WASHINGTON—Eliminating injuries and fatalities in tower work is the aim of a new partnership of OSHA, NATE and the FCC.

 “The goal of the three-year partnership is to eliminate worker injuries and fatalities while performing wireless and telecommunications, tower erection and maintenance operations,” they said in an announcement.

“The partnership will address some of the industry’s frequently encountered hazards, including falls from height, electric, falling objects, tower collapses and inclement weather.”

The agreement was signed in an online ceremony involving officials of the Occupational Safety and Health Administration, NATE: The Communications Infrastructure Contractors Association and the Federal Communications Commission.

They included Principal Deputy Assistant Secretary of Labor Loren Sweatt, NATE Chairman Jimmy Miller and FCC Chairman Ajit Pai.

Sweatt said demand for wireless communications and broadcast services has increased the need for construction, service and maintenance of towers around the country.

The effort is being done under OSHA’s Strategic Partnership Program.

This story originally appeared on TVT's sister publication Radio World.

COLUMBIA, Md.—By his own admission, Richard Tell has climbed lots of broadcast towers, gotten himself exposed to some really intense radio frequency fields, suffered RF burns and on occasion has even (accidentally) burned out “some fancy test equipment,” but “never to my knowledge experienced a health effect from my work in RF fields, except for the burns.”

Tell, now 75, and an industry expert in the effects of RF radiation on the human body, shared some of his experiences and deep knowledge of the subject at an RF safety seminar put together by the Washington, D.C., and Baltimore SBE chapters under the auspices of Fred Williard, an officer of the D.C. chapter, and hosted by Rohde & Schwarz at their North American headquarters and training facility.

Tell’s presentation—“Staying Safe In RF Fields”—was tailored to provide broadcast engineering personnel and others involved in RF work with the knowledge they need to stay safe and prevent injury. The free day-long course attracted transmitter operators, station and broadcast group personnel, consulting engineers, network employees, two-way radio service technicians, government and military employees, amateur radio operators and even a SiriusXM satellite radio representative from as far away as New York and Richmond, Va.

Tell, an IEEE Life Fellow and chair of RF safety-related committees within IEEE, spent some 20 years with the federal government, working for the Center for Devices and Radiological Health, and later serving as chief of U.S. Environmental Protection Agency’s Electromagnetics Branch, and providing technical support to the FCC when that agency was setting new rules for human exposure to RF fields.

His 52-year-long career not only includes laboratory work and computer modeling, but also plenty of “hands-on” experience—including purposefully subjecting himself to RF currents—that makes him uniquely qualified to impart knowledge and field inquiries into this sometimes rather gray area of radio and TV station operations.

WHERE THE DANGER LIES

In setting the stage for the “practical” portion of his presentation, Tell provided a definition of “MPE,” or Maximum Permissible Exposure (“according to the FCC, this is the amount of field exposure outside the body that is considered safe”), and “SAR,” or Specific Absorption Rate (“the rate at which RF is absorbed in the body, and which is the basis for our safety standards”).

He also distinguished between ionizing and non-ionizing radiation—terms that confuse many lay people and even some professionals. Ionizing radiation occurs when there’s sufficient energy to remove electrons from an atom typically associated with very penetrating radiations, such as x-ray and gamma; non-ionizing refers to any other type of electromagnetic radiation, including the radio frequency spectrum.

“Radio waves do not have sufficient energy to ionize atoms,” said Tell, assuring course attendees that this was not something they had to worry about. “RF fields are not the same as ionizing radiation. They cannot ionize tissue, and unlike ionizing radiation, the biological effects are not cumulative.”

Tell explained that aside from burns suffered from contacting RF-energized conductors, the greatest effect of radio waves on living organisms was heating of tissues, noting that 60 years of research on the effects of RF exposure has established, among other things, that when RF levels fall below a certain threshold, there is no measurable effect on human bodies. Such research has also established a useful “threshold” for what constitutes an excessive RF level.

“The most sensitive and reliable indicator of an established and potentially adverse biological effect of RF radiation exposure has been behavioral disruption of a learned task in laboratory animals,” said Tell. “Their performance ‘slacks off’ because they are ‘warming up’ and less inclined to do what they were trained to do.”

He noted that the threshold for such behavior modification began at a SAR of about 4W per kilogram of body weight, and that this exposure level had been extrapolated to humans and adopted by the FCC in its regulations limiting exposure. Tell stated that a safety factor of 10 is used to constitute what is considered “safe,” with 50 times less exposure being “safer than safe.”

Tell said that in calculating what a “0.4W/kg safe” exposure would be for a 180-pound individual, it amounts to 33W distributed within the tissues. He noted that the normal metabolic rate for humans at rest is about 105W.

“When RF energy is delivered to a lossy material such as body tissue, it produces heating of those tissues,” he said. “Elimination of heating of the body is the primary objective of most safety regulations today.”

Tell observed that the effects of RF on the body are not uniform, with some areas being heated more than others, and that this heating is frequency-dependent, as humans resonate at around 65 MHz.

“FCC exposure limits are based on limiting the rate at which RF energy is absorbed in terms of watts per kilogram of body mass so that you don’t warm up,” said Tell. “A hazardous level of exposure is reached when you begin to warm up from the RF energy impinging on your body.

“The ‘take-home’ here is that if you feel warmer than you suspect would be normal, back off and ensure that your exposure is within the accepted limits.”

PROTECTIVE MEASURES

Tell noted that portable “clip-on” RF monitors, while not necessarily precise indicators, do provide “early warning” information that is useful in flagging what may lead to excessive exposure in RF environments. He also provided some tips for proper use of such monitoring devices, as well as suggestions for mitigating one’s exposure.

“Always wear an RF monitor on the front of your shirt; it should face the antennas generating the radiation you’ll be exposed to,” said Tell. “The difference between front and back can amount to a factor of 16 at 100 MHz. If the monitor sounds only occasionally that’s not a problem. If it’s steady, then it’s time to get out of the area.

“If you have to work close to a high-power antenna, use a personal monitor to determine if the area is below the exposure level; if not, the transmitter must be shut down and locked/tagged out, especially if it’s remotely operated. Take the lockout key with you until all work is completed and the system can be returned to normal operation.”

Other tips include staying behind directional antennas when doing tower work and exercising care when working around non-directional radiators.

“You cannot hide behind an omnidirectional antenna like you can a dish, a Yagi or a panel antenna,” Tell said.

He observed that there were some cases where broadcast operations could not be interrupted and doing work around such transmission sites called for operating with reduced power or wearing a protective body suit and hood designed to attenuate RF exposure to the body.

“Such a suit greatly reduces RF exposure,” said Tell. “But always remember that the suit does not make you into Superman.”

A year ago, the National Association of Broadcasters released a video explaining the implications of the channel repack that nearly 1,000 U.S. TV broadcasters are undergoing after the spectrum auctions. The video was designed to inform the public about a complex, dangerous project and how difficult it would be to complete within the 39 months provided by the FCC. In addition to the financial burdens, it emphasized the technical and logistical challenges faced by tower companies.

“There’s no easy template for this work,” a spokesman in the video said. “It’s hard, expensive and dangerous. There are only a handful of companies in America that can do it safely, and there are nearly 1,000 stations to be moved. Unfortunately the math doesn’t add up. Stations are being forced to move without the time and money to do it successfully.”

We are now seeing some potentially tragic results that could come with a deadline that many warned was unreasonable. Last month, Steve Lemay, owner of a Washington-based tower company was killed and three of his crew members were injured when the 1,980-foot tower for Ozarks Public Television station KOZK-TV in Fordland, Mo., collapsed. TV Technology extends our condolences to Lemay’s family and colleagues over this terrible accident.

[Read: Missouri TV Tower Collapses]

Lemay was working on a $3.4 million project to repack KOZK’s channel from 23 to 16. Lemay and his crew were only 100 feet up the tower, attempting to reinforce the structure when the accident occurred. At press time, the station has returned to cable and satellite and is broadcasting on a limited temporary site.

Lemay is the fourth tower worker to lose his life working on a broadcast tower since channel repack work commenced a year ago. In September, three members of a tower crew lost their lives while working on a 1,250-foot TV tower in Miami Gardens, Fla. It has since been confirmed that both the Miami Gardens and Fordland accidents were a result of work done on the repack. To put this into perspective, there were eight tower deaths in 2017 (three which resulted from repack work), and two so far in 2018 (one from repack work), while in 2016, there were seven overall, according to wirelessestimator.com.

Lemay was considered a consummate professional by his peers and had 25 years’ experience in the tower business; the accident is under investigation so we don’t yet know what was the cause. However, what we do know is that despite tower crews taking all the necessary safety precautions, four deaths have occurred in less than a year due to this work and it may be time for the FCC to reconsider its timeline. We may never be able to say directly that a rushed repack schedule played a role in these tragedies; but any responsible observer could conclude that it’s possible — and that taking more time in this process in the interest of safety is the prudent course. Although some funding has been added to the repack budget earlier this year, the commission should also look into extending the deadline to allow for more flexibility in scheduling tower work before more workers get injured or lose their lives.

“The concern a lot of people have about the repack is that the timeframe is based on everything going right,” Iowa Public Television Director of Engineering and TV Technology contributor Bill Hayes told Current. “The fact is, there are so few crews that are capable of doing this work safely and they’re going to be stretched thin. Something has to give and the hope is that what’s going to give is the timeline.”

Hayes added that without extensions to the schedule, “you can be gambling at best with the reliability of your station’s service, and at worst you’re gambling with people’s lives.”

We couldn’t agree more. OSHA ranks tower work as “the most dangerous job in America.” It’s up to the FCC to consider that fact and reevaluate its repack deadlines.

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WATERTOWN, S.D.—The American National Standards Institute and American Society of Safety Engineers have finalized the A10.48-2016 Standard on tower safety, the National Association of Tower Erectors announced in a press release. Officially titled A10.48 Standard – Criteria for Safety Practices with the Construction, Demolition, Modification and Maintenance of Communication Structures, the ANSI/ASSE standard encompasses the entire tower, construction, service and maintenance industry, and is being described as "the most comprehensive tower construction and use standard ever developed," according to NATE Executive Director Todd Schlekeway.

The new standard establishes minimum criteria for safe work practices and training for personnel performing work on communication structures, including antenna and antenna supporting structures. Other areas of construction addressed in the standard include pre-job planning; job site conditions; fall protection; radio frequency/electromagnetic energy; base mounted hoists used for overhead material lifting and personnel lifting; personnel lifting accessories and process; rigging; gin poles and other lifting devices; structural construction loading considerations; training program; capstan hoist; demolition; and helicopters used for lifting loads.

Kathy Stieler of Electronics Research Inc. was a member of NATE’s A10.48 subcommittee that worked with ASNI/ASSE to develop the new standard. “The A10.48 Standard will provide the ultimate road map for companies and workers to adhere to in order to raise the bar on safety and quality in the industry,” she said. “This transformative standard will fill a huge void that currently exists right now in the industry.”

Schlekeway also believes that this new standard is coming out at just the right time. "The timing of the standard's completion is significant as well as it comes prior to the Broadcast Repacking work that will be done in the aftermath of the 600 MHz Incentive Auction," he said. "The timing of this new standard is also great as it will be a go to resource for contractors and subcontractors involved in the FirstNet Public Safety Broadband Network deployment in the near future."

Representatives from NATE, ASSE and the Telecommunications Industry Association will be providing information and educational opportunities on the A10.48 standard in the coming weeks. NATE says it will also provide an update on how to purchase the standard when it is officially published.