Home > Companies > Custom Audio Designs Ltd > Fire Retardant Duct Foam

Used for internal and external duct linings, thermal/ acoustic machine linings and suspended ceiling absorptive panels. It can also be used as part of composites combined with acoustic barrier materials. It is extremely versatile and highly adaptive. This product is also known as PUNF foam, FR foam and Pyrosorb.


  • Designed to meet British Building Regulations.
  • Available in sheet form.
  • Flexible, easy to cut and install.
  • CFC and HCFC free.
  • Various facing options for improved low frequency absorption (often required for industrial noise issues).
  • Optional self-adhesive backing.

Also known as PUNF foam, FR foam, Fireseal and Pyrosorb.

Standard product features

Sheet size:

1000 x 1200 mm.



Fire rating:

  • BS 476-6 and BS 476-7: Class 0.
  • FMVS302: Zero burn rate, self-extinguishing.
  • CAA8/ FAA: Pass all grades.
  • UL94: Pass rating 94-V-0.
  • PSA/ FR3: Passes source 5.
  • ASTM 1692 1974: Resists ignition.

Acoustic performance:

Refer to manufacturers data sheets.


Approximately 80–90 kg/m³.

Thermal conductivity:

0.052 W/mK.

Elongation at break:

188 %.

Indentation hardness:

156 N.

Operating temperatures:

-30°C (minimum) to 110°C (maximum intermittent), 80°C (maximum continuous).


Sheet size:

Custom sizes can be produced, consult manufacturer for details.

NBS Specification

NBS Create logo
This product is associated with the following NBS Create clause:
90-90-40/360 Phenolic foam insulation

Product specification

An important note about specifying



Custom Audio Designs Ltd


+44 (0)1730 269572

Product reference

12 mm thickness, plain.
12 mm thickness, adhesive backed.
25 mm thickness, plain.
25 mm thickness, adhesive backed.
50 mm thickness, plain.
50 mm thickness, adhesive backed.


[ ______ ]


 - Type:
[Not required]
Black/ white weave locked glass cloth.
White polyurethane-coated glass cloth.
Black/ white polyurethane film.
Perforated black/ white/ grey PVC facing.
Aluminium foil laminated to glass fibre fabric.
Reinforced aluminium foil.
Metalized polyester film.
Metalized polyester film with scrim.
Black viscose tissue.
Spray applied black/ white/ grey PVC.
 - Self-adhesive foam:
[Not required]

Manufacturer details

5 Ridgeway Office Park,
Bedford Road,
Hampshire, GU32 3QF
Tel +44 (0)1730 269572
Fax +44 (0)1730 265846
NBS Plus