Accelerate the innovation of insulation wall materials to avoid future "pain of losing sheep."

On April 27, the Beijing Municipal Commission of Housing and Urban-Rural Development issued the "Notice on Conducting Defect Investigation of Existing Residential External Wall Insulation Systems" (hereinafter referred to as the "Notice"). The "Notice" requires a comprehensive investigation of quality defects and damages such as cracking, hollowing, deformation, water seepage, and falling off of the external insulation system according to the warranty period of the external wall insulation, and to implement the responsibilities for inspection, testing, evaluation, and repair of the external insulation project.

After the release of the "Notice", some industry insiders highly praised it, believing that the "Notice" focuses on issues such as external wall falling off in current housing quality, has strong guidance, and helps ensure the safety of residential use; however, some pointed out that while the "Notice" brings joy in "repairing the fence", we must not forget the pain of "losing the sheep" and should quickly improve the standards for external wall insulation materials in buildings under construction and planning, and accelerate the orderly and effective promotion of innovative materials.

The three major "pain points" of external wall insulation

Earlier this year, the Beijing Municipal Commission of Housing and Urban-Rural Development announced penalties for two cases of external wall insulation board falling off.

The first case occurred in May 2019, where the decorative surface of the chimney in the boiler room of the Changping District Park Yueli commercial housing project fell off, covering an area of about 50 square meters. The Beijing Municipal Commission of Housing and Urban-Rural Development ordered the construction unit to organize the responsible unit to rectify thoroughly. At the same time, according to relevant regulations, a fine of 151,200 yuan was imposed on the professional contracting and general contracting units of the external wall insulation board; a fine of 100,000 yuan was imposed on the supervision unit. A fine of 15,120 yuan was imposed on the project leader of the professional contracting unit of the external wall insulation board and the project leader of the general contracting unit; a fine of 10,000 yuan was imposed on the chief supervising engineer. According to relevant regulations, bad credit scoring was applied to the professional contracting unit of the external wall insulation board, the general contracting unit, the supervision unit, and their responsible personnel.

The second case occurred in August 2019, where the insulation layer of Building 3 in the Chaoyang District Changyiyuan community fell off, covering an area of about 600 square meters, causing damage to 21 motor vehicles. The Beijing Municipal Commission of Housing and Urban-Rural Development ordered the construction unit to organize the responsible unit to rectify thoroughly, and imposed a fine of 36,400 yuan on the labor contracting unit for external wall insulation; a fine of 91,700 yuan on the general contracting unit; and a fine of 100,000 yuan on the supervision unit. A fine of 3,600 yuan was imposed on the project leader of the labor contracting unit for external wall insulation; a fine of 9,200 yuan was imposed on the project leader of the construction unit; a fine of 10,000 yuan was imposed on the chief supervising engineer; and according to relevant regulations, bad credit scoring was applied to the labor contracting unit for external wall insulation, the general contracting unit, the supervision unit, and their responsible personnel.

"Cracking, hollowing, falling off; insulation but not fireproof; fireproof but unable to meet energy-saving building insulation requirements, these have become the three major 'pain points' in the external wall insulation industry," said industry insiders.

The "chicken rib effect" of common insulation materials

"Not using it is confusing, using it has hidden dangers." Through visits, we found that the "chicken rib effect" of commonly used insulation materials is prominent.

First is insulation mortar. Due to the addition of a large amount of inorganic materials, insulation mortar has non-combustible characteristics, once filling a gap in the industry and gradually being recognized by the market. Insulation mortar has a high thermal conductivity coefficient and is mainly used in southern China, contributing to building energy conservation.

However, the technical defects of insulation mortar are gradually becoming apparent: first, insulation mortar needs to be mixed and stirred on-site, which is difficult to supervise due to factors such as workers' operational levels, climatic conditions, and construction site conditions, making it easy to hide dangers; second, problems such as falling off, cracking, water seepage, and hollowing of insulation mortar are common, severely affecting building quality and safety. Finally, by 2020, the total energy consumption of buildings in society must achieve a total goal of 75% energy conservation, which insulation mortar cannot achieve.

In response to the problems of insulation mortar, Beijing and Jiangsu have taken the lead in banning the use of insulation mortar in the country. Some places have followed suit, requiring buildings to prohibit, restrict, or use insulation mortar cautiously.

Next is insulation rock wool. The main component of rock wool is inorganic material, which has good fire resistance. However, the production process of insulation rock wool consumes a large amount of ecological energy, and environmental pollution issues have been repeatedly exposed. Some rock wool production areas have been named by the National Ecological and Environmental Protection Department multiple times, with deadlines for rectification. To meet environmental standards, capable rock wool companies continuously improve and update production equipment, eliminating backward production capacity and technology, resulting in a significant increase in the cost of insulation rock wool, making its price advantage no longer obvious.

In addition, ordinary insulation rock wool also has low tensile strength; under humid and hot conditions, its dimensions are unstable, leading to hollowing and falling off; the fibers of bare rock wool boards are interconnected with air, making them prone to fluffing and swelling under thermal expansion and contraction and negative wind pressure.

At the end of 2017, Kaifeng, Henan began to restrict the use of thin plastered external wall insulation systems with rock wool boards. The head of the city's housing and urban-rural development bureau stated: "Domestic rock wool has obvious technical defects, mainly reflected in tensile strength and water absorption. Due to the hydrophobic nature of rock wool, its application in external wall insulation easily leads to cavities, powdering, and falling off, thus failing to achieve the desired insulation effect." In 2019, Hunan Province banned the promotion of rock wool insulation materials, stating: "The thin plastered external wall insulation system with rock wool boards does not meet the climatic characteristics of Hunan Province and has safety hazards; rock wool and glass wool products without keel and protective panels in internal insulation systems do not meet standards and pose health risks to humans."

Then there are organic materials such as XPS polystyrene extruded boards, which have become "accomplices" in multiple fires and are being called for a ban by the industry.

High-quality development urgently requires industry "innovation"

"The external wall insulation industry must first solve the 'thick-skinned' problem, otherwise incidents of falling off and injuring people or damaging property may become more serious," multiple experts expressed their concerns.

Yang Yuzhong, chief engineer of the Energy and Environment Testing Center of the China Academy of Building Research, pointed out that in the past two to three years, the standards related to external wall energy conservation and insulation have changed significantly. With the increasing requirements for building energy conservation, the thickness of building insulation layers has correspondingly increased. For example, the requirements for external wall insulation in nearly zero-energy buildings have increased from the current 60mm-80mm to over 200mm, which poses higher safety risks for the construction quality of external wall insulation.

"The external wall insulation layer is getting heavier, and the improvement of construction technology is insufficient, leading to conflicts between insulation energy conservation and secure installation," said Professor Meng Yang from Shandong Jianzhu University. "Currently, the external wall insulation layer weighs nearly 20 kilograms per square meter, and the fixed requirements will also increase, but many workers on-site are accustomed to the previously simpler operations, making it inevitable that some local fixings are not very secure."

How to break out of the chaos and predicament of external wall insulation projects? The only way out is "innovation in wall materials." A research team formed by Professor Zheng Juanrong from the School of Civil Engineering at Zhengzhou University and Senior Engineer Zhao Zhenbo from Zhengzhou University of Technology's High-tech Materials Science and Technology Co., Ltd. holds this view. After several years of hard work, they have developed a new product, "inorganic plasticized microporous insulation board," which has been identified by the National Building Energy Efficiency Quality Supervision and Inspection Center: the product has a dry density of less than 130kg/m3, a thermal conductivity of less than 0.045W/(m·K), a compressive strength greater than 0.4MPa, a water absorption rate of less than 3%, and a combustion performance of Class A. Currently, this product has entered the "PKPM" design software of major architectural design institutes in Henan Province, becoming the first choice for designers. The originally designed insulation mortar or rock wool board has also seen a large number of engineering design changes, causing a significant response in the Henan construction market. It is widely believed that a way out has been found and the predicament has been overcome.

Industry insiders also pointed out that with the iteration and update of building insulation materials, the country should accelerate the improvement and adjustment of relevant policies and regulations, providing a platform for new materials to showcase their capabilities. It should not always revolve around the original few types of insulation wall materials. New materials that have matured in technology and have gained market recognition should be promoted for use as soon as possible. The government should also provide policy encouragement and financial support to enterprises developing and producing new external wall insulation materials, promoting a good trend of industry-leading research and innovation.

At the same time, the lifelong accountability system for building quality should be implemented as soon as possible. A responsibility accountability system should be formed where those who develop are responsible, those who produce are responsible, those who build are responsible, those who supervise are responsible, and those who accept are responsible, strengthening the sense of responsibility among various departments and promoting the use of new materials and new products.

Not long ago, the State Administration for Market Regulation issued the "National Key Industrial Product Quality and Safety Supervision Catalog (2020 Edition)," listing external wall insulation materials in the national key industrial product supervision catalog. It requires that "based on safety assessments, measures such as enhanced supervision and inspection, production licensing, law enforcement against counterfeiting, certification and accreditation, risk monitoring, and recall of defective products should be classified and taken according to the level of product quality and safety risk." It is believed that this will force the insulation wall material industry to accelerate product and technology innovation.

(Transferred from China Building Materials News Network)