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USPS Commercial Mailbox STD-4C Regulations & Requirements

Standard 4C Mailbox Specifications

USPS Approved STD-4C Mailbox RegulationsAll new designs approved for new construction and major renovation require U.S. Postal Service STD-4C compliant mailbox systems. USPS commercial mailbox specifications include:

  • Minimum size requirement of 12” w x 15” d x 3” h
  • Minimum number of parcel lockers based on a 1:10 parcel locker to customer compartment ratio
  • Improved security requirements for entire receptacle
  • Standardizes and improves tenant compartment lock design
  • Adds testing requirements to verify indoor/outdoor use
  • Meets Americans with Disabilities Act (ADA) standards

US Mail Supply carries Florence Versatile 4C mailbox suites which are designed to meet or exceed the USPS specifications outlined above and in the *Federal Register/Vol. 69, No. 171/September 3, 2004/Rules and Regulations POSTAL SERVICE, 39 CFR Part 111, Standards Governing the Design of Wall-Mounted Centralized Mail Receptacles.

4C Horizontal Mailbox GuidelinesADA Compliance – the USPS 4C Standard includes a requirement to meet Americans with Disabilities Act** (ADA) standards. (See pg. 53,809*) The ADA section that covers clear space and reach dimensions is noted below and can be found here.

ADA Standards for Accessible Design, ACCESSIBILITY GUIDELINES FOR BUILDINGS AND FACILITIES Appendix A to Part 36 – Standard for Accessible Design Section 4.2 Space Allowance and Reach Ranges

IMPORTANT NOTE TO ALL ARCHITECTS, SPECIFIERS, DESIGN LAYOUT PROFESSIONALS AND INSTALLERS – All 4C Units shall be designed such that they are in compliance with the following installation requirements:

  1. At least one customer compartment shall be positioned less than 48 inches from the finished floor
  2. No parcel locker compartment (interior bottom shelf) shall be positioned less than 15 inches from the finished floor
  3. No tenant lock shall be located more than 67 inches above the finished floor
  4. No customer compartment (interior bottom shelf) shall be positioned less than 28 inches above the finished floor
  5. The USPS Arrow lock shall be located between 36 and 48 inches above the finished floor
Shop USPS approved mailboxes available for sale from U.S. Mail Supply.
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