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What is an RF Hazard Assessment?

An RF hazard assessment is a scientific approach to determine ambient RF levels at a given site.

Who needs an RF Hazard Assessment? FCC licensees, building managers, site managers, construction companies, anyone who has people exposed to Radio Frequency Emissions.

An RF hazard assessment at an antenna site is very involved and requires the person performing the assessment to be trained, competent, and qualified to perform the assessment. The assessor must have some basic knowledge of the site prior to showing up on the site so that the proper equipment is taken to the site. Some equipment may have a limited frequency range, while some may be very directional. Most RF probes are for use at communication sites are field dependant as well. At sites with transmitters below 300 MHz both the magnetic and the electric field must be measured due to the fact that either one could be dominant. In addition the site must be assessed for induced and contact current hazards. The best equipment on the market today can have as much as 4 db of error. These items can in some cases be addressed and mitigated with proper training. Some of the other equipment could have as much as 30 db of error in complicated environments. As discussed earlier a personal protection monitor can be used for a limited hazard assessment. Prior to this being done the site must go through an extensive hazard assessment with the proper measurement equipment that will show actual RF levels at the site.

Calibrated RF Meter Calibrated E-Field Probe Calibrated H-Field Probe Calibrated Personal Protection Monitor Digital Camera Film Camera Sling Psychrometer GPS Tape measures 2 Meter “Story Pole”

There are several reasons to perform hazard assessments at telecommunications sites. The basic one is to ensure safe conditions for employees or the general public who may be at the site. Another reason would be to have the correct information to be used for training or zoning type meetings. And still another is to insure compliance with regulations. Compliance with regulations may not always be as easy as it sounds. Being compliant with FCC exposure criteria may not mean that a site is compliant with OSHA and vice versa. The assessor must be familiar with the regulations as well as the intent and interpretations of the regulations.

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A hazard assessment done correctly can also help to identify exposures from off-site emitters as well. This could be from an RF source or from a chemical. A proper assessment can also lead to correct documentation of the site, Who is there, at what level, with what type of equipment etc. For site managers this can lead to increased revenue or at least corrected documentation of the site. The assessment should also include what type of signage is at the site and where it is located.

Finally the assessment must be repeatable. The methods and procedures must be able to stand the scrutiny of a zoning board or city council as well as the possible scrutiny of a legal representative. RSI uses industry standard procedures for environmental assessments, which have been able to stand the test of time.

A hazard assessment must include documentation    of the assessment!

At RSI we use a standard format for our assessment reports, which includes the following items:

An abstract that tells in the first paragraph if the site is compliant with the FCC regulations. Descriptions of the methods and instruments used Description of the site Maps showing where the site is Photographs of the site Site renderings, which show in general how the site is laid out and the location and type of antenna’s The RF readings with the inherent deviation factors A laminated, color-coded rendering to be used at the site showing RF levels and hot spots according to the standards of the FCC Equipment certifications Recommendations for signage (if needed) Recommendations for training (if needed) Recommendations for mitigating RF hazards (if needed) Recommendations for mitigating other hazards (if needed) All assessments include a site security review

RSI has performed thousands of assessments at various types of sites including:

Towers at ground level Towers vertically Roof-tops Mountain-tops Industrial sites Hospitals International Airports 911 call centers In-building assessments Government Installations

Some interesting items which have been found at hazard assessments performed by RSI:

Re-radiating tower guy wires Crane cables causing shocks and burns Re-radiating metal objects Alligators on site Leaks in coax and wave-guides Deteriorated guy anchors Hot-spots at 50 times above the standards Fall protection issues Automatic fire extinguishers tripped due to RF Interference with elevators due to RF Industrial sites which, could interfere with pacemakers

The methods and procedures RSI uses can meet all the criteria outlined above as well as others that individual clients may have.

*Please Note: RSI is a University based safety service organization. Our reports have been reviewed by and are on record with the FCC and other government agencies. This report is a safety and NEPA compliance report as required by the agencies, and is not intended to be an engineering document. An engineering report would not reflect the various safety issues that are encountered at many sites. RSI uses competent and qualified safety professionals and OSHA authorized trainers to review and develop programs. This document reflects this expertise.
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Graphical Assessment Examples: (click to see a larger pdf version)
Site Layout	Site Readings	Equipment Room	Colormap