Flame-Retardant Tape (NWPT)
Halogen-free flame barrier and separator for CPR-compliant cable construction
Flame-Retardant Tape (NWPT)
The flame-retardant tape (NWPT) is a composite material made of non-woven polyester fabric impregnated with a halogen-free, high-efficiency flame-retardant compound. This construction combines the separating and bundling function typical of non-woven polyester with flame-retardant properties that contribute to compliance with CPR reaction-to-fire standards, acting as an additional thermal barrier that slows flame propagation and reduces opaque smoke emission.
In cables for permanent installation in buildings, the Construction Products Regulation (CPR) sets reaction-to-fire requirements that affect every cable component. With an oxygen index (LOI) of 26% per ASTM D2863, NWPT delivers a self-extinguishing behaviour that allows inner cable layers to contribute positively to the final classification, making it easier to reach classes Cca, B2ca or B1ca.
Beyond its flame-retardant properties, the non-woven structure provides excellent separating function, enabling clean peeling between cable components during installation. Tensile strength ≥60 N/15 mm ensures reliable behaviour in high-speed industrial taping, without tearing or deformation that could compromise process continuity.
Short-term thermal stability of 230°C makes the tape compatible with the extrusion processes typically used in cable manufacturing, while a continuous service temperature of 90°C per IEC 216 preserves its properties throughout the cable's service life under normal operating conditions.
The halogen-free formulation ensures that, in the event of combustion, no corrosive or toxic gases are generated that could compromise escape routes or damage sensitive electronic equipment nearby.
How to choose the right one?
NWPT is the right choice when both a separating function and a positive contribution to the cable's CPR classification are required. The selection vs. alternatives depends on specific construction requirements.
Key features
| Feature | Value | Benefit |
|---|---|---|
| Oxygen Index (LOI) | 26% | Superior self-extinguishing behaviour |
| Process thermal stability | 230°C | Compatible with jacket extrusion |
| Service thermal stability | 90°C | Integrity over the cable's service life |
| Tensile strength | ≥60 N/15 mm | High-speed taping without breaks |
| Halogens | Halogen-free | Minimal toxicity in case of fire |
NWPT vs. alternatives
| Factor | NWPT (flame-retardant) | Mica Tapes | Standard NWP |
|---|---|---|---|
| Primary function | Reaction to fire (CPR) | Circuit integrity | Separation |
| Oxygen Index (LOI) | 26% | — | ~21% (standard) |
| Main standard | CPR (EN 13501-6) | IEC 60331, EN 50200 | — |
| Halogen-free | Yes | Yes | Yes |
| Service temperature | 90°C | Up to 1000°C | 90°C |
| Stripping ease | Excellent | Good | Excellent |
Selection by target CPR class
| CPR class | Requirements | NWPT application |
|---|---|---|
| Eca | Basic | Not usually required |
| Dca | Limited | May contribute to classification |
| Cca | Improved | Recommended in inner layers |
| B2ca | High | Usually required |
| B1ca | Very high | Required, possibly combined with mica |
Technical specifications
The values shown below come from tests run to international standards and characterise the material's behaviour both during processing and in service.
Mechanical properties
| Property | Test method | NWPT-15 |
|---|---|---|
| Thickness | ISO 9073-2 | 0.15 ±0.03 mm |
| Mass per unit area | ISO 9073-1 | 120 ±30 g/m² |
| Tensile strength | ISO 9073-3 | ≥60 N/15mm |
| Elongation | ISO 9073-3 | ≥8% |
| Moisture content | ISO 287 | ≤8% |
Fire behaviour properties
| Property | Test method | NWPT-15 |
|---|---|---|
| Oxygen Index (LOI) | ASTM D2863 | 26% |
| Halogens | — | Halogen-free |
Thermal properties
| Property | Test method | NWPT-15 |
|---|---|---|
| Short-term thermal stability | Q/TR.J02.031-2000 | 230°C |
| Long-term thermal stability | IEC 216 | 90°C |
Construction
| Component | Material |
|---|---|
| Backing | Non-woven polyester |
| Treatment | Flame-retardant compound |
| Halogens | Halogen-free |
Values shown are typical and do not constitute binding specifications.
Available variants
Alternative thicknesses
- Other thicknesses available on request. Please contact us with your specific application requirements.
Alternatives by requirement
- Mica tapes — when circuit integrity is required (IEC 60331)
- Standard NWP — when only separation is needed, with no fire properties
Delivery formats
We tailor the supply to each production line's technology to maximise efficiency and minimise downtime.
Pad / Roll (pancake)
Pancake format for taping lines
Spool
Reel for automatic taping lines
Note: spool handling requires care to avoid lateral damage to the product. Other formats and dimensions available on request. Custom slitting service available.
Application sectors
Aplicaciones típicas
| Aplicación | Función del producto |
|---|---|
| CPR class Cca-B1ca cables | Contribution to reaction-to-fire classification |
| LSZH cables | Halogen-free separation with flame-retardant properties |
| Building cables | Thermal barrier between components |
| Railway cables | EN 45545 compliance (consult specific requirements) |
Need technical advice?
Selecting the right flame-retardant material requires analysis of the full cable construction and the target CPR classification. Our technical team can advise on the construction design to reach the required class.
Custom slitting
Up to 1200 mm width, ±0.50 mm tolerance
View service
Spooling
Pad to spool conversion for taping lines
View serviceWe process material from our stock or material supplied by the customer.
Need technical advice?
Our technical team is available to help you select the optimal material for your application.
Local stock in Barcelona · Immediate delivery in Spain and Portugal