Robust and reliable deep renovation by advanced prefabricated façade elements. Air-tightness performance and assessment of a demo case

Deep renovation of the existing building mass is an important task to reach the target of energy efficient buildings and neighbourhood. However, the current renovation rate is only 1% of the European building stock each year, and barrier for increased rate must be addressed. Attaching prefabricated elements with integrated technologies such as photovoltaic panels or ventilation equipment to the façades and roofs can improve energy performance and indoor climate as well as provide local renewable energy supply. The construction period can be short, with limited disturbance to building usage. The project 4RinEU has developed and demonstrated solutions suitable for several climates. Building airtightness of the renovated buildings is an important design goal of the refurbishment, and is determined by blower-door tests before and after renovation. This paper presents air-tightness results from a demo case study in Norway. In the demo case the airtightness as determined by blower-door tests quite unexpectedly deteriorated, while the design goal for the projects was a major improvement. Probable causes for the discrepancy are discussed, and include leakage from the ground, in element joints and in unplanned openings.publishedVersio

Omsorgsbygg med plussenergi-ambisjoner

I Bærum kommune er det oppført et demobygg som er en del av EU-prosjektet Cultural-E. SINTEF er forskningspartner, og bidrar med å definere løsninger for plussenergibygninger under norske forhold.publishedVersio

Demand-controlled ventilation in schools: Influence of base ventilation rates on subjective symptoms, perceived indoor environment and young adults' learning performance

The ventilation airflow rates in a demand-controlled ventilation strategy typically vary between a base (Vmin) and a maximum ventilation rate (Vmax). Classrooms have relatively short but intense hours of occupancy and a low Vmin can result in high energy savings. Our study aims to examine how different Vmin (1.1 versus 2.0 l/s per m²) affect subjective symptoms, perceived indoor environment quality (IEQ), and performance for young adults. Symptom intensity and perceived IEQ were recorded on a visual scale, and performance was examined by identifying three different letters in a nonsense text. Tests were done immediately after entering the classroom. We found no significant effects of increasing Vmin from 1.1 to 2.0 l/s per m² on learning performance, symptoms, or perceived IEQ.publishedVersio

Spatiotemporal humidity variation in student housing

Modern, urban apartments are space-efficient, have bathrooms with no windows, and require energy-efficient ventilation with heat recovery. The requirements for exhaust ventilation rates for the kitchen and bathrooms are independent of dwelling size. In some countries, it is required that the extract air can be increased on demand. There is a need for more knowledge on the effects of these requirements on the resulting moisture level in apartments, and whether these recommendations should be modified. Measurements were done in eight student apartments. Temperature and humidity were measured with 1-minute time resolution at 5 locations in each of the apartments. Median moisture excess was 0.9-1.4 g/m³, indicating a small risk of interstitial condensation. 90th percentiles of relative humidity were 30-35 %, indicating an elevated risk of eye and airway symptoms due to low humidity. The moisture excess was lower in apartments with heat-recovery ventilation than mechanical extract ventilation. The median moisture excess was higher in the living rooms than in bathrooms, indicating that moisture from showering and personal hygiene had little impact on the overall indoor moisture conditions in the dwellings. The average number of showers per day per apartment varied between 0.6 and 3.1. High peak moisture excess values up to 20 g/m³ were recorded in bathrooms, but for brief periods only. Consistently higher moisture peaks in extract vents than in bathroom air demonstrated that ventilation extract above the shower is effective in removing moist air from showering. Calculated moisture load in the extract air from a single shower was estimated to be 0.86 kg. Outdoor temperatures were negatively correlated with moisture excess, as predicted by EN -ISO 13788.publishedVersio

Cooking habits and usage of kitchen hoods in Norwegian homes

Sustainable urban development results in more space and energy-efficient apartments. Open plan solutions are becoming more common, and the market is exploring new configurations and ventilation solutions for the kitchen in direction of the design and minimize space for ductwork. Cooking is an important aspect of human life and is considered one of the major sources of particle emissions. The cooking method, the type of cuisine, and the type of kitchen hood are some of the factors that will influence this. In Norway, the minimum requirement for general kitchen exhaust is 36 m3/h, with a minimum additional forced ventilation by the kitchen hood of 108 m3/h. However, these requirements might not be sufficient to mitigate the exposure from cooking. Electricity is the main heating source, traditionally with hot plate, today mainly induction or ceramic cooktop. In this work, we aim to investigate representative Norwegian cooking habits, typical meals and set up a procedure for cooking in the laboratory to perform intensive exposure studies. A survey has been performed to identify the type and usage of kitchen hoods in different living situations as well as typical Norwegian meals. A total of 336 people responded to the survey, of which 111 provided answers to a few additional questions. More than 60% of the respondents belonged in the age groups 30 – 60 years old and 92% owned their dwelling. Wall-mounted kitchen hoods were found in the majority of the homes, and almost 4% had downdraft. Only 12% of the homes had recirculating hoods. 76% of the respondents used the kitchen hood during cooking. The Norwegians mainly cook or fry their food, while deep-frying is not common. For the question related to what meal is most often cooked, the categories of food that were most mentioned were pasta dishes, taco, meat, fish, boiled potatoes, and chicken. Based on this we developed the cooking procedure for three different test meals suitable for exposure studies.publishedVersio

Cooking emissions from typical Norwegian meals: basis for advanced exposure studies

Sustainable urban dwellings are built space-efficient, and open-plan kitchens have increasingly become the norm. A study of newer building projects has shown that the kitchen space is in the inner area of the apartment with limited options for forced window airing, leaving the job of removing cooking emissions to the kitchen hood or general ventilation. One of the aims of our study is to measure exposure from actual cooking in modern apartments, as preparations for further advanced studies. To achieve this, particle number concentrations (>0.3 μm) are measured for three typical Norwegian meals with different ventilation rates at three locations in the kitchen lab. The kitchen setup is comparable to the EN 61591:2019 standard with an area of approximately 30 m2 and a height of 2.7 m. The measurements show that the meals and cooking procedures developed are reasonably repeatable. Most of the particles are in the range 0.3-2.5 μm. The meal producing the lowest numbers of particles is the vegetarian pasta Bolognese, while taco and fried salmon which required both higher cooking temperature and contained more fat resulted in a much higher number of particles. The peak for particle number concentration was more than 40% lower for the vegetarian meal. Turning on the kitchen hood at medium setting (286 m3/h) drastically reduced the particle number concentrations, however, the Norwegian requirement of 108 m3/h (low) resulted in a 58% reduction for the taco meal.publishedVersio

Mostly dry: current ventilation practice efficiently limits moisture excess in mechanically ventilated apartments

The current Norwegian building code (TEK 17) requires the new residential buildings to have balanced ventilation with heat recovery, in addition to the strict regulations regarding thermal performance and airtightness of the fabric. During the cold winters in the South-East part of the country, the moisture content in the air outdoors is very low and results in a dry climate indoors as well. This study investigates in-situ the moisture excess indoors (Δv) in a series of urban residential apartments that have been built according to TEK 17. In particular, air temperature and relative humidity have been measured in six locations/rooms in each of the monitored apartments. Variations in moisture production as well as in ventilation rates have resulted in different moisture excess levels. The findings reveal that the current practice limits moisture excess and have led to an overall reduction of Δv compared to results found in similar studies performed two decades ago. 90th percentiles of Δv have been calculated as below 2 g/m3 in all types of rooms, while in bathrooms it has been 2.6 g/m3. The relative humidity (RH) has been respectively below 30%, with bathrooms being the only exception with RH just over this level. The results from a survey among the occupants showed that most of them complain about fatigue, difficulty in concentrating and a head that feels heavy. In addition, dust and too high air temperature have been identified as the main problems of the indoor environment.publishedVersio

Montana Kaimin, November 7, 1974

Student newspaper of the University of Montana, Missoula.https://scholarworks.umt.edu/studentnewspaper/7368/thumbnail.jp

Reuse of building materials. Guide to the documentation of performance

Preface. The construction industry generates a good deal of waste, and both rehabilitation and new construction require large quantities of building materials. At present, building materials in use are mostly new and also to a large extent manufactured from virgin raw materials. Reuse of building materials can provide environmental benefits that are essential for the sustainable management of resources.However, reuse of a building material presupposes that it is suitable for reuse, in other words that it does not impair the quality of the finished building, compared with using new materials. This guide provides advice about how to assess building materials for reuse. The guide is part of the research project, REBUS (REuse of Building materials – a USer perspective). The objective of the research project is to develop new knowledge to enable the more effective reuse of building materials.publishedVersio