E10 and E20 are petrol with 10% and 20% ethanol. The density limits stay 720 to 775 kg/m³ at 15 °C. What changes is water: ethanol takes up water, so tanks and tank lorries must be checked with a water-finding paste suitable for ethanol-blended petrol, and any water treated at once.
The blends
| Blend | Ethanol | Standard |
|---|---|---|
| E5, E10 | up to 5%, 10% | IS 2796 |
| E12, E15 | 12%, 15% | IS 17586 |
| E20 | 20% | IS 17021 |
Density stays in the same band
MDG 2024’s specification table gives 720 to 775 kg/m³ at 15 °C for motor gasoline and for E10 to E20 alike. The daily density check, the ±3.0 kg/m³ comparison with the invoice, and Table 53B all work the same way.
Water is the real change
Ethanol mixes with water. Petrol does not. If enough water gets into a tank of blended petrol, it pulls the ethanol out into a separate layer at the bottom. The petrol above is left weaker, and the bottom layer is unfit to sell.
That is why the MDG asks for a water-finding paste suitable for ethanol-blended petrol when checking tank lorry compartments (clause 1.2 vii). An ordinary paste may not show water that has taken up ethanol.
What to do
- Keep dip pipe and fill caps tight, especially in the rains.
- Take the water dip every morning with the right paste.
- Report any water to your oil company at once (clause 1.4.1 b).
Figures here are for reference. Your oil company’s certified calibration chart, approved instruments and the Marketing Discipline Guidelines always prevail.
Questions
Do I use a different density table for E20?
The MDG gives the same density range for E10 to E20 as for plain petrol, and the density at 15 °C is found the same way, with Table 53B.
Which standards cover the blends?
MDG 2024 Annexure 7 names IS 2796 for E5 and E10, IS 17586 for E12 and E15, and IS 17021 for E20.