CONTRA COSTA COUNTY, CONTRA COSTA COUNTY FIRE PROTECTION DISTRICT, AND
CROCKETT-CARQUINEZ
FIRE
PROTECTION
DISTRICT
FINDINGS IN SUPPORT OF AMENDMENTS TO THE 2025 CALIFORNIA BUILDING
STANDARDS
CODE,
TITLE
24,
PART
7,
CALIFORNIA
WILDLAND-URBAN INTERFACE
CODE The California Building Standards Commission has adopted and published the 2025 California Wildland-Urban Interface Code. The purpose of this code is to establish minimum requirements to reduce
the
likelihood
of
life
and
property
loss
due
to
a
wildfire
through
the
use
of
performance
and
prescriptive
requirements
for
construction
and
development
in
all
Fire
Hazard
Severity
Zones
in
State
Responsibility
Areas
(SRA),
and
Local
Responsibility
Areas
(LRA)
designated
as
a
Very
High
and
High
Fire
Hazard
Severity
Zone,
increase
the
ability
of
buildings
located
in
any
Fire
Hazard
Severity
Zone
within
State
Responsibility
Areas
(SRA),
Local
Responsibility
Area
(LRA),
or
Wildland-Urban
Interface
(WUI)
Areas
to
resist
the
intrusion
of
flames
or
burning
embers
projected
by
a
vegetation
fire,
and
contribute
to
a
systematic
reduction
in
conflagration
losses
and
reduce
the
likelihood
of
life
and
property
loss
due
to
a
wildfire.
Health and Safety Code section 13869.7, 17958.5, and 18941.5 authorize a local jurisdiction to modify
or
change
the
statewide
codes
and
establish
more
restrictive
building
standards
if
the
jurisdiction
finds
that
the
modifications
and
changes
are
reasonably
necessary
because
of
local
climatic,
geological,
or
topographical
conditions.
Ordinance No. 2025-15 adopts the 2025 California Wildland-Urban Interface Cod e and amends it to
address
local
conditions.
Pursuant
to
Sections
13869.7, 17958.5, and 17958.7 of the Health
and
Safety
Code,
the
Contra
Costa
County
Board
of
Supervisors,
in
its
capacity
as
the
Board
of
Supervisors
and
the
Board
of
Directors
of
the
Contra
Costa
County
Fire
Protection
District
and
the
Crockett-Carquinez
Fire
Protection
District,
finds
that
the
more
restrictive
standards
contained
in
Ordinance
No.
2025-15
are
reasonably
necessary
because
of
certain
local
climatic,
geological,
and
topographic
conditions
that
are
described
below.
Local Conditions A. Climatic 1. Precipitation and Relative Humidity (a) Conditions Precipitation ranges from 15 to 24 inches per year with an average of approximately
20 inches
per
year.
96%
of
precipitation
falls
during
the
months
of
October
through
April
and
four
percent
from
May
through
September.
This
is
a
dry
period
of
at
least
five
months
each
year.
Additionally,
the
area
is
subject
to
occasional
drought.
Relative
humidity
remains
in
the
middle
range
most
of
the
time.
It
ranges
from
45-65%
during
spring,
summer,
fall,
and
from
60-90%
in
the
winter.
It
occasionally
falls
as
low
as
15%.
(b) Impact Locally experienced dry periods cause extreme dryness of untreated wood shakes
and
shingles
on
buildings
and
non-irrigated
grass,
brush,
and
weeds,
which
are
often
near
buildings
with
wood
roofs
and
sidings.
Such
dryness
causes
these
materials
to
ignite
very
readily
and
burn
rapidly
and
intensely.
Because of dryness, a rapidly burning grass fire or exterior building fire can
quickly
transfer
to
other
buildings
by
means
of
radiation
or
flying
brands,
sparks,
and
embers.
A
small
fire
can
rapidly
grow
to
a
magnitude
beyond
the
control
capabilities
of
the
Fire
District
resulting
in
an
excessive
fire
loss.
2. Temperature (a) Conditions Temperatures have been recorded as high as 114° F. Average summer highs
are
in
the
90°
range,
with
average
maximums
of
105°
F.
(b) Impact High temperatures cause rapid fatigue and heat exhaustion of firefighters, thereby
reducing
their
effectiveness
and
ability
to
control
large
building
and
wildland
fires.
Another impact from high temperatures is that combustible building material
and
non-irrigated
weeds,
grass,
and
brush
are
preheated,
thus
causing
these
materials
to
ignite
more
readily
and
burn
more
rapidly
and
intensely.
Additionally,
the
resultant
higher
temperature
of
the
atmosphere
surrounding
the
materials
reduces
the
effectiveness
of
the
water
being
applied
to
the
burning
materials.
This
requires
that
more
water
be
applied,
which
in
turn
requires
more
Fire
District
resources
in
order
to
control
a
fire
on
a
hot
day.
High
temperatures
directly
contribute
to
the
rapid
growth
of
fires
to
an
intensity
and
magnitude
beyond
the
control
capabilities
of
the
Fire
District.
3. Winds (a) Conditions Prevailing winds in the area are from the south or southwest in the mornings
and
from
the
north
or
northwest
in
the
afternoons.
However,
winds
are
experienced
from
virtually
every
direction
at
one
time
or
another.
Velocities
are
generally
in
the
14 mph
to
23 mph
ranges,
gusting
to
25 to
35 mph.
40 mph
winds
are
experienced
occasionally
and
winds
up
to
55 mph
have
been
registered
locally.
During
the
winter
half
of
the
year,
strong,
dry,
gusty
winds
from
the
north
move
through
the
area
for
several
days
creating
extremely
dry
conditions.
(b) Impact
Winds such as those experienced locally can and do cause fires, both interior
and
exterior,
to
burn
and
spread
rapidly.
Fires
involving
non-irrigated
weeds,
grass,
and
brush
can
grow
to
a
magnitude
and
be
fanned
to
intensity
beyond
the
control
capabilities
of
the
Fire
District
very
quickly
even
by
relatively
moderate
winds.
During
wood
shake
and
shingle
roof
fires,
or
exposure
fires,
winds
can
carry
sparks
and
burning
brands
to
other
structures,
thus
spreading
the
fire
and
causing
conflagrations.
When
such
fires
are
not
controlled,
they
can
extend
to
nearby
buildings,
particularly
those
with
untreated
wood
shakes
or
shingles.
In
building
fires,
winds
can
literally
force
fires
back
into
the
building
and
can
create
a
blow
torch
effect,
in
addition
to
preventing
“natural”
ventilation
and
cross-ventilation
efforts.
Winds of the type experienced locally also reduce the effectiveness of exterior
water
streams
used
by
the
Fire
District
on
fires
involving
large
interior
areas
of
buildings,
fires
which
have
vented
through
windows
and
roofs
due
to
inadequate
built-in
fire
protection
and
fires
involving
wood
shake
and
shingle
building
exteriors.
Local
winds
will
continue
to
be
a
definite
factor
towards
causing
major
fire
losses
to
buildings
not
provided
with
fire
resistive
roof
and
siding
materials
and
buildings
with
inadequately
separated
interior
areas
or
lacking
automatic
fire
protection
systems.
National
statistics
frequently
cite
wind
conditions,
such
as
those
experienced
locally,
as
a
major
factor
where
conflagrations
have
occurred.
B. Geological and Topographic 1. Seismicity (a) Conditions Contra Costa County is located in Seismic Risk Zone 4, which is the worst earthquake
area
in
the
United
States.
Buildings
and
other
structures
in
Zone
4 can
experience
major
seismic
damage.
Contra
Costa
County
is
in
close
proximity
to
the
San
Andreas
Fault
and
contains
all
or
portions
of
the
Hayward,
Calaveras,
Concord,
Antioch,
Mt.
Diablo,
and
other
lesser
faults.
A
4.1 earthquake
with
its
epicenter
in
Concord
occurred
in
1958,
and
a
5.4 earthquake
with
its
epicenter
also
in
Concord
occurred
in
1955.
The
Concord
and
Antioch
faults
have
a
potential
for
a
Richter
6 earthquake
and
the
Hayward
and
Calaveras
faults
have
the
potential
for
a
Richter
7 earthquake.
Minor
tremblers
from
seismic
activity
are
not
uncommon
in
the
area.
The fire environment of a community is primarily a combination of two factors:
the
area’s
physical
geologic
characteristics
and
a
historic
pattern
of
urban-suburban
development.
These
two
factors,
alone
and
combined,
create
a
mixture
of
environments
which
ultimately
determines
the
area’s
fire
protection
needs.
The
Fire
District
has
3 distinct
areas.
They
are:
the
West,
which
includes
the
Cities
of
San
Pablo,
Pinole,
and
Hercules
and
the
communities of North Richmond, El Sobrante, and East Richmond Heights:
the
Central,
which
includes
the
Cities
of
Lafayette,
Martinez,
Pleasant
Hill,
Concord,
Walnut
Creek,
Clayton,
and
the
communities
of
Clyde,
Pacheco,
Alhambra
Valley,
and
Alamo;
and
the
East,
which
includes
the
Cities
of
Antioch,
Pittsburg,
Brentwood
and
Oakley
and
the
unincorporated
communities
of
Bay
Point,
Bethel
Island,
Discovery
Bay,
Knightsen,
Byron
and
Marsh
Creek
and
Morgan
Territory.
Because of the size of the Contra Costa County Fire Protection District (733
square
miles),
the
characteristics
of
the
fire
environment
changes
from
one
location
to
the
next.
Therefore
the
District
has
not
one,
but
a
number
of
fire
environments,
each
of
which
has
its
individual
fire
protection
needs
from
two
major
oil
refineries,
to
heavy
industrial
facilities,
freeways,
rail
lines,
waterways,
port
facilities,
wildland
areas,
urban
and
suburban
town
settings,
and
major
downtown
areas.
Interstates 80 and 680, State Highways 4, 24, and 242, Bay Area Rapid Transit
District
(BART),
and
major
thoroughfares
travel
throughout
the
District.
There
are
2 major
rail
lines
which
run
through
the
District.
An
overpass
or
underpass
crossing
collapse
would
alter
the
response
route
and
time
for
responding
emergency
equipment.
This
is
due
to
the
limited
crossings
of
the
major
highways
and
rail
lines.
Earthquakes of the magnitude experienced locally can cause major damage
to
electrical
transmission
facilities,
which,
in
turn,
cause
power
failures
while
at
the
same
time
starting
fires
throughout
the
Fire
District.
The
occurrence
of
multiple
fires
will
quickly
deplete
existing
fire
district
resources;
thereby
reducing
and/or
delaying
their
response
to
any
given
fire.
Additionally,
without
electrical
power,
elevators,
smoke
management
systems,
lighting
systems,
alarm
systems,
and
other
electrical
equipment
urgently
needed
for
building
evacuation
and
fire
control
in
large
buildings
without
emergency
generator
systems
would
be
inoperative,
thereby
resulting
in
loss
of
life
and/or
major
fire
losses
in
such
buildings.
(b) Impact A major earthquake could severely restrict the response of the Fire District and
its
capability
to
control
fires
involving
buildings
of
wood
frame
construction,
with
ordinary
wood
shake
and
shingle
exteriors,
or
with
large
interior
areas
not
provided
with
automatic
smoke
and
fire
control
systems.
2. Soils (a) Conditions
The area is replete with various soils, which are unstable, clay loam and alluvial
fans
being
predominant.
These
soil
conditions
are
moderately
to
severely
prone
to
swelling
and
shrinking,
are
plastic,
and
tend
to
liquefy.
Throughout the Fire District, the topography and development growth has created
a
network
of
older,
narrow
roads.
These
roads
vary
from
gravel
to
asphalt
surface
and
vary
in
percent
of
slope,
many
exceeding
twenty
(20)
percent.
Several
of
these
roads
extend
up
through
the
winding
passageways
in
the
hills
providing
access
to
remote,
affluent
housing
subdivisions.
Many
of
these
roads
are
private
with
no
established
maintenance
program.
During
inclement
weather,
these
roads
are
subject
to
rock
and
mudslides,
as
well
as
down
trees,
obstructing
all
vehicle
traffic.
It
is
anticipated
that
during
an
earthquake,
several
of
these
roads
would
be
practically
impassable.
3. Topographic (a) Conditions (i) Vegetation
The service area of the Contra Costa County Fire Protection District
has
a
varied
topography
and
vegetative
cover.
A
conglomeration
of
flat
lands,
hills,
and
ridges
make
up
the
terrain.
Development
has
occurred
on
the
flat
lands
in
the
District
and
in
the
past
15 years
development
has
spread
into
the
hills,
valleys,
and
ridge
lands
of
the
District.
Highly combustible dry grass, weeds, and brush are common in the hilly
and
open
space
areas
adjacent
to
built-up
locations
six
to
eight
months
of
each
year.
Many
of
these
areas
frequently
experience
wildland
fires,
which
threaten
nearby
buildings,
particularly
those
with
wood
roofs,
or
sidings.
This
condition
can
be
found
throughout
the
Fire
District,
especially
in
those
fully
developed
areas
and
those
areas
marked
for
future
development.
(ii) Surface Features The arrangement and location of natural and manmade surface features,
including
hills,
creeks,
canals,
freeways,
housing
tracts,
commercial
development,
fire
stations,
streets,
and
roads,
combine
to
limit
efficient
response
routes
for
Fire
District
resources
into
and
through
many
areas.
(iii) Buildings, Landscaping and Terrain Many of the “newer” large buildings and building complexes have access
and
landscaping
features
or
designs
which
preclude,
or
greatly
limit,
efficient
approach
or
operational
access
to
them
by
Fire
District
vehicles.
In
addition,
the
presence
of
security
gates,
roads
of
inadequate
width
and
grades
which
are
too
steep
for
Fire
District vehicles create an adverse impact on fire suppression efforts.
When Fire District vehicles cannot gain access to buildings involved
with
fire,
the
potential
for
complete
loss
is
realized.
Difficulty
reaching
a
fire
site
often
requires
additional
fire
personnel
and
resources
to
successfully
and
safely
mitigate
the
event.
Access
problems
often
result
in
severely
delaying,
misdirecting,
or
making
fire
and
smoke
control
efforts
unsuccessful.
(b) Impact The above local geological and topographical conditions increase the magnitude,
exposure,
accessibility
problems,
and
fire
hazards
presented
to
the
Contra
Costa
County
Fire
Protection
District.
Fire
following
an
earthquake
has
the
potential
of
causing
greater
loss
of
life
and
damage
than
the
earthquake
itself.
Hazardous
materials,
particularly
toxic
gases,
could
pose
the
greatest
threat
to
the
largest
number,
should
a
significant
seismic
event
occur.
Public
Safety
resources
would
have
to
be
prioritized
to
mitigate
the
greatest
threat,
and
may
likely
be
unavailable
for
smaller
single
dwelling
or
structure
fires.
Other variables may intensify the situation: 1. The extent of damage to the water system. 2. The extents of isolation due to bridge and/or freeway overpass collapse.
3. The extent of roadway damage and/or amount of debris blocking the
roadways.
4. Climatic conditions (hot, dry weather with high winds). 5. Time of day will influence the amount of traffic on roadways and could
intensify
the
risk
to
life
during
normal
business
hours.
6. The availability of timely mutual aid or military assistance. 7. The large portion of dwellings with wood shake or shingles coverings
could
result
in
conflagrations.
Necessity for More Restrictive Standards Because of the conditions described above, the Contra Costa County Board of Supervisors, in its capacity
as
the
Board
of
Supervisors
and
the
Board
of
Directors
of
the
Contra
Costa
County
Fire
Protection
District
and
the
Crockett-Carquinez
Fire
Protection
District,
finds
that
there
are
building
and
fire
hazards
unique
to
Contra
Costa
County
that
requires
the
increased
fire
protection
requirements
set
forth
in
Ordinance
No.
2025-15.
This ordinance incorporates by adoption of the 2024 International Wildland-Urban Interface Code of the International Code Council (ICC) with necessary California amendments including Chapters 1 – 7 and
Appendix A, Appendix B, Appendix C, Appendix F, Appendix G, and Appendix H as amended by the changes,
additions,
and
deletions
set
forth
in
this
ordinance.