Overview
EN ISO 8819:1995 (ISO 8819:1993) specifies a simple, qualitative procedure for the detection of hydrogen sulfide (H2S) in liquefied petroleum gases (LPG) using the lead acetate method. The procedure detects H2S at a lower limit of 4 mg H2S per 1 m³ of gas. The method is intended for on‑site assessment of H2S presence and distinguishes transient responses (e.g., methyl mercaptan) from persistent H2S staining.
Key topics and technical requirements
- Detection principle: Vaporized LPG sample is passed over moist lead acetate paper; H2S reacts to form lead sulfide, producing a colour change from yellow to black.
- Limit of detectability: 4 mg H2S / 1 m³ gas.
- Interferences: Methyl mercaptan causes a transitory yellow stain on lead acetate paper that fades within 5 minutes; other sulfur compounds present do not interfere with the test.
- Test apparatus and materials:
- Lead acetate test paper prepared by dipping filter paper into a 50 g/L aqueous lead acetate solution or commercially equivalent paper.
- Paper strip dimensions: approx. 51 mm × 9.5 mm with a 3.5 mm hole for hanging.
- Test rig includes a glass cylinder, water reservoir at 60–80 °C, stainless steel tubing and a needle valve; flow indicator measuring 2–3 L/min.
- Operating conditions: Adjust flow to 2.3 L/min ± 0.2 L/min and expose the paper for exactly 2 minutes. Flush sample lines for ~1 minute before testing.
- Sampling guidance: Prefer direct connection to the sample source; avoid rubber hoses and, where possible, avoid use of sample cylinders because of adsorption/contamination risks discussed in Annex A.
- Test reporting: Reports must include product identification, reference to EN ISO 8819, test result (H2S positive/negative or methyl mercaptan present), deviations from procedure, and test date.
- Safety note: Standard warns of hazardous materials and operations; users must follow appropriate safety and regulatory measures.
Applications
- Routine on‑site screening of LPG batches for hydrogen sulfide contamination.
- Pre‑shipment or fueling point checks where H2S odor or corrosivity is a concern.
- Quick qualitative assessment by gas producers, distributors, safety inspectors and field testing teams.
Who uses this standard
- LPG producers and distributors
- Quality control laboratories and field technicians
- Safety and regulatory inspectors concerned with gas corrosivity and odor issues
Related standards
- EN ISO 8819 is part of the suite of LPG quality and safety standards. For comprehensive compliance, users typically apply this test alongside other ISO/CEN standards covering LPG sampling, composition analysis and safety procedures.
