Constructing a building is not merely about erecting walls and a roof. In today’s modern era, environmental considerations have become a top priority to ensure that buildings remain comfortable while minimizing harm to the ecosystem.
One of the most critical aspects to prepare is Green Open Space (RTH). Understanding how to calculate green open space from the planning stage is essential to ensure your project complies with environmental standards and government regulations.
Without proper calculation, a building risks becoming an inefficient “heat island” and may face difficulties in obtaining permits.
What Is Building Green Open Space (RTH)?
Simply put, building Green Open Space (RTH) refers to areas within a plot or building site that are left open without permanent roofing. These areas are intended for plant growth, such as gardens, grass, or trees.
At the building scale, RTH is not limited to front yards alone. Today, the concept of RTH has expanded to include rooftop gardens (roof gardens) or water infiltration areas around parking zones.
Essentially, RTH functions as a small “lung” for the building, helping to maintain proper air circulation and water absorption.
The Importance of Green Open Space in Green Buildings
The implementation of RTH is a fundamental requirement when adopting the green building concept. The key reasons include:
Improving Environmental Quality and User Comfort
The presence of greenery has been proven to reduce surrounding temperatures. Plants absorb solar heat and release oxygen, creating a cooler and more comfortable atmosphere.
For building occupants or users, green views can also reduce stress levels and enhance productivity.
Supporting Energy Efficiency and Water Management
RTH plays a major role as a natural rainwater infiltration area. With open soil surfaces, rainwater can seep directly into the ground, reducing the burden on drainage systems and helping to prevent flooding.
In addition, cooler building temperatures resulting from vegetation reduce reliance on air conditioning, leading to significant electricity cost savings.
Contribution of RTH to Green Building Assessment and Certification
If you plan to apply for green building certification (such as Greenship or EDGE), the percentage of RTH is a major assessment criterion.
The larger and higher-quality the RTH provided, the greater the chances of achieving sustainable building certification.
How to Calculate Building RTH
Many people assume that calculating RTH simply means leaving empty land. In reality, there are formulas and technical standards that must be followed. The basic steps include:
- Determine Total Land Area: Identify the total size of the land plot.
- Check the Green Base Coefficient (KDH): Local governments typically specify a KDH value in building permits. For example, if the KDH is set at 20%, then 20% of the total land area must be allocated as green space.
- Apply the Basic Formula:
RTH Area = Total Land Area × KDH Percentage - Identify Types of RTH: Calculate areas that are truly open (without concrete paving). If using perforated paving blocks (grass blocks), usually only a portion of the area is counted as RTH, depending on local regulations.
Understanding how to properly calculate building RTH will help you avoid fines or obstacles during the processing of Building Construction Permits (IMB) or Building Approval (PBG). Be sure to record every section of land that functions as a water infiltration area.
Developing an environmentally friendly building strategy does involve technical challenges. If you encounter difficulties in determining how to calculate green open space or want to ensure your project complies with applicable green building certification standards, Sarana Hijau Lestari is ready to assist.
As a sustainability consulting expert, Sarana Hijau Lestari provides services ranging from simulations and energy audits to green building certification support.
We help optimize land use so it remains functional while staying green and sustainable. With our guidance, you no longer need to worry about RTH calculation formulas or other technical requirements.
Let us build a greener future together.
