Academic literature on the topic 'Decay of buildings'

Within the built environment, historic buildings are among the most vulnerable structures to the climate change impact. In the Scandinavian countries, the risk from climatic changes is more pronounced and the right adaptation interventions should be chosen properly. This article, through a multidisciplinary approach, links the majority of climate-induced decay variables for different building materials with the buildings’ capacity to change due to their protection status. The method tends to be general as it assesses the decay level for different building materials, sizes, and locations. The application of the method in 38 locations in the Scandinavian countries shows that the risk from climatic changes is imminent. In the far future (2071–2100), chemical and biological decays will slightly increase, especially in the southern part of the peninsula, while the mechanical decay of the building materials kept indoors will generally decrease. Furthermore, the merge of the decay results with the protection level of the building will serve as a good indicator to plan the right level and time of intervention for adapting to the future climatic changes.

Purpose – The purpose of this paper is to set up and analyze a formal model for maintenance scheduling for local government purpose buildings. Design/methodology/approach – The authors formulate the maintenance scheduling decision as a dynamic optimization problem, subject to an accelerating decay. This approach offers a formal, yet intuitive, weighting of an important trade-off when deciding a maintenance schedule. Findings – The optimal maintenance schedule reflects a trade-off between the interest rate and the rate at which the decay accelerates. The prior reflects the alternative cost, since the money spent on maintenance could be saved and earn interests, while the latter reflects the cost of postponing maintenance. Importantly, it turns out that it is sub-optimal to have a cyclical maintenance schedule where the building is allowed to decay and then be intensively maintained before decaying again. Rather, local governments should focus the maintenance either early in the building’s life-span and eventually let it decay toward replacement/abandonment or first let it decay to a target level and then keep it there until replacement/abandonment. Which of the two is optimal depends on the trade-off between the alternative cost and the cost of postponing maintenance. Originality/value – The paper provides a first formal inquiry into important trade-offs that are important for maintenance scheduling of local public purpose buildings.

Reducing building energy consumption is a significant challenge and is one of the most important research areas worldwide. Insulation will help to keep the building’s desired temperature by reducing the heat flow. Additionally, proper insulation can provide an extended period of comfort, leading to reduced building energy requirements. Encapsulated air is the major aspect of most thermal insulation materials. Low thermal conductivity is a good characteristic of thermal insulation materials. Aerogel has low thermal conductivity, so it is suitable for glazing and insulation purposes. This research paper investigates the effectiveness of aerogel as an insulation material in buildings by incorporating a translucent aerogel-glazing system in the window and aerogel insulation in the wall of a building. Experimental investigation of a 10 mm thick aerogel blanket surrounded box was conducted to assess its performance. Additionally, a CFD simulation was conducted, and the results of temperature degradation for the wall showed good agreement with experimental results. Additionally, the CFD simulation of temperature decay was compared between the aerogel-glazed window and argon-glazed window. It was found that the aerogel-glazed window has slower temperature decay compared to the argon-glazed window. The results showed that integrating aerogel in the glazing system and wall insulation in a building has the potential to reduce the building’s energy consumption. Moreover, a numeric simulation was conducted, and showed that the building’s annual energy consumption is reduced by 6% with the use of aerogel insulation compared to fiberglass.

Many former industrial building sites in Sweden have been abandoned and left to deteriorate. Nowadays, there is a large interest to refurbish and retrofit these buildings for other purposes. Commercial and housing developers are attracted to these areas which are often in the outskirts of the city centers. There are several challenges facing architects and engineers to preserve these buildings, also connected to cultural heritage demands. The aim of this study is to propose measures to preserve cultural heritage buildings. A brick building in Gothenburg, on the Swedish west coast, is used as a case study. The building was used for paper production until 2005. After that, it deteriorated quickly after the heating was turned off. The rapid decay affected the hygrothermal performance as well as the load-bearing capacity of the structure. Small scale laboratory investigations of the building materials show a high degree of decay. Measurements of temperature and relative humidity is used to monitor the hygrothermal performance. Observations show that the brick masonry has heavy salt efflorescence and is in need of further protective measures.

This paper provides an alternative narrative of Detroit from one of economic struggle and racial division. It instead discusses other forces at play, focusing on questionable moral standing and its relationship to built form, specifically the city. The paper explores whether a compelling claim on building’s moral use can be established, and in doing so seeks to establish a causal link between moral relationship and the built environment. Moral relationship is established through three main avenues. The first is a brief discussion of Detroit’s history, particularly its history from WWII onward, in order to establish the complex moral context into which this argument is situated. The second avenue provides a concise summary of Stanley Cavell’s moral framework and discusses the conundrum of having moral obligation in the absence of moral relationship. The final avenue is a look to the famous Renaissance Center as emblematic of the moral relationship at play. The resulting form of analysis relies on the premises that buildings can embody the knowledge and agreement required for (moral) relationship, and that buildings are artifacts of moral relationship. The paper concludes that buildings are therefore morally appraisable, which is to say they can be appraised for their moral appropriateness.

Reconstruction of internal plaster in historical buildings belongs to significant and obvious treatment in a landmark area that helps protect irreplaceable cultural resources. Original form of historical buildings has been usually altered over time and alterations are an important part of the building's history. These interventions don ́t often respect the basic function of interior. Results of these changes cause plaster and painting decay, slow air flow and higher air moisture concentration. Computer simulation plays major role in determining places where is necessary to apply surface protection that will preserve the valuable interior surface against negative influences such as high level of moisture, fungus, chemical reactions etc. Abatement of negative influences within historic buildings requires particular care if important historic finishes are not to be adversely affected. Reconstruction of historical interiors should be designed to minimize visual changes to a historic building. Choosing the most appropriate treatment for a historical building requires careful decision making about using of appropriate material for renovation. Using of nanofibers should be minimal modifications to the historic appearance and protect from negative influences.

The opening of the Guggenheim Museum in Bilbao in 1997 heralded the beginning of an era in world architecture defined by iconic buildings underpinned by mediatic exposure and the belief in the power of design to leverage urban conditions. Today, a conspicuous number of such buildings featuring non-standard geometries are experiencing accelerated forms of decay with the emergence of construction defects. This study compares the type of problems encountered in the Jubilee Church in Rome (1996–2003), analysed in previous studies, with the failures of other two contemporary buildings of analogous features, namely: the Palau de les Arts Reina Sofia in Valencia (1996–2005) and the Museum of the Arts of the XXI Century in Rome (1998–2010). The findings of the study show that the accelerated decay of the three buildings shares familiar features and common challenges: geometry of the façade, local environmental factors, labour organisation, and limited regard of maintenance principles. Building on the patterns identified here, the paper suggests structural reasons for their emergence and speculates on the potential benefits deriving from the amplification of the design function.

This paper describes a resonance decay estimation for structural health monitoring in the presence of nonstationary vibrations. In structural health monitoring, the structure's frequency response and resonant decay characteristics are very important for understanding how the structure changes. Cumulative spectral analysis (CSA) estimates the frequency decay by using the impulse response. However, measuring the impulse response of buildings is impractical due to the need to shake the building itself. In a previous study, we reported on system damping monitoring using cumulative harmonic analysis (CHA), which is based on CSA. The current study describes scale model experiments on estimating the hidden resonance decay under non-stationary noise conditions by using CSA for structural condition monitoring.

Leaky buildings are those that show elevated moisture contents of the framing timber, which can subsequently lead to the establishment of fungal and bacterial decay. Prior to this study, the causative agents of the decay in these leaky buildings were unknown, though it was suspected to be one or more species of decay fungi. Therefore, the overall goal of this multi-disciplinary PhD thesis research was to determine the causative agents of decay in leaky buildings of New Zealand in an effort to develop solutions for both their remediation and future prevention. Use of molecular biology methodology and classical mycological techniques based on morphology enabled identification of decay fungi from framing timber and air samples of leaky New Zealand buildings and provided insight into relative importance based on isolation frequency. In most cases, fungi colonising Pinus radiata D. Don were isolated to produce pure cultures. Mycelia from these cultures on agar media were collected to extract DNA. To identify the fungi to the species level, polymerase chain reaction (PCR) with fungal specific DNA primer pairs were performed followed by DNA sequencing of the internal transcribed spacer (ITS) region. Identification was by BLAST (Basic Local Alignment Search Tool) search on sequences in known GenBanks. In total, 421 samples from leaky buildings were processed, predominately untreated P. radiata decayed framing timber and also fibre cement boards and building paper. From these, sixty-eight fungal identifications were made. The only taxa that were isolated with significant frequency were identified as 4 basidiomycete species, as follows, along with the number of times they were isolated from the 421 samples: • Gloeophyllum sepiarium (Wulf.: Fr.) Karst. 13x • Oligoporus placenta (Fries 1865) Gilb. In Ryv.1985 11x • Antrodia sinuosa (Fr.) Karst. 8x • Gloeophyllum trabeum (Fr.) Murr. 4x Although these species were identified repeatedly, in total they represent less than 10% of the total samples and, therefore, it is concluded that the leaky building decay samples represent high fungal biodiversity. An aerial spore study of internal air, wall cavity air and exterior air of leaky buildings was carried out using a Merck MAS-100 instrument which collects spores directly onto selective media plates. Viable fungal aerial spores were detected at every sampling location tested at the leaky buildings, by the criteria of culturing, with a highest mean of 3714 colony-forming units (CFU) per cubic metre found in the cavities of water-damaged walls. This aerial spore study in conjunction with isolation from decayed wood samples from the same leaky buildings enabled identification of G. sepiarium and A. sinuosa at the same test site. The use of carboxymethylcellulose medium further demonstrated the presence of potential cellulose-degrading fungi within and around the location. Overall, the combination of direct sampling of timber and air sampling proved useful for detection of fungal species variability at a multi-unit building. Four decay fungi isolated from New Zealand leaky buildings and two standard control decay fungi (Coniophora puteana and Serpula lacrymans) were submitted to laboratory wood block testing to determine the effectiveness of currently used wood framing preservatives under laboratory conditions before and after a standard leaching regime. P. radiata blocks were treated with water based boron copper azole and solvent based IPBC propiconazole plus tebuconazole (1:1) preservatives and exposed to the basidiomycetes for 12 weeks. Mass loss for the fungal decay-infected samples was recorded of up to 55% for preservative-treated samples, up to 62% mass loss for leached samples and up to 58% mass loss for un-preservative treated samples. Additionally, well defined dosage responses and approximate toxic thresholds were obtained for all preservatives tested. Results suggested that the minimum IPBC retention specified by Hazard Class 1.2 of NZS3640:2003 (0.025% m/m) is on the low side, and demonstrated after the 2 week leaching regime complete loss of efficacy of boron at 0.4% m/m boric acid equivalent (BAE). This PhD research gave a first overview of fungi occurring in New Zealand leaky buildings, and it demonstrated the following key aspects of wood preservation: 1. The isolated test fungus Antrodia sinuosa was more difficult to control with propiconazole plus tebuconazole at retention 0.007% m/m than the known tolerant fungus Oligoporus placenta; 2. Boron at Hazard Class 1.2 retention of 0.4% m/m BAE was not toxic to Oligoporus placenta; 3. Serpula lacrymans exhibited tolerance to the highest retention of 0.06 %m/m tebuconazole plus propiconazole; and 4. Gloeophyllum species appeared susceptible to all wood preservatives. In order to correlate fungal colonisation and wood decay, colonised wood blocks were studied using light microscopy (LM) and field- emission scanning electron microscopy (FE-SEM). Microscopic observations of P. radiata wood blocks following a standard wood decay test of twelve weeks of fungal colonisation by Serpula lacrymans, Antrodia sinuosa, Oligoporus placenta and Gloeophyllum sepiarium revealed that the two microscopic techniques employed were complementary by allowing features such as pit membranes, chlamydospores or S3/S2 compound middle lamella interface to be photographed in greater detail, allowing for more precise analyses and interpretation of key findings, as follows: 1. Brown rot fungi directly target their apical growth towards degraded pit apetures; 2. Reliance on light microscopy and observed birefringence as a tool to record changes in cell wall crystallinity associated with brown rot decay alone could be misleading; 3. Presence of fine (≤ 1 m) to wide (≥ 3.5 m) bore-hole and hyphal size ranges, and nearly unchanged cell wall thickness of all wood/test fungal combinations, confirmed active decay at moderate to late stages; 4. Some ray parenchyma cells for Antrodia sinuosa, Oligoporus placenta and Gloeophyllum sepiarium colonised blocks were intact throughout late stages of decay, outlining that they were not preferentially degraded early in the brown rot decay process, and 5. Presence of bore-holes, clamp and medallion clamp formation and resting spores (chlamydospores and arthrospores) are fungal specific, can aid in their differentiation and identification, and should be recorded during wood decay studies, as especially resting spores are an important factor when planning remediation strategies. In summary, this PhD thesis research provided the first comprehensive investigation into the biodiversity of fungi from leaky New Zealand buildings, identified the dominant species and presented details about their micromorphology and their decay patterns. It also demonstrated substantial differences in efficacy of preservative formulations currently (December 2008) approved for framing treatments in New Zealand and possible deficiencies where framing may be subjected to severe leaching. This study also provided the first comparative analyses of viable fungal aerial spores between leaky wall cavities and the surrounding air environment. Subsequently, this research added to the knowledge of the decay fungal species diversity in and around New Zealand leaky buildings, outlined their capabilities to degrade treated and un-treated P. radiata framing timber and illustrated the efficacy of New Zealand approved wood preservatives for their potential as remedial treatment and future prevention.

Urban decay is among the most urgent problems in Hong Kong today. There are more than 3,000 blocks of building are considered sub-standard and 110,000 families are living in these homes. Despite the Government's immense effort in undertaking its own renewal projects for many years, Hong Kong Housing Society (HKHS) was the earlier urban renewal agent whom was invited by the Government to undertake redevelopment in the urban areas. In light of the rapid ageing of Hong Kong' building stock during the last two decades, HKHS has further assisted the Government with its own resources and expertise by implementing a 10-year maintenance incentive named "Building Management and Maintenance Scheme" (BMMS) since 2005. The BMMS aims at encouraging property owners to improve safety and hygiene of their living environment, it is administrated by HKHS with the provision of professional advice and financial assistance for publicizing proper building management and timely maintenance. HKHS has exerted all its strength to promote the BMMS for seven years, the research is to gauge the effectiveness of HKHS for the achievement and shortcomings in the aspect of offering building maintenance incentives, particular in the launch of BMMS. The evaluation will focus on the three aspects, including the scheme performance, scheme design process and implementation process. An opinion survey was conducted in June 2012 for the data collection purpose and survey results correlates with the goals and objectives of the study are comprehensively discussed in Analysis I & II. The findings show the effectiveness of HKHS in offering building maintenance incentives much depends on what stage does the scheme undergo, whilst the BMMS in general is operated effectively to address the problem of urban decay, with the exception of running it at the outset of the scheme design stage. In the course of time, the recommendations pursuant to the weakness of the BMMS and the highlights in survey findings are drawn up at the end of the study, in order to make the building maintenance incentives more effectively in solving the urban decay problem.
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Housing Management
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Master of Housing Management

Measurements of the external pressure coefficients around open and sealed 1:20 scale models of a low-rise, naturally ventilated building with a gable roof for livestock housing were made in the NRCC wind tunnel. In addition, the internal pressure coefficients were recorded within the open models. All structural configuration changes of the building had an effect on: the external pressure coefficient distributions, calculated and measured internal pressure coefficients, air inlet and outlet zones, magnitude of the local airflows through individual openings, and on the calculated ventilation rate coefficients. As well, there were considerable differences between results for the sealed and open models especially at the ridge level. Generally, the comparisons between the ventilation rate coefficients of the open and sealed model suggest that the larger the total sidewall, end wall and ridge opening areas were, the greater the discrepancies were between open and sealed models' predictions. (Abstract shortened by UMI.)

Rising damp is an almost inevitable and hazardous phenomenon for historic buildings. This phenomenon, which already exists in buildings (to a lesser or greater extent), accelerates when faced with disasters that dramatically increase the water content within the building. While researchers are developing new monitoring methods to examine the effects of rising damp on structures effectively, organizations are designing new risk management plans to minimize the impact of disasters to which cultural heritages are exposed. The case study presented in this thesis includes studies carried out in the Byzantine church of Santa Croce in Ravenna, Italy, which was exposed to rising moisture from flooding due to soil submersion. By analyzing the samples collected from the church, the extent of the decay was determined. Moreover, a new method ensured that the monitoring of moisture in the church was reliable. The data obtained can be used to support the multi-disciplinary studies carried out in the church of Santa Croce, which was selected as part of the EU Horizon 2020 SHELTER project.

The role of bacteria in the decay of building stone from ancient monuments was examined using the framework of Koch's postulates. This involved a stepwise approach to investigate the occurrence, nature and decay potential of bacteria on stone. Prior to investigating the occurrence of bacteria on stonework it was necessary to develop a standardised procedure of high precision for the recovery and enumeration of these bacteria. A number of different methods to remove bacteria from stone were studied including physical agitation, chemical desorption and surfactant treatment. Finally a method was adopted in which stone samples were powdered, homogenised in a dilute solution of surfactant (Tween 80) and counted on an automatic plating system. A range of growth media were used to examine three different bacterial types, namely, sulphur-oxidising, nitrifying and heterotrophic. To investigate the occurrence and distri but10n of bacteria on both sound and decayed stone extensive bacteriological surveys were conducted on stonework at two monuments, Portchester Castle and Tintern Abbey. All types of bacteria were widely distributed on both sandstone and limestone at the monuments. At each monument, significantly more sulphur-oxidising and heterotrophic bacteria were associated with severely decayed stone than undecayed stone. Electron microscopy confirmed that large populations of bacteria could be found predominantly 5-10mm below the surface of decayed stone. Approximately 200 bacteria were isolated into pure culture during the field surveys of the two monuments. All isolates were screened for decay potential using a liquid culture system involving static growth of bacteria in the presence of 1cm stone discs. From the 200 isolates, about 30 were capable of causing substantial weight loss in sandstone discs under heterotrophic conditions. Five isolates were able to cause a large weight loss using only mineral nutrients. Some isolates caused a significant weight gain in the stone discs under these conditions. Statistical analysis of the data from this decay screen indicated that weight loss of stone could be directly correlated to a decrease in pH of the medium and a release of calcium and silicate from the stone. Futher decay studies carried out on selected isolates suggested that under heterotrophic conditions the bacteria secreted quantities of organic acids in to the medium which could attack the stone. However, in the presence of an inorganic nutrient source, the generation of mineral acids may be involved. Under both conditions different stones had varying resistance to bacterial decay and this appeared to be dependent upon the level of calcite in the stone. Specific antibody techniques such as BLISA and FAT were examined and proved very useful in demonstrating the presence of certain principal decay species on samples of decayed stone.

Delays are a common feature of construction projects and frequently lead to disputes between the parties. In resolving these disputes it is essential to have a robust methodology for analysing delays. It is argued that current understanding of available delay analysis methodologies is inadequate and hindered by taxonomic confusion. There is a need for guidance on available delay analysis methodologies and an explanation of how these are implemented, and, as a result, models have been proposed that aid practitioners in the selection of a defendable and most appropriate delay analysis method under the specific circumstances of a project. This suggests an element of choice over the method to be selected: for example, the Society of Construction Law recommended the Time Impact Analysis methodology for undertaking a retrospective delay analysis. The question is whether this or any such methodology is necessarily appropriate. There is general confusion over the selection of delay analysis methodologies. Here, it is proposed that this confusion can be reduced and delay analysis improved by an analysis of the latest research on the status of delay analysis in the UK, an analysis of common law guidance on methodology, an assessment of professional and research literature on delay analysis and research into what is being currently undertaken by experts in the field of delay analysis. This has been done using a mixed methods approach that included: (i) analysis of a questionnaire survey by the CIOB to understand the current state of time management in the UK construction industry; (ii) analysis of the industry guidance on delay analysis methodologies; (iii) a comprehensive review of related English Case Law; and (iv) an analysis of 27 case studies comprising programming expert reports that were presented as evidence in arbitrations. These multiple sources enabled the researcher to ascertain, in the case of each delay analysis methodology: (a) the dominant method actually used in disputes; (b) the details of its application; (c) the reasons for its selection; and (d) its level of accuracy and subsequent acceptability. The research demonstrates that when time claims are accompanied by cost claims there is a dichotomy in the choice of appropriate methodology. There is a clear preference for prospective analysis of time issues, but a retrospective approach for claims that involve finance. At the same time, when a claim contains both elements, the courts appear to prefer a single approach, namely, the retrospective approach. This has resulted in the recommended method of undertaking delay analysis by the Society of Construction Law being not supported by English common law and ultimately to an increase in confusion within the Industry. Given the courts’ fundamental opposition to a method that better accords with forensic logic, it is expedient to recommend a ‘best of the rest’ method for delay analysis rather than adopt a formulaic approach to selecting the appropriate delay analysis methodology. Case study reviews have shown the Windows Analysis methodology is widely used and this is also widely accepted as the most accurate and appropriate methodology, although less well known than other less appropriate delay analysis methodologies. Apart from its theoretical significance, the research should improve construction practitioners’ understanding of delay analysis, and provide clarity on the evidence required to support a claim for an extension of time. It has the potential to reduce disputes over selection criteria and promote harmony between the construction and the legal professions over the appropriate method of resolving delay claims.

The present study firstly aimed to identify children with delayed reading who were missing the component skills of decoding fluency and who also displayed antisocial behaviour in the classroom. It also aimed to replicate with them an intervention designed by Church, Nixon, Zintl and Williams (2005). The study finally aimed to explore the question of whether children who have both a reading delay and a disruptive behaviour disorder require a reinforcement scheme to maintain their engagement in learning activities. Six participants worked with same-age peer tutors on specially-designed practice activities for approximately 20 minutes a day, four times a week, for 8-18 sessions. Improvement in decoding fluency and prose reading fluency was tracked for each child throughout the intervention. Results showed that the six participants gained, on average, sixteen months on their age-equivalent score for reading rate. Decoding fluency scores increased from a pre-test average of 16 correct graphemes per minute to 32 correct graphemes per minute at the post-test measure. Reading accuracy improved by an average of five months and reading comprehension by an average of six months. The gains in reading rate are most likely due to the practice opportunities afforded by the testing procedures as decoding fluency scores did not improve enough to have had a direct impact on the learners’ prose reading ability. Implications for remedial reading interventions with children with behaviour problems are discussed.

This is a methodology of ‘Building Pathology’ explained through theoretically and practically by applying it on a case study. The stages are developed from the references of the previous books knowledge, combined by following codes of Normal 1/88 and latest methods of rehabilitation and protection. The stages are followed with an order from Initial investigation of visual survey, continuing with diagnostic analysis based on the intrinsic causes due to the conditions of site and architectural errors, Extrinsic natural causes due to climatic, temperature, weather along with some anthropic condition caused by human actions. The results from the diagnostics are further classified according to class based on type of damage as structural and nonstructural. Another class based on nature of degradation mechanism as physical, chemical and biological. Final class based on Type of alteration as reversible and irreversible. The classified alterations are represented using the codes of Normal 1/88 which indicates the Hatching in AutoCAD with the exact dimensions of the case study taken. By using the AutoCAD file with exact dimensions and hatchings calculation of individual alterations is possible. By the Detailed analysis and esteemed calculations of alterations type of renovation can be suggested in an order as cleaning followed by repairs and strengthening finally protection measurements can be ensured. As from the suggested renovation and market price of material along with the present labor, technicians daily charge the final cost estimation can be calculated.

AbstractThis paper reconsiders the possibilities for heritage conservation through everyday practices found in temporary uses as relevant and cost-effective tools in a constantly transforming urban environment, contributing to a more sustainable urban development. For this aim, three of the author’s previous case studies of temporary uses in the city of Berlin are reconsidered from the perspective of heritage conservation through everyday practices and citizen participation. Berlin, with its rapidly changing urban environment since 1989, has been an experimental hub for countless temporary uses in a short period of time and therefore provides useful insights into the viability of temporary uses for urban heritage conservation from a variety of perspectives. This paper shows that temporary uses, especially ones that develop into permanent businesses, help to protect buildings from decay, revitalize neglected urban areas, contribute to the realization of the SDGs, and provide affordable spaces for cultural and social activities.

AbstractIn this first chapter of the Book “Regenerative Territories. Dimensions of Circularity for Healthy Metabolisms”, the relation between circularity and space is explored. The main focus is the development over time, and in particular the way how spatial planning and strategies respond to new unpredictable urgencies and opportunities related with territorial metabolisms. In relation to space and time, 5 grand rules are explored as necessary to implement the transition towards Circularity: (1) The Circular Economy paradigm shift requires a socio-ecological perspective and looking beyond boundaries; (2) Circular Economy is based on systems thinking and territorial metabolism; (3) a Circular Economy calls for a renewed approach to the public domain and stakeholder involvement; (4) amplifying the definition of Circular Economy with the inclusion of wastescapes; and (5) Planning the Circular Economy as an open collaborative system. The paradigm shift of contemporary planning towards circularity is aimed to facilitate the capacity of cities to be adaptive and flexible to the speeding up of the biggest changes in the present-day society. Therefore, the relation between the various spatial scales is strictly interlinked to the time scales, as well as to the metabolic processes and Life Cycles of Territories. In this perspective, the “existing city” is a non-negotiable common heritage, the result of a “selective accumulation” of material and immaterial traces produced by the slow and progressive anthropic work in the territory. Contemporary spatial planning looks beyond boundaries. This concerns both the physical boundaries between areas or countries, both the boundaries of the various scale levels of solutions, of the interrelated networks, of the public space and, particularly, of their reciprocity. It induces the scrutinization of the underlying social needs and the finding of instruments that allow the spatial planning and renewed infrastructure to fit the changing social objectives such as sustainability and liveability. The territory of the Circular Economy is the city, as a complex and multidimensional organism. However, the most problematic field for experimenting with “circular planning” is the peri-urban territory consisting of urbanized areas, crossed by differentiated phenomena of settlement expansion beyond the limits of the countryside, which identifies rural and open space, traditionally coinciding with the limits of the city. A circular planning for the regeneration of the peri-urban identifies the waste spaces, the decay of the territory, the obsolescence and end of life of buildings, functions and urban parts now inadequate, namely wasted landscapes (wastescapes). The latter are both the result of metabolic transformations of the territory and generator of prospects and potential for rebalancing the material welfare of the city.

The purpose of the study is to investigate the potential of the CO2-based tracer gas methods for the ventilation performance evaluation in apartment buildings. To test and elaborate the methods, the ventilation air change rate (ACR) and air change efficiency (ACE) measurements were performed. The methods were tested in laboratory conditions and apartments with natural ventilation, room-based ventilation units, exhaust ventilation and mechanical exhaust ventilation with fresh air radiators. Concentration decay method is applied with both artificially and naturally increasing the concentration of tracer gas. The ACR is also calculated using metabolic constant dosing method with the effective volume. As the traditional tracer gas methods give the correct result only in case of perfect mixed ventilation, then the ACE is also measured. To observe the effectiveness of the air change and the level of air mixing multiple CO2 sensors placed in different positions. The tracer gas measurements were carried out in naturally ventilated apartments to study the influence of the inner doors to the ACE. The daily variation of CO2 level in case the long-term CO2 measurements gives us the possibility to calculate the ACR when inhabitants are sleeping or have left the apartment. Using the CO2 as the natural tracer gas and the concentration decay method together with the metabolic constant dosing strategy, we can calculate the CO2 concentrations according to the long-term CO2 measurements without knowing the exact emission of inhabitants. The studied methods are inexpensive and at the same time sufficiently accurate for airflow measurements. Another reason for the study comes from the ventilation retrofit process in Estonia where the single room ventilation units are used. As these wall-mounted ventilation units are sensitive to in- and outside pressure differences the measurement of ventilation airflow in the traditional way can be inaccurate.

Clearance of buildings of nuclear installations in Germany has to comply with general requirements laid down in Section 29 of the German Radiation Protection Ordinance (RPO; Strahlenschutzverordnung), clearance levels as stipulated in Table 1 of Annex III RPO and technical guidance given in the technical standard DIN 25457. Clearance procedures are usually proposed by the licensee and are made part of a decommissioning licence after appropriate review by the authorities. The clearance procedures consist of a radiological characterisation of the various parts of the buildings, a decontamination step if necessary, followed by measurements for checking the success of decontamination, and the actual decision measurements for demonstrating compliance with clearance levels. These three steps rely on various measurement methods, selected depending on the relevant radionuclides to be measured, like sampling with subsequent gamma spectrometry (and if necessary separate evaluation of beta and alpha emitting nuclides), measurements with surface contamination monitory and in situ gamma spectrometry. For a nuclear power plant, the number of samples taken during this procedure can easily reach a few 10,000, while the number of single measurements can reach several 100,000 single surface measurements and several 10,000 measurements with in situ gamma spectrometry. This large number of data together with the correct interpretation according to the valid nuclide vector, the penetration depth of the contamination, the correction for radioactive decay etc have to be managed, which is a error-prone process if carried out manually or with insufficient support by customised software. For this reason, a versatile software tool has been developed by Brenk Systemplanung GmbH that supports the operator in all aspects of clearance of buildings, based on the extensive experience with various clearance procedures in nuclear power plants that Brenk Systemplanung has carried out in the past. Many steps of the data evaluation and report generation during the clearance process outlined above can now be carried out automatically. This includes the time-consuming steps of: • support during the acquisition of the geometry data for a room, • generation of the lists for sampling and measurements, • automatic acquisition of the measurement and sampling results from the instruments, • evaluation of compliance with clearance levels, both for measurements on the entire surface and for statistically distributed measurements or samples, • generation of the documentation on clearance, • storage of all data, generation of nuclide vectors, correction for radioactive decay, connection with photo, CAD drawings etc.

The small village of Pesche in Molise extends along the slopes of Monte San Marco, in a perfect symbiosis between architecture and nature. Pesche’s origins date back already between the 5th and 6th century, when the steep natural slope was chosen as a place for the construction of a safe village, consisting of many small houses side by side and built using local limestone. Its position, guarding the Isernia valley, characterized at the top by the ruins of the castle-enclosure, supports the idea that Pesche may have played a dominant role in the passage along the ancient Pescasseroli-Candela sheep track. The castle-enclosure itself is evidence of the traditional medieval building site, but also of a rural civilization which until the beginning of the 20th century probably continued to live in these places, used as houses, stables and barns. This contribution focuses on the architectural and material characteristics of the buildings in the territory of Pesche, which, despite the current state of decay and neglect, are evidence of the use of local materials and the use of construction techniques that have characterized the traditional Molise building site

The study of the hydraulic factories (mills, forges, trip hammers, etc.) of the Valle Sabbia, conducted by a University of Brescia research group, within the "Resilient Valleys" project (funded by the Cariplo Foundation), led to the definition of a protocol or guidelines with the ambition of identifying shared and adequate codes of practice to guarantee the correct recovery of this heritage. The object of the survey are artefacts located in functional positions for production activities, today often isolated and not very accessible. The architectural structure and construction features make them particularly vulnerable to deterioration, moreso than other types of artefacts. What remains of this building heritage is much closer to the conditions of a ruin which, if recovered or simply maintained, could very effectively convey some of the most characteristic features of local economic history. To conserve and maintain this heritage, operational indications and good practice suggestions are proposed, useful in interventions on buildings and hydraulic artefacts. There is neither a compendium with recipes to follow step by step nor even exemplary models, but rather a critical path method that starts from the direct and physical knowledge of the heritage, to arrive at the timely and most suitable conservation intervention. Method suggestions are proposed, which aim to help the owners, users or managers of these architectures, in choosing, within a scenario of traditional and innovative construction techniques available, the most suitable and correct ones to guarantee respect for the buildings’ and hydraulic works’ characteristics, their constructive, morphological, technological, material peculiarities and, therefore, to monitor and/or solve problems of decay and instability. Ample space is also dedicated to the planned conservation process, in which enhancement will contribute to respecting the material and intellectual integrity of the ruin.

Undesired vibrations in structures, buildings, and machines lead to reduction in the life of the system and greatly affects the safety of the occupying or operating personnel. In addition, economic and time losses could result from needed repairs or reconstruction. Many control techniques, active and passive, have been devised over the years to reduce/eliminate the vibrations in the aforementioned systems. Passive vibration control techniques are favorable over the active ones due to their simplicity, ease of implementation, cost, and power consumption. In dynamic structures, such as large buildings, passive control techniques are favored over their active counterparts. The most common types of passive control devices are tuned mass and impact dampers. The advocates of each of these devices boasts advantages of the others; however, there have been no systematic studies to compare and quantify the effectiveness of each of these types of devices as well as their suitability for specific applications. In this paper, a comparative study between the tuned mass dampers and impact dampers is conducted. A one-story structure is used to show the effectiveness of each of these devices in absorbing the vibrations of the structure. The coupled systems are modeled and simulated under free vibrations. The time responses are acquired using the same geometric parameters, excitation, and initial conditions. The comparisons are based on the settling time and amplitude decay rates of the primary system using each damper type. The numerical results show that both dampers can produce similar dampening effects if the parameters are optimized; however, correlating the dampers parameters is a challenging problem in the field of vibration and control.

Tritium (H13) is a radioactive isotope of hydrogen formed by ternary fission events (rare emissions of three nuclides rather than two during a fission) and neutron absorption (and subsequent decay) of predecessor radionuclides, particularly 6Li and 7Li. Also in fusion, the concept of breeding tritium during the fusion reaction is of significance for the future needs of a large-scale fusion power plant. Tritium is of special interest among the fission products created in next-generation nuclear reactors such as gas cooled reactors and molten salt reactors, because of the large quantities produced when compared with conventional light-water reactors (LWR) and the higher temperatures of operation for these systems enhances permeation. To prevent the tritium contamination of proposed reactor buildings and surrounding sites, this paper examines the root causes and potential solutions for mitigation of permeation of this radionuclide, including materials selection and inert gas sparging. A model is presented that can be used to predict permeation rates of hydrogen through metallic alloys at temperatures from 450–750°C. Results of the diffusion model are presented along with mitigation strategies for tritium permeation.

Building 550 (former World War II fire station) is located on Fort McCoy, Wisconsin, and was recommended eligible for the National Register of Historic Places (NRHP) in 2018 (Smith and Adams 2018). The building is currently vacant. It is an intact example of an 800 Series World War II fire station with character-defining features of its period of significance from 1939 to 1946 on its exterior and interior. All buildings, especially historic ones, require regular planned maintenance and repair. The most notable cause of historic building element failure and/or decay is not the fact that the historic building is old, but rather it is caused by incorrect or inappropriate repair and/or basic neglect of the historic building fabric. This document is a maintenance manual compiled with as-is conditions of construction materials of Building 550. The Secretary of Interior Guidelines on rehabilitation and repair per material are discussed to provide the cultural resources manager at Fort McCoy a guide to maintain this historic building. This report satisfies Section 110 of the National Historic Preservation Act (NHPA) of 1966 as amended and will help the Fort McCoy Cultural Resources Management office to manage this historic building.

The goal of fire service training is to prepare students for the conditions and challenges that they face on the fireground. Among the challenges that firefighters routinely face on the fireground are ventilation-controlled fires. The hazard of these fires has been highlighted by several line-of-duty deaths and injuries in which a failure to understand the fire dynamics produced by these fires has been a contributing factor. The synthetic fuels that commonly fill contemporary homes tend to result in ventilation-controlled conditions. While synthetic fuels are common on the residential fireground, the fuels that firefighters use for fire training are more often representative of natural, wood-based fuels. In order to better understand the fire dynamics of these training fires, a series of experiments was conducted in a concrete live fire training building in an effort to evaluate the fidelity and safety of two training fuels, pallets and OSB, and compare the fire dynamics created by these fuels to those created by a fuel load representative of a living room set with furniture items with a synthetic components. Additionally, the effects of the concrete live fire training building on the fire dynamics were examined. The two training fuel loads were composed of wooden pallets and straw, and pallets, straw, and oriented strand board (OSB). The results indicated that the high leakage area of the concrete live fire training building relative to the fuel load prevented the training fuel packages from becoming ventilation-controlled and prevented the furniture package from entering a state of oxygen-depleted decay. The furniture experiments progressed to flashover once ventilation was provided. Under the conditions tested, the wood based fuels, combined with the construction features of this concrete live fire training building, limited the ability to teach ventilation-controlled fire behavior and the associated firefighting techniques. Additionally, it was shown that the potential for thermal injury to firefighters participating in a training evolution existed well below thresholds where firefighter PPE would be damaged.

The BALIKA project evaluated whether three skills-building approaches to empower girls can effectively delay the age at marriage among girls aged 12–18 in parts of Bangladesh where child marriage rates are at their highest. BALIKA results show that programs that educate girls, build their skills for modern livelihoods and engage their communities can delay child marriage and produce better health, educational and social outcomes for girls.

The BALIKA project evaluated whether three skills-building approaches to empower girls can effectively delay the age at marriage among girls aged 12–18 in parts of Bangladesh where child marriage rates are at their highest. BALIKA results show that programs that educate girls, build their skills for modern livelihoods and engage their communities can delay child marriage and produce better health, educational and social outcomes for girls. This brief summarizes the project's endline results.

In additive construction, ambitious goals to fabricate a concrete building in less than 24 hours are attempted. In the field, this goal relies on a metric of print time to make this conclusion, which excludes rest time and delays. The task to complete a building in 24 hours was put to the test with the first attempt at a fully continuous print of a structurally reinforced additively constructed concrete (ACC) building. A time series analysis was performed during the construction of a 512 ft2 (16’x32’x9.25’) building to explore the effect of delays on the completion time. This analysis included a study of the variation in comprehensive layer print times, expected trends and forecasting for what is expected in future prints of similar types. Furthermore, the study included a determination and comparison of print time, elapsed time, and construction time, as well as a look at the effect of environmental conditions on the delay events. Upon finishing, the analysis concluded that the 3D-printed building was completed in 14-hours of print time, 31.2- hours elapsed time, a total of 5 days of construction time. This emphasizes that reports on newly 3D-printed constructions need to provide a definition of time that includes all possible duration periods to communicate realistic capabilities of this new technology.

Investigations of recent firefighter line of duty deaths caused by rapid fire progression have highlighted a deficiency in firefighters’ understanding of how certain tactics affect the fire dynamics of ventilation-controlled fires. Many fires are in a ventilation-limited, decay state by the time firefighters arrive at the scene, meaning that introducing additional ventilation to the environment has the potential to cause rapid and intense fire growth. To more effectively teach firefighters about the potential effects of ventilation on a compartment fire, ventilation-controlled fires should be gener- ated during training. Safely creating such fires while maintaining compliance with NFPA 1403: Standard on Live-Fire Training Evolutions allows instructors to educate students on this important principle of fire dynamics in the training environment. Structures utilized for live-fire training have evolved from typical concrete burn buildings to now include smaller purpose-built props, like those constructed from steel shipping containers or wood and gypsum board. Such props have been embraced by organizations due to their cost-effectiveness and potential to improve fire behavior training. Obtaining a thorough understanding of the capa- bilities and limitations of such props is critical for instructors to convey accurate messages during training and properly prepare firefighters for scenarios they’ll encounter in the field. Experiments were conducted to quantify the fire environment in L-shaped props with different wall constructions. One prop had an interior wall lining of gypsum board over wood studs and fiberglass insulation. The two other props were constructed from metal shipping containers with corrugated steel walls; one had ceilings and walls comprised solely of the corrugated steel, while the other had ceilings and walls comprised of rolled steel sheeting over mineral wool insulation with the corrugated steel wall as its backing. Three fuel packages were compared between the props: one contained furnishings mainly composed of synthetic materials and foam plastics; another contained wooden pallets and straw; and the third contained wooden pallets, straw, and oriented strand board (OSB). A stochastic approach was used to compare data between replicate tests and quantify the repeatability of the different props and fuel packages, all of which were deemed sufficiently repeatable. Comparisons of data between the three props revealed that thermal conditions between experiments in the two metal props were indistinguishable, suggesting that the additional layer of insulation did not significantly alter the fire environment. Additionally, thermal conditions in the gypsum-lined prop were more severe than those in the metal props. The effects of ventilation changes on fire conditions were also analyzed across various prop and fuel load combinations. Lastly, the response of the thermal environment in each prop during interior suppression was evaluated, and the results implied that the thermal exposure to the firefighter was more severe in the metal props than the gypsum prop for a brief period following the start of suppression.

1.1 Macroeconomic summary Economic recovery has consistently outperformed the technical staff’s expectations following a steep decline in activity in the second quarter of 2020. At the same time, total and core inflation rates have fallen and remain at low levels, suggesting that a significant element of the reactivation of Colombia’s economy has been related to recovery in potential GDP. This would support the technical staff’s diagnosis of weak aggregate demand and ample excess capacity. The most recently available data on 2020 growth suggests a contraction in economic activity of 6.8%, lower than estimates from January’s Monetary Policy Report (-7.2%). High-frequency indicators suggest that economic performance was significantly more dynamic than expected in January, despite mobility restrictions and quarantine measures. This has also come amid declines in total and core inflation, the latter of which was below January projections if controlling for certain relative price changes. This suggests that the unexpected strength of recent growth contains elements of demand, and that excess capacity, while significant, could be lower than previously estimated. Nevertheless, uncertainty over the measurement of excess capacity continues to be unusually high and marked both by variations in the way different economic sectors and spending components have been affected by the pandemic, and by uneven price behavior. The size of excess capacity, and in particular the evolution of the pandemic in forthcoming quarters, constitute substantial risks to the macroeconomic forecast presented in this report. Despite the unexpected strength of the recovery, the technical staff continues to project ample excess capacity that is expected to remain on the forecast horizon, alongside core inflation that will likely remain below the target. Domestic demand remains below 2019 levels amid unusually significant uncertainty over the size of excess capacity in the economy. High national unemployment (14.6% for February 2021) reflects a loose labor market, while observed total and core inflation continue to be below 2%. Inflationary pressures from the exchange rate are expected to continue to be low, with relatively little pass-through on inflation. This would be compatible with a negative output gap. Excess productive capacity and the expectation of core inflation below the 3% target on the forecast horizon provide a basis for an expansive monetary policy posture. The technical staff’s assessment of certain shocks and their expected effects on the economy, as well as the presence of several sources of uncertainty and related assumptions about their potential macroeconomic impacts, remain a feature of this report. The coronavirus pandemic, in particular, continues to affect the public health environment, and the reopening of Colombia’s economy remains incomplete. The technical staff’s assessment is that the COVID-19 shock has affected both aggregate demand and supply, but that the impact on demand has been deeper and more persistent. Given this persistence, the central forecast accounts for a gradual tightening of the output gap in the absence of new waves of contagion, and as vaccination campaigns progress. The central forecast continues to include an expected increase of total and core inflation rates in the second quarter of 2021, alongside the lapse of the temporary price relief measures put in place in 2020. Additional COVID-19 outbreaks (of uncertain duration and intensity) represent a significant risk factor that could affect these projections. Additionally, the forecast continues to include an upward trend in sovereign risk premiums, reflected by higher levels of public debt that in the wake of the pandemic are likely to persist on the forecast horizon, even in the context of a fiscal adjustment. At the same time, the projection accounts for the shortterm effects on private domestic demand from a fiscal adjustment along the lines of the one currently being proposed by the national government. This would be compatible with a gradual recovery of private domestic demand in 2022. The size and characteristics of the fiscal adjustment that is ultimately implemented, as well as the corresponding market response, represent another source of forecast uncertainty. Newly available information offers evidence of the potential for significant changes to the macroeconomic scenario, though without altering the general diagnosis described above. The most recent data on inflation, growth, fiscal policy, and international financial conditions suggests a more dynamic economy than previously expected. However, a third wave of the pandemic has delayed the re-opening of Colombia’s economy and brought with it a deceleration in economic activity. Detailed descriptions of these considerations and subsequent changes to the macroeconomic forecast are presented below. The expected annual decline in GDP (-0.3%) in the first quarter of 2021 appears to have been less pronounced than projected in January (-4.8%). Partial closures in January to address a second wave of COVID-19 appear to have had a less significant negative impact on the economy than previously estimated. This is reflected in figures related to mobility, energy demand, industry and retail sales, foreign trade, commercial transactions from selected banks, and the national statistics agency’s (DANE) economic tracking indicator (ISE). Output is now expected to have declined annually in the first quarter by 0.3%. Private consumption likely continued to recover, registering levels somewhat above those from the previous year, while public consumption likely increased significantly. While a recovery in investment in both housing and in other buildings and structures is expected, overall investment levels in this case likely continued to be low, and gross fixed capital formation is expected to continue to show significant annual declines. Imports likely recovered to again outpace exports, though both are expected to register significant annual declines. Economic activity that outpaced projections, an increase in oil prices and other export products, and an expected increase in public spending this year account for the upward revision to the 2021 growth forecast (from 4.6% with a range between 2% and 6% in January, to 6.0% with a range between 3% and 7% in April). As a result, the output gap is expected to be smaller and to tighten more rapidly than projected in the previous report, though it is still expected to remain in negative territory on the forecast horizon. Wide forecast intervals reflect the fact that the future evolution of the COVID-19 pandemic remains a significant source of uncertainty on these projections. The delay in the recovery of economic activity as a result of the resurgence of COVID-19 in the first quarter appears to have been less significant than projected in the January report. The central forecast scenario expects this improved performance to continue in 2021 alongside increased consumer and business confidence. Low real interest rates and an active credit supply would also support this dynamic, and the overall conditions would be expected to spur a recovery in consumption and investment. Increased growth in public spending and public works based on the national government’s spending plan (Plan Financiero del Gobierno) are other factors to consider. Additionally, an expected recovery in global demand and higher projected prices for oil and coffee would further contribute to improved external revenues and would favor investment, in particular in the oil sector. Given the above, the technical staff’s 2021 growth forecast has been revised upward from 4.6% in January (range from 2% to 6%) to 6.0% in April (range from 3% to 7%). These projections account for the potential for the third wave of COVID-19 to have a larger and more persistent effect on the economy than the previous wave, while also supposing that there will not be any additional significant waves of the pandemic and that mobility restrictions will be relaxed as a result. Economic growth in 2022 is expected to be 3%, with a range between 1% and 5%. This figure would be lower than projected in the January report (3.6% with a range between 2% and 6%), due to a higher base of comparison given the upward revision to expected GDP in 2021. This forecast also takes into account the likely effects on private demand of a fiscal adjustment of the size currently being proposed by the national government, and which would come into effect in 2022. Excess in productive capacity is now expected to be lower than estimated in January but continues to be significant and affected by high levels of uncertainty, as reflected in the wide forecast intervals. The possibility of new waves of the virus (of uncertain intensity and duration) represents a significant downward risk to projected GDP growth, and is signaled by the lower limits of the ranges provided in this report. Inflation (1.51%) and inflation excluding food and regulated items (0.94%) declined in March compared to December, continuing below the 3% target. The decline in inflation in this period was below projections, explained in large part by unanticipated increases in the costs of certain foods (3.92%) and regulated items (1.52%). An increase in international food and shipping prices, increased foreign demand for beef, and specific upward pressures on perishable food supplies appear to explain a lower-than-expected deceleration in the consumer price index (CPI) for foods. An unexpected increase in regulated items prices came amid unanticipated increases in international fuel prices, on some utilities rates, and for regulated education prices. The decline in annual inflation excluding food and regulated items between December and March was in line with projections from January, though this included downward pressure from a significant reduction in telecommunications rates due to the imminent entry of a new operator. When controlling for the effects of this relative price change, inflation excluding food and regulated items exceeds levels forecast in the previous report. Within this indicator of core inflation, the CPI for goods (1.05%) accelerated due to a reversion of the effects of the VAT-free day in November, which was largely accounted for in February, and possibly by the transmission of a recent depreciation of the peso on domestic prices for certain items (electric and household appliances). For their part, services prices decelerated and showed the lowest rate of annual growth (0.89%) among the large consumer baskets in the CPI. Within the services basket, the annual change in rental prices continued to decline, while those services that continue to experience the most significant restrictions on returning to normal operations (tourism, cinemas, nightlife, etc.) continued to register significant price declines. As previously mentioned, telephone rates also fell significantly due to increased competition in the market. Total inflation is expected to continue to be affected by ample excesses in productive capacity for the remainder of 2021 and 2022, though less so than projected in January. As a result, convergence to the inflation target is now expected to be somewhat faster than estimated in the previous report, assuming the absence of significant additional outbreaks of COVID-19. The technical staff’s year-end inflation projections for 2021 and 2022 have increased, suggesting figures around 3% due largely to variation in food and regulated items prices. The projection for inflation excluding food and regulated items also increased, but remains below 3%. Price relief measures on indirect taxes implemented in 2020 are expected to lapse in the second quarter of 2021, generating a one-off effect on prices and temporarily affecting inflation excluding food and regulated items. However, indexation to low levels of past inflation, weak demand, and ample excess productive capacity are expected to keep core inflation below the target, near 2.3% at the end of 2021 (previously 2.1%). The reversion in 2021 of the effects of some price relief measures on utility rates from 2020 should lead to an increase in the CPI for regulated items in the second half of this year. Annual price changes are now expected to be higher than estimated in the January report due to an increased expected path for fuel prices and unanticipated increases in regulated education prices. The projection for the CPI for foods has increased compared to the previous report, taking into account certain factors that were not anticipated in January (a less favorable agricultural cycle, increased pressure from international prices, and transport costs). Given the above, year-end annual inflation for 2021 and 2022 is now expected to be 3% and 2.8%, respectively, which would be above projections from January (2.3% and 2,7%). For its part, expected inflation based on analyst surveys suggests year-end inflation in 2021 and 2022 of 2.8% and 3.1%, respectively. There remains significant uncertainty surrounding the inflation forecasts included in this report due to several factors: 1) the evolution of the pandemic; 2) the difficulty in evaluating the size and persistence of excess productive capacity; 3) the timing and manner in which price relief measures will lapse; and 4) the future behavior of food prices. Projected 2021 growth in foreign demand (4.4% to 5.2%) and the supposed average oil price (USD 53 to USD 61 per Brent benchmark barrel) were both revised upward. An increase in long-term international interest rates has been reflected in a depreciation of the peso and could result in relatively tighter external financial conditions for emerging market economies, including Colombia. Average growth among Colombia’s trade partners was greater than expected in the fourth quarter of 2020. This, together with a sizable fiscal stimulus approved in the United States and the onset of a massive global vaccination campaign, largely explains the projected increase in foreign demand growth in 2021. The resilience of the goods market in the face of global crisis and an expected normalization in international trade are additional factors. These considerations and the expected continuation of a gradual reduction of mobility restrictions abroad suggest that Colombia’s trade partners could grow on average by 5.2% in 2021 and around 3.4% in 2022. The improved prospects for global economic growth have led to an increase in current and expected oil prices. Production interruptions due to a heavy winter, reduced inventories, and increased supply restrictions instituted by producing countries have also contributed to the increase. Meanwhile, market forecasts and recent Federal Reserve pronouncements suggest that the benchmark interest rate in the U.S. will remain stable for the next two years. Nevertheless, a significant increase in public spending in the country has fostered expectations for greater growth and inflation, as well as increased uncertainty over the moment in which a normalization of monetary policy might begin. This has been reflected in an increase in long-term interest rates. In this context, emerging market economies in the region, including Colombia, have registered increases in sovereign risk premiums and long-term domestic interest rates, and a depreciation of local currencies against the dollar. Recent outbreaks of COVID-19 in several of these economies; limits on vaccine supply and the slow pace of immunization campaigns in some countries; a significant increase in public debt; and tensions between the United States and China, among other factors, all add to a high level of uncertainty surrounding interest rate spreads, external financing conditions, and the future performance of risk premiums. The impact that this environment could have on the exchange rate and on domestic financing conditions represent risks to the macroeconomic and monetary policy forecasts. Domestic financial conditions continue to favor recovery in economic activity. The transmission of reductions to the policy interest rate on credit rates has been significant. The banking portfolio continues to recover amid circumstances that have affected both the supply and demand for loans, and in which some credit risks have materialized. Preferential and ordinary commercial interest rates have fallen to a similar degree as the benchmark interest rate. As is generally the case, this transmission has come at a slower pace for consumer credit rates, and has been further delayed in the case of mortgage rates. Commercial credit levels stabilized above pre-pandemic levels in March, following an increase resulting from significant liquidity requirements for businesses in the second quarter of 2020. The consumer credit portfolio continued to recover and has now surpassed February 2020 levels, though overall growth in the portfolio remains low. At the same time, portfolio projections and default indicators have increased, and credit establishment earnings have come down. Despite this, credit disbursements continue to recover and solvency indicators remain well above regulatory minimums. 1.2 Monetary policy decision In its meetings in March and April the BDBR left the benchmark interest rate unchanged at 1.75%.