RIVER ONE – LEED

Project Details

• Developer: CTE, SDI Desenvolvimento Imobiliário and RBR Asset Management
• Location: St. Gerivatiba, 207 Butantã – São Paulo SP – Brazil
• Date: October 2019
• Lifespan: 60 years
• LCA authored by Caio Alencar of Cerclos and the critical review has been conducted by Henrique Mendonça of Cerclos.

Cerclos prepared the Building Life Cycle Assessment of the River One Corporate project, a high-rise building whose main objective was to quantify the reduction of environmental impacts to meet the requirements of the LEED certification – Building Life Cycle Impact Reduction credit. 

The LCA model used for the LEED credit was expanded to include operational energy and operational water. Although the operational impacts are not required for the LEED credit, this integrated analysis gave the project team a whole life carbon performance and an understanding of relevance of main improvement strategies as described below in this case study.  

Life Cycle Analysis of Buildings (LCA) is a method for evaluating the environmental impacts associated with the life cycle phases of a project. It is a holistic approach that encompasses raw material extraction, material manufacturing and transportation, energy and water use, maintenance, reuse, recycling, and end-of-life disposal of materials. The LCA study allows identifying potential areas for reducing the environmental impact and may also include improvement recommendations for the project team. Building LCA is regulated by the international standards ISO 14044 and EN15978 and the application in the construction sector is used worldwide to the main benefits:

• Ensuring that lifetime impacts are considered from the design phase and provide information for project development;
• Ensure that the analysis includes the entire building throughout its useful life (cradle-to-cradle);
• Optimise performance during all stages of the project’s life, provided that improving a specific area does not detract from the performance of the project as a whole.
• Consider multiple impact indicators and prevent the transfer of impact from one project area to another;
• Ensure that the analysis is done following the international standards compliance of the LCA methodology so that the studies are comparable and accessible for interpretation.

LCA Scope for LEED Certification

The LEED credit for Building LCA is focused on products and materials and does not consider the impacts and benefits associated with the operational phase (B6 energy and B7 water) or the loads and benefits beyond the system boundary (module D). Cerclos recommends the LCA for future projects be carried out also to fully meet the requirements of the European standard EN15978 including all life cycle modules (A1-A5, B1-B7, C1-C4 and D1-D5) to understand the whole building performance. 

LCA Software and Inventory 

The software used for the study is eTool from the company Cerclos. eTool complies with ISO 14044 and EN 15978 and produces results for the required impact indicators. The software database (inventory) used was the North American V13 Life Cycle Strategies/EcoInvent which complies with the ISO14044 standard. The characterization method of impact indicators is CML IA Baseline V4.5 (Institute of Environmental Science).

Equivalent Function

The Reference Design (Baseline) and the Final Design have the same function area in square metres (m²), area and orientation. The results are characterised by square metres for a period of 60 years, considering a total area of 58,331 m².

Lifespan

LCA considers a useful life of 60 years and allows impacts related to maintenance, replacement and operational use to be adequately considered. 

Main objectives of LCA

• Quantify the main improvement strategies implemented in the project and identify the contribution of each one in increasing the environmental performance of the project as a whole; 
• Create baseline data for LCA of buildings in Brazil;
• Create a case study to promote the use of the methodology in Brazil and LEED certification;
• Present to the construction industry that LCA is a viable practice and widely used internationally to promote sustainable development.

LCA Results – Building Life Cycle Impact Reduction credit scope

The LCA credit for LEED has a reduced scope, it only covers the Life Cycle Modules (A1-A4, B1-B5, C1-C4) of the elements referring to the foundation, structure, envelope and roofing (Core and Structure). Although the certification is only looking at the commercial area, the LCA study includes the building as a whole, including the residential area, because it’s in the same structure. 

In addition, the result of the study needs to demonstrate a reduction in the three indicator’s impacts, one of them must be the GWP (Global Warming Potential), the responsible impact for climate change.

See Appendix 1.1

The main improvements results of the embodied impact in the reduce of materials for LEED certification were:

• Reuse of the existing retaining wall;
• Prestressed beams;
• Use of cement with 30% slag in concrete;
• Concrete transport nearby to the site;
• Reinforcement steel recycled content (Rebar)

Relevance of each implemented improvements:

	Total Tonne CO2eq	Reduction Tonne CO2eq	% Reduction
Baseline Design (LEED)	26,380	–	–
Improvement Strategies
Reuse of the existing retaining wall		255.18	0.97%
Prestressed instead of solid beams		618.23	2.35%
Use of cement with 30% slag in concrete		178.89	0.68%
Concrete transport nearby to the site		86.82	0.33%
Reinforcement steel recycled content		1,012.85	3.84%
Total Reduction		2,152	8%
Final Design (LEED)	24,228	–	–

This study was important to quantify the impact reduction of the improvements implemented by the project team and also as a reference for future projects, since the LCA was carried out with the work in progress. It is worth mentioning for future projects that LCA should be conducted during the concept stage to increase the potential for impact savings while identifying the most cost effective strategies.

LCA including Operation Impacts – Whole Life Carbon

The original LCA of the project included the embodied impacts of the foundation, structure, envelope, and roof materials following the LEED scope related to the construction phase, maintenance, and end of life. In addition, the design team found it necessary to consider the whole project performance and quantify the impacts related to energy consumption, water supply and water treatment as guided by the LCA standard EN 159781, with all stages of the Life Cycle (A1-A5, B1-B7, C1-C4 and D1-D5).

Below are the quantified improvements for the Whole Life Carbon project including the reduction of emissions (CO2eq) and the percentage of reduction in relation to the total impact measured. This modelling has been simplified without considering the installed systems and equipment. Only the reductions quantified were the energy consumption and water supply and treatment.

See Appendix 1.2

It is noted there was an increase of the overall impacts when the consumption of water and energy were included, therefore reducing the final percentage savings. The improvement of steel recycled content had great relevance in the scope of LEED because of the reduced impact at the product stage. But in the Whole Life Carbon model, when module D (recycling, reuse) is included, the improvement of the recycled content of steel is neutral because it comes from a closed-loop chain. More details in this link. 

The purpose of this suggestion to use rebar with higher recycled content is to encourage manufacturers to reduce initial impacts at the product stage (A1-A3). This “benefit” is reported for the LEED scope only. LEED does not consider module D, which is the reuse of

steel at the end of its life. Following the technical standard (EN15978), as steel is a closed-loop recycling material, the fact that it has a high recycled content does not interfere with the end result of the life cycle. In addition, it is worth mentioning that the energy and water consumption of the building refers to the commercial building, whose area is 22,138 m2.

The integrated design approach gives the project team an overview of the whole project performance and also the comparison and relevance of improvement strategies covering different areas of the project including materials, structural optimisation, energy and water use efficiency.