Replace the existing deteriorated water line with new polyethylene pipe (Higher performance polyethylene, HPPE) (Approx. 400meter) including gate valves, fittings, and related components, at Chimuwan Tank Farm #1. Work includes necessary soil preparation for trenching and installation. Restoration work must be conducted on the site affected by this project. Temporary barricade shall be provided by the contractor during the construction to prevent other occupancy area from construction dust and security. Per accepted Accident Hazard Analysis. When installing the new system, ensure that no other engineering disciplines are affected. If any disruption occurs, restore the impacted areas to their original condition at no additional cost to the government. Obtain government approval prior to making any changes. Test and verify that the new system is operational following installation. Excavate/dispose and backfill with compaction and prepare the ground to required bedding surface for new structure. Replace existing pavement paint markings, asphalt concrete pavement with new including 50mm thick surface course, 50mm thick binder course, 150mm thick sub base course, 150mm thick base course and restore portion of existing structure affected by this project. All above ground materials of the water line and fittings shall be deterioration and corrosion resistant. After installation of new service water line, conduct hydrostatic test. Consider construction phasing to avoid water outages as much as possible and submit water outage plan with schedule prior to start of work for review/approval by DPW. The buildings can allow 8 hrs. maximum water interruptions from Monday to Friday per day. Provide 15 cm thick sand cushion all around water pipe and marking tape for metal reaction detector type. Provide concrete encasement of crossing of water line and sewer line as required. Provide concrete encasement if shallow depth of new pipe to avoid existing obstacles as required.
Provide marker pins and concrete markers for underground water pipe lines at the linear change points and straight lines for this project. Provide the steel plate across the board trench to secure for the safety traffic of the car on roadway as required. Provide shoring, including sheet piling to protect workmen, banks, adjacent paving, structures, fence line and utilities in accordance with Corps of Engineers manual EM 385-1-1 as required. Provide temporary drainage system to maintain existing storm drainage flow under construction as required. Provide rope off/barricade at all open trenches in accordance with standard construction procedures, to include hazardous/warning signs and perform traffic control with watchman and consider construction phasing to be able to use existing parking lot when under construction as much as possible.The construction areas shall be continuously illuminated during hours of darkness. Conduct sampling of suspect asbestos containing material (ACM), and lead-based paint (LBP) and submit report with laboratory analysis results. Sampling plans for ACM/LBP shall be submitted for government review prior to commencing testing. Restore pavement paint marking, reinforced concrete slab, concrete sidewalk, curb, curb/gutter and grass area with sodding. Contractor shall inform COR and fire department of any expected fire hydrant outrages and/or fire sprinkler outages at least 4 calendar days before the outage. Rock Excavation: If there are rock excavated with a size greater than 1/2 cubic meter in volume, a rock survey report & pictures shall be submitted quantifying the total volume of rock excavated. The rock removal will be accomplished by modification of task order. Consider installation of water distribution pattern (provide valve, valve boxes, fittings, tapped saddle valves backup temporary pipe and distribution pipe lines as required) to avoid water outage and submit water outage plan with schedule prior to start work for approval from the using agency. Conduct water quality test (bacteriological, lead, copper, etc.) for the existing water system as background. All potable water system (water service line and temporary line) materials and equipment (pipes, valves, fittings, fixtures, solder, etc.) shall be lead and copper free. Conduct water quality test for lead and copper in accordance with JEGS. Lead free materials defined by manufacture's test results are also subject for the lead and copper test unless manufacture test methods are performed IAW JEGS. The materials and equipment shall be isolated when conducting the test. Contractor shall provide sampling/testing methods to the Government for approval. Ensure that the test results meet the JEGS requirements, otherwise the materials shall not be used for potable water system. Disinfection procedures for potable water system shall be in accordance with “Torii Standard” (Disinfection Procedures for New Potable Water Line, etc…). New potable water system shall be completely installed, flushed, disinfected and satisfactory the absence of coliform bacteria and the general bacteria sample results received prior to connections to the existing distribution system for the Buildings #111, 114, 117 & 119. Conduct potable water quality test for total coliforms whenever a water outage or depressurization of the potable water system is happen. Install new 50 mm special polyethylene pipe (Higher performance polyethylene, HPPE) for prevent of damage from seismic. The polyethylene pipe shall be provided excellent seismic performance that flexibly follow the ground deformation caused by the earthquake. Connect each pipe using special fittings, tees and elbows to unite pipe line melt the joint with heat. Provide new gate valves and cast iron valve boxes. Provide new above ground water line with the hose bibb and pipe supports etc. to the building #111 & 114. After installation of the new water lines, remove and dispose of all existing underground water lines, valve, valve box and above ground water line with the hose bibb etc. Provide the temporary back up supply water pipe line with backflow preventer from near existing fire hydrant for the following buildings as required. (if water interruptions to exceed 8 hrs per day) Building #111, 114, 117 & 119.