Phenolic Pre-insulated Duct

The Phenolic Pre-Insulated HVAC Ductwork System should be UL Listed as a Class 1 Air Duct, to Standard for Safety UL 181, when fabricated to a specification clearly defined by UL and by SMACNA PDCS (Phenolic Duct Construction Standards).

Properties: The Phenolic System comprises Phenolic Panels, which are faced on both sides with an embossed aluminum foil that is lacquered with corrosion-resistant polymer varnish. Both facings are auto-hesively bonded to the insulation core during manufacture.

The core of Phenolic Panels is a high-performance rigid thermoset phenolic insulant manufactured with a blowing agent that has zero Ozone Depletion Potential (ODP) and low Global Warming Potential (GWP).

The core of Phenolic Panels is fiber–free, odorless, non–tainting, non–deleterious, chemically inert, and safe to use. They will also resist attack from mold and microbial growth. The apparent density of Phenolic Panels is 55-60 kg/m3, when tested to BS EN 1602: 2013.

The thermal conductivity (λ-value / k-value) of Phenolic Panels is quoted by ASTM C 518: 0.0285 W/m.K.

UL Listing: Ductwork fabricated from Phenolic System is UL listed as a Class 1 Air Duct, to Standard for Safety UL 181 (Underwriters Laboratories: Factory Made Air Ducts & Air Connectors), when fabricated to a specification clearly defined by UL. The following tests have been completed and passed to achieve the UL 181 listing: Surface burning, flame penetration, mold growth and humidity, puncture test, static load, impact, erosion, pressure and collapse, corrosion, and leakage.

Operating Recommendations & Limitations: It is recommended that ductwork fabricated from the Phenolic System is used for operation as supply, return, fresh, and exhaust air ductwork for heating, ventilation, and air-conditioning systems within the following limits:

Mean Air

Velocity (Max.)

15 m/s
Design Pressure (Max.)




Positive: 1000 – 1750 Pa
Internal Air Temperature of -25ºC to + 80ºC during continuous operation
Unlimited (PIR System fabrication techniques and procedures are strictly observed)

Fire: Phenolic Panels, and their rigid thermoset insulation core, are Class 0 as defined by BS 476 Part 6 & Class 1 as defined by BS 476 Part 7.

Meets 25/50 requirements as per ASTM E84/UL 723.

Durability: According to ASHRAE and CIBSE, the indicative life expectancy of HVAC ductwork for building services is approximately 30 years.

Phenolic Panels can have an indefinite life. Its durability depends on the supporting structure and the conditions of its use.

Ductwork should not be used in the following applications:

  • Conveyance of solids;
  • Fire-resistant ductwork;
  • Kitchen/grease hood exhaust systems;
  • Chemical, fume, or smoke exhaust systems;
  • Where combustible matter readily collects inside the ductwork;
  • Adjacent to any mechanical/electrical sources of extreme heat;
  • Outdoor/underground use without mechanical and/or weather protection; and
  • Where the failure of any type that does not include automatic maximum temperature.
Pre-insulated Duct
Volume Control Dampers