The 1998 California Fire Code, Section
1109.7 requires that all chimneys used for fire places or heating
appliance using solid or liquid fuel shall be equipped and
maintained with an approved spark arrestor.
Approved shall meet the definition of a spark arrester
as defined in the California Building Code, Section 3102.3.8.
Spark Arrester. The net free area of the spark arrester shall
not be less than four times the net free area of the outlet of the
chimney. The spark arrester screen shall have heat and corrosion
resistance equivalent to (0.109 inch (2.77 mm) (No. 12 B.W. gage)
wire, 0.042 inch (1.07 mm) (No. 19 B. W. gage) galvanized wire or
0.022 inch (0.56 mm) (No. 24 B.W. gage) stainless steel.
The spark arrester shall extend above the chimney to a height
of not less than 1.3 times the minimum diameter or horizontal
dimension of the chimney.
Openings shall not permit the passage of spheres having a
diameter larger than 1/2 inch (12.7 mm) and shall not block the
passage of spheres having a diameter of less than 3/8 inch (9.5