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Ballast Water Systems
Large-diameter isolation, compact installation and frequent ballast or deballast operating cycles.
Typical positions: Ballast mains · Tank branches · Pump discharge
RECOMMENDED PRODUCTS
Marine Valves for Shipboard Water Systems
Union Valve supplies butterfly valves, gate valves and check valves for primary isolation and non-return duties in seawater cooling, ballast water, bilge, freshwater, HVAC, fire-water and shipboard water-treatment systems.
✓ Valve options for main-line isolation, equipment isolation and pump-discharge protection
✓ Selection based on medium, DN, pressure, temperature, corrosion exposure, connection type and actuation
✓ Materials, seats, coatings and approval requirements reviewed against the specified marine service
MARINE APPLICATIONS
Marine Valve Solutions by Shipboard Water System
Select an application to review its main valve duties, typical line positions and suitable Union Valve product categories.
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Bilge Water Systems
Isolation and reverse-flow prevention where oil, solids and cleaning chemicals may affect valve sealing.
Typical positions: Bilge wells · Pump suction · Pump discharge
RECOMMENDED PRODUCTS
03
Seawater Cooling Systems
Isolation and backflow prevention under chloride exposure, corrosion, deposits and marine growth.
Typical positions: Sea chests · Cooling mains · Heat-exchanger branches
RECOMMENDED PRODUCTS
04
Freshwater & HVAC Systems
Equipment isolation and pump protection for chilled, cooling, domestic-water and HVAC circuits.
Typical positions: Pumps · Chillers · Supply and return mains
RECOMMENDED PRODUCTS
05
Fire-Water Systems
Dependable isolation and non-return protection subject to project standards, monitoring and approvals.
Typical positions: Fire pumps · Pump discharge · Fire mains
RECOMMENDED PRODUCTS
06
Shipboard Water Treatment
Process and equipment isolation around filtration, disinfection and ballast-water treatment skids.
Typical positions: Skid connections · Pump discharge · Auxiliary lines
RECOMMENDED PRODUCTS
Selection note: Confirm medium, DN, pressure, temperature, materials, seals and project approvals before ordering. Products marked * require service-specific review. Fuel-oil and lubricating-oil systems are not included in this initial scope.
Recommended Valves for Shipboard Water Systems
Product selection should be based on the shipboard system, medium, line size, design pressure, temperature, chloride exposure, installation space, connection standard, actuation and applicable project approvals.
Butterfly Valves
Compact isolation for ballast, cooling, freshwater and HVAC lines. Wafer and lug types fit restricted spaces; double-flanged types suit selected larger mains.
Use: Main-line and equipment isolation
Options: Wafer · Lug · Double flanged
Confirm: DN · Pressure · Materials · Seat · Actuation
Gate Valves
Full-bore isolation for selected ballast, bilge, freshwater and fire-water pipelines where unrestricted flow is required.
Use: Fully open or fully closed isolation
Options: Resilient seated · NRS · OS&Y
Confirm: Medium · Pressure · Connection · Stem design
Check Valves
Automatic backflow prevention on pump discharge and other non-return lines. Select the closing response for actual flow and surge conditions.
Use: Pump protection and backflow prevention
Options: Swing · Dual plate · Silent check
Confirm: Velocity · Orientation · Solids · Surge risk
Flanged Ball Valves
Quick on/off isolation for selected equipment branches, drains, sampling points and treatment auxiliary lines—not primary large-diameter mains.
Use: Branch and equipment isolation
Options: Flanged connection
Confirm: DN · Medium · Pressure · Temperature · Seat
MARINE VALVE SELECTION
How to Choose Marine Valves
Start with the shipboard system and actual medium, then confirm the valve duty, operating conditions, materials, installation requirements and applicable project standards.
System & Medium
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Valve Duty
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Operating Conditions
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Materials
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Installation
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Standards
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01 START HERE
Define the System and Medium
Identify where the valve will operate and what will pass through it. Application names alone do not define the final valve configuration.
- Seawater, freshwater or treated water
- Bilge water, suspended solids or oil contamination
- Treatment chemicals and chloride exposure
- Continuous or intermittent service
Why it matters The medium affects body, trim, seat and coating selection. -
02 FUNCTION
Match the Valve to Its Duty
Select the product category according to the required function in the pipeline, rather than using one valve type throughout the system.
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03 SERVICE DATA
Confirm Operating Conditions
Valve size and pressure rating are only part of the selection. Flow behavior and operating frequency can also change the suitable design.
- DN and required pressure rating
- Operating and design temperature
- Flow velocity and allowable pressure drop
- Operating frequency and water-hammer risk
For check valves Confirm orientation, flow velocity and closing behavior. -
04 MATERIALS
Select Materials for the Service
Marine material selection should review the complete valve configuration instead of specifying only a corrosion-resistant body.
- Body and coating system
- Disc or closure component
- Stem, shaft and fasteners
- Seat and sealing compatibility
For seawater Review chloride level, temperature, exposure time and galvanic compatibility. -
05 INSTALLATION
Check the Installation Conditions
Available space, connection details and access for operation or maintenance can determine the practical valve design.
- Wafer, lug, flanged or grooved connection
- Face-to-face and flange requirements
- Manual, electric or pneumatic operation
- Access for inspection and maintenance
Installation check Confirm actuator clearance, orientation and removal space. -
06 COMPLIANCE
Verify Standards and Approvals
Marine, fire-water and potable-water projects may specify standards, testing, documentation or model-level approval requirements.
- Applicable design and connection standards
- Inspection and pressure-testing requirements
- Material certificates and project documents
- Required marine or service approvals
Before ordering Verify the exact valve model and configuration required.
PROJECT-BASED SELECTION
Need Help Choosing Marine Valves?
Send us the system, medium, DN, pressure, temperature, connection standard and required approvals.
Application scope: Final selection must be reviewed against the specified marine service. Fuel-oil and lubricating-oil duties require separate confirmation of the valve design, sealing materials, temperature range and relevant project records.
Marine Valves FAQs
Which butterfly valve is suitable for ballast water systems?
Resilient-seated wafer, lug or double-flanged butterfly valves are commonly used, depending on pipe size, pressure and maintenance needs.
What is the difference between wafer, lug and flanged marine butterfly valves?
Wafer valves are compact; lug valves allow easier pipeline maintenance; double-flanged valves provide stronger support for larger sizes.
Which seat materials are suitable for seawater and freshwater?
EPDM is commonly used for water service. NBR, FKM or PTFE may be selected according to temperature, chemicals and operating conditions.
How should valve materials be selected for seawater?
Select materials according to chloride level, temperature, pressure and corrosion risk. Body, disc, stem and seat materials must be evaluated separately.