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.
