How Are The Pressure Ratings Stipulated in The Design Standards of Gate Valves?

BS 5150 (Cast Iron Gate Valves): It stipulates the pressure-temperature ratings of cast iron gate valves under different operating conditions. These ratings are determined based on the properties of cast iron materials and the structural design of the valves. For example, under normal temperature conditions, it will specify a maximum allowable working pressure to ensure that the valves can operate safely in general industrial or civil applications such as plumbing systems.

BS 5153 (Copper Alloy Gate Valves): For copper alloy gate valves, considering the characteristics of copper alloy materials, the corresponding range of pressure-temperature ratings is determined. Since the mechanical properties of copper alloys are different from those of materials like cast iron, the pressures they can withstand at different temperatures also vary. The standard lists these parameters in detail to make the valves meet the safety and performance requirements in appropriate application scenarios such as plumbing systems.

BS 5163 (Steel Gate Valves): The stipulations on the pressure-temperature ratings for steel gate valves are more detailed. Taking into account multiple factors such as the strength of steel, it divides into several pressure rating ranges and gives the corresponding allowable working pressure ranges under each rating in combination with temperature changes. This helps to accurately select suitable steel gate valves according to the specific pressure and temperature environments in industrial and civil pipeline systems.

API 600 (Steel Gate Valves for the Petroleum and Natural Gas Industries): In the high-pressure and complex working conditions of the petroleum and natural gas industries, the stipulations on pressure ratings are very strict. It details the pressure ratings that the valves can withstand at different temperatures. These ratings are based on the properties of steel materials and the overall structural design of the valves. For example, in the high-temperature and high-pressure wellhead devices of oil wells, the valves must be able to withstand specific pressures, and the API 600 standard ensures that the gate valves can meet the pressure requirements under these extreme conditions.

API 6D (Pipeline Valves including Gate Valves): For gate valves used in long-distance pipelines, the stipulations on pressure ratings need to consider the working pressure of the pipelines and the characteristics of the medium. It specifies the pressure ratings of the valves under different pipeline pressure environments and has strict requirements for the stability and reliability of the valves under pressure. Because the medium in long-distance pipelines is usually in a high-pressure state, the valves need to ensure the safe operation of the pipelines.

ASME B16.34: This standard provides extensive pressure-temperature ratings for various valves including gate valves. It determines the pressure ratings based on factors such as the mechanical properties (such as strength, toughness, etc.) of materials and the dimensions of the valves. For gate valves of different nominal pressure ratings, such as Class 150, Class 300, etc., it clearly specifies the corresponding maximum allowable working pressures within different temperature intervals, providing a basic pressure parameter basis for the design of valves under various working conditions such as high temperature, high pressure, and corrosive media.

ISO 15761 (Industrial Valves including Gate Valves): Focusing on functionality and safety in design, it also has corresponding stipulations on pressure ratings. It specifies the methods for determining the pressure ratings of gate valves under different working environments (including different temperatures and media). By considering factors such as the structural strength and material properties of the valves, it ensures that the valves can operate safely and effectively within the specified pressure ranges, aiming to achieve consistency in valve design and quality control on a global scale.

ISO 7005-1 (Metal Flange-related Standard but Affecting the Connection Parts of Gate Valves): Although it is mainly a standard for metal flanges, since the flange connection parts of gate valves are closely related to pressure tightness, its stipulations on the pressure ratings of flanges also indirectly affect gate valves. It specifies the applicable ranges of different types of flanges (such as flat welding flanges, butt welding flanges, etc.) under different pressure environments, thereby ensuring that gate valves can withstand the corresponding pipeline pressures after being connected by flanges.

MSS SP-70 (Steel Gate Valves with Flanges and Butt Welding Ends): While stipulating the manufacturing quality and dimension tolerances of components such as the valve body and valve cover of the valves, it also involves content related to pressure ratings. Based on the properties of steel materials and the structural characteristics of the valves, it stipulates the pressure rating ranges of gate valves under different working conditions to ensure the safe use of flange and butt welding end steel gate valves in pipeline systems.

MSS SP-71 (Gray Cast Iron Gate Valves): For gray cast iron gate valves, considering the material characteristics of gray cast iron, the corresponding pressure ratings are stipulated. It will specify the parameter requirements under normal working pressure and, considering possible pressure fluctuations, ensure that parameters such as the minimum wall thickness of gray cast iron gate valves can meet the pressure requirements and avoid damage such as cracking during the use process.