Location Surrounding Detail Fields

AIR's individual risk methodology follows a structured, logical approach that groups building characteristics according to their function to reflect the contribution of each characteristic to overall building performance. For information about the individual risk characteristics that are supported in a specific model, refer to the "Model in Touchstone” chapter in the model description, which is available on AIR's Client Portal.

The following table describes the Touchstone location fields related to the surrounding detail for this location. Click the following links for information about Location Building Detail fields, such as custom elevation and flood fields, and about Location Connection Detail fields, such as Foundation Type.

Field

Perils

Description

Validation Rules

Default Value

Pounding

       CA EQ

       HI EQ

       JP EQ

       US EQ

One of the following values to describe the distance from the building at this location to the closest structure, which, if not adequate, can cause the two structures to collide during earthquake shaking:

       Unknown/default (0)

       0-0.25 m (1)

       0.25-0.5 m (2)

       0.5-1.0 m (3)

       1.0-2.0 m (4)

       >2.0 m (5)

 

Note that this field was previously named "IrProximity" in UNICEDE®/px Primary Data Exchange Format (UPX) and UNICEDE®/fx Facultative Data Exchange Format (UFX) data.

 

This factor usually concerns high-rise buildings in densely built areas, like business districts of cities. If the gap between adjacent tall buildings is not adequate, there is potential danger of the two structures colliding during earthquake shaking. This phenomenon is known as the "pounding effect."

 

Severe damage may occur when the floors of the building are at different elevations, and the impact of one building's floors can destroy the columns in the adjacent building.

       Optional

       Defaults to a value in the Touchstone user interface

Unknown/default (0)

Tree Exposure

       HI TC

       US HU

       US ST - Straight-Line Winds, Tornados

One of the following values to indicate whether tree hazard exists around the building at this location:

       Unknown/default (0)

       No (1)

       Yes (2)

 

Trees snap in strong winds and can damage adjacent buildings.

       Optional

       Defaults to a value in the Touchstone user interface

Unknown/default (0)

Small Debris

       HI TC

       US HU

       US ST - Straight-Line Winds, Tornados

One of the following values to indicate whether there is potential for small debris within a radius of 200 feet from the building at this location:

       Unknown/default (0)

       No (1)

       Yes (2)

 

Small debris, such as roof gravel, trash bins, or tree branches, may be picked up by high wind and breach window glass. Small debris can be carried to all elevations at high wind speed.

       Optional

       Defaults to a value in the Touchstone user interface

Unknown/default (0)

Large Missile

       HI TC

       US HU

       US ST - Straight-Line Winds, Tornados

One of the following values to indicate whether there is potential for large missiles within a radius of 100 feet from the building at this location:

       Unknown/default (0)

       No (1)

       Yes (2)

 

Garden furniture or wood planks or studs dislodged from nearby buildings may become missiles at high wind speed and breach the building envelope.

       Optional

       Defaults to a value in the Touchstone user interface

Unknown/default (0)

Terrain Roughness

       HI TC

       US HU

       US ST - Straight-Line Winds, Tornados

One of the following values to describe the terrain conditions around the building at this location:

Terrain Roughness Value

Description

Unknown/default (0)

 

Large city centers (1)

Large city centers with at least 50% of the buildings having a height in excess of 70 feet (21.3 m)

You should limit the use of this exposure category to areas for which terrain representative of this category prevails in the upward direction for a distance of at least 0.5 mi. (0.8 km) or 10 times the height of the building or other structure, whichever is greater. Possible channeling effect on building will be taken into account.

Urban and suburban areas, wooded areas (2)

Urban and suburban areas, wooded areas, or other terrain with numerous closely spaced obstructions having the size of single-family dwellings or larger

 

You should limit the use of this exposure category to areas for which terrain representative of this category prevails in the upwind direction for a distance of at least 1,500 feet (460 m) or 10 times the height of the building or other structure, whichever is greater.

Open terrain with scattered obstruct (3)

Open terrain with scattered obstructions having heights generally less than 30 feet (9.1 m)

 

This category includes flat, open country and grasslands.

Flat, unobstructed areas (4)

Flat, unobstructed areas exposed to winds flowing over open water for a distance of at least 1 mile (1.61 km)

 

This exposure category applies only to buildings and other structures exposed to the winds coming off the water. This exposure category extends inland from the shoreline a distance of 1,500 feet (460 m) or 10 times the height of the building or structure, whichever is greater.

       Optional

       Defaults to a value in the Touchstone user interface

       You should use this field in conjunction with the adjacent building height.

Unknown/default (0)

Adjacent Building Height

       HI TC

       US HU

       US ST - Straight-Line Winds, Tornados

Average height of buildings adjacent to the building at this location

 

Express the average height as an average number of stories.

 

A value of 0 for this field represents Unknown/default.

       Optional

       You should use this field in conjunction with the terrain roughness.

 

Custom Flood Standard of Protection

       CE IF

       US HU

       US IF

       JP IF

       JP TY

Increase in flood protection for the building at this location that custom flood protection systems, such as levees or flood walls, provide for single risks (for example, for large industrial facilities)

 

This field represents the height of a custom flood protection system (in feet) above the ground surface at the building at this location. A value of -999 for this field in your import data indicates that custom protection is not present. This value is also the default setting for this field. Touchstone does not allow any other negative values.

 

Note that setting this field to 0 indicates that the basement at this location has been equipped with flood protection to a level that is equivalent to the elevation of the adjacent ground surface.

       Optional

       Can be a numeric value between 0 and 30000 (10000 when entering values using the Touchstone user interface), inclusive, or -999

 

Custom Flood Zone

       CE IF

One of the following values to indicate whether the building at this location is part of a custom flood zone:

       Default (0)

       Zone 1 (1)

       Zone 2 (2)

       Zone 3 (3)

       Zone 4 (4)

 

If you specify Default (0) as the value for this field, Touchstone assumes that no zone has been defined and includes all locations for analysis.

 

Defining this modifier for a location helps to filter the locations defined with custom zones to include in the analysis. This ability is especially useful if only certain zones can be included for protection. You can specify flood zones in Touchstone by clicking the pencil icon next to the Inland Flood peril selection in the Analysis Settings pane.

Optional

 

Custom Elevation

       US HU

       US IF

       JP IF

       JP TY

Elevation of the local ground surface (in feet) at the building at this location

 

This field represents the elevation of the grade (local ground surface) with respect to the datum (NAVD88) nature of finish in basements of buildings.

 

A value of -999 for this field represents Unknown/default.

 

The custom elevation (i.e., a value other than -999) overrides the underlying modeled digital terrain (DTM) elevation.

Optional

 

Base Flood Elevation

       US HU

       US IF

Water elevation (in feet) for a 100-year flood at the building at this location, as defined by FEMA

 

Touchstone supports this field for all residential, commercial, and small industrial buildings.

 

A value of -999 for this field represents Unknown/default.

 

FEMA defines the Base Flood Elevation (BFE) as the "water surface elevation corresponding to a flood having a 1% probability of being equaled or exceeded in a given year."

 

Touchstone assumes that the building at this location has its lowest floor (including the basement, if any) at the BFE.

       Optional

       The BFE cannot be less than the local grade elevation, since both are measured with respect to NAVD88. If you set the BFE to a value that is less than the local grade elevation, Touchstone assumes that the BFE is unknown.

       The value that you set for the first floor height overrides the BFE.

       If you specify any of the following construction or occupancy class codes for this location, Touchstone ignores your setting for this field:

       IFM (400 series occupancy class codes)

       200 series construction class codes (including automobiles and pleasure boats)

 

 


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Touchstone 5.0 Updated August 28, 2018