Insulation pipe specifications include DN, De, d, Φ, etc.; different notations correspond to various pipe materials or applications, indicating different meanings, as follows:
1. DN refers to the nominal diameter of a pipe. Note: This is neither the outer diameter nor the inner diameter. It is the average of the outer and inner diameters, known as the average inner diameter. For example: DN200~Φ219×6; For pipes such as galvanized and cast iron pipes, the pipe diameter should be indicated by the nominal diameter DN; DN—nominal diameter for polyethylene (PVC) pipes, cast iron pipes, steel-plastic composite pipes, and galvanized steel pipes.
2. De refers to the outer diameter of the pipe, typically denoted by De and should be specified in the format of outer diameter X wall thickness. De25 = Φ25 X 3.1 (outer diameter X wall thickness); Tube materials such as seamless steel pipe, welded steel pipe (straight seam or spiral seam), copper pipe, and stainless steel pipe use outer diameter × wall thickness to indicate the tube size; for PPR, PE, and polypropylene pipes, the outer diameter is specified.
3. "D generally refers to the inner diameter; for materials such as reinforced concrete (or concrete) pipes, clay pipes, acid-resistant ceramic pipes, and cylinder tiles, the diameter should be denoted by the inner diameter d; d - the nominal diameter of concrete pipes."
4. Φrepresents the diameter of a circle or tube (commonly referred to as the outer diameter); for plastic tubes, the diameter should be indicated according to the product standard method, usually marked with De; ф—nominal diameter of seamless steel tubes, with specifications like ф100:108*4.
