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Easy, Accurate Way to Optimize Radon Fan and Pipe Size Selection
Reading time: 4 minutes
Safety
New Technology Provides an Easier, More Accurate Way to Optimize Radon Mitigation Systems
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When it comes to radon testing and mitigation, “innovation” isn’t always the first thing that comes to mind. Many radon mitigators rely on the “poke and hope” method of sub-slab depressurization without performing pressure field extension testing. The persistent complexity of testing methods discourages many mitigators from adhering to recommended protocols.
A new Pressure Field Extension Diagnostic Kit (PFEDK) could be the answer, providing an easier, accurate way to optimize fan and pipe size selection for more reliable and efficient outcomes.
The Diagnostics Challenge
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The end goal of most radon mitigation is straightforward—create a negative pressure in the soil beneath the slab. Pipe size is often crucial to the efficiency and effectiveness of a sub-slab depressurization system, but size selection is mostly guessed at or installers simply utilize the same fan and piping out of habit. This can lead to over- or undersized pipes. If negative pressure under the slab is not generated or if too much is generated, the mitigator will have to return to the jobsite to install another suction or a larger fan or the homeowner will be saddled with a decade or more of unnecessarily high energy costs and noise levels due to an oversized fan.
A lot of mitigators don’t think about the energy penalty associated with installing an oversized fan—and the fact that the fan can actually be pulling conditioned air out of the house.
Certified radon mitigation and measurement specialist and Lead Radon Mitigation Trainer for Kansas State Engineering Extension
To avoid these issues, radon mitigation system pipe sizing can be determined easily by good pressure field extension testing. In the past, however, mitigators have avoided the process because it was deemed too complicated and time consuming. It required a depth of understanding and a certain amount of engineering expertise, as well as an assortment of tools, including a pitot tube and a micro-manometer, that they often did not have.
In fact, Robinson estimates that as few as 10% of radon mitigators practice proper diagnostics. Proper diagnostics have been a time-consuming, multi-step process that is poorly understood by many practicing radon mitigators. And without any enforceable guidelines, there’s little incentive to learn. Mitigators commonly assume a job is done when a fan gets a home below 4 pCi/L continuously for a 48-hour test.
A New Approach to PFE Diagnostics
The PFEDK is a simple-to-use tool that any radon mitigation expert or installer can learn to use quickly. The Kit comes with a simple-to-use online application that facilitates fan selection and pipe sizing by accurately determining sub-slab pressure characteristics and calculating PVC pipe pressure drop (loss). The testing can easily be part of an actual radon mitigation installation or performed before a system is installed.
Here's how it works:
Each kit includes a variable speed electronically commutated motor (ECM) fan, pressure-sensing couplings to fit a 4-inch PVC pipe, digital manometer, and cross reference materials, all packaged in a heavy duty rolling case.
After the installer selects the best location for the slab penetration and a sensible routing course for the pipe, he or she seals a small section of PVC into a suction pit that has been thoroughly excavated and installs the ECM fan and couplers. A flexible duct is recommended to safely exhaust radon and dust from the working environment during the diagnostic process.
The installer drills several small test holes into the slab (as far away from the suction pit as possible) for evaluating the pressure field extension. The installer will use the manometer and pressure tubes to measure the pressure differential across the fan at maximum fan RPM, making note of this first reading.
To ensure good communication between the suction point and other test holes, the installer will go to each slab test location and use a micromanometer to make sure the full footprint of the slab is under sufficient negative pressure to overcome any house pressure that may be generated by stack effect pressures, exhaust fans, or operation of the HVAC system.
The installer gradually lowers the RPM of the fan, systematically rechecking the test holes to make sure a sufficient pressure differential is maintained at all test points. The installer then checks the number on the digital display on the fan electric box. This value, which will be between 0 and 10, is the voltage that controls the ECM fan RPM and represents fan speed.
At this point all the required data has been collected. The installer accesses the online application and enters the data collected from the PFEDK.
The app calculates the total system resistance, selects the best fan, and displays all suitable pipe diameters for the job.
For mitigators who already adhere to recommended diagnostic protocols, the PFEDK can be a major time saver. It also improves accuracy and helps mitigators differentiate themselves in the eyes of homeowners.
This tool has the potential to awaken pre-mitigation diagnostics that has been mostly non-existent
President of WPB Enterprises, the oldest radon mitigation company in Pennsylvania.
Like most mitigators, Tod Boss and his mitigation team at RadonProz, which services residential and commercial properties throughout northwest Ontario, Manitoba, and Saskatchewan, find that determining sub slab pressures and characteristics to be the most challenging part of the job, especially in areas of Manitoba where sub-soil conditions can be especially tricky to deal with. Since incorporating the PFEDK into their mitigation procedures the job has become a lot easier.
"We saw the value in this product immediately," says Tod. "The kit and the app have made it easy for our team to determine exact negative pressure and for our installers to size equipment appropriately the first time and avoid costly return trips."
In addition to providing faster, more exact diagnostics, Boss has also found that the system provides helpful data sharing and has improved their record keeping.
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An Easier Path to Saving Lives
Radon diagnostics and mitigation have had a painfully slow evolution. The PFEDK has the potential to accelerate the process and elevate mitigators to a more professional position in the minds of homeowners.
Like doctors, radon mitigators help save lives. Scientists estimate that lung cancer deaths could be reduced by 2%, or about 5,000 deaths, by lowering radon levels in homes. But doctors don’t diagnose patients without the help of technology and innovation. The PFEDK not only brings ease and accuracy to the science of radon mitigation, it builds credibility in the minds of homeowners.
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