Standard 310 is a technical workflow created by ACCA, ResNet, and ANSI for grading the installation of HVAC systems, typically in new home construction. It plays a crucial role in obtaining Energy Star certification, which can qualify homeowners for tax credits under the Inflation Reduction Act. The five steps of Standard 310 are design review, duct leakage test, total system airflow, blower fan watt draw, and refrigerant charge verification.

In this podcast episode, host Bryan Orr is joined by guests Chris Hughes and Eric Kaiser to discuss Standard 310 and its implications for HVAC contractors.

The standard aims to ensure that HVAC systems are installed correctly and operate as designed. The process involves a third-party HERS rater conducting various tests and measurements, which contractors need to be prepared for. Proper duct sealing, airflow settings, and refrigerant charging are critical for passing the assessments.

One of the challenging aspects highlighted is the refrigerant charge verification step. The standard requires either non-invasive testing (which has temperature limitations) or weigh-in verification with geotagged photos. Chris Hughes suggests manufacturers could develop more consistent commissioning protocols to streamline this process.

Topics covered in the podcast:

• Overview of Standard 310 and its five steps
• Importance for Energy Star certification and tax credits
• Role of HERS raters and HVAC contractors
• Duct leakage testing and proper sealing
• Airflow measurement methods
• Blower fan watt draw challenges
• Refrigerant charge verification options
• Need for consistent commissioning protocols
• Coordination and documentation required
• Future improvements to the standard

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In this short Q&A podcast episode, Bryan answers Gunther's question about kitchen exhaust and makeup air. Gunther asked if there were any studies that showed that makeup air should come very close to the hood to avoid infiltration. He also asked how to educate others who push back against the idea, particularly in kitchen exhaust systems of around 600 CFM.

Commercial facilities, especially restaurants, bring in makeup air to balance out the air being exhausted. There are costs associated with makeup air, but there are plenty of valid reasons to add it to residential structures. Being able to control the makeup air allows us to control where we bring air in from (especially when it comes to drawing in humid air or dirty attic air from gaps and cracks, particularly in vented attics).

Open-combustion appliances in the building envelope are also prone to backdrafting if the structure is under negative pressure. The structure is also more likely to have its dryer vents experience leaks under negative pressure.

The International Residential Code (IRC) (section M1503.6.2) requires makeup air when you have an exhaust system >400 CFM. The Florida Residential Code (section M1503.4) requires kitchen exhaust systems exceeding 400 CFM to have makeup air at approximately the same rate as the exhaust rate. Furthermore, the Florida Mechanical Code (section 505.2) specifies that kitchen exhaust systems exceeding 400 CFM must have makeup air to balance the air pressure and ensure proper ventilation.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Purchase your virtual tickets for the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

Subscribe to our podcast on your iPhone or Android.

Subscribe to our YouTube channel.

Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

This episode featured Bryan Orr interviewing Sam Myers, the building science consultant at Retrotec. Retrotec manufactures products like blower doors and duct testers for measuring air tightness and leakage in buildings.

Sam discussed his role at Retrotec, which involves training contractors on using their tools properly, product design, software testing, presenting at conferences, and running trade show booths. He talked about the demanding travel schedule this requires but also the rewards of educating the industry.

The main topic was duct leakage testing - why it's important, how it's done, interpreting the results, and investigating and fixing duct leaks when problems are found. Sam explained that while a duct leakage test provides a number, that number alone doesn't indicate if the leakage is acceptable or problematic. However, it points technicians in the right direction for further investigating issues like comfort problems, indoor air quality concerns, or high energy bills.

He provided tips on using tools like smoke tests and thermal cameras to visually identify leaks, checking common leak areas like connections and return duct penetrations, and the value of testing before and after making repairs to verify the work. Sam also discussed using low-cost manometers for other tests, like checking room pressure imbalances caused by duct leaks.

Topics covered included:

• Sam's role and work at Retrotec
• The importance of duct leakage testing
• How duct leakage tests are performed
• Interpreting duct leakage test results
• Common duct leak sources like connections and return penetrations
• Methods for pinpointing and verifying duct leaks
• Using manometers for other diagnostic tests
• Tips for contractors getting started with duct testing

Learn more about Retrotec's resources at https://retrotec.com/.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Purchase your virtual tickets for the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

Subscribe to our podcast on your iPhone or Android.

Subscribe to our YouTube channel.

Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.