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Tips to meeting Compliant Installation Requirements for Centralized STD-4C Mailboxes


Designing appropriate accessibility into every feature of a facility is a key consideration, and how the mailboxes are installed into that facility is no exception. The U.S. Postal Serve Operations Manual provides the U.S. Postal Service (USPS) with autonomy in determining the appropriate mode of delivery, including location and type of equipment. For new multi-family construction projects that mode is most often the STD-4C mailbox.

All wall-mounted STD-4C mailboxes to be serviced by the USPS must be installed according to specifications as outlined in the USPS STD-4C regulation. They must meet those design and installation regulations to receive the USPS Approved designation before the boxes can go into service and receive mail. Designs must also take into account other laws which govern accessibility.

Accessibility regulations can vary locally and regionally so consulting local building codes is recommended.

Here is an overview for accessible uses and USPS requirements to help you determine your project layout and design. For a complete course on these requirements and continuing education credit, visit

Meeting USPS Installation Requirements

Florence Corporation USPS Approved 4C mailbox products are designed to adhere to STD-4C regulations. To ensure your project complies with USPS regulations for wall-mounted mailboxes, your mailbox center must be installed according to the following USPS guidelines.

There must be at least one parcel locker for every 10 customer mailboxes in installations of 10 or more customer mailboxes. Parcel lockers must meet a minimum compartment height of 15 inches.

Mounting at specified heights Above Finished Floor (AFF) ensure USPS installation requirements are met.

Tips to meeting Compliant Installation Requirements for Centralized STD-4C Mailboxes

Installed height is measured to the bottom of the lowest door (compartment shelf), not the outside trim. Lock height is measured to the center of the lock for reach ranges.

Standards Governing the Design of Wall-Mounted Centralized Mail Receptacles. Federal Register/Vol. 69, No 171/September 3, 2004. Rules and Regulations POSTAL SERVICE, 39 CFR Part 111.

Meeting ADA Installation Requirements

For interior mailrooms, the ADA specifies that at least 5% of the total mailboxes must meet accessibility guidelines with installation heights 15 inches to 48 inches. Local regulations may override this percentage and require 100% compliance.

Accessibility regulations may vary by type of facility and by governing jurisdictions. Therefore, always consult local building officials and codes for applicable accessibility requirements that could affect your mailbox project. Sequential numbering of mailboxes (1-400), rather than assigning mailbox IDs that match apartment numbers, can allow flexibility in providing compartments meeting accessibility regulations. It also provides greater security for residents.

Mailboxes must comply with Section 309 specifications governing a location’s clear floor space, equipment height and operation.

Reach Ranges
An accessible mailbox must meet front and side reach guidelines from the installation wall. These ranges differ from USPS regulations.

2010 ADA Standards for Accessible Design, Department of Justice Code of Federal Regulations, ADA CHAPTER 2: SCOPING REQUIREMENTS, 228.2 Mail Boxes: Where mail boxes are provided in an interior location, at least 5 percent, but no fewer than one, of each type shall comply with 309. In residential facilities, where mail boxes are provided for each residential dwelling unit, mail boxes complying with 309 shall be provided for each residential dwelling unit required to provide mobility features complying with 809.2 through 809.4. The full text can be found at:

Meeting Fair Housing Act Installation Requirements

A requirement of the Fair Housing Act (FHA) and ANSI is accessible and usable public and common use areas including mailrooms and mailboxes.

ANSI does not provide a standard specific to mailboxes, so designers must consult the related human factors and performance specifications including space allowances and reach ranges, accessible routes and protruding objects. Installation heights are stipulated.

Reach Ranges
For mailboxes to be compliant with FHA, they must be within the reach ranges specified by ANSI.

Protruding Objects
Accessible routes for ANSI provides specifications for protruding objects located along walks, corridors and other passageways.

Joint Statement of The Department Of Housing And Urban Development And The Department Of Justice Accessibility (Design And Construction) Requirements For Covered Multifamily Dwellings Under The Fair Housing Act.

The Intersection of Compliance

In those cases where a development is subject to the accessibility requirements of more than one federal law, the requirements of each law must be met. To meet all installation specifications, plan for mailbox modules that fit between 28 inches and 40 inches from the finished floor. Modules with both mailboxes and parcel lockers can be installed between 15 inches and 48 inches from the finished floor.

Florence Provides Consultation

To assist you with selecting mailboxes that meet the specific requirements of your project, details about installed heights are noted on the Florence versatile™ 4C mailbox modules references on pages 18 through 29 in our 2018 Product Catalog and in our industry-unique online Revit Configurator. Guidance is also available through Florence Authorized Dealers and our Regional Sales Managers who are ready to consult on your project.

For a complete course and specifics on these requirements, visit

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