"Letter to Editor" addressing the carbon footprint of Plastic Pipes

Dear Editor,

Your December issue of Drain Trader carried an article on the Hereford Flood alleviation scheme in which Asset International referred to the “carbon footprint” of its Weholite High Density Polyethylene pipe product.  We believe this information to be highly misleading.

The “carbon footprint” is described as 252 “kg of Carbon” per meter of pipe.  This value cannot be true unless the DN2000 Weholite pipe is under 100kg in weight per meter.

We estimate that the Weholite DN2000 HDPE pipe transported from South Wales to Hereford should have a cradle-to-site carbon footprint of 622 or 756kg CO2e kg per metre for pipes with stiffness class 2kN/m2 and 4kN/m2 and weight 160kg/m and 195kg/m respectively, according to Asset international’s product literature.  This is considerably higher than the 592kg C02e for a DN 2100 concrete pipe.

Our calculations for plastic pipes takes into account: (i) the methane generated during production of the HDPE resin, which can increase the C02-only figure by around 25%, (ii) the manufacturing and transport emissions from the resin’s original source; (iii) transport of the finished product to site.

The carbon footprint of the pipe is only part of the story; to understand the impact of the project, the type and nature of the bedding material required should also be considered.  Without this, any comparison between pipes would fail the basic requirements of comparative environmental assessments in accordance with ISO 14044.

We would be more than happy to share the detailed calculations we have carried out to to reach these conclusions, and urge Asset International to make their own information, methodology and calculations public which, after all, is a basic requirement of the recognised carbon footprint methodologies.

Without a full explanation of the calculation method, we have to conclude that the manufacturer has, disappointingly, failed to understand the principles of carbon footprinting and Life Cycle Assessment.

For the record, the CPSA has recently published an independent Pipeline Systems Comparison Report looking at the embodied cradle-to-site- carbon emissions of different pipeline materials.  This report can be found at http://www.concretepipes.co.uk/documents/PipelineComparisonReport-Final-13-06-11.pdf

Yours sincerely,

Stuarts Crisp
Business Development Director
Concrete Pipeline Systems Association