APPENDIX A - Seismic Terms, Tables and Figures: Seismic Design Force, (F p ) G-force that the unit must be able to withstand. This number is calculated using the factors described below. a S 0.4 P DS z FP ( g) 1 2 RP h I P Where: Amplification Factor (a p ) equals 2.50 for evaporative cooling equipment. Found on ASCE 7-05 Table 13.6-1. Response Mod Factor (R p ) equals 2.0 for spring isolated equipment or 2.5 for rigidly mounted equipment. Found on ASCE 7-05 Table 13.6-1. Importance Factor (I p ) equals 1.0 for non-critical or 1.5 critical applications. Found on IBC 2006 Table 1604.5. Installation (z/h) equals 0 if the unit is at grade or 1 if the unit is on a rooftop. Amplification Factor (a p ) 2.5 for flexible components or flexibly attached components. Due to its low inherent natural frequencies (above 16.7Hz is considered rigid), most evaporative cooling equipment falls under the definition of flexible. Therefore the default for Cooling Towers is 2.5. See Table 13.6-1 in the American Society of Civil Engineers (ASCE) Standard 7-05, to which IBC often references, for more information. Excerpt From ASCE 7-05 Table 13.6-1 SEISMIC COEFFIECIENTS FOR MECHANICAL AND ELECTRICAL COMPONENTS MECHANICAL AND ELECTRICAL COMPONENTS Wet-side HVAC, boilers, furnaces, atmospheric tanks and bins, chillers, water heaters, heat exchangers, evaporators, air separators, manufacturing or process equipment, and other mechanical components constructed of high-deformability materials. VIBRATION ISOLATED COMPONENTS AND SYSTEMS Spring isolated components and systems and vibration isolated floors closely restrained using built-in or separate elastomeric snubbing devices or resilient perimeter stops. a p a 2.5 (for flexible components) R p b 2.5 2.5 2.0 a A lower value for a p is permitted where justified by detailed dynamic analyses. The value for a p shall not be less than 1.0. The value of a p equal to 1.0 is for rigid components and rigidly attached components. The value of a p equal to 2.5 is for flexible components and flexibly attached components. b Components mounted on vibration isolators shall have a bumper restraint or snubber in each horizontal direction. The design force shall be taken as 2 F p if the nominal clearance (air gap) between the equipment support frame and restraint is greater than 0.25 in. If the nominal clearance specified on the construction documents is not greater than 0.25 in., the design force is permitted to be taken as F p. Response Modification Factor (R p ) 2.5 for non-isolated evaporative cooling equipment. 2.0 for vibration isolated evaporative cooling equipment. Table 13-6.1 of ASCE 7-05 (above) provides additional information.
Occupancy Category I, II, III or IV depending on the nature of the building occupancy. Table 1604.5 in the IBC 2009 Code Book defines each of the four categories in detail. Occupancy Category I II IBC 2006 Table 1604.5 OCCUPANCY CATEGORY OF BUILDINGS AND OTHER STRUCTURES Nature of Occupancy Buildings and other structures that represent a low hazard to human life in the event of failure, including but not limited to: Agricultural facilities. Certain temporary facilities. Minor storage facilities. Buildings and other structures except those listed in Occupancy Categories I, III, and IV. III IV Buildings and other structures that represent a substantial hazard to human life in the event of failure, including but not limited to: Covered structures whose primary occupancy is public assembly with an occupant load greater than 300. Buildings and other structures with elementary school, secondary school or day care facilities with an occupant load greater than 250. Buildings and other structures with an occupant load greater than 500 for colleges or adult education facilities. Healthcare facilities with an occupant load of 50 or more resident patients, but not having surgery or emergency treatment facilities. Jails and detention facilities. Any other occupancy with an occupant load greater than 5,000. Power-generating stations, water treatment for potable water, waste water treatment facilities and other public utility facilities not included in Occupancy Category IV. Buildings and other structures not included in Occupancy Category IV containing sufficient quantities of toxic or explosive substances to be dangerous to the public if released. Buildings and other structures designed as essential facilities, including but not limited to: Hospitals and other health care facilities having surgery or emergency treatment facilities. Fire, rescue and police stations and emergency vehicle garages. Designated earthquake, hurricane or other emergency shelters. Designated emergency preparedness, communication, and operation centers and other facilities required for emergency response. Power-generating stations and other public utility facilities required as emergency backup facilities for Occupancy Category IV structures. Structures containing highly toxic materials as defined by Section 307 where the quantity of the material exceeds the maximum allowable quantities of Table 307.1.(2). Aviation control towers, air traffic control centers and emergency aircraft hangars. Buildings and other structures having critical national defense functions. Water treatment facilities required to maintain water pressure for fire suppression.
Site Classification A, B, C, D, E or F based on the types of soil and their engineering properties. Table 1613.5.2 in the IBC 2009 Code Book defines each of the categories in detail. SITE CLASS Note: The IBC specifies Site Class D shall be used when soil properties are unknown. SOIL PROFILE NAME IBC 2009 Table 1613.5.2 SITE CLASS DEFINITIONS AVERAGE PROPERTIES IN TOP 100 FEET, SEE SECTION 1613.5.5 Soil shear wave velocity, v s, (ft/s) Standard penetration resistance, N Soil undrained shear strength, s u, (psf) A Hard Rock v s > 5,000 N/A N/A B Rock 2,500 < v s 5,000 N/A N/A C Very dense soil and soft rock 1,200 < v s 2,500 N > 50 s u 2,000 D Stiff soil profile 600 v s 1,200 15 N 50 1,000 s u 2,000 E Soft soil profile v s < 600 N < 15 s u < 1,000 E -- Any profile with more than 10 feet of soil having the following characteristics: 1. Plasticity index PI > 20, 2. Moisture content w 40%, and 3. Un-drained shear strength s u < 500 psf Any profile containing soils having one or more of the following characteristics: 1. Soils vulnerable to potential failure or collapse under seismic loading such as liquefiable soils, quick and highly sensitive clays, collapsible weakly cemented soils. F 2. Peats and/or highly sensitive clays (H > 10 feet of peat and/or highly organic clay -- where H = thickness of soil) 3. Very high plasticity clays (H > 25 feet with plasticity index PI > 75) 4. Very thick soft/medium stiff clays (H > 120 feet) For SI: 1 foot = 304.8 mm, 1 square foot = 0.0929 m 2, 1 pound per square foot = 0.0479 kpa. N/A = Not applicable
Maximum Spectral Response Acceleration (S s ) Numerical value found using the U.S. Geological (USGS) data based on the Zip Code of the project. This data point can be determined using the Ground Motion Parameter Calculator at http://www.usgs.gov/. Note the calculator assumes a site classification of B for the 0.2 second maximum S s. The site coefficient (F a ), defined below, will correct for the actual site classification. Site Coefficient (F a ) Values ranging from 0.8 to 2.5 determined based on the S s and the Site Classification. Table 1613.5.3(1) in the IBC 2009 Code Book defines these values. IBC 2009 Table 1613.5.3(1) a VALUES OF SITE COEFFICIENT F a SITE MAPPED SPECTRAL RESPONSE ACCELERATION AT SHORT PERIOD CLASS S s 0.25 S s = 0.50 S s = 0.75 S s = 1.00 S s 1.25 A 0.8 0.8 0.8 0.8 0.8 B 1.0 1.0 1.0 1.0 1.0 C 1.2 1.2 1.1 1.0 1.0 D 1.6 1.4 1.2 1.1 1.0 E 2.5 1.7 1.2 0.9 0.9 F Note b Note b Note b Note b Note b a. Use straight-line interpolation for intermediate values of mapped spectral response acceleration at short period, S s. b. Values shall be determined in accordance with Section 11.4.7 of ASCE 7. Component Operating Weight (W p ) This weight term has been removed from the equation below, because EVAPCO is expressing the force in terms of g s and not lbs.
Importance Factor (I p ) - 1.5 for Occupancy Category IV, life safety components required to function after a seismic event or component containing hazardous content. I p = 1.0 for all other components. ASCE 7-05 Section 13.1.3 provides additional detail on importance factors. Importance Factor ( I p ) 1.0 1.5 ASCE 7-05 Section 13.1.3 Component Importance Factor Definition All components shall be assigned a component importance factor of 1.0 that do not follow the conditions of 1.5 (below). If any of the following Conditions Apply: 1. The component is required to function for life-safety purposes after an earthquake, including fire protection sprinkler systems. 2. The component contains hazardous materials. 3. The component is in or attached to an Occupancy Category IV structure and it is needed for continued operation of the facility or its failure could impair the continued operation of the facility. Installation Location (z/h) 0 for units installed at ground level. 1.0 for units installed on a rooftop. Per ASCE 7-05 Section 13.3, z = the component elevation of the point of attachment and h = the relative roof elevation. ASCE 7-05 Section 13.3.1 z/h Definition Z H Elevation in structure of the component attachment point with respect to the base. For components at or below the base, z shall be taken as 0. The value of z/h need not exceed 1.0. Average roof elevation of structure with respect to the base.
APPENDIX B Wind Load Terms, Tables and Figures: Wind Load Factors: Velocity Pressure (q z ) is the wind load the component must withstand (psf). This value takes into account three wind coefficients K, importance factor I, and wind speed V as described below: q z = 0.00256 (K z ) (K zt ) (K d ) (V 2 ) (I) ASCE 07-05 Equation 6-15 Where: Velocity Pressure Exposure Coefficient, K z = 2.01 (z / z g )^(2/α) And where: z is the elevation of the unit above grade (feet) z g is a terrain exposure constant called Nominal Height of the Atmospheric Boundary Layer Found in ASCE 7-05 Table 6-2, based on the Exposure Category found in IBC 2009 1609.4.3. α is a terrain exposure constant called the 3-second Gust-Speed Power Law Exponent. Found in ASCE 7-05 Table 6-2 Togographical Factor, K zt = 1.0 as default when topographical effects are not a factor. Togographical Factor to account for wind speed up effects at hills ridges and escarpments. Wind Directionality Factor, K d = 0.85 for building components. Found in ASCE 7-05 Table 6-4. Basic Wind Speed, V = is the basic wind speed. Found in IBC 2006 Figure 1609. Importance Factor, I Based on ASCE 07-05 Table 6-1, which utilizes occupancy category and wind speed to determine I. = 1.15 for buildings structures that represent a substantial hazard to human life or structures designed as essential facilities. = 1.0 for all other applications where an Evapco unit would be attached.
Basic Wind Speed (V) Numerical value, in miles per hour (mph) found in IBC 2006 Figure 1609. IBC 2009 FIGURE 1609 BASIC WIND SPEED (3-SECOND GUST)
IBC 2009 FIGURE 1609 Cont. BASIC WIND SPEED (3-SECOND GUST)
IBC 2009 FIGURE 1609 Cont. BASIC WIND SPEED (3-SECOND GUST) EASTERN GULF OF MEXICO AND SOUTHEASTERN U.S. HURRICANE COASTLINE IBC 2009 FIGURE 1609 Cont. BASIC WIND SPEED (3-SECOND GUST) WESTERN GULF OF MEXICO HURRICANE COASTLINE
IBC 2009 FIGURE 1609 Cont. BASIC WIND SPEED (3-SECOND GUST) MID AND NORTHERN ATLANTIC HURRICANE COASTLINE Wind Directionality Factor (K d ) 0.85 for building components and cladding as shown in Table 6-4 of ASCE 7-05. Structure Type Buildings Main Wind Force Resisting System Components and Cladding Excerpt From ASCE 7-05 Table 6-4 Wind Directionality Factor K d Directionality Factor K d Structure Classification I, II, III or IV depending on the nature of the building occupancy. Table 1604.5 in the IBC 2009 Code Book defines each of the categories in detail. This is the same as the Occupancy Category used in Seismic calculations (above). 0.85 0.85
Importance Factor (I) Numerical value between 0.77 and 1.15 based on the Basic Wind Speed and the Occupancy Category. These values are found in Table 6-1 of ASCE 07-05. ASCE 7-05 Table 6-1 Importance Factor (I), Wind Loads Category Non-Hurricane Prone Regions and Hurricane Prone Regions with V= 85-100 mph and Alaska Hurricane Prone Regions with V>100 mph I 0.87 0.77 II 1.00 1.00 III 1.15 1.15 IV 1.15 1.15 Ground Surface Roughness B, C or D as defined in Section 1609.4.2 of IBC 2009. Surface Roughness B C D Definition - A ground surface roughness within each 45-degree (0.79 rad) sector shall be determined for a distance upwind of the site as defined in Section 1609.4.3 Urban and suburban areas, wooded areas or other terrain with numerous closely spaced obstructions having the size of single-family dwellings or larger. Open terrain with scattered obstructions having heights generally less than 30 feet (9144 mm). This category includes flat open country, grasslands, and all water surfaces in hurricane-prone regions. Flat, unobstructed areas and water surfaces outside hurricane-prone regions. This category includes smooth mud flats, salt flats and unbroken ice. Exposure Category B, C or D as defined in Section 1609.4.3 of IBC 2009. Exposure Category B C D Definition IBC 2006 Section 1609.4.3 EXPOSURE CATEGORIES Exposure B shall apply where the ground surface roughness condition, as defined by Surface Roughness B, prevails in the upwind direction for a distance of at least 2,600 feet (792 m) or 20 times the height of the building, whichever is greater. Exception: For Buildings whose mean roof height is less than or equal to 30 feet (9144 mm), the upwind distance is permitted to be reduced to 1,500 feet (457m). Exposure C shall apply for all cases where Exposures B or D do not apply. Exposure D shall apply where the ground surface roughness, as defined by Surface Roughness D, prevails in the upwind direction for a distance of at least 5,000 feet (1524 m) or 20 times the height of the building, whichever is greater. Exposure D shall extend into downwind areas of Surface Roughness B or C for a distance of 600 feet (183 m) or 20 times the height of the building, whichever is greater.
Component Elevation (z) The anchorage height of the unit in feet above grade. Nominal Height of the Atmospheric Boundary Layer (z g ) - Numerical value based on Exposure Category. These values are found in Table 6-2 of ASCE 7-05. Excerpt from ASCE 7-05 Table 6-2 TERRAIN EXPOSURE CONSTANTS Exposure α z g (ft) B 7.0 1200 C 9.5 900 D 11.5 700 3 second Gust-Speed power Law Exponent (α) - Numerical value based on Exposure Category. These values are found in Table 6-2 of ASCE 7-05 (above). Velocity Pressure Exposure Coefficient (K z ) A calculated value using the values for z g and α. K z 2.01 z z g 2 Topographic Factor (K zt ) 1.0 default when topographic effects are not a factor. Per ASCE 7-05, wind speed-up effects at hills, ridges and escarpments constituting abrupt changes in topography, located in any exposure category, shall be included in the design when building and other site conditions and locations of structures meet all of the conditions in ASCE 7-05 Section 6.5.7. Velocity Pressure (q z ) This number in pounds per square foot (psf) is calculated using the factors described above. The AT and ESWA are offered with a choice of two structural design packages, consisting of: Standard Structural Design up to 60 psf Upgraded Structural Design up to 145 psf (the maximum value for North America) NOTE: The ATWB Closed Circuit Cooler and ATC-E Evaporative Condensers are certified to 145 psf with standard construction. No additional upgrades are necessary to meet extreme wind loading requirements.