ASME B16.47 is an American Society of Mechanical Engineers (ASME) standard that specifies the dimensions, materials, and tolerances for large diameter steel pipe flanges. The standard covers flanges with nominal pipe sizes (NPS) from 26 to 60 and pressure class ratings from 75 to 900. ASME B16.47 flanges are divided into two series: Series A and Series B. Series A flanges are based on the MSS SP-44 standard, while Series B flanges are based on the API 605 standard. The main difference between the two series is that Series A flanges have a larger bolt circle diameter than Series B flanges. ASME B16.47 flanges are typically used in high-pressure and high-temperature applications, such as in the oil and gas industry. They are also used in other industries, such as the chemical, power, and water treatment industries. Here are some of the key features of ASME B16.47 flanges: They are made of steel, cast iron, or stainless steel. They have a raised or flat face. They have a bolt circle diameter that ranges from 125 to 600 millimetres. They have a pressure class rating that ranges from 75 to 900. They have a thickness that ranges from 6.3 to 127 millimetres. ASME B16.47 flanges are an important part of many piping systems. They help to ensure the safe and reliable operation of these systems.