Investigations About Power Consumption and Carbon Footprint Used by Different Pipe Lining Methods

In the 21st century, climate protection is becoming more and more important, and there is a special focus on finite resources and environmental needs. This includes the construction industry, where many companies are trying to “GO GREEN”.

One of the biggest issues for the environment is the climate change caused by the greenhouse effect. A lot of factors affect climate change, also known as the “Global Warming Effect“ (GWE), which are summarized under the expression of the CO2 equivalence, or “Carbon Footprint”. This explains how a fixed mass of a greenhouse gas will affect the greenhouse potential, such as CO2, methane, N2O, etc.. With that knowledge, it is possible for products and services to create a special and unique “Product Carbon Footprint“ or PCF. There are strong discussions on political and economic levels to point out PCFs for various products and services, including those associated with the construction industry.

Regarding this issue, a Bachelor thesis was presented by Tom Küter, of the University of Applied Sciences, Technology, Business and Design (Wismar, Germany) in 2013 and supported by Professor Jens Hölterhoff, Dr. Jürgen Alexander, and Michael Röhling.

The title of the thesis is “Expansion of an Existing Calculation Sheet Determining the CO2-Emission from Cured-in-Place Pipe (CIPP) Installations, Taking Manufacturing Processes into Account“. The thesis included:

Setting up of an Excel® spreadsheet for determining CO2 emissions for manufacturing of Glass-fiber Reinforced Plastics (GRP) and Felt liners, including the transportation from production site to the job site
Implementation of the calculation program for CO2 emissions including a Manual of Practice.
The thesis analyzed and developed a kind of “Energy Calculator“ to allow the user to input individual job site parameters and conditions for determination CO2 equivalents. In addition, the user can consider different CIPP solutions within this trenchless industry, such as hotwater -, steam -, and UV curing methods with different liner materials like felt or fiberglass.

The user is able to deliver the input data in Metric or Customary units. Job site criteria and specific lining materials, wall thickness, installation lengths, and bypass pumping will affect the CO2 output. The different CIPP curing methods, with their characteristic temperature profile and pressure during curing, are taken into account to get an accurate CO2 output of the end product in the ground.

That means the duration of the highest sustained temperature and temperature on the outside of the liner , and air flow and the capacities of heating machine and generator on the other side, are considered using different products.

The Energy Calculator includes the emissions of all the manufacturing processes of CIPP materials, including inserted fiberglass and synthetic felt (a polyethylenterephthalate) as raw material, polyester resin production, inner foil/coatings, and the transportation to/from the factories themselves. All of these specific values of CO2 equivalents could be analyzed by GaBi 6 Software from PE International, source CML 2001-Nov.2010 determined by engineering and consultancy office Dr. Wessling.

With knowledge of the amount of fiberglass and resin consumption per square meter (m2) of pipe surface, an exact emission of CO2 in kilograms (kg) is possible for all processes: manufacturing, transportation and installation. Results are available or each wall thickness of liner, presented in kg of CO2 per m2 per meter of pipe liner.


As stated above the goals of the thesis included development of an Excel® spreadsheet for easily inputting parameters for typical construction sites. The carbon footprint should indicate how much emissions will affect the environment by using different CIPP methods. The Energy Calculator compares the CO2 equivalents in kg/meter depending on the different liner types and curing methods.

Manufacturing of the basic raw materials, transportation, and installation are considered in single and complete sums, which results in the total CO2 emission for a characteristic footprint of a specific job site.

The comparison and analysis of each CIPP method shows the following:

The biggest and most influential factor is the manufacturing of the lining materials.
The UV installation process using fiberglass liners produces the lowest CO2 emission, followed by the steam curing method.
Hot water curing produces the highest amount of CO2 emissions.
Generally there is a tendency of low carbon footprint compared to the conventional CIPP methods in front of the most beneficial relation between the resin and the wall thickness with fiberglass liners.
The reinforcement with fiberglass induce especially in big diameters from static design reasons to explicit smaller wall thickness and therefore come along with lowest CO2 equivalents.

The positive effect of the inserted process energy during the installation as less time for the process itself, smart technology and less equipment show up additional positive effects to a better environmental balance.

An additional economical analysis is not a part of the Energy Calculator, but should be considered by the user based on total job site conditions in each case study.

Author: Dr. Jürgen Alexander, Global Business Development Director at iMPREG Group