Most municipalities adopt a version of the International Fire Code with specific modifications depending of the specific needs of the area.

For adopting code compliant address number display, the IFC reads:

SECTION 505 [IFC]

PREMISES IDENTIFICATION

505.1 Address numbers. New and existing buildings shall have approved address numbers, building numbers or approved building identification placed in a position that is plainly legible and visible from the street or road fronting the property.The IFC does not specify absolute defined standards. There are several situations which would not comply with the code, and make it difficult for emergency responders to find your address.

	Address numbers which are too small to be visible from the street.
	Address numbers which are distorted by being too "squat" in appearance
	Address numbers which are distorted by being too "stretched" in appearance.
	Address numbers which are distorted by using an over-stylized design.
	Address numbers which are obscured by foliage for architectural elements.
	Address numbers which are difficult to read because of color contrast, light letters on light background.
	Address numbers which are difficult to read because of color contrast, dark letters on dardk backgound.
	Address numbers which are spelled out alphabetically. These addresses are not only against code but create confusion for emergency responders customers as well. Human eyes are accustomed to looking for numerical address notation and may miss the spelled out address.
	Address numbers which are vertically alined. Although vertical numbers are not specificaly addressed in the IFC, it may cause confusion, as most drivers would be looking for horizontal numbers

Many cities specify more defined standards, for example, the City of Tucson has adopted Pima County standards:

CITY OF TUCSON 2006 FIRE CODE MODIFICATIONS [TFC]
13
SECTION 505 - PREMISES IDENTIFICATION

Section 505.1 Address numbers. Is hereby AMENDED by DELETING everything after the first sentence, and ADDING the following:
Address numbers shall be in accordance with Pima County address display requirements.

Pima County Address Display Requirements:

Residential
< 50 feet from curb requires 3" numbers displayed on the building.
> 50 feet from the curb requires 3" numbers displayed a minimum of 36" above ground at the primary access point.

Apartments
Entrance numbers shall be 12"
Building numbers shall be 15"
Apartment numbers ranges displayed below building numbers shall be 8"
Apartment numbers ranges displayed on signage near the building shall be 2"
Apartment numbers shall be 3" on outside entrances and 1" for interior (hallway) entrances.
Number ranges are required on buildings or signage.

Commercial
Building < 50 feet from the curb require 12" numbers displayed on the building.
Buildings > 50 feet from the curb require 15" numbers displayed on the building.
Tenant space numbers shall be 3"
Address range may be displayed in 12" numbers on the building.

RV and Mobile Home Parks
Entrance numbers shall be 12"
Building numbers shall be 6"
Space numbers shall be 3"

Miscellaneous Information
All addresses must be posted prior to inspection.
All sizes are the minimum required .
For additional information on the placement of addresses call the Addressing Department @ 740-6480
The complete address shall be displayed on all comer buildings.
Addresses shall be displayed and visible from both directions of approaching vehicles.
Numbers and letters shall be made of durable and clearly visible material. (Paint is not an acceptable material).
Numbers and letters shall be of colors contrasting with the background to which they are attached.
Numbers and letters shall have a minimum proportion ratio of 6:1 (height to width).
Numbers shall not be spelled.

We hope you find this information helpful. Please remember us for your address number and safety sign needs.