Giant Flagpoles, 100 to 150 ft: Steel, Cranes, Flag Size and Upkeep for Dealerships, Travel Centers and Campuses

The short answer: once a flagpole goes past about 80 ft, it's steel. A 100 to 150 ft pole is engineered for one address, ships in sections, goes up on a crane in a day once the foundation is in, and flies a very large flag on a winch. The wind and the ground at the address set the shaft, the wall thickness and the foundation, so the address comes before the price.

This article covers the material, height, foundation, crane day, FAA notice, flag size and upkeep.

Why everything over 80 ft is steel

Aluminum makes a very good flagpole: light, rust-free and long-lived. But a taller pole needs a wider, thicker shaft to stay stiff in the wind, and past about 80 ft steel becomes the better material.

America's Dealers and Distributors (ADD) explains it with the numbers on its Mega Poles page: steel is roughly three times as stiff as aluminum, a modulus of about 29,000 ksi against 10,000. At the same width, a steel shaft bends far less in a gust. That's why ADD's range has a gap on purpose. Its aluminum poles, built by Eder, stop at 80 ft, and its steel poles, made in the USA, start at 100 ft and run to 150 ft in 5 ft steps, eleven heights in all.

That gap is common across the trade. A few makers push aluminum higher. Concord American Flagpole, for example, has announced its APEX 100 ft aluminum flagpole. But for most giant poles, the shaft is steel, usually cone tapered and finished with a protective coating.

Where 100 to 150 ft poles go

A pole this tall exists to be seen from a long way off. ADD's page lists the sites where these poles usually go, and the list is worth reading because it shows what the pole is for in each case:

• Car dealerships. The classic home of a giant flag. It marks the lot from the highway before the sign does.
• Truck stops and travel centers. Built to be found from the interstate, miles before the exit.
• RV, boat and equipment dealers. Wide lots on highway frontage with nothing tall around them.
• Shopping centers and outlet malls. A landmark people meet under and give directions by.
• Corporate campuses and headquarters. One flag that reads across the whole campus and from the road in.
• Distribution centers and factories. Long, low buildings where a tall flag is the one thing that stands out.
• Memorials and veterans parks, town gateways and city parks.
• Stadiums, hotels, resorts, colleges, military bases and public buildings.

Picking the height: start from what the flag has to clear

People often start with a number: "We want a 120." The better starting point is the view. Where does someone need to see the flag from, and what's in the way?

ADD's 100 ft steel flagpole page frames it the same way. It asks where the flag has to be seen from, the highway, the main entrance, across the water, and says ADD will tell you which height clears what's in the way. A hundred feet is about ten stories at ten feet a floor. That clears the roofline of nearly every commercial building and most hotels, and puts the flag above the light poles, signs and tree line of a typical highway frontage. It's where dealerships, truck stops, distribution centers and corporate campuses usually start.

A practical check: stand where a driver first sees the property, note the tallest thing between there and the pole location, and add enough height that the whole flag, not just the pole top, clears it.

What the pole itself is

Every steel pole in this range is designed for its site. Still, it helps to see the kind of numbers involved. Acme/Lingo Flagpoles, a family maker in New Jersey, publishes a full table for its BIG JOHN steel flagpoles, which run 90 to 150 ft. Its page offers designs for 100 mph and 130 mph, and lists the butt diameter (the width at the base), weight and number of sections for each:

Three things in that table are worth noticing.

First, the overall length is longer than the height above ground. Part of the pole goes into the foundation, and on a 150 ft pole that's 15 ft of steel below grade.

Second, the wind rating changes the pole a lot. Going from a 100 mph design to a 130 mph design adds roughly a third or more to the weight at most heights. That's the difference between a site inland and a site near the coast, and it's why nobody can quote a giant pole from a height alone.

Third, these poles are several thousand pounds of steel in two to four sections. That's a crane and a long truck, not a crew with a gin pole.

Other makers work in the same territory. Ewing, a Canadian flagpole company, offers custom steel "Gigantic" flagpoles from 100 to 250 ft. Action Flag sells a BigFlag series of giant commercial steel flagpoles from 80 to 200 ft. Each publishes its own range on its own site.

Sized to the wind at the address

On a 30 ft pole, picking the right wind rating is mostly a matter of choosing a series. On a 120 ft pole, the wind speed at the site sets the shaft's width and wall thickness directly. The flag matters even more at this size. A 30 by 60 ft flag is 1,800 square feet of fabric, and when the wind fills it, it pulls on the top of the pole with a force the bare shaft would never see.

ADD's approach is to size every steel pole to its own address rather than quoting one figure for the whole range. Every address in the country has an adopted design wind speed, and two sites twenty miles apart can need different poles. ADD holds the design wind speed for every town it covers, and its quote for a steel pole states the rated wind speed with a flag flying, not just the bare-pole number. Since the flag is the reason the pole exists, that's the rating that matters.

The foundation: as important as the shaft

At this height, the base is a structure in its own right. The pole is a long lever, and almost all the force from the wind on the flag ends up at the point where the pole meets the ground. The foundation has to resist that without rotating, and the soil has to resist the foundation.

ADD's Mega Poles page says it plainly: the foundation is designed for the pole, the flag and the ground it goes in, so ADD asks about soil and access before it prices the job. That's the right order. Soft clay, fill, a high water table or rock near the surface all change the design, and on a giant pole the foundation can be a large share of the cost.

If you're planning one, expect these to come up:

• A soils report. A larger site under development usually has one already. If not, the foundation designer may ask for borings.
• Underground utilities. The hole is big and deep. Know what's under the spot before anyone commits to it.
• Drawings. Many towns will want drawings for a structure this tall. Ask your town early what it needs. ADD provides the drawings a permit application needs.

Crane day

A pole this size ships in sections and is set by crane. Acme/Lingo describes its BIG JOHN as a one-day installation once the foundation is placed, with no welding needed on site. That matches how these jobs generally run: the foundation is done first, and later the truck and the crane arrive, the sections are joined, and the pole is lifted, stood in the foundation and plumbed.

Most of the planning is about getting there. ADD's page asks buyers to tell it about gates, slopes and overhead lines, because site access for the crane and the truck is part of the quote. A long truck has to turn into the site, and the crane needs firm, level ground and room to swing the pole up. Power lines near the pole location are the first thing to check, and sometimes they decide where the pole can go.

A short checklist before crane day:

• [ ] Can a long truck get from the road to the pole location without tight turns?
• [ ] Is there firm, level ground near the foundation for the crane to set up?
• [ ] Are there overhead power or phone lines anywhere in the lift path?
• [ ] Is the foundation fully cured and checked?
• [ ] Is the flag on site and ready, along with the halyard and winch?

Does the FAA need to know?

Sometimes. Federal rules in 14 CFR 77.9 require notice to the FAA for any construction more than 200 ft above ground level. That's taller than any pole in this article. But the same rule also requires notice for anything that rises above an imaginary surface sloping up from nearby airports, for example a slope of 100 to 1 out to 20,000 ft from the nearest runway at an airport whose longest runway is more than 3,200 ft. Under that slope, a structure 10,000 ft from such a runway reaches the limit at roughly 100 ft above the runway's elevation.

In plain terms, a 120 ft pole a few miles from a regional airport may need an FAA notice, and the FAA's answer may include marking or lighting requirements. A pole well away from any airport usually won't. The rule has more detail than this, including heliports and smaller airports, so check it for any site near an airfield, and check it before the foundation goes in, not after.

What size flag does a giant pole fly?

ADD's flag size guide gives the rule of thumb: the flag's length should be about a quarter to a third of the pole's exposed height. Its chart stops at 80 ft, which flies a 20 by 30 ft flag. Carry the same rule up:

The rule is a starting point, not the answer. The pole is engineered for a maximum flag, and that maximum is part of the design. ADD recommends the flag, halyard and winch with the pole, and its quote states the recommended flag size, so the flag and the pole are sized together. Going bigger than the design isn't a small matter on a giant pole. ADD's guide warns that oversizing wears the flag out faster, loads the pole harder, and can void the warranty.

Halyard, winch and cable

A flag that size can't be raised by hand on a rope. Giant poles raise the flag on a winch, usually with the halyard running inside the shaft. ADD's quote for each steel pole names the recommended halyard and winch. Acme/Lingo describes a heavy-duty revolving internal halyard on its BIG JOHN. Some makers offer motorized winches for the largest poles.

An internal halyard keeps the cable out of reach and stops it slapping against the shaft in the wind. ADD's guide to internal and external halyards covers the difference in more detail.

Upkeep: the flag is the part that wears

A coated steel pole on a good foundation is a long-term structure. The flag is not: it's huge, it flies high where the wind is stronger, and its fly end, the edge farthest from the pole, frays first.

A sensible routine for a giant pole:

• [ ] Look at the flag often. Check the fly end for fraying from the ground with binoculars. Catching wear early is cheaper than losing a section of flag.
• [ ] Keep more than one flag. With two or three in rotation, one can be out for repair or cleaning while another flies.
• [ ] Know the weather plan. Decide ahead of time who brings the flag down before a major storm, and how.
• [ ] Have the winch and cable inspected on a schedule set by the maker. A worn cable or a stiff winch gives warning if someone's watching.
• [ ] Check the coating on the shaft and touch up any chips before rust gets a start, especially near the base, where mowers and trimmers hit.
• [ ] Check the lighting. A flag flown at night should be lit, and any light the FAA required has to keep working.

How ADD handles a giant pole

ADD doesn't publish a price for its steel poles, and it explains why on its page: every steel pole is priced to its site. What it does publish is exactly what it needs from you, and what the quote will contain.

To price a 100 to 150 ft pole, ADD asks for:

1. The site address, for the wind and the ground.
2. The height you have in mind, or what the flag has to be seen from.
3. Whether there's a site plan, an architect or a general contractor on the job.
4. Access for a crane and a long truck, and anything overhead.
5. When you need it flying.

Its 150 ft steel flagpole page lists what comes back: the pole sized to the wind at the address, the width at the base and top and the wall thickness, the shaft sections and weight, the foundation design for your soil, the rated wind speed with a flag flying, the recommended flag size, halyard and winch, the finish and lead time, and freight, crane and installation. It comes as one quote for the whole job, from a person who reads each request and replies with a real number, usually the same business day.

That says something about how ADD works. It doesn't try to sell a bigger pole than the site needs. It asks what the flag has to be seen from and names the height that clears it. If 100 ft does the job, that's the answer, and ADD's own words are that it would rather spend fifteen minutes on the phone than sell you the wrong pole. Its steel poles are made in the USA, which matters for public and federally funded projects, and it supplies them in all 48 contiguous states, with installation by its own crews in Maryland, Pennsylvania, Virginia and North Texas.