New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy...
-
Upload
dangnguyet -
Category
Documents
-
view
228 -
download
2
Transcript of New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy...
![Page 1: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/1.jpg)
New Specification for Internal Liquid
Epoxy Coating Systems For Carbon
Steel Pipes and Line Pipes
Talal Nabhani, Ph.D.
Nasser Behlani, Eng
Ahmed Al-Harthy, Eng.
Johnson Barry, Eng. Petroleum Development Oman
PO Box 81, Postal Code 113
Muscat, Sultanate of Oman
Amal Al-Borno, Ph.D.
Mick Brown, Ph.D. Charter Coating Services (2000) Ltd.
#6, 4604-13 Street N.E.
Calgary, Alberta, Canada T2E 6P1
![Page 2: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/2.jpg)
Project Background –
Internal Pipe Coatings
Problem:
• Shortage of local FBE applicators for Oman
• Projects not being done to schedule
• No documentation for qualification of alternative
coatings
Project:
• Prepare specifications for liquid coating
• Market research liquid coatings
• Identify, source and test candidate coatings
![Page 3: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/3.jpg)
Liquid Coatings vs. FBE
FBE
• base and converter together
• high application
temperatures
• phosphate steel treatment
sometimes recommended
• DSC useful as QC tool
• powder application
equipment required
• typically very fast cure of
coating
• usually very flexible
Liquid Coatings
• base and converter separate
• application temperatures lower
than for FBE
• phosphate treatment not
required
• DSC not such a QC tool
• variable and different
application equipment used
• typically require longer time to
cure coating
• often less flexible than FBE
![Page 4: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/4.jpg)
Operating Conditions
Parameter System 1
(water only) System 2 (Production fluids
containing oil, gas and water)
Design Temp. 85 °C 85 °C
Design Pressure Not Applicable 50 bar
GOR 0 <300
% Water Cut Not Applicable 50%
CO2 Pp Not Applicable (0) 3 bar
H2S Pp Not Applicable (0) 0.5 bar
Solid/Velocity Less than
erosional velocity Less than erosional velocity
Chlorides (Cl-) <100000 ppm <100000 ppm
![Page 5: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/5.jpg)
Market Research for Coatings
• 40 coating companies were contacted
![Page 6: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/6.jpg)
Market Research for Coatings – contd.
• Only 8 suppliers indicated that they had
appropriate coatings
• 10 coatings were proposed
• Study of product data sheets and test data
resulted in elimination of 4 products
• Only 6 products
for initial testing!
From…
![Page 7: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/7.jpg)
Specification - objectives
Specification details to cover:
• define responsibilities of end-user, supplier and
applicator
• qualification procedures for coating and
applicator
• application process details
• QC of materials and equipment
• inspection requirements and procedures
• coating tests for qualification and QC/QA
![Page 8: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/8.jpg)
Qualification of Coatings
• consider factors in service conditions that are most
likely to lead to coating failure
• tests to demonstrate performance ≥ FBE for service
conditions
• develop screening tests to eliminate inappropriate
coatings
• market research available liquid coatings
• identify and source candidate coatings
• develop test program for screening and qualification
• conduct testing to qualify coatings
![Page 9: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/9.jpg)
Qualification Testing
• To ensure good performance and ≥ FBE in the
service conditions, a broad spectrum of tests
were selected
• Tests include destructive and NDT with the latter
particularly suitable for QC on site
• Tests examine properties related to the
application on steel and also coating properties
![Page 10: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/10.jpg)
Physical Properties Tests
• Film Thickness – how evenly was it applied and how
well does it cover the surface?
• Holiday detection – are there holes or cracks in the
coating?
• Hardness – how hard is the coating?
• Porosity – what level of foam is present in the
coating film near the substrate and in cross section?
• Interface contamination – how clean was the steel
surface when the coating was applied?
![Page 11: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/11.jpg)
Physical Performance
• Impact – how well does the coating resist
damage when impacted?
• Flexibility – how well will it cope with bending of
the pipeline?
• Abrasion – how well does the coating resist film
loss when abraded?
• Penetration – how much does the film thickness
reduce under a heavy localized load?
![Page 12: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/12.jpg)
Physical Characteristics
Adhesion and coating integrity:
• Knife adhesion – leverage at base of coating
particularly examines adhesion to substrate.
• Pull-off adhesion – examines adhesive and
cohesive properties of the coating; shows any weak
regions in the coating film.
Note that these tests are also used after immersion
tests to examine for changes in the coating film as
a result of the testing
![Page 13: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/13.jpg)
Physical Characteristics
Barrier properties and effects of heat:
• Water vapour transmission – how good is the
coating as a barrier to the passage of water?
• DSC – is the Tg above the pipeline rated
temperature and does it agree with data sheet?
• Linear thermal expansion – what happens to film
dimensions when the temperature changes and
how does this compare to steel?
![Page 14: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/14.jpg)
Chemical Resistance Tests
• Hot water resistance (85°C) – how well does the
coating retain adhesion when immersed?
• Chemical resistance + autoclave – this test
exposes the coating to different chemicals for 90
days and then exposes the coating to pressure
and high temperature before examining for
blisters, cracks, delamination, or other defects.
![Page 15: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/15.jpg)
Chemical Resistance Tests
• CD (85°C) – how does cathodic protection affect
coating adhesion?
• Water absorption (23 and 85°C) – how much
water will the coating absorb with long-term
immersion?
• Gas pressure variation (10 cycles) – how well
does the coating withstand changes in pressure?
• Salt fog – how well does the coating withstand
high salt environments and how well does it
hinder undercreep?
![Page 16: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/16.jpg)
Screening Tests
• In order to minimize the testing conducted, the
candidate coatings were initially only tested
using selected tests.
• Based on the results in these screening tests
coatings were selected for testing in the
remaining qualification tests.
![Page 17: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/17.jpg)
Screening Tests - Adhesion
Pull-Off Adhesion
0
5
10
15
20
25
30
1 2 3 4 5
Pu
ll-o
ff A
dh
es
ion
MP
a
Coating #
X-Scribe Adhesion
0
0.5
1
1.5
2
1 2 3 4 5 Su
bs
tra
te e
xp
os
ure
(m
m)
Coating #
PASS
PASS
FAIL
FAIL
• All coatings showed very good adhesion to the steel
and passed Specification requirements
![Page 18: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/18.jpg)
Screening Tests - Flexibility
0
0.5
1
1.5
2
2.5
3
1 2 3 4 5
Fle
xib
ilit
y °
/PD
Coating #
PASS
FAIL
• Only Coating 2 passed the test, Coating 5 was next best
and Coating 4 was the least flexible
![Page 19: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/19.jpg)
Screening - Cathodic Disbondment
0
1
2
3
4
5
6
7
8
1 2 3 4 5
Dis
bo
nd
me
nt
(mm
)
Coating #
PASS
FAIL
• Coatings 1, 2 and 3 had severe chemical attack but
Coatings 4 and 5 passed with Coating 5 best
![Page 20: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/20.jpg)
Screening Tests - Autoclave
1 2 3 4 5
Coating #
Gas
Phase
Water
Phase
• Coatings 1,
2, 4, and 5
had excellent
resistance
with no
blisters, no
adhesion
loss, & only
slight color
change.
• Coating 3
blistered in
both phases
![Page 21: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/21.jpg)
Screening Tests - Water Vapor Transmission
0
50
100
150
200
250
Coating 1 Coating 2 Coating 3 Coating 4 Coating 5
WV
T g
m / m
2 /
24
h
Fail
Pass
Test at 85°C
![Page 22: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/22.jpg)
Screening Tests - Water Absorption
0
10
20
30
40
50
60
70
0 5 10 15 20 25 30 35
Wate
r V
ap
or
Tra
nsm
issio
n (
g/m
2)
Days
1 2 3 4 5 PASS
FAIL Coating #
![Page 23: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/23.jpg)
Comparison Table
Test Coating
1
Coating
2
Coating
3
Coating
4
Coating
5
Adhesion
Flexibility
Porosity
CD Test
Autoclave
WVT Water
Absorption
![Page 24: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/24.jpg)
Screening Test Conclusions
• Although all coatings were epoxy novalac based, there were
large differences in performance
• Coatings 4 & 5 were selected for further qualification testing
![Page 25: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/25.jpg)
Coatings 4 &5 Qualification Testing
Additional tests conducted:
• WVT and water absorption extension to 90days
• Hot water resistance: 85°C for 90 days
• Penetration: 85°C
• Impact resistance: 0 and 20°C
• Abrasion resistance: 23°C
• Chemical resistance: 23°C for 90 days
• Autoclave after chemical resistance
• Gas pressure variation: 23°C at 100 bar, 10 cycles
• Salt fog: 35°C for 1000 hours
• DSC
• Linear Thermal Expansion: -10°C to + 90°C
![Page 26: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/26.jpg)
Coatings 4 &5 Qualification Testing
Following are highlights of performance and differences.
Note the following:
• Hot water resistance: both passed well
• Penetration: both passed well
• Gas pressure variation: both passed well
• Salt fog: both passed well
• Other tests are summarized on following slides…
![Page 27: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/27.jpg)
Water vapour transmission (WVT)
WVT = 0.95 gm/m2/24h at 23°C
0
0.05
0.1
0.15
0.2
0.25
0.3
0 20 40 60 80 100
We
igh
t Lo
ss (
gm)
Time (Days)
WVT = 0.22 gm/m2/24h at 23°C
Coating 4
Coating 5
WVT at 23°C
met requirement
of ≤ 3.0 g/m2/24h
At 85°C neither
coating met
requirement but test
vessel could not
handle pressure at
elevated temp.
Pass Fail
![Page 28: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/28.jpg)
Water absorption
0
20
40
60
80
100
120
0 20 40 60 80 100
Wat
er
Ab
sorp
tio
n, g
/m2
Time (Days)
Coating 5 - 23°C
Coating 5 - 85°C
Coating 4 - 23°C
Coating 4 - 85°C Fail
Pass
![Page 29: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/29.jpg)
Impact resistance
Fail 0
2
4
6
8
10
12
14
23C 0C
Imp
act
Str
en
gth
(J) 4 5
Pass
![Page 30: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/30.jpg)
Abrasion resistance
0
20
40
60
80
100
120
Coating 4 Coating 5
Weig
ht
loss m
g/1
000 c
ycle
s
Fail
Pass
![Page 31: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/31.jpg)
Chemical Resistance
Test Media
HCl aq. pH 2.5-3.0
HF aq. pH 2.5-3.0
H2SO4 aq. pH 2.0
NaCl and H2SO4 aq. 100,000 ppm
chlorides pH 3.0
10 % NaCl aq.
Distilled water
Toluene
Autoclave conditions:
• 93ºC, 2000 psi/14MPa
• 50% of sample in 5% NaCl aq.
• Gas: 0.5% H2S, 5% CO2, 94.5% CH4
• 48 Hours
• Rapid decompression at 47oC (after 4 hours
cooling)
Samples were exposed to test media for 90 days and then to
autoclave testing and rating.
Coating 4: no visible degradation to chemicals except surface uniformity in toluene; after
autoclave no adhesion loss but severe colour change and slight surface roughness; also in
toluene F#4 blisters at gas-water interface - PASS
Coating 5: no visible degradation to chemicals or autoclave except severe colour change in
latter and slight adhesion loss in gas phase - PASS
![Page 32: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/32.jpg)
DSC Tests on the samples as received resulted in Tg values NOT ≥ 10°C
above max. operating temp.
BUT additional tests on samples after hot water immersion showed
increases in Tg values
Sample ID Tg (oC)
Coating 5
Sample before hot water test #1 78
#2 78
Sample after hot water test S1 119
S3 117
Sample stored 90 days at 23 oC 100
Coating 4
Sample (before hot water test ) #1 76
#2 77
Sample after hot water test HWR2 92
HWR4 93
Sample stored 90 days at 23oC 79
![Page 33: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/33.jpg)
Coefficient of linear thermal
expansion (CLTE)
0
20
40
60
80
100
120
Steel Coating 4 Coating 5
Avera
ge C
oeff
icie
nt
of
Lin
ear
Th
erm
al
Exp
an
sio
n
(µm
/(m
.oC
))
Av. CLTE -10 to 20°C
Av. CLTE 20 to 90°C
![Page 34: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/34.jpg)
Coatings 4 & 5 Qualification Tests
• Both good BUT did not meet all criteria, differences!
• Both had good hardness, adhesion, and resistance to impact,
penetration, chemicals, hot water, salt fog, autoclave and gas
pressure variation.
• Lower than required Tg but this increased after 85°C
immersion, especially for Coating 4.
• Lower than required abrasion resistance and flexibility.
• Coating 5 more flexible that Coating 4.
• Coating 4 better WVT than Coating 5.
• Coating 5 passed water absorption test but Coating 4 showed
increasing absorption at 85°C up to full 90 days of test.
• Coating 4 had lower CLTE (better = closer to that of steel)
• Coating 4 showed some chemical attack in CD test.
![Page 35: New Specification for Internal Liquid Epoxy Coating … Specification for Internal Liquid Epoxy Coating Systems For Carbon Steel Pipes and Line Pipes Talal Nabhani, Ph.D. Nasser Behlani,](https://reader031.fdocuments.us/reader031/viewer/2022021506/5b02c6687f8b9a2e228b6496/html5/thumbnails/35.jpg)
Conclusions
Both Coatings 4 and 5 showed good performance
in the qualification tests but did not meet all the
specification criteria.
Ultimately based on performance in all the tests it
was decided to include Coating 5 in field trials that
are now starting.