GRP tanks and vessels for use above ground - Delivery, installation and maintenance
1Key Takeaways
This document specifies requirements for the specification and acceptance conditions of raw materials for GRP tanks and containers for above-ground use, whether or not lined, for the storage or processing of fluids, factory-made or site-built, non-pressurized or pressurized. Together with the process principles for the…
2Expert Interpretation
In-depth interpretation of BS EN 13121-1:2021 on the specification requirements for raw materials of above-ground GRP tanks, covering the performance indicators, test methods and compliance document requirements of key materials such as thermosetting resins, reinforcement materials, thermoplastic linings, etc. The standard replaces the 2003 version, complies with the requirements of the EU 2014/68/EU Pressure Equipment Directive, and is suitable for the assessment of Class III/IV materials for pressure vessels.
Analysis of the core content of the standard
Scope of application
This standard applies to factory-made or on-site constructed GRP tanks and containers for above-ground use, including:
- Non-pressure and pressure equipment (working pressure ≤ 0.5bar)
- Structures with/without thermoplastic lining
- Chemical industry equipment for storing or processing fluids
Comparison of material technical specifications
| Material category | Key performance indicators | Test standards | Update points (vs 2003 version) |
|---|---|---|---|
| Thermosetting resin | Viscosity, gel time, HDT temperature, tensile strength | EN ISO 2555/2535 | New classification of vinyl ester polyurethane resin (VEU) |
| Reinforcement material | Mass per unit area, combustible content | ISO 3374/1887 | Specify the use specifications of multi-axial fabrics |
| Thermoplastic lining | Melt index, Vicat softening temperature | EN ISO 1133/306 | New requirements for ETFE materials |
Key points for compliance implementation
Material compliance documents
Manufacturers need to provide the following certification documents (retained for 5 years):
- Resin: EN 10204 3.1 type inspection certificate, including performance data before and after curing
- Liner material: Peel strength test report (≥20N/mm)
- Reinforcement material: Combustible content test report (ISO 1887)
Technology evolution analysis
The main technological breakthroughs of this standard are reflected in:
- The resin classification system adds chemical resistance requirements for halogenated bisphenol A type vinyl ester resins
- Thermomechanical analysis (TMA) is introduced to determine the linear thermal expansion coefficient of the lining material
- The application specifications of conductive fillers (graphite/carbon black) in the antistatic layer are clarified
Application case: Material selection for chemical storage tanks
A hydrochloric acid storage tank adopts a combination of VE7A resin (classification in Table 2) + PP-H lining, which passes:
- Resin HDT temperature ≥ 110℃ (EN ISO 75-2)
- Lining melt index 0.8g/10min (EN ISO 1133)
- Interlaminar shear strength test (EN 13121-3 Appendix D)
Meets the pressure-bearing requirements of Category IV of the PED Directive.
Recommendations for the implementation of the standard
- Raw material suppliers should establish a quality control system that complies with ISO 9001
- Manufacturers need to keep complete material traceability records (batch number + expiration date)
- Type III/IV pressure vessels need to pass material evaluation by a notified body
- When it comes to food contact applications, it must comply with EC Regulation 1935/2004