What is Radiofrequency (RF) Compliance?
Radiofrequency energy, or RFE, is regulated by the Federal Communications Commission (FCC), and the Occupational Safety and Health Administration, (OSHA), and has been deemed a physical hazard. In March of 2013, the FCC voted for an advanced review on various rules pertaining to implementation of National Environmental Protection Act, (NEPA), requirements in relation to RFE from radio transmission sites. This review included several issues pertaining to technical and semantic issues implementing NEPA updated and revised procedures from the previous 2003 proposals, the FCC also requested comments on whether or not its RF exposure limits and policies needed reassessment.
Antenna site owners and operators need to take into consideration their workers exposure as well as the general public’s health considering their exposure to RFE. The most stringent area of the spectrum is frequencies ranging from 30 to 300 megahertz, at these frequencies the size of the wave closely resemble that of the human body which at that point acts like an antenna.
The Office of Engineering and Technology, (OET) bulletin 65 “Evaluating Compliance with FCC guidelines for Human Exposure to Radio Frequency Electromagnetic Fields” provides assistance in determining whether proposed and existing transmitting facilities, operations and devices comply with limits for human exposure to RF fields. This standard also provides examples of, and procedures on how to perform evaluations in these fields. Exposure to the general public as well as workers on towers and the exposure value in the form of percentage of the standard also have to be addressed. (Figure 1)
A guidelines and exposure limits by frequency chart, and a complete breakdown of exact exposure in milliwatts, (mW) per centimeter squared can be found on the FCC’s website. The controlled standard for or MPE, which is put in place for qualified or competent workers who can control their exposure and mitigate risks involved with RFE, due to briefings and specialized training, is higher than the uncontrolled standard which is for the general public and workers which may be transient, such as window washers or HVAC technicians, who do not know of the potential risks involved, and have not been properly trained in regards to the risks with RFE. The general public and transient worker, or uncontrolled, exposure limit is 20 percent, which is also OSHA’S action limit, of the controlled standard. As set in the American National Safety Institute, (ANSI), and the Institute of Electrical and Electronics Engineers, (IEEE), their C95.1 standard allows only 100 milliamps, (mA), of induced current in any working environment.
Best safe practices or sound engineering practices are acceptable procedures and methods for attaining compliance. Bulletin 65 from the OET does not establish mandatory procedures and practices; guidelines and suggestions for maintaining and evaluating compliance for carriers can be found here. Individual site plans and best safe practices are required for all existing and new sites, which can be provided by third party RF safety consulting firms. If an area does not fall into compliance with the FCC MPE guidelines, the licensee can be fined and corrective actions must be taken if they are emitting over 5% of their allocated MPE. Also if a tenant, antenna owner, building owner, the property managing entity or controlling company of a collocated antenna array is above the 5% ruling they can also be fined and forced to take corrective actions. Documentation of compliance may be requested by federal, state and local governing entities concerning cellular, WIFI, paging systems and BDA/DAS systems. If there is any of these areas that fall outside the parameters set by the standards, abating is required and may result in being fined as well.
Bringing a site into compliance can be performed by a series of steps involving; site evaluation, MPE
measurements, modeling, analysis, and a site safety plan certified by a qualified or competent person. This will allow for the site owner and carrier, building owner and the property managers to ensure that they have a safe site for workers and the general public in all areas in and around the site of these antennas. Antenna towers that have RF potential at the base, such as AM broadcast towers, must have a locked fence enclosure and signage to be compliant according to 47 CFR § 73.49. Barriers, signage, locked doors and man proof ladders are ways to control access to areas that are above the controlled and uncontrolled limit of the MPE. Signage at antenna or tower sights should state the hazard before entry into the actual affected area. The individual site safety plans must be maintained on site or with the property managers or controlling entity, as well as a list of all hazardous material, as stated in the 29 CFR 1910.1200 standard, they may encounter on the site, and a list of contacts in the event of an emergency such as fire/explosion, extreme over exposure, slip, trips and falls.
These site plans should be reviewed and understood by all personnel accessing the site and training may be required to remain compliant and for the safety of the workers, including a lock out/tag out program, so workers can work safely around antennas and perform periodic maintenance as required. Powering down of these antenna sites may be required as stated in the 29 CFR 1910.147, and in the licensees FCC broadcast forms 351A, and license form 351B, to mitigate the risk of possible induced or contact current burns or shocks. It should also state areas of high RFE and areas that may need to be avoided or entered only by trained personnel with personal RF monitors or proper personal protective equipment such as RF suites. Site surveys for towers must be maintained and accessible at all tower installations.
Over exposure to RFE takes on the shape as if getting sick, much like flu symptoms. The individual exposed may experience dizziness or vertigo, confusion, sweating, headaches and nausea, depending on frequency and your bodies relation it can also affect implanted medical devises and heat jewelry. RFE exposure is non-accumulative, therefore in the event of over exposure to RFE, a worker should immediately be removed from the area and closely observed, and once removed from the area the body will cool itself through natural processes.
Requirements of personnel working at broadcast site should be known through-out the operating or controlling company and at a minimum; be trained by an authorized and qualified person as defined in OSHA’s 1926.32 standard, authorized to enter the site facility, obey all posted signage and should assume that all antennas are active until power down or lock out/tag out has been communicated and verified with the controlling entity, never stop or work in front of antenna array, were a personal protective monitor, these monitors have precedence over any and all signage, required fall protection 100% when above six feet, and work in pairs as in a qualified person and competent climber. Any further questions can be answered on the FCC and OSHA websites, or on RSI’s frequently asked questions page at www.rsicorp.com. Contact RSI Corporation if you need assistance in understanding Radiofrequency (RF) regulatory compliance – Contact – RSI