Service Metal
300# Galvanized Malleable Unions
- SKU:
- XGU
- Availability:
- Usually Ships Same Day
- Weight:
- 0.00 LBS
Description
300# Galvanized Malleable Iron Union
300# Galvanized Malleable Iron Unions are designed to connect two threaded pipes while allowing the piping system to be disconnected for maintenance, service, or equipment removal without rotating the adjoining pipe runs.
Manufactured from durable malleable iron with a hot-dip galvanized finish, these Class 300 unions provide dependable strength, serviceability, and corrosion resistance for plumbing, waterworks, HVAC, mechanical, industrial, compressed air, and outdoor piping applications.
Product Highlights
- Three-piece threaded union design
- Female NPT threaded end connections
- Allows piping to be disconnected without rotating adjoining pipe
- Ideal for maintenance, equipment removal, and future system modifications
- Designed for higher-duty Class 300 threaded piping systems
- Hot-dip galvanized finish for added corrosion resistance
- Durable malleable iron construction
- Malleable castings conform to ASTM A197
- Hot-dipped galvanized fittings conform to ASTM A153
- Malleable unions conform to ASME B16.39
- NPT threads conform to ASME B1.20.1
- Class 300 fittings are UL Listed
- Suitable for water, air, HVAC, mechanical, and outdoor applications
- Approved to ANSI/NSF 61-4 Annex G and CA AB1953 (<0.25% lead)
- Manufactured in an ISO-certified facility
- Country of origin: Thailand & China
Technical Specifications
| Product Type | Threaded Union |
|---|---|
| Material | Malleable Iron |
| Finish | Hot-Dip Galvanized |
| Pressure Class | 300# |
| Connection Type | Female NPT x Female NPT |
| Configuration | Three-Piece Union |
| Primary Function | Serviceable / Removable Threaded Pipe Connection |
| Casting Standard | ASTM A197 |
| Galvanizing Standard | ASTM A153 |
| Union Standard | ASME B16.39 |
| Thread Standard | ASME B1.20.1 |
| Listing | Class 300 Fittings are UL Listed |
| Lead / Potable Water Compliance | ANSI/NSF 61-4 Annex G and CA AB1953 (<0.25% lead) |
| Manufacturing | ISO-Certified Facility |
| Country of Origin | Thailand & China |
Construction & Applications
Malleable Iron Construction
Manufactured from malleable iron castings conforming to ASTM A197 for dependable strength and durability in demanding threaded piping systems.
Three-Piece Union Design
The separable union body allows two threaded piping sections to be connected or disconnected without turning the entire pipe run.
Hot-Dip Galvanized Finish
The galvanized coating conforms to ASTM A153 and provides added protection against rust and corrosion in moisture-prone and outdoor environments.
Why Use a Threaded Union?
Maintenance-Friendly Connection
A union provides a convenient break point in the piping system so pumps, valves, equipment, or pipe sections can be serviced or replaced without cutting the pipe.
Easy Disassembly
Unlike a conventional coupling, the union can be separated at its center connection, allowing adjoining pipe sections to remain threaded in place.
Typical Applications
Mechanical & Commercial Piping
- Mechanical piping systems
- Commercial plumbing
- HVAC piping
- Water distribution
- Compressed air systems
- General utility piping
Service & Equipment Connections
- Pump connections
- Valve assemblies
- Equipment connections
- Maintenance access points
- Future piping modifications
- Outdoor galvanized piping
Ask Willy: Need Pipe Size Help?
Use our common pipe diameters and wall thickness chart to confirm sizing before ordering 300# galvanized malleable iron unions. You can also review the union specification sheet and Certificate of Conformance below.
Standards & Approvals
ASTM Standards
Malleable iron castings conform to ASTM A197, while hot-dipped galvanized fittings conform to ASTM A153.
ASME Standards
Malleable unions conform to ASME B16.39, while NPT threads conform to ASME B1.20.1.
UL & Lead Compliance
Class 300 fittings are UL Listed. Galvanized fittings are listed as meeting ANSI/NSF 61-4 Annex G and CA AB1953 requirements in the supplied product information.
Related Malleable Iron Standards
- Malleable fitting dimensions generally conform to ASME B16.3.
- Malleable bushings, plugs, and locknuts conform to ASME B16.14.
- Malleable unions conform to ASME B16.39.
- NPT threads on applicable fittings conform to ASME B1.20.1.
- Class 300 fittings are UL Listed according to the supplied product information.
Need More 300# Galvanized Malleable Iron Fittings?
Browse our complete selection of 300# galvanized malleable iron fittings, including unions, elbows, tees, couplings, reducing couplings, bushings, and other heavy-duty threaded fittings.
Frequently Asked Questions
What is a 300# galvanized malleable iron union used for?
It is used to connect two threaded pipe sections while providing a removable connection point for maintenance, service, equipment removal, or future system modifications.
What type of connections does this union use?
The union uses female NPT threaded end connections.
How is a union different from a coupling?
A coupling joins two threaded pipes in a conventional fixed connection. A union includes a separable center connection that allows the piping to be disconnected without rotating or cutting the adjoining pipe sections.
Does the entire pipe need to rotate when installing or removing a union?
No. The three-piece union design allows the center connection to be assembled or separated without rotating the adjoining pipe runs.
Where are unions commonly installed?
They are commonly installed near pumps, valves, equipment, appliances, or other components that may require future removal or maintenance.
Why choose galvanized instead of black malleable iron?
The hot-dip galvanized coating provides added protection against rust and corrosion in piping exposed to moisture, humidity, or outdoor conditions.
How is a 300# union different from a 150# union?
The Class 300 fitting is a heavier-duty fitting intended for more demanding threaded piping applications than a standard Class 150 fitting.
What standard applies specifically to malleable iron unions?
Malleable unions conform to ASME B16.39 according to the supplied product information.
What thread standard applies?
NPT threads conform to ASME B1.20.1.
Are Class 300 fittings UL Listed?
Yes. The supplied product information states that Class 300 fittings are UL Listed.
Important Ordering & Installation Notes
- Confirm the required nominal pipe size before ordering.
- This union uses female NPT threaded end connections.
- Verify that a removable union connection is appropriate for the intended piping layout.
- Install the union where future access is available for tightening, inspection, and disassembly.
- Malleable unions conform to ASME B16.39.
- NPT threads conform to ASME B1.20.1.
- Hot-dipped galvanized fittings conform to ASTM A153.
- Use compatible galvanized pipe, fittings, and thread sealant appropriate for the intended system.
- Avoid damaging the galvanized coating during handling and installation.
- Isolate and fully depressurize the piping system before separating an installed union.
- Do not assume the “300#” class designation alone establishes allowable working pressure for every service condition.
- Verify pressure, temperature, media compatibility, potable-water requirements, applicable codes, and approval requirements before installation.
- Refer to the specification sheet and Certificate of Conformance for additional product information.
