IS 3370:2021 Part 1 is the Indian Standard (BIS) for concrete structures for storage of liquids - part 1: general requirements. This part of the code specifies the general requirements for the design and construction of plain, reinforced, and prestressed concrete structures intended for the storage of liquids, emphasizing durability, crack control, and water-tightness.
Lays down general requirements for the design and construction of concrete structures for the storage of liquids.
Concrete grade, w/c, cover, crack-width, permissible tensile/compressive stresses and joint spacing for water-retaining concrete structures.
| Reference | Value | Clause |
|---|---|---|
| Min concrete grade — liquid-retaining structures | M30 | Cl. 7.1 |
| Max water-cement ratio | 0.45 | Cl. 7.1 |
| Min cement content | 320 kg/m³ | Cl. 7.1 |
| Min nominal cover — face in contact with liquid | 40 mm | Cl. 8.1 |
| Min nominal cover — other faces | Per IS 456 exposure category | Cl. 8.1 |
| Crack width limit — severe exposure (liquid face) | 0.2 mm | Cl. 9.2 |
| Crack width limit — moderate exposure | 0.3 mm | Cl. 9.2 |
| Permissible tensile stress — Fe415 (direct, σst) | 150 N/mm² | Cl. 9.3 (Table 4) |
| Permissible tensile stress — Fe415 (bending, σst) | 190 N/mm² | Cl. 9.3 (Table 4) |
| Permissible tensile stress — Fe500 (direct) | 180 N/mm² | Cl. 9.3 (Table 4) |
| Permissible tensile stress — mild steel (Fe250) | 115 N/mm² (direct), 125 N/mm² (bending) | Cl. 9.3 (Table 4) |
| Min steel — each face/direction (mass-control) | 0.24 % (Fe415/500) × gross area | Cl. 8.2.1 |
| Min steel — walls 100–500 mm (each face) | 0.20 – 0.30 % (interpolated by thickness) | Cl. 8.2.1 (Table 3) |
| Joint spacing — movement joints (typical) | ≤ 7.5 m (full movement); ≤ 15 m partial | Cl. 10.2 |
| Joint spacing — construction joints | Designed; typical 5–7 m | Cl. 10.3 |
| Permissible compressive stress — concrete (M30, direct) | 8 N/mm² | Cl. 9.4 (Table 5) |
| Permissible compressive stress — concrete (M30, bending) | 10 N/mm² | Cl. 9.4 (Table 5) |
| Hydrostatic test — duration after curing | 7 days minimum | Cl. 11 |
| Permissible drop in water level (test) | ≤ 1/500 of average depth (or 40 mm) | Cl. 11 |
| Design method permitted | Working stress (Cl. 9) or limit state (refer Part 2) | Cl. 6 |
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Minimum Concrete Grade | M30 | 28 MPa (~M28) specified compressive strength (f'c) | ACI 350-20 |
| Maximum Water-Cement Ratio (Severe Exposure) | 0.45 | 0.45 | ACI 350-20 |
| Minimum Nominal Cover (Liquid Face, Severe Exposure) | 45 mm | 50 mm (2 in.) | ACI 350-20 |
| Design Crack Width Limit (Liquid Face) | Not explicitly defined; controlled indirectly by limiting steel stress to 130 MPa (for HYSD bars). | 0.25 mm (0.010 in.) | ACI 350-20 |
| Load Factor for Fluid Pressure (ULS) | 1.5 | 1.4 | ACI 350-20 |
| Watertightness Test Duration | 7 days | Generally 24 hours (after a stabilization period), but can vary. | ACI 350.1-10 |
| Minimum Cement Content (Severe Exposure, 20mm aggregate) | 340 kg/m³ | 320 kg/m³ (For comparable XD1 exposure class) | EN 1992-1-1:2004 |