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How Duct Tape Got Its Name (and Why It Shouldn’t Be on Ducts) – Short #264

By Bryan Orr

In this short podcast episode, Bryan explains how duct tape got its name and why it shouldn't actually be used on ducts. Duct tape is a versatile home DIY-fix tool, but despite its name, it wasn't initially made to seal ducts at all.

In 1943, we were in the thick of World War II, and ammo shipments were sealed with wax and paper tape. These were often not durable or difficult to open. Johnson & Johnson developed a tape with rubber adhesive on a cotton duck cloth backing (which was already widely used for military uniforms and tent fabrics). This new tape was nicknamed “duck” tape due to the material and its waterproof abilities (like the waterfowl). A woman named Vesta Stoudt informed President FDR about duct tape, and the War Production Board began using it in wartime supply packaging.

After the war, America had a housing boom in the 1950s, which included the demand for forced-air heating and cooling systems. Marketers thought the tape could seal the ducts in those homes, so they changed the color to match sheet metal and rebranded it as “duct tape.” In the 1960s, this tape was available in retail outlets with the “duct tape” branding.

Unfortunately, in tests by the Lawrence Berkeley National Lab, duct tape failed miserably at sealing the ducts because the rubber adhesive dries out under heat, and dust weakens the adhesive. As a result, many building codes ban duct tape on ducts (spearheaded by California). Instead, UL-listed foil tape and mastic are approved for sealing ducts. However, duct tape still became famous for its versatility as a patching material. It's prevalent in pop culture and has been used in television shows and even in space.

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#duct #duct sealing #duct tape #ductwork #hvac

Author:

Bryan Orr

Company: HVAC School

Position: Founder

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Our latest Podcast

HVAC School – For Techs, By Techs

Real training for HVAC ( Heating, Ventilation, Air Conditioning and Refrigeration) Technicians. Including recorded tech training, interviews, diagnostics and general conversations about the trade.

In this informative episode, Bryan and Bert dive deep into gas appliance safety and combustion analysis from the unique perspective of Florida HVAC technicians. While they humorously acknowledge that Florida’s mild winters mean they don’t work on gas furnaces daily, they make a compelling case that this actually makes their training even more critical. When technicians only encounter gas appliances occasionally, the stakes are higher—which is why they’ve developed rigorous protocols to ensure safety every single time.

The conversation covers everything from the basics of gas leak detection to the nuances of carbon monoxide monitoring, combustion air zones, and proper venting. Bryan and Bert share real-world stories of dangerous situations they’ve encountered, from exploding pool heaters to improperly capped gas lines at vacation rentals. Their approach emphasizes that every gas leak is your problem when you’re on site, regardless of why you were originally called out. This episode is packed with practical wisdom for both seasoned professionals working in gas-heavy markets and those who encounter these systems less frequently.

Throughout the discussion, the hosts stress fundamental safety principles that apply across all markets: using your nose to detect leaks, understanding the difference between unspent gas and carbon monoxide, ensuring proper combustion air zones, and never ignoring warning signs like delayed ignition or flame rollout. They also tackle common misconceptions about equipment like flexible gas connectors, orphaned water heaters, and the real risks of cracked heat exchangers.

The conversation wraps up with important reminders about company lockout/tagout procedures, the critical importance of low-level carbon monoxide detectors, and the tools every technician should carry. Bryan and Bert’s candid, no-nonsense approach makes complex safety topics accessible while never losing sight of how serious the consequences can be when gas work goes wrong.

Topics Covered

Gas leak detection and response protocols – Why every gas leak on site becomes your responsibility, using your nose as the first line of defense, and never leaving a leak for someone else to fix
Carbon monoxide safety and monitoring – Understanding CO as a combustion byproduct, the limitations of standard UL-rated detectors, and the critical importance of low-level CO monitors
Combustion air zones and depressurization – Identifying risks from sealed spaces, return air leaks, exhaust fans, and other equipment that can create dangerous negative pressure
Delayed ignition and flame rollout – Recognizing warning signs, understanding causes, and why you should never ignore scorched wires or tripped rollout switches
Proper gas line assembly and materials – Selecting appropriate materials for different environments, avoiding flexible connector failures, and ensuring proper sizing
Combustion analysis fundamentals – Measuring CO levels in the flue, targeting air-free CO under 100 ppm, and understanding when adjustments are needed
Natural draft vs. induced draft systems – Differences in safety considerations, orphaned water heaters, and the myth of oversized flue pipes
Venting requirements and back drafting – Identifying improper venting, looking for evidence of back draft on water heaters, and ensuring proper flue design
Gas pressure testing and adjustment – When to adjust and when not to, reading data tags, and understanding that most flame problems are air-related, not gas pressure
Cracked heat exchangers in context – Why they’re less common in warm climates, the role of proper airflow, and focusing on actual safety risks vs. edge cases
Tools and equipment recommendations – Combustion analyzers, personal protective CO detectors, combustible gas detectors, precision manometers, and low-level CO alarms
Lockout/tagout procedures – Following company protocols, communicating clearly with customers, and balancing safety requirements with homeowner autonomy

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

Purchase your tickets or learn more about the 7th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

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.

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