Portail HAL CSTB
Not a member yet
2178 research outputs found
Sort by
Estimation du bruit rayonné par une chute d'eau gravitaire
No full textAcoustique du bâtiment; GABE - Acoustique du Bâtiment et de l'EnvironnementNational audienceLes chutes d’eau gravitaires sont un équipement présent dans les bâtiments d’habitation, les établissements de santé, les établissements d’enseignement, les hôtels ainsi que les bureaux. En ce qui concerne les bâtiments d’habitation, ils font l’objet de non-conformités régulières vis-à-vis de la réglementation acoustique. Depuis juillet 2023, leurs performances acoustiques et structurales peuvent être mesurées selon la norme NF EN 14366-1. Cette norme profondément mise à jour sur le volet du bruit structural décrit le mode opératoire pour mesurer la puissance acoustique et la puissance structurelle. A partir de ces données, il est possible de calculer un niveau de bruit d’équipement pour deux types de bâtiment, à structure lourde avec une paroi support de faible mobilité et les structures légères. Le niveau de bruit aérien est également calculé pour une conduite nue ou une conduite encoffrée dans une gaine technique. L’objectif du présent travail est donc de fournir une estimation du bruit rayonné par un conduit d’évacuation d’eau gravitaire pour deux types de structures de bâtiment lors d’une installation en configuration verticale et/ou horizontale. Ce travail est organisé en deux parties, une première concernant les mesures en laboratoire des grandeurs nécessaires et une seconde à propos de l’estimation par calcul du niveau de bruit rayonné par la chute d’eau
: Développement d’une méthode innovante d’identification des nano- et microplastiques présents dans les environnements intérieurs
No full textInternational audienc
Efficiency and sustainability for removing organic pollutants in aqueous solution: An innovative composite material
No full textInternational audienceComposite materials are attracting considerable interest in water treatment due to their specific properties. Given these properties and the need to remove dyes from water, this work aims to develop an innovative composite material based on local clay (abundant and inexpensive), TiO2 and CuO for wastewater treatment application. Although much work has been devoted to the design of clay-based composites, to our knowledge, no study has explored the use of Boula-Ibib clay decorated with TiO2 and CuO to adsorb tartrazine (TTRZ) in aqueous solution. The CuO–TiO2–clay composite was synthesized by incorporating TiO2 and CuO on the clay surface using the sol–gel method. The crystalline properties, morphology and specific surface area of the composite were examined by X-ray diffraction, X-ray fluorescence, scanning electron microscopy and the Brunauer–Emmett–Teller method respectively. As results, the specific surface area of 85.23 m2·g−1 was obtained for the CuO–TiO2–clay which is higher than that of the raw clay (53.84 m2·g−1). The results of adsorption studies showed a TTRZ uptake capacity of 16.08 mg·g−1 after 30 min, with a concentration of 50 mg·L−1, at pH 6.4 with the optimal composite mass of 0.01 g. Kinetic and isothermal studies showed that adsorption obeyed the pseudo-second-order model and the Radke–Prausnitz isotherm. Thermodynamic studies revealed that the adsorption of TTRZ by the composite is an exothermic, non-spontaneous process that leads to a reduction of disorder in the system. It was established that CuO–TiO2–clay could be effectively reused over four cycles without damage of its structure which represent an economic advantage
Climate change metrics: bridging IPCC AR6 updates and dynamic life cycle assessments
No full textInternational audienceClimate change metrics result from analytical simplification of complex and diverse climate models that are generally not deeply investigated by Life Cycle Assessment communities. We investigated the Sixth Assessment Report of the Intergovernmental Panel on Climate Change to properly gather updated metric equations, climate parameters and associated uncertainties. Metrics are mainly designed with a single gas pulse emission at t0 whereas multi-gas and multi-time pulse emissions are mostly encountered in LCA modelling. Therefore, common static and relative metrics might not suit dynamic climate change assessments (dCCA) that differentiate pulse timing and gas contributions over time. This study focuses on absolute and dynamic metrics – cumulative radiative forcing (AGWP or ΔF) and global temperature change (AGTP or ΔT) – applied to well-mixed greenhouse gases. Cumulative radiative forcing assessment at 20, 100, 500 years appears sufficient. Global temperature change metrics have some advantages that offset their higher uncertainties. (1) Degree Celsius unit better suits peak warming targets. (2) Positive and negative peaks, as well as long-term temperature change, partly alleviate the time horizon decision issue while assessing product systems. (3) Graphical representations are comparable to simultaneously depict short- and long-lived climate forcers. In future assessment reports, IPCC is invited to recall climate equations and updated parameters values in a pedagogical way and to adopt peak and long-term temperature change metrics. dCCA recommendations are to plot ΔF and ΔT temporal profiles of product systems up to 600 years and use suggested metrics. This should enable going towards climate neutrality with more clarity, transparency and understanding
Mitigating Urban Heat Islands with Nature-Based Solutions: The PENATE Project in Action
No full textInternational audienceThe PENATE project seeks to assess the performance and effectiveness of Nature-Based Solutions (NbS) as a critical tool for adapting urban environments to climate change, particularly with regard to microclimate regulation and urban heat island mitigation. Through this project, we aim to develop advanced, multi-scale, multi-criteria, and context-specific evaluation frameworks that will enable local authorities to assess and optimize the deployment of NbS. In addition to microclimate mitigation, these tools will provide actionable insights into the effectiveness of NbS in addressing stormwater management and enhancing the overall quality of life while ensuring ecological continuity.The project is supported by a multidisciplinary consortium that brings together experts in microclimatology, hydrology, ecology, public policy, and law, alongside research organizations and operational entities. PENATE is built around several sites where NbS interventions are actively being monitored, offering valuable real-time data on their impact and performance. This data will be pivotal in advancing our understanding of how NbS can alleviate urban heat islands and contribute to sustainable, climate-resilient cities.Key anticipated outcomes of the project include:- Quantitative insights into NbS’ role in microclimate regulation, especially in mitigating heat islands. How different vegetation types and configurations influence thermal and hydrological processes will be explored, using a functional traits-based approach to connect plant characteristics with performance.- Digital simulation tools that will model and predict the multifunctionality of NbS, offering local authorities the ability to assess their impact across different scales—ranging from local neighborhoods to larger urban regions.- The development of decision-support tools that can directly inform urban planning processes, including regulatory and strategic frameworks like local urban development plans (PLUi), climate air energy plans (PCAET), and objectives such as Zero Net Artificialization (ZAN). These tools will help local authorities implement NbS with a focus on heat justice and urban sustainability, facilitating the integration of nature-based interventions into mainstream urban plannin
Determination of chlordecone in indoor dust by GC/MS/MS and associated human exposure in the French West Indies
No full textInternational audienceChlordecone (CLD) is an organochlorine pesticide with various toxicities, widely used from 1972 to 1993 in the French West Indies lands (FWI, Guadeloupe and Martinique). It can remain in environment leading to indoor contamination by pollutants coming from outside. Therefore, investigating indoor pollutants is necessary due to the potential indoor dust ingestion though hand-to-mouth contact, in particular for children. No chemical analytical method measures CLD in indoor dust and we propose to investigate its presence in this specific compartment, in Martinique. CLD was analyzed from dust samples taken from homes and schools (n = 47). We extracted CLD from dust with pressure liquid extraction (PLE) using a suitable mixture solvent of hexane and ethyl acetate (85:15). This was followed with gas chromatography coupled to tandem spectrometry (GC/MS/MS) analysis. A sampled mass of 25 mg was optimal for analysis. Concentrations of CLD in indoor dust varied from < 16-247 ng/g. Exposure to CLD through indoor dust ingestion was also assessed and does not exceed 1.5 % and 0.1 %, of the acceptable daily intake, in children and adults, respectively. However, this exploratory study was conducted on a very limited number of dust samples limiting the generalization to the whole French West Indies population
Multiphase lock-in spectrometer assembly applied to a modulated source of multi-wavelength optical radiation, and associated methods and uses
No full textThis relates to a multi-phase lock-in spectrometer assembly applied to a modulated source of multi-wavelength optical radiation, wherein the beam coming from the source is divided into two identical quadrature-modulated beams, the two beams being acquired by at least one spectrometer in order to calculate the amplitude spectrum and the phase spectrum of the modulated source of multi-wavelength optical radiation. Also disclosed are associated methods and uses
Campagne nationale logements 2 : Description du budget espace-temps-activités des ménages
No full textAnalyse du Cycle de Vie pour la conception des structures de bâtiments : des matériaux à l’ossature
No full textThe construction sector faces multiple environmental challenges: climate change, intensive resource use, damage to ecosystems, and human health. In this context, this thesis aims to quantify the environmental impacts of building structures and identify ways to reduce these impacts. To achieve this, the thesis proposes integrating Life Cycle Assessment (LCA) to structural design. This approach is developed on several scales, from materials to structures, within the metropolitan French context.First, the work is conducted at the material scale. A literature review is carried out, serving as a foundation for the rest of the manuscript. The goal is to evaluate the environmental impacts of the main structural materials: concrete, steel, wood, and stone. Sensitivity analyses on their production methods are also conducted to identify the origin of these impacts and how to reduce them.The approach is then developed at the scale of structural elements such as beams, columns, and floors. These are the basic building blocks of structural vocabulary, allowing the formation of construction systems. Each element can be found in various geometric configurations (span, height, shape) and loading conditions. This influences the quantity used and thus the associated environmental impacts. This part also introduces alternative stone floor construction systems, which reduce GHG emissions by up to 60% compared to usual systems.The study then focuses on typical building structures composed of the previously described structural elements and materials. This scale accounts for the influence of the building's overall geometry and the interactions between different structural elements. The results show that impacts per square meter decrease as the number of structure levels increases (for the buildings studied, less than 10 levels). There is also a correlation between the increase in floor span and the increase in impacts. Wooden structural systems emit the least GHGs but present significant challenges regarding biodiversity due to land use for forestry. Additionally, the influence of structural choices on the building's energy performance is evaluated to evaluate potential impact transfer.Finally, an assessment of the future impacts of structures is conducted in a European decarbonization context. The arrival of environmental regulations pushes industries to find ways to reduce their GHG emissions and produce decarbonization roadmaps. Based on these assumptions and prospective scenarios, the future environmental impacts of structures are estimated. This allows questioning the decarbonization strategies of materials for structures and highlighting the consequences on other environmental impacts.In conclusion, this work presents the environmental impacts of building structures based on various parameters, including materials and geometry. The multi-criteria LCA approach captures the specific issues of each material and shows the influence of design decisions on human health, biodiversity, and resources. Levers for decarbonizing structures are also examined, notably stone floors. The resulting pollution transfers are identified. The identified solutions do not meet the 2050 objectives of the National Low Carbon Strategy questionning construction volumes. This thesis also highlights the need to improve knowledge on certain impact categories for the construction sector.Le secteur de la construction fait face à des enjeux environnementaux multiples : changement climatique, usage intensif des ressources, dommages sur les écosystèmes et santé humaine. Dans ce contexte, cette thèse a pour objectifs de quantifier les impacts environnementaux des structures de bâtiment et d’identifier des leviers de réduction de ces impacts. Pour cela, la thèse propose d'intégrer l’Analyse du Cycle de Vie (ACV) à la conception des structures. Cette approche est développée sur plusieurs échelles, du matériau à la structure, dans le contexte français métropolitain. Tout d'abord, les travaux sont menés à l'échelle du matériau. Une synthèse de la littérature est réalisée, servant de fondation pour la suite du manuscrit. Le but est d'évaluer les impacts environnementaux des principaux matériaux de structure que sont le béton, l’acier, le bois et la pierre. Des analyses de sensibilité sur leurs moyens de production sont aussi conduites pour identifier l’origine de ces impacts, et les moyens de les réduire. L'approche est ensuite développée à l'échelle des éléments de structures tels que les poutres, poteaux et planchers. Ce sont les briques élémentaires constituant le vocabulaire structurel et permettant de former des systèmes constructifs. Chaque élément peut se retrouver dans une variété de configuration géométrique (portée, hauteur, forme) et de chargement. Ceci influence les quantités de matériaux mises en œuvre et donc les impacts environnementaux associés. Cette partie introduit également des systèmes constructifs alternatifs de plancher en pierre. Ces systèmes réduisent jusqu’à 60% les émissions de gaz à effet de serre (GES) par rapport aux systèmes usuels. L'étude porte ensuite sur des structures de bâtiment classiques composées des éléments structurels et des matériaux précédemment décrits. Cette échelle rend compte de l'influence de la géométrie globale du bâtiment ainsi que des interactions entre les différents éléments structurels. Les résultats montrent notamment que les impacts par m² diminuent quand le nombre de niveaux de la structure augmente (pour les bâtiments étudiés, de moins de 10 niveaux). On observe aussi une corrélation entre l’augmentation de la portée des planchers et celle des impacts. Les typologies structurelles en bois sont les moins émettrices en gaz à effet de serre mais présentent des enjeux importants vis-à-vis de la biodiversité du fait de l’usage des sols pour la sylviculture. De plus, l'influence des choix structurels sur l’énergétique du bâtiment est évaluée pour vérifier qu’il n’y pas de transfert d’impact. Enfin, une évaluation des impacts futurs des structures est réalisée dans un contexte européen de décarbonation. L'arrivée des réglementations environnementales pousse en effet les industriels à trouver des moyens pour réduire leurs émissions de GES et à produire des feuilles de route de décarbonation. En repartant de ces hypothèses et de scénarios prospectifs, les impacts environnementaux futurs des structures sont estimés. Cela permet d’interroger les stratégies de décarbonation de matériaux pour les structures et d'éclairer les conséquences sur d'autres impacts environnementaux. En conclusion, ce travail présente les impacts environnementaux des structures de bâtiment en fonction de différents paramètres, notamment les matériaux et la géométrie. L'approche multicritères de l'ACV permet de saisir les enjeux propres à chaque matériau et de voir l’influence des décisions de conception sur les dommages à la santé humaine, à la biodiversité et aux ressources. Des leviers pour décarboner les structures sont également examinés et les transferts d’impact engendrés évalués. Les solutions identifiées ne permettent pas de respecter les objectifs 2050 de la Stratégie Nationale Bas Carbone questionnant les volumes construits. Cette thèse met également en évidence la nécessité de perfectionner les connaissances sur certaines catégories d’impacts pour le secteur de la construction
Gas Emissions during Smoldering in Biobased Insulation: Experimental Study of the Role of Wood Fiber Board Density
No full textInternational audienceBio-based insulating materials are increasingly used in construction due to their environmental benefits. However, these materials are particularly susceptible to smoldering fires, a phenomenon of slow, flameless and self-sustaining combustion, that is very difficult to detect. This study includes two experimental approaches to analyze smoldering fires in wood fiber boards with low (50 kg/m³) and high (140 kg/m³) densities. The tests were conducted using a cone calorimeter (ISO 5660-1) and a smoldering fire test device (EN 16733). The cone calorimeter uses small-sized samples with continuous thermal exposure, whereas the smoldering fire test bench involves discontinuous thermal exposure and larger sample dimensions. The objective is to better understand the differences in thermal behavior, gas emissions, and material degradation characteristics, while considering key factors influencing the propagation of smoldering fires, such as density or additives. Despite several studies addressing these key factors, a full understanding of the underlying mechanisms has yet to be achieved. The results show that the low-density wood fiber board degrades more rapidly, reaching high combustion temperatures in a shorter period. Incontrast, the high-density fiber board has a greater thermal inertia and prolonged combustion. Regarding gas emissions, concentrations of CO, CO₂, and methane vary depending on fiber density, with low-density samples producing higher yield of CO. These findings aim to enhance the understanding of the smoldering behavior of bio-based materials and to emphasize the importance of chemical aspects such as toxic gasemissions, The study contributes to inform future improvements in fire safety practices and may serve as a basis for revisiting or complementing existing fire safety guidelines. The results contribute to a better understanding of the smoldering combustion behavior of bio-based materials, particularly in relation to material density and its influence on fire dynamics. This knowledge is essential for informing practical fire safety strategies, such as early detection systems and material selection in low-ventilation environments and could help to refine fire performance assessment methods within the built environment