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  1. What If CFD Modelling Was Readily Available For Residential Duct Design

    What If CFD Modelling Was Readily Available For Residential Duct Design?

    Author: Sam Myers

    Abstract

    Within the confines of the HVAC field, airflow behavior is one aspect that can be difficult to understand when it comes to proper duct system design and airflow measurement. The challenge of providing a visual display of an issue that is invisible to the naked eye is a regularity we face when working with clients, apprentices and students. Once a duct system is installed, we can use diagnostic tools such as flow hoods and duct testers to measure and expose air flow and leakage, then record our reading. We can also use thermal imaging equipment and smoke generators to make air behaviors visible. However, these actions are more reactive than proactive. What if we could see how air is supposed to behave inside our duct system during the design phase? Or show what happens if mistakes are made? The use of computational fluid dynamics (CFD) modeling can allow

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  2. Residential Duct Testing Now A Code Requirement in Virginia

    Starting in September of 2019, a duct leakage test will be required for all residential new construction homes that have ductwork outside of the conditioned space. This includes ducts located in vented crawlspaces, ventilated attics, and attached storage rooms that are not conditioned.

    In many states, a certification of some type is typically required. However, in Virginia’s case, the tester’s ability to operate the equipment is to be determined by the AHJ (Authority Having Jurisdiction).

    Luckily, Retrotec’s DucTester systems come with an online training module that provides the user with a Manufacturer’s Certification. This can be presented to building inspectors to provide proof that the tester is knowledgeable when it comes to testing ducts for leakage. This is unique only to the Retrotec brand of testing equipment.

    A recent Retrotec webinar, “Duct Testing Best Practices,” walks through duct testing pro

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  3. Danger Zone

    This is the 3rd installment of a monthly column from Ben Walker, Co-CEO of Retrotec. Ben's column focuses on observations on the art and science of high-performance building and home testing. 

    As many as 30 million U.S. homes may have loose-fill attic insulation made from asbestos-contaminated Zonolite. Here's how to determine if a home has it and what to do if it does.

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  4. Blower Door Testing in 1915?

    This is the 2nd installment of a monthly column from Ben Walker, Co-CEO of Retrotec. Ben's column focuses on observations on the art and science of high-performance building and home testing. 

    A blower door test, along with before and after load calculations of a leaky 1915 home, show the value of these technologies for remodelers and homeowners.

    A lot has been written about making new homes energy efficient, comfortable and healthy. That's important, but as more communities with high-performance new homes become available, more owners of existing homes want the same benefits.

    Just tightening up a home isn't enough, however. Homeowners want you to quantify the improvements. That's where testing earns its keep.

    Weatherization contractors and remodelers who specialize in energy retrofits talk about "testing

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  5. Let's Talk Tubing: Pressurizing a Building with a Blower Door

    Author: Sam Myers, Retrotec

    When pressurizing a building with a blower door, did you know that extra tubing must be added to the Channel B side of your gauge if you are not using a Retrotec DM32? If this tubing connection is neglected, you will have a reading that is approximately 20% high due to the open Channel B port that is referencing the indoor pressure of 50Pa instead of the outdoor pressure. Therefore, the extra tube is needed to connect that port on Channel B to the outside so that it is referencing the outside instead of the pressure induced by the blower door.

    However, the Retrotec DM32 automatically

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  6. Quality of the Highest Standard: Here’s What That Really Means

    Building and HVAC performance testers around the world rely on calibrated fans and pressure gauges to determine the construction quality of building envelopes, duct systems, and other building components. These tools include blower doors and duct testers which have been used for decades to measure the air tightness of certain assemblies. For these tools to become and remain accurate, they must be calibrated by the manufacturer once they are built and re-calibrated after a certain period specified by the manufacture. With Retrotec tools, this is every five years for gauges and fans.

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  7. Air Tightness Testing Comes of Age

    Blower doors and duct testers have become important tools for high-performance builders. A longtime industry veteran looks a how we got here and what's next

    This is the first of what will be a monthly column with my observations on the art and science of high-performance building and home testing. In this first column, I want to introduce myself and help you understand why you should care about these topics

    My name is Ben Walker and since May of 2017, I've been co-CEO of Retrotec, the world's largest manufacturer of blower door and duct testing equipment. Our products help designers and builders reduce building energy use, which contributes to a cleaner, healthier environment. That contribution is what gets me up every day.

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  8. Commercial Building Enclosure Testing

    Authored By: Sam Myers

    As building codes and owner expectations evolve, more commercial buildings across the United States are being designed to meet standards that reduce air leakage through the building enclosure. Some states are adding air tightness and testing requires to their building codes. There are also several third-party standards that require tighter building enclosures such as LEED and the Army Corps of Engineers.  The presence of a tighter building enclosure allows for lower utility bills, provides the ability to size mechanicals correctly, improves indoor air quality and reduces issues due to moisture brought in by outside air. According to the Building Envelope Technology Access Centre in Canada, most warranty callbacks for commercial new construction are due to moisture. These issues include shrinkage (nail pops and cracked concrete), water intrusion from poor grading, cracks and bad flashing details, interior finish damage from stains and joint movement,

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  9. Duct Testing Best Practices

    Authored By: Sam Myers

    Testing ductwork in residential HVAC systems for air tightness is essential to ensure a home will be energy efficient and comfortable. Tighter ducts help homes perform better by allowing conditioned air to travel to its intended destination. They also keep newly conditioned air from escaping to the outside of the home. More states and municipal code jurisdictions are including duct sealing and testing requirements in their energy codes for residential new construction. It is also a part of the RESNET HERS Rating process as well as a function of BPI Analysts when they perform energy audits. There are two methods used for testing ducts: Total duct leakage and leakage to outside (LTO). It is best to verify with local code requirements to see which method is specified. Some state and local codes specify a target for both methods. Both methods require the use of a calibrated duct testing fan combined with a pressure and flow gauge such as the Retrotec

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  10. Stay Safe Long after the Storm - Steps to Make Sure your House is Healthy after Hurricane Florence

    By: Sam Myers, Retrotec and Kristi Brodd, Advanced Energy

    Hurricane Florence brought record amounts of rainfall and devastating flooding across North Carolina, especially in the eastern part of the state. According to CNN measurements, some cities saw close to 3 feet of rain over four days, which is the highest rainfall total for any tropical system to hit the East Coast of the United States.

    As flooding recedes, many people are returning to their homes and beginning the restoration process. If you are moving back into a home that was flooded, it is extremely important to become knowledgeable on moisture management and take the necessary steps to keep your house safe and healthy for you and your family. Just because the water is gone and your house looks back to normal, does not mean that there is no damage or dangerous mold behind the walls, floors and ceiling.

    Many families suffered the effects of mold after flooding caused by Hurricane Floyd in 1999. Some

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