Onion Tanks FAQs

A Flexible Onion Tank (also known as a collar tank or collapsible tank) is a self-supporting, frameless fabric tank designed for temporary or semi-permanent liquid storage. It folds flat when empty and forms shape as it fills via a floating collar.

Typical applications include firefighting water storage, dust suppression, mining, agriculture, construction, and emergency response. Suitability depends on correct material selection and site conditions.

We offer standard capacities from 2,000L to 130,000L, with custom sizes available on request.

Yes. All Fleximake Onion Tanks are manufactured in Australia.

Place the tank on a level surface cleared of sharp objects, position the ground sheet, and begin filling. The collar rises as the tank fills.

No permanent foundation is typically required. However, the tank must be installed on stable, level ground suitable for the load.

Yes, once fully drained. Tanks must not be moved when filled or partially filled.

Drain completely via outlet or pump, allow to dry where possible, then fold and store in a clean, dry, shaded area.

Fleximake Onion Tanks are manufactured from heavy-duty industrial fabrics designed for resistance to abrasion, UV exposure, and general wear. However, they must be protected from sharp objects and unsuitable ground conditions.

Typical service life varies depending on usage, environment, UV exposure, and stored liquid:
• RPVC: approx. 5–8+ years (water applications)
• TPU: approx. 8–12+ years (potable water, fuels*)
• ER1000: approx. 5–8+ years (chemical use*)

Actual lifespan may vary significantly depending on operating conditions and maintenance.

Yes, materials are UV-stabilised. For extended life, we recommend protective covers, routine inspection, and proper storage when not in use.

Yes, only when the correct fabric is selected and confirmed compatible with the specific liquid:
• TPU (TPUN): fuels, diesel, oils*
• ER1000 (ER10): selected chemicals*
• RPVC (P14N): certain industrial liquids*

⚠️ Important:
• Not all liquids are compatible with all materials
• Chemical concentration, temperature, and exposure duration affect suitability
• Written confirmation from Fleximake is recommended prior to use

Yes, when manufactured using certified potable-grade materials (e.g. RPVC or TPU compliant with AS/NZS 4020). Proper handling and hygiene procedures are required.

Yes. Storage of fuels and hazardous chemicals may be subject to:
• Local council regulations
• Environmental protection requirements
• Workplace safety laws

It is the user’s responsibility to ensure compliance with all applicable regulations.

Tanks can be cleaned internally using appropriate, non-abrasive methods. Some models include internal access features to assist with inspection and cleaning.

Minor damage may be repairable using approved patch kits. Repairs should be carried out in accordance with Fleximake guidelines. Severe damage may require professional repair or replacement.

An optional top cover can reduce ingress of debris, dust, and wildlife. This is recommended for potable water and long-term storage.

When installed correctly on level, stable ground and filled as intended, the tank is designed to remain stable. Uneven ground, high winds, or improper use may affect stability.

Yes. Tanks can be connected using appropriate fittings and hoses. System design should consider flow rates, pressure, and site conditions.

Please provide:
• Required capacity (Litres)
• Intended application (water, fuel, chemical, etc.)
• Preferred material (or request recommendation)
• Required fittings and accessories

Fleximake Onion Tanks are designed for a wide range of liquid storage applications; however:
• Final suitability depends on correct product selection, installation, and use
• Compatibility with specific fuels or chemicals must be confirmed prior to use
• Users are responsible for ensuring compliance with all relevant regulations and safety requirements