Why is bolting together ASME/ANSI flanges with API flanges not recommended?

Why is bolting together ASME/ANSI flanges with API flanges not recommended?

• A. Weight difference
• B. Material incompatibility
• C. Dimension similarity but different pressure ratings
• D. Size difference

Answer: (C)

Bolting together ASME/ANSI flanges with API flanges is not recommended primarily due to the dimension similarity but different pressure ratings. ASME/ANSI flanges and API flanges, while they may appear similar in dimension, are designed under different standards that dictate their pressure-temperature ratings and structural performance under load. ASME/ANSI flanges are typically used in general piping systems and have standardized pressure ratings tied to their material properties and temperature ratings. In contrast, API flanges are designed specifically for the oil and gas industry, adhering to different criteria, including weight, bolting requirements, and pressure ratings that can differ significantly. When these flanges are combined, a mismatch occurs where the lower-rated flange could fail under pressure loads, which creates a safety hazard. This issue underscores the importance of using flanges that are rated for similar pressures to maintain the integrity of the piping system and ensure safe operations.

Bolting together ASME/ANSI flanges with API flanges is not recommended primarily due to the dimension similarity but different pressure ratings. ASME/ANSI flanges and API flanges, while they may appear similar in dimension, are designed under different standards that dictate their pressure-temperature ratings and structural performance under load.

ASME/ANSI flanges are typically used in general piping systems and have standardized pressure ratings tied to their material properties and temperature ratings. In contrast, API flanges are designed specifically for the oil and gas industry, adhering to different criteria, including weight, bolting requirements, and pressure ratings that can differ significantly.

When these flanges are combined, a mismatch occurs where the lower-rated flange could fail under pressure loads, which creates a safety hazard. This issue underscores the importance of using flanges that are rated for similar pressures to maintain the integrity of the piping system and ensure safe operations.