The Significant Changes to the 2006 International Codes series has been developed by the International Code Council and published by Thomson-Delmar Learning to accommodate the transition from the 2003 to the 2006 editions of the International Codes. To purchase books in the series, visit the Code Council website.

International Fire Code

SUBJECT: Definition for High-Hazard Group H-3
CHANGE TYPE: Clarification

202 General Definitions
High-Hazard Group H-3. Buildings and structures that contain materials that readily support combustion or present a physical hazard shall be classified as Group H-3. Such materials shall include, but not be limited to, the following:

Class I, II or IIIA flammable or combustible liquids which are used or stored in normally closed containers or systems pressurized at less than 15 pounds per square inch (103 kPa) gauge or less

Combustible fibers

Consumer fireworks, 1.4G (Class C Common)

Cryogenic fluids, oxidizing

Flammable solids

Organic peroxides, Classes II and III

Oxidizers, Class 3, that are used or stored in normally closed containers or systems pressurized at 15 pounds per square inch gauge (103 kPa) or less

Oxidizers, Class 2

Oxidizing gases

Unstable (reactive) materials, Class 2

Water-reactive materials, Class 2

CHANGE SIGNIFICANCE: In the 2003 edition, the International Fire Code (IFC) was changed to place oxidizers and flammable liquids at an equivalent level with respect to occupancy classifications. All open-use conditions and those storage and closed-use conditions involving vessels or systems pressurized in excess of 15 psig were linked to the H-2 occupancy classification. Storage and closed-use conditions in vessels or systems having a pressure less than 15 psig were linked to the H-3 occupancy classification. However, neither the H-2 nor the H-3 provisions addressed the case of vessels or systems with exactly 15 psig, presenting an anomaly in the code. This was addressed by modifying the H-3 definition to include the 15 psig case.

It should be noted that the provisions for storage and closed use of Class 3 oxidizers at pressures not exceeding 15 psig were approved for publication in the 2003 IFC but were inadvertently omitted from early printings. They were later added by errata and now appear in the 2006 edition. The text associated with this revision is shown here in blue.

The original basis for the 15 psig threshold is American National Standards Institute (ANSI) Standard B31.3, Section 300.1.3, which excludes piping that operates below that pressure and carrying certain nonhazardous materials from having to comply with ANSI B31.3. Because ANSI B31.3 uses 15 psig as a suitable breakpoint for application of that standard, that pressure was selected as a basis for applicability of selected IFC hazardous materials regulations, including the breakpoint for H-2 versus H-3 occupancy classification for uses containing sufficient quantities of flammable and combustible liquids or oxidizers.