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05:46 Oct-09-2003
oba
LPG sphere legs inspection

is the any mehod to inspectlegs of LPG sphere without removing the concrete?
the concrete cracked at several places but we dont konw if there is an impact on the steel legs
thank you very much


 
09:31 Oct-09-2003
Peter Philipp
Re: LPG sphere legs inspection ----------- Start Original Message -----------
: is the any mehod to inspectlegs of LPG sphere without removing the concrete?
: the concrete cracked at several places but we dont konw if there is an impact on the steel legs
: thank you very much
------------ End Original Message ------------

I know that some of the users of our Wavemaker pipe screening equipment have done testing of sphere legs. You need to get the probe ring on the pipe so if you have say at least 1m above the concrete you can test from as high up as possible, if you do not have space above the concrete you may need to remove about 0.5m of concrete at the bottom and test up the leg.

You can visit our website www.guided-ultrasonics.com or e-mail me for further info.

Can you give me more info re location of spheres so I can advise operators of our equipment that could quote for doing the work.

Regards

Peter Philipp
for Guided Ultrasonics.



 
02:17 Oct-10-2003

Todd Allen

Consultant, Ground Penetrating Radar ( GPR )
Radarview Concrete and Underground 3D Imaging,
USA,
Joined Jan 2003
7
Re: LPG sphere legs inspection ----------- Start Original Message -----------
: is the any mehod to inspectlegs of LPG sphere without removing the concrete?
: the concrete cracked at several places but we dont konw if there is an impact on the steel legs
: thank you very much
------------ End Original Message ------------

Hello,

My company specializes in structural inspection and has performed scanning steel through concrete. In the past the "Inco-test" (pulsed eddy current) was used, however, the large footprint would incorrectly read the steel thickness due to the wire mesh reinforcement in the concrete fireproofing. Also the GUL-Wavemaker is used to screen for corrosion, however, it requires removing concrete in many cases and you will not know how bad the corrosion is (or isn't).

We use an improved pulsed eddy-current technology known as the PEC Tool. The footprint is only about .8" in diameter. We first perform a pachometer survey to locate the wire mesh and then take the thickness readings with the PEC tool between the mesh wires. This gives an accurate steel thickness without removing concrete fireproofing.

We also are able to core the fireproofing, prove our findings, and then repair the core hole with a fire-rated, shrinkage compensating repair mortar. If you need any additional information, please call me 281-705-9476.

Todd Allen
Manager
Radarview Structural and Underground Services
Phone: 281-705-9476
Fax: 281-812-6590
Email: tallen@radarview.tv





 
01:46 Oct-11-2003

John O'Brien

Consultant, -
Chevron ETC ,
USA,
Joined Jan 2000
278
Re: LPG sphere legs inspection This is a topically issue with two leg failures in recent years.

Different operators have different approaches including the GWUT approach alreday mentioned on the Forum.

Another approach is impact resonance to determine if the material is bonded to the leg. If the bond exists there can be no corrosion. This I know has been used on numerous spheres. As you are also concerned about cracks in the concrete this may be an advantageous approach.

Where are you situated in the world and I can give you local sources to contact.u


 
05:52 Oct-14-2003

Todd Allen

Consultant, Ground Penetrating Radar ( GPR )
Radarview Concrete and Underground 3D Imaging,
USA,
Joined Jan 2003
7
Re: LPG sphere legs inspection ----------- Start Original Message -----------
: This is a topically issue with two leg failures in recent years.
: Different operators have different approaches including the GWUT approach alreday mentioned on the Forum.
: Another approach is impact resonance to determine if the material is bonded to the leg. If the bond exists there can be no corrosion. This I know has been used on numerous spheres. As you are also concerned about cracks in the concrete this may be an advantageous approach.
: Where are you situated in the world and I can give you local sources to contact.u
------------ End Original Message ------------

The last comment made a good point. Impact resonance or even Impact Echo could be useful. Corrosion can still form even with a good concrete to steel bond. Concrete is basically a hard sponge - very porous. All it takes is water, chlorides, and oxygen to set off the electrical chemical corrosion process. These elements can reach the steel by migrating through the concrete or can be accelerated by cracks.
Eventually the corrosion process will break the bond as the concrete experiences a failure in tension (it will crack and start spalling).
We regularly use impact echo for the detection of delaminated concrete.

Todd Allen
Manager
Radarview Structural and Underground Services
Phone: 281-705-9476
Fax: 281-812-6590
Email: tallen@radarview.tv



 
06:46 Nov-03-2003
Maarten Robers
Re: LPG sphere legs inspection There is already quite a lot of experience in this application with RTD-INCOTEST. In France for instance it is the only qualified method. (Here it is offered in combination with Finite Element calculations).

The remark made by Todd Allen regarding the influence of wire mesh does apply to some particular situations where the mesh is too dense. In general it does not provide a problem.

The spotsize over which corrosion is detected is less of an influence in this respect. With regard to this spotsize: our experience shows that where one is foremost interested in the detection of possible corrosion, a small spotsize is of less importance then the allowance for "mis-"placement (or having the gridspot not on but next to a corrosion area).


----------- Start Original Message -----------
: is the any mehod to inspectlegs of LPG sphere without removing the concrete?
: the concrete cracked at several places but we dont konw if there is an impact on the steel legs
: thank you very much
------------ End Original Message ------------




 
02:51 Dec-23-2003
Matthew Ing
Re: LPG sphere legs inspection Hello,

Balvac have just launched a non destructive technique - AeCORR, that detects and indicates the rate of corrosion induced damage occuring within the concrete, thus eliminating the need for intrusive inspection.

Sensors mounted directly onto the surface of the concrete are able to detect active corrosion activity occuring beneath the concrete surface, providing there is good contact between the steel and concrete. If you require any further information, please contact me on the number below.

Dr Matthew Ing
AeCORR Technical Manager
Balvac Ltd
Tel: +44 (0)1773 542600
Email: matthew.ing@balvac.co.uk

----------- Start Original Message -----------
: is the any mehod to inspectlegs of LPG sphere without removing the concrete?
: the concrete cracked at several places but we dont konw if there is an impact on the steel legs
: thank you very much
------------ End Original Message ------------




 
00:11 Mar-09-2004
Richard Holliday
Re: LPG sphere legs inspection ----------- Start Original Message -----------
: is the any mehod to inspectlegs of LPG sphere without removing the concrete?
: the concrete cracked at several places but we dont konw if there is an impact on the steel legs
: thank you very much
------------ End Original Message ------------

We have developed an alternative to cement based fire protection based on epoxy intumescent technology which provides equivalent levels of fire protection and in addition is a full corrosion protection system offering proven maintenance free life in excess of 25 years. We can incorporate removable sections to allow easy access for NDT inspection (true NDT in the fact that the fire protection coating is not destroyed during the inspection process).

One things for sure, if the concrete has cracked you will almost certainly have a corrosion issue if not on the sphere legs then within the concrete fire protection that could result in it spalling in the event of a fire.


Regards,


Richard Holliday
International Coatings
Fire & Insulation Products.

E-mail: richard.holliday@uk.akzonobel.com
Cell/Mobile: +44 (0) 7899 678 585
Direct Dial: +44 (0) 1561 377 919
Direct Fax: +44 (0) 1561 377 920




 
02:48 Jun-17-2004
rajendra kumar sinha
Re: LPG sphere coating Dear sir I would like to know what are the difference if LPG SPEHRE IS COATED/ INSULATED, In the life and volumetric efficiency of storage.
In my case LPG Storage of 1500 m3 at 8.0 Kg/cm2 350c.
thanks
r k sinha
lpg plant
ongc uran
india


 
06:34 Jun-30-2006
A.V.Krishna Murthy
Re: LPG sphere legs inspection
: Hello,
: : : thank you very much

Pl. tell us whether you will carry out in India for our spheres.


 
20:42 Oct-17-2009
Muhammad N Iqbal, P.Engr.
Re: LPG sphere legs inspection In Reply to oba at 05:46 Oct-09-2003 (Opening).

Download RTD-INCOTEST and Sphere leg inspection

Please check the power point presentation.

This is the method called RTD-Incotest (Pulsed Eddy Current).
no need to remove the fire proofing or insulation.

Regards,

Muhammad N Iqbal, P.Engr.
MS, Metallurgical
Muhammad.Iqbal@applusrtd.com
 
08:26 Oct-19-2009

Godfrey Hands

Engineering,
PRI Nadcap,
United Kingdom,
Joined Nov 1998
281
Re: LPG sphere legs inspection In Reply to oba at 05:46 Oct-09-2003 (Opening).

Goodday,
I missed this posting when it was first published.

One respondent has suggested Guided Wave Ultrasonics using the "GUL" system.
There are three main competitive systems world-wide, and the one that has what I feel is the best chance is the MSS (Magneto-Strictive Sensor) system.
It operates on the principle of guided waves, but (like the GUL) it is initially necessary to remove a strip of concrete. However, the sensors employed on this are relatively low-cost and small in section, and once applied, the concrete can be re-instated OVER THE SENSOR.
This means that it is simple to re-test without removing the concrete the next time.
An additional advantage is that with a permanently mounted sensor, you can take a "Fingerprint" of the leg, and on subsequent inspections, the fingerprint can be digitally subtracted from the new recording to highlight any small changes.
Suggest you start off by contacting Dr. Dulay at NDT Consultants in the UK at Dulay@ndt-consultants.co.uk who is marketing this technology in most of Europe and most of Asia.

Godfrey

 
23:03 May-21-2015
Dave Russell
Re: LPG sphere legs inspection In Reply to Godfrey Hands at 08:26 Oct-19-2009 .

A new, electro-magnetic inspection technique known as "Bracelet Probe" can inspect through concrete, including mesh and studs, to detect CUF (corrosion under Fireproofing). It is a low-frequency, AC scanning technique that interrogates between 8" and 40" per scan. The scanning head can be deployed by hand or with robotics. The technique detects changes in thickness rather than measuring remaining wall. Depth of corrosion is inferred by the signal amplitude.
The technique has been demonstrated and trialled by Imperial Oil and Acuren over the past two years. For more info write info@russelltech.com or call +1-800-661-0126 and ask for Dave Russell or Ankit Vajpayee.

 


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