ISO/TS 21256-1:2020 PDF

Overview

ISO/TS 21256-1:2020 - Fine bubble technology - Cleaning applications - Part 1: Test method for cleaning salt (NaCl)-stained surfaces - specifies a reproducible laboratory test to evaluate how ultrafine bubble (UFB) water improves the cleaning performance of high‑pressure water jets on salt‑stained steel surfaces. The procedure compares removal of NaCl deposits from a standardized steel test plate when cleaned with UFB‑augmented water versus control (plain) water, using surface salinity measurements to quantify results.

Key Topics and Technical Requirements

• Test principle: Compare density of adherent salt before and after cleaning to determine removal ratio and removal quantity.
• High‑pressure water jet: Nozzle outlet inner diameter 6 mm; outlet pressure 5–9 MPa; flow 300–400 L/h; cleaning width 250–300 mm at 2 m distance; water temperature 15–25 °C; UFB water continuously supplied during cleaning.
• Test specimen: Carbon steel flat plate, 530 mm × 530 mm × 10 mm, prepared with defined NaCl staining.
• Measurement protocol:
  • Initial salinity measured at four specified (even‑numbered) points; post‑cleaning measured at five specified (odd‑numbered) points.
  • Surface salinity meter (conductivity‑based, per ISO 8502‑9) used for density readings; instrument precision ±1% between 0 °C and 50 °C.
  • Cleaning motion: reciprocal nozzle passes (approx. 1 s per pass); ~20 repetitions typical; tests continue until target removal or residual salinity reads zero.
• Reporting and calculations: Results expressed as salt removal ratio or removal quantity derived from initial and after‑clean salinity densities. Test report must include weather, equipment, wash liquid, and measurement details.

Applications and Users

• Who uses it: UFB generator and fine‑bubble product manufacturers, third‑party test laboratories, civil/structural engineers, bridge and infrastructure maintenance teams, and procurement/specification authors.
• Practical uses:
  • Objective performance claims for UFB cleaning systems used in bridge, highway, coastal and anti‑icing salt maintenance.
  • Comparative testing in R&D to optimize UFB size and concentration for high‑pressure cleaning.
  • Supporting maintenance planning and life‑cycle corrosion mitigation strategies for steel structures.
• Value: Provides standardized, repeatable metrics to demonstrate cleaning effectiveness of ultrafine bubble water under defined hydrodynamic and environmental conditions.

Related Standards

• ISO 20480‑1 / ISO 20480‑2 - terminology and categorization for fine bubbles.
• ISO 8502‑9 - surface salinity measurement (conductivity‑based method) referenced for converting conductivity to surface salinity.

Keywords: ISO/TS 21256-1:2020, fine bubble technology, ultrafine bubble water, high-pressure water jet, salt-stained steel cleaning, surface salinity meter, cleaning performance test.