ABSTRACT
A shortage of housing is a prominent issue across the globe. Traditional on-site construction methods seem too inefficient to meet the increasing housing demand. As a solution, many countries, including the United States, Germany, Singapore, Japan, Hong Kong and Australia, have introduced off-site manufacturing methods to increase the housing supply. Different from the traditional way of on-site construction, off-site manufacturing is a technique that involves manufacturing building components in a controlled environment. Despite strong government support and industry attempts to increase off-site manufacturing, the current building consenting and inspection processes in New Zealand have significant quality-related issues. Therefore, this study aimed to identify the gaps in current quality assurance processes used in off-site manufacturing and recommend a framework in order to gain credibility and the acceptance of the construction market. The study collected qualitative data from industry experts (e.g., developers, architects, engineers, project managers, quantity surveyors, head contractors and council officers) who had significant experience in current quality assurance regimes in New Zealand prefabrication construction. The key themes for designing the proposed framework were generated using content analysis of the primary data collected from semi-structured interviews with industry experts. The study has found that standardisation in off-shore products regarding the New Zealand Building Code remains the biggest challenge in the consenting process. Quality assurance and inspection test plans are the developer’s responsibility and are typically provided by third-party inspectors. In this post-Covid-19 world-building, consent authorities rely heavily on third-party inspection companies that apply more rigorous auditing. Essentially, the most important parts of quality assurance are to have an experienced team and to adopt a holistic approach by engaging stakeholders early in the design stage. The stakeholders should consider recommendations for mandatory after-service insurance to ensure end-customer interests are protected. The findings of this study can contribute to the early engagement of different stakeholders to ensure overseas manufacturing of building components meets New Zealand quality standards. It is expected that the new quality assurance framework would help to promote off-site manufacturing for the New Zealand housing sector.
ABSTRACT
The building sector continues to play an essential role in reducing worldwide energy consumption. The reduced consumption is accompanied by stricter regulation for the thermotechnical design of the building envelope. The redefined nearly Zero Energy Building levels that will come into force for each member state will pressure designers to rethink the constructive details so that mandatory levels can be reached, without increasing the construction costs over an optimum level but at the same time reducing greenhouse gas emissions. The paper aims to illustrate the main conclusions obtained in assessing the thermo-energy performance of a steel-framed building representing a holistically designed modular laboratory located in a moderate continental temperate climate, characteristic of the south-eastern part of the Pannonian Depression with some sub-Mediterranean influences. An extensive numerical simulation of the main junctions was performed. The thermal performance was established in terms of the main parameters, the adjusted thermal resistances and global thermal insulation coefficient. Further on, the energy consumption for heating was established, and the associated energy rating was in compliance with the Romanian regulations. A parametric study was done to illustrate the energy performance of the investigated case in the five representative climatic zones from Romania. An important conclusion of the research indicates that an emphasis must be placed on the thermotechnical design of Light Steel Framed solutions against increased thermal bridge areas caused by the steel’s high thermal conductivity for all building components to reach nZEB levels. Nevertheless, the results indicate an exemplary behaviour compared to classical solutions, but at the same time, the need for an iterative redesign so that all thermo-energy performance indicators are achieved.