(Amended by Ord. No. 187,719, Eff. 1/23/23.)
Chapter 3 of the CRC is adopted by reference except for the following Sections are not adopted: R301.1.3, R301.1.3.2, R301.2.2.6, R311.2, R313.1, R313.2, R321.1, R321.2, R322.1.4.1, and Table R301.2(1); and the following LAMC Sections are added: 91.5.301.1.3, 91.5.301.1.3.2, 91.5.301.1.5, 91.5.301.2.2.6, 91.5.301.2.2.11, 91.5.311.2, 91.5.313.1, 91.5.313.2, 91.5.321.1, 91.5.321.2, 91.5.322.1.4.1, and Table R301.2(1).
91.5.301.1.3. Engineered Design. (Amended by Ord. No. 186,488, Eff. 12/27/19.) Where a building of otherwise conventional construction contains structural elements exceeding the limits of CRC Section R301 or otherwise not conforming to this Code, these elements shall be designed in accordance with accepted engineering practice. The extent of such design need only demonstrate compliance of nonconventional elements with other applicable provisions and shall be compatible with the performance of the conventional framed system. Engineered design in accordance with the Los Angeles Building Code is permitted for all buildings and structures, and parts thereof, included in the scope of this Code.
Buildings with masonry or concrete walls or of light frame construction exceeding two stories shall have an engineered design in accordance with the Los Angeles Building Code.
91.5.301.1.3.2. Woodframe Structures. (Amended by Ord. No. 186,488, Eff. 12/27/19.) The Building Official shall require construction documents to be approved and stamped by a California licensed architect or engineer for all dwellings of wood frame construction more than two stories in height with basement located in Seismic Design Category A, B, or C. Notwithstanding other provisions of law, the law establishing these provisions is found in Business and Professions Code Sections 5537 and 6737.1.
The Building Official shall require construction documents to be approved and stamped by a California licensed architect or engineer for all dwellings of woodframe construction more than one story in height located in Seismic Design Category D0, D1, D2, or E.
91.5.301.1.5. Seismic Design Provisions for Buildings Constructed on or into Slopes Steeper than One Unit Vertical in Three Units Horizontal (33.3 Percent Slope). (Amended by Ord. No. 186,488, Eff. 12/27/19.) The design and construction of new buildings and additions to existing buildings when constructed on or into slopes steeper than one-unit vertical in three-units horizontal (33.3% slope) shall comply with LAMC Subsection 91.1613.8.
GROUND SNOW LOAD | WIND DESIGN | SEISMIC DESIGN CATEGORY f | SUBJECT TO DAMAGE FROM | WINTER DESIGN TEMP e | ICE BARRIER UNDERLAYMENT REQUIRED h | FLOOD HAZARDS g | AIR FREEZING INDEX i | MEAN ANNUAL TEMP j | |||||
Speed d (mph) | Topographic effects k | Special wind region l | Wind-borne debris zone m | Weathering a | Frost line depth b | Termite c | |||||||
0 | 85 | No | No | No | D2/E | Negligible | 12" | Yes | 39 o to 44 o | No | See Flood Map | 0 | 61.1 o |
For SI: 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.
a. Where weathering requires a higher strength concrete or grade of masonry than necessary to satisfy the structural requirements of this Code, the frost line depth strength required for weathering shall govern. The weathering column shall be filled in with the weathering index (i.e., "negligible", "moderate" or "severe") for concrete as determined from the Weathering Probability Map [CRC Figure R301.2(4)].
b. The frost line depth may require deeper footings than indicated in CRC Figure R403.1(1). The jurisdiction shall fill in the frost line depth column with the minimum depth of footing below finish grade.
c. The jurisdiction shall fill in this part of the table to indicate the need for protection depending on whether there has been a history of local subterranean termite damage.
d. The jurisdiction shall fill in this part of the table with the wind speed from the basic wind speed map [CRC Figure R301.2 (5) A]. Wind exposure category shall be determined on a site-specific basis in accordance with CRC Section R301.2.1.4.
e. Temperatures shall be permitted to reflect local climates or local weather experience as determined by the Building Official.
f. The jurisdiction shall fill in this part of the table with the seismic design category determined from CRC Section R301.2.2.1.
g. The jurisdiction shall fill in this part of the table with (a) the date of the jurisdiction's entry into the National Flood Insurance Program (date of adoption of the first code or ordinance for management of flood hazard areas), (b) the date(s) of the Flood Insurance Study and (c) the panel numbers and dates of all currently effective FIRMs and FBFMs or other flood hazard map adopted by the authority having jurisdiction, as amended.
h. In accordance with CRC Sections R905.1.2, R905.4.3.1, R905.5.3.1, R905.7.3.1, and R905.8.3.1, where there has been a history of local damage from the effects of ice damming, the jurisdiction shall fill in this part of the table with "YES". Otherwise, the jurisdiction shall fill in this part of the table with "NO".
i. The jurisdiction shall fill in this part of the table with the 100-year return period air freezing index (BF-days) from CRC Figure R403.3(2) or from the 100-year (99%) value on the National Climatic Data Center data table "Air Freezing Index - USA Method (Base 32°F)" at www.ncdc.noaa.gov/fpsf.html.
j. The jurisdiction shall fill in this part of the table with the mean annual temperature from the National Climatic Data Center data table "Air Freezing Index - USA Method (Base 32°F)" at www.ncdc.noaa.gov/fpsf.html.
k. In accordance with CRC Section R301.2.1.5, where there is local historical data documenting structural damage to buildings due to topographic wind speed-up effects, the jurisdiction shall fill in this part of the table with "YES". Otherwise, the jurisdiction shall indicate "NO" in this part of the table.
l. In accordance with CRC Figure R301.2(5) A, where there is local historical data documenting unusual wind conditions, the jurisdiction shall fill in this part of the table with "YES" and identify any specific requirements. Otherwise, the jurisdiction shall indicate "NO" in this part of the table.
m. In accordance with CRC Section R301.2.1.2, the jurisdiction shall indicate the wind-borne debris wind zone(s). Otherwise, the jurisdiction shall indicate "NO" in this part of the table.
91.5.301.2.2.6. Irregular Buildings. Prescriptive construction as regulated by this code shall not be used for irregular structures located in Seismic Design Categories C, D0, D1, and D2. Irregular portions of structures shall be designed in accordance with accepted engineering practice to the extent the irregular features affect the performance of the remaining structural system. When the forces associated with the irregularity are resisted by a structural system designed in accordance with accepted engineering practice, design of the remainder of the building shall be permitted using the provisions of this code. A building or portion of a building shall be considered to be irregular when one or more of the following conditions occur:
1. When exterior shear wall lines or braced wall panels are not in one plane vertically from the foundation to the uppermost story in which they are required;
2. When a section of floor or roof is not laterally supported by shear walls or braced wall lines on all edges;
Exception: Portions of floors that do not support shear walls or braced wall panels above, or roofs, shall be permitted to extend no more than 6 feet (1829 mm) beyond a shear wall or braced wall line.
3. When the end of a braced wall panel occurs over an opening in the wall below;
4. When an opening in a floor or roof exceeds the lesser of 12 feet (3658 mm) or 50 percent of the least floor or roof dimension;
5. When portions of a floor level are vertically offset;
6. When shear walls and braced wall lines do not occur in two perpendicular directions;
7. When stories above-grade are partially or completely braced by wood wall framing in accordance with CRC Section R602 or steel wall framing in accordance with CRC Section R603 include masonry or concrete construction; (Amended by Ord. No. 185,587, Eff. 7/16/18.)
Exception: Fireplaces, chimneys and masonry veneer as permitted by this code. When this irregularity applies, the entire story shall be designed in accordance with accepted engineering practice.
91.5.301.2.2.11. Anchorage of Mechanical, Electrical, or Plumbing Components and Equipment. (Renumbered and Amended by Ord. No. 186,488, Eff. 12/27/19.) Mechanical, electrical, or plumbing components and equipment shall be anchored to the structure. Anchorage of the components and equipment shall be designed to resist loads in accordance with the International Building Code and ASCE 7, except where the component is positively attached to the structure and flexible connections are provided between the component and associated ductwork, piping, and conduit.
91.5.311.2. Egress Door. (Amended by Ord. No. 186,488, Eff. 12/27/19.) At least one egress door shall be provided for each dwelling unit. The egress door shall be side-hinged, and shall provide a minimum clear width of 32 inches (813 mm) when measured between the face of the door and the stop, with the door open 90 degrees (1.57 rad). The minimum clear height of the door opening shall not be less than 78 inches (1981 mm) in height measured from the top of the threshold to the bottom of the stop. This is accomplished by providing a door not less than 3 feet in width and 6 feet 8 inches in height. Egress doors shall be readily openable from inside the dwelling without the use of a key or special knowledge or effort. Every interior door shall have a minimum width of 32 inches (813 mm), except for closets less than 10 square feet in size, which shall comply with CBC Section 1010.1.1, Exception 3.
91.5.313.1. Townhouse Automatic Fire Sprinkler Systems. (Added by Ord. No. 186,503, Eff. 3/11/20.) Every newly constructed townhouse must include an automatic residential fire sprinkler system. Where additions or alterations are made to an existing townhouse that does not have an automatic residential fire sprinkler system, and the aggregate value of the additions and alterations within a one-year period equals or exceeds 50% of the replacement cost of the existing building, an automatic residential fire sprinkler system must be installed in the entire townhouse.
91.5.313.2. One and Two-family Dwelling Automatic Fire Sprinkler Systems. (Amended by Ord. No. 186,503, Eff. 3/11/20.) Every newly constructed one or two-family dwelling must include an automatic residential fire sprinkler system. Where additions or alterations are made to an existing one or two-family dwelling, and the aggregate value of the additions and alterations within a one-year period equals or exceeds 50% of the replacement cost of the existing building, an automatic residential fire sprinkler system must be installed in the entire one or two-family dwelling.
An automatic residential fire sprinkler system is not required in an Accessory Dwelling Unit, provided that all of the following are met:
An automatic residential fire sprinkler system is not required in an Accessory Dwelling Unit, provided that all of the following are met:
1. The unit meets the definition of an Accessory Dwelling Unit as defined in the Government Code Section 65852.2.
2. The existing primary residence does not have automatic fire sprinklers.
3. The detached accessory dwelling unit does not exceed 1,200 square feet in size.
4. The unit is on the same lot as the primary residence.
1. Obtain and reasonably use data available from a federal, state or other source; or
2. Determine the design flood elevation in accordance with accepted hydrologic and hydraulic engineering practices used to define special flood hazard areas. Determinations shall be undertaken by a registered civil engineer who shall document that the technical methods used reflect currently accepted engineering practice. Studies, analyses and computations shall be submitted in sufficient detail to allow thorough review and approval.