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

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

2) The Plaintiffs purchased construction project management services from the Defendant as joint water supply unit, such as exercising the supervisory authority on construction phase of D apartment construction works (hereinafter “instant apartment construction works,” and “the instant construction works”). (B) The Board of Audit and Inspection conducted audit on the actual status of operation of the noise system between floors of apartment houses, including the pre-approval of floor shock structure, performance evaluation, etc., for apartment construction works implemented by the Defendant, etc. from September 3, 2018 to January 18, 2019. (3) The Board of Audit and Inspection conducted an audit on the operation of the noise reduction system between floors of apartment houses.

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) As a result of testing the appropriateness of quality of buffer materials from among the production companies that supplied buffer materials to the top three companies in the order of construction among the production companies that supplied buffer materials to the Defendant 42 sites, the results of testing the appropriateness of quality of buffer materials are as follows: the recognition of buffer materials brought into two sites and the criteria for management (No. 2019-622, Nov. 8, 2019, the Ministry of Land, Transport and Maritime Affairs No. 2019-622, Jun. 22,