HomeMy WebLinkAboutOrdinance 2136 N.C.S. 09/09/20021
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0CT172002 �1
Introduced by
Councilmember Maguire
ORDINANCE NO.2136 N.C.S.
Seconded by
Councilmember Cader-Thompson
AN ORDINANCE OF THE COUNCIL OF THE CITY OF PETALUMA REPEALING
CHAPTER 17.04 OF THE PETALUMA MUNICIPAL CODE AND ADOPTING NEW
CHAPTER 17.04 TO ADOPT BY REFERENCE THE FOLLOWING CODES:
CALIFORNIA BUILDING STANDARDS TITLE 24, PART 2, 2001 CALIFORNIA
BUILDING CODE, INCORPORATING THE UNIFORM BUILDING CODE, 1997
EDITION, INCLUDING CERTAIN APPENDICES; UNIFORM HOUSING CODE, 1997
EDITION; DWELLING CONSTRUCTION UNDER THE UNIFORM BUILDING CODE,
1997 EDITION; UNIFORM CODE FOR THE ABATEMENT OF DANGEROUS
BUILDINGS, 1997 EDITION; UNIFORM ADMINISTRATIVE CODE, 1997 EDITION;
UNIFORM BUILDING SECURITY CODE, 1997 EDITION; UNIFORM SIGN CODE,
1997 EDITION; DWELLING CONSTRUCTION UNDER THE UNIFORM
MECHANICAL CODE, 1997 EDITION; 1997 ANALYSIS OF REVISIONS TO THE
UNIFORM BUILDING CODES; CALIFORNIA BUILDING STANDARDS TITLE 24,
PART 4, 2001 CALIFORNIA MECHANICAL CODE, INCORPORATING THE
UNIFORM MECHANICAL CODE, 2000 EDITION; CALIFORNIA BUILDING
STANDARDS TITLE 24, PART 5, 2001 CALIFORNIA PLUMBING CODE,
INCORPORATING THE UNIFORM PLUMBING CODE, 2000 EDITION;
UNIFORM SWIMMING POOL, SPA AND HOT TUB CODE, 1997 EDITION;
UNIFORM SOLAR ENERGY CODE, 1997 EDITION; CALIFORNIA
BUILDING STANDARDS TITLE 24, PART 3, 2001 CALIFORNIA ELECTRICAL
CODE, INCORPORATING THE NATIONAL ELECTRICAL CODE, 1999
EDITION; CALIFORNIA BUILDING STANDARDS TITLE 24, PART 10, 2001
CALIFORNIA CONSERVATION CODE, INCORPORATING APPENDIX
CHAPTER 1 OF THE 1997 UNIFORM CODE FOR BUILDING CONSERVATION
BE IT ORDAINED BY THE COUNCIL OF THE CITY OF PETALUMA AS FOLLOWS:
43 SECTION 1. REPEAL OF OLD BUILDING CODES.
44 Chapter 17.04 of the Petaluma Municipal Code, entitled "Uniform Codes for Construction and
45 Regulation of Buildings and Structures" is hereby repealed in its entirety.
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Ordinance 2136 N.C.S. Page 1.
I SECTION 2. FINDINGS.
2 The City Council of the City of Petaluma finds that in order to best protect the health, safety and
3 welfare of the citizens of the City of Petaluma, the standards of building within the City must
4 conform with state law except where local conditions warrant more restrictive regulations, and,
5 therefore, the City Council should adopt the current state building codes, contained in California
6 Building Standards Title 24, and other uniform codes governing the construction and regulation
7 of buildings and structures.
8
9 Pursuant to California Health and Safety Code section 17958.7, the City Council makes the
10 factual findings set forth in "Exhibit A" attached hereto and incorporated herein by reference,
11 and finds that the amendments made in this ordinance to the California Building Standards Title
12 24, Part 2, 2001 California Building Code, incorporating the Uniform Building Code, 1997
13 Edition, are reasonably necessary because of the local climatic, geological or topographical
14 conditions.
15
16 SECTION 3. CURRENT BUILDING CODES ADOPTED.
17 Chapter 17.04 of the Petaluma Municipal Code, entitled "Uniform Codes for Construction and
18 Regulation of Buildings and Structures" is hereby added to read as follows:
19
20 17.040.010 Adopt Uniform Codes.
21 Pursuant to Section 50022.2 of the California Government Code, the following
22 codes are adopted by reference, including the amendments listed in this chapter,
23 which are made pursuant to the findings of fact set forth in the adopting
24 ordinance.
25 A. California Building Standards Title 24, Part 2, 2001 California Building
26 Code, incorporating the Uniform Building Code, 1997 Edition, Volumes
27 1, 2, and 3, as adopted and published by the International Conference of
28 Building Officials, including all appendices except Volume 1 Appendix
29 Chapter #4, Barriers For Swimming Pools, Spas and Hot Tubs; Volume 1
30 Appendix Chapter #11, Accessibility; and Volume 1 Appendix Chapter
31 #30 Elevators, Dumbwaiters, Escalators and Moving Walks (hereinafter
32 "Uniform Building Code" or "UBC"); except as amended in section
33 17.04.020 below.
34 B. Uniform Housing Code, 1997 Edition, as the same is adopted and
35 published by the International Conference of Building Officials.
36 C. Dwelling Construction Under the Uniform Building Code, 1997 Edition,
37 as the same is adopted and published by the International Conference of
38 Building Officials.
Ordinance 2136 N.C.S.
Page 2
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D.
Uniform Code for the Abatement of Dangerous Buildings, 1997 Edition,
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as the same is adopted and published by the International Conference of
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Building Officials.
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E.
Uniform Administrative Code, 1997 Edition, as the same is adopted and
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published by the International Conference of Building Officials.
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F.
Uniform Building Security Code, 1997 Edition, as the same is adopted
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and published by the International Conference of Building Officials.
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G.
Uniform Sign Code, 1997 Edition, as the same is adopted and published
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by the International Conference of Building Officials, except Section 303
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is omitted.
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H.
Dwelling Construction under the Uniform Mechanical Code, 1997
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Edition, as published by the International Conference of Building
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Officials.
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I.
1997 Analysis of Revisions to the Uniform Building Codes as the same is
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adopted and published by the International Conference of Building
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Officials.
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J.
California Building Standards Title 24, Part 4, 2001 California
18
Mechanical Code, incorporating the Uniform Mechanical Code, 2000
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Edition, as the same is adopted and published by the International
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Conference of Plumbing and Mechanical Officials.
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K.
California Building Standards Title 24, Part 5, 2001 California Plumbing
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Code, incorporating the Uniform Plumbing Code, 2000 Edition, as the
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same is adopted and published by the International Association of
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Plumbing and Mechanical Officials.
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L.
Uniform Swimming Pool, Spa and Hot Tub Code, 1997 Edition, as the
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same is adopted and published by the International Association of
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Plumbing and Mechanical Officials.
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M.
Uniform Solar Energy Code, 1997 Edition, as the same is adopted and
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published by the International Association of Plumbing and Mechanical
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Officials.
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N.
California Building Standards Title 24, Part 3, 2001 California Electrical
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Code, which incorporates the National Electrical Code, 1999 Edition, as
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adopted and published by the National Fire Protection Association.
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O.
California Building Standards Title 24, Part 10, 2001 California
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Conservation Code, which incorporates Appendix Chapter 1 of the 1997
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Uniform Code for Building Conservation, as published by the
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International Conference of Building Officials.
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All references to permit fees are hereby deleted. The permit fees shall be fixed by
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the Fee Schedules adopted by the City Council by Resolution.
41
Ordinance 2136 N.C.S. Page 3
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17.04.020 Amendments Made in Uniform Building Code.
The Uniform Building Code, as adopted in section 127.04.010, is hereby
amended to include the following additions, amendments and deletions:
1. Section 106.2, Exemption #5 is amended to read as follows:
Retaining walls which are not over two (2) feet in height measured
from top of the footing to the top of the wall, unless supporting a
surcharge,. or impounding flammable liquids.
Property line retaining walls may be of all heart redwood up to
two (2) feet in height; property line retaining walls up to four (4) feet shall
be of pressure treated lumber; property line retaining walls over four (4)
feet to be engineered.
On -site retaining walls up to four (4) feet may be of all heart
redwood or pressure rated; over four (4) feet walls shall be engineered and
set back a minimum distance equal to the height of the wall from the
property line or foundation of the building.
Heights of walls are measured from the bottom of finished board
or top of footing to top of finished board.
2. Section 106.4.4 is hereby added to read as follows:
106.4.4. Definition of `Abandoned':
Work shall be considered abandoned if an inspection has not
been recorded and approved within 180 days.
3. Section 107.5.1.2 is hereby added to read as follows:
(a) A Stop Work Order will be issued when:
1) Work is being done or has been done without a permit.
2) Work being done is beyond the scope of the issued permit.
3) Work being done does not match approved plans.
4) Work being done violates current adopted Building Code.
5) Work being done in violation of Municipal Code and
Zoning Ordinance.
(b) Violators receiving a Stop Work Order are required to respond to
the Building Division within 48 hours of the issued notice to
receive instructions on how to rescind the order. If no response is
forthcoming, within 48 hours, the Building Division will forward a
Building Code Violation memo to the City Attorney's Office for
abatement action. A copy of the abatement request will be sent to
the Planning Department for their use and information.
Ordinance 2136 N.C.S.
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(c) A building permit application with construction plans and
supporting (structural calculations, energy calculations,
handicapped access) documents must be submitted for approval
within 15 working days following response to the Building
Division. Plans will be reviewed within 15 working days and a
correction letter issued or permit application approved. A
response to any correction letter must be returned within 15
working days. Five working days will be required to review this
second submission and a permit approved for issue. Permits ready
for issue must be issued within 5 working days. All construction
must be inspected as work progresses and signed off by all
(affected) departments within 60 days of building permit issuance.
(d) All time limitations for plan check review and construction
indicated in the building codes shall not apply to any work
indicated in Section (a) that has received a Stop Work Order.
(e) An additional fee of double the permit fee shall be added to each
permit reflecting a Stop Work Order.
4. Section 207 is hereby amended to read as follows:
207 Definition
"Fully sprinklered building -- residential" is added to read as
follows: FULLY SPRINKLERED BUILDING RESIDENTIAL --
shall mean the installation of automatic fire sprinklers in attics,
garages, (attached or not) and other unprotected spaces in addition
to any other fire sprinkler system required for residential
structures.
5. Section 214 is hereby amended to read as follows:
214 Definition
"Multi -Family Dwelling" is added to read as follows:
MULTI -FAMILY DWELLING -- Any structure containing more
than one living unit or designed to be occupied by more than one
family unit. This definition is applicable only as it relates to the
installation of a fire sprinkler system.
Ordinance 2136 N.C.S.
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6. Section 904.1.1 is hereby added to read as follows:
904.1.1 General
An automatic fire extinguishing system shall be installed in
the occupancies and locations as set forth in this section.
7. Sections 904.1.2 and 904.1.2.1 are hereby added to read as follows:
904.1.2 Standards
Fire extinguishing systems shall comply with the National
Fire Protection Association and/or Petaluma City Fire
Department standards. When conflicts occur between
NFPA and local standards, the local standards shall prevail.
904.1.2.1 Uniform Building Code standards for sprinklers and
standpipes.
Where the Uniform Building Code standards 9-1 and 9-3
(automatic fire sprinkler systems) and 9-2 (standpipe
systems) are referenced in this code, substitute the current
edition of NFPA 13, 13D, 13R, and 14 respectively.
8. Sections 904.2.1, 904.2.1.1, 904.2.1.2, 904.2.1.3, 904.2.1.4, 904.2.1.5, 904.2.1.6
and 904.2.9 are hereby added to read as follows:
904.2.1 Fire Extinguishing Systems (sprinklers) in Commercial
Buildings Required.
Commencing on or after July 1, 1999, all commercial
buildings or structures for which building permits are
submitted shall have an approved fire sprinkler system.
Exception: Buildings which do not exceed 1000 square
feet and present no exposure hazard to other structures.
904.2.1.1 Existing Commercial Buildings
Required throughout all existing commercial buildings
which are added to and:
1. Increases the original square footage by 25%, or
2. Causes the structure to exceed 24 feet in height at
any point.
Ordinance 2136 N.C.S.
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904.2.1.2 Change of Occupancy
In all buildings or tenant spaces where a change of
occupancy results in an increased hazard classification to
the building or tenant space as defined in table 3-A of the
UBC, 1997 edition.
904.2.1.3 Destroyed by Fire
In all existing commercial buildings where fire burns more
than 50% of the structure as determined by the Fire
Marshal and Building Official
904.2.1.4 Lot Splits
In all existing structures on land parcels that are split or
subdivided where emergency vehicle access, water supply,
grade(s), or other conditions exist which do not meet Fire
Code or City standards.
904.2.1.5 Annexations into the City of Petaluma. In all existing
commercial structures which are annexed to the city when:
1. The occupancy use of the building which increase
the fire hazard and/or is a hazardous occupancy, as
defined in Table 3-A of the UBC 1997 edition, or
2. The building square footage is 3500 square feet or
more.
904.2.1.6 Design Criteria
Fire sprinkler systems installed in buildings of
undetermined use shall be designed and installed to have a
design density of (.33) gallons per minute per square foot
over a minimum design area of 3000 square feet. Where a
subsequent occupancy change requires a system with
greater capacity, it shall be the building owners'
responsibility to upgrade the system to the required density
and meet any additional requirements of the Fire Code at
the time of such change.
904.2.9 Group R, Division 1 Occupancies and Multi -Family
Dwellings.
An automatic sprinkler system shall be installed throughout
every apartment house and multi -family dwelling.
Ordinance 2136 N.C.S.
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Residential or quick response standard sprinklers shall be
used in the dwelling units' guest room portions of the
building.
9. Sections 904.2.9.1, 904.2.9.2, 904.2.9.3 and 902.2.9.4 are hereby added to read as
follows:
904.2.9.1 Residential Fire Extinguishing System Required After July
1, 2000.
Commencing on or after July 1, 2000, all single family
dwellings for which a building permit is submitted shall
require a residential fire extinguishing system designed in
accordance with NFPA 13 "D".
9042.9.2 Residential Fire Extinguishing System Fully Sprinklered
— Requirements.
Full sprinkler systems are required in all newly constructed
single-family dwellings that meet any one of the following
conditions (residential — see definition, Section 207).
1. Fire flows of 1000 GPM or less where the residual
pressure is 30 PSI or less.
2. Three or more stories in height.
3. Located within the boundaries of the Very High
Fire Hazard Severity Zone.
4. Are located at elevations or in areas where the
water supply does not meet fire flow requirements
as determined by the fire chief.
5. Are located more than 150 feet from an approved
all weather emergency vehicle access.
6. Are located where access is hampered by
insufficient road widths, excessive grades, lack of
adequate turnarounds, or other conditions which
would impede or delay emergency response
vehicles.
7. In the opinion of the chief, create an increased
hazard or condition that will hamper the ability of
fire suppression crews to adequately suppress a fire
and/or affect firefighter safety.
Ordinance 2136 N.C.S.
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10.
904.2.9.3 Residential Type Sprinkler Heads.
Fire sprinklers installed in residential occupancies shall be
approved and listed quick response type heads in living and
sleeping areas.
904.2.9.4 Residential Conversions and Additions
Fire sprinkler systems shall be installed in all single-family
dwellings that are converted to duplexes and/or multi-
family dwellings, bed and breakfasts, inns, lodging houses,
or similar uses (see multi -family family definitions, Section
207). All additions in residences with an existing sprinkler
system shall require the extension of the sprinkler system
into the addition. Exiting residences in which an addition
occurs and no fire sprinkler system has been previously
installed will not require installation of a sprinkler system
in either the existing structure or the addition.
Sections 904.5.2.1 and 904.5.2.2 are hereby added to read as follows:
904.5.2.1 Mid -Rise Combination Standpipes
Every mid -rise building shall be provided with an approved
combined standpipe system. A combined standpipe system
is one in which the water piping serves the required 2'/2-
inch (63.5 mm) outlets for Fire Department use and the
outlets for the automatic fire sprinkler system. The
combined standpipe system shall be capable of not less
than 500 gpm (1893 Lpm) for the first standpipe plus 250
gpm (946 Lpm) for each additional standpipe and the
sprinkler demand need not be added. A residual pressure of
100psi at the topmost outlet of each standpipe shall be
maintained. The maximum water supply need not exceed
1500 gpm (5678 Lpm). Street water mains may be used as
the supply and on -site water supplies are not required,
unless the street water mains cannot supply the demand.
904.5.2.2 Standpipe Modifications
Standpipe requirements of Section 904.5.2 (Referencing
Table 9-A) in buildings three or more stories in height may
be modified and otherwise required, if in the opinion of the
Building Official, a hazard or condition exists in which the
Ordinance 2136 N.C.S.
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installation of standpipes would improve firefighting
operations.
11. Section 1503 is hereby amended to read as follows:
1503 All materials applied as roof covering for reroofing shall have a
fire rating of Class `B' or better; material in accordance with UBC
Standard 15-2.
12. Appendix Section 1514 is hereby amended to read as follows:
Appendix Section 1514. Reroofing.
All materials applied as roof covering for reroofing shall have a fire rating
of Class "B" or better; material in accordance with UBC Standard 15-2.
13. Section 1701.5 is hereby amended to read as follows:
Per all new construction, prior to close in inspection a third -party special
seismic inspector may, in the discretion of the building official, be
employed to inspect every aspect of the structural system, i.e., all elements
of the load path.
14. Section 1804.8 is hereby amended to read as follows:
1804.8 Crawl Space Grade and Drainage.
Foundation walls shall have a 3" (minimum) diameter
through wall pipe to conduct underfloor water to the
outside of the building. Underfloor area shall be graded to
the through -wall pipe and exterior grading shall be sloped
away from the building.
Grade level in underfloor areas shall not be lower than
exterior grade unless adequate drainage to as positive
outfall is provided. Where any water will collect in the
underfloor area, an approved drainage system shall be
provided.
Ordinance 2136 N.C.S.
Page 10
1 15. Section 2310 is hereby amended to read as follows:
2
3 Section 2310. All roof covering materials applied as exterior all covering
4 shall have a fire rating of Class " B" or better, in accordance with UBC
5 Standard 15-2.
6
7 17.04.030 Copies made available.
8 The city clerk shall retain three copies of each code adopted in Section 17.04.010
9 of this chapter, and keep the same on file in the office of said city clerk for the
10 examination of the public, but such codes shall not be deemed invalid because of
11 the omission to have copies on file at any time.
12
13 17.04.040 Amendments -- State Commission of Housing and Community
14 Development.
15 All amendments to the codes mentioned in Section 17.04.010 which have been
16 duly adopted by regulation or act of the California Commission of Housing and
17 Community Development shall be deemed to be a part of the code so amended,
18 whether said regulation is effective upon the effective date of this section or
19 thereafter.
20
21 SECTION 4. The City Clerk is hereby directed to file this ordinance and the attached findings
22 of fact, with the California Department of Housing and Community Development.
23
24 SECTION 5. All former ordinances or parts thereof conflicting or inconsistent with the
25 provisions of this ordinance or of the Code or Standards hereby adopted are hereby repealed.
26
27 SECTION 6. If any section, subsection, sentence, clause or phrase or word of this ordinance is
28 for any reason held to be unconstitutional, unlawful or otherwise invalid by a court of competent
29 jurisdiction, such decision shall not affect the validity of the remaining portions of this
30 ordinance. The City Council of the City of Petaluma hereby declares that it would have passed
31 and adopted this ordinance and each and all provisions thereof irrespective of the fact that any
32 one or more of said provisions be declared unconstitutional, unlawful or otherwise invalid.
33
34 SECTION 7. This ordinance shall become effective thirty (30) days after the date of its
35 adoption by the Petaluma City Council, or on November 1, 2002, whichever is later.
36
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Ordinance 2136 N.C.S. Page 11
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SECTION 8. The City Clerk is hereby directed to post this ordinance for the period and in the
manner required by the City Charter.
INTRODUCED and ordered posted/ this 9th day of September, 2002.
ADOPTED this 17th day of September, 2002 by the following vote:
AYES: Cader-Thompson, Vice Mayor Healy, Maguire, Moynihan, O'Brien,
Mayor Thompson, Torliatt
NOES: None
ABSENT: None
E. ClarVtrhompson, Mayor
ATTEST: APP-RO-V-ED--A5- T0-EORM:
Gay/Ile Peter en, City Clerk Rich rd Rudnansky, City A
a
Ordinance 2136 N.C.S.
Page 12
EXHIBIT "All
FINDINGS OF FACT AND NEED FOR CHANGES OR MODIFICATIONS
TO THE CALIFORNIA BUILDING STANDARDS TITLE 24,
PART 2, CALIFORNIA BUILDING CODE, INCORPORATING
THE UNIFORM BUILDING CODE, 1997 EDITION
CHANGES OR MODIFICATIONS: Pursuant to Section 17958 of the State of California Health
and Safety Code, the governing body of the City of Petaluma in its ordinance adopting, and
amending the California Building Standards Title 24, Part 2, California Building Code,
incorporating the Uniform Building Code, 1997 Edition, changes or modifies certain provisions
of the State Building Standards Code as it pertains to the regulation of buildings used for human
habitation. A copy of the text of such changes or modifications is attached.
FINDINGS: Pursuant to Sections 17958.5 and 17958.7 (a) of the State of California Health and
Safety Code, the governing body of the City of Petaluma has determined and finds that all the
attached changes or- modifications are needed and are reasonably necessary because of local
climatic, geological and topographic conditions as discussed below.
LOCAL CONDITIONS: Local conditions have an adverse effect on the prevention of (1) major
loss fires, (2) major earthquake damage, and (3) the potential for life and property loss, making
necessary changes or modifications in the Uniform Fire Code and the State Building Standards
Code in order to provide a reasonable degree of property security, and fire and life safety in the
City of Petaluma.
Below are listed adverse local climatic, geological and topographic conditions.
CLIMATIC
Precipitation: Precipitation ranges from 20 inches to approximately 25 inches per year.
Approximately ninety percent (90%) falls during the months of November through April, and
10% from May through October. In 1994-1995, severe flooding occurred during the months of
January and March 1995 and 1998.
Relative Humidity: Humidity generally ranges from 50% during daytime 86% at night. It drops
to 20% during the summer months and occasionally drops lower during the months of September
through November.
Temperatures: Temperatures have been recorded as high as 104 degrees Fahrenheit. Average
summer highs are in the 78-85 degree range
Winds: Prevailing winds are from the northwest. However, winds are experienced from virtually
every direction at one time or another. Velocities are generally in the 5-15 mph range, gusting to
Exhibit A
Page l of 3
7.4-30 mph, particularly during the summer months. Extreme winds, up to 50 mph, have been
known to occur.
Summary: These local climatic conditions affect the acceleration intensity, and size of fire in the
community. Times of little or no rainfall, of low humidity and high temperatures create
extremely hazardous conditions, particularly as they relate to wood shake and shingle roof fires
and conflagrations. The winds experienced in this area can have a tremendous impact upon
structure fires in buildings in close proximity to one another. Winds can carry sparks and burning
brands to other structures, thus spreading the fire and causing conflagrations. In building, fires,
winds can literally force fires back into the building and create a blowtorch effect, in addition to
preventing "natural" ventilation and cross -ventilation efforts.
GEOLOGICAL AND TOPOGRAPHIC
The fire environment of a community is primarily a combination of two factors: the area's
physical geographic characteristics and the historic pattern of urban -suburban development.
These two factors, alone and combined, create a mixture of environments which ultimately
determine the areas' fire protection needs.
The basic geographical boundaries of the city include hills to the south and west, and valley floor
in the central area and to the north and east. The Petaluma River bisects the city through the
central area. Because of the size of the City of Petaluma (12 square miles), the characteristics of
the fire environment changes from one location to the next. Therefore the city has not one, but a
number of, fire environments; each of which has its individual fire protection needs.
The service area of the City of Petaluma has a varied topography and vegetative cover. A
conglomeration of bay, plains, hills and ridges make up the terrain. Development has occurred
on the flat lands in the central and eastern portions of the city. However, over the last ten years,
development has spread into the hills and the smaller valleys and canyons.
Seismic Location: The relatively young geological processes that have created the San Francisco
Bay Area are still active today. Two active earthquake faults (San Andreas and the Healdsburg-
Rodgers Creek) affect the Petaluma area. Approximately 50% of the city's land surface is in the
high -to -moderate seismic hazard zones.
Size and Population: The City of Petaluma covers 12 square miles including an urban
population estimated at 50,000. Within the city are three (3) fire stations and a total of 53 fire
personnel. The Fire Department handles diverse responsibilities including wild land and urban
fires, freeway, air, rail and medical emergencies.
Topography: The city's service area is a conglomeration of bay plains, hills, valleys, and ridges.
The flatter lands are found in the central and eastern portions of the city. Most of the existing
urban and suburbanized areas are on relatively flat lands (O 5%) slope.
Future residential development is also proposed for the hill areas south and west of the city. The
majority of the hillsides in these areas have slopes ranging from 15 - 30%. Correspondingly,
there is much diversity in slope percentages. Slope is an important factor in fire spread. As a
Exhibit A
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basic rule of thumb, the rate of spread will double as the slope percentage doubles, all other
factors remaining the same.
Vegetation: Petaluma's semi -arid Mediterranean -type climate produces vegetation similar to that
of most of Sonoma County.
Approximately half of all the structures in the city have combustible wood -shingle or shake
roofs. This very flammable material is susceptible to ignition by embers from a wild land fire,
furthering the spread of fire to adjacent buildings.
Summary: The above local geological and topographic conditions enhance the magnitude,
exposure, accessibility problems, and fire hazards presented to the City of Petaluma. Fire
following an earthquake has the potential of causing greater loss of life and damage than the
earthquake itself.
The majority of the City's industrial complexes are located in the highest seismic risk zones. The
highest seismic risk zone also contains the largest concentration of hazardous materials.
Hazardous materials, particularly toxic gases, could pose the greatest threat to the largest
number, should a significant seismic event occur. The City's resources would have to be
prioritized to mitigate the greatest threat, and may likely be unavailable for fires in smaller
single -dwellings and structures.
Other variables may tend to intensify the situation:
The extent of damage to the water system, the extent of isolation due to bridge and/or freeway
overpass collapse, the extent of roadway damage and/or amount of debris blocking the roadways,
climatic conditions (hot, dry weather with high winds); time of day will influence the amount of
traffic on roadways and could intensify the risk of life during normal business hours.
The availability of timely mutual aid or assistance from neighboring departments, which could
also have emergencies at the same time. The large portion of dwellings with wood shingle roof
coverings could result in conflagrations.
CONCLUSION
Local climatic, geological and topographic conditions impact fire protection efforts, and the
frequency, spread, acceleration, intensity and size of fire involving buildings in this community.
Further, they impact potential damage to all structures from earthquake and subsequent fire.
Therefore it is found to be reasonably necessary that the Uniform Fire Code be changed or
modified to mitigate the effects of the above conditions.
Exhibit A
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