Understanding the API 598 Valve Testing Standard: A Guide for Engineers and Buyers
In the world of industrial valves—whether used in oil & gas, chemical, power generation, or water treatment—quality assurance is non-negotiable. One key international standard ensuring valve reliability is API 598. If you’re involved in specifying, purchasing, or manufacturing valves, understanding API 598 is essential.
📘 What Is API 598?
API 598 is the American Petroleum Institute’s standard for valve inspection and testing, covering leakage, pressure integrity, and shell testing for a variety of valve types including:
- Gate valves
- Globe valves
- Check valves
- Ball valves (where applicable)
It outlines procedures and acceptance criteria to confirm that valves meet minimum safety and reliability standards before being shipped to customers.
🧪 What Tests Are Required Under API 598?
API 598 specifies two major types of tests:
1. Shell Test (Hydrostatic)
- Purpose: Verifies the strength and structural integrity of the valve body and bonnet.
- How: Water (or compatible liquid) is used to apply pressure to the valve body with the valve in partially open position.
- Pressure: Typically 1.5x the rated pressure.
2. Seat Test (Leakage Test)
- Purpose: Ensures the valve properly seals when closed.
- How: Fluid is applied to either side of the closed valve to test for seat leakage.
- Pressure: Typically 1.1x the rated pressure.
3. Backseat Test (only for valves with a backseat)
- Purpose: Tests sealing capability between stem and bonnet when backseat is engaged.
- How: Internal pressure is applied with the stem in backseated position.
- Pressure: Typically 1.1x the rated pressure.
📌 Valve Types and Applicability
|
Valve Type |
Shell Test |
Seat Test |
Backseat Test |
|
Gate Valve |
✅ |
✅ |
✅ |
|
Globe Valve |
✅ |
✅ |
✅ |
|
Check Valve |
✅ |
✅ |
❌ |
|
Ball Valve |
✅ |
✅ |
❌ |
📌 Duration of Required Test Pressure
|
Valve Size (NPS) |
Minimum Test Duration(Seconds) |
||||
|
Shell |
Backseat |
Closure |
|||
|
Check Valves |
Other Valves |
All Valves with Backseat Feature |
Check Valves |
Other Valves |
|
|
≤ 2 |
60 |
15 |
15 |
60 |
15 |
|
2 1/2 - 6 |
60 |
60 |
60 |
60 |
60 |
|
8 - 12 |
60 |
120 |
60 |
60 |
120 |
|
≥ 14 |
120 |
300 |
60 |
120 |
300 |
Why API 598 Compliance Matters
✅ Safety: Prevents catastrophic failures in high-pressure systems.
✅ Quality Assurance: Ensures leak-tight sealing performance.
✅ Procurement Confidence: Verifiable standard helps specifiers and buyers make informed decisions.
✅ Interoperability: Accepted globally, simplifies cross-border sourcing.
🏭 At Anson Flow, API 598 Comes Standard
At Anson Flow, we follow strict API 598 protocols across our OEM and private-label valve lines. Whether you're sourcing:
- 1-PC / 2-PC / 3-PC ball valves
- Gate, globe, or check valves
- Actuated valve packages
📩 Need Support?
If you're evaluating valve suppliers or want guidance on API 598-compliant components, contact us or email sales@ansonflow.com — our technical team is ready to help.