Combining Flanges: Same Rating and Size Considerations

When dealing with flanges in industrial and commercial settings, it's important to understand the specifications and standards that govern their use. A common question that arises is whether two flanges of the same rating and size, but with different numbers of holes, can be used together. Specifically, Could I use a four hole flange and an eight hole flange together if they are the same rating and size?

Dimensions and Bolting Concerns

The response to this query is a clear no. The dimensions and bolting patterns for flanges are meticulously designed to work in tandem with the specific rating and size. Even if you could somehow make the dimensions line up, attempting to combine a four-hole flange and an eight-hole flange would result in a union that is likely to leak.

ANSI B16.5 Standards

In the United States, ANSI (American National Standards Institute) B16.5 sets the standards for dimensions, bolting, and working pressure/temperatures for pipe flanges. These standards are crucial for ensuring safety and functionality in pressurized systems.

My machine shop specializes in making flanges. If you have any further questions or need assistance with flange-related queries, feel free to contact me. I hope this helps clarify the situation.

Limited Scenarios for Non-Industrial Uses

For certain non-industrial uses, such as hanging garden ornaments, combining flanges might be feasible. However, in pressurized systems and commercial applications where pressure codes and standards apply, the answer is definitively no. These standards dictate that the flange ratings (which include the thickness, number of bolt holes, size of bolts, and PCD (pitch circle diameter) of bolts, as well as the internal and external diameters of the flange) must all be consistent for the union to be structurally sound and safe.

Flange Rating Importance

Flange ratings are critical in determining the flange's ability to withstand specific pressures and temperatures. They specify key parameters such as:

Flange thickness Number of bolt holes Size of bolts PCD (Pitch Circle Diameter) of bolts ID (Inside Diameter) and OD (Outside Diameter) of the flange

Any attempt to force two flanges together, especially those of different ratings, would either not work or result in an inferior union. This is particularly problematic in pressurized systems, where even the slightest leakage can lead to unsafe conditions.

Conclusion and Further Inquiry

If you have a specific application in mind, such as hanging a garden ornament where structural integrity isn't a primary concern, you might be able to combine flanges. However, for pressurized systems, where pressure codes and standards apply, ensuring that the flange ratings are consistent is paramount. If you need further guidance or have any specific questions about your project, feel free to reach out. The safety and functionality of your system depend on adhering to these standards.