04/12/2019 In Services Technical

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Much time, effort, and care have been expended installing a water line. Crews have worked through inclement atmospheric condition. Unexpected rock was found, which slowed progress but did not terminate installation of the pipe. Crews have worked long hours to see deadlines and are anticipating the end of the project.

But wait, you have not pressurized the line. All eyes are on that guess in hopes of validating the work was successfully completed.

The blueprint engineer and owner anticipate news of a tight line, set up to serve hundreds or thousands of customers, or provide water to a new facility where a multitude of neighbors may find employment.

The following blog is a blue print, which, if followed, will lead to a successful hydrostatic testing of a h2o line using ductile iron piping. The aforementioned bones principles tin can exist practical to virtually other materials equally well.

Design

Hydro testing a new water line essentially begins during the design phase. Agreement testing factors during design will enable the water professional to prepare for obstacles that may arise during the testing procedure.

Exam requirements are ready by considering the post-obit:

  • Flow/volume demands
  • Size and length of pipe
  • Full overall difference from the low to highest elevations
  • Changes in elevation or "high spots."

The hydrostatic test parameters must exist clearly defined during the design phase and stated in the project specifications. Guidelines prepare forth in the AWWA M41 Manual and the ANSI/AWWA C600 Standard are every bit follows:

"Test pressure shall be 1.25 times the operating pressure. Duration of the exam is two hours. Special consideration must also be given when multiple pipage products are used."

A test pressure level of 300 psi will be detrimental to weak materials, such equally polyvinyl chloride (PVC) rated at 125 psi, which also does non take a safety cistron of ii and surge assart of 100 psi included in the design, compared to the stronger ductile iron that does.

Whatever material not designed for the specific pressures should not be used and should be isolated from whatever section of a line to be tested at higher pressures.

Jerry Regula conducts a hydrostatic exam on ductile iron pipe

Instruction

Complimentary on-site training services are provided upon request by McWane Ductile production engineers or sales representatives to ensure installation crews are empowered with the knowledge to complete the procedure. Engineering professionals frequently include on-site training past the manufacturer in the project specification to ensure training is completed.

There is also a benefit to documented standards compared to give-and-take-of-mouth training. How many times in your life accept you encountered a state of affairs such as this ane: A newlywed wants to cook Thanksgiving dinner. Her husband does not understand why she is cooking a 5-pound turkey in a 10-pound pot. The bride responds, "That'due south the way mom did it." The husband so asks his favorite female parent-in-law the same question and receives the same response, "That's the mode my mom did it." The married man then presents the question to grandma. Her response, "That was the only pot I had!"

Nosotros may chuckle a piddling, merely this happens all too oft in the field. There is a better solution, which is to base training from documented resources such as the AWWA M41 Manual or the ANSI/AWWA C600 Installation Guide for Ductile-Iron Mains and Their Appurtenances.

Installation

Attention to detail is of the utmost importance:

  • Cleaning the bells, spigots, and gaskets
  • Proper lubrication of gaskets and spigots
  • Use of approved accessories
  • Mechanical Joint installation should include gasket lubrication, straight alignment, and specified bolt torque
  • Proper alignment of joints during the homing process - "Directly is great!"
  • Deflection of joints -after the piping is homed

Anyone who has searched for a leak volition attest to the importance of proper installation. At that place is an extremely good chance that the about mutual installation, regardless of the pipe cloth, is improper tightening/torque of MJ bolts.

Hydrostatic Testing

ANSI/AWWA C600 Installation Guide for Ductile-Iron Mains and Their Appurtenances.

Warning: The testing methods described in this section are for water-pressure testing only. These procedures should not exist applied for air-pressure testing because of the serious safety hazards involved with compressed air. Too, pipelines intended for cached service should generally be tested with the backfill in place.

Steps to Follow

  1. Slow fill up the line. This will raise the probability of removing aII air from the conduit.
  2. Fill the line at the lowest possible location while providing an air release at the highest location. Multiple air release locations may be provided due to the contour of the line.
  3. Practice patience. Allowing all the air to vent and adequate time for any water assimilation in the cement lining are beneficial.
  4. The examination pump is to be connected at the lowest betoken of the line.
  5. Prime number the pump to remove all air prior to engagement with the line.
  6. The pressure level gauge is to be connected to the pipage at the lowest location. *Reminder - connect the gauge to the pipe, not the pump.
  7. The pump should be isolated from the line during the actual exam period.
  8. All head pressure will thus be included in the reading on the gauge.
  9. It is important to isolate the new line for pressure testing as well as allowing the new line to be properly chlorinated and leaner tested prior to connection with a service line.

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Allow for Movement

A water line moves like an accordion when pressures are increased/decreased. The trench type specified for the project is intended to residue the external forces involved simply will not eliminate move. Therefore, the number of times a line is exercised may vary. Installers may, at times, have a misconception that water lines practise non motility because of world loads of six to eight feet, for example.

Water Temperature

Water temperature is non typically a huge factor during hydrostatic testing but must be considered at times. Internal pressure will decrease equally water temperatures decrease-to the point when the fluid begins to freeze, which then creates a substantial issue.

Alternatively, pressure will rising every bit h2o temperature increases. If a h2o line installed in the winter is filled with city h2o at lx degrees Fahrenheit and the ground temperature is 32 degrees Fahrenheit, the water volition cool and the pressure will drop.

Conversely, the internal force per unit area may increase for an in a higher place-footing line installed during summer months filled with sixty degrees Fahrenheit h2o and ambience temperature of 90 degrees. This is specially truthful if the line is exposed to direct sunlight.

Measuring water for a hydrostatic test.

Pressure Versus Make-Up

A mutual error is for installers to chase a leak for extended periods of time, but to find the line will somewhen pass the hydrostatic test without changing whatever parts of the water line. Considering the commanded make-up h2o may alleviate this issue.

Tabular array iv-A found in section 5 of the ANSI/AWWA C600 Standard is used to identify the corporeality of make-up water used (per hour) to increase the pressure back to the starting indicate of the test. The same information may also be obtained in seconds via the McWane Ductile Pocket Engineer.

McWane Ductile Tools

The Mc Wane Ductile Double Bump protocol is an excellent diagnostic procedure written for operators to differentiate a leak from trapped air:

  1. Three hydro tests are conducted with each having the same time intervals.
  2. The pressure is increased during each test.
  3. The brand-upwardly water is measured and documented afterwards each test.
  4. Ensure the pump is primed before the valve is opened to the water line.
  5. The water supply container must exist marked at the h2o level to assist with calculating the make-up water.
  6. A "known value" container such as a quart jar or incremented gallon bucket may be used to refill the original supply source.
  7. The amount of brand-up water is documented and compared from all three tests.

RESULTS:

If the amount of make-upwards h2o remains the aforementioned or slightly improves, this is an indicates trapped air. A substantial increase in the amount of make-up water as the force per unit area is increased indicates a leak is nowadays.

Testing With Air

Let'south be perfectly clear: An air test is absolutely non the same as a hydro test. Note the statement from the ANSI/AWWA C600 Installation Guide for Ductile-Iron Mains and Their Goods:

Hydrostatic Testing

WARNING: The testing methods described in this section are for h2o-force per unit area testing simply. These procedures should not be applied for air-pressure testing because of the serious prophylactic hazards involved with compressed air. Too, pipelines intended for buried service should more often than not be tested with the backfill in identify.

Nosotros recommend using hydrostatic test procedures for all water lines if possible. The dangers of compressed air cannot exist over emphasized.

Recollect nearly it, you lot have installed a h2o line - examination with water. If, as a last resort, testing with air is the but option, there are items of concern:

  • Two to four psi is all that is required for an air test.
  • The punch on the gauge must be in one psi increments.
  • A force per unit area relief valve is to exist set at five psi max to prevent over pressurizing.

An example to compare h2o and air: fill one balloon with water and the second with air. Popular both balloons. The water balloon will but autumn to the basis while pieces from the air balloon may travel several feet when popped.

Yes, a ductile atomic number 26 cap is heavier than a balloon, which ultimately means it will do more than damage when information technology lands. Work smart, work hard, and work safe!

Conclusion

There is a cracking deal of idea, preparation, and attention to detail involved with hydrostatic testing. Keep in mind there are documented procedures and knowledgeable McWane Ductile staff available for assist. Frompattern to installation, we take great pride in providing education and training to water professionals throughout the water and waste h2o industry. Together, we are Building Iron Stiff Utilities for Generations!

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Jerry Regula, ENV SP, NACE CT

Jerry Regula, "JR" is a product engineer with McWane Ductile. Jerry'due south responsibility is to provide technical support for water professionals at all levels including engineers, private water companies, contractors, municipalities, and h2o districts. JR has been with McWane Ductile for more than xxx years, starting on the ground floor. Jerry has been involved in nearly all facets of the foundry, providing him with extensive experience in manufacturing, installation, and design of ductile iron water products. JR is a NACE Certified Corrosion Technician, Envision Specialist, and fellow member of the American Society of Civil Engineers. He enjoys spending time with his church where he is a speaker and treasurer, too equally spending fourth dimension with his wife Susan and their two daughters, Katelyn and Shannon on their farm in Ohio. "Many people do not realize how their h2o gets to them or how blest we are to take clean drinking water," says Regula. "I am honored as a water professional to do my part in 'Building Atomic number 26 Strong Utilities for Generations.'" Jerry's favorite quote: "I can exercise all things through Christ who strengthens me." jerry.regula@mcwaneductile.comhttps://world wide web.linkedin.com/in/jerry-regula-6a87b8138/