HOME PRODUCTS RESOURCES ABOUT CAREERS NEWS TRADE SHOWS CONTACT FAQs How are Thermaflex®'s pressure ratings determined? Thermaflex’s UL Listed pressure ratings are determined by testing duct in straight lengths, at ambient temperatures and witnesses by UL. Testing is done in a static condition (no airflow). The test sample is sealed airtight on both ends and pressurized to 2 times the manufacturers desired rated pressure for a test period of one hour. This applies to both positive and negative water column pressure claims. These tests can also be witnessed by UL. Thermaflex performs some additional tests in accordance with the Air Diffusion Council, FD 72-R1 Flexible Duct Test Code. The purpose of these tests is to simulate a variety of realistic conditions, which may exist in actual installations. The ADC tests include a 90 degree bend, heated air at continuous and intermittent temperatures, for a test period of 168 hours. The resulting “Recommended Operating Pressures” are intended to give the contractor and/or engineer a responsible guideline within which to design the duct system. What are Thermaflex's pressure ratings? Can any of THERMAFLEX's Flexible Duct be exposed to ultraviolet sunlight? What is the thickness of Thermaflex insulation? Does THERMAFLEX manufacture an acoustical duct? Does THERMAFLEX have a plenum rated duct? What materials are required/allowed to be used when hanging or supporting flexible duct? How does duct condensation or sweating occur? Have Thermaflex's products been tested for mold growth and humidity? What is the difference between Air Ducts and Air Connectors? Does Thermaflex manufacture duct that can be used for dryer venting? Can screws be used to fasten flexible duct core? Do you have a sales related question? Contact Thermaflex® National Sales Headquarters & Customer Service Dept. Box 927 (381 Carwellyn Road) Abbeville, SC 29620 1-800-459-4822 800-459-3828 For general inquiries, click the button below to fill out our contact form. EMAIL US Connect With Us! SISTER COMPANIES AFFILIATES © 2021 THERMAFLEX | Anti-Modern Slavery & Transparency