Resistance to unsightly towers has prompted many wireless carriers to site their antennas on existing
structures such as buildings and water towers to reduce the visual impact of their equipment.
That solution may
soothe tensions at local zoning commissions, but it also may be creating a headache for carriers-one that is becoming
more urgent each day.
In 1997, the Federal Communications Commission finished rules requiring wireless carriers
to comply with maximum permissible exposure (MPE) limits at their sites. The rules became effective in October 1997,
and wireless carriers have until September 2000 to bring all of their sites into compliance. Compliance also is triggered
when licenses are renewed and when changes are made to a site.
The problem is more urgent for paging carriers,
which have some of the biggest problems with MPE because of the omnidirectional nature of their antennas. Most
paging licenses must be renewed April 1.
The official word at the FCC is that carriers’ work toward compliance is
progressing, but some vendors tell a different story.
“What we are seeing out in the marketplace is that not a
whole lot is being done by the carriers,” said Mike Hofe, vice president and chief technical officer at Clear
Communications Group Inc., which is providing services to help carriers comply with the rules.
“There is a
lot of misinformation out there,” said Hofe. “A lot of carriers believe they are categorically excluded from
complying because of height. They may be categorically excluded from doing a full-blown environmental assessment,
but they are not excluded from MPE rules.”
Problems
Traditional wireless towers, despite their battered
image, have at least one redeeming quality. In most cases, antennas are placed so high on the tower that the general
public would not be at risk of overexposure under the FCC limits.
“Towers are nice because only people in
the industry are climbing towers and they should know the risks,” said Rich Biby, president of engineering
services at SiteSafe L.L.C., another firm working with carriers on MPE compliance issues. “It is much easier to
identify and control who is going on a tower.”
Rooftops and other existing structures are a different story.
Often several carriers have equipment on a rooftop, which increases the likelihood of reaching MPE limits, and the
environment is much more difficult to control. Any carrier that contributes 5 percent or more to MPE at a site is
responsible to bring the site into compliance.
In addition to personnel accessing the rooftop to maintain carrier
equipment, other people need access to rooftops as well, such as heating and air-conditioning workers, roofers and
window washers. Those workers may not be aware of the dangers of overexposure to RF, and under the FCC rules, it is
the carrier’s responsibility to take steps to protect them.
Circumstance and technology have helped some carriers
with compliance.
“Because of things like vandalism, right from the original build we have put antennas where
they are not accessible,” said Robert Langston, a member of the technical staff at Bell Atlantic Mobile. “So
by default, those sites are not at issue.
“In addition, a lot of our sites are being powered down because of
digital rollout,” said Langston, who noted the company has spent three years working to control exposure at its
sites.
Other carriers have not been as proactive, in part because of a lack of awareness of the rules and what they
mean, say those familiar with the issue. Problems coordinating the various carriers with equipment at each site also is
proving to be a problem.
Cooperation among carriers isn’t necessarily what is difficult, said Langston. “It’s
more a question of our people getting to the right person at other companies.”
Keeping up with sites that are
constantly changing because of new transmitters and other events proves to be a problem as well.
“Sometimes
our technicians come back and say a there is a new antenna at a site,” said Langston. “It’s a tough thing to
manage. If we relied on site managers to tell us when there is a change, we’d never know.”
Solutions
The
first step carriers need to take to bring their sites into compliance is to perform an assessment of each site. Companies
like SiteSafe and Clear Communications provide software modeling and field-testing services that can help determine
exposure levels at sites.
“The entire concept is to identify unsafe areas and provide a mechanism for people to
go into those areas,” said SiteSafe’s Biby.
Once unsafe areas are identified, carriers have a variety of options
to limit potential exposure to RF energy.
One solution is to re-engineer the site by increasing the height of antennas
or moving them away from equipment that often needs to be accessed.
Carriers also can attempt to control the area
by putting up fences or signs to keep people at a safe distance from antennas. They also can create exposure maps that
delineate safe areas and unsafe areas.
RF safety programs that define procedures for working in areas where RF
exposure is likely also are critical, say experts.
A final solution is to require anyone accessing the site to wear
personal monitoring equipment that signals when they may be close to their maximum exposure. Training on such
personal monitors is key.
“You don’t want to scare people, so you need to give them a couple of hours of
background on the health effects,” said Biby. “You don’t want to tell them ‘Your head could explode, but
wear this and you’ll be fine.'”
“The operative thing is personnel protection-not just your own, but
everyone’s,” said Richard Strickland, director of business development for Instrument Products at Narda
Microwave-East, which supplies personal monitoring devices. “We used to say it was an occupational problem,
but that is no longer the case because of rooftops.”
Strickland said the company increasingly receives inquiries
from companies outside the wireless industry that want to know how to protect their employees from overexposure to
RF energy.
Jerrad P. Jasper, vice president of MasTec Wireless Services, a general contractor in the
telecommunications industry, said the company’s employees do not use personal monitors, preferring instead to avoid
exposure whenever possible. The company does, however, train all field employees and subcontractors to be aware of
the dangers of RF energy, and when RF exposure cannot be limited by suspending transmissions, only employees
trained on personal protection equipment are allowed to access the site, he said.
Workers accessing sites should be
trained to know the physical signs of exposure, say experts. Symptoms such as headaches, nausea and dizziness are
signs of overexposure.
“A combination of these things need to happen,” said Biby. “No one
solution is going to work.”
The countdown
Clear Communications’ Hofe cautions carriers that think using
software modeling will solve their problems may be getting a false sense of security.
“Computer models are
only as good as the assumptions you make,” said Hofe. “You need field technicians that understand
RF.
“There aren’t enough qualified companies out there that understand field testing,” continued Hofe.
“I’m afraid people are going to wait until the 12th hour, and they really need to be proactive now before the
hammer falls.
“There’s definitely a sense of urgency,” said Hofe. “Some companies may have 30
or 40 or even 10,000 sites, and compliance work can’t be done overnight.”
