PROCEDURE-FOR-RADIOGRAPHY-TESTING

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LARSEN & TOUBRO LIMITED MSQ(EPCC 1) UP GRADATION PROCEDURE FOR RADIOGRAPHY TESTING

DATE:-03.11.2007 REV.NO.- 0 PROCEDURE NO.LT/MSQ/P/ RT /009

CONTENTS

1. SCOPE 2. REFERENCE 3. PERSONNEL 4. IDENTIFICATION OF FILM 5. EQUIPMENT/MATERIAL EQUIPMENT/MATERIAL 6. TECHNIQUE 7. IQI 8. LOCATION MARKER 9. GEOMETRIC UNSHARPNESS 10. BACK SCATTER RADIATION 11. EXPOSURE 12. DENSITY 13. DARK ROOM 14. FILM PROCESSING 15. QUALITY OF RADIOGRAPHS 16. EVALUATION 17. ACCEPTANCE CRITERIA 18. DOCUMENTS 19. SAFETY

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1.0


SCOPE:

This procedure describes are method & techniques of radiographic examination of butt welds of piping construction work of MSQ Up gradation Project, IOCL Panipat. . 2.0

REFERENCE:

2.1

ASME SEC. V Article – 2 - Non destructive Testing – Radiographic Examination.

2.2

ANSI B 31.3 (For acceptance Standard)- Code for Processing Piping.

2.3

ASNT

Recommended

practice:

SNT-TC-1A-Personnel

qualification

and

certification in Non destructive testing. 2.4

ABB Specification No.-00000-SW-231

3.0

PERSONNEL:

All radiography activities shall be carried out by BARC certified personnel only. Radiography shall be evaluated by certified ASNT/ISNT level II personnel. Certificate of RSO / site-in-charge, Radiographers shall be submitted. 4.0

IDENTIFICATION OF FILM :

Each radiograph shall have permanent identification to establish its precise location to job at least 5mm away from the weld edge. Identification shall have minimum following requirement. 4.1

Project Identification no.

4.2

Line no.

4.3

Joint no.

4.4

X-ray unique no.

4.5

Welder no.

4.6

Thickness

4.7

Date

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LARSEN & TOUBRO LIMITED

DATE:-03.11.2007

MSQ(EPCC 1) UP GRADATION

REV.NO.- 0 PROCEDURE NO.LT/MSQ/P/ RT /009

PROCEDURE FOR RADIOGRAPHY TESTING

Any additional information shall be added as required. 5.0

EQUIPMENT/MATERIAL: 5.1

SOURCE Iridium-192/Gamma ray source as per requirement will be used.

Refer Table-1 5.2 5.2.1

FILM

ASTM CL-I or CL-II film may be used depending upon sensitivity requirement as per table below. All films to be used for radiography shall be in good condition and within the period of expiry date, marked on each individual carton by manufacturer.

Type of Source and Film to be used for Radiography: Table-I

Wall Thickness (T)

Material

Shop Welded Joints

Field Welds

in mm Source

19 ≥ T All materials

8 ≥ T < 19

Carbon Steel

Source

Film

Gamma-ray

AGFA D7 or Gamma-ray

AGFA D7 or

(Iridium 192)

Equivalent

(Iriduim 192)

Equivalent

X-ray

AGFA

X-ray /Gamm- AGFA D5 or

/Gamm-ray

or Equivalent

(Iridium 192)

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Film

D7/D5

ray 192)

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(Iridium Equivalent

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LARSEN & TOUBRO LIMITED

DATE:-03.11.2007

MSQ(EPCC 1) UP GRADATION PROCEDURE FOR RADIOGRAPHY TESTING

<8

REV.NO.- 0 PROCEDURE NO.LT/MSQ/P/ RT /009

CS materials Gamma-ray

AGFA D4 or Gamma-ray

AGFA

other

Equivalent

D4/D2

than (Iridium 192)

(Iridium 192)

100% RT

or

Equivalent

It shall be ensured that the required sensitivity is achieved using the above films.

5.2.2

If the required sensitivity is not achieved consistently, fine grain films (high contrast), shall be used. (Slow speed films) A film overlap of 20mm on either side of the film shall be provided to

5.2.3

demonstrate the continuity of the welds. The minimum width of the film shall be 3”, however for elliptical (DWDI) image 5”x4” film shall be used. 5.3

LEAD INTENSIFYING SCREEN

Lead intensifying screen of thickness 0.125mm front screen and 0.25mm back screen are recommended for use. Screen shall be free from scratch marks and wrinkles. Screen showing evidence of physical damage shall be discarded. 6.0

TECHNIQUE

Any one of the following technique shall be used depend upon size, geometry & accessibility. In general, attempt shall be made to do single wall technique. 6.1

SINGLE WALL

6.1.1

Single wall image. This technique is mainly used for pipes, where the source can be safely placed inside.

6.1.2

Single wall panoramic. Single exposure, covering the whole circumference of the object. This technique is mainly used for higher diameter pipes, where the source can be safely placed inside. A minimum of three IQIs shall be placed 120 deg apart.

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6.2


DOUBLE WALL

Double wall single image

6.2.1

This technique is used where single wall technique is not practical. A minimum three exposures by placing source at 120 deg. Interval at outer surface, close to the weld. SFD is approximately equal to the diameter of the pipe. Two IQIs shall be placed on the film side, on both ends of the film, wherever possible. 6.3

DOUBLE WALL DOUBLE IMAGE (Elliptical/superimposed)

Elliptical

6.3.1

This technique is used where the diameter is 3.5” and below. Minimum two exposures at 90 deg. to each other shall be taken for the full coverage of the weld circumference. Superimposed

6.3.2

As an alternative, the weld may be radiographed with radiation beam positioned so that the images of both walls are superimposed. When complete coverage is required, a minimum of three exposures at 120 deg. apart shall be made for each joint. 7.0

IQI 7.1

Wire type ASTM/DIN pentameter of Hole type pentameter shall be used.

The IQI material selection shall be according to Standard practice SE 1025 or SE747, as applicable as shall be radiographycally similar to the material being radiographed. The thickness on which the IQI is based shall be the nominal single wall thickness plus the maximum permitted reinforcement thickness as per referencing code section. The designated hole IQI or essential wire shall be as specified in table T-276. Alternatively IQI design as per T-233.2 may be permitted. PLACEMENT OF IQI

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IQI shall be placed on source side. Where accessibility prevents hand placing IQI on source side, it shall be placed on film side with lead letter “F” on the IQI or adjacent to it. However, IQI identification shall not mask the area of interest including HAZ. PROCEDURE DEMONSTRATION:

7.3

Demonstration of the density and IQI image requirement shall be considered satisfactory evidence of compliance with this procedure. During establishing radiographic procedure, source side pentameters to be used. NUMBER OF IQI

7.4 7.4.1

Each radiograph have at least one IQIs.

7.4.2

When a joint is radiographed by panoramic view in one exposure, by placing source at the centre, the entire circumference can be radiographed by placing at least three IQIs kept at 120° apart. 8.0

LOCATION MARKER:

Lead letters shall be used as location marker. Location marker shall appear as radiography image and shall not be at the area interest. Location marker shall be kept on the job itself. Placement of location marker (film/source side) shall be as per Article II of ASME Sec.V. 9.0

GEOMETRIC UNSHARPNESS(Ug):

9.1

The source to film distance shall be maintained in such a manner that the geometric un sharpness does not exceed the specified limits. Geometric Unsharpness (Ug) is determined by the formula Ug=Fd/D where. F: Source size in mm (Maximum projected dimension of radiation source or Diagonal distance for rectangular shape) D: Distance in mm from source to weld or object to be radiographed (source side surface) d: Distance in mm from source side of the weld or object being radiographed to

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the film (Material thickness).

10.0

BACK SCATTER RADIATION:

A lead letter ‘B’ of ½” size (min) & 1/16” thick (min) should be attached at the back of film holder to check back scatter radiation. 11.0

EXPOSURE:

The required exposure time shall be calculated from exposure chart or slide rules. Exposure calculations may also be used if charts and rules are not available 12.0

DENSITY:

For X-ray, Radiography density permissible range would be 1.8 to 4.0 H & D. For Gamma ray, Radiography density permissible range would be 2.0 to 4.0 H&D The density variation over the area of interest shall be with minus 15% or plus 30% of the density measured near the required wire or over the STEP HOLE type IQI. If the shim is used under the IQI density variation may exceed more than 30% 13.0

DARK ROOM

13.1

shall be located at an environment free from, dust, fume, excessive heat and radiation. Safe lights be checked to prevent fogging of films. Unexposed films would be kept in vertical position to prevent pressure mark.

13.2 14.0

FILM PROCESSING :

Film processing shall be done in air conditioned dark room. Manual film processing shall be carried out as per the guide lines of SE-94, Film processing chemicals shall be procured from reputed manufacturer and shall not be used after expiry date. The solutions shall be prepared as per Manufacture’s recommendation. The film shall be developed at 20° C and in accordance with the Manufacture’s recommendation. 15.0

QUALITY OF RADIOGRAPHS:

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The films submitted for evaluation shall be free from blemishes to the extent that they do not mask with image of any discontinuity in the area of interest of the subject being radiographed. Such blemishes include, but are not limited to: i.

16.0

Fogging

ii.

Processing defects such as streaks, watermarks, chemical stains,

iii.

Scratches, finger marks, crimps, dirtiness, static marks, smudges

iv.

False indications due to defective screens EVALUATION:

Qualified RT Level II personnel meeting the requirements of SNT-TC-IA of ASNT and authorized Toyo Inspector shall evaluate the radiographs. After review by Toyo, radiographs shall be offered to EIL for their review and acceptance. 17.0

ACCEPTANCE CRITERIA:

Acceptance criteria shall be s per ASME B.31.3 Table 341.3.2 and applicable specifications. 18.0

DOCUMENTS:

Reports shall be maintained in Formats No. LT/MSQ/PIPE/RGM/013 & LT/MSQ/PIPE/RGI/014 and copy shall be forwarded to PMC on daily basis.

All documents required by statutory bodies are to be maintained and kept at site. 19.0 19.1

SAFETY:

Precautions shall be taken as per HSE requirement of the Project as well BARC requirements

19.2

Radiography source shall be stored in a pit in an exclusive storage room with lock and key arrangement. This pit shall be approved by BARC. Source transfer certificate, Pit room approval certificate form BARC shall be furnished to PMC.

19.3 19.3.1

During radiography the following precaution shall be taken. Cordoning of area

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19.3.2

Display of radiation symbols.

19.3.3

Display of red lights.

19.3.4

Radiations level check by Dosimeter / Radiation survey meter. 19.4

Permit for carrying out radiography, as applicable shall be obtained.

19.5

Radiographers shall wear film badges approved by BARC.

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PROCEDURE-FOR-RADIOGRAPHY-TESTING

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