WORKSHEET FOR ASSIGNING SPECIFIC STRUCTURES
TO PERFORMANCE GROUPS
This appendix allows adjustment of the performance group based on occupants or the unique features of a building.
The table in Appendix B can be used for two purposes. If a facility is being evaluated, and there is no clear means of determining a performance group because the facility is not similar to occupancies described in Table 303.1, Appendix B can be used as a subjective means of evaluating the associated risks. From that evaluation, a performance group can be developed.
A second use of Appendix B would be to evaluate the impact of unusual features in a building or facility for which the performance group is identified in Table 303.1. For instance, if for some reason a facility that would normally be categorized as a Performance Group II is of extremely high importance to a community and contains some unusual hazards, Appendix B might be used as a means of evaluating whether the facility should be treated as a Performance Group III or IV.
The completed table in this user’s guide shows levels of risk assigned to several typical occupancies and the resultant performance group. In each case, it is a subjective analysis, and there are items in the completed table with which the user may disagree. The intent, however, is to provide a means of channeling the thought process in determining the performance group of a building or facility by reviewing the various risk factors that may be contained within the building. As more risk factors are identified, the performance group would be increased.
The committee intended that this table be used as a subjective analysis rather than as a numerical analysis. The user could decide to assign numerical values in this table as well. That approach, however, may result in all risk factors being inappropriately treated equally; the subjective analysis would allow the user to weight the risk factors in the analysis. Another problem with a numerical analysis is that multiple facility types would need to be evaluated in order to establish a database of relative rankings. Otherwise, the numbers would be meaningless.
WORKSHEET FOR ASSIGNING SPECIFIC STRUCTURES TO PERFORMANCE GROUPS RISK FACTORS Small Agricultural
Storage Building (U)
15-Unit Apartment Building (R-1) Outdoor Sports Stadium (A-5) Large Hospital (I-2) Primary Employer Factory (F-1) Blank Space for Specific Structure Occupant Load. Maximum number of persons permitted to be in the structure or a portion of the structure. Duration. Maximum length of time that the structure is significantly occupied. Sleeping. Do people normally sleep in the building? Occupant Familiarity. Are occupants expected to be familiar with the building layout and means of egress? Occupant Vulnerability. What percentage of occupants, employees or visitors is considered to comprise members of a vulnerable population. Dependent Relationships. Is there a significant percentage of occupants or visitors who are expected to have relationships that may delay egress from the building? HAZARD FACTORS Nature of the Hazard. What is the nature of the hazard, and what are its impacts on the occupants, the structure and the contents? Internal or External Hazard. Is the hazard likely to originate internally or externally or both? LEVEL OF IMPORTANCE Population. Are large numbers of people expected to be present? Essential Facilities. Is the structure required for emergency response or post-disaster emergency treatment, utilities, communications or housing? Damage Potential. Is there significant risk of widespread and/or long-term injuries, deaths or damage possible from the failure of the structure? Community Importance. Is the structure or its use largely responsible for economic stability or other important functions of the community? SPECIFIC ADJUSTMENTS Are the design performance levels adequate and appropriate for the specific structure? OVERALL RISK, HAZARD, IMPORTANCE
FACTORS AND PERFORMANCE GROUP
I II III IV III1 1. Table 303.1 normally classifies this occupancy as Performance Group II.