API598 is a valve inspection and testing standard developed by the American Petroleum Institute, with its seventh edition published in October 1996. This standard specifies the pressure testing methods and acceptance criteria for various industrial valves, and is an important basis for valve quality control in industries such as petroleum and chemical. The standard is mainly applicable to common valve types such as gate valves, globe valves, plug valves, ball valves, check valves, and butterfly valves, and also allows for application to other special valves after consultation between users and manufacturers.
Get a Technical Quote for API 598 Tested Ball, Gate, and Globe Valves in 24 Hours.
API 598 Minimum Test Durations
| Valve Size (NPS) | Shell Test (Seconds) | Backseat Test (Seconds) | Closure Test (Seconds) |
|
≤≤ 2" |
15 | 15 | 15 |
| 2 ½" to 6" | 60 | 60 | 60 |
| 8" to 12" | 120 | 120 | 120 |
|
≥≥ 14" |
300 | 300 | 300 |
Required Tests for API 598 Valves
| Valve Type | Shell Test | Backseat Test | Low-Pressure Closure | High-Pressure Closure |
| Gate Valve | Mandatory | Mandatory | Mandatory | Optional (1) |
| Globe Valve | Mandatory | Mandatory | Mandatory | Optional (1) |
| Check Valve | Mandatory | N/A | Optional | Mandatory |
| Ball Valve | Mandatory | N/A | Mandatory | Optional (1) |
| Butterfly Valve | Mandatory | N/A | Mandatory | Optional (1) |
| Plug Valve | Mandatory | N/A | Mandatory | Optional (1) |
Pressure Test Requirements
| Test Item | Test Medium | Test Pressure |
| Shell Test | Liquid (Water) |
≥≥ 1.5×× CWP |
| Backseat Test | Liquid (Water) |
≥≥ 1.1×× CWP |
| High-Pressure Closure | Liquid (Water) |
≥≥ 1.1×× CWP |
| Low-Pressure Closure | Gas (Air / Nitrogen) | 60 psi ~ 100 psi (4~7 bar) |
Maximum Allowable Leakage Rates
Liquid Test (Maximum Drops per minute)
| Valve Size (NPS) | Soft Seat | Metal Seat (Gate/Globe/Ball) | Metal Seat (Check Valve) |
|
≤≤ 2" |
0 | 0 (1) | 0 (1) |
| 2 ½" ~ 6" | 0 | 12 | 3 per inch of NPS |
| 8" ~ 12" | 0 | 20 | 3 per inch of NPS |
|
≥≥ 14" |
0 | 2 per inch of NPS | 3 per inch of NPS |
Gas Test (Maximum Bubbles per minute)
| Valve Size (NPS) | Soft Seat | Metal Seat (Gate/Globe/Ball) | Metal Seat (Check Valve) |
|
≤≤ 2" |
0 | 0 (1) | 0 (1) |
| 2 ½" ~ 6" | 0 | 24 | 6 per inch of NPS |
| 8" ~ 12" | 0 | 40 | 6 per inch of NPS |
|
≥≥ 14" |
0 | 4 per inch of NPS | 6 per inch of NPS |
API 598 VS API 6D Core Scope and Application
| Features | API 598 (General Inspection Standard) | API 6D (Pipeline Specific Specification) |
| Full Name | Valve Inspection and Testing | Specification for Pipeline and Piping Valves |
| Primary Application | Refining, Chemical Plants, General Industry (Process Piping) | Long-Distance Pipelines, Midstream Oil & Gas |
| Coverage Scope | Limited to Inspection and Pressure Testing | Covers Design, Manufacturing, Assembly, Inspection, and Testing |
| Common Valve Types | Gate, Globe, Ball, Check, Plug, Butterfly | Ball (Trunnion), Slab Gate, Check, Plug |
| Design Requirements | None (usually follows ASME B16.34) | Explicit requirements (e.g., Full Bore, Drain, Cavity Relief) |
API 598 VS API 6D Testing Items and Pressures
| Test Item | API 598 (Process) | API 6D (Pipeline) |
| Shell Test | 1.5
×× Pressure Rating (CWP) |
1.5
×× Pressure Rating (CWP) |
| Low-Pressure Closure | Mandatory (60-100 psi Air) | Mandatory (60-100 psi Air) |
| High-Pressure Closure | Optional for Metal Seats; Mandatory for Soft Seats | Mandatory for ALL Valves (1.1
×× CWP) |
| Backseat Test | Mandatory for Gate/Globe Valves | Mandatory for Gate Valves |
| DBB / DIB Testing | Not Included | Optional/Mandatory for Pipeline Ball Valves (Functional Testing) |
GNEE API Valve factroy
User Intent: By answering "What it stands for" early and then providing "How to buy" advice, this content fulfills both informational and commercial search intent.
FAQ
What is the difference between API 598 and API 607?
API 598 – Covers testing and inspection for gate, globe, ball, and check valves. It defines hydrostatic shell, seat, and backseat tests, specifying maximum allowable leakage rates. API 607 – Focuses on fire testing for soft-seated quarter-turn valves to ensure operation after exposure to flame and heat.
What is the difference between API 598 and API 600?
API 600 covers steel gate valves, API 6D covers pipeline valves, and API 598 covers valve inspection and testing. Product data for API-rated items must include the applicable standard as an attribute to ensure correct specification and procurement.