Every swimming pool shall be equipped with a pressure sand filter
or an approved equal. Filters will be approved if certified tests
from an independent testing laboratory are submitted to the building
inspector indicating that the filter tested is equal to the pressure
sand filter in the following:
(2) Dirt-holding
capacity and length of filter cycle;
(1974 Code of Ordinances, Chapter 28 1/2, Sec. 28
1/2-26)
(a) The filter
system shall have sufficient capacity to provide a complete turnover
of the pool water in eight (8) hours or less, when operated at a rate
not to exceed three (3) gallons per minute per square foot of filter
area.
(b) The recirculating
pump shall have sufficient capacity to backwash the filter at a rate
of at least ten (10) gallons per minute per square foot of filter
area, when operating against the total head of the backwash system.
The pump motor shall not be operated at overload which exceeds the
service factor.
(1974 Code of Ordinances, Chapter 28 1/2, Sec. 28
1/2-27)
Pool pumps shall be equipped on the inlet side with an approved
type hair and lint strainer. The basket of the strainer shall be non-corrosive
and shall have an open screen surface of at least ten (10) times the
cross-sectional area of the inlet pipe.
(1974 Code of Ordinances, Chapter 28 1/2, Sec. 28
1/2-28)
(a) Size
of Sand.
Filter sand shall be a hard, uniformly graded
silica material with effective particle sizes between 0.45 and 0.55
millimeters in diameter with uniformity coefficient of 1.45 to 1.69.
There shall be no limestone or clay present.
(b) Depth
of Sand.
Filter sand shall be no less than nineteen (19)
inches in depth with a freeboard of no less than nine (9) inches or
no more than twelve (12) inches.
(c) Grades
of Rocks.
There shall be no less than four (4) grades
of rock which shall be clean, noncrushed, rounded noncalcareous material.
(d) Depth
of Rock Bed.
The total depth of the rock-supporting bed
shall be no less than fifteen (15) inches and each grade shall be
two (2) inches or greater in depth. Each layer of rock shall be leveled
to prevent intermixing of adjacent grades.
(e) Size
of Layers.
The top layer shall vary in size between one-eighth
(1/8) inch and one-fourth (1/4) inch. The next layer shall vary in
size between one-fourth (1/4) inch and one-half (1/2) inch. The next
layer shall vary in size between one-half (1/2) inch and three-quarter
(3/4) inch. The bottom layer shall vary in size between one (1) inch
and one and one-half (11/2 ) inches.
(1974 Code of Ordinances, Chapter 28 1/2, Sec. 28
1/2-29)
Filter tanks shall be built for a minimum of fifty (50) pounds
working pressure with a safety factor of four (4). The filter under
drain shall have an effective distribution of at least twenty-five
(25) percent of the cross-sectional area of the tank. Tanks placed
underground shall be steel plate at least three-sixteenths (3/16)
inch in thickness, with an approved noncorrosive exterior coating.
Filter tanks shall be supported in a manner to prevent tipping or
settling.
(1974 Code of Ordinances, Chapter 28 1/2, Sec. 28
1/2-30)
Operating instructions shall be posted on every filter system
and all valves shall be properly designated with metal tags indicating
purposes or methods of use.
(1974 Code of Ordinances, Chapter 28 1/2, Sec. 28
1/2-31)
The filter system shall be equipped with the following:
(1) A pressure
gauge on the influent piping;
(2) A pressure
gauge on the effluent piping;
(3) A method
of releasing the air at the top of the filter;
(4) A backwash
sight glass if the backwash discharge outlet to the receptor is not
visible from the backwash control valve. (Sight glass shall be installed
adjacent to the backwash control valve.)
(1974 Code of Ordinances, Chapter 28 1/2, Sec. 28
1/2-32)
Pool piping shall be sized to permit the rated flows for filtering
and backwashing without exceeding the maximum head at which the pump
will provide such flows. In general, the water velocity in the pool
piping should not exceed ten (10) feet per second. The recirculating
piping and fittings shall meet the following requirements:
(1) The vacuum
inlet fittings shall be located in an accessible positions below the
water line.
(2) An outlet
shall be placed at the deepest point in every pool for recirculation
and emptying the pool.
(1974 Code of Ordinances, Chapter 28 1/2, Sec. 28
1/2-33)
Fullway valves shall be installed to insure proper functioning
of the filtration and piping system as follows:
(1) A valve
shall be installed on the main suction line located in an accessible
place outside the wall of the pool.
(2) Valves
up to, and including two (2) inches in size, shall be brass. Sizes
over two (2) inches may have cast-iron or brass bodies. All working
parts of valves shall be of noncorrosive material.
(3) Combination
valves may be installed if the materials and design comply with the
intent of this article.
(1974 Code of Ordinances, Chapter 28 1/2, Sec. 28
1/2-34)