UL 94 HB flame-rated rubber meets Underwriters Laboratories (UL) requirements for resistance to horizontal burning. This flammability rating is part of the larger UL 94 standard but is different from UL 94 V0, UL 94 V1 and UL 94 V2, all of which apply to vertical burning.
UL 94 HB is less stringent than these other standards, but rubber products that resist horizontal burning are needed for data centers, EV charging stations, solar panels, and instrument enclosures. Elasto Proxy supplies a certified UL 94 HB EPDM gasket material for these and other applications.
Keep reading to learn more about UL 94 HB or contact Elasto Proxy to discuss your application.
What is UL 94?
UL 94 is a standard from Underwriters Laboratories (UL) that defines fire tests for polymers, a category of materials that includes rubber and plastic. UL 94 contains different flame classifications or ratings, each of which has its own test procedure.
Certification or compliance with UL 94 is important for fire safety, but it’s also voluntary. In other words, UL 94 is not a government regulation. Because UL 94 rubber costs more, you’ll want to make sure that your application requires it and that you’re meeting the correct flammability rating.
What is UL 94 HB?
UL 94 HB defines a horizontal burn (HB) test for a material specimen that is exposed to a small open flame that is 20 mm high. This specimen, or sample, of the material is placed horizontally and a flame is applied to one end for 30 seconds or until the flame reaches a specified mark.
Materials that pass the UL 94 HB are self-extinguishing. More specifically, the specimen must meet either of the following conditions.
- The burn rate does not exceed 76 mm/min (3 in/min) for materials less than 3 mm thick, or
- The material self-extinguishes before the flame travel 100 mm (4 inches)
Prior to testing, the material specimen is kept for 48 hours at 23°C (73.4°F)
What is UL 94 HB Flame Rated Rubber?
UL 94 HB flame rated rubber includes ready-to-fabricate materials and finished products that meet UL 94’s horizontal burn standard. Examples include extrusions, cut lengths, molded parts, seals, and gaskets. UL 94 rubber comes in various compounds as a sponge or solid material.
UL 94 HB EPDM rubber combines resistance to horizontal burning with the broad environmental resistance that ethylene propylene diene monomer (EPDM) rubber offers. In addition to water, weather, and outdoor temperature resistance, EPDM is durable and abrasion resistant.
UL 94 HB flame retardant silicone sponge is also available. Silicone can’t match EPDM’s durability and abrasion resistance, but it withstands significantly higher temperatures. Yet silicone also costs more. During compound selection then, consider MTAP and ask Elasto Proxy for assistance.
What is Elasto Proxy’s UL 94 HB Rubber?
Elasto Proxy supplies a UL 94 HB EPDM sponge rubber for flame retardant gaskets. This UL certified material is black in color and has a Yellow Card for a 5.7 mm (0.225 in.) sample. Our standard UL 94 HB rubber is available for distribution, but we can also send you custom extrusions or ready-to-install gaskets.
For data centers, Elasto Proxy offers a standard UL 94 HB EPDM sponge rubber product, EC28-101-EM, that fits panels 3.175 mm (0.125 inch) thick. This medium-durometer bulb trim is reinforced with a spring steel clip for greater impact resistance.
Elasto Proxy can also supply you with custom extrusions of this UL 94 HB EPDM sponge rubber in different sizes and shapes. The minimum economic order quantity is 762 meters (2500 feet), and it take about eight weeks for a custom die and sample.
Find UL 94 HB Flame Rated Rubber
Do you need UL 94 HB flame rated rubber for data centers, EV charging stations, solar panels, or instrument enclosures? Elasto Proxy has a Yellow Card for a certified UL 94 HB EPDM sponge material that we invite you to learn more about. Contact us for more information.
