Flagpole heights: how they relate to the flag

What is the right height for a flagpole? Law 5,700 does not answer directly, but it offers something rare: an official relation between the flag and the pole. Brazilian manufacturers publish similar guides, and local rules, from the municipality to the condominium, limit what is possible on each plot. This guide brings these factors together.

The 1/7 to 1/5 rule

Under article 21 of Law 5,700, at public offices and military units, when the flag is raised on a pole in the ground, its width is no more than 1/5 and no less than 1/7 of the height of the pole. Read the other way round, the rule gives the range of heights for each flag:

The rule formally applies to public bodies, but it is the official reference available for other poles. The flag size calculator does the calculation for each height.

The manufacturers’ guide

B&B Iluminação’s datasheet has a flag-to-pole guide for the range the manufacturer produces in series, from 6 to 12 metres:

The manufacturer’s ideal heights fall within the range of article 21, close to a width of one sixth of the height. Outside the 6 to 12-metre range, B&B refers to a special project on request.

Heights available

The sheets consulted give the following heights:

• B&B Iluminação: telescopic galvanised steel poles of 6 to 12 metres clear height, embedded or flanged;
• Metalsinter, according to the sheet on AECweb: tubular poles of 4 to 15 metres and polygonal poles of 18 to 30 metres.

The clear height is the part above ground. On B&B’s embedded pole, there is also 1 metre embedded in the foundation. The guide to types of flagpoles describes these forms.

Wind and height

The taller the pole and the larger the flag, the greater the wind load on the base and the foundation. Manufacturers design poles to the ABNT NBR 6123 standard on wind forces; Metalsinter gives poles designed for winds of up to 160 km/h. A lower pole or a smaller flag reduces the load. The guide to flagpole safety covers wind warnings and lightning.

What limits the height on a plot

Besides the structural design, other factors limit the height on a plot:

• the municipality: under article 30 of the Constitution, controlling the use and occupation of urban land falls to the municipalities, and the building code may treat the pole as a work;
• the condominium: the Civil Code and the condominium’s rules may limit what is installed in common areas and on the façade;
• the power grid: the distribution company Neoenergia Elektro states that walls, balconies and roofs may not be built less than 2.5 metres from the power grid and that antennas, whose supports are usually metal, are kept away from the grid;
• advertising: in São Paulo, the Clean City Law allows indicative advertisements on totems or tubular structures up to 5 metres high, structure included, which may apply to a pole with a company flag.

The guide to installing a flagpole goes into these points.