Why do Europe and the United States have different size standards for grooved fittings?

Table of Content: 
1. Differences in historical and standard-setting backgrounds
2. Impact of differences in measurement units
3. Differences in manufacturing processes and molds
4. Differences in market and application habits

Differences in historical and standard-setting backgrounds

United States:
The United States has its own independent industrial standard system. The pipeline standards in the US were gradually formed during its own industrial development process. The formulation of its size standards took into account numerous factors such as domestic production of pipes, processing techniques, building codes, and practical application scenarios in the US. For example, the commonly used sizes in the US are often derived from conversions based on the inch unit. In the design and application of pipeline systems, there has been a long-term habit of using size specifications that conform to its local industrial production practices.

Europe:
European standards are the result of coordination and unification among European countries. During the industrial development of European countries, each had its own traditional standards. With the progress of European economic integration, organizations like CEN (European Committee for Standardization) have made efforts to coordinate the standards of various countries. European size standards consider factors such as the traditional pipe manufacturing techniques, architectural styles, and engineering requirements in Europe. Under the metric unit-based system, its size specifications place more emphasis on matching and unified application with metric sizes.

Impact of differences in measurement units

United States:
Some pipeline sizes in the US still retain the imperial units. Although there has been a certain degree of coordination with the metric units, after conversion from the imperial units, some specific size values will appear. For example, 1 inch is equal to 25.4 mm, which leads to the appearance of some sizes such as 168 mm (approximately 6.61 inches) in practical applications.

Europe:
Europe mainly uses the metric unit, and its size specifications tend to adopt integer values or sizes that are convenient for calculation and processing in the metric system when designed. For example, the size of 159 mm is more convenient for understanding, production, and use in pipe processing, fitting manufacturing, and engineering installation from the perspective of the metric unit. Whether in mold manufacturing or pipeline connection construction, it conforms to the manufacturing and construction habits in Europe where the metric system dominates.

Differences in manufacturing processes and molds

United States:
The fitting manufacturing enterprises in the US have long been using molds and production processes adapted to the US standard sizes. These processes are optimized around their specific size standards. For some specific-sized fittings, such as fittings with a diameter of about 76 mm (approximately 3 inches), the design of their molds, the parameter settings of pipe processing equipment, etc., are all for producing products that meet the US standards. These processes and molds have gone through long-term development and improvement, and changing the size standards would bring high costs and technical difficulties.

Europe:
The manufacturing processes and molds in Europe are also developed based on their own size standards. For a size like 73 mm, the pipe fitting manufacturing equipment and molds in Europe are designed to precisely produce products that meet the European standards. During the production process, the manufacturing processes in Europe focus on product quality and precision control, and the size specifications of the molds are closely combined with the European standards to ensure that the fittings meet the requirements of European building and industrial pipeline systems in terms of dimensional tolerances and connection performance.

Differences in market and application habits

United States:
The application habits of pipeline fittings in industries such as construction, petrochemicals in the US also influence the use of size standards. For example, in the petrochemical industry, some large pipeline systems have long adopted specific US size standards because the interfaces of supporting equipment, valve sizes, etc., are all designed according to the US standards. In the building water supply and drainage systems, the construction teams and designers in the US are also accustomed to using fitting sizes that meet the US standards, and there is a stable demand for these sizes in the market.

Europe:
The demand for fitting sizes in the European market is affected by its architectural styles and industrial applications. European architecture focuses on space utilization and aesthetics, and the design of water supply and drainage and heating, ventilation, and air conditioning pipeline systems tends to use fitting sizes that meet the European standards. In the industrial field, the pipeline systems in industries such as chemical engineering and pharmaceuticals in Europe are also designed and installed according to the sizes of the European standards, which makes the European market have a continuous demand for fittings that meet the European size standards.