IS & BIS Standards Reference, Free Online Resources, Key Reference Tables, Formula Quick Card, 30-Term Glossary & Full Calculator Index — Everything in One Place
The following standards govern concrete mix design, material testing, structural design, and production in India. All are published by the Bureau of Indian Standards (BIS) and are available for purchase from the BIS portal or state BIS offices.
IS standards are available for purchase from the Bureau of Indian Standards portal at bis.gov.in (online store). Individual standards cost ₹300–1,200 depending on the document. Many engineering colleges and public sector organizations have institutional BIS memberships that provide access to the full BIS catalog. Engineering professionals working on public projects are required to use the current revision — always verify the edition year before use, as several IS standards have been revised since 2015.
| Exposure | Min Grade | Max w/c | Min Cement (kg/m³) | Cover — Slab | Cover — Beam | Cover — Column |
|---|---|---|---|---|---|---|
| Mild | M20 | 0.60 | 300 | 20mm | 20mm | 40mm |
| Moderate | M25 | 0.50 | 300 | 25mm | 30mm | 40mm |
| Severe | M30 | 0.45 | 320 | 35mm | 45mm | 45mm |
| Very Severe | M35 | 0.40 | 360 | 45mm | 50mm | 50mm |
| Extreme | M40 | 0.35 | 380 | 65mm | 75mm | 75mm |
| Grade Range | Standard Deviation S (MPa) | k×S Margin (k=1.65) | fcm for Min Grade in Range |
|---|---|---|---|
| M10, M15 | 3.5 | 5.78 | M10: 15.78 | M15: 20.78 |
| M20 | 4.0 | 6.60 | 26.60 MPa |
| M25, M30, M35 | 5.0 | 8.25 | M25: 33.25 | M30: 38.25 | M35: 43.25 |
| M40, M45, M50, M55 | 5.5 | 9.08 | M40: 49.08 | M45: 54.08 |
| M60 and above | 6.5 | 10.73 | M60: 70.73 |
| MSA (mm) | 25–50mm slump | 51–75mm | 76–100mm | 101–125mm | 126–150mm | 151–175mm |
|---|---|---|---|---|---|---|
| 10mm | 208 | 215 | 222 | 228 | 234 | 240 |
| 12.5mm | 200 | 207 | 213 | 219 | 225 | 231 |
| 16mm | 196 | 200 | 206 | 212 | 218 | 223 |
| 20mm | 190 | 196 | 202 | 208 | 213 | 217 |
| 25mm | 184 | 188 | 193 | 199 | 204 | 208 |
| 40mm | 168 | 172 | 176 | 181 | 185 | 189 |
Highlighted row: 20mm MSA — most common for structural concrete. For rounded gravel: subtract ~20 L/m³. For PCE SP (WR%): multiply by (1 − WR/100).
| MSA (mm) | Zone I FA% | Zone II FA% | Zone III FA% | Zone IV FA% |
|---|---|---|---|---|
| 10mm | 40 | 44 | 48 | 52 |
| 12.5mm | 36 | 40 | 44 | 48 |
| 16mm | 34 | 38 | 42 | 46 |
| 20mm | 32 | 36 | 40 | 44 |
| 25mm | 30 | 34 | 38 | 42 |
| 40mm | 28 | 32 | 36 | 40 |