St. Gerivatiba, 207 – Butantã, São Paulo – State of São Paulo, Brazil
eTool prepared the Building Life Cycle Assessment of the River One Corporate project, high-rise building whose main objective was to quantify the reduction of environmental impacts to meet the requirements of the LEED Gold certification for the LCA of the whole building.
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 promote sustainable development offering 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);
- Optimize 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
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). eTool 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 understanding the whole building performance.
LCA Software and Inventory
The software used for the study is the eToolLCD from the company eTool. eToolLCD 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 project (Baseline) and the Final project have the same function area in square meters (m²), area and orientation. The results are characterized by square meter for a period of 60 years, considering a total area of 58,331 m².
Lifespan
The 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
- To present for the construction sector that LCA is a viable practice and widely used internationally to promote sustainable development
LCA Results – LEED 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.
| Impact per square meter (m²) (60 years) | Baseline | Final | % reduction |
| Global Warming Potential (kgCO2 eq) | 451 | 413 | 8% |
| Eutrophication (kg PO4 eq) | 0.489 | 0.451 | 8% |
| Acidification of Land and Water Sources (kgSO2 eq) | 2.66 | 2.46 | 7% |
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 of CO2eq | Reduction tonne of CO2eq | % reduction | |
| Baseline (LEED) | 26,308 | – | – |
| Improvements | |||
| 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 | 3.85% | |
| Total reduction | 2,152 | 8% | |
| Final (LEED) | 24,156 |
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 must be executed sooner, since in the conception project as for example, this way is a huge chance of reducing environmental impacts and also making improvements related to materials according to financial viability.
https://www.usgbc.org/projects/river-one-corporate
LCA also include Operation Impacts (Whole Life Cycle)
The LCA of the project realized was includes 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, which in this case bringing it up the biggest impacts.
In addition, we found it necessary to also include in this study, the Whole Life Cycle or Whole Life Carbon to quantify the impacts related to energy consumption, 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).
In this case, the impact of energy is bigger, followed by materials in the second, which consequently increased the impact of the entire project, as shown in the figure below (Impact Summary).
It is important to know which area of impact is most relevant to know where and how to act on improvements in the the project’s design phase and thus have a significant reduction in impact at the lowest possible cost. 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 modeling has been done in a simpler way, without considering the installed systems and equipment. Only the reductions quantified were the energy consumption and water supply and treatment.
| total tonne of CO2eq | Reduction tonne of CO2eq | % of reduction | ||
| Baseline (WLC) | 48,583 | 0 | 0 | |
| Improvements applied in the operational phase | Energy Efficiency | 47,322 | 1,261 | 2.60% |
| Efficient Metals and Crockery | 46,997 | 325 | 0.67% | |
| Automated Irrigation System | 46,956 | 41 | 0.08% | |
| Rainwater Harvesting and HVAC Condenser | 46,947 | 9 | 0.02% | |
| Structure Improvements | Reuse of the existing retaining wall | 46,707 | 240 | 0.49% |
| Prestressed Beams | 46,115 | 592 | 1.22% | |
| Use of cement with 30% slag in concrete | 45,899 | 217 | 0.45% | |
| Concrete transport nearby to the site | 45,800 | 98 | 0.20% | |
| Reinforcement steel recycled content (Rebar) | 45,800 | 0 | 0.00% | |
| Final Project (WLC) | 45,800 | 2,783 | 5.73% |
It is noted there was an increase in the impact when we include the consumption of water and energy in the project and the impact reduction is also small. These results are why all Life Cycle Stages have been seen (A-D). Even the improvement of steel, which had great relevance in the scope of LEED, here in Whole Life Carbon of LCA, when module D (recycling, reuse) is activated, the improvement of the recycled content of steel is not quantified because it comes from a closed chain. Follow the link with the complete explanation.
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.
- Client: CTE, SDI Desenvolvimento Imobiliário and RBR Asset Management
- Location: St. Gerivatiba, 207 Butantã – São Paulo SP – Brazil
- Date: October 2019
This LCA study has been developed by Caio Alencar and certified by Henrique Mendonça from eTool.
