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. The below is a table comparing common properties between HDPE and FRP. Both materials are often used considerations of pressure applications such as piping.

Comparison of FRP with HDPE
Property FRP HDPE
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 ni some installations

Weight Density = 2000 kg/m3 Density = 970 kg/m3

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 strnegth conditions and FRPs higher safety factor of design, FRP is the smart solution for your Plastic needs.

Protector uses exclusively FRP products for every part of our systems. Its high strength and lightweight nature make it the ideal material for construction needs, with complete resistance to chemicals and water immersion – Protectors FRP systems are ideal for your Stormwater treatment systems.

Written by Nathan D. Raco, in partnership with Protector Stormwater management Solutions