Public perception of fire safety and risk of timber buildings

This paper explores recent developments in timber building designs and its potential towards reducing carbon emissions. Carbon dioxide emissions are a growing issue worldwide as urbanization and industrialization continues to increase. The rising concentration of carbon dioxide emissions pose significant concerns towards public welfare and environmental health. Despite current methods to reduce greenhouse gasses, carbon emissions remain difficult to reduce from steel and concrete industries. Increasing timber use in building design is a possible solution. Increasing more timber in building design can help reduce carbon emissions due to the carbon-absorbing properties of the construction material. Timber as a construction material plays a significant role in modern buildings with a focus towards sustainable design. In this review, a systematic approach was used to find literature that could be analyzed to find which timber building designs would be feasible in mitigating carbon dioxide emissions. It was concluded that both timber and timber-hybrid buildings are effective at reducing carbon emissions. Timber-hybrid buildings are a potential application towards increasing timber in building designs in a way that doesn’t compromise their structural integrity. The most favorable building design that balanced sustainability and structural integrity was the timber-steel building design. However, more studies are needed to further investigate the connection assemblies of timber buildings, as well as implementation of forest management practices to prevent overharvesting of timber. With further development, there can be a balance between technological advancements and environmental welfare.

A risk-based approach for timber building decay prediction

As the population continues to grow in China’s urban settings, the building sector contributes to increasing levels of greenhouse gas (GHG) emissions. Concrete and steel are the two most common construction materials used in China and account for 60% of the carbon emissions among all building components. Mass timber is recognized as an alternative building material to concrete and steel, characterized by better environmental performance and unique structural features. Nonetheless, research associated with mass timber buildings is still lacking in China. Quantifying the emission mitigation potentials of using mass timber in new buildings can help accelerate associated policy development and provide valuable references for developing more sustainable constructions in China. This study used a life cycle assessment (LCA) approach to compare the environmental impacts of a baseline concrete building and a functionally equivalent timber building that uses cross-laminated timber as the primary material. A cradle-to-gate LCA model was developed based on onsite interviews and surveys collected in China, existing publications, and geography-specific life cycle inventory data. The results show that the timber building achieved a 25% reduction in global warming potential compared to its concrete counterpart. The environmental performance of timber buildings can be further improved through local sourcing, enhanced logistics, and manufacturing optimizations.

One of the new trends in the building construction industry is designing for environmental-friendly buildings, a.k.a. Green Buildings. Planners and designers are therefore trying to accommodate these new environmental practices into existing design criteria. Selection of building materials is one of the key decisions need to be made by building designers. However, due to the strong influence of costs on the building industry, making material-selection decisions solely based on their environmental impacts could be both inadequate and impractical. These factors therefore complicate the building design process, especially pertaining to material selection. Accordingly, the present study is aimed at providing much needed support to the decision-making process of residential building design. To this end, the study evaluates and analyzes the environmental and cost impacts of several building assemblies and material alternatives for the building exterior walls. The Technique of Order Preference Similar to Ideal Solution (TOPSIS) is used to evaluate and rank different material alternatives used in walls based on their environmental impacts. In addition, the environmental data used in this study were extracted from commonly used databases that considered the lifecycle impacts of different residential building materials and assemblies. The environmental and cost impacts of several exterior wall assemblies are then aggregated for different building material alternatives to allow for an objective comparison of these assemblies and facilitate proper building design decision- making. The study results show that wood and exterior insulation finishing system (EIFS) provided the best environmental performance of wall structural and wall finishing materials, respectively. This research is expected to prove useful in supporting building design decision- making. In addition, this research can improve pre-construction estimation and support screening of building materials.

Seismic shear and acceleration demands in multi-storey cross-laminated timber buildings

Today’s city centres in European metropolitan areas are comprised of facades made of steel, glass and stone. These hard reflective facades are amplifying the perception of noise sources by human ears in their vicinity. Up to now in building designs this effect is neglected. Thus the number of people harmed by noise is increasing with the increasing noise levels on the streets caused by more and more hard reflective facades. To obtain control on urban acoustic spaces the focus of architects and engineers must be shifted to acoustics parameters. Several case studies in course of this research give evidence for the possibility of controlling the impact of noise sources on an urban space with modified facades. The experience and results of the case studies were merged to deliver a plot of a process chart for implementing the acoustical point of view in a building design process. Laboratory methods e.g. scale model measurements and impedance measurements were modified in order to be feasible in a building or facade design process. As with modified reflection properties of facade surfaces a sound reduction of up to 8 dB for specific frequency bands is feasible the building of quieter cities is in the responsibility of architects and engineers.

Even though there are a number of examples of BIPV, the concept of integration into the building and its design process have not yet been clearly defined. Lack of integration makes this new technology application expensive and very complex to implement. The challenge is how to make this new concept easily applicable and to spread this promising technology for users. In order for PV technology to be added effectively into the design process, full integration is essential. Full integration can be achieved when close interface develops between the PV System and the elements of the building design process. The design process is the spine that links the building from its inception all through its life cycle. The architects, along with the consultants and technical experts, are directly responsible for this process. PV has to be part of the building material and its building material properties have to be equivalent to other conventional building materials. PV has to fit into the building design process from the beginning. As a building component, it has to have certain standards and codes that will fit well within general building codes. This paper starts with the definition of the architectural building design process. It then continues with identifying the barriers that have direct effect on this process. These barriers are lack of interface (integration with typical building process), lack of common language, mismatched potential, unknown performance, and lack of economic analysis. The paper concludes by giving suggestions on how these barriers can be broken.

Hygrothermal performance of buildings is one key element to the sustainable design, health, and comfort of the indoor environment. Building sustainability depends on all associated lifespan stages, from building design and material production to demounting and waste management. Many building materials are unsustainable in terms of their environmental impacts. One approach to reduce environmental impacts associated with buildings is the development and application of bio-based building materials. The aim of this study was to determine the hygrothermal properties of bio-based thermal insulators that promote energy efficiency and contribute in decreasing environmental impacts of buildings. Here, the hygrothermal properties of eight new peat-, recycled paper-, wood shaving-, and feather-based insulation materials were assessed. Measurements of these material properties will improve understanding of the energy efficiency, permeability, and sustainability of new buildings, building retrofits, or both. Data on these new materials will provide the necessary parameters to develop a hygrothermal dynamic numerical model. The studied bio-based materials appear to provide sufficient hygrothermal performance, which is comparable with conventional insulation materials with minimum embodied energy.

This paper’s focus is Russia, a country where trust in police has been low for decades. We examine key factors that explain citizens’ assessments of risk and safety, perceptions of police legitimacy and engagement in precautionary behaviors. We further explore the relationship between gender, prior victimization, and neighborhood incivilities to explain citizens’ safety perceptions. Two key findings emerge from a survey of millennials from St. Petersburg, Russia. Police legitimacy is a strong predictor that is positively related to citizens’ safety perceptions. However, engagement in precautionary behaviors is inversely related to respondents’ safety and risk perceptions. In addition, we have found that being a female is a strong predictor of feeling unsafe, a finding consistent with studies from other parts of the world. Neighborhood incivilities are negatively associated with safety perceptions, but its effect was only marginal for men in the subgroup analysis. Implications for the citizens’ practices of engagement in co-producing safety versus enhancing police legitimacy and the police role in enhancing risk and safety perceptions are discussed.

Mass timber building material in the U.S. construction industry: Determining the existing awareness level, construction-related challenges, and recommendations to increase its current acceptance level

Mass timber building materials such as cross-laminated timber (CLT) have captured attention in mid- to high-rise building designs because of their potential environmental benefits. The recently updated multistory building code also enables greater utilization of these wood building materials. The cost-effectiveness of mass timber buildings is also undergoing substantial analysis. Given the relatively new presence of CLT in United States, high front-end construction costs are expected. This study presents the life-cycle cost (LCC) for a 12-story, 8,360-m2 mass timber building to be built in Portland, Oregon. The goal was to assess its total life-cycle cost (TLCC) relative to a functionally equivalent reinforced-concrete building design using our in-house-developed LCC tool. Based on commercial construction cost data from the RSMeans database, a mass timber building design is estimated to have 26 percent higher front-end costs than its concrete alternative. Front-end construction costs dominated the TLCC for both buildings. However, a decrease of 2.4 percent TLCC relative to concrete building was observed because of the estimated longer lifespan and higher end-of-life salvage value for the mass timber building. The end-of-life savings from demolition cost or salvage values in mass timber building could offset some initial construction costs. There are minimal historical construction cost data and lack of operational cost data for mass timber buildings; therefore, more studies and data are needed to make the generalization of these results. However, a solid methodology for mass timber building LCC was developed and applied to demonstrate several cost scenarios for mass timber building benefits or disadvantages.

Using diary methods, we explored characteristics of young adults’ sexual risk interactions over a 2‐week period and the framing effects indicate in associations between the perceived risk and safety of these sexual risk behaviors. We screened all participants to ensure moderate to high scores on an HIV knowledge measure. Men (n = 44) and women (n = 48) enrolled at an inner‐city college collected diary data, generating reports of 440 sex occasions over a 2‐week period (1,278 person‐days). Despite participation in sexual risk activities, including highly inconsistent condom use during intercourse, participants uniformly reported high safety and little to no risk. Only women's perceptions of safety (not risk) were associated with condom use, men's perceptions of both safety and risk were unrelated. Ratings of safety and risk appeared to operate independently for the most part. Sex with new partners and new sexual activity were associated with both judgments of greater risk and lower safety were associated for men only. These results add to the growing evidence that young people fail to integrate their general knowledge regarding HIV risk into their personal interactions. This study has implications for the development of cognitive models around sexual decision‐making for young adults at risk for HIV and may provide insight into the contextual features of sexual interactions associated with young people's perceptions of risk and safety.

Sustainability impact assessment of glue laminated timber and concrete-based building materials production chains – A Lithuanian case study

The construction sector consumes high amounts of resources and energy while generating significant amounts of waste. This development is contrary to Circular Economy principles, which require buildings that are resource and energy efficient and enable material recycling to the greatest possible extent. To effectively tackle this problem, the EU places a strong focus on sustainable building design. However, to assess this development, indicators that measure the potential recyclability of buildings already at the design stage are necessary. In this study, the “Relative product-inherent recyclability” (RPR) assessment method is applied to evaluate the recyclability of buildings. The RPR method considers buildings’ material composition and structure (assembly) to measure recyclability, thereby describing recycling-relevant factors. The method is based on the statistical entropy approach, which aims to describe material distributions. The RPR increases the more building parts can be disassembled, allowing recovery of concentrated materials. A case study on a timber and concrete building is used to demonstrate the applicability of the RPR metric. The results show that the RPR metric is a suitable indicator for expressing buildings’ inherent recyclability, thus identifying significant differences between building variants. Relevant design optimizations can be deduced from the RPR results. In our case, the timber building achieves higher recyclability than the concrete building. Applying the RPR indicator on the EU level can be recommended and offers significant insights into the design and recyclability of buildings. Architects and constructors could use the metric as a planning and evaluation tool, thereby promoting circular building design concepts.

Due to the associated fire risk, the wildland–urban interface (WUI) has drawn the attention of researchers and managers from a range of backgrounds. From a land management point of view, it is important to identify the WUI to determine areas to prioritise for fire risk prevention. It is also important to know the fire risk mitigation measures available to select the most appropriate for each specific context. In this systematic review, definitions of the WUI were investigated and physical mitigation measures for reducing the risk of fire were examined from a land management perspective. The PRISMA 2020 Statement was applied to records published until 31 December 2022 and retrieved from the Web of Science, Scopus, and other research engines. A total of 162 publications from scientific journals and the grey literature were scrutinised and selected for analysis. Only publications providing an original definition of the WUI or proposing physical measures to reduce fire risk at the interface were retained, while those relating to emergency management and social perception were not considered. The risk of bias was reduced by internal cross-assessment by the research team. Definitions of the WUI (n = 40 publications) changed according to the research objective, varying broadly in identification of the anthropogenic and the wildland components of the interface. Terminology varied according to the definition, and the term wildland–human interface (WHI) was found to be more comprehensive than WUI. Methodological definitions of the interface ranged from using aggregated data through to identification of the buildings at risk in the interface with considerable precision. Five categories of physical fire risk mitigation measures (n = 128 publications) were identified: clearance distances, landscaping, wildland fuel management, land planning, and buildings design and materials. The most effective measures were those applied at early stages of urban development, and maintenance of assets and vegetation is crucial for preparedness. This review represents an analysis of scientific evidence on which land managers can base their actions to reduce the fire hazard risk in the WUI. The number of studies investigating the WUI is considerable, but experimental studies and quantitative results are scarce, and better communication and coordination among research groups and land management agencies is advisable. This systematic review was not registered.