Overview
EN 1200:2005 (CEN) specifies requirements for trisodium orthophosphate (Na3PO4) when used in the treatment of water intended for human consumption. The standard describes identification, physical and chemical properties, purity criteria, required test methods, and rules for labelling, transportation and storage. It also includes practical information on use in water treatment (Annex A) and safety rules (Annex B). EN 1200:2005 supersedes EN 1200:1997.
Key identifiers included:
- Chemical name: Trisodium orthophosphate (synonym: sodium phosphate, tribasic)
- Empirical formula: Na3PO4; relative molecular mass 164.0
- CAS: 7601-54-9; EINECS: 231-509-8
- Typical properties: 1% solution pH ≈ 12; solubility ≈ 120 g/L at 25 °C.
Key topics and technical requirements
- Scope and description: Commercial forms (powder, granules, clear solutions), bulk density ranges and solution densities.
- Composition: On a dry-mass basis the product shall contain:
- Phosphate (expressed as P2O5): (41 ± 1.0) %
- Sodium (expressed as Na2O): (53 ± 1.0) %
- Impurities limits (examples):
- Sulfate (SO4 2–): max 500 mg/kg
- Fluoride (F–): max 10 mg/kg
- Trace chemical parameters (examples):
- Antimony, arsenic, cadmium, selenium: max 3 mg/kg
- Chromium, lead, nickel: max 10 mg/kg
- Cyanide: max 5 mg/kg; mercury: max 1 mg/kg
- Test and sampling methods:
- Sampling: ISO 3165, ISO 6206, ISO 8213 guidance for solids and liquids (drums, tanks, tankers).
- Main composition: alkalimetric titration (pH endpoints ~4.45 and ~9.22) to determine P2O5 and Na2O.
- Impurities and trace elements: methods referenced include EN 1483, EN ISO 11885 (ICP), EN ISO 11969 (hydride AAS), ISO methods for fluoride, sulfate and cyanide.
- Labelling, storage and transport: requirements and safe-handling rules are detailed; Annex B is normative on safety.
Applications and users
Practical uses:
- Water utilities and treatment plant operators for corrosion control, pH adjustment and phosphate dosing.
- Chemical manufacturers and suppliers for product specification, QC and conformity assessment.
- Analytical laboratories performing quality control tests and regulatory compliance checks.
- Regulators and public health authorities referencing purity, impurity limits and testing protocols for chemicals used in drinking water.
Keywords: EN 1200:2005, trisodium orthophosphate, water treatment, drinking water standard, sodium phosphate, purity criteria, test methods, sampling, labelling, safety.
Related standards
Normative references cited in EN 1200:2005 include (selected): EN 1483, EN ISO 3696, EN ISO 11885, EN ISO 11969, ISO 2997, ISO 3360, ISO 3165, ISO 8213. These specify analytical and sampling procedures used to verify conformity.