minimum design & construction standards - Martin County, Florida

AWWA C-500, latest revision. Valves shall be designed for a working pressure of not less
than 200 psi. Each valve shall have the pressure rating cast into the body and
manufacturer's name or initial cast into body or bonnet.
Valving of all systems shall be designed to facilitate the isolation of each section of pipeline
between intersections of the grid system. Generally, the number of valves at an
intersection shall be one less than the number of pipes forming the intersection.
Valves shall generally be installed at intervals of not more than 1,500 LF on transmission
mains and on all primary branches connected to these lines. In high density areas, valves
shall be installed at closer intervals as necessary to minimize the number of persons
affected by a break.
In all instances, effectiveness of placement shall be primary criteria in determining valve
locations. Valves shall not be placed in swales or ditches.
All valves, bends, tees, crosses and dead ends shall be restrained.
Clearance of 18 inches shall be maintained between all fittings (bells, valves, flanges, etc.).
Dead ends that may be extended in future shall have a gate valve with a mechanical joint
plug at the termination point. The valve shall be restrained a minimum of two full joints
back.
All pressure pipe fittings of size 4” and larger shall be ductile iron fittings, with mechanical
joints, unless plans call specifically for flanged, restrained joint fittings. Mechanical joint
fittings shall be used for buried installations; flanged fittings shall be used for above ground
installations. Mechanical joint fittings shall conform to ANSI/AWWA C-153/A21.53.
All valve boxes on 4” valves or larger, shall be 2-piece cast iron construction
with screw type riser sections. The valve box lid shall carry the word “SEWER” and be the
deep skirt type. Valve boxes must have a minimum inside diameter of 5-1/4”. A square
concrete collar that is 24”x24”x6” thick shall be poured at the top of each valve box at
finished grade.
Height adjustments to valve boxes will require a screw type, cast iron extension. A Tyler
series 6850 (2 piece c.i.) valve box or equal will be used. No. 58 and No. 59 high
extensions will be used, if necessary. No substitutions with PVC will be allowed.
When the gate valve is deeper than 36” an extension will be required to bring the operating
nut within 24” of finished grade. A ¼”x3” 316 stainless steel roll pin will be inserted through
the valve-operating nut to secure the extension stem.
6. Minimum Cover
Minimum Cover to finished grade over force main shall be 48 inches.
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