DL E&C Achieves Highest Grade in Interfloor Noise On-Site Performance Verification... Also Applied to Bukgajwa 6

First Construction Company to Receive Highest Performance Grade Recognition in Actual Apartment Outside Testing Room

The floor impact sound performance rating is being measured at a new apartment construction site in Pyeongtaek, Gyeonggi-do.

[Asia Economy Reporter Onyu Lim] DL E&C (formerly Daelim Industrial) announced on the 10th that it conducted a floor impact sound performance evaluation at an apartment site and became the first construction company to be recognized with the highest performance grade. DL E&C consolidated 12 patented noise reduction technologies it developed independently and involved PhD-level researchers in architectural structures and materials, as well as acoustics experts, to complete the 'D-Silent floor structure.' The technology was developed by re-examining all areas related to inter-floor noise from the ground up, including structural systems, building materials, and soundproofing materials.

◆ Verified inter-floor noise reduction performance at an actual apartment site and recognized as the highest existing performance

Korea Land and Housing Corporation (LH) conducted a floor impact sound performance evaluation at DL E&C’s e-Pyeonhansesang apartment site in Pyeongtaek, Gyeonggi Province, using a bang machine, impact ball, and tapping machine at the end of last month. The evaluation results recognized that this floor structure secured floor impact sound insulation performance of Grade 1 for lightweight impact sound and Grade 2 for heavyweight impact sound. According to on-site performance evaluation standards, Grade 2 for heavyweight impact sound corresponds to the highest level of performance in Korea, and DL E&C is the first construction company to receive this recognition.

◆ Certified as the highest level of inter-floor noise reduction performance in Korea, reducing worries about inter-floor noise

The D-Silent floor structure achieves Grade 2 for heavyweight impact sound (41~43dB), which is similar to the noise reduction performance of a household air conditioner's low-noise operation mode. Most existing apartments meet the legal standard of Grade 4 for heavyweight impact sound. Applying the technology developed by DL E&C can reduce the noise perceived by the human ear to about half compared to Grade 4 (48~50dB) for heavyweight impact sound. Notably, this technology was recognized for its noise insulation performance at an actual site rather than in a laboratory, and it is expected to contribute to resolving residents' complaints in the future. Currently, when a Grade 2 heavyweight impact sound floor structure evaluated in a laboratory is measured at an actual site, the results mostly correspond to Grade 3~4 for heavyweight impact sound. This indicates a significant difference between laboratory and actual apartment measurements. According to a research report published by Professor Jin-Yong Jeon of Hanyang University (Survey on Inter-floor Noise in Multi-family Housing), only 20% of residents were satisfied at Grade 4 for heavyweight impact sound, whereas Grade 2 is predicted to satisfy up to 60% of residents.

◆ Ministry of Land, Infrastructure and Transport considering changing to a post-completion verification system

In 2019, the Ministry of Land, Infrastructure and Transport and the Board of Audit and Inspection conducted floor impact sound measurements at a total of 28 sites of LH and private construction companies nearing completion to investigate the actual state of inter-floor noise. The results showed that 96% of cases had performance degradation compared to laboratory performance grades, and 60% did not meet the minimum performance standard of Grade 4. Accordingly, the Ministry of Land, Infrastructure and Transport is considering changing the current 'pre-approval system' for floor impact sound insulation performance to a 'post-completion verification system' after apartment completion.

◆ D-Silent floor structure filters inter-floor noise in five stages

The D-Silent floor structure, recognized as the highest level of inter-floor noise reduction performance in Korea, was completed as a five-stage sound insulation structure by consolidating 12 patented technologies owned by DL E&C. The floor where residents directly live is given cushioning performance to primarily mitigate impact. Then, a high-performance crack-resistant special mortar suppresses impact vibrations, followed by a double air-layer floor cushioning material developed through a technology partnership with BASF in Germany, which absorbs impact once again. Finally, the fourth and fifth stages apply special mortar and vibration-proof concrete slabs to capture residual vibrations.

◆ Focused investment in noise reduction technology for 18 years, developing 17 patented technologies

DL E&C has been conducting research on inter-floor noise since 2003, continuing for 18 years. In 2006, it established the first architectural environment research center in Korea capable of verifying housing performance and has conducted various studies. Based on this, it developed 17 patented technologies related to noise reduction, including 12 patents specifically for inter-floor noise. Currently, DL E&C possesses top-level technological capabilities in related fields such as structural systems that minimize vibration transmission and materials that absorb vibration and impact.

Professor Sang-Hyun Lee of Dankook University, an authority in building seismic and vibration fields who participated as a technical advisor for DL E&C, stated, “The D-Silent floor structure is a technology that reduces impact loads in five stages from finishing materials to slabs, not only using soundproofing materials, effectively improving noise and vibration.” He added, “We expect to gradually solve the inter-floor noise problem, which has been a perennial issue in apartments.”

DL E&C plans to commercialize the D-Silent floor structure at sites approved for construction starting in 2022. It also intends to apply it to the Bukgajwa 6 District housing reconstruction complex, which is currently pursuing orders. Along with the floor structure technology, DL E&C proposed innovative living noise reduction technologies such as a composite column structural design, an inter-floor noise alert system, and a fan-separated range hood system that minimizes noise for Bukgajwa 6 District.

This content was produced with the assistance of AI translation services.