EMI / RFI Shielding Mesh is used for attenuating electromagnetic and radio-frequency interference through vents, windows and enclosures while still passing air and light. IEEE 299 is the reference cited for it on drawings, datasheets and purchase orders.
What IEEE 299 Means for EMI / RFI Shielding Mesh
The dimensions in the table below are supplied to suit IEEE 299. Where the standard sets requirements for the finished appliance, device or system, compliance testing of that assembly stays with its manufacturer; we supply the metal mesh part to the drawing and can provide material certificates and dimensional reports with the shipment.
EMI / RFI Shielding Mesh Dimensions
| Mesh count | Wire diameter (mm) | Aperture (mm) | Open area (%) | Material | Shielding @ 1 GHz (dB) |
|---|---|---|---|---|---|
| 22-Mesh | 0.115 | 1.040 | 81 | Copper | 50 |
| 60-Mesh | 0.110 | 0.313 | 55 | Copper | 65 |
| 100-Mesh | 0.110 | 0.144 | 32 | Phosphor bronze | 75 |
| 100-Mesh Monel | 0.110 | 0.144 | 32 | Monel 400 | 75 |
| 145-Mesh | 0.056 | 0.119 | 46 | SS304 | 70 |
Specifying EMI / RFI Shielding Mesh Beyond the Standard
- Frequency range: Finer mesh and thicker wire raise attenuation at higher frequencies; state the band to be shielded.
- Conductivity & corrosion: Copper and phosphor bronze conduct best; Monel 400 and stainless resist corrosion in marine or outdoor use.
- Bonding: Specify a continuous, low-resistance perimeter bond — the mesh only works when grounded all round.
When EMI / RFI Shielding Mesh Is Not the Right Choice
Not a fire, thermal or ballistic barrier — combine with other materials where those properties are needed.
