GH-39 StaInless Steel & Aluminum Flap Gates

Model GH-39SS Stainless Steel Flap Gate


This Section Covers Stainless Steel Flap Gates. The equipment provided under this section shall be fabricated, assembled, erected, and placed in proper operating condition in full conformity with the drawings, specifications, engineering data, instructions and recommendations of the equipment manufacturer. Gates shall be supplied with all the necessary parts and accessories indicated on the drawings, specified, or otherwise required for a complete, properly operating installation, and shall be the latest standard product of a manufacturer regularly engaged in the production of fabricated water control gates.


Gates supplied under this section shall be Model GH-39SS Stainless Steel Flap Gates as manufactured by Golden Harvest Inc. or pre-approved equal.


The manufacturer shall have 10 years experience in the production of hydraulic control gates and have a licensed engineering staff with a minimum of 10 years of experience in the design of hydraulic control gates. The manufacturer’s shop welds, welding procedures and welders shall be qualified and certified in accordance with the requirement of the latest edition of AWS Sections D1.1, 1.2 & 1.6.

The fully assembled gates shall be shop inspected, tested for operation and adjusted before shipping. There shall be no assembling or adjusting on the job site.


The manufacturer shall submit for approval by the purchaser, drawings showing the principal dimensions, general construction and materials used.


Flap gates shall be substantially watertight under the design head conditions. Under the design seating head, the leakage shall not exceed 0.10 US gallons per minute per foot of seating perimeter.

When specified, flap gates shall open with low differential head and be supplied with dual hinge (pivot) arms. The flap gate shall begin to open with x.x-ft (x.x-meters) differential unseating head pressure. Please consult with Golden Harvest, Inc when specifying ‘low differential head’ flap gates.


General Design. Flap gates shall be stainless steel designed to mount direct to a concrete wall, wall thimble or spigot style mounted around a pipe. Gates shall be designed and constructed to withstand the maximum seating head as shown in the gate schedule. The flap gate shall pivot from a single hinge point to allow free flow on the unseating head side.


Part Material
Frame, Flap, Hinge Arms, Pins Stainless Steel Type 304L, 316L ASTM A-240 & 276
Seals Neoprene ASTM D-2000
Seal Retainer UHMW-PE ASTM D4020 or Stainless Steel T-304 / 316 ASTM 276
Hinge Bushing Self-Lubricating Fiberglass Reinforced DIN ISO 4379
Fasteners & Hardware Stainless Steel Type 304, 316 ASTM F593 / F594
Anchor Bolts Stainless Steel Type 304, 316 ASTM A276


The gate spigot and flange shall be constructed of stainless steel members to form a one-piece rigid frame.

The spigot shall be design in such a way to place the flap at an approximate 2.5° degree taper to allow for positive closure.


The gate cover shall consist of stainless steel plate reinforced to limit its deflection to L/360 of the gates span under the design head condition.


Flap gates shall be hinged at the top with a minimum two [2] hinge arms construction stainless steel plate or shapes.

Flap gates required to open with low differential head pressure shall be supplied dual hinge/pivot system. The upper hinge shall provide opening sensitivity adjustment.


Hinge pin and fasteners shall be machined of stainless steel round bar. Hinge bushings shall be self-lubricating fiberglass, Gar-Max or approved equal.

RESILIENT SEAL: Seals shall be of resilient neoprene and be attached to body with a UHMW-PE or stainless steel retainer strip.

MOUNTING GASKET: When required, flap gate shall be mounted with a minimum of 3/8 in. (10mm) thick neoprene gasket and sealant. Sealant shall be Bostic 915 industrial sealant or approved equal.



Contractor shall exercise the following precautions with Flap Gates.

Handling: Avoid bending, scraping or overstressing the gates.

Transportation: Loading, transporting and unloading of the gates shall be conducted such that the gates are kept clean and free from damage.

Protection: Provide sheltered onsite storage. Provide blocking, platforms, or skids to protect the gates from contact with the ground. Protect the gates from damage from construction activities or equipment.