Kathleen Davis, Associate Editor
At the American Society of Civil Engineers’ 2002 Electrical Transmission Conference in Omaha last month, speaker Edgar Turcotte of Tadros Associates LLC, a structural engineering and consulting firm located in Omaha, stated that “assuming logistical hurdles can be overcome, co-location of telecom equipment with transmission is nothing to be feared.”
Where we started
Turcotte began his presentation by tracing the history of the attempts to co-locate the two industries. Reaching back into the 1980s, Turcotte pointed out that wireless communication was relatively unknown, and that zoning officials at the time were unfamiliar with the telecom equipment required. In fact, in those days, very few individuals had any idea of the scope of equipment telecom would need.
With the drastic rise in wireless communication in the early 1990s, communities became all too familiar with that telecom equipment, and they became concerned about the number of towers popping up. However, these aesthetic concerns were still a relatively minor reason to look into co-location, for the cost of new telecom sites were relatively cheap (approximately $150,000, according to Turcotte’s presentation).
By the approach of the millennium, most American communities were served by at least one provider, leading to more vocal concerns about the number of towers on the horizon.
“It was at this time that the public finally says ‘enough,'” Turcotte stated. “It’s time to look into co-location.”
“In fact, today new telecom structures are a last resort in most communities,” he added.
And aesthetics is not the only factor in that decision. Since the telecom bust, money for new sites is fairly tight and that $150,000 that looked like pocket change just a decade ago is a huge investment to the telecoms of today.
Turcotte gave the example of one company’s work in one small Nebraska town where they were required to prove that every single existing tower wouldn’t work for their purposes before they could put up a new tower.
“Therefore, for many reasons, one of the most attractive places to put telecom equipment is on transmission towers,” he stated.
Where we’re going
Even with all the positives of co-location, Turcotte warned that the system is not without problems: radio frequency attachment heights are limited; utilities resist granting wireless providers 24-hour access to sites, making it difficult to provider complete customer service to wireless consumers; and, of course, the hazards of having telecom employees working on an energized structure “are not trivial,” Turcotte stated.
One of the largest questions on the engineering side of the equation is whether the applicable codes for each industry are compatible enough to allow for a single structure to cover both requirements. The standard telecom code, TIA/EIA-222-F(G), is limited to steel structures, has no specific ice requirement and contains a 50-year recurrence to determine wind code. When compared with standard power transmission structure codes, specifically NESC-2002 and ASCE 74, the telecom code is actually quite compatible.
Turcotte gave the specific example of a four-sided steel lattice tower located in Omaha with an antennae mounted at 130 feet. In a comparative analysis of all three codes on that structure, the TIA standard gave him 783 pounds of load. The NESC 2002 gave 758 pounds of load, and the ASCE 74 code gave 818 pounds of load. So, overall, the telecom code was within four percent of standards commonly used by utilities, making co-location a viable solution.
“NESC or ASCE-74 will not significantly punish telecom clients,” Turcotte concluded.
