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Methods and Metrics for Moisture Risk Assessment- Solid Wall Insulation (MRA-SWI)

潮湿风险评估的方法和指标 - 实心墙绝缘 (MRA-SWI)

基本信息

批准号：
EP/R008329/1
负责人：
David Allinson
金额：
$ 12.6万
依托单位：
Loughborough University
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2018
资助国家：
英国
起止时间：
2018 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FR008329%2F1
关键词：
Methods Metrics Moisture Risk Assessment

项目摘要

If the significant numbers of dwellings with solid masonry walls (SMWs) are to be insulated, there will have to be a paradigm shift in the way that moisture risk is assessed. Methods must be developed to clearly demonstrate that insulation solutions are effective, robust and resilient to moisture even when considering the vagaries of our future climate and the way that people choose to live in their homes. This research will result in new methods and metrics, backed by rigorous scientific evidence, that enable moisture risk assessment of SMWs to be carried out routinely, new insulation materials to be developed and more homes to be insulated.Insulating the UKs existing housing stock will be an essential step in achieving greenhouse gas reduction targets and alleviating fuel poverty. The highest levels of heat loss occur in the c30% (8 million) homes that have SMWs. Insulating these walls offers significant potential for fuel savings but may cause moisture problems. Water accumulates within SMWs when it is raining outside or humid inside and diminishes with drier conditions. This water can pass from one face of the wall to the other as there is no cavity to act as a capillary break. Applying insulation to either the inside or outside face of the wall changes the temperature of the masonry, the rate of wetting and drying at each face and the locations where water vapour might condense and accumulate. This moisture can lead to mould growth, interstitial condensation and freeze thaw damage. These problems can cause severe damage, are expensive to repair and can affect the health of occupants.Current guidance in the UK Building Regulations (approved document C) and related standards is not adequate for assessing moisture risk when insulating SMWs. The simplified steady-state vapour diffusion model is not appropriate because dynamic liquid moisture conduction is the dominant moisture transport mechanism when SMWs are exposed to rainfall. There is a distinct lack of guidance on how to use more advanced transient heat and moisture simulation software, what inputs should be used for the boundary conditions and how the results translate into moisture risk. Straightforward design principles, based on many years of practical experience and research, have led to contradictory advice e.g. there is no clear consensus on how permeable the insulation material should be to water vapour. Thus only a small handful of hygrothermal experts might ever attempt a quantitative risk assessment for insulating SMWs and fewer SMWs are being insulated as a result.This research project will address these problems. Firstly, a framework will be developed for using advanced heat and moisture simulation software to carry out moisture risk assessment. This will include guidance on the boundary conditions to be used at the inside of the wall, and outside especially for wind driven rain exposure. It will also identify appropriate criteria to minimise risk from moisture accumulation within the wall, mould growth at the indoor surface and freeze/thaw at the outside surface. A number of insulation materials will be compared to understand which can best reduce the risk of moisture damage when insulating SMWs. Secondly, probabilistic modelling methods will be used to understand how robust different insulation solutions are to moisture damage given that there is considerable uncertainty in boundary conditions and material properties. Thirdly, new approaches to moisture risk assessment will be explored. A 'moisture safety factor' might describe how resilient an insulated SMW is to extreme events such as flooding. It may be possible to develop a completely new laboratory test for assessing insulation solutions. The underlying strength of this research comes from the collection high quality primary data, in the new state-of-the-art Hygrothermal Test Facility, for validating the results from the models.

如果大量的住宅与固体砌体墙（SMW）是绝缘的，将有一个范式转变的方式，水分风险的评估。必须开发方法来清楚地证明绝缘解决方案是有效的，坚固的和耐潮湿的，即使考虑到我们未来气候的变幻莫测和人们选择居住在家中的方式。这项研究将产生新的方法和指标，有严格的科学证据支持，使SMW的水分风险评估能够定期进行，新的绝缘材料将被开发，更多的房屋将被绝缘。绝缘英国现有的住房存量将是实现温室气体减排目标和缓解燃料贫困的重要一步。最高水平的热损失发生在c30%（800万）拥有SMW的家庭中。隔热这些墙壁提供了节省燃料的巨大潜力，但可能会导致潮湿的问题。当室外下雨或室内潮湿时，水会积聚在SMWs内，并随着干燥情况而减少。由于没有空腔作为毛细血管破裂，这些水可以从壁的一面流到另一面。在墙的内表面或外表面施加隔热材料会改变砌体的温度、每一面的湿润和干燥速率以及水蒸气可能冷凝和积聚的位置。这种水分会导致霉菌生长、间隙冷凝和冻融破坏。这些问题可能会造成严重损害，维修费用昂贵，并可能影响居住者的健康。英国建筑法规（批准文件C）和相关标准中的现行指南不足以评估SMW绝缘时的潮湿风险。简化的稳态水汽扩散模型是不合适的，因为当SMWs暴露于降雨时，动态液体水分传导是主要的水分传输机制。在如何使用更先进的瞬态热和水分模拟软件、边界条件应使用哪些输入以及结果如何转化为水分风险方面，明显缺乏指导。基于多年实践经验和研究的简单设计原则导致了相互矛盾的建议，例如，对于隔热材料对水蒸气的渗透性没有明确的共识。因此，只有少数湿热专家可能会尝试对SMW进行绝缘的定量风险评估，结果是更少的SMW被绝缘。本研究项目将解决这些问题。首先，将开发一个框架，使用先进的热湿模拟软件进行水分风险评估。这将包括在墙内和墙外使用的边界条件的指导，特别是风驱动的雨暴露。它还将确定适当的标准，以最大限度地减少墙壁内水分积聚、室内表面霉菌生长和外表面冻融的风险。将对多种绝缘材料进行比较，以了解哪种绝缘材料在SMW绝缘时可以最好地降低湿气损坏的风险。其次，概率建模方法将被用来了解不同的绝缘解决方案是如何强大的水分损害，有相当大的不确定性，在边界条件和材料属性。第三，将探索水分风险评估的新方法。“水分安全系数”可描述绝缘SMW对极端事件（如洪水）的弹性。有可能开发一种全新的实验室测试来评估绝缘解决方案。这项研究的潜在优势来自于在最先进的湿热试验设施中收集高质量的原始数据，以验证模型的结果。