Oyster - Automatic Flood Barriers (Custom Quote)
Garrison Flood Protection • Custom Quote
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Automatic flood protection for garages, driveways, loading docks, transit entrances and other downward-sloping access points.
The Garrison Oyster™ Self-Rising Mechanical Flood Gate is a hydrodynamic, water-activated flood barrier designed to protect downward-sloping entrances, including parking garage ramps, driveway ramps, transit and subway station openings, loading docks, tunnels and other below-grade access points.
Under normal conditions, the Oyster™ flood gate remains flat on the ramp, allowing vehicles and pedestrians to pass freely. When floodwater approaches, water enters the barrier's internal cavities and creates buoyancy that automatically raises the panel into a vertical flood wall. No electricity, motors or manual deployment are required. Once flood conditions subside, the system can be returned to its closed position.
The Oyster™ flood gate uses a passive hydrodynamic mechanism within each module to detect rising water and automatically raise the flood panel, creating a protective barrier against incoming floodwater.
Vehicles and pedestrians can pass normally over the anti-skid driving surface. The flood panels remain flush with the concrete or sit directly on top of the existing surface.
As floodwater approaches, it flows through the inlets into internal water-storage cavities within each module.
Buoyancy acts on internal flotation plates, which then push the rotating flood panel upwards.
When the water reaches the design activation threshold, the flood gate modules rise into position and lock into a near-vertical flood wall.
Continuous ramp seals and flexible side-wall seals create a tight seal to help prevent water from entering the protected opening.
The Oyster™ system is fully passive and does not require human intervention to deploy.
Integrated drainage and water outlet controls allow small amounts of water to drain away, helping prevent unnecessary deployment caused by shallow ponding. The barrier rises only when incoming flow exceeds the drainage capacity.
Once the flooding event has ended, water drains from the internal cavities. Operators can then follow the required procedure to lower the panel back to its flat position and visually check the seals and hardware before the next use.
The hydrodynamic system rises using the ballast of incoming floodwater. No electricity, pumps, motors or staff deployment are required.
The four-layer, heavy-duty panel structure is designed to support vehicle loads. Cars and light trucks can pass over the closed barrier and, where required and within design limits, safely drive out over the ramp even when the barrier is raised.
The panels can be installed in-ground or positioned on top of concrete, with a ramped thickness of approximately 2.0–3.9 inches.
Standard flood gate modules are approximately 23.6 inches wide, while non-standard filler units are available in 6.3, 11.4, 13.2 and 18.5-inch widths. This modular approach allows the system to match a wide range of ramps and openings.
Adjustable side seals and optional Z-profile gap fillers accommodate variations in wall alignment. Depending on the protection height, the distance between the barrier and wall can generally range from approximately 2.0–5.9 inches.
A recessed embedded frame can be selected for new construction, while a surface-mounted frame is suitable for retrofit projects where cutting into the slab is not practical. Both installation methods use the same core barrier modules.
The system uses aluminium, aluminium castings, 316L stainless steel and nodular cast iron, together with EPDM or silicone rubber sealing components.
The Oyster™ passing flood gate system has been used at hundreds of installations globally and is designed for repeated flood protection.
Durable
Built using durable materials, hardware and construction for long-term use.
Automatically Rises
The passive flood gate rises automatically using hydrostatic pressure, without electricity or battery power.
3 Heights
Available in 24, 36 and 48-inch heights, depending on the required flood protection level.
The Oyster™ self-rising flood gate system is built from standard modules combined with non-standard filler modules and flexible side seals at each wall. Two installation methods are available:
Deployment operating principle: The system uses passive hydrodynamic buoyancy and requires no external power. Panels automatically flip upwards without electricity or manual intervention.
Optional control & alarms: A local battery-powered alarm box or control panel can be used to signal deployment status and provide audible or visual alerts.
For closer fitting around different opening dimensions, Oyster™ uses narrower filler modules. These can be combined with standard modules to accommodate variations in opening width and provide a closer fit to side walls.
Example: For a 9-foot opening, four 23.75-inch standard units plus one 6.3-inch filler create a 101.3-inch section (8 feet 5.3 inches). The remaining 4.7 inches can be accommodated using flexible rubber side-wall seals on either side of the opening.
Flexible rubber sealing plates span the remaining distance between the flood gate panels and the side walls. As the flood barrier rises, these seals flex upwards to maintain a secure seal along both sides of the opening.
Typical design ranges – distance from wall to main frame:
Triangular side seals are fixed to the wall using stainless steel strips and anchors and are sized specifically for each required protection height.
For surface-mounted installations, standard powder-coated steel ramps or wider, more pedestrian-friendly ramp options can be selected. Wider ramps are suitable for non-vehicular access areas such as transit systems, malls and lobby entrances.
In-ground Oyster™ systems use powder-coated steel filler sections in place of ramp components.
Each standard Oyster™ flood gate panel is a four-layer composite engineered for strength, buoyancy and skid resistance.
Panel Construction
Aluminium tread top layer with anti-slip texture for vehicle and pedestrian safety.
Heavy-duty cast-aluminium structure designed to handle vehicular traffic and rated for garage and ramp applications.
316L stainless steel structure with electrophoretic coating and spray finish, creating sealed cavities for buoyant elements that lift the panel.
304 stainless steel protects the buoyancy system from impact and corrosion.
Base frame and structural plates are manufactured from aluminium and aluminium castings.
Other Key Elements
Shipping quoted separately: Shipping for Garrison Flood products is customized based on the product and delivery location and is not included in the listed price. Purchase your product now to receive a separate shipping quote afterward, or contact Home Power Tech before ordering at support@homepowertech.com or call/text 727-334-0176. We’ll confirm the shipping cost with you before arranging shipment.
Shipping is additional unless listed. Call/text 727-334-0176 or email us for a quote. Shipping quoted after purchase requires approval before dispatch.
In-stock standard items: 4–7 days. Includes handling/transit. Listing or quote exceptions take priority.
Yes: Clamshell, YellowFIN, MAKO, and Hammerhead. MAKO also has standard sizes. Send measurements, photos, quantities, and ZIP code. Approve specifications before fabrication.
Check dimensions, protection height, sealing surfaces, quantities, and required equipment. Follow model instructions; no barrier guarantees protection against every flood.
Only if expressly included. Confirm shipping method, access, unloading, site preparation, and installation in your quote.
Standard items: 30-day returns, unused and complete in original packaging; 10% change-of-mind fee and free authorized return shipping. Custom items: no change-of-mind returns unless your quote allows them. Report defects or damage to us. See our Refund & Returns Policy.
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