Diesel Exhaust Fluid (DEF) Storage — ISO 22241 Compliant System Selection

Storing DEF? Start Here

Diesel Exhaust Fluid (DEF) is a blend of 32.5% urea and 67.5% deionized water used in diesel engines to reduce emissions. When storing DEF, the main concern isn't corrosion but contamination. Even tiny amounts of metals like copper or zinc can damage your engine's catalyst system. So, it's crucial to use the right materials and follow ISO 22241 standards to keep your DEF pure and your equipment running smoothly.

Can you store it in a poly tank?

Yes, you can store DEF in high-density linear polyethylene (HDLPE) or cross-linked polyethylene (XLPE) tanks. These materials are compatible with DEF, but you must ensure all tank fittings and gaskets meet ISO 22241 standards, specifically using 316 stainless steel and EPDM gaskets.

Contamination Control

Contamination is the biggest threat to DEF storage. Ensure your tank and all components are free from metals like copper and zinc, which can ruin the DEF and cause engine issues. Always use new, dedicated tanks and fittings to avoid contamination from previous contents.

The safety that actually matters

• Use only ISO 22241-approved materials for all wetted parts.
• Protect your DEF from extreme temperatures: keep it between 12°F and 86°F.
• Regularly inspect tanks and fittings for signs of contamination or damage.

Common questions

Can I use a water tank for DEF?

Only if it's a new, never-used HDLPE or XLPE tank with the correct fittings and gaskets. Previously used tanks are not suitable.

Why does DEF go bad?

DEF degrades when exposed to high temperatures, which can cause urea to break down into ammonia. Keep it cool and shaded to maintain its quality.

Do I need secondary containment?

While not legally required, secondary containment is recommended to prevent costly cleanups in case of a spill.