Annex E. Types of Construction
This annex is not part of the requirements of the NFPA document but is listed for informational purposes.
Table E.1. Fire Resistance Ratings (in hours) for Type I through Type V Construction
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[1] See A-3 1 in NFPA 220.
[2] "H" indicates heavy timber members; see text for requirements.
[3] Exterior nonbearing walls meeting the conditions of acceptance of NFPA 285, Standard Method of Test for the Evaluation of Flammability Characteristics of Exterior Non-Load-Bearing Wall Assemblies Containing Combustible Components Using the Intermediate-Scale, Multistory Test Apparatus, shall be permitted to be used.
The five different types of construction can be summarized briefly as follows (see also Table E.2):
|
Construction |
Maximum Number of Stories Permitted |
|---|---|
|
Type |
|
|
V Non-Rated |
2 |
|
V Non-Rated, Sprinklered |
3 |
|
V One-Hour Rated |
3 |
|
V One-Hour Rated, Sprinklered |
4 |
|
IV Heavy Timber |
4 |
|
IV Heavy Timber, Sprinklered |
5 |
|
III Non-Rated |
2 |
|
III Non-Rated, Sprinklered |
3 |
|
III One-Hour Rated |
4 |
|
III One-Hour Rated, Sprinklered |
5 |
Type I is a Fire-Resistive construction type. All structural elements and most interior elements are required to be noncombustible. Interior, nonbearing partitions are permitted to be 1 or 2 hour rated. For nearly all occupancy types, Type I construction can be of unlimited height.
Type II construction has 3 categories, Fire-Resistive, One-Hour Rated and Non-Rated. The number of stories permitted for multifamily dwellings varies from 2 for Non-Rated and 4 for One-Hour Rated to 12 for Fire-Resistive construction.
Type III construction has two categories, One-Hour Rated and Non-Rated. Both categories require the structural framework and exterior walls to be of noncombustible material. One-Hour Rated construction requires all interior partitions to be one-hour rated. Non-Rated construction allows nonbearing interior partitions to be of non-rated construction. The maximum permitted number of stories for multifamily dwellings and other structures is 2 for Non-Rated and 4 for One-Hour Rated.
Type IV is a single construction category which provides for heavy timber construction. Both the structural framework and the exterior walls are required to be noncombustible except that wood members of certain minimum sizes are allowed. This construction type is seldom used for multifamily dwellings but, if used, would be permitted to be 4 stories high.
Type V construction has two categories. One-Hour Rated and Non-Rated. One-Hour Rated construction requires a minimum of one-hour rated construction throughout the building. Non-rated construction allows non-rated interior partitions with certain restrictions. The maximum permitted number of stories for multifamily dwellings and other structures is 2 for Non-Rated and 3 for One-Hour Rated.