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LECOEUR ELECTRONIQUE
The Specialist of electronics for ultrasonic testing.

2158 views
03:10 Sep-17-2008
Luis Ganhao
MFL vs. GUL

Which is the advantage of MFL regarding to GUL inspection in pipelines?


 
04:45 Sep-20-2008
mj
Re: MFL vs. GUL Not many sure. MFL moving through out the pipeline so maybe little visual inspection is more than GUL, but lot of disadvantages compared with GUL.
1. Pipelines need to be supported GUL not required supports.
2. Support area not possible with MFL mean time GUL can inspect a clean Support easily.
3. Road crossing can't inspect with MFL mean time GUL can inspect at least 12 meter RC from both side.
4. Coated Pipe Not possible with MFL mean time GUL can inspect with coating.
5. Insulation Line Not possible with MFL but GUL covers insulation line with a small area removal.
6. High Elevation area scaffolding required for MFL but GUL will do with out scaffolding...

Another 10 more points I can point out.

Also please note that GUL is not a Final inspection tool, it’s just helping manual UT people to find exact defect locations in a pipeline, but sure compare to MFL GUL is a good screening tool

----------- Start Original Message -----------
: Which is the advantage of MFL regarding to GUL inspection in pipelines?
------------ End Original Message ------------




 
02:13 Sep-20-2008

Michel Couture

NDT Inspector,
consultant,
Canada,
Joined Sep 2006
818
Re: MFL vs. GUL Hiu Guys,

I'm not in the petro industry, so could someone tell me what GUL stands for?

Much appreciated,

Michel
----------- Start Original Message -----------
: Not many sure. MFL moving through out the pipeline so maybe little visual inspection is more than GUL, but lot of disadvantages compared with GUL.
: 1. Pipelines need to be supported GUL not required supports.
: 2. Support area not possible with MFL mean time GUL can inspect a clean Support easily.
: 3. Road crossing can't inspect with MFL mean time GUL can inspect at least 12 meter RC from both side.
: 4. Coated Pipe Not possible with MFL mean time GUL can inspect with coating.
: 5. Insulation Line Not possible with MFL but GUL covers insulation line with a small area removal.
: 6. High Elevation area scaffolding required for MFL but GUL will do with out scaffolding...
: Another 10 more points I can point out.
: Also please note that GUL is not a Final inspection tool, it’s just helping manual UT people to find exact defect locations in a pipeline, but sure compare to MFL GUL is a good screening tool
: : Which is the advantage of MFL regarding to GUL inspection in pipelines?
------------ End Original Message ------------




 
02:47 Sep-20-2008

Paul Robertson

,
Netherlands,
Joined Jun 2003
12
Re: MFL vs. GUL Hi Michel,
In fact I believe GUL is an acronym for the company - Guided Ultrasonics Limited- from the UK.
These guys manufacture a guided wave pipeline inspection tool amongst other things.
So to apply the term 'GUL', for guided wave inspection, is probably not correct as there are other inspection tools that utilise guided waves to inspect pipelines, and those manufacturers may not thank you for referring to their equipment as a GUL instrument.
With regards to comparison with MFL - there really is a host of considerations to make, after all guided waves is essentially a remotely applied technology, MFL requires physical presence/coverage - advantages in both technologies. Its a tough question to give a 'straightforward' answer, well thats just my thoughts anyhow.
Cheers
Paul


----------- Start Original Message -----------
: Hiu Guys,
: I'm not in the petro industry, so could someone tell me what GUL stands for?
: Much appreciated,
: Michel
: : Not many sure. MFL movingthrough out the pipeline so maybe little visual inspection is more than GUL, but lot of disadvantages compared with GUL.
: : 1. Pipelines need to be supported GUL not required supports.
: : 2. Support area not possible with MFL mean time GUL can inspect a clean Support easily.
: : 3. Road crossing can't inspect with MFL mean time GUL can inspect at least 12 meter RC from both side.
: : 4. Coated Pipe Not possible with MFL mean time GUL can inspect with coating.
: : 5. Insulation Line Not possible with MFL but GUL covers insulation line with a small area removal.
: : 6. High Elevation area scaffolding required for MFL but GUL will do with out scaffolding...
: : Another 10 more points I can point out.
: : Also please note that GUL is not a Final inspection tool, it’s just helping manual UT people to find exact defect locations in a pipeline, but sure compare to MFL GUL is a good screening tool
: : : Which is the advantage of MFL regarding to GUL inspection in pipelines?
------------ End Original Message ------------




 
08:48 Sep-21-2008

Sang Kim

Consultant, NDT Trainer
Guided Wave Analysis LLC,
USA,
Joined Feb 2008
44
Re: MFL vs. GUL Hello Michel and Paul,
I also agree on Paul’s explanation about GUL. I believe that the title should be MFL versus GW where MFL and GW stand for Magnetic Flux Leakage and Guided Wave, respectively.

MFL (Magnetic Flux Leakage) is a nondestructive method detecting localized defects in ferromagnetic materials such as carbon steel, ferritic and martensitic stainless steel. The MFL detects defect with the following procedure: 1) Apply strong magnetic field in the ferromagnetic material; 2) Measure the magnetic field on the surface of ferromagnetic material using MFL sensors; and 3) Find defect with the variation of magnetic field around the defect. Therefore, the MFL is only applied to ferromagnetic material, and it is localized inspection tool, i.e. the probe should be located near or at the defect location.

GW (Guided Wave) is a nondestructive method detecting localized or generalized corrosion defect or crack in material with low-frequency ultrasonic guided wave. Because it uses ultrasonic wave, it can be used to any material in which the ordinary UT (ultrasonic test) is performed. GW is applied to any structure that has boundary such as pipe, plate, tube, wire, cables, etc. The GW propagates the structure by filling the whole cross-sectional area of the structure and by satisfying the boundary condition of the structure. The GW inspection is used to indicate the defect location and estimate the defect size, mostly the cross-sectional area of defect. For filling the whole cross-sectional area of the structure, it uses lower frequency than that of ordinary UT. The frequency range is usually less than 500 kHz. The merit of GW inspection is that the ultrasonic guided wave propagates long distance along the structure and finds defects at remote location. If the attenuation is very low in a structure, it can inspect 200 meters with one GW probe installed. The following frequencies are usually used due to different diameter or thickness of the structure:
Pipeline --- 20 to 250 kHz
Plate --- 64 to 250 kHz
Heat exchanger tube --- 128 to 500 kHz
Rod --- 20 to 64 kHz
Cable --- 4 to 32 kHz

The following rule is applied for selection of the operating frequency in GW inspection. The operating frequency: 1) is lowered as the structure is thicker; 2) is decreased if the inspection range is long; 3) is lowered if the structure has high attenuation due to bonded insulation such as bitumen coating, soil contact, or PE coating; 4) is increased if the structure has attachments such as clamp and pipe support; and 5) is increased for finding relatively small defect.

I will explain GW in pipe as an example. The GW inspection in piping uses torsional mode or longitudinal mode in non-dispersive frequency region. The selection of non-dispersive GW mode is because it propagates long distance without signal broadening. It usually uses 1 or 2 cycles because it increases the spatial resolution along the propagation direction. Using more than 3 cycles reduces the spatial resolution in low-frequency operating, for example, the GW signal at 4 cycles has the signal width of 16 inches at 32-kHz torsional mode in steel pipe. If the pipe is coated with PE or bitumen, the operating frequency should be less than 45 kHz because of the high attenuation at high frequency. If the pipe has pipe support, clamp, or wire tie in aboveground insulated pipe (many pipelines in refinery, chemical and petrochemical plant that are usually not insulated with bitumen or PE), it is recommended to be tested at higher frequencies than 60 kHz because the low-frequency GW loses much energy with the interaction with them. The strong interaction generates reflected signal at them and sometimes trailing signals. The high-frequency GW (higher than 100 kHz) reflects a small signal or no signal at these geometric features. Therefore it can propagate longer distance and allows finding defect under these geometric features.

In conclusion, both MFL and GW are used for inspecting pipe, plate, HX tube, cable, rod, etc. But the MFL is limited to testing only ferromagnetic material of these structures. GW can be used to inspect any material such as composite if the ordinary UT can be used. The MFL is localized inspection tool, i.e. the probe needs to be located near or at the defect location. The GW is remote inspection tool because GW is transmitted along the structure and reflected from the defect at a long distance from several inches to 200 meters depending on the operating frequency and attenuation of the structure. The GW is usually used for surveying the long length of structure, but the MFL, UT, or RT is used for verifying, sizing, and characterizing of the indications found with GW inspection.

If you want to know the performance and field application of GW for pipe, plate, anchor rod and angle beam in transmission line, heat exchanger tube, composite plate, and bridge cable, please refer to this website (http://www.gwanalysis.com/Application.html). If you learn more about GW, please contact me at skim@gwanalysis.com.
Thanks.
Sang


----------- Start Original Message -----------
: Hi Michel,
: In fact I believe GUL is an acronym for the company - Guided Ultrasonics Limited- from the UK.
: These guys manufacture a guided wave pipeline inspection tool amongst other things.
: So to apply the term 'GUL', for guided wave inspection, is probably not correct as there are other inspection tools that utilise guided waves to inspect pipelines, and those manufacturers may not thank you for referring to their equipment as a GUL instrument.
: With regards to comparison with MFL - there really is a host of considerations to make, after all guided waves is essentially a remotely applied technology, MFL requires physical presence/coverage - advantages in both technologies. Its a tough question to give a 'straightforward' answer, well thats just my thoughts anyhow.
: Cheers
: Paul
:
: : Hiu Guys,
: : I'm not in the petro industry, so could someone tell me what GUL stands for?
: : Much appreciated,
: : Michel
: : : Not many sure. MFL moving through out the pipeline so maybe little visual inspection is more than GUL, but lot of disadvantages compared with GUL.
: : : 1. Pipelines need to be supported GUL not required supports.
: : : 2. Support area not possible with MFL mean time GUL can inspect a clean Support easily.
: : : 3. Road crossing can't inspect with MFL mean time GUL can inspect at least 12 meter RC from both side.
: : : 4. Coated Pipe Not possible with MFL mean time GUL can inspect with coating.
: : : 5. Insulation Line Not possible with MFL but GUL covers insulation line with a small area removal.
: : : 6. High Elevation area scaffolding required for MFL but GUL will do with out scaffolding...
: : : Another 10 more points I can point out.
: : : Also please note that GUL is not a Final inspection tool, it’s just helping manual UT people to find exact defect locations in a pipeline, but sure compare to MFL GUL is a good screening tool
: : : : Which is the advantage of MFL regarding to GUL inspection in pipelines?
------------ End Original Message ------------




 
00:31 Sep-22-2008
Peter Philipp
Re: MFL vs. GUL Hi,

MFL and GUL are Magnetic Flux Leakage and GUL tends to be used, in the US in particular, for Guided Wave inspection. GUL stands for is Guided Ultrasonics Limited a company based in the UK that tends to be seen as the market leader as it has developed the technology in many areas such as subsea, tethered GW pig, rail and tubetesting (heat exchangers) as well as standard pipe testing. The technique was originally developed to look for CUI Corrosion Under Insulation without the need to remove all the lagging. Since then many more applications have been developed with the main emphasis on rapid screening and difficult to access areas. You can get more info on www.guided-ultrasonics.com

I am not an expert on MFL but the 2 techniques are quite different with the main difference being that MFL measures only where the probe is located whereas Guided waves detect features some distance from the probes typically about 30m but can be as much as 100m in ideal conditions.

Hope this helps but please contact me if you want any more info.

----------- Start Original Message -----------
: Hiu Guys,
: I'm not in the petro industry, so could someone tell me what GUL stands for?
: Much appreciated,
: Michel
: : Not many sure. MFL moving through out the pipeline so maybe little visual inspection is more than GUL, but lot of disadvantages compared with GUL.
: : 1. Pipelines need to be supported GUL not required supports.
: : 2. Support area not possible with MFL mean time GUL can inspect a clean Support easily.
: : 3. Road crossing can't inspect with MFL mean time GUL can inspect at least 12 meter RC from both side.
: : 4. Coated Pipe Not possible with MFL mean time GUL can inspect with coating.
: : 5. Insulation Line Not possible with MFL but GUL covers insulation line with a small area removal.
: : 6. High Elevation area scaffolding required for MFL but GUL will do with out scaffolding...
: : Another 10 more points I can point out.
: : Also please note that GUL is not a Final inspection tool, it’s just helping manual UT people to find exact defect locations in a pipeline, but sure compare to MFL GUL is a good screening tool
: : : Which is the advantage of MFL regarding to GUL inspection in pipelines?
------------ End Original Message ------------




 
04:47 Sep-22-2008

Sang Kim

Consultant, NDT Trainer
Guided Wave Analysis LLC,
USA,
Joined Feb 2008
44
Re: MFL vs. GUL Hello Michel and Paul,
I also agree on Paul’s explanation about GUL. I believe that the title should be MFL versus GW where MFL and GW stand for Magnetic Flux Leakage and Guided Wave, respectively.

MFL (Magnetic Flux Leakage) is a nondestructive method detecting localized defects in ferromagnetic materials such as carbon steel, ferritic and martensitic stainless steel. The MFL detects defect with the following procedure: 1) Apply strong magnetic field in the ferromagnetic material; 2) Measure the magnetic field on the surface of ferromagnetic material using MFL sensors; and 3) Find defect with the variation of magnetic field around the defect. Therefore, the MFL is only applied to ferromagnetic material, and it is localized inspection tool, i.e. the probe should be located near or at the defect location.

GW (Guided Wave) is a nondestructive method detecting localized or generalized corrosion defect or crack in material with low-frequency ultrasonic guided wave. Because it uses ultrasonic wave, it can be used to any material in which the ordinary UT (ultrasonic test) is performed. GW is applied to any structure that has boundary such as pipe, plate, tube, wire, cables, etc. The GW propagates the structure by filling the whole cross-sectional area of the structure and by satisfying the boundary condition of the structure. The GW inspection is used to indicate the defect location and estimate the defect size, mostly the cross-sectional area of defect. For filling the whole cross-sectional area of the structure, it uses lower frequency than that of ordinary UT. The frequency range is usually less than 500 kHz. The merit of GW inspection is that the ultrasonic guided wave propagates long distance along the structure and finds defects at remote location. If the attenuation is very low in a structure, it can inspect 200 meters with one GW probe installed. The following frequencies are usually used due to different diameter or thickness of the structure:
Pipeline --- 20 to 250 kHz
Plate --- 64 to 250 kHz
Heat exchanger tube --- 128 to 500 kHz
Rod --- 20 to 64 kHz
Cable --- 4 to 32 kHz

The following rule is applied for selection of the operating frequency in GW inspection. The operating frequency: 1) is lowered as the structure is thicker; 2) is decreased if the inspection range is long; 3) is lowered if the structure has high attenuation due to bonded insulation such as bitumen coating, soil contact, or PE coating; 4) is increased if the structure has attachments such as clamp and pipe support; and 5) is increased for finding relatively small defect.

I will explain GW in pipe as an example. The GW inspection in piping uses torsional mode or longitudinal mode in non-dispersive frequency region. The selection of non-dispersive GW mode is because it propagates long distance without signal broadening. It usually uses 1 or 2 cycles because it increases the spatial resolution along the propagation direction. Using more than 3 cycles reduces the spatial resolution in low-frequency operating, for example, the GW signal at 4 cycles has the signal width of 16 inches at 32-kHz torsional mode in steel pipe. If the pipe is coated with PE or bitumen, the operating frequency should be less than 45 kHz because of the high attenuation at high frequency. If the pipe has pipe support, clamp, or wire tie in aboveground insulated pipe (many pipelines in refinery, chemical and petrochemical plant that are usually not insulated with bitumen or PE), it is recommended to be tested at higher frequencies than 60 kHz because the low-frequency GW loses much energy with the interaction with them. The strong interaction generates reflected signal at them and sometimes trailing signals. The high-frequency GW (higher than 100 kHz) reflects a small signal or no signal at these geometric features. Therefore it can propagate longer distance and allows finding defect under these geometric features.

In conclusion, both MFL and GW are used for inspecting pipe, plate, HX tube, cable, rod, etc. But the MFL is limited to testing only ferromagnetic material of these structures. GW can be used to inspect any material such as composite if the ordinary UT can be used. The MFL is localized inspection tool, i.e. the probe needs to be located near or at the defect location. The GW is remote inspection tool because GW is transmitted along the structure and reflected from the defect at a long distance from several inches to 200 meters depending on the operating frequency and attenuation of the structure. The GW is usually used for surveying the long length of structure, but the MFL, UT, or RT is used for verifying, sizing, and characterizing of the indications found with GW inspection.

If you want to know the performance and field application of GW for pipe, plate, anchor rod and angle beam in transmission line, heat exchanger tube, composite plate, and bridge cable, please refer to this website (http://www.gwanalysis.com/Application.html). If you learn more about GW, please contact me at skim@gwanalysis.com.
Thanks.
Sang


----------- Start Original Message -----------
: Hi Michel,
: In fact I believe GUL is an acronym for the company - Guided Ultrasonics Limited- from the UK.
: These guys manufacture a guided wave pipeline inspection tool amongst other things.
: So to apply the term 'GUL', for guided wave inspection, is probably not correct as there are other inspection tools that utilise guided waves to inspect pipelines, and those manufacturers may not thank you for referring to their equipment as a GUL instrument.
: With regards to comparison with MFL - there really is a host of considerations to make, after all guided waves is essentially a remotely applied technology, MFL requires physical presence/coverage - advantages in both technologies. Its a tough question to give a 'straightforward' answer, well thats just my thoughts anyhow.
: Cheers
: Paul

<< I don't understand why these message were not distributed through email. I hope some explanation from www.ndt.net.>>
----------- Start Original Message -----------
: Hi,
: MFL and GUL are Magnetic Flux Leakage and GUL tends to be used, in the US in particular, for Guided Wave inspection. GUL stands for is Guided Ultrasonics Limited a company based in the UK that tends to be seen as the market leader as it has developed the technology in many areas such as subsea, tethered GW pig, rail and tubetesting (heat exchangers) as well as standard pipe testing. The technique was originally developed to look for CUI Corrosion Under Insulation without the need to remove all the lagging. Since then many more applications have been developed with the main emphasis on rapid screening and difficult to access areas. You can get more info on www.guided-ultrasonics.com
: I am not an expert on MFL but the 2 techniques are quite different with the main difference being that MFL measures only where the probe is located whereas Guided waves detect features some distance from the probes typically about 30m but can be as much as 100m in ideal conditions.
: Hope this helps but please contact me if you want any more info.
: : Hiu Guys,
: : I'm not in the petro industry, so could someone tell me what GUL stands for?
: : Much appreciated,
: : Michel
: : : Not many sure. MFL moving through out the pipeline so maybe little visual inspection is more than GUL, but lot of disadvantages compared with GUL.
: : : 1. Pipelines need to be supported GUL not required supports.
: : : 2. Support area not possible with MFL mean time GUL can inspect a clean Support easily.
: : : 3. Road crossing can't inspect with MFL mean time GUL can inspect at least 12 meter RC from both side.
: : : 4. Coated Pipe Not possible with MFL mean time GUL can inspect with coating.
: : : 5. Insulation Line Not possible with MFL but GUL covers insulation line with a small area removal.
: : : 6. High Elevation area scaffolding required for MFL but GUL will do with out scaffolding...
: : : Another 10 more points I can point out.
: : : Also please note that GUL is not a Final inspection tool, it’s just helping manual UT people to find exact defect locations in a pipeline, but sure compare to MFL GUL is a good screening tool
: : : : Which is the advantage of MFL regarding to GUL inspection in pipelines?
------------ End Original Message ------------




 
03:38 Sep-23-2008

Michel Couture

NDT Inspector,
consultant,
Canada,
Joined Sep 2006
818
Re: MFL vs. GUL Gentlemen,

Thank you very much with your explaination of MFL and GUL. As I replied to someone by email, NDT is such a vast technological field that it is impossible for one to know everything. This forum and people like you is really the place where one can expand their knowledge.

I did use MFL a couple of time to do floor inspection of fuel tanks, but Ontario, Canada is not the "oil capital" of Canada. You have to go to Saskatchewan and Alberta for that. So pipeline work works are few and far in between. Thanks to all of you guys, I do have a better understanding of this part of UT.

Cheerio's

Michel

----------- Start Original Message -----------
: Hello Michel and Paul,
: I also agree on Paul’s explanation about GUL. I believe that the title should be MFL versus GW where MFL and GW stand for Magnetic Flux Leakage and Guided Wave, respectively.
: MFL (Magnetic Flux Leakage) is a nondestructive method detecting localized defects in ferromagnetic materials such as carbon steel, ferritic and martensitic stainless steel. The MFL detects defect with the following procedure: 1) Apply strong magnetic field in the ferromagnetic material; 2) Measure the magnetic field on the surface of ferromagnetic material using MFL sensors; and 3) Find defect with the variation of magnetic field around the defect. Therefore, the MFL is only applied to ferromagnetic material, and it is localized inspection tool, i.e. the probe should be located near or at the defect location.
: GW (Guided Wave) is a nondestructive method detecting localized or generalized corrosion defect or crack in material with low-frequency ultrasonic guided wave. Because it uses ultrasonic wave, it can be used to any material in which the ordinary UT (ultrasonic test) is performed. GW is applied to any structure that has boundary such as pipe, plate, tube, wire, cables, etc. The GW propagates the structure by filling the whole cross-sectional area of the structure and by satisfying the boundary condition of the structure. The GW inspection is used to indicate the defect location and estimate the defect size, mostly the cross-sectional area of defect. For filling the whole cross-sectional area of the structure, it uses lower frequency than that of ordinary UT. The frequency range is usually less than 500 kHz. The merit of GW inspection is that the ultrasonic guided wave propagates long distance along the structure and finds defects at remote location. If the attenuation is very low in a structure, it can inspect 200 meters with one GW probe installed. The following frequencies are usually used due to different diameter or thickness of the structure:
: Pipeline --- 20 to 250 kHz
: Plate --- 64 to 250 kHz
: Heat exchanger tube --- 128 to 500 kHz
: Rod --- 20 to 64 kHz
: Cable --- 4 to 32 kHz
: The following rule is applied for selection of the operating frequency in GW inspection. The operating frequency: 1) is lowered as the structure is thicker; 2) is decreased if the inspection range is long; 3) is lowered if the structure has high attenuation due to bonded insulation such as bitumen coating, soil contact, or PE coating; 4) is increased if the structure has attachments such as clamp and pipe support; and 5) is increased for finding relatively small defect.
: I will explain GW in pipe as an example. The GW inspection in piping uses torsional mode or longitudinal mode in non-dispersive frequency region. The selection of non-dispersive GW mode is because it propagates long distance without signal broadening. It usually uses 1 or 2 cycles because it increases the spatial resolution along the propagation direction. Using more than 3 cycles reduces the spatial resolution in low-frequency operating, for example, the GW signal at 4 cycles has the signal width of 16 inches at 32-kHz torsional mode in steel pipe. If the pipe is coated with PE or bitumen, the operating frequency should be less than 45 kHz because of the high attenuation at high frequency. If the pipe has pipe support, clamp, or wire tie in aboveground insulated pipe (many pipelines in refinery, chemical and petrochemical plant that are usually not insulated with bitumen or PE), it is recommended to be tested at higher frequencies than 60 kHz because the low-frequency GW loses much energy with the interaction with them. The strong interaction generates reflected signal at them and sometimes trailing signals. The high-frequency GW (higher than 100 kHz) reflects a small signal or no signal at these geometric features. Therefore it can propagate longer distance and allows finding defect under these geometric features.
: In conclusion, both MFL and GW are used for inspecting pipe, plate, HX tube, cable, rod, etc. But the MFL is limited to testing only ferromagnetic material of these structures. GW can be used to inspect any material such as composite if the ordinary UT can be used. The MFL is localized inspection tool, i.e. the probe needs to be located near or at the defect location. The GW is remote inspection tool because GW is transmitted along the structure and reflected from the defect at a long distance from several inches to 200 meters depending on the operating frequency and attenuation of the structure. The GW is usually used for surveying the long length of structure, but the MFL, UT, or RT is used for verifying, sizing, and characterizing of the indications found with GW inspection.
: If you want to know the performance and field application of GW for pipe, plate, anchor rod and angle beam in transmission line, heat exchanger tube, composite plate, and bridge cable, please refer to this website (http://www.gwanalysis.com/Application.html). If you learn more about GW, please contact me at skim@gwanalysis.com.
: Thanks.
: Sang
:
: : Hi Michel,
: : In fact I believe GUL is an acronym for the company - Guided Ultrasonics Limited- from the UK.
: : These guys manufacture a guided wave pipeline inspection tool amongst other things.
: : So to apply the term 'GUL', for guided wave inspection, is probably not correct as there are other inspection tools that utilise guided waves to inspect pipelines, and those manufacturers may not thank you for referring to their equipment as a GUL instrument.
: : With regards to comparison with MFL - there really is a host of considerations to make, after all guided waves is essentially a remotely applied technology, MFL requires physical presence/coverage - advantages in both technologies. Its a tough question to give a 'straightforward' answer, well thats just my thoughts anyhow.
: : Cheers
: : Paul
: << I don't understand why these message were not distributed through email. I hope some explanation from www.ndt.net.>>
: : Hi,
: : MFL and GUL are Magnetic Flux Leakage and GUL tends to be used, in the US in particular, for Guided Wave inspection. GUL stands for is Guided Ultrasonics Limited a company based in the UK that tends to be seen as the market leader as it has developed the technology in many areas such as subsea, tethered GW pig, rail and tubetesting (heat exchangers) as well as standard pipe testing. The technique was originally developed to look for CUI Corrosion Under Insulation without the need to remove all the lagging. Since then many more applications have been developed with the main emphasis on rapid screening and difficult to access areas. You can get more info on www.guided-ultrasonics.com
: : I am not an expert on MFL but the 2 techniques are quite different with the main difference being that MFL measures only where the probe is located whereas Guided waves detect features some distance from the probes typically about 30m but can be as much as 100m in ideal conditions.
: : Hope this helps but please contact me if you want any more info.
: : : Hiu Guys,
: : : I'm not in the petro industry, so could someone tell me what GUL stands for?
: : : Much appreciated,
: : : Michel
: : : : Not many sure. MFL moving through out the pipeline so maybe little visual inspection is more than GUL, but lot of disadvantages compared with GUL.
: : : : 1. Pipelines need to be supported GUL not required supports.
: : : : 2. Support area not possible with MFL mean time GUL can inspect a clean Support easily.
: : : : 3. Road crossing can't inspect with MFL mean time GUL can inspect at least 12 meter RC from both side.
: : : : 4. Coated Pipe Not possible with MFL mean time GUL can inspect with coating.
: : : : 5. Insulation Line Not possible with MFL but GUL covers insulation line with a small area removal.
: : : : 6. High Elevation area scaffolding required for MFL but GUL will do with out scaffolding...
: : : : Another 10 more points I can point out.
: : : : Also please note that GUL is not a Final inspection tool, it’s just helping manual UT people to find exact defect locations in a pipeline, but sure compare to MFL GUL is a good screening tool
: : : : : Which is the advantage of MFL regarding to GUL inspection in pipelines?
------------ End Original Message ------------




 


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