Overview
ISO 1552:1976 - "Liquid chlorine for industrial use - Method of sampling (for determining only the volumetric chlorine content)" specifies a controlled procedure for taking representative liquid-chlorine samples during transfer to or from tank-wagons. The standard applies only when the sampling is intended to determine volumetric chlorine content (not water content) and assumes prior agreement between parties to take two representative samples during filling at the manufacturer's premises.
Key topics and technical requirements
- Purpose: Sampling method to obtain representative samples for volumetric chlorine analysis; one sample for the customer and one retained by the manufacturer for dispute checks.
- Applicability: Only for volumetric chlorine determination; a special-case procedure exists for sampling during wagon emptying if no prior agreement was made.
- Sample containers: Steel sample bottles with a useful capacity of 1 to 10 L, fitted with a two-valve head and two dip tubes. The shorter dip tube is dimensioned so a residual gas phase of about 12–15% of bottle volume remains (prevents complete liquid fill).
- Equipment & connections: Copper or steel connecting hoses (~10 mm), needle valves and associated stainless-steel fittings; provision for safe venting to a scrubber or degassing hood.
- Leak and integrity checks: Verify gas-tightness of the sampling system and bottle heads (soap solution checks, acid-sulphuric bubbler evidence) before sampling.
- Cleaning & preparation: Clean piping and bottles with steam and dry with dry air prior to sampling.
- Filling control: Samples are normally taken during wagon filling; bottle filling is controlled and checked by weighing (to determine mass of chlorine sampled). Flow should continue for at least 10 minutes after the liquid level reaches the lower end of the short dip tube to ensure representative sampling.
- Record keeping: A sampling protocol (procès-verbal) must document method reference, any special circumstances, and any deviations or optional operations performed.
Applications and users
ISO 1552:1976 is used by:
- Chlorine manufacturers and plant quality departments for standardized sampling during loading of tank-wagons.
- Transport operators and logistics teams handling industrial liquid chlorine.
- Industrial users and procurement/quality teams receiving chlorine deliveries who require an independent sample.
- Analytical and quality-control laboratories performing volumetric chlorine determinations.
- Safety and compliance officers managing safe sampling procedures and record-keeping.
This standard supports reliable, reproducible sampling practices that reduce disputes over delivered chlorine concentration while emphasizing safety and leak-tight handling.
Related standards
- ISO 2120 - Determination of volumetric chlorine content (gravimetric method for gasified product)
- ISO 2121 - Water determination (related dosing methods)
- ISO 2202 - Water determination using an electrolytic titrator
Keywords: ISO 1552:1976, liquid chlorine sampling, volumetric chlorine content, tank-wagon sampling, steel sample bottles, gas-tight sampling, industrial chlorine.