Full explanation
DSTU 7688:2015 parameters: cetane number ≥51, sulfur content ≤10 mg/kg (Euro-5 class), density at 15°C 820–845 kg/m³, cloud point ≤-5°C (winter) / +5°C (summer), ash ≤0.01%, water content ≤200 mg/kg. Grades: DP-C (summer, +5°C CFPP), DP-F (winter, -20°C CFPP), DP-B (arctic, -32°C CFPP), DP-E (all-season). Typical failures in retail (non-branded stations in South/East): (a) adulteration with kerosene or used oil (2022-2024 rose from 3% to 20% per ICE data), (b) wrong seasonal grade (DP-C in February → fuel line freezes at -8°C), (c) water above limit. Verification: DSTU 7688 certificate of conformity from the supplier (OKKO, WOG, SOCAR, KLO have digital certs on their websites); for bulk — quality passport + invoice with lab ID. The diesel-procurement-timing calculator asks for the grade to correctly size the winter 200+ h blackout reserve. Source: energy-kb.ts §diesel_quality + DSTU 7688:2015.