Development of Rad Haz suit and RF measuring techniques, SF-013-15-04
Rutkowski A, Christianson C · 1965
A prototype RAD HAZ suit made from silverized nylon provided a minimum of 25 dB attenuation for low-power fields and better than 20 dB for high-power fields, and withstood laundering and open-sea environments without degradation.
Plain English Summary
A prototype RAD HAZ suit was developed through the joint efforts of NSRDF and NAVAPLSCIENLAB to protect naval personnel required to operate in hazardous RF environments on ships and at shore installations. The suit's silverized nylon material withstood laundering, dry cleaning, weathering, abrasion, and open-sea environments without degradation of RF attenuation. The prototype suit provided better than 20 dB attenuation for high-power fields at BMEWS frequency with a power density of 200 mw/sq. cm, and field evaluation showed good performance with no meter deflection or visible arcing.
Why This Matters
The study set out to develop measurement facilities and techniques for RF shielding materials, then apply those to building and field-testing a protective suit. The laboratory microwave source used a 0.25 megawatt modulator energizing a pulse-operated magnetron at X-band frequencies, with a peak power output of 428 KW and a maximum duty cycle of 0.001. Attenuation was measured by comparing power received with and without a fabric sample in place, and samples were moved to various positions within one wavelength of the receiver so that the maximum received power was used to calculate the minimum insertion loss. Resistivity was measured using aluminum bus-bars and a General Radio Impedance Bridge to determine the d.c. resistance of each sample in ohms per square. Among the candidate fabrics, Fabric C provided better than the required 20 dB attenuation, was permeable to air, and showed the least decrease in RF shielding when subjected to cleaning and destructive tests. The prototype suit showed attenuation greater than 30 dB at BMEWS frequency across all areas of the suit, with attenuation varying between 25 and 30 dB at 5.2 Kmc and a minimum of 25 dB at the neck junction of the zipper and velcro closures.
Finding
The silverized nylon "lino" material used in the suit withstood laundering, dry cleaning, weathering, abrasion and open sea environments without degradation of rf attenuation, Properties. 'The. suit provided a minimum of 25db attenuation for low-power fields at 5,.2kme (mininum of 30db at 425Mc) and better than 20db for high-power fields (BMEWS £ frequency, 200mw/sq. cm power density).
In their words
“The silverized nylon "lino" material used in the suit withstood laundering, dry cleaning, weathering, abrasion and open sea environments without degradation of rf attenuation, Properties. 'The. suit provided a minimum of 25db attenuation for low-power fields at 5,.2kme (mininum of 30db at 425Mc) and better than 20db for high-power fields (BMEWS £ frequency, 200mw/sq. cm power density).”
Exposure Details
- Power Density
- 200 mw/cm²
Exposure Context
This study used 200 mw/cm² for radio frequency:
- 20,000Mx above the Building Biology guideline of 0.1 μW/m²
- 333.3Mx above the BioInitiative Report recommendation of 0.0006 μW/cm²
Building Biology guidelines are practitioner-based limits from real-world assessments. BioInitiative Report recommendations are based on peer-reviewed science. Check Your Exposure to compare your own measurements.
Where This Falls on the Concern Scale
Study Details
The objectives of this task are to develop facilities, instrumentation, techniques, procedures and specifications for measurements on RF shielding materials; utilize these measurements in the development of RF protective devices (a RAD HAZ Suit in this phase of the task); and, evaluate the devices in the field, using high-powered RF equipment.
Laboratory microwave power source consisting of a 0.25 megawatt modulator energizing a pulse-operate...
The silverized nylon 'lino' material used in the suit withstood laundering, dry cleaning, weathering...
A prototype RAD HAZ suit has been developed through the joint efforts of NSRDF and NAVAPLSCIENLAB. The suit provided a minimum of 25 db attenuation for low-power laboratory RF fields at 5.2 Kmc (minimum of 30 db at 425 Mc) and better than 20 db for high-power fields (BMEWS frequency, 200 mw/sq. cm power density). Resistance of the material to salt spray and arc-over was poor and is expected to be improved by the use of a coating and an over-garment. The suit was evaluated in field conditions at BMEWS frequency and 5.2 Kmc with power densities up to 100 mw/cm2 and 200 mw/cm2 respectively, showing good performance with no meter deflection or visible arcing in the Ramcor 1200 densiometer tests.
Show BibTeX
@article{development_of_rad_haz_suit_and_rf_measuring_techniques_sf_013_15_04_g4966,
author = {Rutkowski A and Christianson C},
title = {Development of Rad Haz suit and RF measuring techniques, SF-013-15-04},
year = {1965},
}