Engineer-specified plastic tanks for caustic soda (sodium hydroxide, NaOH) storage and dosing service. Industrial Plastics fabricates HDPE and PP-H tanks for caustic across the concentration range and across ambient and elevated-temperature service.
Material selection for caustic soda
Caustic soda is a friendlier chemistry than sulfuric for plastic tanks — HDPE and PP both handle it well across the typical bulk concentration range. The selection criterion is temperature, not concentration.
- HDPE (PE100) — excellent service for ambient-temperature caustic across 0-50%. The default for bulk caustic storage and dosing in water-treatment service.
- Polypropylene (PP-H) — preferred for hot caustic service. Continuous-service envelope to ~80°C, short-term to ~100°C. Standard choice for clean-in-place (CIP) hot caustic tanks in dairy, beverage and food processing, and for hot caustic dosing into pulp & paper service.
PVDF is generally not necessary for caustic — HDPE and PP handle the chemistry across nearly all real-world service conditions. We will recommend PVDF only when the broader process forces it, not because the caustic itself requires it.
Common configurations
- Bulk storage — 5,000 to 50,000 L+ in HDPE. Tanker top-fill with manway, heated jacket where the service requires (50% caustic crystallises below ~12°C), bottom drain, level instrumentation.
- Day tanks & dosing — 200 to 5,000 L. pH-adjustment dosing for water and wastewater treatment, with calibrated platforms for diaphragm and peristaltic pumps.
- Hot caustic CIP — PP-H tanks for hot-caustic clean-in-place service in food and beverage. Insulated where energy efficiency matters.
- Bunded & vented — primary tank inside HDPE bund sized to AS 1940 / AS/NZS 4766 minimum. Vent sizing per maximum fill rate.
Standards and compliance
- AS/NZS 4766 — Polyethylene storage tanks for water and chemicals.
- AS 1940 — Bunding, venting and overflow.
- FSANZ Standard 1.4.3 — Food-contact applications, where the caustic service is a CIP for food-grade plant.
- DVS 2205 (tank design) and DVS 2207 (welding) — welder qualification across HDPE butt welding (DVS 2207-1). More on DVS 2207.
- ISO 9001:2015 — quality management system certified by SGS.
How we work
Send the SDS, the concentration, the operating temperature (ambient vs hot CIP makes the material call), the fill cycle and the service life. We confirm material selection (HDPE for ambient, PP-H for hot service), wall thickness per AS/NZS 4766, and bunding/venting requirements before fabrication starts. DVS 2207 welders, retained test coupons, documented audit trail.
Talk to a fabricator
Trusted by Veolia, Aquatec Maxcon, Goodman Fielder, Schweppes, Warrnambool Cheese & Butter and Origin Energy across water-treatment, food and energy service. Back to Chemical Storage Tanks. Send drawings, P&IDs or an SDS via the contact form — or call 1300 465 888, Mon–Fri 8am–4pm AEST.
Considering a rotomoulded alternative? Read rotomoulded vs fabricated for caustic soda storage — our full engineer-grade comparison.
