Slate Roofs Research Articles

187P Exposure to asbestos slate roofing in households and risk of lung cancer: Case-control study

187P Exposure to asbestos slate roofing in households and risk of lung cancer: Case-control study

The Political Economy of the Roof: The New Village Movement in 1970s South Korea

This study investigates South Korea’s rural modernization project conducted under the name of the New Village Movement during the rapid industrialization period of the 1970s. The focus is on a specific event called the Roof Improvement Project within this Movement. In the 1970s, rural poverty was often portrayed through images of monochromatic village landscapes populated by dilapidated mud-walled houses crowned with coverings of faded grass thatch. Replacing the thatched roofs with something more colorful and modern was quickly identified as one of the most effective ways of showcasing ‘rural development.’ By 1978, an astonishing 2,618,000 thatched houses throughout the countryside had their old roofs replaced with a new material known as ‘slate.’ The rural ‘change’ particularly manifested through the brightly colored slate roofs lining the highways. This technicolor display propagandized development and, ultimately, legitimized the military regime’s rule. However, the new ‘modern’ roofs actually eroded farmers’ financial status and bolstered the accumulation of capital by specific industries. To trace the flow of capital extracted from farmers, this study also delves into the history of two large corporate groups - KCC and Pyŏksan - that were able to solidify the early foundation for their current business formation in the 1970s.

Asbestos Exposure Level and the Carcinogenic Risk Due to Corrugated Asbestos-Cement Slate Roofs in Korea.

Asbestos-cement slate roofs are one of the most common environmental causes of asbestos exposure. However, few studies have examined residential asbestos-cement slate-related exposure and its effects on human health. This study was performed to evaluate cumulative asbestos exposure levels and to calculate the Excess Lifetime Cancer Risk (ELCR) of residents of asbestos-cement slate-roofed houses. We reviewed previous Korean literature to estimate the concentration of airborne asbestos from asbestos-cement slate roofed buildings. Finally, eight studies were selected, and a pooled analysis was performed. The results derived from the pooled analysis were combined with the data from a health impact survey conducted from 2009 to 2016 at the Environmental Health Center for Asbestos (EHCA) of the Yangsan Pusan National University Hospital, and a carcinogenic risk assessment was performed. As a result, the representative value of the indoor exposure concentration related to asbestos-cement slate was found to be 0.0032 f/cc on average, and the representative value of the exposure related to occupational asbestos-cement slate dismantling and demolition was found to be 0.0034 f/cc. In addition, the ELCR of asbestos-cement slate related indoor exposure and occupational dismantling and demolition was found to be of medium risk, and the ELCR of residential dismantling and demolition of asbestos-cement slate was less than 10−6, indicating that the risk was low. Since there is no threshold for carcinogenicity related to asbestos, this should not be ignored even if the risk appears low, and it would be reasonable to calculate the carcinogenic risk based on total lifetime exposure. More studies on asbestos exposure scenarios and the scope of similar exposure groups through additional data collection and further analysis of risk are needed.

L’ardoise de couverture en Anjou au Moyen Âge et à l’époque moderne : l’exemple de la chapelle de la commanderie de Saulgé (Luigné, Maine-et-Loire)

La méthode d’étude mise en place pour étudier les ardoises anciennes a été appliquée aux vestiges découverts dans les reins de voûte de la chapelle à la commanderie de Saulgé. Cette approche, basée sur l’acquisition de caractéristiques dimensionnelles et morphologiques, a permis de décrire ces ardoises de couverture tant dans leur forme que dans leur mode de pose. Ces informations conduisent à restituer une couverture d’ardoises épaisses fixées au clou à joints brouillés et à pureau décroissant. À partir de ces éléments, il a été possible d’estimer la quantité de matériau mis en œuvre à plus de 13 000 ardoises pour une masse proche de 10 tonnes. Ces éléments de l’époque moderne ont été confrontés aux résultats d’autres ensembles issus de contextes angevins entre le xie siècle et le xvie siècle pour être replacés dans une perspective plus longue. Tous ces ensembles soulignent, sur toute la période concernée, la consommation préférentielle d’ardoises de couverture de second choix au sein de l’aire de production ainsi que dans un rayon d’une cinquantaine de kilomètres autour, tandis que les produits de meilleure qualité (plus fins et réguliers) restent réservés au commerce à longue distance.

Development of Nationwide Excess Lifetime Cancer Risk Evaluation Methods with Comprehensive Past Asbestos Exposure Reconstruction.

Although exposure to asbestos via various routes has been acknowledged, comprehensive exposure and risk assessment methods have not been developed at the national level. We conducted a study to reconstruct comprehensive past asbestos exposure estimations and to suggest a method to calculate the Excess Lifetime Cancer Risk (ELCR) of Koreans. The past occupational exposure reconstruction was conducted by rebuilding the previous general population job-exposure matrix (JEM). The para-occupational and household exposure estimation was based on the pooled analysis of data from other countries as well as Korea. The neighborhood exposure from occupational sources by distance was estimated by the exponential decay model. As a result, 141 JEM exposure groups across four periods including ~79, the 80s, 90s, 2000s with a ratio of 2.0:1.0:0.5:0.05 were reconstructed. The para-occupational and household exposures were 11% and 1% of the JEM respectively. The environmental exposure source concentration from outside occupational exposure was 2.5% of the inside concentration. The ratio of the concentration of environmental exposure source (C0) to distance d (Cd) was with a decay constant k of 6.834. The mean concentrations (f/cc) were 2.28 × 10−3 for outdoor, 4.65 × 10−5 for indoor, 1.95 × 10−2 for transportation activity, 4.44 × 10−2 for agricultural activity, and 4.68 × 10−2 for daily life activity in naturally occurring asbestos areas. Indoor and outdoor asbestos concentrations from living in a slate roof house were 1.73 × 10−6 and 2.70 × 10−8, respectively. For improved generalizability, validity, and applicability of the proposed method, further studies on each route with real assessments and experiments are required.

141 Haussmann égre nyíló tető

Restoration and refurbishment taking place in a historical district of Paris calls for a contemporary reworking of existing values. The mansard roof form considered to be the norm in this area usually results in a single or double floor rooftop development of dark spaces under a slate roof. To replace the material purely with glazing has two effects: firstly the traditional expectation is met, secondly a bright and vibrant interior is created. The latter being more inline with current expectations for quality of light, space and therefore wellbeing of its inhabitants. Proof that often the choice of materials, instead of bold architectural statements, can result in a quality development without need for controversy.

The nesting ecology and postembryonic development of the Columba rupestris in Tuva and Buryatia

A material on the nesting ecology of Columba rupestris was collected in southern Siberia on the territory of Tuva and Buryatia. The Columba rupestris lives sedentary in various types of localities and a small proportion in the natural rocks of open spaces. The number of this species has now decreased by 35 times compared to the 7090-es of the 20th century. It is due to the deterioration of the food supply as a result of the elimination and reduction of arable land near settlements, the reduction of livestock in private households, changes in the architecture and construction material of buildings, first of all, the replacement of slate roofs with metal profiles. The most preferred localities are medium and small rural settlements located in forest-steppe and steppe landscapes. The deterioration of habitat conditions affected the structure of nesting settlements, and colonies became small (no more than 3050 birds compared to 100200 individuals at the end of the 20th century). Breeding periods in localities are stretched from late February to mid-October, but the majority of populations breed from the 20th of March to the end of July. Birds manage to hatch their сhicks 24 times, 2,4 times on average. There are 2 eggs in a clutch, incubation lasts 17 days, and the сhicks leave the nest at 26 days of age. The paper presents features of growth and development of chicks. Nesting efficiency (ratio of the number of chicks that have reached sexual maturity to the total number of eggs laid) equals to 27%. It is noted that currently interspecific hybridization of Columba rupestris and Columba livia, which was observed relatively often in the second half of the 20th century, has almost stopped due to a decrease in the number of both species, which led to greater spatial differentiation.

Measurement of Attenuation by Building Structures in Cellular Network Bands

The power transmitted through obstacles is lower than the incident one due to reflection and absorption by them and this attenuation of electromagnetic waves reduces the radio coverage of any wireless communication system. This letter presents a study for the loss introduced by multiple building structures: brick, cavity and solid concrete block, and plasterboard walls; tile and slate roofs; and ten types of modern windows. The investigation is conducted in an anechoic chamber over the frequency range from 400 MHz to 2.7 GHz. Normal incidence is considered and both linear copolarizations (vertical–vertical and horizontal–horizontal) are tested. Strong frequency- and polarization-dependent attenuation is observed for the cavity concrete block wall and windows. The results demonstrate that the windows have the highest losses among the tested structures, which can reach up to 50 dB.

Concentration of airborne asbestos fiber in indoor and outdoor environment of a slate roofing house, and health risk assessment

Concentration of airborne asbestos fiber in indoor and outdoor environment of a slate roofing house, and health risk assessment

무인항공기를 이용한 노후 주거지역의 석면 슬레이트 지붕 조사 기법에 관한 연구

무인항공기를 이용한 노후 주거지역의 석면 슬레이트 지붕 조사 기법에 관한 연구

공장과 주택 슬레이트지붕의 석면 노출특성 비교

This study was performed to identify and quantify asbestos fibers released from two types of asbestos-cement slate roofs. One is a plant roof installed in 1987 which contained 15% chrysotile, and other is a residential roof installed before 1983 which contained 12% chrysotile. The concentrations of asbestos fibers in air surrounding asbestos-cement slate roofs and in falling water harvested from same roofs on rainy days ranged from 0.0012 to 0.0018 f/mL and from 1,764 f/L to 10,584 f/L, respectively. The concentration of inorganic fibers in soil around asbestos-cement slate roofs was from 217 to 348 f/g. With above results, excess lifetime cancer risk (ELCR) for risk assessment of asbestos fibers released from asbestos-cement slate based on US EPA IRIS (Integrated risk information system) model is within 5.5E-06 ~ 6.5E-06 levels which indicates that levels do not exceed the acceptable risk(1.0E-05) recommended by WHO. The asbestos concentration in air, drained rainfall and soil around plant slate roof was higher than that around residential slate roof, but excess lifetime cancer risk (ELCR) from residential slate was higher than that from plant slate. This suggested that enclose and encapsulation of residential roofs have priority in removal policy to minimize exposure risk.

일부 학교 건축물의 석면함유 건축자재(ACM) 특성과 위해등급에 관한 연구

The objective of this study is to investigate the distribution of asbestos containing materials and to evaluate risk assessment method in some schools, Korea. For the survey on ACM risk assessment, we used both EPA AHERA rule and ASTM rule. We investigated 100 schools between January and December in 2010. Detection rate of the ACM according to construction year showed that before 1980's, 1990's, 2000's, after 2000's buildings were 100%, 94.1%, 100% and 62.5%, respectively. Compared with school types, detection rate of the ACM in Kindergarten, Elementary, Middle, High, Special Education schools were 100%, 97.1%, 92.9%, 100%, 80%, respectively. Ceiling textiles contained chrysolite/mixed amosite(2∼8 %) and wall cement flat boards contained chrysolite(6∼11 %). Also, gasket contained chrysolite(16∼17 %), slate roof contained chrysolite(10∼13 %). In this study, risk assessment EPA AHERA rule of ACM showed that all materials were Pool grade. And, ASTM rule risk assessment showed that all materials were Q&M program grade.

공기 중 석면농도 분석시 관상어용 기포발생기를 개조한 장치와 기존의 상업용 시료 채취기와의 성능 비교

Objectives: The purpose of this study is to estimate the applicability of regional sample collection of environmental samples. The concentration of asbestos fibers were analyzed with two devices. One was an existing commercial air sampling pump that has been proved to be accurate and exact, and the other is a remodeled pump for sample collection which was made from an electric bubble generator originally designed for aquarium fish. Samples were collected with the two devices under the same environmental conditions and collection equipment. A comparative analysis of the concentration of ambient asbestos fiber was then performed. Methods: Based on previous research, six farmhouses with asbestos fiber slate roofs known to have high concentrations of asbestos fiber were selected. Using the existing commercial air sampling pump and the remodeled electric bubble generator, four to seven samples were collected each day one meter downwind from the edge of the slate roof at high volume (about 4 L/min) and low volume (about 1.4 L/min). The analyzer responsible for sample quality control of asbestos fibers counted the number of asbestos fibers with a phase microscope. Results: The rates of flow change of the existed sampler and the remodeled pump at high volume were 0.82% and 0.17%, respectively. The rates of flow change at low volume were 3.83% and 1.09%, but there was not significant difference. The rates of flow change are within the error range (<TEX>${\pm}5%$</TEX>) of OSHA analyzing methods. For the high volume sampler, the average asbestos fiber concentration in the air collected by the existed sampler is 6.270 fibers/L and for the remodeled one 5.527 fibers/L, not a significant difference. For the low volume sampler, the average asbestos fiber concentration in the air collected by the existed sampler is 7.755 fibers/L and for the remodeled one 7.706 fibers/L, not a significant difference. The total area of the slate roof of the targeted farmhouse has an effect on the concentration of asbestos fibers in the air from the existing pump and the remodeled one (p<0.01). Conclusions: The sampling function between the existing commercial pump and the remodeled one shows little difference. Therefore, the remodeled pump is considered a pump with a good availability for collecting ambient air asbestos samples.

어린이집 실내·외 석면노출 가능성 조사에 관한 연구

Objectives: Because of its properties such as resistance to heat, chemicals and corrosion; tensile strength; sound absorption; and affordable price, asbestos has been widely used as a building material, fire resistant and retardant, thermal and heat insulator, soundproofing material, 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 a Group 1 carcinogen by the International Agency for Research on Cancer, an intergovernmental agency forming part of the World Health Organization. Children and infants are more at risk than are adults if they are exposed to carcinogens, due to aweaker immunity that has not yet been fully developed. Most childcare centers are operated all day and children tend to spend a great amount of time in the centers. This is why it is important for them to be systematically isolated from environments that may expose them to asbestos. Materials: In order to understand both indoor and outdoor hazards to which children may have been exposed, the study focused on actual surveys of asbestos used in childcare centers, paying special attention to slate-roofed buildings in the vicinity of the centers. Results: A survey of a total of 211 childcare centers showed that the buildings of 18.1% of the centers contained asbestos, with 60.53% of the material being found in classroom ceilings. “Tex” was the most used material for ceilings, making up 89.47% of all ceilings. An outdoor survey showed that childcare centers in Daegu Metropolitan City had an average of 143 slate-roof buildings within a distance of 1km. Conclusions: Buildings housing mainly toddlers, children, teenagers and others more vulnerable to the toxicity of asbestos are not subject to asbestos investigation by law. A legal and practical basis for asbestos control is required for such buildings. In particular, housing materials which contain asbestos in day care centers require asbestos control. GIS should be used to identify the location of buildings with slate roofing materials in the vicinity of daycare centers in order to gauge toxicity of exposure to asbestos caused by potential asbestos friability possibility in outdoor conditions.

Structure and properties of CIGS films based on one-stage RF-sputtering process at low substrate temperature

Currently, Nanjing South Railway Station planning to implement slate roof renovation is integrating solar cell modules into traditional roof materials to generate clean energy. Copper–indium–gallium diselenide (CuIn1−xGa x Se2, CIGS) is one of the most promising materials for thin film solar cells. Cu(In1−xGa x )Se2 films were deposited by a one-step radio frequency magnetron sputtering process at low substrate temperature. X-ray diffraction, Raman, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and electrical and optical measurements were carried out to investigate the deposited films. The results reveal that a temperature of 320 °C is critical for near-stoichiometric CIGS films with uniform surface morphology. Cu-rich phase particulates are found at less than this temperature. The sample deposited at 380 °C gives well-crystalline single-phase CIGS film. Furthermore, the electrical and optical performances of the absorber layer are improved significantly with the increasing substrate temperature.

부산시내 석면슬레이트지붕 건축물로부터의 석면 노출 및 건강위해성 평가

This study was performed to evaluate the asbestos exposure levels and to calculate excess lifetime cancer risk (ELCR) for the risk assessment of the asbestos fibers released from asbestos-cement slate roofing (ASR) building. Total number of ASR buildings was into 21,267 in Busan, and 82.03 percent of the buildings was residential houses, and 43.61 percent of the buildings was constructed in 1970s. For this study, ten buildings were selected randomly among the ASR buildings. The range of airborne asbestos concentration in the selected ten ASR buildings was from 0.0016 to 0.0067 f/mL, and the concentration around no-admitted ASR buildings was higher than that around admitted buildings. The ELCR based on US EPA IRIS (integrated risk information system) model is within 3.5E-05 ~ 1.5E-04 levels, and the ELCR of no-admitted ASR buildings was higher than 1.0E-04 (one person per million) level that is considered a more aggressive approach to mitigate risk. These results indicate that the cancer risk from ASR buildings is higher than other buildings, and systematic public management is required for control of no-admitted ASR buildings within near future.

Guidelines for selecting roofing slate for the restoration of historical buildings and monuments: Two case studies

Slate has been used for centuries as a building material, and many historical buildings and monuments use slate in roofs and structures. When slate roofs must be totally or partially replaced, the structural and aesthetic integrity of the building as a whole must be guaranteed, based on both international criteria for restoration, and on current local legislation regarding historical buildings. For selection of the most appropriate type of slate to use in the restoration of historical slate roofing, we propose the following steps: a) study of the roof's state, b) spectrophotometric determination of the texture and colour of the original slate, c) petrographic study and determination of the weatherability of the replacement slate, and d) location of the original slate quarry area. With all these data it is possible to choose the most suitable type of commercial slate for replacing the original slate. Thus, even in the absence of historical information, with this four-stage process a replacement slate for building restoration can still be selected on clear and justifiable grounds. The present article uses this methodology to examine two case studies of roofing slate restoration.

A Study on the Effects of Dismantling of Asbestos-Containing Slate Roof Tiles on Surrounding Environment

A Study on the Effects of Dismantling of Asbestos-Containing Slate Roof Tiles on Surrounding Environment

Effect of freeze–thaw cycles on the bending strength of roofing slate tiles

Slate is one of the most popular natural roofing materials, because of its ability to be split into large, thin and waterproof tiles. However, while some slate roofs last up to two centuries, others disintegrate after just a few years, a fact which is closely linked to the intrinsic properties of each particular slate. The effect of these properties on durability of slates is closely related to their performance during freeze-thaw cycles, as expressed in the European Standard for Roofing Slate (EN 12326:2005), which details the tests required to market roofing slate within the European Union. This paper examines variations in the bending strength of three varieties of Spanish roofing slate tiles, upon exposure to freeze-thaw cycles. Each variety of slate was divided up into 10 groups of 3 tiles, and then subjected to freezing and thawing (from −20°C to 25°C) in a climatic chamber. Every ten cycles, a group was removed from the chamber, and its bending strength was tested according to EN 12326:2005. Petrographical characterization, porosity, water absorption and P-wave velocity tests were also conducted for each group of slate. In additon, in order to determine the environmental thermal changes that could affect the slate's integrity, the temperatures reached by a slate tile on a roof exposed to direct sunlight were measured over a period of 24months.The results showed variations in the bending strength of the slate as well as other properties measured, including water absorption, P-wave velocity and pore size distribution. These variations are due to the formation of a new microcrack system, a process that is closely linked to the petrographical fabric of the slate. Understanding the behavior and durability of roofing slate under freeze-thaw conditions will help in determining which varieties of slate are best for roofs built in cold regions.

Joseph Priestley House

On a hillside in Northumberland, a white Federal-style mansion with symmetrical wings perches a quarter mile above the Susquehanna River. Crowned with a diamond-patterned balustrade on its slate roof, the house boasts a commanding view of the river’s north branch. Before the canal and the railroad cut across the expansive lawn, travelers arriving at the riverfront reached the house by following a semicircular carriage drive that echoed the arched fanlight above the pedimented entrance. Sparsely ornamented with a frieze board of triglyphs and a Palladian window centered on the second story of the facade fronting the street, the five-bay residence was the eighteenth-century American version of an English gentleman’s country house. In this case, the English gentleman was the famous—some would say notorious—Joseph Priestley: pioneering chemist, political philosopher, and dissenting theologian.