Current through Register Vol. 24-18, September 15, 2024
(1)
Grease interceptor
compartments. Grease interceptor tanks must be designed and constructed
with a minimum of two compartments. This standard may be met by one tank with
two compartments or by two single compartment tanks in series.
(a) The capacity of the first compartment
must accommodate at least one half but no more than two thirds the total
required liquid volume; and
(b) The
capacity of the second compartment must accommodate the remaining total
required liquid volume.
(2)
Grease interceptor inlets.
Grease interceptors must have inlets that meet the following:
(a) The sanitary tee or baffle must extend
into the liquid a distance within eighteen inches from the bottom of the
tank;
(b) The sanitary tee or
baffle must extend above the liquid surface at least to the crown of the inlet
pipe; and
(c) The invert of the
inlet pipe must be a minimum of two inches above the invert of the tank
outlet.
(3)
Grease
interceptor outlets. Grease interceptors must have outlets that provide
for adequate grease storage and the outlet sanitary tee or baffle must extend:
(a) Into the liquid to a point between six
inches and twelve inches from the bottom of the tank; and
(b) Above the liquid level sufficiently to
allow scum storage and venting, and to a point not less than one inch from the
underside of the top of the tank. The outlet tee may extend into the riser for
venting.
(4)
Grease interceptor intercompartmental wall fittings.
(a) All grease interceptor intercompartmental
wall fittings must extend into the liquid to a point between six inches and
twelve inches from the bottom of the tank.
(b) If slots or ports are used as
intercompartmental fittings:
(i) The location
of the slot or port must be at the same depth as the bottom of outlet tees or
baffles; and
(ii) The opening must
have a minimum area of twelve square inches with a minimum vertical dimension
of three inches.
(5)
Grease interceptor
intercompartmental walls. Grease interceptor intercompartmental walls
must:
(a) Restrict solids from moving from
one compartment to the other except through the intercompartmental wall
fittings; and
(b) Withstand pumping
of the adjacent compartment without risking structural damage or functional
failure.
(6)
Grease interceptor tank liquid depth. Grease interceptor tanks
must contain a liquid depth of not less than three feet.
Statutory Authority: RCW 43.20.050(2) and (3). 09-23-119,
§ 246-272C-0230, filed 11/18/09, effective
12/19/09.
