ZENITH CONSULTANTS
38 Dryden road
Loanhead
Midlothian
EH20 9LZ
[email protected]
A Guide to Non
Destructive
Testing of Guy Wires
Introduction:
Zenith Structural Access Solutions offers magnetic, non-destructive testing
of guy wires as part of our comprehensive range of flare stack inspections.
About the instrument:
The instrument used to carry out this survey is an Intron Intros MH20-40
magnetic head. This can successfully determine faults within wires ranging
from
20 and 40mm in diameter which would ordinarily go undetected by a visual
inspection. The head is connected to a data logger, which records the data
in real time.
For manufacturers details, see Appendix iii.
Rigging the Instrument:
The instrument is simply clamped to the wire and pulled up and down the
guy wire in a controlled manner via a pulley system mounted at the upper
support. No proprietary work is required to the guy wire, and no adverse
stresses or strains are imposed onto it.
How it’s done:
The survey involves attaching the magnetic head onto the wire, and running it
up and down the wire to magnetise it. Once the wire is magnetised, the
magnetic head is run up and down a further time to gather the required data,
which is stored onto the data logger.
The stored information is then downloaded, and analysed using wintros
software. By analysing the graphical output from the wintros software,
localised faults (LF) and/or metallic loss of area (LMA) can be identified.
For full instructions, see appendix ii.
What it tells us:
These inspections aim to locate the LF’s and LMA’s, and to determine
their severity / magnitude.
LF (localised fault): Detects the presence of a broken/defective wire(s),
or discontinuity in the rope.
LMA (loss of metallic area): Detects loss of sectional area, highlighting possible
loss of capacity.
What is produced:
A detailed report showing the likely locations and suggested severity of faults
along the length of each wire.
For sample report, see Appendix i.
Appendices:
i – Sample Report
ii – Instructions for Use
iii – Manufacturers Brochure
Appendix i- Sample Report
ZENIT
TH CONSU
ULTANTS
Unit 7 Dryden Vale Bilstton Glen Industrial Estate Lo
oanhead
Midl othian EH
H20 9HN
enquiries@
e
@zenithsttructural.c
com
XXXXXX
X
XXXXXXX
XX Inspec
ction Repo
ort
Revision
nC
Survey Engineer…
……………
……………D
David Kellyy
ed By: .......................................J
John Lambb
Prepare
August 20
014
Docume
ent Revisio
on Status
Rev
v Details
Dated
Status
s
C
Add com
mparison Ta
ables
13/10
C
Autho
or
CC
Checked
SC
SECTION 1 - INTRODUCTION
1.0
INTRODUCTION
1.1 In August 2014 Zenith Consultants were engaged by XXXXXX to
undertake a survey of the 36-S500B flare stack. The survey was
carried out on 03rd & 04th August 2014 during the KG TAR
shutdown.The report is best read in conjunction with Appendix ‘A’,
‘B’ & ‘C’
1.2 The purpose of the survey was to identify and record any defects to
the guy wires and termination connections to the flare and to make
recommendations for future repair.
SECTION 2 – DESCRIPTION OF STRUCTURE
2.0
DESCRIPTION
2.1 The flare is 90m high from ground level guyed structure, with 3No
anchor blocks located at 120 degrees. Each anchor block has four
guy wires supporting the flare.
2.2 The flare has a fixed ladder and staged gantries over the
height.
SECTION 3 - PROCEDURES AND METHODS
3.0
PROCEDURES AND METHODS
3.1 Access to the head of the flare was achieved using the fixed
ladder/gantry arrangement.
3.2 A visual examination of all external parts.
3.3 The Magnetic Inspection was carried out on each guy wire.
3.4 The inspection was carried out using an Intron Magnetic head 2040 with Wintros software for assessment of the results. The
apparatus uses LMA (loss of metallic area) and LF (local fault)
readings to assess the condition of the cable.
3.5 The first section of cable was first magnetised and then used to
calibrate the equipment.
3,6 The inspection was carried out using a hoisting arrangement.
3.7 The cable was first magnetised before two inspections were
carried out.
SECTION 4 - SURVEY RESULTS
4.0
SURVEY RESULTS
4.1 Ground Termination Bases:
No evidence of distress to the concrete pile block or soil surrounds.
4.2 Ground Termination Anchors:
No evidence of corrosion, distortion or separation from the concrete
pile.
4.3 Ground Termination Eyelets and Pins:
No evidence of excessive wear,
4.4 Ground Termination Rope Shackles:
Shackles appear in good condition and showing no signs of
corrosion.
4.5 Ground Termination Turnbuckle:
Turnbuckle is in good condition, is fully operational and secure.
70% of adjustment in the turnbuckle is currently in use.
4.5 Stack Termination eyelet arrangement:
Good condition, no chaffing or wear.
4.6 Stack Termination Shackle:
Good condition.
4.7 Stack Termination Lug:
Good condition, no evidence of weld fractures.
4.8 Guy Wire Inspection:
Guy wires are in generally good condition, there are however a
number of broken wires within some of the cables, but the small
number of breaks will have no effect on the stability of the flare.
Loss of the metallic coat on the wires over localized areas is evident
from the survey data. Refer to Appendix A, B & C for survey results
of the guy wires.
Verticality & Rope Tension
4.9 The results of the verticality and rope tension are appended
(Appendix D).
4.10 The tension figures in the lower ropes are generally in line with pretension design figures. The recorded information does not reflect the
tension values obtained in the previous year’s measurements, the
recorded information for this year is consistently higher than the
2009 readings.
4.11 The variation in readings could be due a variation in site wind speed,
wind direction, gusting, site temperature, operating temperature etc.
If the site variables are low during one survey, a relatively modest
increase of the variables in the next survey could result in a threefold
increase in load.
4.12 In the absence of the original calculations Zenith have adopted a
comparison against of the tension figures suggested by ‘Guydes’,
(Guydes being one of the leading software packages for the design
of guyed stacks).
4.13 For the purpose of comparison, good practice suggests guy stacks
are typically set at pretension of only 6% to 12% of the breaking
strength due to the hot gases flowing into the stacks.
4.14 The ropes are within these guidelines but remain marginally over
tensioned when compared to the pre-tension design data on record.
It would be normal practice to only tension ropes rather than slacken
ropes in a scenario where the towers have performed with out fault
and show no sign of distress.
4.15 In conclusion the ropes would be re-examined within 12 months
recording all tolerances at site level including temperature and wind
speed.
4.16 The verticality of the structure is marginally out with tolerance in the
lower two positions. No correction has been made at this time
based on the upper levels of the flare stack being within tolerance.
It was determined that any adjustment at this stage would
compromise the overall results and therefore no action undertaken.
SECTION 5 - DISCUSSION AND RECOMMENDATIONS
5.0
DISCUSSION AND RECOMMENDATIONS
5.1 The flare guy wires and termination points should be inspected
at regular intervals.
5.2 The flare remains serviceable under current operating conditions.
5.3
The flare guy wires are in serviceable condition and should be
re-inspected during the next shutdown in 2014.
5.4 Although there are localized areas where the metal coat to the wire
has thinned or has been removed, there is no requirement for any
repair work to be carried out at this time.
5.5 A magnetic inspection should be carried out at the next shut down in
2016. The result of which should be read alongside this survey to
give a rate of deterioration of the wires.
5.6 Zenith remain satisfied that the guy ropes and the flare stacks are
operating within tolerance as the thermal expansion due to hot gases
in this instance is limited to the tip of the stack and not throughout
the full length hence the tension in the wires can approach the
20% to
5.7 40% generally used for transmission towers restrained by guys.
5.8 The verticality of the tower should be checked at regular intervals
(not exceeding 12 months) and where tension has relaxed every
effort made to correct the verticality to within the BSEN standards
without compromising the overall tolerances.
SECTION 6 – APPENDICES
APPENDICES
ABCDE-
Elevation ‘A’ guy wires
Elevation ‘B’ guy wires
Elevation ‘C’ guy wires
Verticality & Rope Tension
Comparison Tables
APPENDIX A- ELEVATION 'A' GUY WIRES
LF trace, mV
16.0
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0
-2.0
-4.0
-6.0
-8.0
-10.0
-12.0
-14.0
-16.0
-18.0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
165
170
175
180
185
190
195
LF trace, mV
20.0
15.0
10.0
5.0
0.0
-5.0
-10.0
-15.0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
LF trace, mV
20.0
15.0
10.0
5.0
0.0
-5.0
-10.0
-15.0
-20.0
-25.0
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
LF trace, mV
20.0
15.0
10.0
5.0
0.0
-5.0
-10.0
-15.0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
APPENDIX B - ELEVATION '8' GUY WIRES
LF trace, mV
16.0
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0
-2.0
-4.0
-6.0
-8.0
-10.0
-12.0
-14.0
-16.0
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
165
170
175
180
185
190
LF trace, mV
10.0
5.0
0.0
-5.0
-10.0
-15.0
-20.0
-25.0
-30.0
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
LF trace, mV
20.0
15.0
10.0
5.0
0.0
-5.0
-10.0
-15.0
-20.0
-25.0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
LF trace, mV
6.0
4.0
2.0
0.0
-2.0
-4.0
-6.0
-8.0
-10.0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
60
62
64
66
68
70
72
74
76
78
80
82
84
86
88
90
92
94
96
98
APPENDIX C – ELEVATION C GUY WIRES
LF trace, mV
25.0
20.0
15.0
10.0
5.0
0.0
-5.0
-10.0
-15.0
-20.0
-25.0
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
165
170
175
180
185
190
LF trace, mV
40.0
35.0
30.0
25.0
20.0
15.0
10.0
5.0
0.0
-5.0
-10.0
-15.0
-20.0
-25.0
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
LF trace, mV
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0
-2.0
-4.0
-6.0
-8.0
-10.0
-12.0
-14.0
0
LF trace, mV
10.0
8.0
6.0
4.0
2.0
0.0
-2.0
-4.0
-6.0
-8.0
-10.0
-12.0
-14.0
-16.0
-18.0
-20.0
0
2
5
4
10
6
8
15
10
12
20
14
16
25
18
20
30
22
24
35
26
28
40
30
32
45
34
50
36
38
55
40
42
60
44
46
65
48
50
70
52
54
75
56
58
80
60
62
85
64
66
90
68
70
95
72
74
100
76
78
105
80
82
110
84
86
115
88
90
120
92
94
125
96
98
APPENDIX D - VERTICALITY AND ROPE TENSION
APPENDIX 'E' - COMPARISON TABLES
Ineos Manufactuing (Scotland) Ltd
Flare B 36‐S‐500‐B
Client
Structure
1
2
3
4
5
6
1 (Lower)
2
3
4 (Upper)
Height
mm
20000
45000
72000
88000
D1
mm
65
60
50
45
D2
mm
6
52
22
2
Resultant
Max. Allowable
mm
Total MM2
MM
20
4261
65
45
6304
79
72
2984
55
88
2029
45
0
0
0
0
0
0
Result
FALSE
FALSE
OK
OK
FALSE
FALSE
* D1 = Direction 1, D2 = Direction 2
Readings are based on 'Latch & Batchelor' Steel Wire Ropes Booklet for General Purpose Ropes to BSEN12385‐4 2002 with a Steel Core Grade 1770 N/MM2 and should only be used as a guide.
Where a direct comparsion can not be made the reading (i.e dia/construction) the next lower performing wire should be used.
Comparison with the original design / construction should be completed, wherever practical.
Rope No
Position
Diameter
Measured Load (Kn)
Theoretical MBL (Kn)
% of MBL
1
A
24
75.5
363
20.80
B
24
76.55
363
21.09
C
24
68.75
363
18.94
A
28
45.02
494
9.11
B
28
47.1
494
9.53
2
3
C
28
46.6
494
9.43
A
34
71.5
645
11.09
B
34
66.6
645
10.33
C
34
59.58
645
9.24
A
32
41.35
645
6.41
B
32
43.4
645
6.73
C
32
41.35
645
6.41
Rope Type
6X19, 6X36, 6X41
6X19, 6X36, 6X42
6X19, 6X36, 6X43
6X19, 6X36, 6X44
6X19, 6X36, 6X45
6X19, 6X36, 6X46
6X19, 6X36, 6X47
6X19, 6X36, 6X48
6X19, 6X36, 6X49
6X19, 6X36, 6X50
6X19, 6X36, 6X51
6X19, 6X36, 6X52
6X19, 6X36, 6X53
6X19, 6X36, 6X54
6X19, 6X36, 6X55
6X19, 6X36, 6X56
6X19, 6X36, 6X57
6X19, 6X36, 6X58
MBL
Kn
204
227
252
305
363
426
494
645
772
817
910
1008
1220
1453
1704
1837
1976
2268
MBL
t
20.8
23.1
25.7
31.1
37.0
43.4
50.4
65.7
78.7
83.3
92.8
102.8
124.4
148.1
173.7
187.3
201.4
231.2
4
Cross Check Information
Dia
MM
18
19
20
22
24
26
28
32
35
36
38
40
44
48
52
54
56
60
6%
Lower Theoretical
Kn
t
12.24
1.25
13.62
1.39
15.12
1.54
18.30
1.87
21.78
2.22
25.56
2.61
29.64
3.02
38.70
3.94
46.32
4.72
49.02
5.00
54.60
5.57
60.48
6.17
73.20
7.46
87.18
8.89
102.24
10.42
110.22
11.24
118.56
12.09
136.08
13.87
9%
Average Theoretical
Kn
t
18.36
1.87
20.43
2.08
22.68
2.31
27.45
2.80
32.67
3.33
38.34
3.91
44.46
4.53
58.05
5.92
69.48
7.08
73.53
7.50
81.90
8.35
90.72
9.25
109.80
11.19
130.77
13.33
153.36
15.63
165.33
16.85
177.84
18.13
204.12
20.81
12%
Upper Theoretical
Kn
t
24.48
2.50
27.24
2.78
30.24
3.08
36.60
3.73
43.56
4.44
51.12
5.21
59.28
6.04
77.40
7.89
92.64
9.44
98.04
9.99
109.20
11.13
120.96
12.33
146.40
14.92
174.36
17.77
204.48
20.84
220.44
22.47
237.12
24.17
272.16
27.74
20%
Cold Structure
Kn
t
40.80
4.16
45.40
4.63
50.40
5.14
61.00
6.22
72.60
7.40
85.20
8.69
98.80
10.07
129.00
13.15
154.40
15.74
163.40
16.66
182.00
18.55
201.60
20.55
244.00
24.87
290.60
29.62
340.80
34.74
367.40
37.45
395.20
40.29
453.60
46.24
40%
Upper Limit
Kn
t
81.60
8.32
90.80
9.26
100.80
10.28
122.00
12.44
145.20
14.80
170.40
17.37
197.60
20.14
258.00
26.30
308.80
31.48
326.80
33.31
364.00
37.10
403.20
41.10
488.00
49.75
581.20
59.25
681.60
69.48
734.80
74.90
790.40
80.57
907.20
92.48
Appendix ii -Instructions for Use
Appendix iii- Manufacturers Brochure