27 of 49 Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements  Section 05: Earth Works, Pipe Works and Ground Improvement  Towing and pulling the floated pipeline onto place shall be executed in such manner not to overbend  the pipeline or to damage the pipeline in any other way.  Position of floated in place pipeline ready to submerge shall be checked by approved devices. All in- volved vessels shall be equipped with positioning systems and two way radios.  Divers on the pipeline shall communicate by means of a diver to boat communication system with  both the placement boats, which are towing the pipe into place, and the boat on the terminal end re- leasing the air. The divers shall advise the placement boats to move the pipe to right or left, or hold, so  as to keep the pipe on alignment as it reaches the bottom and also advise the air release operator when  to release the air to obtain descent of the pipe.  Submerging shall take place by gradually releasing air from this valve and allowing water to enter the  outfall at the shore end. The rate of descent shall be controlled by the air release valve at the terminal  end and shall never exceed the calculated rate of descent.  Air shall be released in a series of short bursts with sufficient time between bursts to receive commu- nication from the divers.  Provision shall be made to preclude entrapment of air in a high spot after submerging.  In case the Contractor uses the “float and sink” method for placing single sections separately on the  bottom, the pipeline will be laid from the offshore barge.  The section will be equipped with buoyancy tanks or parachutes or balloons to enable the control of  the lowering after the section is filled with water. Practically, the pipe section can be eventually float- ed in open conditions, provided that it is supported by the necessary number of buoyancy tanks. When  in position, the pipe or the buoyancy tanks are flooded and the pipe is lowered into the trench or onthe  bottom. The lowering is followed by divers which take care that the section end comes in contact with  the section already on the bottom. After a diver has confirmed by diver to boat communication that the two pipe ends are in close prox- imity to each other and relatively aligned, the jointing team provides to close the joint by bolting the  flanges.  The jointing shall be made before the buoyancy tanks are released, in order to keep the incoming sec- tion “light” and facilitate the matching of the flanges.  As mentioned, the underwater jointing may be realized with compression couplings, which do not re- quire a particular precision in bringing the sections together.  installation and jointing of the section shall be facilitated if necessary by the use of sand bags placed  under the pipe ends to provide the necessary alignment.  The whole submerging procedure shall be monitored by underwater video cameras transmitting online  to a screen on the boat at the terminal. In case the pipeline section cannot be positioned properly by the  towing boats even in submerged status, the pipe section shall be refloated by pumping air into the pipe  from the terminal end.  Subsequently the refloated pipe section has to be positioned and submerged again. be made by means  of air lift bags with lifting straps.  5.3.10 Testing of Pipelines  5.3.10.1 Precautions Prior to Testing Pipelines  Before testing any pipeline, the Contractor shall ensure that it is anchored adequately and that thrusts  from bends, branch outlets or from the pipeline ends are transmitted to solid ground or to a suitable  temporary anchorage.  5_Vol3_d4.3_Section 5 Earth and pipe works_en_GIR_rev6.docx 