An Extensive Guide to Companion, Floor, Flat & Raised Flanges for B2B Buyers

Flanges are fundamental components in piping and mechanical systems, widely used across industries such as oil & gas, water treatment, construction, and manufacturing. Although they may appear simple, selecting the correct flange type is critical for system safety, sealing performance, and long-term reliability.

For B2B buyers and engineers, understanding the differences between companion vs. floor flanges and raised face vs. flat face flanges can significantly improve procurement decisions and reduce project risks. This guide provides a clear, practical breakdown to help you choose the right solution.

A flange is a mechanical connection used to join pipes, valves, pumps, or equipment. It allows for:

• Easy assembly and disassembly
• Maintenance and inspection access
• Transition between different materials (e.g., steel to plastic)
• Secure sealing under pressure

Flanges are commonly used in IPS (Iron Pipe Size) systems, especially where frequent dismantling is required.

Companion flanges are designed for pressurized piping systems and are widely used in industrial environments. They follow strict standards (such as ANSI/ASME) and include precise bolt hole patterns for sealing integrity.

Common Types of Companion Flanges

• Threaded Flanges
  Ideal for applications where welding is not feasible. They are easy to install and reusable, making them suitable for maintenance-heavy systems.

• Socket Weld Flanges
  Typically available in sizes up to 6 inches. They provide a strong connection with minimal alignment effort, making installation efficient.

• Weld Neck Flanges
  One of the most reliable options for high-pressure systems. Their tapered hub ensures smooth stress distribution and uninterrupted flow.

• Long Weld Neck Flanges
  Commonly used in pressure vessels and boiler systems. Their extended neck provides reinforcement and improved durability under extreme conditions.

• Blind Flanges
  Used to terminate piping systems. Unlike welded caps, they allow easy reopening for future expansion or inspection.

B2B Insight:

For industrial buyers, companion flanges are the default choice in fluid, gas, and high-pressure systems. Selecting the correct type depends on pressure rating, installation method, and maintenance requirements.

Floor flanges are designed for structural support rather than pressure handling.

Key characteristics:

• No strict bolt hole alignment standards
• Lighter weight compared to pressure flanges
• Not suitable for fluid or gas transfer

Typical Applications

• Fixing pipes or posts to floors, walls, or ceilings
• Furniture and architectural structures
• Decorative or light-duty installations

B2B Insight:

Floor flanges are not interchangeable with companion flanges. Using them in pressurized systems can lead to sealing failure and safety risks.

The flange face determines how sealing is achieved. Choosing the correct face type is essential for leak prevention.

Raised face flanges are the most commonly used type in industrial plants.

Key Features:

• Gasket surface is slightly raised above the bolt circle
• Uses ring-type or partial-face gaskets
• Concentrates pressure on a smaller sealing area

Advantages:

• Better sealing performance under high pressure
• Compatible with a wide range of gasket types
• Ideal for oil, gas, and chemical applications

B2B Insight:

RF flanges are preferred in most steel piping systems due to their superior pressure containment capability.

Flat face flanges have a full-contact gasket surface aligned with the bolt circle.

Key Features:

• Uses full-face gaskets
• Even distribution of bolt load across the entire surface

Typical Applications:

• Cast iron systems
• Low-pressure piping
• Fragile materials where stress concentration must be avoided

Important Rule:

Flat face flanges should not be directly connected to raised face flanges. If necessary, the raised face must be machined flat, and a full-face gasket should be used.

B2B Insight:

Incorrect pairing (RF + FF) is a common procurement mistake that can cause leakage or flange damage.

For procurement managers and engineers, consider the following factors:

• Pressure & Temperature Rating → Choose companion flanges for any pressurized system
• Installation Method → Threaded vs. welded connections
• Material Compatibility → Carbon steel, stainless steel, cast iron, or plastic transitions
• Sealing Requirements → RF for high pressure, FF for low pressure or cast materials
• Future Maintenance → Blind flanges for easy system expansion

In B2B projects, consistency in quality and standards compliance is critical. Working with an experienced manufacturer ensures:

• Compliance with international standards (ANSI, ASME, DIN, etc.)
• Stable supply chain and on-time delivery
• Technical support for application selection

Jizhong provides a wide range of industrial flanges, including companion flanges and customized solutions for global markets. With strong manufacturing capabilities and export experience, Jizhong supports distributors, contractors, and project buyers with reliable and cost-effective products.

Flanges may seem straightforward, but the variety of types and applications can quickly become complex. Understanding the differences between:

• Companion vs. Floor Flanges
• Raised Face vs. Flat Face Flanges

is essential for making the right purchasing decision.

For B2B buyers, selecting the correct flange is not just about price—it directly impacts system safety, sealing performance, and long-term operational efficiency. Partnering with a trusted supplier like Jizhong can further simplify the process and ensure your projects run smoothly.