ISO 10298:2018

Overview

ISO 10298:2018 - Gas cylinders - Gases and gas mixtures - Determination of toxicity for the selection of cylinder valve outlets provides a consolidated, literature‑based listing of the best available acute inhalation toxicity data (LC50) for gases and vapours. The standard is intended to support the classification of pure gases and gas mixtures by inhalation toxicity so that appropriate cylinder valve outlets and safety measures can be selected.

Key topics

• Scope and purpose: Compiles validated acute‑toxicity (LC50) data from the open literature to enable toxicity classification for valve‑outlet selection.
• LC50 basis: LC50 values in the standard correspond to 1‑hour exposures (rat data preferred). Where necessary, time‑adjustment principles (Haber’s rule and variants) are applied to align different exposure durations.
• Toxicity subdivisions: Defines toxicity groups used for valve selection and transport:
  • Subdivision 1: non‑toxic (LC50 > 5 000 ppm)
  • Subdivision 2: toxic (200 ppm < LC50 ≤ 5 000 ppm)
  • Subdivision 3: very toxic (LC50 ≤ 200 ppm)
• Mixture calculation: Provides an additive calculation method for mixtures using the mole fraction of each toxic component and its LC50 (1/LCmix = Σ (Ci / LC50,i)), enabling classification of gas mixtures without new animal testing.
• Data quality and selection: Annex A describes the algorithm for selecting LC values (preferred animal species, time adjustments, read‑across, use of LD values only as last resort).
• Reference data: Annex B lists LC50 values and literature sources for many toxic gases and vapours.

Practical applications

• Selecting correct cylinder valve outlets and fittings based on gas toxicity to reduce risk during handling and connection.
• Informing safety data sheets (SDS), workplace risk assessments, and emergency response plans with validated inhalation toxicity values.
• Supporting classification for transport and regulatory labeling (links to GHS categories and UN transport guidance are discussed).
• Allowing gas suppliers and end users to calculate mixture toxicity and avoid unnecessary animal testing by using component data.

Who should use this standard

• Cylinder manufacturers and valve designers
• Industrial gas producers and distributors
• Safety officers, occupational hygienists, and process engineers
• Regulatory and transport compliance professionals
• Emergency responders and hazard communication specialists

Related standards and references

• ISO 5145 (valve outlet dimensions)
• ISO 14456 (criteria for compatible gas groups)
• OECD TG 403 (inhalation test guidance referenced for new data)
• GHS and UN Transport Recommendations (classification and time‑adjustment considerations)

Keywords: ISO 10298:2018, gas cylinders, LC50, inhalation toxicity, cylinder valve outlets, gas mixtures, toxicity classification, valve selection, GHS, gas safety.