What is API 650 Tank?
Tanks which are designed following rules and guidelines of API 650 are API 650 tanks. API 650 is the governing code for Welded tanks for Oil storage normally operating in the atmospheric pressure range. The code API 650 provides guidelines for design, fabrication, material, erection, and inspection of welded vertical and cylindrical storage tanks. Such Tanks must be above ground with a closed or open top.
- MIG/MAG :: Gas Metal Arc Welding Process
- Storage Tank :: Inspection and Test Plan [ITP]
- Storage Tank Inspection API 650
What is API 620 Tank?
API 620 covers the design and construction of field assembled large storage tanks operating in the low-pressure zone. Normally, API 620 tanks have more design pressure as compared to API 650 tanks.
In this article, we will study the major differences that these two types of tanks possess i.e API 650 vs API 620
Similarities between API 650 and API 620 Tanks
- Both tanks are used for storage purposes.
- Both API 620 & API 650 Tanks can be constructed from carbon steel, austenitic stainless steel, and nickel alloys (low temperature only).
- A Welding Certification is stipulated by the American Society of Mechanical Engineers (ASME), Section 10 for both the tanks.
- For both tanks, Non Destructive inspection is required but a third party inspection is not required.
Differences between API 650 and API 620 Tanks: API 650 vs API 620
The major differences between API 650 and API 620 tanks are produced below in a tabular format.
| S.No. | Parameter | API 650 Tanks | API 620 Tanks |
|---|---|---|---|
| 1 | Description | Welded Steel Tanks for Oil Storage | Design and Construction of Large, Low-Pressure Storage Tanks |
| 2 | Configuration | Ground-Supported Bottom, Open or Closed Roof | Any configuration that has a single centered, vertical axis of revolution |
| 3 | Configuration | Entire tank bottom has to be uniformly supported | Such tanks must have a single vertical axis of revolution |
| 4 | Shop/Field Erected | Shop (Appendix J) or Field Erected | Field Erected |
| 5 | Tank Sizes | Any | tank size larger than 300 ft. |
| 6 | Temperature Range | -40 Deg. F to 500 Deg. F | -325 Deg. F to 250 Deg. F |
| 7 | Maximum Pressure | 2.5 psig (pounds per square inch gage) or 17.2 Kpa | 15 psig |
| 8 | Materials | Carbon Steel, Austenitic Stainless Steel, Duplex Stainless Steel, Aluminum | Carbon Steel, Austenitic Stainless Steel, Nickel Alloys (Low Temp only) |
| 9 | Uses/Industries | Oil, Gas, Chemical, Water, and Bio-Fuel storage. Maximum of the most common welded steel tanks used in industry are designed following API 650. Tanks typically found in Refinery tank farms, Terminals, Pipelines, and other process facilities use these tanks. | Tanks like LNG tanks or Cryogenic tanks which requires high internal pressure are designed as per API 620. |