To establish guide criteria for the selection and usage
of 1-3⁄4" and 1-3⁄8" standard steel doors.
Standard steel doors are classified in four levels: Level 1 – 1-3⁄4" and 1-3⁄8" standard duty,
Level 2 – 1-3⁄4" heavy duty, Level 3 – 1-3⁄4" extra heavy
duty and Level 4 – 1-3⁄4" maximum duty.
Each of the four levels noted above offer a range
of construction models and designs to meet architectural requirements for preference and appearance.
The standard steel door construction models are full
flush, seamless and, stile and rail.
Recommended minimum gauge requirements for the
various levels and models of standard steel doors are
Selection of standard steel doors for general usage
is made by analyzing criteria such as frequency of
use, including subjection to and degree of possible
abuse. Other criteria to be considered in door selection are: conformance to local building codes and fire
code regulations; sound attenuation and/or insulation
requirements; and architectural design and appearance.
Table 2 is a reference aid matching standard duty,
heavy duty, extra heavy duty and maximum duty
doors with general usage requirements within the
classification of buildings. Where optional door levels and models are indicated, further analysis on an
individual job basis is recommended.
When unusual or special door usage conditions are
encountered, contact a representative member of the
Steel Door Institute for consultation and guidance.