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May 2, 2023
Transmission Towers and Galvanic Protection: Everything You Need to Know
Written by: Sam Steele
Transmission Towers and Galvanic Corrosion: Everything You Need to Know
A transmission tower is a large, metal structure set up for the purpose of transmitting and receiving power, radio, telecommunication, electrical, television, and other electromagnetic signals. The towers can also be identified as electric towers, broadcast towers, or cellular phone towers — depending on the purpose they serve. If you look around your area you will see that these towers are, well, everywhere.
Whatever purpose they are designed for, they have a few things in common. Every transmission tower features a sound structure with a lattice pole construction that is designed to withstand tough weather conditions without damage for as long as possible. Anything made from metal, which transmission towers are, can’t stay in pristine condition forever though. Metal eventually falls prey to galvanic corrosion. This is a big problem because these towers are often very large, very old, and very important.
How Big Are These Towers?
When we say these towers are large, we mean it! Cell phone and wireless data towers are usually about 200 to 300 feet. Broadcast towers are significantly taller. According to Federal Communications Commission records, there are actually 16 towers in the country that reach 2,000 feet and above, with dozens more only a few feet from the 2,000 mark. Federal Aviation Administration regulations prohibit building above that limit, and only three currently standing towers have exceptions to the rule.
If you’re thinking it’s not a good idea to let a tower hundreds or even thousands of feet tall fall victim to rust and corrosion, you’re absolutely right. Depending on where exactly the tower is, this could happen sooner rather than later.
How the Surrounding Area Effects Galvanic Corrosion
How quickly a metal tower begins to corrode is heavily dependent on the geographical area it is located in. We see especially corrosive environments in areas like Florida and Texas. The warmer it is, the easier it is for chemical reactions and corrosion to occur. Corrosion to the point of degradation happens quickly in THE hot, moist environment southern beaches are so well known for. This doesn’t even take into the hurricanes and other ferocious weather outdoor metal structures face in these areas.
That’s not to say towers in northern climates face no threat of corrosion. In fact, some of the most catastrophic tower collapses in history have been in northern states, often due (at least in part) to ice. If a tower is left to rust and corrode, it grows weaker and weaker. Then, winter comes along and the added load from the freezing ice will make it collapse. Any type of corrosion left unmitigated makes the tower more prone to breakage. If it’s structurally compromised in any way, the freeze and thaw cycle that occurs in northern states lends itself to even more damage.
It isn’t the very top of the tower that’s the biggest concern, which may come as a surprise. Any piece of the tower that is on the ground will be in contact with more moisture, due to grass, dirt, dew, rain puddles, and other climate factors. Anything in contact with moisture corrodes and doesn’t last as long.
The bottom line is no matter where a tower is located, regular inspections and maintenance are essential to avoid dangerous breaks. Hot, cold, humid, wet, snowy, or icy — metal will begin to rust in an outdoor environment.
The Importance of Regular Inspection
The structure of a tower must be regularly inspected for damage and maintenance issues. The Telecommunications Industry Association produced the Structural Standard for Antenna Supporting Structures and Antennas (TIA-222-G is the current revision). In addition to procedure, this gives a recommended schedule for tower inspections. This is typically every three years for a guyed tower and five years for a self-support tower, at a minimum. The recommendation is once a year for coastal areas that are subject to corrosive salt air and high winds.
The structural inspection at height must include a visual assessment of tower legs, cross members, climbing facilities, guy point shackles, tension arms, platforms, and walkways, plus the nuts and bolts that hold it all together.
The key to tower maintenance is the inspection of the mechanical structure itself. Specially-trained technicians must look closely for any hint of corrosion or damage to its structural integrity. The condition of the paint on a tower is an indication of the level and quality of the maintenance provided to the structure. Simply dipping the metal in a galvanization process before it is assembled is not enough. Once the paint on the tower begins to flake off, it takes galvanized undercoat with it. This exposes the vulnerable steel underneath to the corrosive effects of moisture. The wetter and saltier the air, the more quickly this will happen — hence the requirement for more routine inspections in coastal regions. For a hollow leg tower, allowing corrosion to take hold can shorten the lifespan of the structure by more than half.
Retrofitting Towers for 5G
5G towers are essentially the same as 4G towers or 3G towers — except for the newer and more capable equipment placed on the tower. All across the country, more and more existing towers need updates to fit 5G transmitters. After all, the large towers are already there, so why build a new one when you can update an existing one? This is sound logic for sure, but ignores the fact that in order to fasten new components onto a tower you are doing a bit of damage to the paint and metal. It is necessary to do protective paint touch ups to the tower at this time in order to keep it from corroding.
That’s not to say there are no new towers, of course. CTIA, which represents the big 5G network operators like AT&T and Verizon, counted a total of 419,000 cell towers across the US at the end of 2021. Just a year later, in 2022, that number was closer to 525,000. Clearly, there is an explosion of wireless technology and quite a lot of towers are needed to accommodate this. The components needed to help facilitate wireless network growth need corrosion protection, because they’re in exposed areas.
Galvanic corrosion is a problem all across the country for both aging and new transmission towers, this much we know. The question is — what is the right solution?
ZRC Cold Galvanizing Compound Eliminates Galvanic Corrosion
ZRC’s products are equivalent to hot-dip galvanizing, manufactured with the highest purity ASTM D520 Type III zinc dust, and meet VOC standards in all fifty states. As well, our products passed a grueling ten-year subtropical exposure test and always exceed ASTM A780 standards for hot-dip galvanic repair. With our cold galvanizing compound, there is no need to dissemble a tower in order to ensure it won’t rust or corrode. The ease of application and performance in the most intense environments cannot be beat.
You know you need to keep your transmission towers in top condition, but you certainly don’t want to habitually service it.
It costs money to pay someone to climb up a tower — quite a bit of money. Kevin Schmidt recently became famous across the internet for climbing 1,500 feet in the air to change a light bulb, and making $20,000 every time he does it. Why? To put it plainly, very few other people are willing to do it!
For tower maintenance projects, your expense is almost entirely in the labor. This is why it is so important to use a high-quality product that won’t need reapplication within a few months or even a year. Don’t send someone up your tower five times a year for repair when you can send them up once every few years simply by using a superior product the first time around!
Maximize the Lifespan of Your Tower with ZRC
Every year, technology grows and evolves with an increasing reliance on wireless. The components needed to support wireless networks require large towers. It doesn’t matter whether you are building a brand new transmission tower or retrofitting an old one to support the increased data load of a 5G telecommunications network, these telecom projects need ZRC cold galvanizing compounds.
Proper tower maintenance not only helps to maximize the lifespan of the tower, but also helps to lower the ongoing cost of your financial investment. This is a financial investment that many companies are taking right now.
No matter what your transmission tower project is, labor cost is incredibly intensive to service these structures. You want to use a product that is shown to last, and we have the data to prove that our cold galvanizing compounds can do exactly that. Simply put, our product is the best of the best! With flexible application formats, our product sets the industry standard for combating corrosion and providing true galvanic protection. We are pioneers of a quality solution that lasts, and we’ve been doing it for over 70 years.
If you’re interested in learning more about the science behind these claims, download our free ebook about galvanic protection.