Method Statement For Pressure Testing -puttaluma.docx

DRY ZONE URBAN WATER AND SANITATION PROJECT-PUTTALUM WSS

METHOD STATEMENT FOR PRESSURE TESTING

NCC –SIERRA JV 1

GENERAL METHOD STATEMENT FOR PIPE LAYING

1. Pressure Testing of HDPE pipe lines   



   

             

The length of the pressure testing will be selected according to the laying schedule but maximum length for the pressure testing would be 1.0Km. Initially all the washouts and junction tees in selected testing length will be blocked using the concrete thrust blocks and Iron blank flanges. The lowest end of testing stretch will be blocked using the thrust blocks and prepared for water filling. Normally other end will be prepared for air releasing. If air valves are included for selected pressure testing stretch, these air valves will be used for air releasing process as shown in Fig.3.These air valves are checked whether it is working properly before filling water. Water from the natural water resources will be used for pressure testing and transported to the site by using water browsers. Laboratory tests will be carried out to find out the suitability of the water which is going to be used for pressure testing when selecting the natural water resources. Otherwise purified water from NWS&DB will be used. Pressure meters are fixed at lower level of pipe line and pressure pumps are placed on firm ground while filling water to pipe line The water would be slowly filled at the lowest end using booster pump until reaching the working pressure. Pressure testing is done in four phases Phase 1 Water will be pumped progressively to the pipe line till it reaches the required pressure (7bars). The system is properly ventilated during water filling and filling water volume is measured to make sure that line is full. After 24hrs,check and record the remaining pressure Phase 2 After 24hrs,water is pumped progressively to the line till it reaches the required pressure(12bars) Water filling is done every hour to maintain the 10 bar pressure. This pressure condition maintains within four hours and added water volume in each hour is recorded. Phase 3 After phase 2,line is kept 1 hour period without adding any water Phase 4 After phase 3, line pressure is dropped till it reaches the test pressure (11bar). Then this pressure condition is maintained 3hours without adding any water to the system This pressure is recorded according to interval defined in pressure testing form PE line The system is acceptable if recorded pressure drop is within the approved range

2

Release air Until continues flow of Water Pump Water Valve

Pump Air valve

End Cap

A/V Release Air

Release air Until Continues flow of Water Fig 03

3

Pump CapPump

13. Pressure Testing of upvc pipe lines   



  

  

The length of the pressure testing will be selected according to the laying schedule but maximum length for the pressure testing would be 1Km. Initially all the washouts and junction tees in selected testing length will be blocked using the concrete thrust blocks and Iron blank flanges. The lowest end of testing stretch will be blocked using the thrust blocks and prepared for water filling. Normally other end will be prepared for air releasing. If air valves are included for selected pressure testing stretch, these air valves will be used for air releasing process as shown in Fig.04. Water from the natural water resources will be used for pressure testing and transported to the site by using water browsers. Laboratory tests will be carried out to find out the suitability of the water which is going to be used for pressure testing when selecting the natural water resources. Otherwise purified water from NWS&DB will be used. The water would be slowly filled at the lowest end using booster pump until reaching the working pressure. It would be allowed to stand for 24 hours and tested. After completion of hydrostatic pressure test, leakage test will be carried out. The duration of the test would be two hour and the line should be pressurized to 1.5 x working pressure. After 2 hours water is pumped to the line by using hand pump or booster pump until pressure comes to 1.5 x working pressure and the pumped water quantity is measured. The minimum allowable leakage is calculated using the following formulae

Lm

=

S×D× (P1/2) 715,317

4

Release air Until continues flow of Water Pump Water Valve

Pump Air valve

End Cap

A/V Release Air

Release air Until Continues flow of Water Fig 04

5

Pump CapPump

Traffic Control and safety Condition   

Until Finished the testing, both ends are well secured with safety arrangement to avoid any damages to the pedestrian & vehicle uses in the road. The fits are well barricaded & in the night blinking lamps will be arranged whenever necessary. After get through the test, the test fits will be backfilled by removing the water inside the pipe. Attention will be taken for discharging water to avoid any damages to the private lands & structures.

Man Power and Equipments, Materials Man Power  Following manpower is needed for pressure Testing Pipe Fitter Driver for Boucer Unskilled labours

01 01 02

Equipments & Materials 

Following equipment are needed for blasting Pressure testing Machine Pressure Gauge Water Bowser/Water tank with Lorry End protection materials

6