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BCA Helpline

Frequently Asked Questions (FAQs) - MODULE SPECIFIC QUESTIONS


LOSS OF FUNCTION

Q: How do I determine the “Number of customers served” for the Loss of Function for utilities?

A: The benefits calculation is based on the number of people served, not the number of their customers. Therefore, it is important to enter the number of people, which is usually based on population or the number of people per house.

Q: Where do I find the “Number of people served by police/fire stations” for Loss of Services?

A: This number is available from the stations or from city/community officials. Most cities with multiple stations are separated into districts that should have detailed population information.

Q: Where do I find the “Number of people served by hospitals” for Loss of Services?

A: Because hospitals are typically not operated by cities, the population served might be a complicated value to determine. Cities may have multiple hospitals, and some hospitals serve multiple communities. Some information, such as the number of beds and number of doctors per patient, may be found in annual reports for the hospital or on the hospital Web site. Contact the hospital to obtain their estimate on per capita served. Community planners and/or community officials may also be able to provide these estimates. If these methods are unproductive, provide a reasonable alternate methodology for determining population served with consideration for locations of other hospitals, geography, hospital size (number of beds, number of doctors), etc.

FLOOD

Q: What is a Depth-Damage Function (DDF)?

A: A DDF is an estimation of physical damage to a building based on a depth of flooding calculated as the percent damage to the structure and the contents. DDFs for displacement and loss of function at various flood depths are also estimated, but given in number of days. DDFs have been selected for various occupancy classes and are incorporated into the damage function library housed within the Version 4.5.5 Benefit-Cost Analysis (BCA) software.

Q: Where can I find the First Floor Elevation (FFE) of my structure?

A: The FFE can be obtained from the elevation certificate of the building. The National Flood Insurance Program requires communities to obtain lowest floor elevation information for newly constructed and substantially improved buildings in the Special Flood Hazard Area. For buildings in Zones A, elevations are measured at the top of the floor, and recorded on the elevation certificate in C2.a, b, d, and e. For buildings in Zones V, elevations are measured at the bottom of the lowest horizontal structural member, and are recorded on the elevation certificate in C2.c. Please reference the Dynamic Help topic “How do I determine the First Floor Elevation (FFE)” on the “Elevations” screen of the BCA software for more information.

Q: In the Flood module, how do I find the total size of a building?

A: The total size of the building can be found on tax records, appraisals, and surveys. The total size consists of the enclosed area within the building, including finished and unfinished basements, and the entire living space; however, it does NOT include porches, garages, car ports, patios, or other outside areas.

For flood mitigation of non-residential buildings use the default depth-damage functions (DDFs), enter only the area of the first floor for total size of the building. The default building and contents DDFs for non-residential buildings only apply to first floor damages.

For non-residential buildings using the library DDFs, enter the appropriate building area for the specific DDF chosen (usually this will be the first floor area) for the total size of the building.

Q: How do I analyze a house with a finished basement?

A: A house with a completely finished basement can be analyzed by making adjustments to the depth damage functions (DDF) for building, contents, and displacement. For houses with finished basements, select “2 or more stories” for the building type and “no” to indicate that the house does not have a basement. The first floor elevation (FFE) should be equal to the elevation of the top of the basement floor. Adjust the DDFs to zero for building, contents, and displacement below the elevation that flood water can enter the house. This adjustment can be made in two ways: a) use the Library DDF type option and select the default DDF, then enter zeros for flood depths below the entry point in the “Before Mitigation User Entered” DDF column, or b) use the Custom DDF type option and enter the default DDF values in the “Before Mitigation User Entered” DDF column starting at the flood depth that flood water enters the building. DDF values for non-integer flood depths must be interpolated and entered with the non-integer flood depth using the Custom DDF type option (flood depth values are not changeable when using the Library DDF type option). The FFE dynamic help from the Version 4.5.5 BCA software illustrates various scenarios. For buildings with finished basements, if the DDFs are not set to zero below the entry point for flood water, the module will greatly overestimate damages and the benefit-cost ratio (BCR) because it will calculate several feet of damages before water can enter the building.

A house with only a portion of the basement finished should be analyzed differently. The recommended approach is to conduct two BCA runs by dividing the house into two structures.

For example: A 1,000-square-foot (sf) house is one story with a full (1,000 sf) basement, where 60 percent (600 sf) of the basement is fully finished and 40 percent (400 sf) is unfinished.

Add two structures into the flood module and make the following adjustments. Begin with the BCA module run for the first structure, which is the part of the house with the finished basement and the first floor area directly above it. Select a 2 or more stories residential building type, and no basement. The building area is the 60 percent of the first floor area plus the finished basement area: (600 sf) + (600 sf) = 1,200 sf. Set the FFE equal to the top of the finished basement floor. Adjust the DDFs to account for the elevation that flood water can enter the house.

The second BCA module run will be for the second structure representing the unfinished basement and the first floor area directly above it. Select a one story house with basement. The building area is 40 percent of the first floor area plus the unfinished basement area: (400 sf) + (400 sf) = 800 sf. Set the FFE equal to the top of the first habitable floor (in this case the above grade floor). The DDFs do not need to be adjusted.

Do not enter the full project cost in each structure because that will be double counting the project cost. BCA Helpline recommends entering the total project cost in one of the structures and zero project cost in the other.

EARTHQUAKE

Q: The Loss of Service “benefit for critical facilities” is not incorporated into my final report for the Earthquake-Structural module. Am I getting credit for it?

A: No, currently the Earthquake-Structural module only incorporates the annual budget values entered for “Other” loss of service types. This is a known bug in the Version 4.5.5 Earthquake-Structural module. This bug will be corrected in the next release of the software. To ensure the final BCR adequately incorporates the Loss of Service for critical facilities, calculate the Loss of Service total under the appropriate critical facility by answering the loss of service questions and pressing the “Show Total” button. Manually transfer this value, multiplied by 365, into the Annual Budget under the “Other” radio button. Select “Other” using the drop down menu under the Service Name and provide adequate justification and documentation in the Justification/Documentation field at the bottom of the page. Such justification might read: “Using Other Services annual budget as workaround for known bug with critical service calculations. See fire station, police station, and hospital loss of service calculations for the daily value of service.”

Q: How is displacement time and functional downtime computed in the Version 4.5.5 Earthquake-Structural module?

A: Please refer to the “Analysis” tab of the “Seismic Data” screen in the Earthquake-Structural module (as shown in the screenshot below):

“Analysis” tab of the “Seismic Data” screen in the Earthquake-Structural module

Average annual loss – Relocation (displacement) is computed using the monthly and one-time costs entered on the “Economic Values” tab in conjunction with the recovery time from HAZUS Table 15.10 (see below) without the multiplier from HAZUS Table 15.11 (see below). Recovery time for each occupancy class (building use) includes clean-up time, repair time, and other items related to implementing repairs such as decision making, contract negotiation, preparation of contract documents, inspections, mobilization, and occupancy following construction completion.

Average annual loss – Loss of Rental Income is computed using the monthly rental loss entered on the “Economic Values” tab in conjunction with the recovery time from HAZUS Table 15.10 (see below) without the multiplier from HAZUS Table 15.11(see below). Rental properties will incur a loss of rental income while the damaged building is being repaired for the full recovery time.

Average annual loss – Loss of Business Income (includes loss of public service using the annual operating budget [AOB] for public facilities) is computed using the monthly income loss or AOB, as appropriate, in conjunction with the recovery time from HAZUS Table 15.10 (see below) multiplied by the interruption time multipliers from HAZUS Table 15.11 (see below). The ability of a business or public service to begin to operate in a time period less than the recovery time from Table 15.10 is reflected for occupancy classes (building use) with multipliers (from Table 15.11) less than one.

Table 15.10: Building Recovery Time

Reprinted from the HAZUS-MH MR3 Technical Manual, FEMA 2003

Table 15.11: Building and Service Interruption Time Multipliers

Reprinted from the HAZUS-MH MR3 Technical Manual, FEMA 2003

The Version 4.5 Earthquake-Structural module displays functional downtime (see the table below) for loss of business income or loss of public service. This table reflects the values from HAZUS Table 15.10 multiplied by the values from HAZUS Table 15.11. The values below are not used for displacement unless the multipliers in Table 15.11 are equal to one. The table below can be accessed on the “Vulnerability” tab of the “Seismic Data” screen by clicking on the “Show All Input Parameters” button. The displacement days from HAZUS Table 15.10 are not displayed in the module but are used in the analysis, as previously explained.

Casualties and Loss of Function

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Last Modified: Friday, 17-Sep-2010 07:48:37 EDT