Description
Stainless Press Union
Merit Stainless Press Unions are designed to join two compatible stainless steel pipe sections while providing a serviceable connection that can be separated without cutting the piping. The union combines press connections with a removable center joint, making it useful near equipment, valves, and other components that may require future maintenance or replacement.
Merit Stainless Steel Press Fittings are designed for use with Schedule 5 or Schedule 10 Type 304/304L or 316/316L stainless steel pipe conforming to ASTM A-312. The stated working pressure range is from full vacuum to 300 PSI (20.7 bar) on Schedule 5 and Schedule 10 stainless steel pipe.
Product Highlights
- Stainless steel press union
- Serviceable in-line piping connection
- Press connections on both pipe ends
- Removable center union connection
- Allows piping sections to be separated for service
- Designed for Schedule 5 and Schedule 10 stainless steel pipe
- Compatible with Type 304/304L stainless steel pipe
- Compatible with Type 316/316L stainless steel pipe
- Designed for ASTM A-312 stainless steel pipe
- Working pressure range from full vacuum to 300 PSI
- Maximum stated working pressure: 300 PSI / 20.7 bar
- Manufacturer approvals, dimensional information, tooling guidance, and compatibility documentation available below
Technical Specifications
| Product Type | Press Union |
|---|---|
| Material | Stainless Steel |
| Connection Type | Press |
| Configuration | In-Line Union |
| Serviceability | Removable Center Union Connection |
| Compatible Pipe Material | 304/304L or 316/316L Stainless Steel |
| Compatible Pipe Schedule | Schedule 5 or Schedule 10 |
| Pipe Standard | ASTM A-312 |
| Working Pressure Range | Full Vacuum to 300 PSI |
| Maximum Working Pressure | 300 PSI / 20.7 bar |
| Primary Function | Joining Two Stainless Steel Pipe Sections With a Serviceable Connection |
Press Union Design
A stainless press union combines press-connected pipe ends with a center union joint that allows the piping connection to be separated when service is required.
This configuration can simplify maintenance because connected equipment or piping sections can be removed without cutting the pipe or disturbing a larger portion of the system.
Press unions are especially useful near valves, pumps, filters, regulators, equipment, and other components that may require periodic access or replacement.
Why Choose a Press Union?
Serviceable Connection
- Allows two piping sections to be separated
- Useful for equipment maintenance and replacement
- Provides a planned disassembly point
- Can reduce the need to cut installed piping
- Suitable for serviceable mechanical assemblies
Mechanical Press Installation
- Press connections at the pipe ends
- Uses compatible press tooling
- No pipe threading required at the press connections
- No fitting weld required at the press connections
- Designed for compatible stainless steel piping systems
Press Union vs. Press Coupling
Press Union
- Designed for future disassembly
- Includes a removable center union connection
- Useful near serviceable equipment
- Allows connected sections to be separated without cutting pipe
- This product configuration
Press Coupling
- Provides a direct in-line press connection
- Used primarily to join two pipe sections
- Does not provide the same removable center joint
- Common for permanent straight-run connections
- Different serviceability from a union
Compatible Stainless Steel Pipe
304 / 304L Stainless Steel
- Compatible pipe material identified by Merit
- Schedule 5 or Schedule 10 pipe
- Pipe must conform to ASTM A-312
- Verify pipe dimensions and condition before installation
- Confirm chemical compatibility for the intended media
316 / 316L Stainless Steel
- Compatible pipe material identified by Merit
- Schedule 5 or Schedule 10 pipe
- Pipe must conform to ASTM A-312
- Suitable where the specified system requires 316/316L pipe
- Confirm chemical compatibility for the intended media
Pressure Range
Merit states that its Stainless Steel Press Fittings have a working pressure range from full vacuum to 300 PSI (20.7 bar) when used on compatible Schedule 5 or Schedule 10 stainless steel pipe.
System suitability should be confirmed based on fitting size, pipe material, temperature, conveyed media, chemical compatibility, installation method, and the applicable Merit Stainless Press documentation.
Common Applications
Commercial & Mechanical Piping
- Valve connections
- Pump connections
- Equipment connections
- Filter and regulator assemblies
- Mechanical piping systems
Industrial & Process Service
- Process piping systems
- Serviceable equipment connections
- Maintenance access points
- Compatible utility piping
- Applications requiring future disassembly
Installation & Selection Guidance
- Confirm the required nominal union size before ordering.
- Use only compatible Schedule 5 or Schedule 10 stainless steel pipe.
- Confirm pipe is Type 304/304L or 316/316L stainless steel as required.
- Verify that the stainless steel pipe conforms to ASTM A-312.
- Inspect and properly prepare both pipe ends before installation.
- Insert each pipe to the required depth before pressing.
- Use compatible press tooling approved for the Merit Stainless Press system.
- Follow the applicable pressing sequence and tooling instructions.
- Position the union so the center connection remains accessible for future maintenance.
- Properly align the connected piping before tightening the union joint.
- Avoid using the union to pull misaligned piping into position.
- Support connected piping as required to prevent excessive load on the fitting.
- Confirm system media compatibility using the Merit chemical compatibility chart.
- Verify that the full-vacuum-to-300-PSI working range is suitable for the intended system.
- Review applicable approvals and submittal requirements before installation.
Product Documents
Merit Stainless Press Approvals
Review applicable approvals and certifications for the Merit Stainless Press fitting system.
Merit Stainless Press Benefits & Features
Review manufacturer information covering key benefits and features of the Stainless Press system.
Merit Stainless Press Dimensional Catalog
Review fitting dimensions, available sizes, and product-specific dimensional information.
Merit Stainless Press Chemical Compatibility Chart
Review chemical compatibility information before selecting fittings for the intended system media.
Merit Stainless Press FAQs
Review manufacturer answers to frequently asked questions about the Merit Stainless Press system.
Merit Stainless Press Handout
Review the manufacturer overview of the Stainless Press product line and system features.
Merit Stainless Press Linecard
Review the available Merit Stainless Press product offering.
Merit Stainless Press Submittals
Review technical submittal information for the Merit Stainless Press fitting system.
Merit Stainless Press Tooling
Review compatible tooling information and pressing requirements before installation.
Pipe Chart: Common Diameters & Wall Thicknesses
Reference common pipe diameters and wall thicknesses when reviewing Schedule 5 and Schedule 10 stainless steel pipe.
Need Help Selecting a Stainless Press Union?
Our industrial PVF specialists can help review your union size, stainless steel grade, pipe schedule, serviceability requirements, working pressure, media compatibility, and tooling requirements before you order.
Frequently Asked Questions
What is a stainless press union used for?
It is used to join two compatible stainless steel pipe sections while providing a connection point that can be separated later for maintenance or equipment removal.
How is a press union different from a press coupling?
A press union includes a removable center connection for future disassembly. A press coupling provides a more permanent straight-through connection between two pipe sections.
Can the piping be separated after installation?
Yes. The union connection is intended to provide a serviceable point where the joined sections can be separated without cutting the press-connected pipe ends.
Where are press unions commonly used?
They are commonly useful near valves, pumps, filters, regulators, and other equipment that may need periodic service or replacement.
What pipe is this fitting designed for?
Merit identifies the Stainless Press system for Schedule 5 or Schedule 10 Type 304/304L or 316/316L stainless steel pipe conforming to ASTM A-312.
What is the working pressure range?
The stated working pressure range is from full vacuum to 300 PSI (20.7 bar) on compatible Schedule 5 and Schedule 10 stainless steel pipe.
Does this fitting require welding?
No fitting weld is required at the press connections. The pipe ends are connected using compatible press tooling.
Can this fitting be used with both 304 and 316 stainless steel pipe?
The supplied Merit information identifies Type 304/304L and 316/316L stainless steel pipe conforming to ASTM A-312.
What pipe schedules are compatible?
The supplied Merit information identifies Schedule 5 and Schedule 10 stainless steel pipe.
Where can I verify available union sizes?
Use the Merit Stainless Press Dimensional Catalog in the Product Documents section above.
Where can I check chemical compatibility?
Use the Merit Stainless Press Chemical Compatibility Chart in the Product Documents section above.
Where can I find compatible press tooling?
Use the Merit Stainless Press Tooling document in the Product Documents section above.
Important Ordering Notes
- Product is a stainless steel press union.
- Provides a serviceable in-line connection between two pipe sections.
- Press connections are used at the pipe ends.
- Center union connection allows future disassembly.
- Designed for Schedule 5 or Schedule 10 stainless steel pipe.
- Compatible pipe materials identified as 304/304L and 316/316L stainless steel.
- Compatible pipe must conform to ASTM A-312.
- Working pressure range is stated as full vacuum to 300 PSI / 20.7 bar.
- Confirm nominal union size before ordering.
- Position the union so the center connection remains accessible for future service.
- Confirm media compatibility using the manufacturer chemical compatibility chart.
- Use compatible Merit Stainless Press tooling.
- Review approvals, dimensional information, tooling requirements, and submittals before installation.
