The recent catastrophic collapse of a pipeline at a $10 million project in Central America is clear proof that current procurement of air valves needs to be urgently reviewed. Plus, this latest incident was actually caused by not having any air valves at all, which was a disastrous oversight by the consultant. However, in an increasing number of cases, it is not the end-user or the contractor at fault. Rather, it’s a lack of understanding from consultants who don’t seem to understand that when putting water into a pipeline or draining out due to a burst, air must be let in—and let out.
DANGERS OF NEGATIVE PRESSURE
The vacuum created by negative pressure in a system (caused by no air valves or the wrong type of air valves) is enough not just to destroy plastic pipelines, but tough metallic materials too. The misguided recommendation by the consultants for this project in Central America was to make do without Air Valves, which probably “saved” around £7,000. What an oversight—but it is far too common.
PENNY-WISE AND POUND-FOOLISH
In the United Kingdom, a plague of cheap plastic Air Valves in the ground can be found in myriad projects. These valves are a single, air-out only function, costing around £70 apiece. Instead, two-way valves (for air-in and air-out) should be installed, which would be the safer option. However, because they’re often twice the price (at closer to £170 each), procurement departments or consultants believe they’re doing a great job with savings. In the short-term, perhaps they are right, but they would need to explain why in the United States alone now $346 billion worth of failing assets are now in the ground. The evidence points to this not being much of a saving at all.
CUTTING CORNERS IS RISKY BUSINESS
Recently, when quoting on one recent project, an asset manager had to admit that although the municipal company knew they had air valves, they didn’t know exactly where—only that the contractor had used “a load” left over from a previous job. Subsequent failures with poor tap pressures was already producing numerous complaints from consumers, giving the water company concerned some very unwanted SIM points.
In an age where anyone could use Google to get an idea of topography, it seems unforgiveable that some consultants aren’t even specifying air valves to be installed every 1,500 feet on just a straight length of pipe. And it’s madness too for those who do specify to then cut corners with cheap or unsuitable air valves. It is time to install the right, long-lasting product and stop adding to the stockpile of failed assets buried in the ground.
About the Author:
Craig Stanners is the director at IVL Flow Control, part of Ham Baker Group, and can be reached 07772.699313 or craigstanners@ivlflowcontrol.co.uk. IVL Flow Control provides solutions for a range of water utilities and industrial markets. For more information, visit www.ivlflowcontrol.co.uk
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MODERN PUMPING TODAY, May 2016
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Pipeline Collapse Shows Urgent Need for Two-Way Air Valves
