KAVERI INFRASTRUCTURE

KAVERI INFRASTRUCTURE PVT LTD

Projects Executed

 

Services

 

Machinery & Infrastructure

 
 

REHABILITATION OF WATER MAINS

 

SPRAY LINING

 

Keeping the further development we thought of lining of Water pipes, which is a major requirement for the development of urban system as it provide a great amount of saving of drinking water as Water is life. Looking at the requirement of this technology we had made an MOU with Pipeway,U.K. who are leaders in this field. In this field we have sourced out the development and maintenance of the water supply system. This is a Trench less renovation of Water Rising Mains through Spray Epoxy Resin and Rapid setting Polymeric Lining Systems. This most effective in bent pipes of large diameters ranging from 900mm to 1500mm. It also provides minimal disruption to public and their activities. This covers approximately 250 mtrs in one stretch within 24 hours so that water supply is not disturbed for a long time.

 

Spray Lining of Water Rising Mains by Epoxy Resin and Rapid Setting Polymeric Resin

  

 

Often with water pipelines the principal objective is to remove scale and corrosion, and then apply a coating which will inhibit further deterioration and may seal very minor leaks. The most common materials used for this purpose are cement mortar or epoxy resin, applied by a robotic spraying machine which is winched through the pipe at a constant, predetermined rate.

  

 

1)    SEQUENCE OF WORKS:

 

a)   Excavation of Pits

b)   De-Watering

c)   Cutting and Dismantling of Pipe

d)   Cleaning (Removal of Scale)

e)   Pre-Lining CCTV Survey

f)    Spray-Lining

g)   Post-Lining CCTV Survey

h)   Commissioning of Water Lines

 

a)    Excavation of Pits: - JCB will be used to excavate the soil which will be immediately loaded to a truck to store it in the site office premises. The stored soil will be used to re-fill the pit.

 

b)   De-Watering: - Proper shut down of the water mains have to be done before commencing work.

 

While the Cutting process will be in progress pumps will be lowered into the access pits simultaneously.

 

By the time the cutting process is complete a lot of water will already be dispersed because shut down of the supply would have been done 5 hrs prior to that.

 

The remaining water in the pit will be emptied by submersible pumps to the nearby nallah or stored in the tankers to be disposed into the nallah.

 

c)    Cutting and Dismantling of Pipe: - Proper shut down of the water mains have to be done before commencing work.

 

In case of CI mains, 12mm to 15mm of the total thickness of 35mm will be left grinded the night before.

 

After shutdown has been activated, grinding will start simultaneously at the pits. Two sets of grinders will start working together per pit. It is mandatory for the persons working to wear all PPEs and take punitive safety measures.

The CI mains will be cut till 5mm thickness is left at 2M interval at two places. A zig-zag cut will be done 25cm away from any of the cuts. Then using hammer the 2M piece of CI mains will be dismantled and towed away above the pit using Hydra.

In case of PSC mains, simple 5kg hammers. 5 persons per pit will be engaged in this work. Hexo-Cutters will also be employed for cutting reinforcements along with LPG and O2 cutters. Work will start simultaneously at 3 places.

The dismantled materials will be towed away and loaded on open dumpers to be taken to site office.

 

d)   Cleaning (Removal of Scale)

 

A  number  of  cleaning  techniques  are  suitable  for  the  removal  of  debris  and encrustation so as to prepare the main for lining. These include:

•              Power Boring (diameter range 75mm to 250mm illustrated below);

 

•              Drag Scraping (diameter range 75mm to 1025mm);

 

•              Abrasive Pigging (diameter range 75mm to 300mm);

 

•              Pressure Scraping (diameter ≥ 300mm);

 

•              Pressure jetting (all diameters).

Plunging can be used to remove residual corrosion debris and water from the pipe.

 

 

 

    Figure 1 Power Boring

 

 

Preparation of Cleaned Mains

 

Prior to spray application of any resin lining material, the main shall be free from standing water. This is achieved by foam swabbing (using oversized clean swabs) and applies to all mains diameters of 75mm and above.

Swabbing is used to remove residual corrosion debris and standing water from the pipeline.

 

 

    Figure 2 Foam swabbing

 

e)    Pre Lining CCTV Inspection/Post Cure CCTV Inspection: - Using High Pressure Water Jetting and/or Drag Scraping, through the specified water line and removing all accumulated debris to facilitate the CCTV survey. At the end of each shift check that all pits are secure and site left safe and tidy. All works to be monitored by CCTV, and a video recording made on completion.

 

All works within confined spaces shall be carried out in accordance with HSE Guidance note GS5 “Entry into Confined Spaces” and KIPL working manual.

 

 

   Figure 3 CCTV inspection

 

 

 

   Figure 4 Spray lining application

 

f) Spray lining: - The lining is applied using a centrifugal spraying machine similar to that used in cement mortar lining. The resin and hardener components, which are manufactured in different colors to aid the checking of mix efficiency, are fed separately to the lining machine in the proper ratios by means of a multi-cylinder positive displacement piston pump. The epoxy components are mixed in a static-mixing chamber located at the rear of the machine. As with cement mortar lining, a surface-mounted winch pulls the lining machine at the constant speed that will deposit the desired 1 mm to 2 mm lining thickness.

The lining is allowed to cure to a tack-free state before the main is reconnected and water is reintroduced. Curing takes approximately 3–4 minutes, depending on ambient temperatures.

 

The main is charged with water chlorinated to 50 mg/L free chlorine and is allowed to stand for 30 minutes.

g)   Commissioning of Water Mains: - The main is flushed for 1 hour after de-chlorination and is then returned to service.

 

n  Spray lining techniques for man-entry pipes and chambers include Renovation of Large Diameter Pipes and Chambers Section.

n  Often with water pipelines the principal objective is to remove scale and corrosion, and then apply a coating which will inhibit further deterioration and seal very minor leaks.

n  The most common materials used for this purpose are cement mortar or epoxy resin, applied by a robotic spraying machine which is winched through the pipe at a constant, predetermined rate.

n  The aim is usually to increase the pipe’s resistance to external loading rather than to prevent corrosion, and partly because of the practical difficulties of ensuring that inflow to the sewer is completely stopped while the material is being applied and cured.

n  A practical spray-lining system for sewers would avoid the problem of lateral reconnection inherent with most other renovation techniques.

n  Spray lining is seldom used in gas.

n  Spray lining is usually intended as a protective coating relying on a bond with the existing substrate.

n  Old water mains, particularly those made of cast iron, often have heavy internal deposits of corrosion and scale, which in some cases may reduce the effective bore to a fraction of the original size.

n  Cleaning techniques include high-pressure water jetting, scraping, pigging, rack-feed borers and mechanically-driven devices such as cutters and chain flails.

n   Pipe scrapers are designed to remove hard deposits and nodules when winched through a pipe, and consist of a number of spring steel blades mounted on a central shaft.

n   A towing eye is fitted to each end of the shaft, allowing the tool to be pulled back if necessary.

n  Wire brush pigs comprise two circular wire brushes on a central shaft with a towing eye at each end, and are used to remove loose deposits and dust prior to lining. They may also be used to remove debris loosened by a pipe scraper.

n  Deposits are normally driven through the main by water pressure, and can travel distances of several kilometers in continuous pipelines. In a heavily encrusted pipe, pigging is carried out in stages using pigs of increasing size.

 

Non-Structural Lining for Potable Water Mains
 

Our supplier for the resin, E.Wood Ltd through its Copon brand name has for many years been at the forefront of the development of protective products for pipes carrying potable water within the international water industry. The resin is manufactured under the brand name Copon Hycote, U.K.


Copon 169 is a two part urethane system, light grey in colour with a similar, but glossier, appearance to epoxy resin coatings when cured.
This product is called Copon Hycote 169. The rapid setting characteristics of the Copon Hycote 169  ( curing fully in 1 minute after application)  means that water mains can be put back into service with the minimum of delay and without undue disturbance to the water company's customers.
Ratio of mixture of epoxy resin = Base : Activator = 1 : 2.5


The product is a true no dig technology meaning that the number of excavations required to install the product are minimal, and traffic management requirements are considerably reduced. The speed of application of Copon Hycote 169 and the lack of associated disruption during installation has meant that Copon Hycote 169 will continue to be the product of choice for non- structural potable water pipeline rehabilitation.
 

After mixture and application of pipewalls, initial set is achieved in appx. 40 seconds with the coating hard and unmarkable after appx. 2 minutes. With such physical properties it allows for CCTV inspection to be undertaken within 10 minutes of lining.  A cure period of 30 minutes is required from completion of lining to commencement of return to service procedures. These comprise, as with epoxy resin lining, a 30 min. chlorination contact time, followed by one hour of flushing.

 

Fully approved by Drinking Water Inspectorate (DWI) & National Science Foundation (NSF) for application to potable water systems. DWI is responsible for assessing the quality of drinking water in England and Wales, taking enforcement action if standards are not being met, and appropriate action when water is unfit for human consumption.
 

A spray lining product is a cost effective alternative to slip lining and pipe bursting techniques. This unique system enables a non-structural internal lining to be installed and allows the pipe to be returned to service in the same day!.


Benefits of the System:

  • Same day return to service
  • High abrasion resistance
  • Restores hydraulic capacity
  • Enhances original pipe structure
  • Corrosion void spanning capability
  • Does not block service connections
  • Can eliminate water loss within a problematic pipeline by sealing joints

 

 

© Copyright KAVERI INFRASTRUCTURE PVT. LTD. All Rights Reserved.

Design by: PGPS Web Solutions