All new and reintroduced water lines must be cleaned, disinfected, flushed and must pass tests for chlorine. Proper system flushing international district energy. The flushing shall be accomplished during prearranged times under direction and supervision of the engineer. Arrangements for draining the flushed water to be made before starting the flushing process. Following is an industry best practice flushing procedure. Upon completion of satisfactory cleaning, chlorination, and flushing, the wt sp will take water samples for bacteriological tests. Inspection checklist pipeline inspection checklist.
Systems standard hydraulic piping flushing procedure sfpsflush0 page 3 of 6 prepared by. Keep the system circulation, using the system flushing pumps. Other necessary steps for complete water removal such as air blowing shall be carried out where required. Procedures for flushing water systems after a drinking water. Flushing and cleaning process lines and vessels during pre. There is a substantial amount of waste generated if the system requires draining upon completion of the flush. Valves are opened and closed slowly to prevent water hammer. Standard specifications online pipeline testing and disinfection 33 00 7 of three 3 pipe volumes of water shall be turned over in the lines being tested. The purpose of chemical flushing is to remove any dirts, debris, oil, grease, rust, scale, ect form the pipelines. The options detailed in this procedure for capping, swabbing, flushing and testing of water mains prior to disinfection ensures that the main is clean and clear of foreign material which will drastically reduce the time required.
If this occurs, sediments may plug aerators screens on faucets. Guide to flushing and precommission cleaning of pipework. The water quality will be as per approved parameters. Flushed water should be disposed out of the storm water drain or disposal tanks provided at site. All low point drains and vents of piping or equipment which may retain water must be opened. It has been determined that a flushing velocity of 2 fts combined with a volume of water equal to two 2 pipe lengths is sufficient for preflushing of the entire length of the water main. After installation is completed, the distribution system should be maintained by flushing at a minimum frequency of once per year. The graphic in figure 1 shows how the water flows to an open hydrant, using the conventional flushing method. About sites are placed on the flushing list annually based on the diameter of pipe, time and volume required to meet the minimum chlorine residual and bacteriological results. Flushing and disinfection of hot and cold water systems. Water main testing and disinfection procedures final. Water main must be disinfected in accordance with awwa c65114 standard, except where these procedures establish a higher standard. The volume,in litres, can be o btained by multiplying the length,width,and height up to the water level in metres and then multiply the result by.
Contractor shall clean and replacereinstall all strainer screens after the final cleaning and flushing procedure has passed the final test criteria noted herein. It is an essential maintenance process that is designed to extend the life of rotating. The system is the again refilled and dynamic flushing started. This line to have an overflow bypass to divert water overboard and a meter beyond the bypass in order to know volume of water pumped into line. Flushing procedure an overview sciencedirect topics. This method of flushing is easy to conduct by maintenance and operations crews, but requires a large amount of water and may not completely clean the pipe network.
It is the responsibility of the contractor to remove the flushing water. In new systems, the emphasis is on the removal of contaminants introduced during the manufacture, storage, field fabrication, and installation. University of washington mechanical facilities services. Flushing shall be performed through fully open flanges andor open pipe ends. To establish standard procedures for the cleaning, disinfection and bacteriological testing of county potable water mains. Flushing is conducted during periods of low water demand. Unless specified otherwise, the tap shall be made at the top of. All contamination preventive measures, pressure testing, preliminary flushing, chlorination, and bacteriological sampling of the water main shall. Flush from the highest elevation to the lowest, where possible following the normal flow direction of the system.
Ensuring that they perform as they should can be helped significantly by following the correct precommission cleaning and flushing procedures of the pipework systems at the prehandover. The increased flow rate scours the water pipe s inner walls and helps to remove buildup of naturally occurring debris and. Example procedure for flushing an actual 3 floor office building. Flushing pressure shall not exceed maximum operating pressure specified in pipe codes. Sfpsflush4 sawyer systems standard hydraulic flushing. Flush piping with water until effluent is clean and contains no visible particulate matter. Open the drain valves in the main lines and drain the water. Dead end lines will be flushed every three 3 months to remove sediment and reduce stagnant water. It is often difficult for contractors and others to determine the velocity at which the water is flowing through the main pipe. Water main flushing moves water systematically through sections of a drinking water distribution system, creating a scouring action to clean the line. The relative frequency and nature of these activities represent a potential contamination risk to water distribution systems if proper. Upon close observation, the central facility platform is visible in the background.
Fill the system with clean water and drain the water after 30 minutes of circulation. Water main testing and disinfection procedures final 09242019. Flushing water supply shall have sufficient capacity to produce a flow velocity of 6 fts in largest pipe size with pipe full. This picture shows the workspread used, as well as one of the well protector platforms. During the flushing process the drain valves shall be kept open while the pump is running, until the water appears clean. Any proper flush operation includes moving water at a high flow velocity. Disinfection procedure for water distribution lines. Inclusive in this standard are newly installed, replaced, and relocated water mains, along with water mains being returned to service after being out of service for a period of time. Based on the comment from the mechanical contractor, there is no way they reached the required velocity with a fire hydrant pushing water through a 16 pipe 1700 long. Disinfection procedure for water distribution lines summary. Standard practice for cleaning, flushing, and purification of.
This process specifies the use of potable water only for flushing and pressure testing. Wash spills and splashes on away with running water. During chemical flushing thin layer of surface of pipe wall will remove as well all the unnecessary contamination. This procedure includes all underground and above ground potable water lines for new construction projects and major renovation projects. Open the drain valves in the main lines and drain the water completely. Flow direction to be controlled with block valves before meter and on overboard line. Method of statement for cleaning flushing and passivation of. The intent of the program is to ensure compliance with the methods and procedures outlined in. Flushing through smaller openings, such as drains or vents, is not acceptable. Water can stagnate inside the building pipes and tanks. Corporation curb stop taps used for flushing, pressure testing, and disinfecting shall comply with service tap requirements for ductile iron pipe or c900 pvc pipe.
Copper tube to en 1057 tube size water volume flushing and disinfection of hot and cold water systems litres per metre run 15 x 0. Section 6 pipeline flushing, hydrostatic testing, and. Direct water away from traffic, pedestrians, underground utility vaults and private lands. Apr 06, 2020 example procedure for flushing an actual 3 floor office building. The basics of high velocity oil flushing clark reliance. During the flushing or the blowing of a line, some particles such as sand, rust, etc. In case this requirement cant be fulfilled the pipeline shall be reamed completely and flushed with water fulfilling the above requirement of 50 ppm max of chlorides. Often times significant amounts of piping, hoses, temporary pumps, and filters are required to perform a single flush. The biggest disadvantage to high velocity flushing is the complicated rig inout.
Water main flushing faq for consumers what is water main flushing. Run the water for 15 minutes for a 40gallon tank or 30 minutes for an 80gallon tank. The flushing discharge can also be calculated from the flow test data by using the formula provided in section 4. Open the clean water feed to the system or temporary feed if applicable slowly open the drain valves at the lowest. Turn on the hot water faucet at the kitchen sink to begin to flush hot water pipes. Consider protecting the devices within its network while performing cleaning. Compare the residual pressure during subsequent flushing operations to the water supply graph to estimate the water flow. The installer shall prepare and submit a method statement for agreement with the royal holloway university of london prior to commencing flushing.
Contractor shall remove all strainer screens prior to flushing all systems, including mud from the dirt legs. After flushing out and circulation operations with water have been completed, water shall be thoroughly drained from the unit. This process prohibits highly chlorinated water use in highrate flushing as most dechlorination equipment is not designed to accommodate such flows at such high levels of chlorine. The discharge rate was calculated using an equivalent pipe diameter of 26 to. Fill the system with clean water and drain the water after 30 minutes. In used systems, the emphasis is on the removal of contaminants that are generated during. It is the responsibility of the contractor to remove the flushing water or the chlorinated water from the project area. While completing cold water flushing, try to refrain from using water at other fixtures such as turning on other taps during the flushing procedure, as you may introduce particles into your piping. Contractor shall clean and replacereinstall all strainer screens after the final cleaning and flushing procedure has passed the final test criteria noted. Based on the results of the lab tests, the wt sp will give a verbal approval followed by a written approval for use or will give a verbal disapproval which requires rechlorination of the water system. Hydrostatic testing shall be performed using clam potable water with a chloride content of max 50 ppm for austenitic steels. Cfw when flushing is complete and approved water chemistry is achieved.
The basics of high velocity oil flushing by john bonner, director of field services, oil filtration systems high velocity oil flushing hvof is performed to remove contaminants from the piping and tubing of critical hydraulic and lube oil systems. Dewatering water is a problem that is often encountered in trenching operations. A water main is flushed with water to clean the pipe of surface dirt and other debris in the pipe. All parts of the drinking water system in contact with drinking water which are.
Oct 07, 2016 this method of flushing is easy to conduct by maintenance and operations crews, but requires a large amount of water and may not completely clean the pipe network. The flushing pump is located on the jackup boat, and a hose connects the pump to the pipeline via a hose that runs across the gangway. Inspection checklist pipeline inspection procedures contd code requirements code section reqd page 2 of 3 112011 s. Flushing of the water mains is done initially to remove any debris or dirt left in the pipe after installation. Each public water system should flush the water distribution system as necessary to reduce stagnant water and sediment buildup. Refill the system with clean water and run the chilled water pump for 2 hours. Wash hands and remove aerators to remove any particles from screens. Procedure for cleaning and flushing of the chilled water. When flushing is completed, dewater the system and dry as soon as possible. This should ensure all hot water currently in the hot water tank has been flushed and it will allow for fresh water to be heated.