Ord 37-11ORDINANCE NO. 37 -11
AN ORDINANCE OF THE CITY COMMISSION OF THE CITY OF
DELRAY BEACH, FLORIDA, AMENDING THE LAND
DEVELOPMENT REGULATIONS OF THE CODE OF
ORDINANCES, BY AMENDING SECTION 4.5.3, "FLOOD
DAMAGE CONTROL DISTRICTS ", SUBSECTION (D)
"CONSTRUCTION STANDARDS ", TO MODIFY THE SECTION
WHILE MAINTAINING COMPLIANCE WITH STATE STATUTES;
PROVIDING A SAVING CLAUSE, A GENERAL REPEALER
CLAUSE, AND AN EFFECTIVE DATE.
WHEREAS, the National Flood Insurance Program Act (NFIP) was adopted by Congress in
1968; and
WHEREAS, the NFIP enables property owners in participating communities to purchase
insurance protection from the government against losses from flooding; and
WHEREAS, Florida Statutes Section 553.73(5) allows counties and municipalities to adopt by
ordinance an administrative or technical amendment to the Florida Building Code relating to flood
resistance in order.to implement the NFIP or incentives; and
WHEREAS, consistent with 44 C.F.R. §60.6, an administrative amendment may assign the
duty to enforce all or portions of flood- related code provision's to the appropriate agencies of the
local government and adopt procedures for variances and exceptions from flood - related code
provisions other than provisions for structures seaward of the coastal construction control line; and
WHEREAS, the City of Delray Beach desires to modify Section 4.5.3 while maintaining
compliance with NFIP, Federal Emergency Management Act, and the Community Rating System;
and,
WHEREAS, pursuant to LDR Section 1.1.6, the Planning and Zoning Board reviewed the
proposed text amendment at a public hearing held on September 19, 2011 and voted 7 to 0 to
recommend that the changes be approved; and
WHEREAS, pursuant to Florida Statute 163.3174(4)(c), the Planning and Zoning Board,
sitting as the Local Planning Agency, has determined that the change is consistent with and furthers
the goals, objectives and policies of the Comprehensive Plan; and
WHEREAS, the City Commission of the City of Delray Beach adopts the findings in the
Planning and Zoning Staff Report; and
WHEREAS, the City Commission of the City of Delray Beach finds the ordinance is
consistent with the Comprehensive Plan.
NOW, THEREFORE, BE IT ORDAINED BY THE CITY COMMISSION OF THE
CITY OF DELRAY BEACH, FLORIDA, AS FOLLOWS:
Section 1. That the recitations set forth above are incorporated herein.
Section 2. That Article 4.5, "Overlay and Environmental Management Districts ", Section
4.5.3, "Flood Damage Control Districts ", Subsection (D) "Construction Standards" of the Land
Development Regulations of the Code of Ordinances of the City of Delray Beach, Florida, be and the
same is hereby amended to read as follows:
(D) Construction Standards:
(1) General: In all areas of special flood hazard, the following provisions apply:
`n) 4 aaa,
> > udlity ftreas, or afty
All new construction and substantial improvements shall be anchored
to prevent floatation, collapse, or lateral movement of the structure.
(e) All new construction and substantial improvements shall be
constructed with materials and utility equipment resistant to flood
damage.
kc
{d} All new construction or substantial improvements shall be constructed
by methods and practices that minimize flood damage.
4d� {e} All new and replacement water supply systems shall be designed to
minimize or eliminate infiltration of flood waters into the system.
{i} New and replacement sanitary sewage systems shall be designed to
minimize or eliminate infiltration of flood waters into the systems and
discharges from the systems into flood waters.
2 ORD. NO. 37 -11
4D �g} On -site waste disposal systems shall be located to avoid impairment to
them or contamination from them during flooding.
Any alteration, repair, reconstruction, or improvements to a structure
on which the start of construction was begun after May 8, 1978, shall
meet the requirements of new construction as contained in this
chapter.
Manufactured homes shall be anchored to prevent floatation, collapse,
or lateral movement. Method of anchoring may include, but is not
limited to, use of over -the -top or frame ties to ground anchors. This
standard shall be in addition to and consistent with applicable
requirements for resisting wind forces.
15) All mechanical, electrical and plumbing equipment must be located at
or above the BFE. This includes all heaters, air conditioners,
compressors, fans, hot water heaters, laundry facilities, plumbing
fixtures, etc.
.(j� i*J Where enclosed space occurs below the BFE, openings are requited to
allow for automatic entry and exit of flood waters. FEMA requires a
minimum of two (2) openings having a total new area not less than
one (1) square inch per one (1) square foot of enclosed area. All
openings shall be one (1) foot above adjacent grade.
k {�) Louvers, screens, or other opening covers shall not block or impede
the automatic flow of floodwaters into and out of the enclosed areas.
l (m) Openings meeting the requirement of { 0 j- and �) jX above may be
installed in doors. Doors by themselves do not meet the flood venting
requirements.
(2) Mapped Areas: In all areas of special flood hazard where base flood elevation
data has been provided on FEMA Maps, the following provisions apply:
(a) Residential Construction: New construction or substantial
improvement of any residential structure shall have the lowest floor,
(as defined in Appendix "A" to these LDRs), including basement,
elevated to or above base flood elevation.
(b) Nonresidential Construction: New construction or substantial
improvement of any commercial, industrial, or other nonresidential
3 ORD. NO. 37 -11
structure shall either have the lowest floor, (as defined in Appendix
"A" to these LDRs), including basement, elevated to the level of the
base flood elevation or, together with attendant utility and sanitary
facilities, be flood - proofed so that below the base flood level the
structure is watertight with walls substantially impermeable to the
passage of water and with structural components having the capability
of resisting hydrostatic and hydrodynamic loads and effects of
buoyancy.
(3) Subdivisions: All subdivision proposals shall
(a) Be consistent with the need to minimize flood damage;
(b) Have public utilities such as water, gas, sewer, and electrical systems
located and constructed to minimize flood damage;
(c) Have adequate drainage provided to reduce exposure to flood hazards;
(d) Provide base flood elevations in all cases where a plat involves five
acres of land or fifty dwelling units.
Section 3. That should any section or provision of this ordinance or any portion thereof,
any paragraph, sentence, or word be declared by a court of competent jurisdiction to be invalid, such
decision shall not affect the validity of the remainder hereof as a whole or part thereof other than the
part declared to be invalid.
Section 4. That all ordinances or parts of ordinances itl conflict herewith be, and the same
are hereby repealed.
ORD. NO. 37 -11
Section 5. That this ordinance shall become effective immediately upon its passage on
second and final reading. The Clerk shall provide a copy of the adopted ordinance to the Florida
Building Commission within thirty (30) days of passage on second and final reading.
PASSED AND ADOPTED in regular session on seco nd final reading lus the
g o
day of 20-\\_.
ATTEST M A
City Clerk
First Readin �►� ���
Second Readin o�
ORD. NO. 37 -11
:BE::::.:F: , PaiiBeach. Rosf R81rfi &eachRast gain . (5fi1}; &2Q'= 4343;.:
Th �.
Coversheet
MEMORANDUM
TO: Mayor and City Commissioners
FROM: David T. Harden, City Manager
DATE: November 11, 2011
Page 1 of 1
SUBJECT: AGENDA ITEM 10.B. - REGULAR COMMISSION MEETING OF NOVEMBER 15 2011
ORDINANCE NO. 37 -11
ITEM BEFORE COMMISSION
This ordinance is before Commission for second reading of a city- initiated amendment to the Land
Development Regulations (LDRs) that will amend provisions in the Flood Damage Control Districts.
BACKGROUND
At the first reading on November 1, 2011, the Commission passed Ordinance No. 37 -11.
RECOMMENDATION
Recommend approval of Ordinance No. 37 -11 on second and final reading.
http:// itwebapp / Agendalntranet /Bluesheet.aspx ?ItemID =513 3 &MeetinglD =3 3 7 11/21/2011
ORDINANCE NO. 37-11
AN ORDINANCE OF THE CITY COMMISSION OF THE CITY OF
DELRAY BEACI -L FLORIDA, AMENDING THE LAND
DEVELOPMENT REGULATIONS OF THE CODE OF
ORDINANCES, BY AMENDING SECTION 4.5.3, "FLOOD
DAMAGE CONTROL DISTRICTS ", SUBSECTION (D)
"CONSTRUCTION STANDARDS ", TO MODIFY THE SECTION
WHILE MAINTAINING COMPLIANCE WITH STATE STATUTES;
PROVIDING A SAVING CLAUSE, A GENERAL REPEALER
CLAUSE, AND AN EFFECTIVE DATE.
WHEREAS, the National Flood Insurance Program Act (NFIP) was adopted by Congress in
1968; and
WHEREAS, the NFIP enables property owners in participating communities to purchase
insurance protection from the government against losses from flooding and
WHEREAS, Florida Statutes Section 553.73(5) allows counties and municipalities to adopt by
ordinance an administrative or technical amendment to the Florida Building Code relating to flood
resistance in order to implement the NFIP or incentives; and
WHEREAS, consistent with 44 C.F.R. §60.6, an administrative amendment may assign the
duty to enforce all or portions of flood-related code provisions to the appropriate agencies of the
local government and adopt procedures for variances and exceptions from flood-related code
provisions other than provisions for structures seaward of the coastal construction control line, and
WHEREAS, the City of Delray Beach desires to modify Section 4.5.3 while maintaining
compliance with NFIP, Federal Emergency Management Act, and the Community Rating System;
and,
WHEREAS, pursuant to LDR Section 1.1.6, the Planning and Zoning Board reviewed the
proposed text amendment at a public hearing held on September 19, 2011 and voted 7 to 0 to
recommend that the changes be approved; and
WHEREAS, pursuant to Florida Statute 163.3174(4)(c), the Planning and Zoning Board,
sitting as the Local Planning Agency, has determined that the change is consistent with and furthers
the goals, objectives and policies of the Comprehensive Plan; and
WHEREAS, the City Commission of the City of Delray Beach adopts the findings in the
Planning and Zoning Staff Report, and
WHEREAS, the City Commission of the City of Delray Beach finds the ordinance is
consistent with the Comprehensive Plan.
NOW, THEREFORE, BE IT ORDAINED BY THE CITY COMNIISSION OF THE
CITY OF DELRAY BEACH, FLORIDA, AS FOLLOWS:
Section 1. That the recitations set forth above are incorporated herein
Section 2. That Article 4.5, "Overlay and Environmental Management Districts ", Section
4.5.3, "Flood Damage Control Districts ", Subsection (D) "Construction Standards" of the Land
Development Regulations of the Code of Ordinances of the City of Delray Beach, Florida, be and the
same is hereby amended to read as follows:
(D) Construction Standards:
(1) General: In all areas of special flood hazard, the following provisions apply.
flood proofing per FEMAst&-dards.
U �b) All new construction and substantial improvements shall be anchored
to prevent floatation, collapse, or lateral movement of the structure.
b {c) All new construction and substantial improvements shall be
constructed with materials and utility equipment resistant to flood
damage.
Lc) 4 All new construction or substantial improvements shall be constructed
by methods and practices that minimize flood darnage.
Ld) (,e) All new and replacement water supply systems shall be designed to
minimize or eliminate infiltration of flood waters into the system
fe
{49 New and replacement sanitary sewage systems shall be designed to
rAnirnize or eliminate infiltration of flood waters into the systems and
discharges from the systems into flood waters.
ORD. NO. 37 -11
On -site waste disposal systems shall be located to avoid impairrrielt to
them or contamination from them during flooding.
{l� Any alteration, repair, reconstruction, or improvements to a structure
on which the start of construction was begun after May 8, 1978, shall
meet the its of new construction as contained in this
chapter.
lei { Manufactured homes shall be anchored to prevent floatation, collapse,
or lateral movement. Method of anchoring may include, but is not
limited to, use of over - the -top or frame ties to ground anchors. This
standard shall be in addition to and consistent with applicable
requirements for resisting wind forces.
All mechanical, electrical and plumbing equipment must be located at
or above the BFE. This includes all heaters, air conditioners,
compressors, fans, hot water heaters, laundry facilities, plumbing
fixtures, etc.
(j) Where enclosed space occurs below the BFE, openings are required to
allow for automatic entry and exit of flood waters. FEMA requires a
minimum of two (2) openings having a total new area not less than
one (1) square inch per one (1) square foot of enclosed area All
openings shall be one (1) foot above adjacent grade.
lac {}) Louvers, screens, or other opening covers shall not block or injDede
the automatic flow of floodwaters into and out of the enclosed areas.
( )1 (n� Openings meeting the requirement of (W .(j.) and 0) fk) above may be
installed in doors. Doors by themselves do not meet the flood venting
requirements-
(2) Mapped Areas: In all areas of special flood hazard where base flood elevation
data has been provided on FEMA Maps, the following provisions apply.
(a) Residential Construction: New construction or substantial
improvement of any residential structure shall have the lowest floor,
(as defined in Appendix "A" to these LDRs), including basement,
elevated to or above base flood elevation.
(b) Nonresidential Construction: New construction or substantial
improvement of any commercial, industrial, or other nonresidential
ORD. NO. 37 -11
structure shall either have the lowest floor, (as defined in Appendix
"A" to these LDRs), including basement, elevated to the level of the
base flood elevation or, together with attendant utility and sanitary
facilities, be flood-proofed so that below the base flood level the
structure is watertight with walls substantially lmpertneable to the
passage of water and with structural components having the capability
of resisting hydrostatic and hydrodynamic loads and effects of
buoyancy.
(3) Subdivisions: All subdivision proposals shall
(a) Be consistent with the need to minimize flood damage;
(b) Have public utilities such as water, gas, sewer, and electrical systems
located and constructed to minimize flood damage;
(c) Have adequate drainage provided to reduce exposure to flood hazards,
(d) Provide base flood elevations in all cases where a plat involves five
acres of land or fifty dwelling units.
Section 3. That should any section or provision of this ordinance or any portion thereof,
any paragraph, sentence, or ward be declared by a court of competent jurisdiction to be invalid, such
decision shall not affect the validity of the remainder hereof as a whole or part thereof other than the
part declared to be invalid
Section 4. That all ordinances or parts of ordinances in conflict herewith be, and the same
are hereby repealed
Section 5. That this ordinance shall become effective immediately upon its passage on
second and final reading. The Clerk shall provide a copy of the adopted ordinance to the Florida
Building Commission within thirty (30) days of passage on second and final reading.
PASSED AND ADOPTED in regular session on second and final reading on this the
day of , 20.
ATTEST
City Clerk
MAYOR
ORD. NO. 37 -11
First Reading
Second Reading
ORD. NO. 37 -11
Coversheet
MEMORANDUM
TO: Mayor and City Commissioners
FROM: MARK MCDONNELL, AICP, ASST. DIRECTOR PLANNING AND ZONING
PAUL DORLING, AICP, DIRECTOR PLANNING AND ZONING
THROUGH: CITY MANAGER
DATE: October 26, 2011
SUBJECT: AGENDA ITEM 12.A. - REGULAR COMMISSION MEETING OF NOVEMBER 1, 2011
ORDINANCE NO. 37 -11
ITEM BEFORE COMMISSION
Approval of a city- initiated amendment to the Land Development Regulations (LDRs) that will
amend provisions in the Flood Damage Control Districts.
BACKGROUND
On January 11, 2011, Ordinance No. 02 -11 was adopted by City Commission to amend the
Flood Damage Control Districts regulations. The major component of that ordinance (which is
the subject of this text amendment) was to require that the "lowest floor elevation be raised
twelve inches (12') above the Base Flood Elevation (BFE) for all new construction and
substantial improvements in the special flood hazard areas for residential and commercial
structures, mechanical equipment, utility areas, or any enclosed area including basements
and attached garages, or that it must otherwise be provided with flood proofing per FEMA
standards." This recently adopted language has created significant obstacles and has
presented unintended consequences to construction activities. It has further been learned
that while once thought to be mandates from the State that required our Land Development
Regulations to be updated, we now know that the previously adopted amendments were
optional. Accordingly, this text amendment will remove the language that has been
problematic.
REVIEW BY OTHERS
The Planning and Zoning Board reviewed the item at their September 19, 2011 meeting and
a unanimous recommendation of approval was made.
RECOMMENDATION
By motion, approve Ordinance No. 37 -11 on first reading for a city - initiated amendment to
the Land Development Regulations, by adopting the findings of fact and law contained in the
staff report and finding that the amendment is consistent with the Comprehensive Plan and
meets criteria set forth in Section 2.4.5(M) of the Land Development Regulations.
http:// itwebapp/ AgendaIntranet IBluesheet.aspx ?ItemID= 5084 &MeetingID = 335[11/11/2011 12:39:39 PM]
PLANNING AND ZONING BOARD STAFF REPORT
MEETING DATE: SEPTEMBER 19, 2011
AGENDA NO: VI. C.
AGENDA ITEM: CONSIDERATION OF A CITY- INITIATED AMENDMENT TO THE LAND
DEVELOPMENT REGULATIONS (LDR), BY AMENDING SECTION
4.5.3, FLOOD DAMAGE CONTROL DISTRICTS, SUBSECTION D
CONSTRUCTION STANDARDS.
ITEM BEFORE THE BOARD
The item before the Board is to make a recommendation to the City Commission regarding a
city- initiated amendment to the Land Development Regulations (LDRs) that amends provisions
in the Flood Damage Control Districts.
Pursuant to Section 1.1.6, an amendment to the text of the Land Development Regulations may
not be made until a recommendation is obtained from the Planning and Zoning Board.
BACKGROUND /ANALYSIS
Amendments to Section 4.5.3, Flood Damage Control Districts, were recommended by the
Planning and Zoning Board on December 20, 2010 and subsequently approved by City
Commission by Ordinance 02 -11 on January 18, 2011. The purpose was to bring the
regulations into compliance with State requirements. The amendment generally dealt with
mechanical, electrical and plumbing equipment; required openings for enclosed spaces to allow
for flow of floodwaters; and included mention of louvers, screens, door openings and required
dimensions.
However, the major component of the previously adopted ordinance (which is the subject of this
text amendment) was to require that the "lowest floor elevation be raised twelve inches (12 ")
above the Base Flood Elevation (BFE) for all new construction and substantial improvements in
the special flood hazard areas for residential and commercial structures, mechanical equipment,
utility areas, or any enclosed area including basements and attached garages, or that it must
otherwise be provided with flood proofing per FEMA standards." This recently adopted
language has created significant obstacles and has presented unintended consequences to
construction activities. It has further been learned that while once thought to be mandates from
the State that required our Land Developments to be updated, we now know that the previously
adopted amendments were optional. Accordingly, this text amendment will remove only the
language that has been problematic.
Following are the negative effects that have been discovered while implementing the
requirement to raise the lowest floor elevation twelve inches (12 ") above the Base Flood
Elevation (BFE) for all new construction and substantial improvements in the special flood
hazard areas for residential and commercial structures, mechanical equipment, utility areas, or
any enclosed area including basements and attached garages:
■ Storm water cannot be accommodated on -site, due to large allowable building
envelopes and minimal area remaining to accommodate runoff;
Planning and Zoning Board Meeting, September 19, 2011
LDR Amendment — Flood Damage Control Districts
■ Steeper slopes resulting from increased elevation requirements creates erosion
conditions;
■ Negative impacts have occurred to properties adjacent to construction sites;
■ To maintain storm water runoff on -site can require very costly infiltration improvements;
■ Negative impacts have occurred to our public rights -of -way (ponding, erosion); and
■ Construction associated with a higher floor elevation than is actually required, results
with increased costs for fill material, foundation and site stabilization efforts.
This amendment will remove the requirement to raise the lowest floor 12" above the Base Flood
Elevation, while retaining the other components of the code that have value and are beneficial.
Compliance with State requirements will be maintained with adoption of this amendment.
REQUIRED FINDINGS
Comprehensive Plan Conformance
LDR Section 2.4.5(M)(5) (Findings) requires that the City Commission make a finding that the
text amendment is consistent with and furthers the Goals, Objectives and /or Policies of the
Comprehensive Plan. The following were identified as relevant to this amendment:
FLUE Obiective A -1
Property shall be developed or redeveloped, in a manner so that the future use, intensity and
density are appropriate in terms of soil, topographic, and other applicable physical
considerations; encourage affordable goods and services; are complementary to and
compatible with adjacent land uses; and fulfill remaining land use needs.
This objective is supported as new regulations will ensure that development and redevelopment
is appropriate in terms of topographic and other physical considerations, by requiring minimum
elevations for specified features along with openings to allow for the flow of floodwaters.
FLUE Obiective A -5
The City shall maintain its Land Development Regulations, which shall be regularly reviewed
and updated, to provide timely, equitable and streamlined processes including, but not limited
to, building permit processes for residential developments and to accommodate mixed -use
developments, and other innovative development practices.
FLUE Policy A -5.2 The City shall continue to enforce its Flood Damage Protection
Ordinance.
Both Objective A -5 and Policy A -5.2 are supported by the proposed regulations. The objective
requires that the LDRs be regularly reviewed and regularly updated, and the policy requires the
city to enforce its Flood Damage Protection Ordinance.
REVIEW BY OTHERS
Courtesy Notices
Courtesy notices were provided to the following civic associations:
Neighborhood Advisory Council
IF Delray Citizen's Coalition
2
Planning and Zoning Board Meeting, September 19, 2011
LDR Amendment — Flood Damage Control Districts
ALTERNATIVE ACTIONS
A. Continue with direction.
B. Move a recommendation of approval to the City Commission of the amendment to Land
Development Regulations, Section 4.5.3, Flood Damage Control Districts, Subsection
(D) Construction Standards, by adopting the findings of fact and law contained in the staff
report, and finding that the text amendment and approval thereof is consistent with the
Comprehensive Plan and meets the criteria set forth in LDR Section 2.4.5(M)
C. Move a recommendation of denial to the City Commission of the amendment to Land
Development Regulations, Section 4.5.3, Flood Damage Control Districts, Subsection
(D) Construction Standards, by adopting the findings of fact and law contained in the staff
report, and finding that the text amendment and approval thereof is inconsistent with the
Comprehensive Plan and does not meet the criteria set forth in LDR Section 2.4.5(M)
(motion to be made in the affirmative).
RECOMMENDED ACTION
Recommend approval of the amendment to Land Development Regulations, Section 4.5.3,
Flood Damage Control Districts, Subsection (D) Construction Standards, by adopting the
findings of fact and law contained in the staff report, and finding that the text amendment and
approval thereof is consistent with the Comprehensive Plan and meets the criteria set forth in
LDR Section 2.4.5(M).
Attachment:
■ Draft Ordinance
3
Openings in Foundation
Walls and Walls of
Enclosures
Below Elevated Buildings in Special Flood Hazard Areas
in accordance with the National Flood Insurance Program
Technical Bulletin 1 /August 2008
FEMA
are:
s<
i
°F introduction
ctin buildin s that are constructed in special flood hazard areas (SFHAs) from dam-
= Prote g g
age caused b}' flood forces is an important objective of the National ncludel minimum buildingrde-
(NFIP). In support of this objective, the NFIP regal
sign criteria that apply to new construction, repair o£ substanb 3e }'fl flood iesedlttodd buildings, d
substantial improvement o£ existing buildings in SeHAs d }' t d th
SFHAs on Flood Insurance Rate Maps (FIRMS) prepared
flood that has a 1- percent chance of being equaled or exceed-
ed in any given year (commonly called the "100 year" flood).
Certain terms used in this Technical Bulletin are defined in
the Glossary.
ae NFIP. The base floo is e
r der the NFIP, the "low-
floor" is the floor of the est enclosed area of
uilding. An unfinished
or flood- resistant enclo-
The NFIP re uladons rewire that residential buildings sure king of vehicles, lbu�ild r
___ __ _ �ti ing access, or storage Is
r constructed in A zones have the lowest floor (1ncTuc�ng base- parking
to or above the base flood elevation (BI`E) In not the lowest floor, p
this Technical Bulletin, the term rr� zones" 1, AO' and A.Hl�es
ed the enclosure is built in
shown on FIRMS as Zones A, AI;, Al -A30, AR, compliance
quirements.ith applicable
Enclosed areas (enclosures) are permitted under elevated an
buildings provided the enclosed areas meet certain use re- enclosure' is an area that the NFIP,
strictions and construction requirements related to flood is enclosed on all sides by
resistance, inclitding use of flood damage- resistant materials walls.
and installation-of openings to allow for automatic entry and
The NFIP defines a "base -
exit of floodwaters. Enclosures under buildings in V zones rnent" I any area that is
(includes all Zones V, VE, and Vl V30) must meet the salve en- below grade area
all sides.
closure requirements except that openings are not required
and walls nn41st be non - supporting breakaway walls, open rat basement
s Ito extend below
tice -work, or insect screening (see Tech ical Bulletin 9, Design the BFE.
and Construction Guidance for Breakaway Wolfs Below Elevated
Coastal Buildings).
The NFIP regulations £or ncH' aonotruction and,A!u- tatitial owners of existing elevated
t _�__ ___... -_ buildings with enclosures
improvements vements of existing_buildin�s require that enclosed ar-
eas udder elevated non-reside .buildings meet the -same below the BFE may wish
under elevate - _ _ _ to retrofit the enclosures.
rg uirernents as thgse fo�. r onclgsltres_iinder elevated_residen-
tial buildings. New non - residential buildings constructed in A anee rates may apply f the
zones and substantial im-proveinents of existing non -1esin retrofit enclosures have
tial b luhu Idil? s }mist either have their 10INTst floors e�e`�ateci to openings that meet the re-
-_. quirements in this Technical
or aboog the BFE of be floodproofed (made ��'aferti ht} to or Bulletin and also meet other
above the gFE; requirements for enclosures
l\'Iany types of foundations are used to elevate buildings. While algel -rep stantimaterials, and
the main portions of elevated buildings are above the BFI;, elevated utilities).
the Foundation atiod any orcesEn enclosed below
oped areas below Bhe BFE
be exposed to fl
1
TECHNICAL BULLETIN 1 - AUGUST 2008
hiding crawlspaces) are permitted if used only for parking of vehicles, building access,
storage. Figure 1 illustrates a typical crawlspace foundation wall and a typical framed wall
ounding an enclosed area.
If enclosure walls are not designed with openings to relieve the
pressure of standing or slow- moving water against them (called
hydrostatic loads), the walls can be damaged or fail during a
flood. If the walls are "load- bearing" walls that support the el-
evated building, failure of the walls may result in damage to,
or collapse of, the building. To address this concern, the NFIP
regulations require that enclosure walls contain openings that
will allowfor the automatic entry and exit of floodwaters. These
openings allow floodwaters to reach equal levels on both sides
of the walls, thereby lessening the potential for damage caused
by a difference in hydrostatic loads on opposite sides of the
walls. In A zones, the requirement for flood openings applies
to all enclosed areas below new elevated buildings and below
substantially improved buildings.
Areas of shallow flood-
ing may be shown as AO
zones on FIRMs. Rather
than BFEs, AO zones have
"flood depths" that range
from 1 to 3 feet. In these
zones, all NFIP require-
ments related to BFEs
apply, including elevation of
the lowest floor to or above
the designated flood depth
and requirements for enclo-
sures with flood openings
that are located so that
floodwaters will flow in and
out.
This Technical Bulletin explains the NFIP requirements for flood openings and provides
guidance for prescriptive (non- engineered) openings and engineered openings. Non -engi-
neered openings are used to meet the NFIP's prescriptive requirement of I square inch of net
open area for every square foot of enclosed area. As an alternative, engineered openings that
have characteristics that differ from non - engineered openings may be used provided they are
designed and certified by a registered design professional as meeting certain performance
characteristics described in this Technical Bulletin.
Figure 1. Typical enclosures with flood openings
2
TECHNICAL BULLETIN 1 - AUGUST 2008
Framed wall
Joistfiruss
around enclosure
Solid perimeter
'='
(�Crawlspace
foundation wall
(CMU or poured
concrete)
Flood opening
Flood opening
No more than
Interior grade
No more than
Interior grade
1 foot
: °':
1 foot
Exterior grade
¢ `
Exterior grade
Q
a ;p :a:::•Q
Footing depth per
°� • • building code
Figure 1. Typical enclosures with flood openings
2
TECHNICAL BULLETIN 1 - AUGUST 2008