ISO 18796-2:2025

Overview

ISO 18796-2:2025 - Internal coating of carbon steel process vessels, Part 2: Requirements and guidance for the selection of coating systems - provides criteria and minimum requirements for selecting internal coatings (linings) for pressurized service within process vessels in the oil and gas (including lower carbon energy) sectors. The standard covers coatings applied directly to carbon steel during new construction, defines the design information needed for selection, and identifies the types of supporting testing and evidence required to demonstrate coating suitability. It explicitly excludes metallic coatings and weld overlay materials.

Key topics and technical requirements

The standard emphasizes a structured, risk-based approach to coating selection and includes guidance on:

• Design inputs for coating selection: required operating conditions and service data that influence selection decisions.
• Environmental and process factors: operating temperature and pressure, decompression rates, gas and liquid composition, solids content and flow, temperature gradients, external temperatures and insulation effects.
• Substrate and post-assembly considerations: substrate material, post-coating assembly and expected service life.
• Coating product information and QA: required product data, packaging, labelling, quality assurance and handling of confidential information.
• Coating identification and verification: fingerprint checks and routine batch checks to confirm product conformity.
• Testing strategy: recommended application testing (to validate coating application) and performance testing (qualification and exposure testing), including panel preparation, surface preparation, dry film thickness, adhesion, porosity detection, conditioning/curing, and assessment methods.
• Supporting documentation: preparation of a coating material selection report (MSR) and standardized test reports.
• Normative and informative annexes: pre‑qualification decision tree, standard liquid/gas compositions for testing, rapid decompression and steam exposure test procedures, and sample reports.

Practical applications and users

ISO 18796-2:2025 is intended for practical use where internal coatings are required to protect carbon steel process vessels in pressurized service. Typical users include:

• Oil and gas companies and asset owners specifying coatings for new vessels
• Engineering, procurement and construction (EPC) contractors and plant designers
• Materials and corrosion engineers specifying lining systems
• Coating manufacturers developing products and preparing qualification data
• Inspection, testing and quality assurance teams evaluating coating conformity

Use cases include selecting coatings for receivers, separators, scrubbers and other pressurized process vessels handling hydrocarbons, CO2-rich streams, water and chemical service streams in conventional and lower-carbon energy projects.

Related standards

• ISO 18796 series (other parts)
• Standards and test methods referenced within ISO 18796-2 for qualification, exposure and performance testing (see Clause 2 and annexes for referenced documents).

Keywords: internal coating, carbon steel process vessels, oil and gas, coating selection, linings, pre-qualification testing, performance testing, coating material selection report (MSR).