Flag lighting in Mexico: night and light pollution

A flag lit at night is a common sight at squares and public buildings in Mexico, and monumental flags can be seen from kilometres away. The law neither requires nor prohibits lighting, but the electrical installation and the light sent into the sky do have rules. This guide summarises them.

What the flag law says

The Law on the National Arms, Flag and Anthem sets no hours for raising and lowering the flag at civilian buildings. Under its article 16, at the buildings and places in article 15, seats of the authorities, schools, hospitals, customs, airports and public squares, the flag stays raised every day of the year, except in unforeseeable cases or force majeure. Article 17 entrusts designated staff with raising and lowering the flags on time on the relevant days, and with keeping them in a state appropriate to their use and dignity.

The law does not mention lighting. For a private person or a business, whether the flag is lit at night or lowered at dusk is a matter of custom and of the respect for the national symbol that article 32 requires in all cases.

Lighting a flagpole

A flag is usually lit with floodlights at the foot of the pole or on the ground nearby, aimed at the flag. On monumental flagpoles, Grupo Symac shows a lighting system among its installation work.

The electrical installation

Floodlights need a power supply to the pole. NOM-001-SEDE-2012, Electrical Installations (use), published in the Official Journal of the Federation on 29 November 2012 and in force since 29 May 2013, sets the safety specifications for electrical installations in Mexico. The Ministry of Economy lists it as current. An electrician can assess the specific installation, and the guide to flagpole safety covers earthing and lightning.

Light pollution

Light pollution is regulated mainly at local level. A well-known case is Ensenada, Baja California: its Regulation for the Prevention of Light Pollution, published in the state’s Official Gazette on 29 September 2006, protects the research of the National Astronomical Observatory of San Pedro Mártir, operated by the Institute of Astronomy of the UNAM. Its rules include:

• Light above the horizon: outdoor lighting avoids emitting light above the horizon and uses lamps that cause the least disturbance to astronomical observations (article 8).
• Scope: the regulation applies, among others, to ornamental lighting, illuminated signs, lighting of industrial and tourist areas and outdoor lighting of private homes (article 6).
• Signs: the lights of an outdoor sign are mounted at the top of the structure, and lighting signs from the base is prohibited (article 11).

A floodlight that lights a flag from below sends part of its light into the sky. In municipalities with rules like Ensenada’s, the direction and type of light used for an illuminated flag fall under those rules.

Flags with a logo

Lighting a corporate flag may be considered lighting of a sign, subject to the municipality’s sign regulations. The guide to flagpoles for businesses covers this case, and the guide to flagpole accessories describes the parts of the pole.