Overview
ISO 21843:2023 specifies a laboratory test method to determine the resistance of fire protection materials and systems on pressure vessels when exposed to standard hydrocarbon pool fires (unconfined pool fires fueled by LPG and petroleum distillates). The standard produces test data that permit classification based on the duration for which the vessel performance satisfies specified criteria. It does not cover vessel design or vessels cooled by water deluge or water monitors.
Key technical topics and requirements
- Test principle and equipment: Defines burner arrangement, fuel supply, test fluids and the test building required to reproduce representative hydrocarbon pool-fire exposure.
- Calibration tests: Procedures to confirm that the burner arrangement and test setup meet the standard’s exposure conditions prior to customer tests.
- Instrumentation: Requirements for thermocouples, directional flame thermometers (DFTs), pressure transducers and other sensors to measure wall temperature, radiation-convection balance and internal pressure.
- Test specimen construction: Guidance for preparing pressure vessel specimens and for affixing thermocouples (see normative Annex C).
- Performance criteria and classification: Criteria based on substrate temperature rise, coatings/spray-applied materials behavior, and pass/fail duration. Classification options include temperature-rise-based and duration-before-failure approaches (Clauses 17 and 19; Annex E).
- Data quality and analysis: Addresses repeatability, reproducibility, uncertainty of measurement and reporting requirements.
- Practical test controls: Includes rules for test termination, handling failures of sensors, and environmental tolerance limits.
- Informative annexes: example piping and instrumentation diagrams, DFT descriptions, radiation-convection balance guidance and additional classification procedures.
Practical applications and who uses it
ISO 21843:2023 is intended for:
- Fire test laboratories conducting hydrocarbon pool-fire resistance tests on pressure vessels and fire protection systems.
- Manufacturers of fire protection materials and thermal insulation systems seeking validated performance data for product development and certification.
- Oil & gas, petrochemical and LPG facility owners/operators who need evidence of fire protection performance for pressure vessels, storage spheres, and tanks.
- Regulatory bodies and certification agencies that require standardized test evidence for safety approvals and procurement specifications.
- Fire safety engineers and consultants specifying protection schemes, selecting materials or using test-based classifications for risk assessments.
Related standards and guidance (context)
- ISO 21843 is part of ISO/TC 92 work on fire safety (fire containment). It complements laboratory fire test standards and industry practices for hydrocarbon fire exposure, instrumentation and classification procedures referenced in its annexes.
Keywords: ISO 21843:2023, hydrocarbon pool fires, fire resistance test, pressure vessels, fire protection systems, directional flame thermometer, calibration test, classification.