i'm not up on 650 requirements, but the cal blocks for performing ut on ss can be expensive.
Appendix S contains Stainless Steel Storage Tank requirements.
UT can be substituded for RT however there are restrictions and requirements contained in appendix U. Here is some of the text from the "Technique" section.
U.3 Technique
U.3.1
The ultrasonic examination volume shall include the
weld metal, plus the lesser of 25mm (1 in.) or t
of adjoining base metal on each side of the weld unless otherwise agreed
upon by the purchaser and the manufacturer.
U.3.2
Ultrasonic examination for the detection of flaws
shall be performed using automated, computer-based data
acquisition except that scanning of adjacent base metal for
flaws that can interfere with the examination may be performed
manually. Ultrasonic examination for sizing of flaws
shall be performed as described in U.6.3.1
Is this new construction, re-construction or repair?
BABRT's
New construction at an ethanol plant.
API 650 Appendix S does not give you the option to UT in lieu of RT. Section S.4.14 gives the requirements of weld inspection on SS tanks Table S-4 determines the joint efficiencies based on radiography.
I am wondering why you would want to UT vs RT? Is this a cost issue?
The tank engineer may be able to do this, with the owners approval, but the tank would not meet the requirements of Appendix S.
BABRT's
It's always a cost issue isn't it!
It was kind of a two part question as there are C.S. and S.S. tanks.
As a company we do not perform field radiography but do provide field UT.
My bigger question is whether I can bid on an API 650 tank and bypass the RT.
If I bid the project and sub out the RT I probably won't be competitive.
API 650 Appendix U allows UT in lieu of Radiography. However it can only be used on plates thicker than 10mm(3/8 inch) so smaller tanks or thinner courses of a larger tank could not be inspected by UT. Most tank erection companies use RT because it is cost effective. 100% of the tank is not inspected only spots. So if you are bidding say a 100 foot tank built to SG 1.0 you would only be able to use UT on the tub as the next course would be 3/8 and the next 2 1/4 inch.
If you are doing and bidding tanks you need the latest edition of API 650 and they are changing it every year.
BABRT's
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