Roof Design Research Articles

Development of Psi Factors for Thermal Bypass Due to Insulation Gaps in Low-Slope Roofing Assemblies

In commercial roofs, the presence or formation of gaps could be due to improper installation, thermal expansion, and dimensional changes in the insulation boards. The heat loss from these gaps could lead to higher thermal transmittance in the roof assembly. The current research study conducted around 70 experiments to investigate the effect of gap height, gap width and gap offset on the thermal transmittance of the roofing assembly. The measured data showed that in a staggered insulation layout with a joint offset of 610 mm (24 in), formation of 6.4 mm (1/4 in) to 12.7 mm (1/2 in) gaps at the insulation joints could contribute to an average decrease of 2% to 9% in the effective R-value of the roof assembly. As the insulation thermal resistance increases or becomes thicker, the thermal losses in the roof assembly increase. Generalized gap impact curves were developed to provide the relation between gap parameters (i.e., gap widths and height) and the thermal performance of the roof assembly. The experimental data were further analyzed using the psi factor approach of linear thermal bridging generating thermal transmittance data to support the calculation of thermal bypass from gaps in the thermal roof design.

INNOVATIVE POLYMER MATERIALS - IDENTIFYING THE PROBLEM IN A SOCIOLOGICAL SURVEY

The use of innovative building materials is a topical issue in modem construction. A sociological survey was conducted on the objectives of the study. The use of ETFE films is based both on the possibility of implementing almost any ideas of designers and architects in the design of facades and roofs of various structures, and on the specific features of this fluoropolymer. The characteristics are presented and the advantages of this polymeric material are substantiated. Innovation in construction is an innovation that provides a qualitative increase in the efficiency of the processes of erection or operation of buildings and structures. The construction membrane technology based on the use of a composite polymer material-ETFE film (ETFE - ethylene tetrafluoroethylene or ETFE - ethylene tetrafluoroethylene, or partially fluorinated copolymer of ethylene and tetrafluoroethylene) has a set of advantages compared to traditional technologies. The use of innovative building materials is a topical issue in modem construction. A sociological survey was conducted on the objectives of the study. The use of ETFE films is based both on the possibility of implementing almost any ideas of designers and architects in the design of facades and roofs of various structures, and on the specific features of this fluoropolymer. The characteristics are presented and the advantages of this polymeric material are substantiated. Innovation in construction is an innovation that provides a qualitative increase in the efficiency of the processes of erection or operation of buildings and structures. The construction membrane technology based on the use of a composite polymer material-ETFE film (ETFE - ethylene tetrafluoroethylene or ETFE - ethylene tetrafluoroethylene, or partially fluorinated copolymer of ethylene and tetrafluoroethylene) has a set of advantages compared to traditional technologies.

Double Diffusive Convection Heat and Moisture Transfer Inside a Planted Roof Building Under Hot Humid Climate: Case of Lomé City in West Africa

Planted roofs have been investigated as a passive cooling technical for the energy efficiency purpose in buildings. More quantitative data on this topic are required to solve a lack of information for many specific regions. This study is focused to a numerical investigation of the thermal comfort inside a green roof rectangular ventilated cavity in a hot and humid climate as the one of Lomé in west Africa. The left vertical is heated and partly saturated with water to provide humidification of the indoor air. Transfer dimensionless equations are solved using an implicit finite difference scheme, Thomas algorithm and the Gauss Seidel iterative method. We analyze the effects of inlet airflow on the thermal process inside the ventilated and planted enclosure have been investigated. The comfort temperature range deduced from data is: 25°C< Tc < 27°, that of the indoor air humidity is: 49% < Hr <60%. The different ranges obtained are significant and lead to improve inside thermal comfort. The solar flux 350 W.m-2, the average value in case of Lomé city, was used to establish a heat transfer correlation to predict heat transfer through the roof with a relative error not exceeding 4%. This model can be very useful for engineers in the design and optimization stage of a green roof in practical buildings.

Determination of the methodology for the selection of alternative plant species for sustainable green roof design

It is known that green roofs mitigate the negative effects of climate change and environmental changes in cities. The paper presents research related to the determination of the methodology for the selection of autochthonous plant species of the flora of Serbia that would find application in the design of green roofs. The area of city of Belgrade was considered a pilot area. In order to achieve the set goal, the basic climate characteristics of the Belgrade area were considered, as well as the ecological and morphological characteristics of the plants, using the appropriate methodology. Based on the set criteria, a list of autochthonous plants of the flora of Serbia that could be used for the design of green roofs was proposed. When choosing plant material, care was taken to select different groups of plants: annual, biennial, and perennial plants, grasses, and succulents, considering that each of these groups of plants contributes in different ways to the stability and decorativeness of the green roofs.

Design of green roof for an energy efficient university campus

Nowadays, due to the global warming and climate change, many adverse effects and changes are going on in the Environment. Industrialization further worsens the environmental degradation and the air quality. Especially, the construction industry contributes higher level of air pollution emanating from the construction sites. To mitigate this adverse situation, a step towards the green infrastructure may be the best solution. This study was carried out at the Panvel node of Navi Mumbai in the Amity University campus area. The study area was delineated using the Google Earth Pro software. The green roof design and cost estimation was carried out for the main building, new boys’ hostel and new building block at the Amity University campus. Extensive green roof design was proposed for the main building and the new boys’ hostel and intensive green roof design was proposed for the new building of Amity University Mumbai campus. Sedum plant was suggested for the construction of green roof in the main building and the new boys’ hostel and Rosemary shrubs were recommended in the main building. Apart from this, any other shrubs like hibiscus plants or any other flower plant can be used to enhance the aesthetic value. The total runoff reduction was found maximum in the new building roof area and estimated as 5524.81 m3 and the design cost was estimated as Rs.26,73,000 for the main building. The water retained due to green roof will help in reducing the temperature and also improve the air quality in the surrounding area.

Simulation Modelling of Roof Design of Indonesian Airport Terminal For Optimal Utilization of Cooling Energy

The airport terminal is one of buildings with complex energy needs. Most of the airport terminals in Indonesia are designed with regional architectural features, such as pitched or joglo roofs and exterior wall materials made of brick with paint finish. The new airport is designed with modern architectural characteristics with flat and curved roofs and outer walls made of Aluminum Composite Panel (ACP). The difference of shape, material, and the size of fenestration affects the thermal performance of the building and affects the cooling energy used. The purpose of this study is to evaluate the influence of roof designs on airport terminals in Indonesia that have different characteristics on the use of cooling energy. The effect of roof design on cooling energy analyzed by using Design Builder simulation. The simulation results show that the combination of red tile pitched roof and flat concrete roof with insulation in airport terminal building with Indonesian characteristics has the lowest cooling energy performance.

Zoysia Soil-Less Green Roof’s Performance: A Life Cycle Assessment

Abstract The use of green roofs is demonstrated to improve the energy performance of buildings, increase biodiversity, reduce environmental impacts of urban areas, and mitigate climate change phenomena. Their use on a large scale is desirable in the coming years. Still, the choice of the most suitable green roof design solution should also consider the impacts of their production. Within this study, the Life Cycle Assessment methodology was used to evaluate the environmental impact of a particular typology of soil-less green roofs ideated by an Italian company. In this lightweight green roof, the growing medium is replaced by recycled felt layers, filtration is guaranteed by geotextile, and a closed-loop sub-irrigation system fertilises the pre-growth lawn placed on the top. The extremely low weight of this system suggests an optimal use in building retrofitting scenarios, but its environmental implication was not known. The environmental impact of this product has been assessed with an attributional cradle-to-gate approach through four different methodologies (ReCiPe midpoint and endpoint H V1.1, Ecological footprint V1.01, and IPCC 2013 GWP 100y V1.0) using the ecoinvent v3, Agri-footprint 1.0, and ELCD database on the SimaPro 8.4.4.0 software. The IPCC method has shown a Global Warming Potential of 7.66 kg of CO2 eq. for 1 m2 of Pratotetto® green roof; however, the reuse of waste materials from the textile industry must be considered.

Finite element analysis to enhance the efficiency of the secondary roof of double skin roofs (DSRs)

The significant side effect of rapid urbanization in developing cities is urban heat island (UHI), resulting in elevated ambient air temperatures. This causes a further increase in the indoor air temperature of a building bringing thermal discomfort to the inhabitants. It is a well-established fact that the significant electric consumption in buildings creates thermal comfort conditions for the inhabitants. Cool roofs are one of the promising passive technologies to curb the entry of heat flux into the buildings through ceilings, and a double skin roof (DSR) is a cool roof technique in which an air channel inhibits the heat flux entry. This paper presents an opinion to increase the efficiency of the secondary roof of a DSR by providing perforations and fins (extended surfaces) to it by way of a simulation using Ansys software, a finite element analysis software, and incorporating constant peak ambient boundary conditions on the roof for five hours to obtain the temperature distribution. The simulated results show that such a secondary roof design is 16.43 % more efficient in decreasing the temperature at its lower surface than the conventional one.

Effective roof design for the universal gym

The article presents the optimal design of a metal truss designed to cover the roof of a universal gym of size 12x24 m. Trusses made of sloping welded profiles have been shown to be more efficient than traditional double-angle trusses currently used in industrial building roofing. As an example, 24 m arched farms were designed and working drawings were developed.

An experimental investigation on passive and hybrid roof cooling systems with a double skin envelope

ABSTRACT Indoor air temperatures and energy consumption of residential building is increasing at an alarming rate. The design and development of passive and hybrid roof cooling systems with effective cooling techniques play a vital role in improving the thermal performance especially in arid regions. This study investigates the energy efficiency of five laboratory models of double skin passive and hybrid roof cooling systems. A comparative study on the thermal performance of these five systems reveals a highest 14.5°C (41%) and 69oC (79%) reduction in the room and roof surface temperature with double skinned evaporative cooling roof system with forced convection. Similarly, significant reduction in room air and roof surface temperatures are also observed with the other types of double skin passive and hybrid roof cooling systems in comparison with the reference system. The studies have conclusively proven that the double skin passive and hybrid roof cooling systems can appreciably reduce the indoor air and roof surface temperature of residential and commercial buildings. Abbreviations RM: Reference Model; SAV: Standard air ventilated; CAV: Composite insulator air ventilated; FAV: Cooling fan air ventilated; EAV: Evaporative cooling air ventilated; ERAV: Evaporative cooling with radiation reflector Air ventilated

Socio-Ecological Dimensions of Spontaneous Plants on Green Roofs

Green roofs have the potential to provide socio-ecological services in urban settings that lack vegetation and open space. However, implementation of green roofs is limited by high construction and maintenance costs. Consequently, green roof projects often disproportionately benefit wealthy communities and can further marginalise disadvantaged communities by increasing property values and housing costs. Vegetation cover on green roofs is crucial to their provisioning of socio-ecological services. Evidence suggests that green roof plantings change over time, especially with limited maintenance, and are replaced with spontaneous “weedy” species. This is often perceived as a failure of the original green roof design intent and spontaneous species are usually removed. However, where good coverage is achieved, spontaneous vegetation could provide beneficial services such as stormwater mitigation, habitat provision, and climate regulation. While social norms about “weediness” may limit the desirability of some spontaneous species, research suggests that their acceptability on green roofs increases with coverage. As spontaneous species can establish on green roofs without irrigation and fertiliser, reduced input costs could help facilitate adoption particularly in markets without an established green roof industry. Construction costs may also be reduced in hot and dry climates where deeper substrates are necessary to ensure plant survival, as many spontaneous species are able to colonise shallow substrates and can regenerate from seed. If implemented based on socio-ecological need, green roofs with spontaneous vegetation coverage may apply less pressure to property values and housing costs than conventionally planted green roofs, increasing the resilience of urban communities while limiting gentrification.

The flyash addition on Al 5xxx series alloys prepared by die cast and examine its surface by radiographic method

Al 6063 is silicon/magnesium based 5 series alloy which is having more heat capacity, able to withstand in high temperature and also good surface finish. It has wide applications such as making of window frames, roof designs etc. Aluminum alloy 6063 was made with suitable bearings of strong power of tension and extreme molding ablity.it will have more mechanical properties while adding reinforcements like Titanium carbide, silicon oxide, Flyash and aluminum oxide etc. in this research work, AA 6063 reinforced with flyash particle that was produced by sand and die casting techniques with and without heat treatment. The metal matrix composites structural behavior has been examined with support of NDT and DT approaches. The results of the inspection reveals that die casting samples which contributing well in structure and bondage of aluminum alloy with flyash at high level when it was a comparison of sand casting. Finally the hardness (49 HV) and impact strength (8 J) are very high on die casting along heat treated.

Hydrological Performance of Green Roof Systems: A Numerical Investigation

Green roof systems could help reduce peak discharge and retain rainwater in urban areas. The objective of this study was to investigate the hydrological behavior of a green roof system by using the SEEP/W model. The rainfall-runoff relationship within the green roof system was simulated and the results were compared with actual data from a test bed for green roof systems to verify the applicability of SEEP/W. Then, the verified SEEP/W model was used to simulate the green roof system by varying four factors (soil type, rainfall intensity, substrate depth, and green roof slope) to explore the hydrological performance through the peak discharge to rainfall intensity (PD/RI) ratio and the rain water retention rate. The results show that the model presents slightly faster and greater peak time and peak discharge values, respectively, as compared to the observational data. This is attributed to the vegetation conditions in the real green roof system. However, it is also shown that the SEEP/W model can be used to design green roof systems and evaluate their hydrological behavior because of its modeling efficiency. Thus, the SEEP/W model can be used to reliably design and manage green roof systems by further considering the vegetation conditions and water flow dynamics. Furthermore, it would be desirable to consider additional factors, such as vegetation and an insulating pebble layer, in the design and management of green roofs in future work.

Intuitive and efficient roof modeling for reconstruction and synthesis

We propose a novel and flexible roof modeling approach that can be used for constructing planar 3D polygon roof meshes. Our method uses a graph structure to encode roof topology and enforces the roof validity by optimizing a simple but effective planarity metric we propose. This approach is significantly more efficient than using general purpose 3D modeling tools such as 3ds Max or SketchUp, and more powerful and expressive than specialized tools such as the straight skeleton. Our optimization-based formulation is also flexible and can accommodate different styles and user preferences for roof modeling. We showcase two applications. The first application is an interactive roof editing framework that can be used for roof design or roof reconstruction from aerial images. We highlight the efficiency and generality of our approach by constructing a mesh-image paired dataset consisting of 2539 roofs. Our second application is a generative model to synthesize new roof meshes from scratch. We use our novel dataset to combine machine learning and our roof optimization techniques, by using transformers and graph convolutional networks to model roof topology, and our roof optimization methods to enforce the planarity constraint.

Helipad on the building roof design features

The following items are considered: requirements, constructive decisions for helipads; covering plate design of the helipad located on the building roof; helipad modeling in LIRA CAD SP; calculation of a multi-storey building with a helipad on the roof, check for strength and rigidity; characteristics of the helipad on the building roof.

Konstruksi Atap Rumah yang Tanggap Terhadap Pasir Vulkanik pada Kawasan Wisata Gunung Agung di Bali

&lt;p class="Abstract"&gt;&lt;em&gt;&lt;span lang="EN-GB"&gt;The area around Mount Agung needs a roof design that can give extra protection for the residents. The volcanic sand may cause serious danger and damage to the residents' houses since it brings a heavy load to the roof. It causes roof collapses and it dangers the residents' safety. This study was a Research and Development Research and Development by Borg and Gall with a mixed method. Roof testing was done by carrying out an FGD by inviting one expert to provide input on the quality of the product, for revising and reporting the results according to the improvements. Based on the study, it was found (1) the needs of the residents due to the roof design, (2) the suitable type of roof that is resistant to the volcanic sand, and (3) the suitable roof construction for the residents around Mount Agung. The results of the study are expected to contribute to the construction design of residents' houses around Mount Agung that can protect them from the volcanic sand. &lt;/span&gt;&lt;/em&gt;&lt;/p&gt;

A Conceptual Review of the Potential of Cool Roofs as an Effective Passive Solar Technique: Elaboration of Benefits and Drawbacks

Cool roofs, as feasible and efficient passive solar technique that reduces building energy requirements for cooling and improves indoor thermal comfort conditions, have received considerable attention in recent years and as a result, a number of concepts, methods, and experiences have been developed during the related research. Although some studies have been conducted on this subject in the form of review articles, taking into consideration the large number of publications, there is still a call for some review papers dealing with the potential of cool roofs and providing a thorough report on their energy performance and a detailed summary of their pros and cons on the basis of the relevant studies. On this account, this study contributes a systematic review of the issued paper in Scopus and Web of Science regarding the cool roof technologies to recognize the advantages and challenges of cool roofs in practice and its future trends. In addition, detailed summary of advantages and drawbacks of this passive solar measure has been developed, as itemized factors corresponded to the codified references. A total of 90 published reports were analyzed, declaring that a cool roof is an efficient approach for generating clean energy on the building scale. This article induces an overall view of the advantages and restrictions of the cool roof throughout the world. Conclusions give a valuable reference for improving the cool roof design for their more widespread use in the building industry.

Experimental Investigation of the Effects of Helical Roof on the Performance of Stairmand High Efficiency Cyclone

Cost-effectiveness of a standard and a modified Stairmand high-efficiency type cyclone was compared at various inlet gas velocities. The modified design was obtained by replacing the roof of the standard design with a helical roof. Experiments were conducted by both standard and helical roof designs at the same operating conditions. Results showed that helical roof leads to reduced pressure drop in cyclones while having a negative impact on particle collection efficiency. Reductions in pressure drop can reach up to 30%, while particle collection efficiency is reduced by up to 8% simultaneously. Overall, the treatment cost of a cyclone separator can be reduced by 14.1–20.8%. Results indicated that helical roof design cyclones can be used to reduce overall treatment cost by cyclone separators.

Chinese Architecture Evolved with Changes in Snowfall

Roof design in northern China changed over centuries in response to extreme snow events, new research suggests.

EXPERT PANEL ON IN-SITU VISUAL INSPECTIONS FOR MASONRY CHURCHES MAINTENANCE STAGE

The incorporation of protocols in heritage building preservation is important for the definition of preventive conservation actions. Such integration is needed to avoid restoration actions and to promote preventive maintenance instead of corrective maintenance actions. This paper presents the application of an innovative digital management system using artificial intelligence that can quantify the suitability of a sample. This kind of application can support the maintenance management of buildings and minimise human error in data collection. The fuzzy system showed slight differences between the members of the expert panel during the in-situ visual inspection. These results indicate that, despite differences between various experts’ evaluation of a building, the proposed digital method helps minimise the uncertainty in the results. The paper highlights input variables, which present high dispersion (load state modification, fire and occupancy), and input parameters, which present low dispersion (preservation, roof design and overloads). Fuzzy systems can adequately manage the uncertainties associated with different experts’ assessment of sample that present constructive homogeneity. This study can give advantages to stakeholders during the inspection, diagnosis and evaluation stages in the improvement of mitigation policies focused on preventive maintenance programs dedicated to the resilience of heritage buildings, specifically churches emplaced in Chile.