Storage tanks are high-consequence assets. A single loss of containment can harm people, contaminate soil or groundwater, disrupt operations, and trigger regulatory action.
In Western Australia (WA), duty holders must show both compliances:
- Meeting laws, codes and integrity
- Fitness for service over time
This guide outlines a practical pathway for owners and operators in mining, oil and gas, industrial and chemical, food and beverage, and public assets.
For organisations seeking independent verification or support with inspection and repair scopes, Asset Management Engineers (AME) provide American Petroleum Institute (API)-certified storage tank inspections and integrity services.
WA’s Regulatory Landscape: Who Regulates What
In WA, several regulators define the rules for how tanks are designed, stored, and maintained.
- WorkSafe WA (Department of Mines, Industry Regulation and Safety, DMIRS) oversees workplace safety and dangerous goods storage. If you handle flammable, combustible, toxic, or corrosive liquids, licensing, placarding and operational controls may apply. Guidance is available in the WorkSafe WA note on storage and handling licensing/exemptions.
- Department of Water and Environmental Regulation (DWER) and the Environmental Protection Authority (EPA) manage environmental protection. Where tanks are near bores, waterways, wetlands, or public drinking water sources, siting and containment follow WA guidance on tanks near sensitive water resources. This includes bund capacity, setbacks, and impermeable liners.
- Confined space requirements apply whenever tanks are entered for cleaning, inspection, or repair. WA follows the national Work Health and Safety (WHS) model, which calls for permits, gas testing, rescue planning, and supervision for confined-space entry.
Compliance depends on meeting all three areas: safety, environment, and workplace health.
Integrity Fundamentals: What Fails, Where, and Why
Integrity means the tank, its fittings, and its containment systems perform as designed and intended under normal and upset conditions.
- Primary containment includes the shell, roof, floor, nozzles, manways, and welds.
- Secondary containment covers bunds and liners sized and sealed to capture spills and contaminated stormwater.
- Ancillary systems cover vents, pressure/vacuum valves, overfill and level instruments, earthing, and lightning protection. They also include safe access features such as fixed ladders and platforms.
Common degradation mechanisms
- Corrosion occurs both inside and outside. Internally, water bottoms and sludge promote “under deposit” pitting, especially in the critical zone (the first 100–150 mm above the floor-to-shell weld) and across the annular ring. Externally, rainwater at the chime and corrosion under insulation are common. Controls include coatings, linings, regular dewatering, and cathodic protection where needed.
- Settlement and distortion can stress shell courses and nozzle connections. Plumbness and levelness should be checked routinely by trained and competent persons.
- Operational and thermal effects are intensified in WA’s heat. Daily cycling and pressure/vacuum events, such as blocked vents or rapid filling and emptying, can fatigue shells and roofs.
- Coating and lining breakdowns are caused by UV exposure, chemical attack, or ageing. Blisters and pinholes should be repaired quickly to prevent under-film corrosion.
- Secondary containment failure happens when bund walls crack, drain valves are left open, or liners degrade. Even a small leak can then become a reportable incident.
Western Australian Context
Remote sites, saline conditions, cyclonic rain, and high UV accelerate tank degradation. An integrity plan tailored to these conditions, combined with strict confined-space and hot-work controls, must be in place to avoid incidents and downtime.
Tank Types and Typical Compliance Focus
Above-ground storage tanks
These tanks are easier to access but more exposed to weather and fire. Design and upgrades usually follow the Australian standard for steel tanks or the API standard for large welded tanks. Operations align with the national standard for the storage and handling of flammable and combustible liquids, with bunding requirements for sensitive sites.
Underground storage tanks
These carry higher environmental risk and rely on preventive design and monitoring rather than visual inspection. Compliance is based on the Australian standard for underground petroleum storage systems, which sets requirements for double-wall construction, monitoring, spill containment, leak detection, and inventory control.
Fuel and oil tanks
Fire and explosion hazards drive the need for separation distances, hazardous area zoning, and emergency response planning. These tanks are operated in line with the Australian flammable liquids standard and supported by Safe Work Australia guidance.
Water and benign process tanks
Although the chemical hazard is lower, structural failure and hygiene still must be managed. Large atmospheric water tanks are commonly designed to API specifications and require periodic internal inspection.
Speciality chemical and cryogenic tanks
Compliance depends on material compatibility and ventilation. Australian standards for corrosives and toxics apply, with broader controls outlined in Safe Work’s guidance on storing hazardous chemicals.
Portable and temporary tanks (IBCs, skids, frac tanks)
Even short-term storage must meet dangerous goods and workplace safety requirements. Bunding, separation, labelling, and pre-use inspection all apply.
Standards and Codes: Design, Operation, Inspection
Design and construction
- AS 1692 – The Australian standard for steel tanks storing flammable and combustible liquids.
- API 650 – The American Petroleum Institute (API) standard for large welded above-ground tanks, including floating and fixed roofs.
- AS4897 – The Australian standard for underground petroleum storage systems, covering design, installation, and operation.
Operations (storage and handling)
- AS1940:2017 – The Australian standard for storage and handling of flammable and combustible liquids. It covers site layout, separation distances, hazardous areas, bunding, overfill, and venting.
- The Safe Work Australia guide to the storage of flammable liquids, which explains the requirements in plain English and aligns with the national standard.
- Safe Work Australia’s guidance on storing hazardous chemicals, which covers segregation, labelling, and risk controls for substances below dangerous goods thresholds.
In-service inspection and repair
- API 653 – The API standard for in-service inspection and repair of above-ground tanks, covering external and internal inspection intervals, thickness checks, settlement, and repair criteria.
- AS 3788:2024 – The Australian standard for pressure equipment inspection, which distinguishes between atmospheric tanks and pressure vessels.
- AS 1657 – The Australian standard for fixed ladders, platforms, and walkways, covering access systems and fall protection.
WA Laws and Licensing: What You Must Meet
- The Dangerous Goods Safety Act 2004 (WA), which sets responsibilities and penalties for storage and handling.
- The Dangerous Goods Safety (Storage and Handling) Regulations 2007, covering licensing triggers, risk assessments, placarding, and emergency planning.
- The Work Health and Safety (WHS) General Regulations 2022, which outline requirements for hazardous chemicals, confined spaces, and general risk management.
- Water Quality Protection Note 56, which sets environmental siting and containment controls near sensitive receptors.
When demonstrating compliance, regulators expect to see records such as licences, inspection reports, bund capacity calculations, leak detection data, and confined space permits.
Inspection and Testing: How to Know Your Risk (and Prove Control)
A defensible inspection program blends minimum code requirements with risk-based adjustments.
Techniques to plan for
- External visual checks of coatings, corrosion, leaks, shell plumbness, and settlement.
- Internal visual inspection with confined-space controls, focusing on the annular ring, floor-to-shell welds, and nozzles.
- Ultrasonic thickness mapping of shell courses and floors, with automated scanning where needed.
- Magnetic flux leakage floor scanning to detect sub-surface corrosion and pitting, followed by ultrasonic confirmation.
- Vacuum box testing of floor seams, patches, and welds.
- Magnetic particle or dye penetrant inspection for crack detection on nozzles, manways, and repairs.
- Holiday (spark) testing of linings to locate pinholes before returning tanks to service.
- Leak or tightness testing for underground tanks and critical services.
Inspection intervals
As a baseline for above-ground tanks, external inspection should be carried out at least every five years, and internal inspection about every ten. Data on corrosion history should guide shorter intervals for aggressive service or justify extensions only with strong engineering evidence and monitoring.
Underground tanks demonstrate integrity through design, continuous leak detection, inventory control, and periodic precision testing rather than internal visuals.
Confined-space compliance is mandatory. Entry must follow permit systems, gas testing, and rescue readiness in line with regulations.
Preventive Maintenance: Keep Small Defects Small
Turning inspection findings into scheduled work prevents minor defects from escalating.
- Corrosion control: Maintain external coatings and specify internal linings in aggressive service. Apply and maintain cathodic protection for soil-side floors and buried components. Check rectifier readings and anode life. For mechanisms and mitigations, see the AME guide to corrosion.
- Water bottoms and sludge: Drain water regularly, sample for phase separation, and desludge when required. Monitor for microbial activity, especially in diesel, and apply treatments where needed.
- Secondary containment: Inspect bund walls and liners for cracking. Verify capacity is at least 110% of the largest tank. Keep drains locked, test automated pumps, and clear vegetation and sediment.
- Appurtenances and safety systems: Calibrate alarms, test pressure/vacuum valves, verify earthing and lightning protection, and maintain access and guarding to the relevant standard.
- Change management and repairs: Repairs must follow recognised tank repair standards, using qualified welders and appropriate non-destructive testing. Any service change should be reviewed by engineering.
- Records and scheduling: Track thickness trends, remaining life, inspection due dates, and licence or permit expiries. For guidance on structuring programs and work orders, see AME’s preventive maintenance resources.
Sector Specifics: WA Context
Mining, oil & gas
Large above-ground tanks in remote and harsh conditions need robust design and inspection. Design should follow the API standard for large welded tanks. Inspections and repairs are carried out to the API in-service storage tank standard. Bunds and liners must handle cyclone rainfall. Cathodic protection is required in saline soils.
Industrial, chemical, and food
These sites often store different chemical classes. The Australian standard for flammable and combustible liquids applies. Broader requirements are covered in Safe Work guidance on storing hazardous chemicals. Internal linings and ventilation are critical. More frequent internal inspections are needed where contents are aggressive.
Government and hospitals
Typical tanks include diesel for backup power, pool chemicals, and medical gases. In urban areas, the consequences of failure are greater. Bund integrity and emergency planning are vital. Confined-space and hazardous chemical compliance must be reinforced. Safe Work’s flammable liquids guide and hazardous chemicals portal provide direction.
Implementation Roadmap: Key Steps
1. Establish your baseline
Create a single register of all tanks. Record ID, contents, volume, location, construction code, year, last inspection, bund volume, licence numbers, leak-detection method, and known issues. Map each tank against the relevant standards and WA laws.
2. Close critical gaps first
Fix shortfalls in bund capacity or cracked liners. Address missing overfill or venting controls. Ensure underground tanks have compliant leak detection and inventory control. Resolve any confined-space permit or practice gaps. Temporary measures may be needed until permanent fixes are in place.
3. Plan inspections using risk
Set external and internal inspection dates based on service, age, corrosion history, and consequence. Validate leak detection on underground tanks and schedule precision tests. Prepare confined-space controls, isolation, and cleaning in advance.
4. Execute and remediate
Carry out visual inspections, thickness testing, and floor scans as planned. Focus on the annular ring and other critical zones. Repairs should follow recognised tank repair standards. Retest using vacuum box, holiday testing, or hydrostatic methods where required. Reinstate cathodic protection and verify performance.
5. Institutionalise preventive maintenance
Drain water bottoms, service valves and instrumentation, maintain coatings and linings, and keep bunds in good condition. Configure work orders for annual checks and track thickness and cathodic protection data.
6. Prove compliance
Keep a live audit pack. Include licences, inspection reports with code references, bund calculations, confined-space records, spill drills, and training logs. Each requirement should be supported by dated evidence.
Putting It Into Practice
In Western Australia, compliance and technical integrity must work together. Following recognised Australian and international standards, supported by a risk-based inspection and maintenance program, reduces the chance of leaks and failures while meeting regulator and insurer expectations.
If you need a quick gap review or a full inspection and repair plan, AME can support you through storage tank inspections and non-destructive testing services.