HomeMy WebLinkAboutCERTIFICATION OF ENGINEERED FLOOD OPENINGS FAUG
IVEDR
13Y1 2018
Certification of NA0090lood Openingsy,
t Permitting
In accordance with the Code of Federal Regulations for the National Flood Insurance Program
I hereby certify that the Crawl Space Door Systems flood vents 816CS,1220CS,1232CS,1616CS,1624CS,1632CS,2032CS,2424CS,and 2436CS are
designed in accordance with the requirements of the Code of Federal Regulations for the National Flood Insurance Program(NFIP)
to provide automatic equalization of hydrostatic flood forces by allowing for the entry and exit of floodwaters,when properly installed and sized
as set forth below. Vent opening measurements were measured and certified by Mr.Christopher Mark Loney,Virginia P.E.NO.029000. Detailed
calculations were prepared as outlined In "Review of certification of Engineered Flood Openings," prepared by Dr. Georg Reichard, Associate
Professor of Building Construction,Virginia Tech(available upon request from Crawl Space Door Systems,Inc.billy@crawlspacedoors.com)
Design Characteristics
Section 2.6.2.2 of ASCE/SEI 24-05 provides an equation to determine the required net area of engineered openings (A.)for a given
enclosed area(A.). This equation is based on the hydraulic formula for the flow rate across sharp edged orifices. I have utilized this
equation to calculate 1) the restricted flow rate through the main frame opening in case the louver is blown out during a flood
event; 2) the flow rate through the individual openings between louver blades; and 3) the flow rate through projected openings
between louver blades following hydraulic short-tube'theory. The maximum total enclosed area(A.)that can be serviced by a single
vent has then been determined by utilizing the lowest flow rate of the three assessed scenarios for each vent and is listed in Table 1.
These values are based on the following assumptions:
• In absence of reliable data, the rates of rise and fall have been *) 7 Model H[[in] [in[in2] [ft2]
assumed at a minimum rate of 5 feet/hour; 816CS 8 x 16 105 205
• The (maximum) difference between the exterior and interior ❑ 1220CS 12 x 6 105 50
floodwater levels shall not exceed 1 foot during base flood
conditions; ❑ 1232CS 12 x 32 305 645
• A factor of safety of 5 has been assumed, which is consistent ❑ 1616CS 16 x 16 180 395
with design practices related to protection of life and property; ❑ 1624CS 16 x 24 310 670
• The net area of openings(A.)as provided by the manufacturer. ❑ 1632CS 16 x 32 405 835
❑ 2032CS 20 x 32 630 1240
Installation Requirements and Limitations ❑ 2424CS 24 x 24 570 1230
This certification will be voided if the following installation IEIJ 2436C$ 1 24 x 36 850 1765
requirements and limitations are not enforced:
• There shall be a minimum of two openings on different sides of Table 1 Maximum total enclosed area (Ae) that can be
each enclosed area subject to flooding; serviced by each individual model based on the
• The bottom of all openings shall be no higher than one foot given net area of engineered openings(A.) i
above the higher of the interior or exterior grade that is immediately under each opening;
• No temporary(e.g. during cold weather) or permanent solid cover may be placed into or over the flood vent that would block
the automatic entry orexit of floodwaters at any time;
• Where data or analyses indicate more rapid rates of rise and fall,the required number of openings shall be increased to account
for those different conditions. The number or size of the openings may be decreased if data or analyses indicate rates of rise
and fall are less than 5 feet per hour.
Certifying Design Professional
�II11111/���
Name Steve A.Geci 'title President A. G
Company Geci&Associates Engineers,Inc. �� �'; C' NSF'• %
Address 2950 N 12th Avenue, Pensacola,FL 32503 *;• N0.33658 •�*
License Florid!,--, License No. 33658 AO
STATE OF •��
Signature: Date: i�<`S•r:QR1OP C��IV�`
Ident' atio a iing and Installed Flood Vents (By Others)
The flood vent models marked in Table 1*)are being installed at the following building:
Building Address
Spring 2012 He Copyver.2.0