DL E&C employees are measuring inter-floor noise in an apartment in Seoul (staged photo).

 

DL E&C announced on the 28th that it has developed a ‘grade 1 floor structure with low-inter-floor noise’ ready for immediate commercialization, meeting the strengthened legal standards and evaluation methods. The previously-developed grade 1 products faced limitations, such as construction problems and high costs, which prevented them from being introduced to actual sites. To solve these challenges, DL E&C integrated technologies across multiple fields – including noise, structure, materials and acoustics – and successfully developed a Grade 1 floor structure that can be commercialized in Korea.

 

DL E&C has improved the ‘D-Silent Floor’, a grade 2 floor structure that was previously developed by integrating 12 patented technologies, and completed grade 1 technology. First, it designed and applied finishing mortar and cushioning materials that distribute impact and minimize noise and vibration without impairing walking comfort and usability. A vibration-isolation pad was also placed between the foundation mortar and the slab to quickly disperse residual vibration, which greatly improved noise-blocking performance. 

 

The existing Grade 1 products had difficulties in commercialization because they applied multi-layer structural cushioning materials that used a combination of various materials. In addition to the increased cost caused by the procurement of various materials, defects that occurred during the complex installation of cushioning materials were also obstacles. DL E&C succeeded in simplifying the structure with high-performance composite materials for noise-insulation efficiency, reducing the installation process and maximizing commercialization. In addition, DL E&C unified the material procurement window, thereby achieved an appropriate cost and created conditions for cost-effectiveness, and stable and uniform quality suitable for large-scale construction.

DL E&C’s floor structure was certified as Grade 1 (lightweight and heavyweight) in evaluating the floor impact sound performance conducted by the LH Quality Testing and Accreditation Center, an accreditation agency designated by the MoLIT (Ministry of Land, Infrastructure and Transport). Grade 1 certification is awarded only when both heavyweight impact sound and lightweight impact sound transmitted to the lower floor are under 37dB. DL E&C’s noise-insulation performance achieved levels akin to library noise (around 35dB), surpassing the noise level of typical home air conditioners (38 to 48dB).

 

DL E&C was the first construction company in Korea that has established a technology research institute in 1980, and began research on inter-floor noise. In 2006, it established the largest facility for studying floor impact sound, and secured the grade 1 heavyweight structure of the highest performance in Korea at the standard testing laboratory in 2010. Since applying the high-performance cushioning materials related to inter-floor noise for the first time in 2016, DL E&C has been consistently striving to solve the problem of inter-floor noise, such as obtaining the industry’s first on-site certified grade 2 floor structure in 2021.

 

Through continuous R&D activities, DL E&C has secured this Grade 1 product, following the popular products, ‘D-Silent Floor Eco (Grade 1 in lightweight, and Grade 3 in heavyweight)’, and the high-performance product, ‘D-Silent Floor (Grade 1 in lightweight and Grade 2 in heavyweight). DL E&C is the only construction company that has secured all Grade 1 to Grade 3 inter-floor noise certified structures based on on-site certified evaluation criteria.

 

Chan-Hoon Han, a professor of architectural engineering at Chungbuk National University and an expert in architectural acoustics and inter-floor noise, said, “Grade 1 floor structure developed by DL E&C will demonstrate stable performance for reducing inter-floor noise even at large-scale construction sites based on differentiated technology. We expect it to greatly contribute to improving the living environment of residents in terms of reducing inter-floor noise.

 

Sang-Shin Park, the CEO of DL E&C explained, “This technology is meaningful as it is the only grade 1 floor structure that has overcome the existing limitations and can be commercialized immediately. As the only construction company with certified structures from grade 1 to 3, we will strive to provide customized technology for reducing inter-floor noise according to the conditions of the project site and the client.”