Quality failures in Energy- saving renovation projects in Northern China

Abstract

The building sector contributes to about one-third of the total energy consumption worldwide (Liu, Li, et al. 2020). In China, the proportion of building energy consumption has increased rapidly year-by-year (Zheng et al. 2019). More specifically, the energy consumption of the building sector may increase to about 35% by 2020. Therefore, achieving good performance in energy-saving renovation projects in existing residential buildings is essential for reducing energy consumption (Liu, Li, et al. 2020).

The energy-saving renovation of an existing building is a critical strategy in achieving a long-term energy goal in the Chinese context. In response to the high energy consumption, the Chinese government encourages that the energysaving renovation projects of the existing residential buildings should be widely carry out in Northern China (Chen et al. 2015). However, in China, building energy renovation projects are subjected to quality failures resulting in energy wastage, a decrease in the energy efficiency of the project, an increase in project cost, and thus negatively affecting the overall performance of the renovation projects. To sum up, the existence of quality failures has a negative impact on the energy performance of the buildings in energy-saving renovation projects, and they are threats to the projected benefits of development programmes. In order to avoid them happening in the future, it is essential to find and analyse the causes of quality failures in energysaving renovation projects of the existing residential buildings. Therefore, this thesis examines the causes of quality failures in building energy renovation projects in Northern China. The main research question is “What are the main causes of quality failures for the energy-saving renovation projects of existing residential buildings in Northern China?” Based on the main question above, four steps are taken for a deeper understanding of the causes of quality failures in energy-saving renovation projects of the existing residential buildings in Northern China.

The first step is to identify and analyse the quality failures in energy-saving renovation projects of the existing residential buildings. Namely, previous researches pay little attention to the identification of quality failures and their sources, likelihood, impacts, and causes in building energy renovation projects in Northern China. This thesis conducts a case study approach to establish a foundation and to support the development of a survey questionnaire. Five residential buildings in Hohhot (a Northern city in China) that meet the renovation requirements are selected on the criteria such as location, contract value, renovation size, construction companies, supervision companies and the current status of building energy renovation projects. Hohhot is the case city for data collection in this thesis. The implementation of energy-saving renovation has been applied in Hohhot since 2008, which is one of the pilot cities. The thesis identifies a total of 25 types of quality failure. The most common quality failures include ‘Incorrect installation of the steel nails’ ‘Incorrect size of the new window frame and door frame’, ‘Untreated wall around the new windows’, ‘Unqualified fire resistance of EPS boards’, ‘The detachment between the different EPS boards’, ‘Misalignment of the waterproof roof layer’, ‘Cracks of roof concrete’, ‘Uncleaned wall’, ‘Missing interface treating mortar’ and ‘Missing rivets’. The causes of these quality failures are workers’ defaults; inadequate checking procedures; incomplete construction site survey; inaccurate design work; fraud of construction companies; and inefficient cooperation between different departments. Thus, it is a vital step to provide knowledge about those construction behaviours, which are likely to lead to quality failures occurring.

The second step is to identify and analyse all the causes as the foundation for reducing quality failures. The novelty of this study lies in the fact that it explored and analysed the causes systematically from two main aspects in the context of China: the importance of a cause and the level of effort required to address a cause. Validated through interviews with experts, this thesis identifies 18 causes of quality failures in energy-saving renovation projects. Using both a questionnaire survey and a focus group, this thesis finds critical causes, which have a significant effect on construction quality. The detailed analysis of these causes in Northern China concludes that the “Incomplete construction site survey” is ranked as the highest level of the impacts on quality, and the most common cause is “Incomplete building information in projects”. In order to clearly understand the causes, it is essential to separate them based on the efforts required to tackle a cause. The “Working under high-cost pressure”, “Working under high-time pressure”, “Adverse natural conditions”, and “Fraud of construction companies” are external to projects at the macro scale, with a high level of required action for tackling the challenge. Action on the external cause is essential for reducing quality failures. The project coordinators cannot directly influence them because, by definition, external causes originate outside the project.

After the identification and analysis of the causes in the first and second steps of this thesis, the deeper insights from a quality management perspective are explored in the third step. Many causes of quality failures not only directly influence the construction quality, but also they interact in building energy renovation projects. Previous studies have predominantly identified and ranked causes without taking into account a network of different causes. There are both direct and indirect/underlying factors of influence. In order to explain how the intricate relationships among the causes affect the quality of building energy renovation projects, the interpretive structural modelling (ISM) and Matrix Impact Cross-reference Multiplication Applied to a Classification (MICMAC) techniques are applied. The information is offered about how quality is influenced by separate causes that have interactive relationships. The external causes remain associated with all internal causes. The study revealed that FOUR factors: “lack of experienced project managers,” “unauthorized changes in design documents,” “incomplete building information in projects,” and “poor onsite coordination” are root causes. Their reduction or elimination helps the solving of several other internal causes. On the other hand, causes including “Use of poor materials,” “Inadequate equipment performance,” and “Inaccurate design work” are known as the most direct causes. The implementation of quality management can ensure that quality failures are not only prevented in advance but also solved. Based on the quality management actions, management strategies were obtained by combining the hierarchy structure among causes. In the context of China, the quality management actions are identified from five perspectives, including people, materials, machines, design, and organization, based on previous research studies (Liu and Guo 2014; Li 2014b).

This thesis in the fourth step explores how the actors and their interactions affect and cause quality failures during the renovation policy implementation process. The implementation of the renovation policies can also affect the construction quality of energy renovation projects. Actors’ interaction is vital to a proper understanding of policy-processes and policy outcomes, which help explain the causes of quality failures from a policy perspective in building energy renovation projects. In existing studies, actors and their interactions during the renovation implementation seem too often neglected in the discussion about why quality failures occur. Based on the policy network theory, the actors’ interests and resources actors have in energysaving renovation projects are mapped. A comparative case study reveals what is done with the implementation of the renovation, and how the implementation of renovation brings about the causes of quality failures in building energy renovation projects. The public-private collaboration is a vital part of construction preparation and construction processes. Also, in terms of renovation funding, the residents’ involvement will have a hindrance to the implementation of the building energy renovation projects and affect the construction quality negatively. As a norm, local governments just focus on the construction time schedule rather than ensuring the technical conformance for energy-saving and thus addressing climate change.

This thesis mainly concludes the causes of quality failures in the building energy renovation projects. First, it is important to state that most of the quality failures can be avoided at the management level. The causes of quality failures possibly occur during the construction management processes, which affect the overall quality and energy performance, like incomplete construction site survey, poor checking procedures of supervisors, poor operational skilled workers. Second, some external causes originated at a policy level and outside the project, like working under highcost and high-time pressure, fraud of construction companies. The implementation of building energy renovation projects is considered as one of the main causes of quality failures. These two dimensions complement each other to analyse the causes of quality failures in energy-saving renovation projects at management and policy levels in Northern China. The contribution of this thesis is to illustrate the causes of quality failures at management and policy levels, and how the causes of quality failures happened in energy-saving renovation projects in Chinese context.