Fire-safety claims on house wire are easy to make and hard to check — unless you know which four numbers to ask for. This chart is the reference.
The four parameters
| Parameter | Test | What it tells you | Target value |
|---|---|---|---|
| Oxygen index | ASTM D2863 | Minimum oxygen needed to sustain burning. Air is ~21%, so anything above that self-extinguishes. | ≥ 29% (≥ 31% strong) |
| Temperature index | ASTM D2863 | Temperature at which the material burns in normal air. | ≥ 250°C |
| Smoke density | IEC 61034 | How dense the smoke is — whether you can still see an exit. | Lower is better (≤ 10% is strong) |
| Acid gas / halogen | IEC 60754 | Corrosive, toxic gas released while burning. | Low; ≤ 0.5% = halogen-free |
How the grades compare
| Grade | Flame retardant | Low smoke | Halogen | Typical standard |
|---|---|---|---|---|
| FR | Yes | No | Present | IS 694:2010 |
| FR-LSH | Yes | Yes | Reduced | IS 694:2010 |
| HR-FR-LSH | Yes | Yes | Reduced | IS 694:2010 |
| HFFR | Yes | Yes | Essentially none | IS 17048:2018 |
Note the distinction: “low halogen” and “halogen-free” are different claims. Low halogen means reduced. Halogen-free means measured at or below roughly 0.5%, and is certified under IS 17048:2018.
Reading the numbers correctly
- Oxygen index is the headline figure. It is the clearest single indicator of whether insulation will keep burning once the flame source goes away.
- Smoke density is the survival figure. Most fire deaths involve smoke, not flame. Lower is better: around 10% for a strong HFFR compound versus roughly 60% for standard PVC.
- Halogen content is the damage figure. Acid gas harms lungs and corrodes equipment in rooms the fire never reached.
- Temperature index is the early-warning figure. It matters in a developing fire, before flame arrives at the cable.
Where each grade makes sense
| Application | Sensible minimum |
|---|---|
| Outbuilding, garage, temporary wiring | FR |
| Standard independent house | FR-LSH or HR-FR-LSH |
| Apartment, especially high-rise | HR-FR-LSH or HFFR |
| Hospital, school, public building | HFFR |
| Basement, server room, no natural ventilation | HFFR |
If a manufacturer cannot supply all four figures for a wire, treat the fire-safety claim as unverified.
How the APAR house-wire range compares
Rather than describe this in the abstract, here is APAR’s own published fire-performance data across the range, so you can see how the grades actually differ:
| Wire | Grade | Oxygen index | Smoke density | Acid gas / halogen | Temp rating |
|---|---|---|---|---|---|
| APAR Shakti FR-PVC | FR | ≥ 29% | ≤ 60% | ≤ 20% | 70°C |
| APAR Shakti FR-LSH | FR-LSH | ≥ 29% | ≤ 60% | ≤ 20% | 70°C |
| APAR Green Wire HR-FR-LSH | HR-FR-LSH | ≥ 29% | ≤ 60% | ≤ 20% | 85°C |
| Anushakti HR-FR-PVC (e-beam) | HR-FR-PVC | > 29% | 75% | 20% | 105°C |
| Anushakti HR-FR-LSH (e-beam) | HR-FR-LSH | > 29% | 75% | 20% | 105°C |
| Anushakti Fire Protekt EBXL HFFR | HFFR | ≥ 31% | ≤ 10% | ≤ 0.5% | 120°C |
The pattern is worth reading carefully. Across the PVC-based grades the fire numbers are broadly similar — the differences are in heat rating and features like rodent resistance. The step change comes with HFFR: smoke density falls from around 60% to 10%, and halogen from 20% to 0.5%.
That is the difference between a corridor you can see through and one you cannot, and it is why the halogen-free grade exists.
Compare the specifications yourself
Every APAR house wire publishes its full specification — conductor construction, resistance in Ω/km, fire-performance figures, applicable standards and current ratings for both conduit and clipped installation:
- Anushakti Fire Protekt EBXL HFFR — halogen-free, e-beam cross-linked, 120°C
- Anushakti HR-FR-LSH — e-beam, heat-resistant to 105°C, low smoke
- Green Wire HR-FR-LSH — eco-friendly compound, rodent and termite resistant
- Shakti FR-LSH — flame-retardant, low smoke, low halogen
Use the comparison to judge APAR against any other manufacturer. If a competitor cannot supply the same figures, that itself tells you something.
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