Technical Data and Material Specification
This technical page summarises composition, test performance, intended uses and handling guidance for the shielding materials we sell and use at EMF Clothing Ltd. Each material name links to its product page for ordering or deeper product details.
All our shielding fabrics and materials are tested in independent certified laboratories. Using unique simulation technology we are able to design and produce the highest specification products.
Our products are not only tested and certified for electromagnetic shielding effectiveness to international standards (ASTM D-4935-10 and IEEE 299-2006), but are also tested and certified for chemical contamination to ensure our materials are free from toxic chemicals and carcinogens such as mercury and formaldehyde.
Material specifications
Quick reference table - click a material name to open the product page.
| Material | Composition / Notes | Width | Weight | Conductivity / Intended Use |
|---|---|---|---|---|
| Silver SuperShield | Double silver-plated nylon 24% silver. Used as lining for caps & hats, head nets; also sold as raw fabric and curtains. | 1.4 m | 40 g/m² | Conductive and groundable. Recommended for curtains, canopies, technical shielding and lining garments (caps, head nets). |
| Veil (Shielding Fabric) | Open net / veil structure. Polyester 90% + Silver-Copper 10% (silver/copper threads woven into polyester). | 2.9 m | 60 g/m² | Semi-conductive; decorative shielding for curtains, canopies and nets. Not used for clothing. |
| Swiss Shield Naturell | Natural cotton base with approx. 18% copper/silver yarn integrated. Soft textile. | 2.5 m | 69 g/m² | Non-conductive surface (provides passive attenuation via embedded metal yarn). Suitable for canopies, room dividers. Not to be used for clothing. |
| LBK100 Shielding Material | High-performance metallic shielding material — engineered for structural and fixed installations rather than wearable garments. | 53 cm (roll) | 75 g/m² | High attenuation. Requires grounding in many applications. Intended for walls, panels in domestic or commercial property. |
| LBK100A (Self-Adhesive) | As LBK100 with an adhesive backing for easy installation on flat surfaces. | 53 cm (roll) | 78 g/m² | High attenuation for structural uses where adhesive backing is required for ease of installation. |
| Wallpaper Leblok Absorb | RF-shielding wallcovering for interior use - ideal base for further decoration. Ecological, non-metallic, breathable and flame-retardant. | varies | 80 g/m² | Used to both reflect and absorb RF/EMF, helping reduce reflections when full-room shielding isn’t possible or where users need to still use mobile or Wi-Fi devices. Not wearable. |
Shielding performance (attenuation)
Shielding effectiveness is measured in decibels (dB). The higher the dB number, the greater the attenuation (blocking) of the electromagnetic field. dB is logarithmic: +20 dB ≈ 10× field reduction; +40 dB ≈ 100×; +60 dB ≈ 1000×.
| Material | Representative Shielding / Attenuation | Test standard / Frequency notes |
|---|---|---|
| Silver SuperShield | 50 dB @ 1 GHz (99.999% reduction) | Measured per ASTM D4935-10 and IEEE test methods. Effective across many mobile/Wi-Fi bands used in everyday environments. |
| Veil | 45 - 25 dB (approximate; 400 MHz - 5 GHz range) | Tested in specialized EMF labs (MIL-STD and IEEE methods); attenuation varies with frequency and fabric geometry. |
| Swiss Shield Naturell | 38 dB @ 1 GHz (99.98%) | Test data and reports available — measured across a broad spectrum (600 MHz - 40 GHz in supplier report). |
| LBK100 | High attenuation - spec sheets report >80 dB in many RF bands; performance measured 1 MHz - 40 GHz (see product spec). | Ideal for RFID shielding and cyber-security–related EM shielding applications. Grounding recommended for maximum effectiveness. Also used for interior home shielding. |
| LBK100A (Self-Adhesive) | The same as LBK100 across 1 MHz - 40 GHz; adhesive backing for easy installation. | High Self-adhesive version of LBK100, suitable for interior home shielding and security-related EM/RFID shielding applications. Grounding recommended for maximum effectiveness. |
| Wallpaper Leblok Absorb | Measured attenuation varies significantly depending on frequency (see product spec). | Used to both reflect and absorb RF/EMF, helping reduce reflections when full-room shielding isn’t possible. |
Testing standards & methodology
We use only recognised measurement methods and third-party laboratories for shielding verification. Common references used for our fabrics include:
- ASTM D4935-10 - standard test method for measuring the shielding effectiveness of planar materials (TEM cell / coaxial fixtures).
- IEEE Std 299 - methods adapted for enclosure and material attenuation testing.
- MIL-STD-285, VG-Standard - military/industrial test methods used by specialized laboratories for some fabrics.
- Full-spectrum measurement 1 MHz - 40 GHz - used for LBK100 series to demonstrate performance across cellular, Wi-Fi and microwave bands.
Chemical safety & purity
All fabrics supplied through EMF Clothing Ltd and Leblok brand are produced under strict quality and chemical-safety controls. High-integrity shielding textiles are complex to manufacture, and we do not use low-grade or chemically unstable materials.
All Leblok fabrics and garments are manufactured under ISO 9001-audited processes. Our suppliers are assessed by qualified ISO 9001 Lead Auditors to ensure compliance with international quality standards. Chemical-contamination testing is routinely performed to the following recognised standards:
- EN 16711-1
- ISO 17294-2: 2005
- EN 1483-2007-07
- ISO 1188: 2009-09
Leblok clothing is manufactured in the United Kingdom to ISO 9001 Quality Standards, ensuring full traceability and confirmed material safety.
Care & handling (practical instructions)
- Care for silver EMF shielding fabrics and clothing: Machine wash only at 30°C using Leblok washing powder, as other detergents may reduce shielding performance. Do not dry-clean, hand-wash, tumble-dry, or bleach. Drip dry only. Iron on low.
- When sewing conductive fabrics, use silver thread or anti-corrosive thread for external finishes and avoid high-compression seams that break conductive paths if continuity of shielding is needed.
- For installations using conductive materials, ensure continuity at joins and use our Copper Grounding Tape or our General Grounding Kit where recommended.
Technical FAQ & glossary
- Q: What does “dB” mean for shielding?
- A: Decibel (dB) is a logarithmic ratio. A 50 dB reduction means the field amplitude is reduced by a factor of ~100,000 (very strong attenuation).
- Q: Which fabric should I choose for clothing?
- For wearable garments, only conductive fabrics should be used. Conductivity in the textile creates a continuous or semi-continuous conductive path which provides effective shielding when worn. Our in-house clothing uses the SLine series fabrics (listed on the individual garment product pages) and other purpose-designed conductive textiles such as Silver SuperShield where appropriate. Materials like LBK100 are highly conductive but are engineered for structural/wall installations and are not suitable for apparel due to stiffness, backing, or installation requirements.
- Q: Are these fabrics safe for babies and pregnant women?
- A: Many of our fabrics are tested for textile safety (e.g., EN 16711-1 for Leblok SLine farics). We do not make medical claims; consult product pages and, if in doubt, seek professional medical advice.
- Q: Can I ground a garment?
- A: Leblok garments can be grounded, while grounding garments is generally unnecessary and uncommon. Grounding is primarily relevant for structural shielding installations, such as walls, panels or large-area applications using materials like LBK100 or Silver SuperShield.
- Q: Are Leblok and EMF Clothing fabrics safe to use in bedrooms or sleep environments?
- Yes. Our fabrics and canopies are manufactured without toxic finishes and are tested to ensure the absence of harmful residues. They can be safely used for sleeping without releasing odours, vapours, or particulates.
- Q: Do your clothing contain nano-silver?
- No.
- Q: Why do your products cost more than some alternatives?
- High-grade shielding textiles require controlled manufacturing, verified purity, and consistent shielding behaviour. We do not use low-cost shortcuts that compromise chemical safety or performance. All materials undergo ISO-audited production and chemical-contamination testing.