tankpac sample report

Doc. No. 520 ISO 9001:2000 Document Date : 01/11/05 Issue No. 5 Attachment 1 – Sample Report Copy No. © Physical Acoustics Ltd. 2005 520 Attachment1.doc

TANKPAC – TANK FLOOR MONITORING REPORT

TANK No.: T-1234

FT Report No.: 5678

Test Date: 23/10/2000

Company: A. Refinery

Location: Somewhere

By: A.Engineer

PAC Level II ___________________

(AE-TANKPAC per ASNT-TC-1A)

Reviewed by:

PAC Level II (AE) ___________________

Approved by:

PAC Level III (AE) ___________________

Doc. No. 520 ISO 9001:2000 Document Date : 01/11/05 Issue No. 5 Attachment 1 – Sample Report Copy No. © Physical Acoustics Ltd. 520 Attachment1.doc

CONTENTS

1 INTRODUCTION AND BACKGROUND 2 TEST PROCEDURES

3 LIMITATIONS 4 RESULTS 5 FIGURES 6 TANK AND TEST DATA 7 EXPLANATION AND GLOSSARY OF ABBREVIATIONS CONDITION MONITORING FOR TANK FLOORS

Doc. No. 520 ISO 9001:2000 Document Date : 01/11/05 Issue No. 5 Attachment 1 – Sample Report Copy No. © Physical Acoustics Ltd. 520 Attachment1.doc 1. INTRODUCTION AND BACKGROUND This report describes work carried out on site and concerns the monitoring of storage tank(s) to evaluate the condition of the tank floor(s) as described by in PAL TANKPAC tank floor test method statement (Doc. 518). A Physical Acoustics TB-2000 testing system was used. Independent published verification of the TANKPAC test procedure by the oil industry, based on 600 tests carried out prior to June 1996, may be found at: www.ndt.net/article/ecndt98/chemical/095/095.htm The purpose of the test is to establish tank floor condition in order to help make decisions on tank maintenance timing and priority, the method forms part of an RBI program. 2. TEST PROCEDURES Following tank isolation and settling, sensors are mounted around the tank circumference, tested in situ, and the tank monitored for a test period of one hour or more following Physical Acoustics TANKPAC test Procedures for Tank Floor testing, current issue (Doc.501). Following data collection and removal of extraneous noise sources, four types of analysis are carried out:

All activity from the tank recorded above the system threshold, is graded A-E (least to most) according to PAL experience and corrected for tank type, size, test threshold and product.

All activity located on the tank floor, including corrosion, leakage, over-stress, etc. is shown on the “All Data” tank plot, based on a first-hit location analysis of signal hitting three sensors.

An analysis of data (found by experience) to be more characteristic of severe localised corrosion, “Potential Leakage” sites, is shown on the “Potential Leak” or PLD location plots.

Further evaluation of any highly active sources, for example to improve location accuracy, or to evaluate source activity and characteristics.

All tests are carried out to standard Physical Acoustics Ltd. procedures, the field worksheets (Doc.502) are kept as a quality control record together with the digital test data, with an overall quality plan (Doc.503) for the individual tank, according to PAL ISO 9001:2000 procedures. Engineers are trained and certified specifically in TANKPAC procedures, (training, experience, written, and practical examinations). Engineers are also certified level II-AE per ASNT-TC-1A. Data and test results for the tank are detailed in the figures and appendix with the location plots. 3. LIMITATIONS The method is experience-based and is able to determine overall floor condition, i.e. good, intermediate or poor, from the active corrosion, in order to determine if further (internal) inspection and repairs are required; it is therefore a very cost-effective maintenance-planning tool. It does not give information on remaining thickness, although it is able to separate badly corroded tanks from non-corroded tanks. Sources of emissions that are located may represent between 3% and 30% of the data (OAL/PLL %), so this location information must be used with care. The method is not suitable for assessing the internal condition of tanks where corrosion scale is periodically removed, mechanically or chemically, as this “resets” the condition, or whose contents change short-term, hence changing internal corrosion conditions. Corrosion that does not result in any scale formation, for example certain types of MIC, may not be detected. Tank floors that are leaking at the time of test: Small leaks can be located; these do not have a significant effect on the test result and overall grading of the tank. It must be noted, however, that an actively corroding floor will mask the emissions from small leaks. Large leaks can also be located but are likely to mask other activity from the floor.


4. RESULTS 4.1 Details of the standard test and analysis graphics are shown in the figures, a summary

of the test results is given below:

4.2 Test Observations: Operators walking around tank.

4.3 Noise sources identified and removed from the data prior to analysis: Wind noise and noise from operators walking around tank.

4.4 AE source detail: Activity in the central region of the tank floor.

4.5 Evaluation of overall data and located sources: TANK I.D.: T-1234

Overall TANKPAC grade: C ASL: 16 TANKPAC "potential leak" sources: 1 - grade sources: 3 Sources

2 - grade sources: None

3 - grade sources: 1 Source

4 - grade sources: None

5 - grade sources: None Notes: Highly active and concentrated sources in the "all" or "potential leak" data may indicate a possible leak, however this can only be positively confirmed with a co-incident increase in ASL, or

exceptionally high source event rate. Where this is confirmed it will be clearly stated "probable leak".

4.6 Composite Grade III Maintenance action taken with a tank is a matter for the owner, taking into account all possible factors. The "composite grade" gives a guide for prioritisation and re-test. Typical practice by TANKPAC users is to re-test or schedule for outage as below:

Composite Grade Typical Re-test Period I 4-5 Years II 2 Years III 1 Year* IV 0.5 Year* * schedule for Inspection


Tank T-1234 Located Data (23%) Overall Grade C Composite Grade III


Tank T-1234 Located ‘All Data’ 3D View


Tank T-1234 Located ‘Potential Leak’ Data (28%) ‘Potential Leak’ Grade 3


Tank T-1234 Located ‘Potential Leak’ Data 3D View

Doc. No. 520 ISO 9001:2000 Document Date : 01/11/05 Issue No. 5 Attachment 1 – Sample Report Copy No. © Physical Acoustics Ltd. 2005 520 Attachment1.doc TANKPAC TEST DATA 21 October 2005 Customer: A Refinery Location: Somewhere Contact: Mr.A.Client Diameter, m: 70.0 m Tank No.: T-1234 Operating Temp, °C: 16 deg C Normal Contents: Crude Oil Category/Group No.: B2 Years with Product: - Roof Type: Floating Floor Type: Cone down Internal Floating Roof: None Insulation: None Base: Sand Columns: None Lining: None Mixers: Yes Heaters: None Year Built: - Anodes/CP: None Previous Test Results: N/A Repair Dates: Not known.

Special Notes and Because uncertainty about sludge level sensors placed at 1.5 m above the knuckle. Concerns:

Test Date: 23/10/2000 System+Calib: SP-2000 (Blue) Engineers: A.Engineer Test Temp., °C: 17 deg C Test Level, m: 100 % Sludge Level, m: Unknown Weather: F3/Sunny Settling Time, hrs.: >24 hrs. No.Sensors/Rows/Height: 18/1/1.5 m TANKPAC Test Hits >XdB: 201648>35 dB ASL: 16 Noise/Filter Detail: Wind noise and noise from operators walking around tank.

Hits (TPG) >x dB: 37734>35 dB Filt/JCL Hits >x dB: 1135>35 dB Overall Grade: C Grade Compensation: 0

Recommendations: Composite Grade III

Test Observations: Operators walking around tank.

AE Source Detail : Activity in the central region of the tank floor. (All Data >40 Events)

Concentrated PLD sources: 1 - Grade: 3 Sources 4 - Grade: None 2 - Grade: None 5 - Grade: None 3 - Grade: 1 Source


EXPLANATION AND GLOSSARY OF ABBREVIATIONS.

“Overall Data” :- This is the data due to active corrosion of the tank, plus any leak noise. The data may be evenly spread over the tank or localised, see below: “Potential Leak Data/Sources" :- This (PLD or JCL) is data characteristic of severe localised corrosion damage, graded 1 ("A") (minor) to 5 ("E") (highly active). Not actual leakage, but a future "potential leak” location. “Leak Data” :- If we are fairly sure the tank is actually leaking we will make a statement, “probable leak” to this effect, and if the source is located, give the location. ASL :- This is the Average continuous Signal Level, in the case of very severe leaks being present this will increase (e.g. 1cm hole in Naptha tank ≈ 60dB), typically ASL is in the range of 18 – 20dB. OAL :- Overall % of data located on the floor. This is a location “quality check”, the range is usually between 5 – 30%, meaning that this percentage of emissions detected actually reached three sensors and could be located. For A/B grade tanks it is normal for this to be low as the signals are weak from minor or no corrosion activity. If the % is very low but the Overall tank grade is high this indicates the presence of dense sludge or the possibility of corrosion from the wall instead of the floor. PLL :- The % of “Potential Leak” data located on the floor. This is the same as OAL but applied to the “Potential Leak” data. Overall TANKPAC Grade :- This relates to the overall corrosion damage detected during the test. A – Very Minor/No Damage B – Minor Damage C – Intermediate Damage D – Active Damage E – Highly Active Damage Composite Grade :- This combines the Overall TANKPAC corrosion damage grade with the “Potential Leak” or severe localised damage grade, to produce a final grade with an associated recommendation according to the risk matrix below: "PLD GRADE" 5 III III IV IV IV I – No active damage, re-test in 4/5 years. 4 II III III IV IV II – Minor active damage, re-test in 2 years. 3 II II III III III III – Active damage re-test in max.1 year*. 2 I I II II n/a IV – Very active damage. Re-test in 0.5 year*. None / 1 I I II n/a n/a * or schedule for internal inspection "OVERALL GRADE" ----- A B C D E n/a should not occur at standard test threshold Note: Should a leak be highly probable this will be stated separately, and may influence the grade. This final Composite Grade has been developed by PAL customers from more than 10 years experience and allows simple prioritisation of tanks for internal inspection. Tankpac test hits >xdB :- The total amount of data (including extraneous noise sources) recorded above the test threshold (xdB) during the test. AE hits (TPG) >xdB :- TANKPAC Grading Hits. This shows how much data (excluding noise sources) the tank floor has emitted above the standard test threshold for that size and type of tank. AE filt/JCL Hits >xdB :- “Potential Leak” Hits.This shows the amount of data above the test threshold which is representative of “Potential Leak” data or severe localised damage. Overplating: Repairs by overplating does not stop underside corrosion of the original floor. There is a risk that this may still be detected. When reviewing source activity this should be considered.

tankpac sample report

Documents