| Dear Mr.Dhanasekaran,
As queried belowAPI 650 Para 8.1.2.2 and 8.1.2.3 covers the complete requirements of radiography for construction of storage tanks.
i.e.,If you did as per the sec.8.1.2.2 and 8.1.2.3,there itself it is mentioned(Marked Red Below),that you have to take one spot radiography in first 3m of welded joint of each welder or welding operator.So if you are using 20 welders,you needs to take 20 spots ,then needs to satisfy the other requirements based on type/thickness of joints in additional.
Therefore if you satisfy the API 650 para 8.1.2.2 and 8.1.2.3,there is no other requirements of radiography in related with storage tank construction works.
Regards,
Thiru.
On Fri, 1/4/11, DHANASEKARAN SUBRAMANIAM <subramaniamdhanasekaran7@gmail.com> wrote:
From: DHANASEKARAN SUBRAMANIAM <subramaniamdhanasekaran7@gmail.com>
Subject: [MW:10555] Tank Radiography
To: materials-welding@googlegroups.com
Date: Friday, 1 April, 2011, 1:08 PM
Dear all, We are constructing tanks as per API-650; in which the radiography requirements are given in Sec.8 (Spot Radiography), We did radiography as mentioned in 8.1.2.2 & 8.1.2.3 (KINDLY REFER BELOW) Kindly clarify the following doubts; 1. Consider a particular tank is welded with 20 welders, we fulfilled the requirements as per 8.1.2.2 & 8.1.2.3 , even though the fulfillments are met, is it required to take radiography spots on each welders? 2. Is it required to take radiography for an individual welder based based on the length welded? If it so what is the requirements & references. API-650 8.1.2.2 The following requirements apply to vertical joints: a. For butt-welded joints in which the thinner shell plate is less than or equal to 10 mm ( 3/8 in.) thick, one spot radiograph shall be taken in the first 3 m (10 ft) of completed vertical joint of each type and thickness welded by each welder or welding operator. The spot radiographs taken in the vertical joints of the lowest course may be used to meet the requirements of Note 3 in Figure 8-1 for individual joints. Thereafter, without regard to the number of welders or welding operators, one additional spot radiograph shall be taken in each additional 30 m (100 ft) (approximately) and any remaining major fraction of vertical joint of the same type and thickness. At least 25% of the selected spots shall be at junctions of vertical and horizontal joints, with a minimum of two such intersections per tank. In addition to the foregoing requirements, one random spot radiograph shall be taken in each vertical joint in the lowest course (see the top panel of Figure 8-1). b. For butt-welded joints in which the thinner shell plate is greater than 10 mm ( 3/8 in.) but less than or equal to 25 mm (1 in.) in thickness, spot radiographs shall be taken according to Item a. In addition, all junctions of vertical and horizontal joints in plates in this thickness range shall be radiographed; each film shall clearly show not less than 75 mm (3 in.) of vertical weld and 50 mm (2 in.) of weld length on each side of the vertical intersection. In the lowest course, two spot radiographs shall be taken in each vertical joint: one of the radiographs shall be as close to the bottom as is practicable, and the other shall be taken at random (see the center panel of Figure 8-1). c. Vertical joints in which the shell plates are greater than 25 mm (1 in.) thick shall be fully radiographed. All junctions of vertical and horizontal joints in this thickness range shall be radiographed; each film shall clearly show not less than 75 mm (3 in.) of vertical weld and 50 mm (2 in.) of weld length on each side of the vertical intersection (see the bottom panel of Figure 8-1). d. The butt-weld around the periphery of an insert plate that extends less than the adjacent shell course height and that contains shell openings (i.e. nozzle, manway, flush-type cleanout, flush type shell-connection) and their reinforcing elements shall be completely radiographed. e. The butt-weld around the periphery of an insert plate which extends to match the adjacent shell course height shall have the vertical and the horizontal butt joints and the intersections of vertical and horizontal weld joints radiographed using the same rules that apply to the weld joints in adjacent shell plates in the same shell course. 8.1.2.3 One spot radiograph shall be taken in the first 3 m (10 ft) of completed horizontal butt joint of the same type and thickness (based on the thickness of the thinner plate at the joint) without regard to the number of welders or welding operators. Thereafter, one radiograph shall be taken in each additional 60 m (200 ft) (approximately) and any remaining major fraction of horizontal joint of the same type and thickness. These radiographs are in addition to the radiographs of junctions of vertical joints required by Item c of 8.1.2.2 (see Figure 8-1).
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WITH REGARDS,
DHANASEKARAN .S , Mob.no: +96893220429.
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