Most fire NOC applications in India are not rejected because of a missing extinguisher or a badly routed staircase. They are rejected because the fire water storage does not match what the code demands. The capacity falls short, the tank is quietly shared with the domestic supply, or the terrace tank sits over the wrong tower.
The National Building Code of India 2016, Part 4 (Fire and Life Safety), settles all of this through Table 7, “Minimum Requirements for Fire Fighting Installations.” This guide breaks down what that table asks for: how much water you need, where it has to sit, how it feeds the pumps, and the design rules that decide whether your installation clears inspection.
The Two-Tank System NBC Expects
NBC does not treat fire water as one lump sum. It splits the requirement across two separate storages, and both have to exist for most buildings above 15 m:
- Underground static water storage tank – this is the reserve. It sits at ground or basement level, feeds the fire pumps, and holds the bulk of the volume, anywhere from 25,000 to 200,000 litres depending on occupancy and height.
- Terrace tank – this is the head. It sits on the roof over the respective tower and supplies the wet riser or down comer instantly, before the main pumps come up to pressure. It is far smaller, typically 5,000 to 20,000 litres.
The critical word in the code is dedicated. This water is reserved for firefighting and cannot be drawn down for flushing, gardening or a summer shortage. In practice this is enforced through the draw-off level: the domestic outlet is taken from a higher point so the fire reserve physically cannot be emptied by daily use.
Why Building Height Decides Everything
Before you can size anything you need the height band. NBC 2016 uses 15 m as the line between an ordinary building and a high-rise, and requirements step up sharply after that.
| Building Height | What Is Typically Triggered |
| Below 15 m | Extinguishers, first-aid hose reel, down comer in many occupancies, modest underground storage |
| 15 m to 24 m | Wet riser, yard hydrant, automatic sprinkler, fire pump sets, terrace tank |
| 24 m to 30 m | Higher storage bands, larger pump sets, automatic detection and alarm |
| Above 30 m | Maximum storage bands, multiple pump sets, fire command provisions |
One point trips people up. A wet riser is a vertical pipe kept permanently charged and fed by the fire pumps; a down comer is fed by gravity from the terrace tank where a full wet riser is not mandated. They are not interchangeable, and the tank arrangement differs for each.
Fire Water Tank Capacity as per NBC 2016
Below are the storage figures from Table 7 for the occupancies that come up most often. All values are in litres.
Residential – Dormitories and Apartment Houses (A-4)
| Height Band | Underground Static Tank | Terrace Tank |
| Less than 15 m | 5,000 | Not required |
| 15 m to 35 m | 25,000 | As per system design |
| Above 35 m up to 45 m | 75,000 | 5,000 |
| Above 45 m up to 60 m | 150,000 | 10,000 |
| Above 60 m | 200,000 | 10,000 |
Business Buildings (E) – Offices and IT
| Height Band | Underground Static Tank | Terrace Tank |
| Less than 10 m | 10,000 | Not required |
| 10 m to 15 m | 50,000 | 5,000 |
| 15 m to 24 m | 100,000 | 10,000 |
| 24 m to 30 m | 150,000 | 20,000 |
| Above 30 m | 200,000 | 20,000 |
Mercantile Buildings (F) – Retail and Malls
| Height Band | Underground Static Tank | Terrace Tank |
| Below 15 m, G+1, floor area above 500 sq m | 20,000 | Not required |
| Below 15 m, more than G+1 | 25,000 | Not required |
| 15 m to 24 m | 100,000 | 10,000 |
| 24 m to 30 m | 200,000 | 20,000 |
| Underground shopping complex (F-3) | 150,000 | 10,000 |
Institutional (C-1) – Hospitals and Nursing Homes
| Height Band | Underground Static Tank | Terrace Tank |
| Below 15 m, plot area above 1,000 sq m | 75,000 | 10,000 |
| 15 m to 24 m | 100,000 | 10,000 |
| Above 24 m up to 45 m | 150,000 | 20,000 |
Storage Buildings (H) and Car Parks
| Building | Underground Static Tank | Terrace Tank |
| Below 15 m, area above 250 sq m, ground floor | 50,000 | 10,000 |
| Below 15 m, G+1 | 75,000 | 10,000 |
| More than G+1 | 100,000 | 10,000 |
| Multi-level car parking | 150,000 | 10,000 |
One provision quietly adds volume to almost every project. Where the basement area exceeds 200 sq m, an additional 5,000 litres of underground storage and 5,000 litres of terrace storage are added on top of the table figure, and sprinklers plus a down comer are pulled in even for occupancies that would otherwise be exempt. If a basement is added late in the design, the tank sizing has to be revisited.
Pump Capacity Is Tied to the Tank, Not Chosen Separately
Table 7 pairs each storage band with a specific pump set, so the tank and the pump room have to be planned together:
- Mid-range buildings – one electric plus one diesel standby pump at 1,620 litres/min, with a 180 litres/min jockey pump.
- Larger buildings – one electric plus one diesel standby at 2,280 litres/min, plus a 180 litres/min jockey pump.
- High-rise above 30 m – two electric plus one diesel standby at 2,280 to 2,850 litres/min, with two jockey pumps.
The code also fixes one pump set for every 100 hydrants or part thereof, capped at two sets. A useful alternative sits in the notes: instead of a second pump set, you may provide an additional diesel pump of the same capacity and double the tank capacity. That is a real design lever when pump room space is tight but tank space is not. Where sprinklers are installed they must be fed from both the underground static tank and the terrace tank.
Design Rules That Are Easy to Miss
- Depth limit – an underground fire water tank shall not be more than 7 m deep. Deeper tanks create suction problems and cannot be desilted properly.
- Two compartments – every tank should have at least two compartments so one side can be cleaned while the other stays charged. A single-compartment fire tank means zero fire water during maintenance.
- Terrace tank location – the terrace tank must sit over the tower it serves. In a multi-tower project, one shared terrace tank is a common and expensive mistake.
- Access – the tank and pump room must be reachable by the fire brigade, with the inlet connection accessible from the approach road.
- Stagnation – fire water sits stagnant for months. The tank has to hold it without corroding or shedding debris into the suction line.
Where Fire Tank Projects Actually Fail
From an installation standpoint, the same problems repeat across sites:
- A leaking RCC tank that has lost 10 to 15 percent of its rated volume through seepage, so the building silently drops below its NBC figure.
- A mild steel fire tank that has rusted internally after years of stagnant storage, sending scale into pump impellers and choking sprinkler heads.
- Domestic and fire storage sharing one chamber with no draw-off level arrangement, so the reserve is routinely consumed.
- A basement added during construction without recalculating the storage, leaving the project 10,000 litres short at inspection.
Choosing the Right Tank Construction for Fire Water Storage
NBC specifies how much water and where. It does not tell you what to build the tank from, and that decision has a direct effect on whether the building is still compliant five years later.
RCC tanks are cheap to pour, but cracks and construction joints develop over time and repairing them means breaking concrete inside an occupied building. Mild steel tanks go up quickly but corrode from the inside when water sits still, which is exactly the duty cycle of a fire reserve.
Modular sectional tanks solve a different set of problems. An SMC panel tank is built from moulded composite panels bolted together on site over a level plinth, so capacity can be matched exactly to the NBC figure instead of rounding up to the nearest concrete pour. Because the panels travel flat and are assembled in place, the tank can be carried through a standard doorway and built inside a basement, plant room or terrace, which is the single biggest reason panel construction dominates retrofit fire tank work. An internal partition gives you the two-compartment arrangement the code expects, and the composite material does not rust in stagnant water, so the suction line stays clean.
Sizing works the same way as any other storage application. Our guide to panel tank sizes and capacities explains how the panel module grid translates into a finished volume, and the step-by-step installation walkthrough covers the plinth and levelling work that has to be right before the first panel goes up. If you are weighing this against a concrete build, the comparison with RCC and overhead tanks sets out the trade-offs.
Compliance Checklist Before You Apply for Fire NOC
- Occupancy group and height band confirmed against Table 7 of NBC 2016 Part 4.
- Underground static storage matches or exceeds the table figure, with the basement addition included where applicable.
- Terrace tank provided over each respective tower, at the correct capacity.
- Fire storage separated from domestic storage, with the draw-off level arrangement shown on the drawing.
- Minimum two compartments in every fire tank.
- Underground tank depth within 7 m.
- Pump set capacity and standby diesel pump matched to the storage band.
- Sprinkler system fed from both underground and terrace storage.
- Fire brigade inlet and pump room accessible from the approach road, with tank test certificates available for the file.
State Rules Can Be Stricter Than NBC
NBC 2016 is a model code. It becomes binding only when a state or municipal authority adopts it into local building bye-laws, and several states impose more than the NBC baseline: larger storage for specific occupancies, yard hydrants at lower heights, or extra approvals for underground tanks. The Authority Having Jurisdiction, usually the state fire services department, has the final say, so confirm the local amendment before finalising the tank drawing. The code figure is the floor, not the ceiling. Panel construction is used across a wide range of building types for exactly this reason: capacity can be adjusted to whatever the local authority insists on without redesigning the structure around it.
Frequently Asked Questions
1. How often should a fire fighting water tank be inspected and cleaned?
Plan a visual and level check every month and a full drain-and-clean at least once a year, ideally after the monsoon when sediment carry-in is highest. This is where the two-compartment requirement pays for itself: one side stays charged, so the building never sits without fire water during cleaning.
2. What happens if the tank capacity falls short during a fire NOC inspection?
The NOC is withheld until the shortfall is corrected, and in occupied buildings this often surfaces at renewal rather than first approval. The usual remedy is an additional tank in whatever space is available, which is why a modular tank that can be built to an odd, specific volume retrofits more easily than a fresh concrete pour.
3. Can a fire water tank be installed inside a basement or plant room?
Yes, and it is very common. The constraint is access, because the tank has to get in through whatever opening already exists. Site-assembled panel construction handles this: individual panels pass through a standard doorway and the tank is built inside the room, with plinth, levelling and perimeter working space planned in advance.
4. Does NBC allow the required fire water storage to be split across more than one tank?
The code specifies total volume rather than mandating a single vessel, and multiple interconnected tanks are routinely accepted where site conditions demand it. Confirm the arrangement with your Authority Having Jurisdiction, and make sure the suction and interconnection design lets the pumps draw the full combined volume.