Everything a buyer or an estimator needs to specify concertina coil: sizes, blade types, the standard 600 mm tender item, and how much steel is in a coil and in a metre of fence — with a calculator.
The standard Indian wall-top coil is 600 mm diameter punched tape concertina: 0.52 mm galvanized razor tape clinched on a 2.5 mm high tensile spring core, 50 turns per 6 m of run. One coil carries about 7.7 kg of steel before clips — about 1.3 kg per metre of run, or 2.0 kg per metre of fence with the usual nine horizontal lines of razor tape.
All diameters are made to order: 450, 500, 600, 730, 900, 980 and 1050 mm. 450–600 mm coils go on wall tops and fences; 730–1050 mm coils on open ground or as an outer coil. Published reference coils:
| Reference | Diameter | Turns | Clips | Run per coil | Weight |
|---|---|---|---|---|---|
| Tender pre-bid answer (ICTS-TIFR) | 610 mm | 40–45 | 125–127 | up to 5.5 m | 7.25–7.50 kg |
| Defence spec (CQA Pune, 2004) | 610 mm closed / 580 mm open | 50 | 129 | 6 m | 9.0 kg ±5% |
| Defence spec, large coil (CQA Pune) | 1050 mm closed / 915 mm open | — | — | 15 m | — |
| Blade | Barb length | Barb spacing | Tape | Where it fits |
|---|---|---|---|---|
| BTO-10 | 10–12 mm | 26 mm | 0.5 mm | Short barb — dense, neat, for wall tops in towns |
| BTO-22 | 22 mm | 34 mm | 0.5 mm | Medium barb — the usual choice for Indian boundary walls |
| BTO-30 | 30 mm | 34 mm | 0.5 mm | Long barb — a harder obstacle for fence lines |
| CBT-60 | 60 mm | 96 mm | 0.6 mm | Long, hooked barb — perimeters and high security |
| CBT-65 | 65 mm | 100 mm | 0.6 mm | Longest barb — defence and prison-grade perimeters |
The number in the name is roughly the barb length. Dimensions follow the common industry chart; a tender may name its own profile and tolerance.
| Type | What it is |
|---|---|
| Single coil (spiral) | One helix of razor tape on its core, stretched along the run and held at a set pitch by clips. The standard wall-top coil in Indian tenders. |
| Cross type | Adjacent loops clipped to each other at points round the circumference, so the coil opens into a criss-crossed barrier that is harder to push through. |
| Flat wrap | Loops flattened into a panel that lies close to a wall or fence face — neat where a round coil would overhang. |
| Straight razor tape (RBT) | Razor barbed tape on a core, run straight between posts — the horizontal lines in a Y-angle fence. |
| Double coil | A smaller coil inside a larger one, for a deeper obstacle on open ground. |
| Part | What it specifies |
|---|---|
| Coil | Punched tape concertina coil, 600 mm diameter |
| Loops | 50 rounds per 6 m of run |
| Openable length | 10 m per coil (total run as per BOQ) |
| Spring core | 2.5 mm high tensile wire, 165 kg/mm² |
| Tape | 0.52 mm thick, 43.478 g per metre |
| Support | M.S. angle ‘Y’ posts 2.4 m or 3.0 m apart on the wall top (paid separately) |
| Horizontals | 9 lines of reinforced barbed tape (RBT) / barbed wire on the Y arms |
| Fixing | G.I. staples and G.I. clips; bolts or G.I. barbed wire tying to the angle iron |
| Unit of measurement | Running metre of fence |
A tender pre-bid answer from ICTS-TIFR, Bengaluru also asked for a minimum 125 g/m² of zinc on the tape and coils of 7.25–7.50 kg. There is no Indian Standard for concertina coil itself (IS 278 covers barbed wire), so the tender item and the purchaser’s specification govern.
A coil is one long line of razor tape on its core, wound into turns. Each turn is one circumference long, so the steel in a coil is π × diameter × turns × weight per metre of tape-on-core. With the tender’s 0.52 mm tape (43.478 g/m) on a 2.5 mm core (38.5 g/m), that is 82 g per metre of line:
| Diameter | Steel per turn (kg) | 33 turns (kg) | 50 turns (kg) | 56 turns (kg) |
|---|---|---|---|---|
| 450 mm | 0.116 | 3.8 | 5.8 | 6.5 |
| 500 mm | 0.129 | 4.3 | 6.4 | 7.2 |
| 600 mm | 0.155 | 5.1 | 7.7 | 8.7 |
| 730 mm | 0.188 | 6.2 | 9.4 | 10.5 |
| 900 mm | 0.232 | 7.7 | 11.6 | 13.0 |
| 980 mm | 0.252 | 8.3 | 12.6 | 14.1 |
| 1050 mm | 0.271 | 8.9 | 13.5 | 15.1 |
Clips add a little — the defence specification’s 50-turn coil with 129 clips is 9.0 kg. Use the calculator below for any other coil.
Steel only: clips, handles and the Y-angle posts are extra. Defaults are the common 600 mm tender item (0.52 mm tape at 43.478 g/m on a 2.5 mm core, 50 turns per 6 m, 9 horizontal lines).
Send the diameter, turns per coil (or run per coil), blade type, tape thickness, single or cross type, and the total run — or simply the tender item. We quote per coil with the weight, so it compares directly. Concertina coil → · HSN 7313 00 20, 18% GST
The usual tender item: 600 mm diameter punched tape concertina, 0.52 mm galvanized tape on a 2.5 mm high tensile spring core (165 kg/mm²), 50 turns per 6 m of run, 10 m openable length, fixed in Y-angle posts with nine horizontal lines of razor tape.
For the standard 600 mm coil at 50 turns per 6 m, about 1.3 kg of steel per metre of run; with nine horizontal lines of razor tape, about 2.0 kg per metre of fence. Clips and posts are extra.
No Indian Standard covers concertina coil itself; IS 278 is for barbed wire. Tenders specify it by their own item — diameter, turns, core and tape — and defence purchases follow CQA specifications.
BTO blades (BTO-10, 22, 30) are shorter barbs on 0.5 mm tape, used for most boundary walls. CBT blades (CBT-60, 65) are long barbs on 0.6 mm tape for high-security perimeters.
Tell us your dimensions, wire specification and quantity — we'll come back with a quotation and lead time.
