A. The relationship between the parties 1) Plaintiff B is the studio of the second floor located at H in the Y in the Y in the Hasan-si (hereinafter “the studio of this case”).

The lessee who leased No. 104 of the first floor is the victim of the gas explosion accident that occurred in the above room as seen below. The Plaintiff C and D are the parents of the Plaintiff, and the Plaintiff E are the owners of the studio in this case. The Defendant F is the owner of the studio in this case. The Defendant G is the construction business operator who had done boiler facilities, water supply facilities, water leakage detection work, etc. for about 20 years prior to the trade name of the Plaintiff G.

B. On January 20, 201, Defendant F entrusted the construction of water leakage detection of the instant room to J on January 20, 201. As the J did not find water leakage points, Defendant G re-entrusted Defendant G with the introduction of J to re-scept the water leakage detection of the said room from January 15, 201 to January 17:30, 201. Defendant G used water detection devices at the time, discovered that water leakage was from the main underground pipelines of the instant room 104 to verify and confirm that water leakage was from the main underground pipelines of the instant room 104, which Plaintiff B leased by using water leakage detection devices at the time, and first 30 meters in depth from the central floor of the instant room 30 meters in depth. However, Defendant G was not found from water leakage in the upper part of the instant room 103 meters in depth.

3) Before performing the above excavation work, Defendant G moved gas sirens on the above kitchen. At that time, Defendant G found that the gas string connected to the above gas sirens was built of a structure connected to the fall and gas sirens from the floor below the above main wall, and that three gas strings out of the above studio building were moved to the inside of the building through each gas pipe, and that three gas strings out of the above studio building were moved to the outside of the wall No. 104, and the above excavation work started after Defendant F had Defendant F cover three valves out of the above gas tank.