minimum design & construction standards - Martin County, Florida

tested and witnessed by a Department’s representative prior to the actual tap
of the main. The pipe coupon shall be carefully preserved and submitted to the
Authority’s representative. All tapping sleeves shall be installed a minimum of
18 inches from pipe joints.
K) All field cuts on pipe shall require careful repair of the particular lining damaged
in strict accordance with the manufacturer’s recommendations.
L) Fire hydrants shall be installed true and plumb. Hydrant extensions shall not
be permitted in new construction.
19. Horizontal Directional Drilling
The following standards pertain to the design and construction of horizontal directional
drilling of water mains in the Martin County Utilities service area.
A) Pipe sizes and material: Horizontal directional drilled utility pipe shall be
HDPE pipe (SDR 11 minimum). If the directional drilled pipe is to be used as
a casing for a small diameter service line (up to 2” diameter), DR 18 pipe is
acceptable. Pipe and couplings shall be free from voids, cracks, inclusions,
and other defects and shall be uniform in color throughout the installation.
B) Design Requirements: The Engineer shall inquire with the Department about
approval of a horizontal directional drilling procedure for a pipe installation.
With the Department’s concurrence, the Engineer shall submit a signed and
sealed pilot bore plan for review and approval. The plan shall be submitted
on a 24” x 36” sheet to a maximum 1” = 20’ horizontal and 1” = 2’ vertical
scale (1” = 10’ horizontal, 1” = 1’ vertical scale preferred). The plan must
show:
• Finished grade and surface improvements
• Locations of drill set-up
• Length of bore
• Deflection and radii of the pilot bore
• Locations of existing utilities and underground structures
• Minimum horizontal and vertical clearances from underground structures,
conduits, piping systems (the proposed clearances must exceed the
Departments standards plus the guidance system accuracy tolerance)
• Pipe size and specifications
• Proposed pilot bore pipe deflection limits (not to exceed 75% of the
maximum deflection allowed by the pipe manufacturer)
• Limits of directional bore installation
• Limits of pressure testing
• Connection to existing utilities
• Rights-of-way limits, utility easements and temporary construction
easements
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