Egoza concertina wire is supplied in coils of fixed length, so miscalculations often lead to surpluses, installation delays, and project cost overruns. Below is a step-by-step method that takes into account angles, gates, and installation height, allowing you to order the exact meterage in advance.
Step 1. Perimeter Survey
- Walk around the boundary and record the length of each straight section to within ±0.1 m.
- Mark corners sharper than 135° – for these, apply an additional factor of 1.05.
- Note the number of gates and their widths.
Step 2. Choosing the Diameter and Stretching Coefficient
- Ø 400–600 mm – coefficient 1.3 (installation on top of an existing fence).
- Ø 900–1200 mm – coefficient 1.6 (independent ground barrier).
- Ø 1200 mm and above – coefficient 1.9 (double concertina or ground-mounted installations).
Basic Meterage Formula
Section length × stretching coefficient.
Example: 48 m straight section × 1.6 = 76.8 m of concertina wire needed.
Adjustments for Angles and Gates
- For each sharp angle, add 5% to the length of the adjacent sections.
- For swing gates wider than 4 meters, add an extra 2 meters for securing loops.
Verification Using the Control Table
Check the concertina wire table – it lists the available coil lengths. Round up to the nearest available length and add a 3% reserve for trimming defective loops.
Common Calculation Errors
- Ignoring diagonal spans – increases material consumption by 8–10% after installation.
- Summing the outer and inner diameters of a double concertina instead of multiplying by two.
- Failing to account for reserve material at gates – leading to distorted loop spacing and “crushed” sections.