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Studies on biological effects of microwave radiation (second report). Investigation of shielding effect of concrete, lauan and glass against microwave radiation

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Ikeda H. · 1966

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Concrete blocks 99% of microwave radiation while wood and glass provide minimal EMF protection.

Plain English Summary

Summary written for general audiences

This 1966 Japanese study tested how well common building materials block microwave radiation at 2450 MHz (the same frequency used in microwave ovens). Researchers found that 10 cm thick concrete blocked 99.2% of radiation, while wood (lauan) only blocked 81%, and glass was largely ineffective at just 51% blocking.

Why This Matters

This early research reveals crucial insights about EMF protection that remain relevant today. The 2450 MHz frequency tested is identical to what modern microwave ovens use, and similar to WiFi and Bluetooth signals that now permeate our homes and workplaces. The findings demonstrate that concrete provides exceptional shielding (99.2% blocking), while common materials like wood and glass offer minimal protection. What this means for you: the walls in your home provide vastly different levels of EMF protection depending on their construction. Concrete and masonry structures naturally shield you from external wireless signals, while wood-frame houses with large windows allow much more EMF penetration. This explains why EMF levels can vary dramatically between different buildings and rooms.

Exposure Information

Specific exposure levels were not quantified in this study.

Cite This Study
Ikeda H. (1966). Studies on biological effects of microwave radiation (second report). Investigation of shielding effect of concrete, lauan and glass against microwave radiation.
Show BibTeX
@article{studies_on_biological_effects_of_microwave_radiation_second_report_investigation_g6384,
  author = {Ikeda H.},
  title = {Studies on biological effects of microwave radiation (second report). Investigation of shielding effect of concrete, lauan and glass against microwave radiation},
  year = {1966},
  
  
}

Quick Questions About This Study

10 cm thick concrete blocked 99.2% of 2450 MHz microwave radiation, allowing only 0.8% to penetrate. This demonstrates concrete's exceptional effectiveness as natural EMF shielding in buildings.
No, 10 cm thick lauan wood only blocked 81% of 2450 MHz radiation, allowing 19% to pass through. Wood offers significantly less EMF protection compared to concrete or metal materials.
Glass provides poor microwave shielding, blocking only 51% of 2450 MHz radiation even at 0.8 cm thickness. Windows represent weak points in a building's natural EMF protection.
Researchers used 43.4 mW/cm² intensity at 2450 MHz frequency. This high-intensity exposure allowed them to accurately measure how much radiation different building materials could block.
Thicker materials provide better EMF blocking. The study tested concrete at 5 cm and 10 cm thicknesses, with the thicker sections offering superior microwave radiation protection.