A stack of black polyethylene pressure water pipes with thin blue co-extruded stripes, seen from the pipe ends in an outdoor pipe yard in soft morning light

ASTM D3350 Cell Classification: How to Read PE445574C, and Why the Fifth Digit Is the PENT Test

The PPI Municipal Advisory Board’s model specification for PE4710 water pipe, revised in June 2026, asks for a compound meeting ASTM D3350 minimum cell classification PE445574C-CC3. That string answers what the standard is for. ASTM D3350 identifies a polyethylene pipe or fittings compound by six cell numbers and a letter: density, melt index, flexural modulus,

ASTM D3350 Cell Classification: How to Read PE445574C, and Why the Fifth Digit Is the PENT Test Lire plus "