Standard Occupancy Structures - The Baseline for Most Construction Projects
Risk Category II is the most common building classification, representing approximately 80% of all construction in the United States. This category includes all buildings and other structures that do not qualify for Risk Categories I, III, or IV. It serves as the baseline standard for design wind loads with an importance factor of 1.00 (no modification to loads).
Risk Category II buildings represent typical occupancy and use where failure would not pose exceptional risk to human life or cause substantial economic disruption to the community.
Detached single-family residences, including custom homes, tract homes, and manufactured housing permanently installed on foundations.
Apartments, condominiums, townhouses, and multi-unit residential buildings with standard occupancy levels below assembly thresholds.
Assisted living facilities where residents are capable of self-preservation and the facility does not house bedridden or intensive care patients.
General office buildings, professional offices, banks, and business centers without essential facility functions.
Retail shops, shopping centers, department stores, and mall tenant spaces with occupancy below 300 persons.
Hotels, motels, inns, bed & breakfasts, and other transient lodging facilities providing temporary accommodations.
Restaurants, cafes, diners, fast food establishments, and food courts with occupant loads below assembly building thresholds.
Parking garages, parking decks, and covered parking facilities not considered essential to post-disaster operations.
Linear retail centers, strip centers, and neighborhood shopping centers with multiple tenant spaces.
Distribution centers, storage warehouses, fulfillment centers, and logistics facilities without hazardous materials exceeding threshold quantities.
Light industrial and manufacturing facilities producing non-hazardous materials and products with standard occupancy.
Auto repair shops, equipment service facilities, maintenance shops, and similar service-oriented industrial uses.
| Risk Category | Importance Factor | MRI (years) | Load vs Risk II | Primary Use |
|---|---|---|---|---|
| I | 0.87 | 300 | -13% | Agricultural, low hazard |
| II (Standard) | 1.00 | 700 | Baseline | Most buildings (80%) |
| III | 1.15 | 1,700 | +15% | Assembly, substantial hazard |
| IV | 1.15 | 3,000 | +15% | Essential facilities |
Risk Category II is the default classification for all buildings unless specific criteria justify another category. This simplifies the design process for most projects.
Be aware of the 300-person threshold for assembly buildings. Exceeding this requires Risk Category III classification regardless of building type.
For buildings with multiple uses, the highest applicable risk category governs the entire structure unless fire-rated separation allows independent design.
Risk Category II provides good flexibility for future tenant improvements and use changes without triggering structural upgrades for most scenarios.
Risk Category II represents the optimal balance between safety and economy for typical buildings:
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