ISO 3427:1976

Overview

ISO 3427:1976 specifies the apparatus and step‑by‑step procedures for taking a laboratory sample of gaseous halogenated hydrocarbons (liquefied gases) from bulk containers (cylinders, drums, tanks). The standard focuses on safe, repeatable sampling from the liquefied phase using a cleaned, dried and evacuated stainless steel sample cylinder designed to withstand an internal pressure of at least 3 MPa (30 bar). A sampling assembly diagram and practical conditioning steps are provided to ensure representative, contaminant‑free samples for analysis.

Key topics and technical requirements

• Scope and principle
  • Sampling is taken only from the liquid phase of halogenated hydrocarbons.
  • The sample cylinder must be easy to clean and compatible with the product.
• Sample cylinders
  • Stainless steel construction, pressure rated to ≥ 3 MPa (or per product regulations).
  • Two permitted cylinder types: (a) with two needle valves and an internal dip tube; (b) with a single valve and no internal tubes.
• Ancillary equipment
  • Connecting tube (preferably stainless steel) with threaded unions and chemically resistant washers.
  • Vacuum pump capable of reducing to about 100 Pa (1 mbar).
  • Electric oven controllable at 105–110 °C, desiccator with desiccant, cooling bath, compressed dry nitrogen, and a balance accurate to ±1 g.
• Procedure highlights
  • Clean, dry, evacuate and weigh the empty sample cylinder.
  • Purge lines and cylinder with clean dry nitrogen to remove air and moisture.
  • Bake assembly in oven (105–110 °C) and evacuate to ~100 Pa for specified durations.
  • Connect to the liquid‑phase valve of the container (using correct orientation depending on cylinder type), fill to the allowed filling ratio, and reweigh to confirm fill.
  • If overfilled, carefully discharge excess liquid per the standard’s method and recheck pressure-tightness.
• Compatibility & sealing
  • Use washers and materials not attacked by the halogenated hydrocarbon being sampled.
  • Follow any product‑specific international or national filling and safety limits.

Applications and users

ISO 3427 is used by:

• Chemical testing and QC laboratories performing compositional or purity analyses of halogenated refrigerants, solvents and industrial gases.
• Manufacturers and suppliers of halogenated hydrocarbons for batch release testing and transport sampling.
• Regulatory and compliance teams verifying representative samples for safety, transport and environmental reporting.
• Research institutions and material testing facilities where accurate, contamination‑free sampling from pressurised liquefied gas containers is required.

Keywords: ISO 3427, gaseous halogenated hydrocarbons, liquefied gases, sampling, sample cylinder, stainless steel cylinder, vacuum pump, nitrogen purge, liquid‑phase sampling.

Related standards

Other ISO documents referenced in the annex:

• ISO/R 1393 - Determination of acidity (liquids)
• ISO/R 1394 - Determination of cloud point (liquids)
• ISO 2209 - Sampling (liquids)
• ISO 2210 - Determination of residue on evaporation (liquids)

For product‑specific filling ratios and additional safety requirements, consult the relevant individual international standards for the particular halogenated hydrocarbon.