ASCE 24 - Louver Calc1! RYAN S. HELLWIG, PE ! STRUCTURAL ENGINEER !
January 26, 2011
Re:New Horse Barns
3 County Fairgrounds
41 Fair Street
Northampton, Mass.
LOUVER DESIGN CALCULATION per ASCE 24 - 05 Flood Resistant Design & Construction
Design Flood Elevation DFE = 125 ft
Finished Floor Elevation FFE = 119.6 ft
Table 1-1 Building Classification Category I - Agricultural Facilities
Table 1-1, Footnote a Certain agricultural structures may be exempt from some of the
provisions of this standard - see §C1.4.3
§C1.4.3 Classification of Structures Certain agricultural structures may be constructed with their lowest
floors below the design flood elevation.
§2.6 ENCLOSURES BELOW THE DESIGN FLOOD ELEVATION
§2.6.2 Design of Openings Openings shall meet the non-engineered requirements of §2.6.2.1 or
the engineered opening requirements of §2.6.2.2
§2.6.2.2 Engineered Openings Engineered Openings shall meet the following criteria:
1.Each individual opening, and any louvers...shall be designed to allow automatic entry and exit of floodwaters during design
flood or lesser flood conditions;
2.There shall be a minimum of two openings on different sides of each enclosed area;
3.Openings shall not be less than 3" in any direction in the plane of the wall;
4.The bottom of each required opening shall be no more than 1 ft. above the adjacent ground level;
5.The difference between exterior and interior floodwater levels shall not exceed 1 ft;
6.In the absence of reliable data on rates of rise and fall, assume a minimum rate of rise and fall of 5 ft/h;
7.The minimum total net area of the required openings in non-breakaway enclosure walls shall be calculated using the
equation:
o eA = 0.033 (1/c) (R) (A )
oA = the total net area of openings required (in )2
c = opening coefficient of discharge = 0.35 for square, unobstructed
R = worst case rate of rise and fall (ft/h) = 5 ft/h assumed
eA = the total enclosed area (ft ) = 19,000 ft per barn22
oA = 0.033 (1/0.35) (5) (19,000) = 8,960 in REQUIRED2
oA = (16) (0.45) (36) = 9331 in PROVIDED - Sixteen 36"x36" louvers with 45% free area22
o oA PROVIDED > A REQUIRED ” OK
! 28 ALDRICH STREET ! NORTHAMPTON, MA 01060 !
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