Title: /
API 650 Hydrostatic Test Exemptions
Date: / 1-11-2010 (revised 7-3-2012)Contact: / Name: / David Clark
Company: / Kinder Morgan
Phone: / 708-990-0553
E-mail: /
Purpose: / Highlights to the Purchaser and Fabricator, factors to consider before making a decision not to hydrotest an API 650 tank following fabrication if water is not available.
Source: / Started as an e-mail from Bhana Mistry relating to questions about hydrostatic test exemptions in API 650 and how they are applied or interpreted.
Revision: / 1
Impact: / This change, highlights to the Purchaser and Fabricator, the issue of not conducting a hydrotest if water is not available and the conditions to consider prior to making that decision.
Background: / Started as an e-mail fromBhana Mistry relating to questions about hydrostatic test exemptions in API 650 and how they are applied or interpreted.
At the spring 2012 meeting, Doug Miller commissioned Dave Clark, Steve Caruthers, John Lieb and Rick Ruff to determine requirements and submit a new draft. First section 7.3.5 was broken down into outline format, then additional requirements were determined.
Current wording: /
Proposal: / 7.3.5 Testing of the Shell
After the entire tank and roof structure is completed, the shell (except for the shell of tanks designed in accordance with Appendix F) shall be strength- tested and the foundation initially loaded by one of the following methods, as specified on the Data Sheet, Line 14:
1.If water is available for testing the shell
1.1.the tank shall be filled with water as follows:
a.fillto the maximum design liquid level, H; or
b.for a tank with a liquid - tight roof, fill to 50 mm (2 in.) above the weld connecting the roof plate or compression bar to the top angle or shell; or
c.fillto a level lower than that specified in Subitem 1 or 27.3.5.1.1.a or 7.3.5.1.1.b when restricted by overflows, an internal floating roof, or other freeboard by agreement between the Purchaser and the Manufacturer, or
d.fillto a level of seawater producing a bottom of shellhoop stress in the first shell course equal to that produced by a full-height fresh water test.
1.2.The tank shall be inspected frequently during the filling operation. , and Any welded joints above the test-water level shall be examined after the test is complete in accordance with Item 2 7.3.5.2 below. ThistestThe tank hydrostatic test shall be conducted before permanent external piping is connected to the tank and before any welds are painted. Attachments to the shell defined in 5.8.1.1, located at least 1 m (3 ft) above the water level, and roof appurtenances may be welded during the filling of the tank. After completion of the hydro-test, only non-structural small attachments may be welded to the tank in accordance with 7.2.1.11.
2.If sufficient water to fill the tank is not available
2.1.the tank may be testedshall be examined by:
a.coatingpainting all of the joints on the inside with a highly penetrating oil, such as automobile spring oil, and carefully examining the outside of the joints for leakage prior to; or
b.applying vacuum to either side of the joints or applying internal air pressure as specified for the roof test in 7.3.7 and carefully visually examining the joints for leakage; or
c.Using any combination of the methods stipulated in 7.3.5.2.1.a or 7.3.5.2.1.b.Subitems 1 and 2.
2.2.Additional requirements shall include all of the following:
a. The Purchasershallhydrostatically test to within 3” ofmaximum design liquid level with product, and subsequently reduce the maximum operating level with respect to thatproduct’s gravity.
b. The design basis for the storage tank shall be the greater of the specific gravity of the product intended for normal operation or 1.0, including tank shell thickness and foundation design considerations.
c. All tank shell weld intersections shall be radiographed, regardless of thickness.
2.3.Upon completion ofthese requirements, the first filling of the tank shall be conducted according to section 7.3.6 as if it were a hydrostatic test, including appropriate personnel and fire safety precautions, in accordance with all provisions of 7.3.5.1.1 and 7.3.5.1.2, except that the tank need not be filled above the maximum operating level.
7.3.6 Hydrostatic Testing Requirements
7.3.6.1 This hydrostatic test of the tank shall be conducted before permanent external piping is connected to the tankexcept for piping that is necessary to fill and empty the tank. Attachments to the shell defined in 5.8.1.1, located at least 1 m (3 ft) above the water level, and roof appurtenances may be welded during the filling of the tank. After completion of the hydro-test, only non-structural small attachments may be welded to the tank in accordance with 7.2.1.11. Any welded joints above the test-water level shall be examined for leakage by one of the following methods:
1. coating all of the joints on the inside with a highly penetrating oil, such as automobile spring oil, and carefully examining the outside of the joints for leakage;
2. applying vacuum to either side of the joints or applying internal air pressure as specified for the roof test in 7.3.7 and carefully examining the joints for leakage; or
3. using any combination of the methods stipulated in Subitems 1 and 2.
Rationale: / In the present language of API 650, 7.3.5 Testing of the Shell (650, Eleventh Edition, June 2007, Addendum 2, November 2009), there are no requirements to evaluate the shell and foundation design, toughness requirements, and NDE requirements when hydrostatic testing is not performed. A poll of the members of the Design and Fabrication Subcommittees was taken regarding this issue. The majority of the respondents were in favor of increasing certain requirements; however a consensus could not be established. During the Fall 2010 Standards meeting in Nashville, the SCAST Fabrication Subgroup agreed to the proposed language addition highlighted in Red Italics. This change highlights the issues deemed important to responding members of the previous poll taken.