Blogs

HDPE, or high density polyethylene is a petroleum based thermoplastic with a high strength to weight ratio. It is often comparable to FRP as they are both plastic based materials with altered properties. Both materials are often used considerations of pressure applications such as piping.

The main differences between FRP and HDPE are listed below:

Property	FRP	HDPE
Type	FRP is Orthotropic composite material	HDPE is isotropic material.
Pricing	Installation cost, maintenance, and cost over life of the system considered less.	Lower initial Cost
Thermal expansion and contraction	Lower thermal expansion, with 1/10thof the expansion and contraction of HDPE	Higher expansion per degree than FRP
Operating and Design temperatures	FRPs mechanical properties do not degrade until roughly 83-104.5	HDPE tends to lose its mechanical properties drastically at 22 degrees. Becomes not recommended when the temperature exceeds 80 degrees.
Strength	Ultimate Stress = 110MPa	Ultimate Stress = 23MPa
Pressure Design	Designs at minimum a 6:1 ratio in pressure situations	Lower safety factor in designs causing extreme occasions to be big issue for HDPE
Fabrication and Installation	Can be manufactured more simply and on site, whereas HDPE requires fabrication in manufacturing plants in complex processes	Can be manufactured to smaller diameters with HDE being quicker to produce
Modulus of Elasticity	Hoop Modulus = 27.58GPa Axial Modulus = 12.4GPa	HDPE Modulus = 0.69GPa HDPE has higher in ground deflection and pipe bending. Requires piping supports in some installations
Weight	Density = 2000 kg/m3	Density = 970 kg/m3
Note	Much lighter in weight due to lower all thickness even though the density of FRP is normally higher than HDPE	Heavier due to higher wall thickness.

Overall FRP is a much more suitable material for construction purposes. HDPE has a much lower strength than FRP so is a much less suitable material for high strength applications such as underground installations. With the shorter lifespan of HDPE under high strength conditions and FRPs higher safety factor of design, FRP is the smart solution for your Plastic needs.