Pressure vessels play a critical role in industrial operations, storing energy or process media under pressure. Because they present high levels of potential risk, strong regulations guide how they must be inspected, maintained and certified — and AS/NZS 3788 is the central framework used across Australia.
This blog explains what AS/NZS 3788 covers, what duty-holders must do to comply and why correct inspection and documentation help prevent catastrophic failures.
What AS/NZS 3788 Covers
AS/NZS 3788 focuses on the in-service inspection of pressure equipment. It applies to:
- Pressure vessels
- Boilers
- Heat exchangers
- Certain piping systems
The standard outlines how equipment must be inspected after commissioning and throughout its operational life. It also defines inspection intervals, types of inspections, hazard levels and record-keeping requirements.
Hazard Levels & Registration Obligations
Each pressure vessel is assigned a hazard level according to AS 4343 (Pressure Equipment—Hazard Levels). Hazards range from A (highest risk) to E (lowest risk), and the level determines:
- Inspection frequency
- Whether the vessel must be registered
- Level of documentation required
Hazard Level A or B:
Requires formal registration and rigorous inspection schedules.
Hazard Level C, D, E:
Lower risks but still require inspection and traceable maintenance history.
Key Obligations Under AS/NZS 3788
1. Establish an Inspection Plan
Each pressure vessel must have an inspection plan covering:
- In-service inspection intervals
- Type of inspection (external, internal, NDT, pressure test)
- Acceptance criteria
- Equipment history
2. Conduct Regular Inspections
Inspections must be carried out by competent personnel with appropriate certification. Depending on the hazard level, these may include:
- Internal visual inspections
- External inspections
- Advanced NDT
- Relief valve testing
- Hydrostatic testing
3. Maintain Documentation
Operators must keep accurate records of:
- Test reports
- Inspection findings
- Repairs and modifications
- PSV certification
- Risk assessments
Traceability is crucial for demonstrating compliance.
4. Ensure Safe Operation & Maintenance
Duty-holders must implement procedures for:
- Safe shutdowns
- PSV testing
- Managing corrosion and degradation
- Maintaining compliance with operating limits
Why Compliance Matters
Pressure vessel failures can lead to severe injury, equipment damage or production loss. AS/NZS 3788 ensures:
- Equipment operates within safe limits
- Early detection of deterioration
- Reduced risk of catastrophic failures
- Compliance with workplace safety laws