Material Efficiency for Green Building in Indonesia

Sustainable Building Materials

Reusing materials as building materials is an effort to create environmentally friendly architecture, particularly in Indonesia. Furthermore, the understanding of green materials is not limited to building materials that are environmentally friendly but also related to aspects of the origin of the material, the production process, transportation, and installation in buildings. Thus, we will delve more into the opportunity and challenges of the reuse of building materials in Indonesia based on the following consideration:

A. Embodied energy in materials

B. Material selection

C. Green building certification.

A. Embodied Energy in Materials

In general, embodied energy represents the energy used in creating the building materials’ extraction, production, transportation to a factory or the construction site, and the manufacturing process. It also includes the ‘recurrent’ embodied energy used in the maintenance and refurbishing processes of building materials and components and the demolition energy necessary for the deconstruction of building and disposal of waste materials, which produce carbon emissions. Furthermore, the manufacturing process accounts for the largest proportion of the embodied energy and emissions associated with the life cycle of a building product.

• Limitations and Challenges in Indonesia

In this day and age, architects and engineers still have no access to any information concerning the manufacturing process in the technical datasheets of materials, which prevents them from having the chance for a sensible choice of reusing building materials.

• Opportunities and Strategies in Indonesia

In most cases, paying attention at the early design stage and making sensible design and specification choices can reduce embodied energy significantly. Innovative approaches to reusing materials could be made possible by selecting alternatives to the basic structural elements. Architects can influence the embodied energy of materials by using the site as the source of materials by:

• Reducing the energy wasted in hauling them offsite

• Reducing the need to bring in new materials.

Furthermore, they can re-use the existing building components, especially the smaller components (i. e. bricks/ doors/ whole structural slab Of the building. Another option could include:

• Compressed earth block (CEB) from extracted soil

• Stone

• Recycled Concrete for aggregates

• Sand

• Timber

• Agricultural products such as bamboo or straw bales.

Concrete blocks are the greenest among stainless steel cladding and clay bricks, as they have low embodied energy and high potential to use recycled aggregates and cement substitutes. Stainless steel cladding requires a lower quantity of material, and steel is manufactured with 95% recycled content. Clay bricks, however, are typically kiln-fired and have high embodied energy and associated emissions.

Regarding alternative materials, slabs for floors and roofs typically use concrete. These elements are the largest contribution to emissions from building materials, especially in multi-story/high-rise buildings.

Regarding embodied energy saving, the alternatives for a typical floor slab compared to a typical in-situ Reinforced Concrete Slab are as follows: precast unit, waffle slab, trough slab, and filler slab. Furthermore, adding Ground-granulated Blast-furnace Slag saves 7%, using Polystyrene Filler Slab Saves 21%, using Hollow Concrete Panels Saves 29%, and using a thinner Slab-such as Concrete Poured on top of a corrugated sheet saves 39 %. 

 B. Material Selection

The choice of material is closely related to the passive design of green buildings. Therefore, architects can control the core elements that consist of passive design features, material specification, and a building's shape & form, which is an essential consideration because it determines the surface area that can save the embodied energy in the building materials.

•  Limitation and Challenges in Indonesia

Materials must comply with a wide range of requirements established by national laws, national/international standards, codes of practice, and local building habits, which makes the materials’ selection multi-criteria and quite challenging, at least in terms of:

1. Mechanical properties (for structural materials), such as strength, stiffness, and behavior in case of seismic activities that run rampant in Indonesia

2. Thermal performance to achieve an acceptable energetic behavior during the operating phase of the building.

3. Durability in the specific environmental context where the building will be located.

4. Weight and dimension limits in compliance with the specific features of the building.

5. Safety during the materials handling and placing, as well as in case of fire

6. The aesthetic outcome, also in accordance to the local construction traditions in Indonesia

7. Cost, according to the available budget.

• Opportunities and Strategies in Indonesia

First of all, an architect can influence by selecting and reusing materials with low environmental impact by considering the following factors:

1. Dependency on the city where the project is located in Indonesia

2. The available local materials

3. The size and scale of the building. 

 C. Green Building Certification

Suppose we see in the assessment parameters that exist in Indonesia such as Greenship 1.2 from Green Building Council Indonesia (GBCI) and Rating Tools from Ministry of Public Works and Housing (PUPR). In that case, material components are also an assessment in green building certification. The fourth category in the Greenship 1.2 green building assessment is Material Resources and Cycle (MRC).

Moreover, applying such tools requires consideration in terms of time and cost. It is usually carried out mainly for new buildings, even if some tools, such as EcoEffect, were developed for existing and high-quality buildings. These assessment tools are mainly suitable for the early stage of building design and, hence, for supporting the first ‘strategic’ choices. Their applicability to selecting commercial materials to be re-used is scarce.

• Limitation and Challenges in Indonesia

While there is a common agreement in considering the impact of materials in the excavation of raw materials, manufacturing process, delivery to the construction site, and operational phase of the building, some assessment tools do not cover maintenance, demolition, and disposal. Concerning materials in Indonesia, there are several challenges:

1. The methods for collecting data on materials’ life cycle. The input data are normally collected from an extensive database of building materials, which provides data referred to materials’ categories rather than to single commercial materials, which leads to unavoidable errors in the evaluation.

2. The functional unit adopted in the calculation. The choice of the functional unit greatly influences the results, as materials should be compared according to their primary function in the building, and an unsuitable unit may give misleading results.

3. The ‘quality’ of the energy considered. The calculation of materials’ embodied energy can be carried out considering the end-use energy (or delivered energy), which is the energy at the final use level, or the primary energy, which is the starting energy for the production of the end use energy (including the losses due to transformation and distribution). No explicit agreement exists on the type of energy to be considered for embodied energy determination.

• Opportunities and Strategies in Indonesia

Currently, several software can reduce the level of material waste in the aspect of determining cutting patterns and waste management features. For example, Optiwaste, which PTPP developed, has been used by projects in Indonesia.

Conclusion 

As we make global progress in reducing building energy consumption, we need to address energy from materials to reach our Carbon Mitigation goals. When we identify the material classification and categorization as green material at the end of its optimal use period, one cannot only look at the final product. We must pay attention to several things, such as how much energy is used to produce the material, how much waste is generated from the production process, and whether there is potential for reuse or must be immediately discarded without being able to be recycled. Users' advantages when using green materials are reducing costs in maintaining buildings or replacing materials, supporting energy efficiency in buildings, design flexibility, etc.

For the selection of green materials that will be re-used in the buildings, there are several things that can be considered, namely:

1. Maximize the use of local green materials available in Indonesia to ensure a small carbon print.

2. Select the alternative green materials that must still refer to the legality supporting documents and ecolabel by the green building assessment criteria parameters.

 Source

Edge learn. Designing for Greater Efficiency (DfGE). Retrieved from https://learn.edgebuildings.com/course/

Franzoni, E. (2011). Materials selection for Green Buildings: Which tools for engineers and architects? Procedia Engineering, 21, 883–890. Retrieved from https://doi.org/10.1016/j.proeng.2011.11.2090

Mustika, M., & Dwijendra, A. N. K. Preliminary study of green material for green building in Bali. International Journal of Engineering and Emerging Technology. Retrieved from https://ojs.unud.ac.id/index.php/ijeet/article/view/IJEET.2021.v06.i01.p03

Sulistiawan, A. P. (2020). Penilaian Greenship Gbci dalam Penerapan Reuse Material di Café Day N Nite Bandung. Jurnal Arsitektur TERRACOTTA, 2(1). Retrieved from https://doi.org/10.26760/terracotta.v2i1.4342