Saint-Gobain (Norway)

This article presents parts of a wide survey on acoustic comfort in Swedish family buildings, specificallywith focus on timber light-weight buildings. The scope of the whole research is to investigate acousticcomfort dimensions after collecting and combining data from standardized acoustic measurements andsubjective responses from a questionnaire survey. Certain noise sources were reported as dominantwithin living environments, impact noise from neighbors being the most important. Installation noisefrom inside the building and outdoor low-frequency noise disturb also a lot. However, the overall levelof acoustic comfort in contemporary wooden buildings seems satisfactory.

In order to reduce energy use and improve indoor environmental quality (IEQ), new and retrofitted dwellings are increasingly equipped with complex heating and mechanical ventilation solutions, which occupants have to learn to use and live with. This work investigates the different ways in which occupants integrate these technologies into daily domestic practices, the associated difficulties and their potential consequences on comfort and building performance. Semi-structured interviews were carried out with occupants of 37 new and retrofitted low-energy dwellings around Copenhagen (Denmark), focusing on occupants’ domestication of underfloor heating and mechanical ventilation. While most respondents were largely satisfied with the IEQ in their homes, the interviews highlighted a disconnection between expected and real uses and perceptions of these technologies. The design assumptions were sometimes unable to reflect occupants’ expectations, including regarding personal control needs. Moreover, installation and operational failures were frequent and difficult for users to diagnose and correct, as they lacked relatable technical guidance. Consequently, occupants often resorted to alternative ways of taking control, which could prove detrimental for energy use and IEQ. The findings highlight the need for incorporating interdisciplinary insights on in-use performance in the design and installation of building systems, making them more robust, reliable and transparent.

Author Summary: This work illustrates variographic analysis applied to industrial production processes to identify and reduce adverse production deviations (over-specification, loss) and evaluate profitability. A first example concerns production of light-weight expanded clay aggregates (Exclay), produced in cement-like rotary kilns. Clay raw material is heated to 1150 °C to be expanded. An adverse periodicity was observed in a specific plant cooler manifested as fluctuations in the material volume (height level) causing a periodic variance in the production output from the kiln. This problem must be resolved by instigating a more stable cooler, which could in fact be engineered by a very small investment of about 5,000 Euro. A variogram characterization was carried out to evaluate the amplitude of the periodicity, and the quantities involved (losses), which information was used to calculate the investment pay-back time. From the variogram it was observed that the reduced kiln output volume was at least 0.7%. During one year with improved cooler level control, this translates into savings of about 100,000 Euro, i.e. a pay-back time will be less than one month. A second example is from a LRM-project (Loss and Reduction Model) at a plant producing bagged pre-mixed mortars, in which the variance of the weight of the produced bags was found to be consistently too large. A pilot variographic analysis was applied with an aim to identify the root causes of this problem (three filling stations at the same line were investigated, all with identical filling systems and scales): Two stations were found to have a total material loss of 1.2%, while the third was running perfectly well (low V(0) and low sill), but with a too high set point. The technical resolution shows that it is possible to reduce material loss with existing equipment by improved monitoring/recording routines but no need to acquire new expensive belt scales a.o. For two of the stations V(0) (MPE) was in fact at a level almost identical to the sill making it structurally impossible to keep bag weight within specifications. Recurrent monitoring of V(0) and moving average smoothing should be evaluated at the very many similar production lines in the multinational corporation involved to gain improved process control to reduce overfilling. While relatively small on the basis of an individual filling line, the potential accumulated corporate savings take on a quite different economic significance. Variographic analysis is a powerful tool for industrial technicians and process engineers to improve processes —and in the present cases for industrial managers as well for evaluating ultimate investment profitability in industrial processes.