On-site fleet refuelling is the commercial-operator pattern where the fuel truck comes to the yard or job site.

Concept: DEF storage, shelf life, and contamination prevention

Storage:

• Optimal: 12°F / -10°C to 86°F / 30°C; freezing does not damage DEF (thaws fine in vehicle SCR heaters).
• Shelf life: 12–24 months at constant temperature ≤30°C; significantly degraded above 35°C (each 5°C above ~30°C cuts shelf life in half).
• Materials: stainless steel, HDPE, polypropylene OK. NOT compatible: mild steel, aluminum, copper, brass, zinc — DEF is corrosive to non-ferrous metals.

Contamination risk: Even small contamination from diesel, oil, coolant, tap water, or window-wash chemical destroys SCR catalyst. Dedicated dispensing equipment (no shared funnels/hoses) is mandatory. SCR catalyst replacement: typically $4,000–$10,000+ on heavy-duty trucks.

Consumption ratio: ~2–3% of diesel volume on Class 8 highway tractors; up to ~5% on heavy-duty applications under load. Practical fleet planning: 1 USG DEF per 50 USG diesel.

Regulation: ISO 22241 (DEF specification)

ISO 22241 — DEF specification (32.5% urea, deionized water). Petro-Canada's marketing notes Air1 is API-certified to ISO 22241.

Off-spec DEF can damage SCR catalysts and trigger engine derate. Storage materials must be DEF-compatible (stainless, certain plastics) — galvanized or copper materials contaminate the fluid.

Regulation: Sulphur in Diesel Fuel Regulations (SOR/2002-254)

Federal Sulphur in Diesel Fuel Regulations under the Canadian Environmental Protection Act. ULSD = ≤15 ppm sulfur, mandatory for all on-road diesel since 2006, all off-road/non-road since 2010, locomotive/marine since 2012. All diesel sold in Canada today is ULSD (no LSD remains).

Service: Standby and prime-power generator fuelling

Supply and ongoing fuelling of stand-by and prime-power generators — diesel generators at hospitals, data centres, telecom, agricultural, and commercial sites; propane generators for residential and small commercial. Includes day-tank top-ups, fuel-polishing.

Generator fuel-oil tanks fall under CSA B139 (specifically B139.1.1 for stationary engines) and O. Reg. 213/01; the B139 Comprehensive Inspection is commonly required for life-safety generators in ICI buildings. Diesel ages — ULSD typically has 6–12 months stable life — making periodic polishing or rotation important.