At One Place

HDPE

Density of HDPE
955 kg/m³ (940–970)
0.95 g/cm³ · 59.6 lb/ft³

The blue and yellow pipe under every modern street: it is welded rather than jointed, so a run has no leak paths, and it flexes with ground movement instead of cracking like the cast iron it replaced. It also floats, is unaffected by almost every household chemical, and is self-lubricating enough to be used as low-load bearing material. Like polypropylene it will not take glue or paint; the only reliable joining method is heat welding.

Properties

Density
955 kg/m³ (940–970) — 0.95 g/cm³
Melting range
125–135 °C
Tensile strength
20–37 MPa
Young's modulus
1 GPa
Thermal conductivity
0.45 W/(m·K)
Thermal expansion
120 µm/(m·K)
Floats in water
Yes
Magnetic
No

What it is used for

  • Milk bottles and detergent containers
  • Water and gas mains pipe
  • Chopping boards and playground furniture
  • Chemical storage tanks

How it compares

Water is 1,000 kg/m³. Anything with a shorter bar than water floats in it.

air 1.2 kg/m³
expanded polystyrene foam 20 kg/m³
rigid polyurethane foam 40 kg/m³
HDPE 955 kg/m³
Water — the float line 1,000 kg/m³
tungsten 19,250 kg/m³
gold 19,300 kg/m³
platinum 21,450 kg/m³
Water is 1,000 kg/m³. Anything below that floats.
Material Density Relative to water
rigid polyurethane foam 40 kg/m³ 0.04×
expanded polystyrene foam 20 kg/m³ 0.02×
air 1.2 kg/m³ 0.00×
HDPE ← 955 kg/m³ 0.95×
platinum 21,450 kg/m³ 21.45×
gold 19,300 kg/m³ 19.30×
tungsten 19,250 kg/m³ 19.25×

Does it rust?

HDPE contains no iron, so it cannot rust. Whether it degrades depends on the material, not on oxidation.

Is it magnetic?

HDPE is not a metal and has no ferromagnetic response.

Common questions

What is the density of HDPE?
955 kg/m³ (940–970), or 0.95 g/cm³.
Does HDPE float?
Yes. At 955 kg/m³ it is less dense than water's 1,000.
Is HDPE magnetic?
HDPE is not a metal and has no ferromagnetic response.

Related pages

Sources

  1. Typical range compiled from manufacturer specifications — At One Place

How these figures are compiled and checked