BS EN 14620-5-2025 PDF

Full title and description

STB BS EN 14620-5:2025 — Design and manufacture of site built, vertical, cylindrical, flat‑bottomed tank systems for the storage of refrigerated, liquefied gases with operating temperatures between 0 °C and −196 °C — Part 5: Testing, drying, purging and cool‑down. This document sets out requirements and recommended procedures for the post‑construction verification, commissioning (drying, inerting/purging and cool‑down) and safe decommissioning of large site‑built refrigerated liquefied gas (RLG) storage tanks, including specific provisions for double‑wall and membrane tank constructions.

Abstract

EN 14620‑5:2025 defines the tests, inspection activities and operational procedures to be carried out after construction and before the first service of vertical, site‑built, flat‑bottomed cryogenic tanks and during decommissioning or major maintenance. Key topics include hydrostatic and pneumatic integrity tests, water quality for hydrotests, settlement monitoring during full/partial filling, requirements and limits for drying and inerting (purging) with both inert and product gases, controlled cool‑down procedures and monitoring, special provisions for double‑wall and membrane tanks, and guidance for end‑of‑life safe gas freeing and decommissioning.

General information

• Status: Published (CEN definitive text adopted and available via national bodies).
• Publication date: 30 September 2025 (CEN definitive text; national adoptions/publication dates may vary between Sep–Dec 2025).
• Publisher: British Standards Institution (BSI) as BS adoption of CEN EN 14620‑5:2025 (text produced by CEN/TC 265 and published through national members).
• ICS / categories: 23.020.10 — Stationary containers and tanks.
• Edition / version: 2025 edition (revision of the previous EN 14620‑5:2006 series).
• Number of pages: 30 (approx.; varies slightly between national publications/formats).

Scope

This part of EN 14620 applies to site‑built, vertical, cylindrical, flat‑bottomed tank systems used to store refrigerated liquefied gases with operating temperatures between 0 °C and −196 °C. It specifies requirements and procedures to verify the mechanical integrity and service readiness of tanks after construction and before commissioning, and to ensure safe decommissioning or gas‑freeing at major maintenance or end‑of‑life. The standard covers full and partial hydrostatic tests, positive and negative pressure tests, drying and inerting/purging with both inert and product gases (including recommended oxygen concentration limits), controlled cool‑down procedures and temperature monitoring, testing provisions for double‑wall and membrane tanks, and guidance on foundation settlement monitoring during testing.

Key topics and requirements

• Hydrostatic testing procedures: full‑height and reduced/partial‑height water tests to verify structural integrity and to assess foundation performance (including water quality requirements to limit corrosion).
• Pneumatic testing: positive and negative pressure test procedures to confirm leak tightness and valve performance; special measures for double‑wall and membrane systems.
• Drying and purging (inerting): methods and acceptance criteria for drying and inerting before cool‑down or commissioning, including required oxygen concentration limits for different RLGs and recommended purge gases and flow strategies.
• Cool‑down procedures and monitoring: staged cool‑down methods to minimize thermal stresses, recommended temperature measurement and monitoring during cool‑down, and informative guidance for instrumentation and rates.
• Settlement and foundation monitoring: procedures for settlement measurement during hydrotests and start‑up to confirm foundation behaviour and to establish baseline data for ongoing monitoring.
• Double‑wall and membrane tanks: specific test methods and acceptance criteria for inner/outer containment and for membrane integrity (including informative annex guidance for global testing of membrane systems).
• Water quality and corrosion control: specifications and recommendations for fresh and seawater used in hydrostatic tests to reduce corrosion risk to tanks and accessories.
• Commissioning, documentation and records: required test records, NDE reports, instrument calibration and operator responsibilities during commissioning activities.
• Decommissioning and gas‑freeing: safe procedures for draining, gas freeing, inspection and final decommissioning steps to protect personnel, environment and adjacent assets.

Typical use and users

This standard is used by engineers, tank designers, tank manufacturers, on‑site construction and erection contractors, commissioning teams, inspection and certification bodies, terminal operators (LNG, LPG, ammonia and industrial gases), and regulatory authorities responsible for large above‑ground refrigerated storage tanks. It is typically applied during the factory/site acceptance, pre‑commissioning and commissioning phases and when planning major maintenance or decommissioning activities.

Related standards

EN 14620‑5:2025 is part of the EN 14620 series. Relevant related documents include EN 14620‑1 (General), EN 14620‑2 (Metallic components), EN 14620‑3 (Secondary containment / foundations and related rules), EN 14620‑4 (Insulation components) and earlier EN 14620 editions. It is also used alongside other cryogenic and pressure equipment standards (for example EN 13445 for higher‑pressure vessels and ISO/EN standards on cryogenic pressure vessels and relief sizing) and national/adopted versions (BS EN, DIN EN, UNE EN, etc.).

Keywords

EN 14620‑5, refrigerated liquefied gas (RLG), cryogenic tank, hydrostatic test, pneumatic test, drying, purging, inerting, cool‑down, commissioning, decommissioning, membrane tank, double‑wall tank, settlement monitoring, water quality, tank commissioning procedures.

FAQ

Q: What is this standard?

A: EN 14620‑5:2025 is the part of the EN 14620 family that specifies tests, drying, purging and cool‑down procedures for site‑built vertical cylindrical flat‑bottomed tanks used to store refrigerated liquefied gases (0 °C to −196 °C).

Q: What does it cover?

A: It covers post‑construction verification and commissioning activities (hydrostatic and pneumatic testing, water quality for tests, drying and purging/inerting procedures, controlled cool‑down and temperature monitoring), special provisions for double‑wall and membrane tanks, settlement monitoring during testing, and guidance for safe decommissioning and gas freeing.

Q: Who typically uses it?

A: Tank designers and manufacturers, site erection and commissioning teams, terminal and plant operators (LNG, LPG, ammonia, industrial gases), inspection and certification bodies, and regulators involved in the approval and safe operation of large cryogenic storage tanks.

Q: Is it current or superseded?

A: The 2025 edition is the current revision of Part 5 (superseding the earlier edition published in 2006). National adoptions (BS EN, DIN EN, UNE EN, etc.) reflect the CEN text and may show slightly different publication dates.

Q: Is it part of a series?

A: Yes — EN 14620 is a multi‑part series covering the design, materials, insulation and testing/commissioning of site‑built refrigerated liquefied gas tanks. Relevant parts include EN 14620‑1 (General), EN 14620‑2 (Metallic components), EN 14620‑3 (foundations/secondary containment) and EN 14620‑4 (Insulation components).

Q: What are the key keywords?

A: Refrigerated liquefied gases (RLG), cryogenic tanks, commissioning, hydrostatic test, purging/inerting, cool‑down, membrane tanks, double‑wall tanks, settlement monitoring, decommissioning.