs to be addressed. The asbestos content in C&amp;D waste poses a health risk and is entitled to special care, however, disposal of asbestos as hazardous waste is the only option by law. The present paper suggests the selective demolition of asbestos‐containing demolished waste rubble to be disposed of in compliance with all local and state regulations and proposes non‐asbestos rubble fraction to be recycled as an alternative sustainable management option that mitigates different adverse environmental impacts of the presently used conventional C&amp;D waste management method.

Logistics-based design of collection system for asbeston-containing roof structures

Asbestos-containing roofing materials are an increasing hazard, which justifies their replacement by environmentally friendly roofing materials. Replacements can be carried out on an individual initiative basis, but a coordinated, systemic replacement will have a more significant impact. In order for such systemic asbestos removal to be successful from economics and logistics point of view, it is necessary to plan the associated logistics processes, as asbestos removal generates a significant transportation demand due to the large amount of waste generated. In the framework of this paper, the author presents an algorithm to plan the logistic process of centralized asbestos removal. A simple calculation method is presented to determine the cost of collection.

Risk Assessment in Asbestos Removal Works

Asbest ısı ve elektrik iletkenliği düşük, fiziksel ve kimyasal etkenlere direnci yüksek bir malzeme olduğu için geçmişte inşaat, kimya, petrol, lastik ve plastik, otomotiv ve enerji sektörü gibi birçok alanda kullanılmıştır. Başta asbestozis ve malign plevral mezotelyoma olmak üzere pek çok sağlık sorununa neden olduğu anlaşıldıktan sonra kullanımını yasaklayıcı yasal düzenlemeler yapılmıştır. Fakat geçmişteki yoğun kullanımı nedeniyle günümüzde halen birçok alanda karşımıza çıkmaktadır. Asbestin uygun şekilde sökülmesi ve uzaklaştırılması oldukça önem taşımaktadır. Ülkemizde, çalışanların asbest söküm, yıkım, tamir, bakım, uzaklaştırma çalışmalarında asbest tozuna maruziyetlerinin önlenmesi ve bu maruziyetten doğacak sağlık risklerinden korunması, sınır değerlerin ve diğer özel önlemlerin belirlenmesi amacıyla Asbestle Çalışmalarda Sağlık ve Güvenlik Önlemleri Hakkında Yönetmelik yürürlüğe girmiştir. Yönetmelik, asbest tozuna maruziyet riski bulunan çalışmalarda işverenin risk değerlendirmesi yapmakla yükümlü olduğunu belirtmektedir. Bu çalışmada, L-Tipi Matris yöntemi kullanılarak konutlarda, işyerlerinde, enerji santrallerinde, maden ocaklarında ve benzeri çalışma alanlarında asbest söküm işlerinde karşılaşılabilecek risklerin değerlendirmesi yapılmıştır. Değerlendirme sonucunda karantina kurulumu ve sökümü, asbest sökümü, söküm sonrası hijyen faaliyetleri, atıkların paketlenmesi ve istiflenmesi işleri yüksek riskli işler olarak belirlenmiştir. Söküm sırasında asbest liflerinin çevreye yayılmasını önlemek amacıyla naylon örtü ile tam sızdırmaz tecrit oluşturulmalı ve uygun sağlık ve güvenlik işaretleri yerleştirilmelidir. Asbest söküm işlerinde çalışanların P3 partikül filtreli tam-yüz veya yarım-yüz maske, Kategori III tip 5/6 tek kullanımlık tulum, iş eldiveni ve iş ayakkabısı gibi uygun kişisel koruyucu donanım (KKD) kullanımı sağlamalıdır. KKD kullanımı ve bakımı konularında çalışanlara eğitim verilmesi ayrıca önemlidir. Asbestli atıklar uygun kalınlıkta çift kat naylona konularak ağızları sıkıca kapatılmalı veya uygun daha büyük naylon torbalara konulmalıdır. Üzerlerine asbestli atık olduğunu bildiren işaretlemeler yapıştırılmalıdır. Atıklar çalışma alanı içinde yaşam mahalline uzak bir yerde geçici depolanmalı ve mümkün olan en kısa sürede lisanslı araçlarla lisanslı atık bertaraf tesisine sevk edilmelidir.

Bots2ReC – Analysis of Key Findings for the Application Development of Semi-Autonomous Asbestos Removal

The removal of asbestos from existing buildings is a socially important and challenging renovation process due to the handling of hazardous materials. The EU project Robots to ReConstruction (Bots2ReC) has developed a robotic system for semi-autonomous asbestos removal for apartment buildings. The removal of plaster and tiles and the associated tile adhesive is implemented as a semi-autonomous construction task by mobile manipulators and integrated into the existing construction process. The development is based on a test-driven approach in order to obtain information about the achievable performance and the acceptance of the human operators as early as possible. The identification of the control variables for the respective tools and the embedding in the on-site process flow are named as the main reasons for the test-driven approach. The analysis of selected key findings of the project shows for the developed semantic mapping via mobile robot that a minimal, application-specific data format favours an efficient overall process control via task planning up to execution. In the development of mobile bases for the application, it can be shown that a holonomic drive is preferable to a differential drive due to the partly narrow and angled parts of the building. To carry out the intended processes and to guide the automated power tools, the in-house development of serial manipulators is necessary, since the combination of the required working space with the occurring weight and process forces cannot be solved within the requirements by an industrial manipulator. Finally, the main benefit of this papers contribution is seen in the transferable outcomes to other on-site automation projects.

Case study: The refurbishment of Lady Haig’s Poppy Factory

By 2017 Lady Haig’s Poppy Factory was in a poor state of repair and in need of significant investment to bring it up to modern standards. It provided neither a suitable working environment for the ex-service men and women who worked in the building, nor was it fully accessible for visitors. Prior to this date a full range of options had been considered for the future of the factory, including potential relocation to another site outside of the city. The Grade C listing of the building in 2019 focused attention on the opportunities for improvement rather than demolition and a scope of works was put in place to refurbish the building. This case study describes the refurbishment programme and the scale of works which were required to bring it up to standard. It includes a particular focus on asbestos removal, replacement of roof coverings and rooflights, upgrading rainwater goods, repairs to walls and accessibility improvements to allow the building to meet the needs of both employees and visitors.

Comparison of the effects of use, protection, improper renovation and removal of asbestos products on the example of typical old office buildings in Poland

The study focused on old, German building types “LIPSK” and “BERLIN” used in Poland, since the 1960s in Eastern Europe. The different operations on buildings were analysed: protection and maintenance of asbestos products, asbestos removal and inadvertent damage to asbestos as a result of building renovation. Measurements of respirable (countable) asbestos fibres in the air were carried out using the PCOM + PLM method and SEM–EDS. In the case of the accidental destruction of products, initial contamination was ≈7000 f/m3. After 16 weeks from the end of the activity and 20 days of extreme ventilation, contamination decreased to about 500 f/m3. At the same time, in similar rooms, without extreme ventilation, the pollution was above 4000 f/m3. The average increase in pollution in a dozen or so similar buildings, after asbestos removal in places beyond the work zones, ranged from ≈ 1700–2700 f/m3 and lasted for one or two years. These buildings, used without ACM destruction or after product impregnation, have maintained low asbestos contamination < 300 f/m3 for more than 10–20 years. So, due to the easy release of asbestos that occurs with any ACM removal and the increased risk of occupant exposure, these works are often inappropriate for the buildings in question.

Australia’s Ongoing Challenge of Legacy Asbestos in the Built Environment: A Review of Contemporary Asbestos Exposure Risks

Asbestos remains ubiquitous in the Australian built environment. Of the 13 million tonnes of asbestos products installed in earlier decades, an estimated 50% remain in situ today. Because of the extensive past use of asbestos, and the increasing age of these products, the potential for exposure to asbestos fibres in both indoor and outdoor environments remains high, even while the actual asbestos exposure levels are mostly very low. Sources of these exposures include disturbance of in situ asbestos-containing materials (ACMs), for example during renovations or following disaster events such as fires, cyclones and floods. Our understanding of the risk of asbestos-related disease arising from long-term low-level or background exposure, however, is poor. We provide the most up-to-date review of asbestos exposure risks currently affecting different groups of the Australian population and the settings in which this can manifest. From this, a need for low-level asbestos monitoring has emerged, and further research is required to address whether current exposure monitoring approaches are adequate. In addition, we make the case for proactive asbestos removal to reduce the risk of ongoing asbestos contamination and exposure due to deteriorating, disturbed or damaged ACMs, while improving long-term building sustainability, as well as the sustainability of limited resources.

Mongolia: Failure of Total Banning of Asbestos.

The primary uses of asbestos in Mongolia are in thermal power plants, construction and at railway companies. There is, however, limited data on both asbestos consumption and asbestos related disease (ARD) in Mongolia. The purpose of this paper is to report on the failure to completely ban asbestos in Mongolia. To write this paper, available asbestos related literature, published nationally and internationally, and legal regulations, national standards and guidelines on asbestos control were reviewed. Mongolia consumed a total of 44,421.9 metric tons of asbestos containing materials (AMCs) between 1996 and 2014. As a key indicator of ARD, 54 cases of mesothelioma were diagnosed at the National Cancer Center by pathological testing of tissue samples between 1994 and 2013. In 2010, The government made the decision to stop all types of asbestos use under the Law on Toxic and Hazardous Substances. However, there was no nationwide action plan to gradually reduce asbestos use, promote substitutes and raise awareness of health hazards and economic burdens in the future from asbestos use. There was also no planning for safe removal of asbestos currently in place. After the banning of asbestos, thermal power plants told the government that they could not produce electricity without insulation of AMCs and substitution materials were economically not feasible. Due to pressure from the energy sector and inadequate awareness of asbestos hazards, the government changed the legal status on asbestos in 2011 as a restricted chemical. Asbestos is still allowed to be used, and workers and the general community are still unnecessarily exposed to this carcinogen.

Measurements of airborne asbestos fibres during refurbishing.

Although the use of asbestos fibres in building materials has been prohibited in Norway since 1985, asbestos-containing materials (ACMs) are still found in many buildings. Lack of knowledge and awareness of these materials may lead to exposure during refurbishing. The aim of this study was to investigate the airborne fibre concentration and classify fibres found during the abatement of various ACMs. The release of fibres during short-term work tasks, such as drilling and sawing, was also investigated. Parallel air samples were collected during asbestos abetment of different building materials and analysed with scanning electron microscope (SEM) and phase-contrast microscope (PCM), respectively. Material samples were analysed with SEM. A real-time fibre monitor was used to measure asbestos during short-term work. The highest fibre concentrations were measured for samples collected during the removal of asbestos insulating boards (1.5-4.5 fibres/cm3 [f/cm3]), and the numbers were relatively similar for SEM and PCM. A large difference in asbestos concentrations was found between SEM and PCM when analysing floor materials, which were probably caused by a high number of gypsum fibres that the PCM operator counted. Thin fibres (<0.2 µm in width) were included in the SEM count and constituted up to 50% of the total fibre concentration for the asbestos cement materials. The presence of other inorganic and organic fibres on these samples probably led to similar results between SEM and PCM. Short-term work led to peak concentrations above 30 f/cm3.

136 Occupational Exposure to Asbestos

Abstract Asbestos containing materials (ACMs) are still found in many buildings even though the use of asbestos in building materials has been prohibited in Norway since 1985. Employees that may be at risk of exposure to airborne fibers are workers within the construction industry. However, firefighters and workers investigating fires may also encounter asbestos fibers in their work. The aim of this study was to investigate the airborne fiber concentration during abatement of various ACMs. A comparison of counting results from scanning electron microscope (SEM) and phase-contrast microscope (PCM) were performed for these measurements. A separate part of the study focused on thermal transformation of fibers during fires. Parallel personal air samples were collected during asbestos abatement of different building materials and analyzed with SEM and PCM, respectively. Material samples from abatement sites and from fire scenes were investigated in SEM. The highest fiber concentrations were measured during interior wall removal (1.5-4.5 fibers/cm3 (f/cm3)). Thin fibers (&amp;lt;0.2 µm in width) constituted up to 50% of the total fiber concentration for some ACMs. Asbestos fibers observed in ACMs after fire may show a thermal transformation, however, in many cases the fibers are unchanged. For ACMs investigated in this study, there seem to be a good correlation between samples analyzed by SEM and PCM if the only dominant fiber type present is asbestos fibers. Thin fibers may constitute a large fraction of the total fiber concentration released and counting these fibers are therefore important for an adequate risk and exposure assessments.

Validation and Recalibration of the Asbestos Removal Exposure Assessment Tool (AREAT).

The Asbestos Removal Exposure Assessment Tool (AREAT) was previously developed to estimate exposure to respirable asbestos fibres during abatement processes. The current study describes the validation and recalibration of the AREAT model with external data. During model validation, the AREAT model was expanded to be able to estimate asbestos exposure from an additional source category: 'unspecified asbestos remnants'. The validation dataset (n = 281) was derived from exposure measurement studies where for each exposure measurement the AREAT model parameters were coded and estimates were calculated. Pearson correlation coefficients (r) and intra class correlation coefficients (icc) were calculated as an indication of the agreement between the AREAT estimates and measured concentrations. In addition, the bias and the proportion of measurements with higher concentrations than model estimates were calculated. To expand and investigate model performance on exposure from 'unspecified asbestos remnants', a separate dataset was created with measurements collected during working with unspecified asbestos remnants, and similar validation comparisons were performed. Lastly, linear regression techniques were used to investigate possible improvements in model parameters. The model was recalibrated on a combined dataset consisting of the validation dataset and the original calibration dataset to increase model robustness. The validation comparisons showed good relative agreement (r) between AREAT estimates and measurements (r = 0.73) and a moderate absolute agreement (icc = 0.53). The overall relative bias was 108%, indicating an overall overestimation of exposure, and 4% of the estimated concentrations were higher than the actual measured concentrations. For the data subset concerning unspecified asbestos remnants, a moderate correlation between model estimates and measurement outcomes was found (r = 0.63). However, based on the low number of data in this subset, and moderate r, it was decided that cleaning of unspecified asbestos remnants is out of scope until more data are available. The results of this validation study suggested that two input parameters (product type friable material, efficacy of control measure foam) underestimated exposure. The effects of these parameters were updated to improve model performance. Compared to the original model, the recalibrated model resulted in slightly higher explained variance (62% compared to 56%) and lower uncertainty (15 compared to 17.3). The original AREAT model provided reliable asbestos exposure estimates with a sufficient level of conservatism taking into account the 90-percentile estimates. The model was further improved via the addition of a new feature and recalibration to predict asbestos exposure during the clean-up of unspecified asbestos remnants.