Airfield location meant inspection scheduling was booked five months in advance.
Water main inspection to manage the critical assets for the Vancouver International Airport takes months of proactive planning, safety and scheduling.
In the management of a major international airport like Vancouver International Airport (YVR), Vancouver Airport Authority (VAA) operation officials inevitably face a number of unique challenges. Compounding the challenges is the fact that the airport runs as a mini-municipality because of its size and island location within the jurisdiction of the City of Richmond.
When carrying out a water main inspection in an airfield location, strict rules apply to how you operate in that area. A well-executed inspection requires a dedication to planning, safety, and scheduling.
“Being an airfield location, a lot of detailed planning went into managing this South Runway Watermain Inspection. We stuck to the schedule, met all milestones, and were extremely pleased with the execution of the safety plan, which was critical in this restricted environment.” Stephen Little, Technical Specialist-Mechanical, Vancouver International Airport.
The water line provides an important service to South Terminal and leased buildings.
Canada’s second busiest airport, YVR, served 24.2 million passengers in 2017. Last year, VAA engaged Pure Technologies to perform a Sahara® leak and air pocket detection inspection on the South Runway Watermain (SRW). Built in 1966, the SRW is a 350mm water main constructed of asbestos cement that runs from the Airport Field Bulk Water Meter to the South Domestic Terminal for approximately 870m (2850 ft.).
The water line provides an important service to both the South Terminal and leased airport buildings, which include a busy McDonald’s, the Floatplane Terminal, Flying Beaver Bar & Grill and multiple aircraft maintenance facilities. The line also runs along the main airfield, and across some taxiing areas, driving home the point that failure is not an option.
The airport receives water from the City of Richmond, which was also keenly interested in the inspection planning, technology and the outcome.
A multi-purpose inspection
The main purpose of the survey was to assess the condition of the main to identify and accurately locate any leaks or air pockets using the acoustic capabilities of the Sahara leak detection tool. VAA wanted a visual take on the inside of the pipe using the video capabilities of the tool’s CCTV camera. In addition, VAA also wanted to map the bends in the line and take GPS coordinates at select points to update alignment plans.
Another important purpose of the inspection was to eliminate water loss at the airport, a goal initiated by management as part of a proactive environmental program to conserve water. Management wanted to locate areas of potential water loss in their system to help achieve their water reduction targets of 30 percent by 2020.
YVR receives water from the City of Richmond via several bulk meter locations. From here, VAA distributes the water throughout Sea Island. The presence of leaks would have an adverse effect on the airport reaching its water reduction targets.
Tethered Sahara tool is propelled by the product flow and features inline video to observe internal pipe conditions.
Sahara leak detection platform selected
Pure recommended the Sahara leak detection platform for its ability to provide same-day results, and to locate small leaks with sub-meter accuracy. The tethered tool is propelled by a small parachute inflated by the product flow.
The Sahara platform also features inline video that allows operators to observe internal pipe conditions, and in many instances, identify the type of leak and other details helpful for planning a repair before excavating.
Although this first project was limited in scope and budget, because of the criticality of the line, both Pure and VAA put extra care and planning into efforts to ensure a relatively effortless access and retrieval of the condition assessment tool.
The City of Richmond assisted by removing their aging water meter and installing the flange supplied by the Sahara team for the launch of the tool. The City of Richmond then took the inspection opportunity to upgrade the old meter to a newer ultrasonic model.
Airfield location meant maintaining inspection schedule was critical
As the line was located in the airfield, maintaining the inspection schedule was critical. Security escorts were required at all times for non-YVR employees, which meant scheduling for the project was booked nearly five months in advance.
As well, the inspection was a multi-jurisdictional project, as the pipeline was owned by both the City of Richmond and VAA, requiring close collaboration between all parties. Pure inserted the tool via the City of Richmond’s water meter (in the airfield) and inspected the downstream water main (owned by VAA).
“The South Runway Watermain inspection project was a good opportunity to trial and gain better understanding of the inspection technology. It also allowed us to get a level of comfort in order to identify other areas where we can apply it,” said Little. “Our comfort how well the inspection went is an incentive for us to explore more non-destructive inspection methods.”
The adaptable design of the Sahara tool allowed for a horizontal insertion at the water meter chamber. (Vertical insertion is the more common method for inserting the tool.)
The adaptable design of the Sahara tool allowed for a horizontal insertion (vertical is more common insertion method) at the water meter chamber and the inspection was completed under live conditions without disruption to service, using the water meter bypass and downstream fire hydrants.
In a single day, the Sahara crew inserted the tethered tool through the water meter chamber, inspected approximately 870 meters (2850 feet) and determined the pipeline alignment with all bends and 100-meter intervals marked. In conjunction with the inspection, VAA and the City of Richmond were able to upgrade the old water meter to an ultrasonic unit, a bonus to the inspection goals.
In the end, zero (0) leaks and zero (0) air pockets were identified during the inspection, and CCTV showed some small tuberculation on the metallic bends. Although VAA recognized no immediate concerns, the Airport Authority now knows the correct updated line location and the overall condition of their assets.
Overall, a great success for a pilot project.
A leak represents not only water loss, but can indicate the potential for pipeline failure.
How proactive utilities are taking the gamble out of finding leaks in order to mitigate failure risk
It takes a lot more than luck and traditional acoustic correlation methods to locate a suspected leak on large critical mains. Not all leaks are obvious, and some leaks can seep for years without visibly surfacing, putting utilities at risk for catastrophic failure.
That is why a proactive leak detection strategy plays such an important role in any asset management program. It allows utilities to obtain the general condition of their mains, since a leak not only represents a real water loss, but can also indicate the potential for pipeline failure.
Recently two water operators — The City of Vancouver, B.C. and The City of Norman, Texas— took measures to mitigate failure risks by implementing a leak detection program for their transmission networks. The utilities deployed various inline leak detection technologies, dependent on such factors as pipe diameter, material, access point availability, and operational constraints.
Left: Acoustic intensity of anomaly. Right: Actual leak located
Inline technologies for leak detection
Inline leak detection technologies use non-destructive methods in which acoustic sensors are inserted into a pressurized pipeline. The “hissing” sound or vibration resulting from a leak in a pipe transmits an acoustic signal collected by the sensor when passing the leak site. The amplitude and frequency of the sound depends on the pipe material and internal pressure, and is easy to distinguish from other pipeline sounds.
Pure Technologies has developed two inline leak detection platforms for large-diameter pipelines of all materials: Sahara® (with a tethered sensor) and SmartBall® (a free-swimming tool). Both tools are equipped with a sensitive acoustic sensor that can locate very small leaks (as small as 0.1 l/min) with high location accuracy.
The SmartBall tool can be launched while the main remains in operation, limiting disruption to service.
SmartBall leak detection technology
The SmartBall platform is an innovative technique to identify leaks and gas pockets in large-diameter pipelines while the line remains in service, minimizing disruption. The free-swimming ball contains a sophisticated leak detection circuitry and is released untethered into the water flow often through an air valve or hydrant (any 100mm opening). The SmartBall follows the water flow and is tracked by surface mounted sensors as it rolls through the pipe making a continuous recording of the acoustic activity in the pipeline. At a downstream location, the ball rolls into the retrieval device and is extracted from the pipe. The data is then evaluated to report the presence of leaks and gas pockets.
Since the SmartBall is propelled by the water flow, it can be used to survey the subject main for long distances (battery life up to 20 hours) in one deployment. As a result, modifications to the main are significantly reduced.
The tethered Sahara platform provides acoustic data on the presences of leaks and gas pockets and has the ability to map the pipeline alignment.
Tethered Sahara inspection platform
Utilities have long relied on the Sahara leak detection platform for speed, accuracy and real-time results.
The tethered platform identifies leaks and gas pockets by providing acoustic data on the presence of leaks for distances up to 1,800 meters (6,000 feet). The tool also has the ability for mapping the pipeline alignment, and is equipped with CCTV, adding an assessment.
The tool can be inserted into an active pipeline, through almost any tap two (2) inches and greater. As the Sahara tool enters the pipe, the flow velocity of the water inflates a small parachute, which pulls the tool through the pipe, with the probe lighting the way, highlighting any visual defects in the pipeline.
If the Sahara tool encounters any acoustic events – such as a leak – the operator can stop the tool at the exact point of the leak. At the same time, an above ground operator locates the sensor, marking the exact leak location within plus or minus 0.5 meters (18 inches). This enables users to know in real time where leaks are located.
The SmartBall tool was successfully retrieved with the acoustic data intact.
City of Vancouver SmartBall inspection
In March 2016, the City of Vancouver retained the services of Pure Technologies to perform a condition assessment of the Powell-Clark Feeder Main. The pipeline is comprised of concrete cylinder pipe (PCCP/BWP), ranging from 750 to 900m in diameter, installed in 1986-87.
In addition to providing an earlier PipeDiver® electromagnetic inspection to identify broken prestressing wire wraps on the main, Pure Technologies also performed a SmartBall inspection to identify and locate leaks and pockets of trapped gas along the line.
The SmartBall tool was inserted into the pipeline through a flange access and acoustic data was collected and recorded as the tool traversed the pipeline. At a distance of 5.8 kilometers, (470 meters from the end of the inspection run), the tool stopped, which was confirmed by the live tracking software. By analyzing data from the earlier PipeDiver EM inspection, Pure determined that unknown debris likely lodged the SmartBall tool.
The City excavated and modified a tap to allow Pure to access the pipeline with a submersible ROV (equipped with a camera) to retrieve the SmartBall tool and examine the debris, which turned out to be an old tool cart. The cart and SmartBall tool were extracted, and the data considered valid.
Analysis indicated three (3) anomalies characteristic of leaks and zero (0) pockets of trapped gas. Two (2) instances of entrained air were identified as migratory acoustic anomalies, and flagged for future inspection, as they may develop new pockets of trapped air.
When combined with the results from the EM inspection, the condition data will be used as part of the City of Vancouver’s asset management initiative and allow for proactive measures in the management of their infrastructure.
Sahara inspection for City of Norman, Texas
In December 2016, Pure Technologies performed a leak detection survey on the 30-inch Robinson Street Replacement Water Main (RSRWM) for McKee Utility Contractors (McKee). The RSRWM is owned and operated by the City of Norman, Oklahoma.
McKee suspected a leak on the pipeline, as the RSRWM was failing to hold pressure during the 150 psi hydrostatic pressure test. As a result, McKee requested that Pure Technologies inspect 4,248 feet of the RSRWM and pinpoint any leaks in the inspected section.
The Sahara platform was selected for its ability to provide same-day results, and to accurately locate small leaks with sub-meter accuracy. The tethered tool is propelled by a small parachute inflated by the product flow, requiring a flow velocity as little as one foot per second to progress through a water main.
Because the pipeline was not yet in service, the flow was generated with a city connection pushing water into the main, and a 12-inch blow-off spewing it out. The Sahara audio-visual (AV) sensor was deployed to the endpoint using the flow velocity provided by the blow-off.
After the leak was located and marked above ground, McKee quickly excavated around the butterfly valve, tightened the bolts and eliminated the leak on the same day.
Two leaks detected, located and repaired
As a result of the survey, 4,294 feet of the RSRWM was inspected, with two leaks located.
Leak 1 was located 1000 feet from the first insertion. Video from the Sahara tool showed that the leak was located on the mechanical joint securing the inline butterfly valve to the pipeline. The Sahara team located the leak, and marked it above ground and McKee was able to start excavating immediately. After quickly excavating the butterfly valve, McKee was able to tighten the bolts on the BFV, eliminating the leak the same day as the excavation.
A second leak was located, marked above ground, excavated, and repaired the same way as the first. After repairing the two leaks found, the line passed pressure test.