In residential, commercial and industrial buildings, overhead water tanks are one of the essential components and basic requirements. Overhead tanks are designed to store water at a height above the ground level and ensure a pressurised and steady water supply through gravity to various parts of the building. This article discusses the important aspects of overhead water tanks in detail, so keep reading to learn about these technical features.
Brief on Overhead Water Tanks
Overhead water tanks are installed at elevated levels, mostly on rooftops or specially constructed towers, to use gravitational force to supply water. They are important water distribution systems in buildings, ensuring that water flows through pipes in taps and other outlets without the need for additional pumps. When the area is limited or there is undesirable water pressure, overhead water tanks are a vital part of the project.
Overhead Tank Design
Overhead tank design involves several key considerations to ensure it functions safely and effectively. The main aspects are material selection, structural integrity, shape, size and foundation.
Let’s discuss these in detail.
1. Material Selection
Overhead tanks are commonly made from materials like concrete, steel or plastic. There are advantages and drawbacks to each of these materials.
- Concrete tanks: They are strong and durable and offer great resistance to weathering and leakage. However, they are heavy and need strong structural support and may be prone to cracking over time.
- Steel tanks: They are lightweight and easier to install compared to concrete tanks. They are resistant to cracking, but might need protective coatings to prevent corrosion, particularly in coastal or humid environments.
- Plastic tanks: Plastic tanks are the most lightweight, cost-effective and easy to install. They are resistant to corrosion and are available in various sizes and shapes. They may degrade over time due to exposure to ultraviolet (UV) light if not treated properly.
2. Structural Integrity
The structural design of an overhead water tank must consider the load of the stored water, which can be huge. The tank must be designed such that it carries static loads and dynamic loads, like wind or seismic forces depending on the location. It also involves ensuring the tank foundation can bear the total load without excessive settlements, buckling or failure.
3. Shape and Size
The shape of the tank is often rectangular, cylindrical or spherical. Each shape has its own structural advantages which are mentioned briefly below.
- Rectangular tanks: Easier to construct with concrete, especially for large capacity overhead tanks, but requires careful attention to internal stresses and may be challenging to clean.
- Cylindrical tanks: They offer great structural stability and are used for both steel and plastic tanks.
- Spherical tanks: Although they are more difficult to design and build, they offer the best stress distribution.
The size of the tank is determined by the demand for water, which depends on the number of occupants in the building, the number of plumbing fixtures, and other specific water usage factors.
Estimating the Capacity of Overhead Water Tanks
Calculating the overhead tank capacity is vital to ensure an adequate water supply. It is generally based on the factors mentioned below:
1) Water Demand Estimation
The water demand for a building depends on the type of occupancy, i.e. residential, commercial or industrial and the number of users. For example, in a residential building, the per capita water requirement might be calculated at 135 litres per person per day, as per standard guidelines. The total demand can be estimated by multiplying this by the number of occupants.
2) Peak Demand Considerations
Overhead tank design should be such that they can meet the peak demand scenarios, like the morning and evening times when the water usage is normally highest. The overhead tank capacity should be sufficient to handle these peak times without getting empty.
3) Settings for Fire Fighting
Majorly for commercial or industrial buildings, the capacity of the overhead water tank must also account for water required in case of a fire emergency. In residential buildings, there must also be sufficient water capacity for emergency situations. In these cases, the fire safety regulations may dictate a minimum volume of stored water dedicated to firefighting purposes.
Cleaning Services and Maintenance
Overhead water tank cleaning is important to ensure the water remains safe for consumption and the tank remains in good structural condition. Regular cleaning and inspection are vital components of this maintenance.
Over time, overhead tanks can accumulate sediments, algae and other contaminants that may compromise water quality. Regular cleaning is necessary to remove these deposits and ensure that water remains potable.
Cleaning Process of Overhead Water Tanks
The following steps must be followed for the overhead water tank cleaning:
- Draining the tank: The tank is emptied, either by using the water until it’s depleted or by manual/ pump draining.
- Scrubbing: The interior surfaces of the overhead tank are cleaned to remove any sediments or biological growths. Special brushes and non-toxic cleaning agents are used for this purpose.
- Disinfection: After scrubbing, the tank is disinfected using chlorine or other approved disinfectants, which kills any remaining microorganisms.
- Rinsing and Refilling: The tank is thoroughly rinsed to remove any cleaning agents or disinfectants and is then refilled with fresh water.
Frequency of Cleaning
The frequency of the overhead water tank cleaning depends on the type of tank, the local environmental conditions, and the quality of the incoming water. It is generally recommended that overhead tanks be cleaned at least once every six months. In areas with poor water quality or high sediment content, more frequent cleaning may be necessary.
Structural Inspections
Just like cleaning, regular structural inspections are essential. These inspections should check for signs of cracking, corrosion, and other structural damage that could compromise the integrity of the tank. Any issues found should be quickly repaired to avoid more serious problems.
Overhead water tanks are an important part of the infrastructure in buildings, providing a reliable water supply through gravity-fed systems. The design and capacity of these tanks must be carefully planned to meet the needs of the building while assuring structural integrity. Regular maintenance, like cleaning and inspections, is important to keep the water safe and the tank in good working condition. By following best practices in design, capacity planning and maintenance, overhead water tanks can provide many years of reliable service.
Consult our team of experts at Brick & Bolt, to know the technical aspects and use of overhead water tanks, whether it’s for residential, commercial or industrial buildings.