Page 174 - Structural Steel Designers Handbook AISC, AASHTO, AISI, ASTM, and ASCE-07 Design Standards

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BUILDING CODES, LOADS, AND FIRE PROTECTION*

4.2 CHAPTER FOUR

or specifications either by direct reference or with modifications. The two current national model
building codes are the International Building Code (IBC) and the National Fire Protection Association
(NFPA) 5000.

4.2 APPROVAL OF SPECIAL CONSTRUCTION

Increasing use of specialized types of construction not covered by building codes has stimulated
preparation of special-use permits or approvals. Model codes individually and collectively have
established formal review procedures that enable manufacturers to attain approval of building
products. These code-approval procedures entail a rigorous engineering review of all aspects of
product design.

4.3 STANDARD SPECIFICATIONS

Standard specifications are consensus documents sponsored by professional or trade associations to
protect public safety and promote responsible use of a product or method. Examples of such speci-
fications are the AISC “Specification for Structural Steel Buildings,” the American Iron and Steel
Institute (AISI) “Specification for the Design of Cold-Formed Steel Structural Members,” the Steel
Joist Institute (SJI) “Standard Specifications Load Tables and Weight Tables for Steel Joists and Joist
Girders,” and the American Welding Society (AWS) “Structural Welding Code-Steel” (AWS D1.1).
Another important class of standard specifications defines acceptable standards of quality of
building materials, standard methods of testing, and required workmanship in fabrication and
erection. Many of these widely used specifications are developed by the ASTM. As need arises,
ASTM specifications are revised to incorporate the latest technological advances. The complete
ASTM designation for a specification includes the year in which the latest revision was approved.
For example, A992/A992M-05 refers to specification A992, last revised in 2005. The “M” indicates
that it includes alternative metric units.
In addition to standards for product design and building materials, there are standard specifica-
tions for minimum design loads, e.g., the ASCE “Minimum Design Loads for Buildings and Other
Structures” (SEI/ASCE 7-02), and the Metal Building Manufacturers Association “Low-Rise
Building Systems Manual.”
It is always advisable to use the latest editions of standards, recommended practices, and build-
ing codes. Also, it is wise to consult the cited source references for the complete criteria and full
context of the provisions.

4.4 BUILDING OCCUPANCY LOADS

Safe yet economical building designs necessitate application of reasonable and prudent design loads.
Computation of design loads can require a complex analysis involving such considerations as build-
ing end use, location, and geometry.
4.4.1 Building Code-Specified Loads
Before initiating a design, engineers must become familiar with the load requirements of the local
building code. All building codes specify minimum design loads. These include, when applicable,
dead, live, wind, earthquake, and impact loads, as well as earth pressures.
Dead, floor live, and roof live loads are considered vertical loads and generally are specified as
2
force per unit area, e.g., lb/ft or kPa. These loads are often referred to as gravity loads. In some
cases, concentrated dead or live loads also must be considered. Wind loads are assumed to act normal
2
to building surfaces and are expressed as pressures, e.g., lb/ft or kPa. Depending on the direction of

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