Prefabricated Buildings | Li Xiaoyang on Developing a Standardized Construction System Through Standardization Reform

On November 9, 2018, at the 3rd China Engineering Construction Standardization Summit Forum, jointly organized by the China Association for Standardization of Engineering Construction, the Institute of Standards and Quotas of the Ministry of Housing and Urban-Rural Development, China Construction Science and Technology Group, China Academy of Building Research Co., Ltd., and the People’s Government of Wujin District, Changzhou City, Li Xiaoyang, Deputy Director of the Standards and Specifications Department at China Academy of Building Research Co., Ltd., delivered a speech titled “Exploration of the Construction of Prefabricated Building Standard System from the Perspective of Standardization Reform.” The transcript of his speech is shared below:

Dear leaders and guests, I am honored to discuss the integration of standardization and industrialization. My speech is titled “Exploration of the Construction of Prefabricated Building Standard System from the Perspective of Standardization Reform.” During the 13th Five-Year Plan period, many experts have supported our research efforts, and I express my sincere gratitude. Please feel free to correct me if I make any errors.

My speech will cover four main areas:

1. Engineering Construction Standard Working Environment

Currently, two contrasting views exist: some see repetition, overlap, and contradictions in standards, while frontline engineering workers often feel that there are too few standards to meet the needs of construction and supervision. Since the 18th National Congress of the Communist Party of China, efforts to improve standardization have accelerated. The State Council launched the “Deepening Standardization Work Reform Plan,” and the Ministry of Housing and Urban-Rural Development issued a series of plans outlining five key functions: mandatory standards set the baseline, recommended standards cover fundamentals, industry standards fill gaps, group standards drive innovation, and enterprise standards enhance quality.

Within the reform plan, a crucial goal is to break the government’s monopoly on standard supply, establishing a new system where government leadership and market-driven independent formulation coexist. This aims to create a unified, coordinated, and efficiently operated framework with shared governance between government and market actors.

2. Overview of Prefabricated Building Standards

Firstly, the United States: The 2010 US National Standard Strategy emphasized strengthening public interest, boosting industrial competitiveness, and promoting a liberalized global trade system. This differs from the current trade war context, as the US standard system sets clear goals and strategies, highlighting American technological leadership in the global standards arena. In 1976, the US enacted the National Industrial Housing Construction and Safety Act, and the Federal Department of Housing and Urban Development issued related standards including the PCI Designer Series Handbook and concrete-related regulations.

Secondly, Sweden: Sweden focuses on building universal components. Their foundational work in module coordination has led to the establishment of highly standardized and high-quality industrial standards.

Thirdly, Japan: Japan has comprehensive regulations for industrial residential performance certification. Their product standards cover industrialized and socialized production of residential components, accounting for over 80% of total standards. Systems exist for component size and functionality, such as the “Specification for Prefabricated Reinforced Concrete Structures,” which includes a series of standards for prefabricated and assembled concrete.

In summary, foreign prefabricated building standards often lack a clearly defined system but employ systems engineering methods extensively. They have developed numerous standards for steel and prefabricated concrete structures.

China’s current prefabricated building standards mainly consist of three major systems: prefabricated concrete structure standards, steel structure building standards, and wooden structure building standards. The development and revision of prefabricated concrete standards are accelerating, with various regions developing local standards to continuously improve the system.

However, our standards also face four main shortcomings:

• Most existing standards are design-focused, lacking comprehensive coverage of the entire industrialized building process, prefabricated housing, and industry chain.
• Traditional architecture standards touch on prefabricated construction but are incomplete, scattered, and lack systematic coordination, hindering integration with industrialized construction and causing operational inconsistencies. Existing component standards lack sufficient universality for prefabricated buildings.
• Standards for collaborative work and detailed design are insufficient; internal standardization for pipelines and interfaces is missing.
• Coordination between engineering standards and product standards is inadequate, creating barriers to large-scale reproducible development.

3. Construction of the Prefabricated Standard System

Guided by thoughtful planning, we emphasize five key aspects in system construction:

• First, the standard system must align and coordinate with our building product systems.
• Second, it should comply with current standardization reforms, balancing government-led standard setting with market-driven standards, and integrate with technical, product, and management systems. This includes macro-level standard planning, effective implementation, supervision, and fostering innovation through standards.

During the 13th Five-Year Plan, we established a new standard system characterized by:

• Coverage of the entire process and main industrial chain of prefabricated buildings;
• A systematic, coordinated, progressive, applicable, and forward-looking approach;
• Use of mandatory regulations as constraints, general basic standards as guidance, and specialized technical standards as support;
• Incorporation of both market and government standards.

Basic and key technical standards were formulated and applied in standard system development. Throughout this process, we adhered to five foundational principles:

1. Comprehensive and systematic coverage focusing on key areas, encompassing the entire industry chain for current and future periods.
2. Clear hierarchy and planning levels.
3. Openness, compatibility, and dynamic optimization, emphasizing high-end system standards with flexibility for future development.
4. Practicality, innovation, and leadership that meet current rapid development needs, address bottlenecks, and align with international standards.
5. Implementation of reforms to promote coordinated growth.

Our system construction plan involves:

1. Theoretical research to develop an applicable framework for standard specification systems;
2. Current situation and demand analysis;
3. Division into sub-standard systems such as concrete, steel structure, wood structure, building equipment, etc., followed by system optimization and integration across the entire industry chain.

We apply four architectural industrialization theories:

• Systems Engineering Theory;
• Hall’s Three-Dimensional Structure Theory;
• Process Management Theory;
• Systems Engineering Theory (reiterated for emphasis).

Hall’s theory extends our model into three dimensions by analyzing construction processes. Importantly, the system is dynamic and evolving. We have conducted focused analysis and modeling of prefabricated building standard system requirements, decomposed system missions, modeled requirements, and evaluated management, assessment, and verification aspects. Our analysis includes element identification for real-world standards, domestic and international scenario comparisons, and mathematical modeling.

In summary, we propose four requirement dimensions:

• Practical problems: Although many standards exist, they are scattered and require sorting, evaluation, and improvement.
• Element recognition: Emphasizing industrialization concepts, modular coordination, design standardization of interior and mechanical/electrical pipelines, and interface standardization.
• Foreign scenarios: Developing a multi-component universal building system based on universal components.
• Mathematical modeling: Covering the entire construction process and extending to operation and maintenance phases.

Our standard system framework, based on Hall’s Three-Dimensional Structure Theory, includes:

• Standardized design: architectural, structural, and mechanical/electrical design;
• Industrial production: production of parts and auxiliary materials;
• Assembly construction: main structure construction, mechanical/electrical installation, and decoration;
• Operation and maintenance: component upkeep and reinforcement techniques;
• Cost and management: prefabricated building evaluation, component certification, quota setting, and information management.

Our overall system divides into two major parts:

• Core standard system: standards directly related to prefabricated buildings;
• Auxiliary standard system: universal standards supporting prefabricated buildings.

The core system includes sub-systems such as the basic bow-shaped sub-standard system, concrete structure system, steel structure system, wood structure system, building design, building equipment, decoration and renovation, and information systems. For example, the steel structure system covers design, production, construction acceptance, and maintenance. The enclosure system is divided into metal, concrete, door/window curtain walls, wooden enclosures, and others applicable to prefabricated buildings.

Integration of sub-systems is crucial after their establishment. This approach follows systems engineering theory, decomposing the system mission and goals into manageable units, then integrating and adjusting based on underlying standardization requirements and resource elements. A key principle is emphasizing new materials and technologies while aggregating standardization needs from frontline construction and operation.

Using prefabricated concrete (PC) as an example, we design the sub-standard system by considering standard levels, attributes, and standardization elements. The PC sub-system divides into six major parts: design, construction, production and acceptance, operation and maintenance, demolition and reuse, and informatization. Each part features three levels: mandatory specifications, general technical standards, and professional technical standards. Each stage centers around prefabricated construction methods with the goal of achieving the five modernizations.

The prefabricated concrete sub-standard system builds on the basic public standard system. Its first dimension follows project processes, including design, production, dismantling, and reuse. Some standards span multiple stages, leading us to define a multi-process standard category.

The second dimension distinguishes general and specific standards within the first dimension. The system is presented by combining these two dimensions, while other attribute elements are labeled within the system table. Additionally, we have developed thematic standard sub-systems focused on key assembly factors such as the main structure, connection methods, and module templates.

This table organizes the standard system hierarchy. The first dimension is mandatory specifications, for which we aim to develop technical specifications for prefabricated concrete, currently included in our standard design. The second dimension includes basic standards covering concrete reliability, drawing, terminology, seismic terms, classification, and general standards. Specialized standards such as group and professional standards follow an open model.

Finally, I emphasize that through system construction and standardization tree development—including branch separation—our results will mature alongside technological and industrial progress.

4. Current Status of Key Standard Development for Prefabricated Buildings

Domestic enterprises and universities have been highly responsive to innovation and market demands for prefabricated building standards. Over 60 standards were developed during the 13th Five-Year Plan period for special projects. Government standards accounted for more than 40%, group standards also exceeded 40%, and enterprise standards made up the remaining 10%, aligning with current standard reform efforts.

Let me introduce two developed standards:

• “Code for Construction and Acceptance of Prefabricated Concrete Structures” — designed to establish universal construction and quality acceptance standards for prefabricated concrete structures. It complements existing acceptance specifications and introduces standardized engineering acceptance technology suitable for current trends and demands.
• “Standard for Storage of Building Engineering Information Models” — a national standard covering data storage, transmission, and utilization throughout the entire lifecycle of construction projects. This standard aims to close gaps in our application technology and advance our capabilities comprehensively.

In conclusion, I would like to stress that today’s presentation reflects preliminary concepts regarding the prefabricated building standard system, representing the collective efforts of our expert team. I look forward to collaborating with enterprises and research institutions to explore and refine these standards in practice. Our next step is to achieve comprehensive coverage of the industrial chain and the entire prefabricated building process through continued standard development. Importantly, we uphold principles of consultation, co-construction, and sharing, working together to advance China’s prefabricated building standards. Thank you.

Article Source: Building Economy, Building Economy and Management

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