Chase Corporation offers several styles of fiberglass-based tapes that can effectively serve as flame barriers in various types of cable applications. One of the primary physical characteristics of these tapes is their flexibility, which allows for tightly wrapping a cable without the tape cracking or inhibiting the flexibility of the cable. The other, of course, is their resistance to burn, as measured by the tapes’ Limiting Oxygen Index (LOI).
Simply put, LOI is the minimum concentration of oxygen that will support combustion of a polymer. It is measured by passing a mixture of oxygen and nitrogen over a burning specimen and reducing the oxygen level until a critical level is reached. Plastics and cable materials are tested for their LOI values at both ambient temperature and elevated temperature to understand their oxygen requirements under actual fire conditions. Reference ASTM 2863-19 and ISO 4589-2.
Materials with LOIs above 21% are considered to be fire retardant materials, as they are unlikely to support combustion in air. As a reference point, PET film has an LOI of only 18%, which means it burns very easily in air, while polyimide film has an LOI of 37%.
Chase Cable Materials offers three types of flame-retardant tapes, all with superior LOI performance:
- Chase and Sons® S203 -- a glass fabric impregnated with a cured silicone coating designed for high-temperature, high-strength binding applications. It typically is used in power cable applications. S203 has a total thickness of 0.004 inches and an LOI of >37%, giving it very good flame retardant and self-extinguishing characteristics.
- Chase and Sons® S378 – a heat and flame barrier tape similar in construction to S203 but thicker. S378 is 0.0075 inches thick, affording higher tensile strength for binding larger cables. S378’s LOI is >21%.
- POWERLINE® NT185S -- a fiberglass fabric treated on both sides with an acrylic-based flame-retardant coating. NT185S is rated as low smoke and halogen free as defined in IEC 61249-2-21 and has an LOI of>70%, making it an ideal flame barrier tape for use in copper or fiber optic plenum rated cables where UL 94 requirements must be met. With a thickness of 0.005 inches, NT185S is flexible enough to be wrapped helically around a cable or applied longitudinally.
For additional information or samples of Chase products please contact your Chase sales representative.