What is the American standard for flanges?

The main standards for American flanges are ANSI (American National Standards Institute) B16.5 and ANSI B16.47. These standards set specifications for the size, material and connection of flanges.

ANSI B16.5 is the commonly used flange standard for 1/2 inch to 24 inch calibers. The standard includes various flange types, such as blind flange, butt welded flange, threaded flange, seam welded flange, etc. It covers the size of the flange, the spacing and size of the bolt holes, the form and requirements of the sealing surface, etc.

ANSI B16.47 is a standard for larger diameter flanges and is applicable to flanges 26 inches and above. The standard is divided into Series A and Series B two series, the main difference is the bolt hole spacing and sealing surface form. Series A is suitable for welded neck flanges while Series B is suitable for blind flanges and removable flanges.

These standards are widely used in the engineering, construction and manufacturing industries in the United States to ensure the uniformity and interchangeability of flanges. However, it is necessary to select the appropriate standard and type of flange according to the specific engineering requirements and design specifications.