Ductile Iron vs
High Density Polyethylene Pipes
The advantages of Ductile Iron pipes are many and have been proven
over many decades and can be summarised as:
- Excellent
corrosion resistance
- The physical
properties of Ductile Iron do not change with age
- Strength of
Ductile Iron is not compromised by time. HDPE’s strength is compromised by time
as it is subject to creep degradation
- Shop coated
Ductile Iron pipe does not require additional corrosion protection in
non-aggressive conditions
- Polyethylene
encasement provides effective corrosion control for Ductile Iron pipe in most
corrosive environments
- Flexible jointing
- Ease of jointing
- Bedding materials
not as critical and more flexible than steel pipes
- No site welding
- Reduced
installation time
- Impact resistance
better than any other pipe material
- Ductile Iron has
up to 12 times more impact strength than HDPE ensuring greater security from
third party interference
- High tensile and
shear strength - Ductile Iron has a
tensile strength > 24 times HDPE
- Low expansion
coefficient - HDPE has a thermal
expansion coefficient > 18 times Ductile Iron
- Cement lining
provides good roughness coefficients
- Radial deflection
is less than HDPE especially at larger diameters
- Crushing load of
Ductile Iron pipe is > 82 times than HDPE pipe
- Axial bending
strength is greater than HDPE
- Ductile Iron
hydrostatic burst pressure up to 6.1 times the burst pressure of HDPE
- Both Ductile Iron
and HDPE pipe would perform well to the chemical composition of raw water
The above advantages lead to a Whole of Life (WOL) cost that is
far superior to HDPE.
