Step-by-step procedure to comply with the GRIHA Criteria 14: use of low-flow fixtures

Use of low-flow fixtures is an effective way to reduce water consumption in buildings. The GRIHA criterion 14 focuses on the use of low-flow fixtures and systems to ensure the reduction in building water consumption. This criterion specifies the use of low-flow fixtures, and the intent is to reduce water demand by 30%, 50%, and 70% below the GRIHA base case, which is mandatory to comply with. In this article, we will discuss step-by-step procedure to calculate water use reduction using low-flow fixtures.

Step 1: Determine the Building Occupancy and Working Days The first step in calculating water use reduction is to determine the building occupancy and working days. For example, if a building has a total occupancy of 4898 people and operates for 365 days a year, this information will be required to proceed with the calculations.

Step 2: Determine the Fixtures and Flow Rates The next step is to determine the fixtures installed in the building and their flow rates. It is important to include all the fixtures that consume water, including water closets, kitchen faucets, waterless urinals, showers, urinals, and lavatory faucets. Also, it is necessary to check the manufacturer’s specification sheet for each fixture, which indicates the flow rate (in liters per second or liters per minute) at a design pressure of 45 psi for faucets.

Step 3: Determine the Number of Uses and Water Consumption After identifying the fixtures and flow rates, the next step is to determine the number of uses and water consumption of each fixture. For example, if a building has four water closets (solids) with a flow rate of 3 liters per flush and is used 10 times a day, the daily water consumption of these fixtures will be 120 liters (4 fixtures × 3 liters per flush × 10 uses). Similarly, the same procedure is applied for all the fixtures, and the daily water consumption of each fixture is calculated.

Step 4: Calculate the Daily Water Consumption After calculating the daily water consumption of each fixture, the next step is to add up the total daily water consumption of all fixtures. The total daily water consumption will give an idea of how much water is used by the building every day.

Step 5: Calculate the Annual Water Consumption To determine the annual water consumption, multiply the daily water consumption by the number of working days in a year. For example, if the daily water consumption of a building is 244900 liters, then the annual water consumption will be 89388500 liters (244900 liters per day × 365 days).

Step 6: Calculate the Water Use Reduction To calculate the water use reduction using low-flow fixtures, use the following formula:

Water use reduction (%) = [Annual water demand (Base case) – Annual water demand (design case)] / Annual water demand (Base case) x 100

For example, if the annual water demand (base case) is 303027015 liters and the annual water demand (design case) is 89388500 liters, the water use reduction will be 70.50%.

Step 7: Provide Documentation To comply with the GRIHA criterion 14, it is essential to provide documentation that demonstrates compliance with the appraisals. This documentation should include calculations, manufacturer’s specification sheets for each fixture, purchase orders reflecting full quantities for the low-flow fixtures used in the project, and photographs with descriptions of the measures implemented.

In conclusion, using low-flow fixtures is an effective way to reduce water consumption in buildings. To comply with the GRIHA criterion 14, it is important to calculate the water use reduction using low-flow fixtures and provide proper documentation to demonstrate compliance. By following the step by step procedure mentioned above, building owners