264 Chapter 11
sures, smoke barriers, floors, ceilings, and roofs. Fire ratings are based on the number of hours a build-
ing element will resist fire before it is adversely affected by the flame, heat, or hot gases.
All buildings are classified into one of five or six types of construction. Type I buildings are the most
fire-resistive and typically contain structural members that are noncombustible. Type I buildings also
have the highest fire rating, usually 2 to 4 hours. Type V buildings (Type VI in the SBCCI codes) have
the lowest fire rating and are typically of wood-frame construction.
Adjuncts to Building Codes.
Building codes typically have additional companion codes and standards that govern other aspects of
construction, which, with the exception of the electrical code, are usually published by the same group
that publishes the model building codes.
Model codes frequently use industry standards developed by trade associations, government agen-
cies, and standards-writing agencies such as the American Society for Testing and Materials (ASTM),
the American National Standards Institute (ANSI), and the National Fire Protection Association (NFPA).
Building codes reference these standards by name, number, and date of latest revision and become law
when a code is accepted by a jurisdiction. In addition, there may be local jurisdictions that maintain en-
ergy-conservation codes, health and hospital codes, fabric flammability regulations, and codes that reg-
ulate construction and finishes.
Test Ratings and Fire-Resistant Materials and Finishes.
It is estimated that roughly 75 percent of all codes deal with fire and life-safety issues, and the primary
aim of fire codes is to confine a fire to its area of origin, thus limiting its spread and preventing flashover.
To facilitate this, all approved materials and construction assemblies referred to in building codes are
assigned ratings based on standardized testing procedures. The rating of an assembly is ascertained
by evaluating its performance during testing and by examining its fire-resistive properties. There are
hundreds of standardized tests for building materials and construction assemblies.
Any approved testing laboratory can undertake the testing of building materials, provided that stan-
dardized procedures are followed. The American Society for Testing and Materials (ASTM), the National
Fire Protection Association (NFPA), and Underwriters Laboratories (UL), in collaboration with the Amer-
ican National Standards Institute (ANSI), are among the best-known organizations that have developed
a large variety of standardized tests and testing procedures.
Upon being subjected to one of the standard tests, a material is given a rating based on its perform-
ance during the test. For construction assemblies tested according to ASTM E-119, the rating given is ac-
cording to time—that is, how long an assembly will contain a fire, retain its structural integrity, or both. The
test evaluates a construction assembly’s performance in the face of the temperature rise on the protected
side of the assembly, the amount of smoke, gas, or flame that penetrates the assembly, and the assem-
bly’s structural performance during exposure to fire. The ratings are 1-hour, 2-hour, 3-hour, and 4-hour;
20-, 30-, and 45- minute ratings are also used for doors and other opening assemblies. Assemblies that
consultants and field observers must be concerned with include fire walls, fire-separation walls, shaft en-
closures (such as stairways, exits, and elevators), floor/ceiling constructions, and doors and rated glazing.
Building codes typically have tables that stipulate the type of construction that meets the different
hourly ratings. Thus, when a building code states that a 1-hour-rated partition assembly is required be-
tween an exit corridor and an adjoining tenant space, the designer must select and detail a design that
incorporate the requirement for 1-hour construction.