1. All of the plaintiffs' claims are dismissed.

2. The costs of lawsuit are assessed against the plaintiffs.

1. Details of disposition;

A. The Plaintiffs are construction technology service providers providing comprehensive supervision services.

2) The Plaintiffs jointly performed construction project management services, including vicarious performance of supervisory authority on construction phase for C Apartment Construction Works (hereinafter “the instant apartment construction work,” and “the instant construction work”), by being awarded a contract from the Defendant (i.e., the service period from Aug. 16, 2016 to Oct. 24, 2018; (ii) Plaintiff Co., Ltd., Ltd.; and (iii) Plaintiff Co., Ltd., B20%; hereinafter “Stock”). (ii) The Board of Audit and Inspection conducted an audit on the operation of the noise reduction system between floors of the Board of Audit and Inspection (1) from Sept. 3, 2018 to Jan. 18, 2019.

2) The result of the Board of Audit and Inspection’s measurement of noise between floors for the total 191 households of apartment units scheduled to move in at the completion stage showed that the 184 generation was lower than the actual performance grade which was approved in advance, and that the 114 generation among them was below the minimum performance standard.

3) As a result of the inspection conducted by the Board of Audit and Inspection of the noise-preventive performance of the sample generation prior to the execution on the 89 site where the sample generation was located in the 115 construction sites conducted by the Defendant, it was confirmed that the noise performance was measured after the 31 construction sites including the instant construction sites, which did not measure the performance of the sample generation noise or 2 to 382 days after the commencement of the construction works.

4) In addition, as a result of the inspection conducted after the Board of Audit and Inspection confirmed whether buffer materials brought into the site for 99 sites meet the quality standards, it started the construction before the issuance of a buffer quality inspection report from the 57 construction sites (58%) including the instant construction site. In particular, 42 out of the Defendant 55 sites are buffer materials.