Roofing Sheets Research Articles

Multi-objective optimisation for building integrated photovoltaics (BIPV) roof projects in early design phase

Building-integrated photovoltaics (BIPV) is an excellent renewable energy application for building envelopes. In Australia, BIPV roofing is considered to be promising because of recent major concerns about fire risks of façades. However, the integration of PV into building envelope elements is a complicated process which, if not done properly, may lead to failure of the BIPV system. Therefore, feasible BIPV design solutions need to be examined in terms of life-cycle cost and energy performance from the early design phase of a BIPV envelope project. There have been few investigations of the identification of feasible BIPV design options in the early design phase to enable product selection and parametric tests. This study explores a multi-objective optimization method which formulates feasible BIPV envelope design options which have relatively high energy generation and low life cycle costs to informed decision making. The optimisation process has four segments: data inputs, simulator, optimizer and pareto front based optimised BIPV solutions. The proposed multi- objective optimization process is applied in a BIPV roof application using a case study in Australia with roof sheets and skylights. The results demonstrate seven optimum roof sheet BIPV design solutions and fourteen optimum skylight BIPV design solutions to enable design makers to compare and select the most appropriate. The life cycle cost, life cycle energy, CO2 emissions avoided, net present value, payback period, and levelized cost of energy of BIPV solutions vary based on the BIPV modules, tilt angles and placement locations. The proposed optimization method is a helpful guide for BIPV design professionals to identify suitable BIPV design options in the early design phase instead of relying on rule-of-thumb experience.

Mapping Blue and Red Color-Coated Steel Sheet Roof Buildings over China Using Sentinel-2A/B MSIL2A Images

Accurate and efficiently updated information on color-coated steel sheet (CCSS) roof materials in urban areas is of great significance for understanding the potential impact, challenges, and issues of these materials on urban sustainable development, human health, and the environment. Thanks to the development of Earth observation technologies, remote sensing (RS) provides abundant data to identify and map CCSS materials with different colors in urban areas. However, existing studies are still quite challenging with regards to the data collection and processing costs, particularly in wide geographical areas. Combining free access high-resolution RS data and a cloud computing platform, i.e., Sentinel-2A/B data sets and Google Earth Engine (GEE), this study aims at CCSS material identification and mapping. Specifically, six novel spectral indexes that use Sentinel-2A/B MSIL2A data are proposed for blue and red CCSS material identification, namely the normalized difference blue building index (NDBBI), the normalized difference red building index NDRBI, the enhanced blue building index (EBBI), the enhanced red building index (ERBI), the logical blue building index (LBBI) and the logical red building index (LRBI). These indexes are qualitatively and quantitatively evaluated on a very large number of urban sites all over the P.R. China and compared with the state-of-the-art redness and blueness indexes (RI and BI, respectively). The results demonstrate that the proposed indexes, specifically the LRBI and LBBI, are highly effective in visual evaluation, clearly detecting and discriminating blue and red CCSS covers from other urban materials. Results show that urban areas from the northern parts of P.R. China have larger proportions of blue and red CCSS materials, and areas of blue and red CCSS material buildings are positively correlated with population and urban size at the provincial level across China.

Comparative energy analysis of a laboratory building with different materials using eQUEST simulation software

In the context of global warming and climate change issues, the building sector is one of the major contributors to energy consumption and Green House Gas emissions. In view of this, the building concepts are shifting from the standard structures to the low-energy consumption structures through use of passive and active systems to save energy during the life expectancy of the buildingswithout compromising quality and comfort levels. The main aim of this study is to investigate the passive strategies (by using non-energy strategies) to achieve energy-efficient buildings. The work has been carried out for a laboratory building at Nitte, India. The laboratory with Galvanized Iron (GI) sheet roofing and concrete walls, due to which has an uncomfortable living space, has been used for the study. The US department of energy’s eQUEST (The Quick Energy Simulation Tool) software has been used for the simulations. The results show that it is possible to improve the human comfort to the acceptable standards by using the concept of economic thickness of insulation such as the use of 5 mm coconut pith insulation board on the wall and 5 mm jute fiber below the roof with 0.3 m air gap and also by using low emissivity glass window. The Temperature maintained is 75 to 80 ˚F (24 ˚C to 27 ˚C) for maximum number of hours and relative humidity is found to be in between 40 and 49 percent for maximum number of hours, both of which otherwise used to be much outside these comfortable limits.

A Comparative Evaluation of Rain Water Obtained from Corrugated Roofing Sheets within Awka Metropolis, Anambra State

The objective of this study was to evaluate comparatively the effects of different brands of corrugated roofing sheets on rainwater utilized within Awka metropolis. Different physicochemical parameters were assessed in the rain water harvested using established standard laboratory procedures. The rain water was harvested directly (control) and also collected after passing through the different brands of corrugated roofing sheets (samples). The results showed no appreciable effects on the physical appearance, observable odour, or taste of the water samples compared to the control sample. However, at 30 °C, there were minor changes in the pH. The amount of suspended solids (SS) in mg/100ml, total solids (TS), and total dissolved solids (TDS) found in each of the samples, including the control sample, did not vary. This showed that the corrugated roofing sheet has no significant effect on the SS, TS, and TDS of the rain water harvested within the study area. Iron, zinc, and chloride ions followed a similar trend as SS, with Fe and Zn occurring at non-detectable limits of the instrumentation, while the levels of Cl- ion (3mg/100ml) did not vary in all the samples, including the control sample. The results revealed that corrugated roofing sheets affect the total alkalinity and methyl orange alkalinity of the harvested rain water in the study area greatly but had no impact on their physical appearance.

Use of Rainwater in a Hydroponic Greenhouse

The increase in population in the world is currently generating needs for basic resources such as food and even liquids, resulting in a shortage of food that affects families, likewise, hydroponics as an alternative way to produce food with greater profitability and a lower use of land, water and energy, since the rainy seasons have constantly undergone changes, which have affected the natural growth of crops giving a smaller amount of this which generates losses, for this reason a greenhouse is being implemented (hydroponic) since they are more profitable and easier to control, which makes it an alternative to combat food shortages. To contextualize in the following paragraphs, an alternative method will be shown that allows the collection of rainwater that is used to harvest plants without the need for land through a closed system of 100% use. The system has a recollection of water by galvanized sheet roof capturing rainwater and storing it in 3 tanks with a capacity of 20L. They are connected in series which will replenish a 150L capacity tub containing tilapia fish. The tilapia´s waste will allow the vegetables to be nourished by means of a pump. It is proposed to use a hydroponic greenhouse, to grow vegetables and use the waste of the wall as fertilizer since the physical and chemical factors of the water du0072ing the activities of hydroponics and recirculation aquaculture, mainly in relation to the amounts of macronutrients, is undoubtedly the accumulation of nutrients dissolved in the water and helps in the cultivation of tomatoes, lettuce, slices, and cilantro, thus reducing water consumption and contamination of the land.

Production and Testing of Mechanical Property of Roofing Sheet and Paving Block from Plastic Waste, Sawdust and Fine Sand

This study is aimed at producing roofing sheets using local waste materials High Density Polyethylene (HDPE) and Low-Density Polyethylene (LDPE) plastic waste, sawdust and sand). The study was carried out basically for the sustainable use of raw materials in finding a good substitute, which have good tensile strength, and poor heat conductivity thereby reusing waste materials to reproduce new and useful roofing sheets. Laboratory experimental procedure was used for the production of the composite roofing sheet. The result shows that zero percent water absorption was obtained for the roofing sheet. Universal material testing machine was used to test for the compressive strength which gave a range of (6.6 – 144.7) KN/m 2 . The materials showed good potential as a source of roofing sheet, when compared to the industrially made asbestos roofing sheets, with compressive strength ranging between (2.2 – 2.7) KN/m 2 . The strength of the produced composite roofing sheet was found to be between 3 to 20 times higher than the commercial asbestos roofing sheet. However, the paving blocks result showed percentage water absorption of 4.2 percent after immersion into water for twenty-four hours. Universal material testing machine was used to test for the compressive strength, which gave a range of (5.4 – 65.2) KN/m 2 when this result is compared with concrete pavement compressive strength as reported by other workers of (0.048 – 3.56) KN/m 2 the strength of the produced composite paving blocks is 20 to 100 times higher in strength than the concrete paving blocks.

Thermal and lighting evaluation in light roof prototypes, for hot humid climates

The zinc sheet roof is one of the most popular elements in Latin American architecture, and in many other regions with warm humid climates. Creating lighting and thermal alternatives focused on this typology would imply major benefits in the environmental and social fields. This study carried out in Manabí, Ecuador, evaluates three prototypes of light roofs, combining zinc with PVC, in order to determine the correct configuration of translucent material to create environments that are within thermal and lighting parameters. The results indicate that the empirical solutions model has the lowest variation in indoor temperature, with 32.63%, unlike the 32.97% of the cross-type model, and the 34.40% of the side strip model. Additionally, it was seen that the greatest influence of solar radiation on the roof is recorded from 1:00 p.m. to 2 p.m. approximately

Corrosion resistance of galvanized roofing sheets in acidic and rainwater environments

The galvanization of steel sheets for building roofs and construction of additional structures has been a valued solution to the challenges faced by the deterioration of roofing steel sheets in an unfavourable surroundings. This research was conducted on galvanized roofing sheets obtained from the open market in Nigeria. The samples were cut to a small size (5 cm by 4 cm) and immersed in sulfuric acid (H2SO4) and hydrochloric acid (HCl). As the control medium for the experiment, rainwater was used. The experiment was performed over 1200 hours; each sample was removed every 240 hours, thoroughly washed, dried, and weighed again. Based on the reacting media, variations in the weights of the samples were obtained. According to ASTM G1-03 standard practice, Corrosion rates were calculated for preparing, cleaning, and evaluating corrosion test specimens. Scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) was also carried out. Although some samples resisted corrosion, other samples corroded. It is predicted that the green-coated samples are more resistant to corrosion in rainwater and H2SO4 and thus more stable.

Potential Applications of Vitrified Slag as a Product of Plasma Arc Melting

The present article presents the potential of vitrified slag, one of the products of plasma arc melting, for further industrial applications based on previous experiments. The existing publications on the investigation into this field is hence supplemented with our series of experiments conducted using vitrified slag from plasma arc gasification and melting of fly ash from municipal waste, as well as a mixture consisting of fly ash produced by fluidised-bed boilers in a heat power plant and recovered asbestos cement roofing sheets. It should be noted that the process of plasma arc gasification and melting facilitates not only a significant reduction of the quantity of processed hazardous wastes, but also a possibility of transforming such wastes into an inert product, which may be used as an input raw material in certain industrial processes.

Question of Authenticity of Steel Sheet Roof Cover on Traditional Housing Units in Urban Environment

Elaborating on the theory of analytical philosophy and conservation doctrine, and a case study of a selected sample, the paper discusses the authenticity of the secondary roof cover of steel sheets on traditional Bosnian houses built for housing or economic purposes. Although such steel sheet replica of a shingle or šimla wooden cover is registered and defined as authentic in rural areas, its authenticity in urban traditional areas, where it can also be found, although not as often, has not been doctrinally examined. Comparative analysis of results of theoretical base and statistical data obtained from the selected sample determines the context where it is possible and recommendable to treat the steel sheet roof cover as authentic when carrying out restoration and reconstruction.

Simulation studies on corrosion of stone coated roofing sheets sold in Nigeria

ABSTRACT. Acid rain condition were simulated on three selected stone-coated roofing sheets sold in Nigeria to assess the rate of metallic dissolution using (0.25, 0.50, 0.75, and 1.00 M) concentration of sulfuric acid, simulated acid rain (0.5 M of HCl, HNO3 and H2SO4) for 30 days in a controlled environment. Six metals (Pb, Fe, Zn, Al, Si, and Cd) concentration were determined using same concentration of sulfuric acid and distilled water for three hours at elevated temperature of 55 ºC. The results showed that as concentration increases across the three samples, the corrosion rate of stone-coated roofing sheets increases. The analysis of variance (ANOVA) showed that the weight loss of the samples were significant by all input variables. The fourth order polynomial model conducted for weight loss and corrosion showed best fit with regression (R2) which ranged from 0.95 and 0.99 across three samples except for 1.00 M of sulfuric acid at 0.8953, 0.8862, and 0.8933 for Sample 1, 2 and 3, respectively. Metal dissolution conducted for three hours showed that zinc had highest dissolution across different concentration, followed by iron respectively, aluminum dissolved at 0.75 M sulfuric acid; lead dissolved at 0.25 M, 1 M and distilled water while silicon and cadmium had relatively low dissolution accordingly. Acid rain has negative impact on corrosion stone-coated roofing sheets thus influencing its lifespan and durability.
 
 KEY WORDS: Simulation, Acid rain, Metal dissolution, Corrosion, Stone-coated roof, Nigeria
 
 Bull. Chem. Soc. Ethiop. 2021, 35(2), 461-470.
 DOI: https://dx.doi.org/10.4314/bcse.v35i2.18

Investigation of Microbiological Quality Changes of Roof-Harvested Rainwater Stored in the Tanks

Rainwater has been found to be a valuable source of drinking water in Europe, especially in such crisis situations as those caused by contamination of water uptake into water supply systems, large-scale floods or terrorist attacks (e.g., biological weapons). The microbiological quality of water plays a significant role, which is directly related to the potential health risks associated with harvested rainwater (including rainwater stored in the tanks). Microbial contamination is commonly found in rainwater. However, in the literature, detailed results of qualitative and quantitative microbiological assessments are sparse and remain unexplored. Therefore, the aim of this study was to investigate and analyze changes in the microbiological quality of roof-harvested rainwater stored in the tanks, depending on the collection conditions (type of roof surface), storage duration and season. Authors elucidate that conditions such as storage duration, the season in which rainwater is collected, the roof-like surface types and morphology of the catchment area highly affect rainwater quality. This study showed that rainwater harvested from a galvanized steel sheet roof had the best microbial quality, regarding the lowest number of bacteria, while rainwater from a flat roof covered with epoxy resin was the worst. Further, it was detected that rainwater collected in autumn and spring obtained the best microbiological quality. Moreover, a decrease in the number of bacteria was observed in correlation to storage duration. The water became sanitary safe after six weeks of storage at 12 °C. Its use for purposes requiring drinking water quality before six weeks of storage required disinfection.

Effect of fibre reinforced plastic (FRP) roof on performance of lactating Jakhrana does

Present study investigated the use of fibre reinforced plastic (FRP) sheet roof as alternate roofing material in goat shelters. Twenty lactating goats, 10 each, housed under pen having cemented sheet roof (CR) and FRP sheet roof (PR) were managed uniformly during winter. Analysis of data revealed that microclimate and physiological responses of does were similar and does were equally comfortable. The milk yield was significantly lower up to 30 days, recorded lower trend up to 60 and 90 days of lactation in does housed under PR than does under CR. The overall mean weekly test day milk yield and body weight of does recorded under PR was significantly lower than does under CR. Results indicated that the provision of FRP roof as alternate roofing material in goat shelters in semi-arid areas may not be beneficial in increasing production of lactating goats during winter.

Rented apartments an alternative shelter: characteristics and quality across the residential densities in the ancient town of Ile-Ife

PurposeThe study had examined the dynamism in rental housing characteristic in Ile-Ife, Nigeria.Design/methodology/approachData were collected through questionnaire administration on 550 tenants selected across high, medium and low density areas, using systematic random sampling.FindingsFindings revealed that rented apartments in the traditional town are built with modern materials like sandcrete blocks, cement, corrugated roofing sheet and aluminium. Further findings revealed a statistical significant variation in the rental housing typologies across the residential densities (χ2 = 94.732a, df = 10 and p = 0.000). The dominant housing typology in the low income earners areas is rooming apartments known traditionally as (face-to-face), in the middle income earners areas detached and semi-detached bungalows (Mini, 2bedroms and 3 bedrooms flat); and lastly, bungalows and duplexes dominates the high income earners areas. Therefore, the study likened the variation across the income areas to deferential in socioeconomic characteristics of tenants, surroundings peculiarities and the landlord and tenant relationships.Originality/valueThe outcome of this study could strengthen policies in creating design standards for construction of housing for renters; this is step towards achieving Sustainable Development Goal (SDG) 11, creating an inclusive communities.

Comparative study between stressed skin effect of trapezoidal sheet and sandwich panel roof cladding

AbstractPrevious research studied the stabilizing effect of sandwich panel roof cladding and trapezoidal sheet cladding, considering pitched roof portal frame structures. It was observed that these cladding types contribute to the transfer of horizontal loads to the main structural elements, acting in a similar manner as roof bracings, while also providing significant lateral stability to the steel members. Certain methodologies were developed in order to introduce this effect into a 3D numerical model while taking into account the connections between the cladding and the purlins, as well as the influence of the fixing method between the purlins and the main structural members. The current study presents two procedures in order to achieve this and aims to present a comparison between these cladding types in terms of sway displacement of the frame structure with semi‐rigid joints and load transfer by applying the developed methodology to a reference building. The comparison is based on detailed analytical and numerical calculations, carried out by combining the design recommendations available for each cladding type and the developed analysis procedures using a 3D structural analysis software. The analysis results emphasize significant stabilization effects on the structure in both cladding cases.

Assessment of Excess Gamma Dose Exposure Level in Typical Nigeria Commercial Building Materials Distribution Outlets

The gamma dose rate exposure levels from different brands of building materials at commercial distribution stores/shops in two major cities in Ondo State, Nigeria, were measured using a well calibrated Inspector 1000 scintillator detector. The results showed that the different brands of building materials which are Corrugated iron sheet, Aluminum roofing sheets, Conduit pipes, Paints, Cement, PVC pipes, Wash hand basin, Bath tub, Water closet, Kitchen zinc, Asbestos, Floor tiles, Wall tiles, Bullet proof door, Binding wire, rings and rods, Red bricks, Galvanized pipes, Copper pipes, Water tanks contributed excess annual effective doses of 0.332 mSv/y and 0.311mSv/y to store keepers in Ikare Akoko and Akure cities respectively. The indoor and outdoor annual effective dose of each of the investigated two cities are correlated using simple linear regression equations. The results of the modeling and experiment show that annual effective dose received by the occupants of these shops/stores was about 12 % higher than what could be received in a typical natural radiation environment in the two cities because the building materials acts as a source of radiation indoor. The research indicated that the typical habit of using poorly ventilated and confined space as stores/shops by the sales men might subject them to internal exposure through inhalation of radon gas and its short-lived decay products. Implementation of the developed equations would definitely promote rapid determination of outdoor annual effective dose through indoor annual effective dose and ultimately save time and other valuable resources.

Analytical Behaviour of Coconut Coir Roofing Sheet

In world wide the ever increasing population in most developing countries and the corresponding increase in demands and need for infrastructural development, there is an urgent need to focus attention on low-cost alternative construction materials. Lignocellulosic fibers from green coconut fruit were dried under suitable conditions. After this, mixture of phenol cardanol formaldehyde resin and hardener are added to the fiber for binding purpose. Then it is impacted and compressed between two corrugated sheets, in order to obtain the shape of the roofing sheets, for 12 hours. After 12 hours of drying, it is then subjected to various tests such as tensile test, flexural test, impact test, compression test, and hardness test. The results are tabulated in order to compare it with GI sheet and asbestos cement sheet. This coconut coir roof sheet can be replace the former roofing sheets because of its durability, high strength, heat resistivity and low cost which i have been collected data from literature survey. The choose of this alternative is based on economic interest because it is very cheap, available with good mechanical properties, and also based on environmental interest because it is eco friendly. Thus this review paper addresses the characterization and performance of the coconut coir roofing sheet.

An investigation into the feasibility of normal and fibre-reinforced ultra-high performance concrete multi-cell and composite sandwich panels

Inspired by the concept of box girders and bubble deck systems, the present study investigates and develops new forms of composite structures and their behaviours are investigated. The sandwich system implements two basalt fibre-reinforced polymer (BFRP) mesh reinforced ultra-high performance concrete (UHPC) plates as face sheets and a combination of normal strength mortar (NSM) and expanded Polystyrene (EPS) foam as core layers in varying configurations. The box-cell system is produced by UHPC cast into galvanised steel roofing sheet profiles with anchor screws and EPS foam positioned in-situ to produce a box-celled panel. Both systems have three variations for which the structural responses of these panels as one-way slabs under three-point flexure are studied. In addition to the experimental investigations, the sandwich panel theory (EST), advanced sandwich theory (AST), segmental sectional analysis and finite-element analysis are applied to predict the behaviour of the panels at their serviceability limit states. The findings indicate that partially replacing the core with EPS in the sandwich system can effectively reduce the self-weight of the slab without compromising its load capacity under flexure. Moreover, the box-cell system is the most effective when steel fibres are added to the UHPC mix by increasing ductility and preventing early delamination of the steel profile from the UHPC. The modified EST, AST, and sectional analysis can successfully simulate the behaviour of the composite panels within their linear elastic material conditions and the finite-element analysis can accurately model the full-range behaviour of the box-cell composite panels.

Sustainable geopolymer composite reinforced with sisal fiber: Durability to wetting and drying cycles

In Brazil, the sludge generated in water treatment plants (WTPs) has no economic value and since it is composed of silicon and aluminum oxides, it can be used in the production of geopolymers - alternative binders. Sisal fibers are renewable natural resources and relatively inexpensive. With such materials, a geopolymeric composite was produced, and was evaluated for its durability, flexural strength and microstructure. Durability was assessed through accelerated aging (10 wetting and drying cycles). While the reference composite (0 cycles) reached strength values of about 15 MPa in the flexural test, the aged composite reached the strength of 11 MPa, which indicated good durability to wetting and drying cycles. Samples that were naturally aged for 3 years were evaluated using stereomicroscopy. Considering that there was little degradation in the fibers of the composite, it follows that this material could be used in the manufacture of durable roofing sheets.

Prediction and Performance Investigation of Polyurethane Foam as Thermal Insulation Material for Roofing Sheet Using Artificial Neural Network

The prediction and application of Polyurethane Foam in developing roofing sheets cannot be over-emphasized when considering the environmental changes coursed by thermal radiation. This paper presents an artificial neural network application to model and predict the indoor temperature resistance of polyurethane (PU) roofing in residential buildings. The study employed a data logger to measure the indoor and outdoor temperatures for three simulation environments (i.e., morning, afternoon, and evening) for two hours each. Furthermore, the authors employed the Levenberg-Marquardt algorithm to transform and predict the indoor temperature obtained in the residential building's polyurethane roofing house. The result shows that the PU roofing system could absorb the heat and reduce the house model's temperature with 6.9% in the morning, afternoon 15.8%, and 6.8% in the evening when compared with the temperature outdoor environment. The ANN was also able to train, test, and validate the experimental temperature results with 92.86%, 93.92%, and 95%, respectively. The mean square error and a testing error occurs at 0.1707 and 0.1689. Therefore, this study concluded that ANN's application in predicting the thermal insulation material such as the PU roofing system is highly efficient and will increase the manufacturer's performance evaluation. It has also created significant awareness of the community in employing the PU roofing system for residential buildings, which will reduce the rate of energy consumption in buildings.