1. This limit is applicable prior to addition of cetane number improvers, if used. In case a value exceeding the limit is obtained on finished fuels in the market, ASTM D 4046 shall be used to establish the presence of nitrate containing cetane number improves. In such case the present limit for carbon residue cannot be applied. However, the use of cetane number improves does not exempt the manufacturer on meeting this requirement prior to the addition of additives.

2. When a test engine is not available or when the quantity of the sample is too small for an engine rating "Calculated Cetane Index by Four Variable Equation" by ASTM D 4737 may be used for estimation of cetane number. The error in prediction of the "Calculated Cetane Index" by this method will be less than +,-2 Cetane Number for fuels having Cetane Number within the range of 32 to 56. It may be noted that this method is not applicable to pure hydrocarbons or fuels containing cetane improvers or fuels derived from coal. For arbitration purposes, the direct determination of cetane number by means of the standardized engine test shall be used unless the buyer and the seller agree otherwise.

3. Subject to agreement between the purchaser and the supplier, a lower or higher maximum pour point and CFPP may be required for special applications and geographical areas.

4. Winter shall be the period from November to February (both months inclusive) and rest of the months of the year shall be called as summer.

5.Diesel fuel for naval applications including Merchant navy and fishing vessels of 12 metres and above in length shall have a flash point of 66^oC Min, when tested by the method prescribed in IS 1448 [P : 21] : 1970

6. Total sulphur content for HSD shall stand automatically revised as per the following schedule; although efforts will be made by the oil companies to reduce sulphur content below 1.0 percent by mass even before 1998:

7. This test shall be carried out only at the refinery or manufacturer's end and the limit for this test is meant for products prior to addition of multi-functional additives if used. However, the use of multi-functional additives does not exempt the manufacturer from meeting this requirement prior to the addition of additives.

Effective 01.04.10 FO/LDO supplies to rail fed customers is through BTPN (8 wheeler) rakes only since railways has withdrawn conventional (4 wheeler) rakes from circulation.