Overview
- ISO is the International Organization for Standardization, dedicated to establishing global standards to promote international cooperation and ensure product quality.
- Common terms in piping regulations include S, dn, en, and SDR, which represent pipe series, nominal outside diameter, nominal wall thickness, and standard dimension ratio, respectively.
- S refers to the pipe series, used to classify pipes with similar characteristics.
- dn stands for nominal outside diameter, representing the standard diameter in millimeters.
- en denotes nominal wall thickness, indicating the thickness of the pipe walls, also in millimeters.
- SDR is the standard dimension ratio, the ratio of nominal outside diameter to nominal wall thickness, used to assess the pressure-bearing capacity of pipe materials. The larger the SDR, the lower the pressure capacity, and vice versa.
The International Organization for Standardization (ISO) is dedicated to establishing global standards to facilitate international cooperation and ensure product quality. Common terms in piping regulations include S, dn, en, and SDR, representing pipe series, nominal outside diameter, nominal wall thickness, and standard dimension ratio, respectively.
1. ISO（International Organization for Standardization）
ISO, established in 1947 post-World War II in the United Kingdom with its headquarters in Geneva, Switzerland, is a global independent non-governmental organization comprised of national standards bodies from various countries. It consolidates and combines the opinions of its member countries to establish a common benchmark, promoting good international cooperation. Products certified by ISO, through third-party accreditation, are assured of their quality or service, which in turn enhances the company's quality image.
2. What are S, dn, en, SDR in piping regulations?
( 1 ) S：pipe series
S is a classification based on the relationship between a pipe's "outside diameter dn" and "thickness en." Grouping pipes with similar S values categorizes them with roughly the same pressure resistance. S's purpose is for classifying pipe series. The scope of piping regulations is very broad, with dn12 to dn500 possibly using the same specification, but outer diameters can range from several centimeters to several meters. In a product range that spans more than 100 times, we need a way to categorize them into the same category, including classification by material, size, etc., and S is one of these classification methods.
( 2 ) dn：nominal outside diameter
The standardized standard diameter, in millimeters.
( 3 ) en：nominal wall thickness
The thickness of the pipe wall, in millimeters.
( 4 ) SDR：standard dimension ratio
The standard dimension ratio of pipe material, the ratio of the pipe's nominal outside diameter de to its nominal wall thickness en.
3. The Relationship Between S, dn, en, SDR
In this calculation process, the result obtained is:
Standard Dimension Ratio = Nominal Outside Diameter / Nominal Wall Thickness
Therefore, the larger the SDR, the lower the pressure capacity; the smaller the SDR, the higher the pressure capacity. [1]