ISO 31120-1:2022

Overview

ISO 31120-1:2022 specifies quality requirements for injection water (IW) used in water injection systems for internal combustion engines in road vehicles. The standard defines chemical and physical limits for IW, requirements for production, storage and container materials, sampling and testing procedures, and quality assurance measures to ensure consistent, contamination-free supply.

Key topics and requirements

• Water quality limits (selected examples) - IW must meet specific analytical limits (see Table 1 in the standard), for example:
  • Electrical conductivity (25 °C): ≤ 15 µS/cm (ISO 7888)
  • pH: 5 to 8 (ISO 10523)
  • Evaporation residue: ≤ 30 mg/L (DIN 38409-1)
  • Total organic carbon (TOC): ≤ 1.2 mg/L (EN 1484)
  • Chloride (halogens): ≤ 0.5 mg/L (ISO 10304-1)
  • Other parameters: limits for nitrate, nitrite, sulfate, ammonium, chlorate, bromate, metals and non-filterable solids
  • Residual/free chlorine: ≤ 0.1 mg/L (ISO 7393-2/3)
• Materials compatibility - Recommended materials for surfaces in contact with IW include PTFE, PFA, PVDF, polyethylene and polypropylene (additive-free); materials not recommended include carbon steels, zinc-coated steels, glass and many metal containers due to contamination risk.
• Storage and handling - Containers should be well-sealed or vented with filters to prevent airborne contamination. Protect IW from sunlight and avoid storage below 5 °C (freezing considerations). Shelf life guidance by constant storage temperature:
  • <10 °C: up to 36 months
  • ≤25 °C: up to 18 months
  • ≤30 °C: up to 12 months
  • <35 °C: not recommended (1 month)

  • 35 °C: verify each batch

• Quality assurance and testing - The standard mandates sampling, testing against the parameters in Table 1, documentation, audits and procedures for handling non-conforming product.
• Operations covered - Production batches, bulk and packaged shipments, single-use and dedicated/non-dedicated bulk operations.

Applications and users

Who benefits from ISO 31120-1:2022:

• Automotive OEMs specifying IW supply requirements for water injection systems
• Water producers and suppliers producing and certifying injection-grade water
• Component and container manufacturers (tanks, hoses, valves) ensuring material compatibility
• Testing laboratories performing required analyses and issuing certificates of analysis
• Fleet operators and maintenance teams implementing correct storage and handling

Practical uses: ensuring consistent injection water quality to protect engines and aftertreatment systems, avoid contamination or corrosion, and provide reproducible performance when using water injection.

Related standards

ISO 31120-1 references several analytical and test methods, including:

• ISO 7888 (conductivity), ISO 10523 (pH), ISO 11885 (ICP‑OES for elements), ISO 10304 series (anions), ISO 7393‑2/3 (chlorine), EN 1484 (TOC), EN 872 (non-filterable solids).