The UL-timate Test: What It Means to Be UL Listed

Thursday March 28, 2024

Becoming UL Listed is one of the most sought-after UL certifications. For many companies and organizations, including OSHA, a UL certification mark has become a literal stamp of approval for safety, security, and sustainability.


For this reason, Ideal is proud to say that several of our products are UL Listed. While a UL Listing, or certification in general, has become required for code compliance in some HVAC applications, it also ensures confidence in our products’ performance and quality.


Below, we’ve taken a closer look at what exactly a UL certification is, what goes into receiving one, and which of our products are UL Listed.



What is UL Certification?


Ideal Seal 2000. Note the UL Listed mark on the left side of the label.

UL, once known as Underwriters Laboratories, is a third-party safety organization that sets safety testing and compliance standards for a variety of products and services across various industries.


There are three tiers to UL certification: UL Recognized, UL Classified, and UL Listed. Let’s take a closer look at each tier:


  • UL Recognized: applies to components that make up a larger product or mechanism, such as factory machinery.
  • UL Classified: applies to stand-alone products that are tested and evaluated for specific requirements under a Standard set by UL.
  • UL Listed: applies to stand-alone products that meet all requirements under a Standard set by UL.

Of these certifications, our products fall under both UL Classified and UL Listed. Of the two, UL Listed is the more difficult to achieve due to the cost, time, and stringency involved in the process. To become UL Listed, products undergo a rigorous and thorough battery of tests to meet several performance requirements, which can differ depending on the product’s use.



UL Standard Testing


Let’s look at how UL certification works: UL sets the specifications and requirements for a product; this is known as a Standard. When a product is tested, it can be tested against a specific requirement in a Standard for a UL Classified certification, or against all requirements to become UL Listed. All manufacturers are held to the same Standards when it comes to certification.


To receive a UL 181 listing, the listing that applies to HVAC tapes used to seal air duct and air connectors, our tapes are tested for the following requirements, among others:


  • Backing Thickness
  • Peel Adhesion
  • Shear Adhesion in three temperature ranges
  • Tensile Strength
  • Fungi/Mold Resistance
  • Surface Burning Characteristics (Flame Spread/Smoke Developed)
  • Temperature/Pressure Cycle
Ideal Seal 2000 at work. Note the UL Listed printing on the tape.

Due to our products being used to seal ducts that carry breathable air, they are required to be UL Listed. This ensures that they meet the stringency of these tests and will perform as expected.


Once a product is certified as UL Listed, it’s required to have its certification printed on the product itself for identification and code compliance. This includes the UL mark, the word Listed, as well as company identification and a specific control number.


However, while all Listed products must be printed, not all printed products are necessarily UL Listed. It’s important to distinguish between the two to ensure you’re using the proper product required for your needs.


In order to stay UL Listed, products must continue to meet the above requirements. This is enforced by regular audits and inspections by UL to ensure products are complying with safety standards.



Our UL Listed Products


Ideal Seal 587 A/B

There are multiple UL 181 listings that HVAC tapes can qualify for depending on their application, and you’ll find our products typically listed under two of them: UL 181A-P and UL 181B-FX. UL 181A-P is the standard for pressure-sensitive aluminum tapes used on rigid air ducts or duct board, while UL 181B-FX is the standard for tapes used on flexible air ducts. 


All our UL 181 Listing requirements fall under UL’s ALKW section for AIR DUCT AND AIR CONNECTOR CLOSURE SYSTEMS.  In these HVAC applications, UL sets the standards for the ducts as well as the installation accessories.


Our Ideal Seal® 2000 tape is a 2 mil aluminum foil coated tape with a permanent acrylic adhesive, and is listed under both UL 181A-P and UL 181B-FX. Used to seam and seal HVAC duct systems, 2000’s conformable foil backing makes for easy handling, while its exceptional adhesive system can perform in a wide range of temperature and humidity conditions.



Flex Seal 450 in both black and silver

Ideal Seal 587 A/B is another product that meets requirements for both listings. It can be used for many of the same applications as 2000, but with a slightly thicker aluminum backing at 2.3 mil. It can also be used in temperatures as low as -25°F (or -31.7°C).


Ideal’s FlexSeal 450 is also UL 181B-FX Listed. It is a self-wound film product coated with a high-performance acrylic adhesive, designed specifically for use on flexible air ducts and connections. It is available in black and silver based on your needs.


Another listing you’ll find on one of our products under is UL 181A-H, which is the standard for heat-activated aluminum tapes used on rigid air ducts. This standard applies to our Ideal Seal 490, which uses a heat activated adhesive system to seal joints and seams in fiberglass duct board fabrication. It’s also printed with temperature indicators that change color when the proper amount of heat is applied.



Through receiving a UL Listing, our products have demonstrated their reliability and sustainability. And with a variety to choose from, you can be confident we have a solution for your HVAC needs. Be sure to visit our UL 181 page to find out more about our UL Listed products!

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