50 0 9MB
PRACTICAL WORKSHOP
FROSIO TRAINING BODY HARVISH TECHNICAL SERVICES No:5, Vellalar Street, 3 rd Main Road, Ambattur Industrial Estate, Chennai-600058, Tamilnadu, India Mobile: +91-9176618930 Email: [email protected]
FROSIO PRACTICAL EXAMINATION (PRACTICE MODULE)
STATION-1
AMBIENT CONDITIONS Sling Psychrometer:
Using Psychrometer to Measure Ambient Conditions
The most common (and most economical) method of measuring
the am bient conditions on a project site is by using either a sling or battery-powered psychrometer, in conjunction with the US Weather Bureau Psychometric Tables. The psychrometer is used to measure the air temperature and to assess the latent heat loss caused by water evaporation from a wetted sock on the end of a bulb thermometer. The psychometric tables are used to look-up the relative humidity and dew point temperature (based upon temperature readings from the psychrometer and the barometric pressure). For now, it is more
important that we know how to obtain the information. We will discuss what the information means later
in the module. Obtaining Temperature Psychrometer
Readings
from
the
Sling and the battery-powered psychrometer are each equipped
with two bulb thermometers. The two thermometers are identical, except that one has a wick or sock covering the end of the bulb. This thermometer is called the wet bulb. The thermometer without the wick is called the dry bulb thermometer. Follow Steps 1 through 4 below to obtain the dry bulb and wet bulb temperatures. Step 1: Verify wick cleanliness Prior to each use, verify that the wick surrounding the wet bulb thermometer is relatively clean. If the wick is dirty, the pores of the wick may be clogged, which can prevent proper contact of the water with the thermometer bulb. Wick or sock Step 2: Saturate the wick Saturate the wick with clean water, or fill the water reservoir at the end of the sling
ps y chrom eter . You m ay
us e dis tilled or deionized water, but this is usually not necessary. In fact, it is more important that the wick remain clean, than it is to use purified water.
Step 3: Obtain the wet bulb temperature If you are using a sling psychrometer, whirl the instrument through the
air ( aw ay from y our body ) fo r approximately 20 or 30 seconds. Be careful not to “whip” the instrument through the air, but whirl the gage at a moderate speed, such
that
the am bient air pas ses ov er both bulb therm om eters . After 20 or 30 seconds, obtain a reading from only the wet bulb thermometer. Remember or write down this temperature. Without re wetting the wick, whirl the instrument for another 20 or 30 seconds and obtain another temperature reading from the wet bulb thermometer. Repeat this process until two consecutive readings of the wet bulb are within 0.5° of one another. Record the wet bulb temperature after it stabilizes. Step 4: Obtain the dry bulb temperature Independent of whether you are using a sling or batterypowered psychrometer, the dry bulb temperature is read directly from the bulb without the wick on the end. This temperature stabilizes rather quickly, and only needs to be read one time (after the wet bulb temperature stabilizes).
Steel Thermometer
Dial type surface temperature thermometers contain a bi-metallic, temperature-sensing spring on the back of the thermometer that expands and contracts with the temperature of the surface. Since the spring is attached to the indicator needle on the front side of the thermometer, the needle increases and decreases on the temperature scale, indicating the surface temperature. Magnets attached to the back of the thermometer enable self-attachment to vertical steel surfaces, although this thermometer can be used on almost any surface. Measuring surface thermometers
temperature
using
dial
type
Step 1: Place the thermometer in the desired location. Surface temperature can vary considerably and should be measured in the area where surface preparation and/or painting work is scheduled to take place. In some cases, multiple readings are required to assess the range of surface temperature in a given area. Step 2: Allow the thermometer to remain undisturbed for at least 3 minutes before recording the temperature. Lightly tap the face glass before reading the dial, and make sure to read
the thermometer dial straight on to eliminate a misread due to parallax. Dew point Calculator
Dew point Calculator provides accurate values of Dew point and Relative Humidity (RH) from the wet and dry bulb temperatures measured by a Whirling or Sling Hygrometer. Use of the IX diagram On the left-hand side of the diagram you will find the horizontal lines for the dry bulb temperature. On the righthand side, the lines coming up at a 45° angle are the wet bulb temperatures. At the point of intersection between a read dry bulb temperature and wet bulb temperature, you will find the relative humidity.
Example: You have determined the following conditions using the slinghygrometer: Wet bulb temperature (WBT): 20 °C Dry bulb temperature (DBT): 24 °C Determine the relative humidity, RH and the Dew point temperature (DPT). The relative humidity can be determined at the intersection point of the DBT and WBT. Here the DBT= 24 °C and WBT = 20 °C, the intersection point, presents RH= 70 %. As you already know, when lowering the temperature, the humidity increases. Since the Dew point temperature is the temperature where the RH is JOO%, we must try to locate the temperature where air at (24 °C and 70 %RH) has been cooled to condensation. We find this going vertically down from the initial condition (24 °C and 70 %RH) to the saturation line (100 % RH). Here the dew point temperature can be read, DPT= 18 °C
IX-diagram
IX-Diagram °
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nehill kg/
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kg, moistu re cont ent lbs/lb O 020 o,91�
0 0,01
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0,025 I
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,, '' ,;,
' ,,. ' .... I'- I
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STATION - 2
INSPECTION OF THE SUBSTRATES
ISO Surface Cleanliness Standards ISO standard 8501-1:
Two degrees of Hand & Power Tool Cleaning (St 2 & 3)
Four degrees of Abrasive blasting Cleaning (Sa1, Sa2, Sa2.5 & Sa3) One degree of Flame cleaning (F1)
Assessing Surface Cleanliness
Grade
A: Steel surface largely covered with adhering mill scale but little, if any rust
Grade B: Steel surface, which has begun to rust, and from which the mill scale has begun to flake Grade
C: Steel surface on which the mill scale has rusted away or from which it can be scraped, but with slight pitting visible under normal vision.
Grade
D: Steel surface on which the mill scale has rusted away and on which general pitting is visible under normal vision
Standard notation usually, but not always, includes the original condition of steel before blasting i.e. “B Sa3”. Pictorial
standards of cleanliness (Sa1, Sa2, Sa2.5 and Sa3) are depicted overleaf.
ISO 8501-1 Select “BEFORE” photo of Initial surface condition - A, B, C, D Determine level of Cleanliness required by specification - St2, St3, Sa1, Sa2, Sa2 ½, Sa3 Select “AFTER” photo -e.g. B Sa2 ISO St2: Thorough Hand and Power Tool Cleaning “When viewed without magnification, the surface shall be free from visible oil, grease and dirt, and poorly adhering mill scale, rust, paint coatings and foreign matter.” ISO St2: Very Thorough Hand and Power Tool Cleaning “(Same) as for St2, but the surface shall be treated much more thoroughly to give a metallic sheen arising from the metallic substrate.” Assessing Surface Cleanliness
ISO Sa 2 ½ The Images in ISO guides rarely “match” actual conditions. Establish a project specific surface cleanliness standard/test section Use ISO 8501-1 visual guides to “calibrate” the eye Preserve with clear sealer or photograph
Blast-cleaning to Sa Standards Blast cleaning to ISO 8501-1 Sa standards is a commonly used specification with pictorial and written guidelines as follows:
Sa 1
Sa2.5
Sa2
Sa3
STATION - 3
ISO Visual Comparators Grit or Shot prepared surfaces Used with 5-10X magnifier Surface roughness “graded” as Fine Medium Coarse Grit comparator
ISO Comparator
G
Comparator with surface profiles corresponding to (or simulating) surfaces obtained by abrasive blast- cleaning with metallic or mineral grit Shot comparator
ISO Comparator
S
Comparator with surface profiles corresponding to (or simulating) surfaces obtained by abrasive blast- cleaning with metallic shot Using 8503-1 for determining roughness The comparator is placed onto the surface of the blast-cleaned steel. The surface profile is seen through the center of the comparator and in turn compared with the segments of the comparator. In accordance with ISO 8503-1 the roughness is characterized as fine, medium or coarse. If you find it difficult to make the comparison, a 7 X magnifying glass can be used. Avoid using the fingertip for control, as it may leave traces of grease and salts on the surface.
The ISO comparators are widely used. But also other methods for checking the roughness are available.
Table 1 — Nominal values and tolerances for the surface profiles of the segments of ISO surface profile comparators ISO comparators for steel, blast-cleaned with grit abrasives Segment 1
a
Nominal reading
μm
25
Tolerance μm 3
2
60
10
3
100
15
4
150
20
ISO comparators for steel, blast-cleaned with shot abrasives
Segment 1
a
Nominal reading
μm
25
Tolerance μm 3
2
40
5
3
70
10
4
100
15
Where using the microscope method (see ISO 8503-3), the nominal reading refers to hy. Where using the stylus method (see ISO 8503-4), the nominal reading refers to Ry5. Each ISO comparator shall be accompanied by a calibration certificate stating the method for determining the surface profile, the estimated tolerance and the calibrated surface profile, in micrometers, of each segment.
Table-2 - Limits of Profile Grades
ISO comparators for steel, blast-cleaned with grit abrasives Profiles equal to segment 1 and up to Fine (G)
but excluding segment 2
Medium (G) Profiles equal to segment 2 and up to but excluding segment 3 Coarse (G)
Profiles equal to segment 3 and up to but excluding segment 4
ISO comparators for steel, blast-cleaned with shot abrasives Profiles equal to segment 1 and up to Fine (S)
but excluding segment 2
Medium (S) Profiles equal to segment 2 and up to but excluding segment 3 Coarse (S)
Profiles equal to segment 3 and up to but excluding segment 4
STATION - 4
PAINT INSPECTION GAUGE (PIG GAUGE) MICROSCOPE WITH SCALE
MEASURING FILM THICKNESS 1.
2. 3.
Mark the surface to be tested with a stroke of the black marker pen provided with your gauge. Note that there should always be a distinct contrast between the colour of the pen ink and the coating; different pen ink colours may therefore be required for dark coatings. Fit/select the appropriate cutting tool Cut the coating at right-angles to the pen mark as follows:
Place the gauge on the specimen with both guidance wheels in contact with the surface of the specimen (this ensures that the knife blade produces an exact vertical cut with no tilting to one side). Pull the gauge towards you and apply a little pressure. Slight pressure is normally sufficient to penetrate through to the substrate. Heavier pressure may be required for very thick coatings and very hard surfaces.
4.
Position the gauge vertically so that the microscope
5. 6. 7.
8.
lens is over the cut. Press and hold the light switch to illuminate the cut. Look through the microscope lens and rotate the focus adjuster until the cut is visible clearly. Rotate the graticule scale until it is at right angles to the cut and the scale divisions are parallel to the cut. Note that one side of the cut will have a straight edge and the other side is likely to be ragged. Measure the width of the cut coating (or coatings) by counting the number of graticule divisions. To convert the width of the cut coating into coating thickness, either:
Multiply the number of graticule divisions by the graticule scale factor shown in Table 1. Table 1: Graticule Scale Factor Cutting
Practical Maximum thickness
Cutting
Graticule scale factor
Tool#
(μm)
(Mils)
angle
Mm scale (μm)
Inch scale (mils)
1 4 6
1600 800 160
64 32 6.4
45° 26.6° 5.7°
20 10 2
1 0.5 0.1
a. Based on using 80% of cutter width
In the example shown overleaf, the coating thickness using cutting tool #4 is: 42 divisions x 10μm per division = 420μm or;
33 divisions x 0.5mils per division = 16.5mils
Or alternatively, calculate the coating thickness using the Table 2, “Additions Table,” on page 9. In the example shown, the coating thickness using cutting tool #4 is:
42 divisions= 40 divisions; 400μm plus 2 divisions 20μm = 420μm
33 divisions = 30 divisions; 15mils plus 3 divisions; 1.5mils = 16.5mils
STATION - 5
DETERMINATION OF WATER SOLUBLE SALTS
Specific Ion (Salt-specific) Chloride Sulfate Ferrous Ion Conductivity (non salt-specific) ISO 8502-9 Specification may prescribe methods of sample retrieval and analysis. Retrieval methods include: Swabbing Latex patches Latex sleeves
Methods of analysis include: Chloride strips and tubes Drop titration for chloride Ferrous ion strips Conductivity meter (non ion-specific) Turbidity meter (sulfate)
Latex Patch/Cell Sample Retrieval Steps
Adhesive patch, the body of which is made of ageing-
resistant, flexible material with closed pores, e.g. polyethylene foam, and with a hole punched in the center. The punched-out material is kept in the hole as reinforcement until the patch is used. One side of the patch is coated with a thin elastomer film. The other side is coated with adhesive and covered by a removable protective sheet made of paper. NOTE: The hole and the outer edge of the patch may be any shape, e.g. circular, rectangular, elliptical, etc. The thickness of the patch shall be 1,5 mm ± 0,3 mm. The width of the adhesive rim between the hole and the outer edge of the patch shall be at least 5 mm. Reusable syringe: max. cylinder volume: 8 ml
max. needle diameter: 1 mm max. needle length: 50 mm
Solvent, chosen as a function of the surface contaminants to be determined. For the determination of water-soluble salts or other water-soluble contaminants, use distilled or deionized water. Procedure for Salt Extraction (ISO 8502-6) 1. Take an adhesive patch of a suitable size. Remove the protective paper and the punched-out material. 2. Press the adhesive side of the patch against the test surface in such a way that the minimum amount of air is trapped in the compartment in the patch. 3. Fill the syringe with solvent.
4. Insert the syringe needle at an angle of about 30° to the
test surface near the outer edge of the patch, so that it passes through the adhesive foam body of the patch into the compartment formed between the elastomer film and the test surface. If the patch is in a position, which makes access to the patch compartment difficult, bend the syringe needle as required. 5. Inject the solvent, ensuring that it wets the whole of the test surface. If necessary to avoid air remaining trapped in the patch compartment, carry out the injection in two steps as follows: Inject half of the solvent. Evacuate the air through the needle by reverse operation of the syringe. Remove the needle from the patch. Holding the syringe with the needle pointing upwards, expel the air. Re-insert the needle into the compartment and inject the remainder of the solvent. 6. After a suitable period of time, to be agreed between the interested parties, suck the solvent back into the syringe. During this period of time, without removing the syringe needle from the patch, re-inject the solvent into the compartment and then suck the solvent back into the syringe cylinder at least four times.
NOTE On unpitted blast- cleaned areas, a period of 10 min has been found satisfactory, as by then more than 90 % of the soluble salts have usually been dissolved. 7. Transfer the solvent to a suitable vessel for analysis. 8. During steps 3 to 7, it is essential that no solvent be lost from the patch or syringe, due for instance to inferiorquality materials or improper handling of the materials. If any solvent is lost, the solution obtained shall be rejected. 9. On completion of step 7, clean and rinse the syringe so that it can be re-used. A bent needle is best left as it is
until it becomes necessary to straighten it or bend it further. Test report The test report shall contain at least the following information: a) A reference to this part of ISO 8502 (i.e. ISO 8502-6);
b) The solvent used;
c) The volume of solvent injected;
d) The total time of contact between the solvent and substrate, i.e. the time agreed in 6 multiplied by the total number of cycles carried out;
e) The temperature during steps 3 to 7 of the procedure;
f) The manufacturer's batch number of the patch used;
g) The date of the test.
Procedure for Salt Analysis (ISO 8502-9) Preparation of water and blank test Pour into the beaker an amount of water that is just large enough for the operation of the conductometer. Usually a volume between 10 ml and 20 ml is needed. To prevent foreign matter inside the beaker and syringe, and on the conductometer probe, from influencing the result, carry out the following blank test. Completely fill the syringe with water from the beaker. Then empty the syringe back into the beaker. Immerse the electrodes of the conductometer fully in the water in the beaker and agitate gently. Record the conductivity (γ1) and the units in which it is expressed, for
example μS/cm. Removal of salts from the steel surface. Follow the procedure specified in clause 5 of ISO 8502 -6:1995, subject to the following specific requirements. Fill the syringe with about one-quarter of the water contained in the beaker.
After 1 min, suck the water back into the syringe cylinder (see 5.6 of ISO 8502-6:1995). Without removing the syringe needle from the patch, re-inject the water into the patch compartment and then suck the water back into the syringe cylinder. Repeat until 10 cycles of injection and sucking have been completed (see 5.7 of ISO 8502-6:1995). At the end of the 10th cycle, retrieve as much as possible of the water from the patch compartment and transfer to the beaker, thus restoring its content to nearly the original volume in (see 5.8 of 8502-6:1995). Conductometric measurement Immerse the electrodes of the conductometer fully in the now contaminated water in the beaker, and record the conductivity (γ2) expressed in the same units as μS/cm. Expression of results The total surface density
ρA
of the salts is given by the
equation: ρA = m A Where m is the mass of salts dissolved from that part of the surface, which is covered by the patch compartment
A
is the area of that part of the
surface. In this case, m is given by
m = c. V.
γ
Where
c is an empirical constant approximately equal to 5 kgm
–
2 –1
S
V is the original volume of water in the beaker
γ
is the change in conductivity, i.e. the difference between the conductivity measured in (Υ2) and the conductivity measured in (Υ1).
STATION - 6
DETERMINATION OF DFT Type 2 - Electronic Gages
“Electronic circuitry converts reference signal to coating thickness” Calibration & Verification of Accuracy Calibration Verification of Accuracy Adjustment Steps are required to be completed before coating thickness data acquisition to determine conformance to a specification
Gage Calibration Performed by the gage manufacture or qualified laboratory Certificate of calibration traceable to a National Metrology Institute required
No standard calibration interval (established based on experience & work environment) One year interval is common Verification of Type 2 Gage Accuracy Verify accuracy per manufacturer instructions (use Traceable Standards) Verification can be done “beginning and end of each work shift (minimum)” During (e.g., hourly), if: Obtaining a large no. Of readings Gage is dropped or readings are suspect Record • Serial no. of gage and standard • Stated & measured thickness Single Point Verification Select one reference test block representing the mid-range of the anticipated coating thickness E.g., 4-6mils (100-150 microns), select 5 mil (125 microns) reference standard Two Point Verification Select a reference test block below and above the median anticipated coating thickness E.g. 5 mils (125 microns), select 3 mils (75microns) and 7 mil (175microns) reference standards Adjustment of Type 2 Gages Aligning a gage’s thickness readings to those of a known thickness value to improve gage accuracy on a specific surface or within a measuring range
Corrects for Surface roughness Substrate Properties Curvature Etc.,
Follow the gage manufacturers step-by-step procedure for gage adjustments Instructions vary by gage manufacturer Adjustment is typically performed using plastic shims (foils) of known thickness Verification in accordance with ISO 19840 Table 1 — Sampling plan
Area/length of inspection area
2
m
Maximum number of measurements allowed to be repeated
(see 6.3 as per ISO
Minimum number of measurements
or m
up to 1
5
19840) 1
above 1 to 3
10
2
above 3 to 10
15
3
above 10 to 30
20
4
above 30 to 100
30
6
above 100
add 10 for every
a
additional 100 m or 100 m or part
2
20 % of the minimum number of measurements
thereof
a
2
Areas above 1 000 m
or m should be divided into smaller inspection areas.
Adjustment of the instrument Before use, it shall be ascertained that the instrument is in good working condition and correctly adjusted. Verification shall then be carried out on uncoated test plates at zero and with verified foils/shims above and below the specified dryfilm thickness. Pre-coated test plates may be used instead of verified foils/shims. If the result of the verification is outside the range given by the manufacturer, the instrument shall not be used. NOTE: the user in most cases carries out Adjustment. Calibration, on the other hand, is the process of setting and recording the thickness values displayed on a dry-film thickness gauge to known values of thickness across the range of the gauge. The gauge manufacturer using traceable thickness standards in most cases carries out calibration. 6.3 Measurement Measurements on the dry film shall only be taken after instrument accuracy has been checked in accordance with. The measurement instrument shall then be used in accordance with the instrument manufacturer’s instructions. Following completion of a series of measurements, and preferably during the measurements, the adjustment of the instrument shall be re-verified. If this is not in accordance with, the results of the measurements shall be rejected. When, during a series of measurements, an individual dry-film thickness value does not meet a criterion and, a repeated measurement not more than 10 mm from the point of the first measurement shall be carried out. The first value shall then be rejected and replaced by the result of the repeated measurement. This new measurement will then be the individual dry-film thickness. If this individual dry-film
thickness does not meet the criterion, it shall not be replaced. For maximum numbers of repeated measurements within an inspection area see Table 1. The number of replaced measurements shall be indicated in the test report. The sampling plan shall be completed even if values do not meet the criteria, unless otherwise agreed. Correction values If the surface profile is known and conforms to ISO 8503-1, correction values given in Table 2 shall be used. Table 2 — Correction values Surface profile Correction in accordance value with ISO 85031 μm Fine
10
Medium
25
Coarse
40
The specification/contract might require the determination of a specific correction value that is a correction value determined on the abrasive blast-cleaned or otherwise roughened substrate with the particular dry-film thickness instrument being used. In this case, the correction value shall be determined in accordance with Annex D. If the surface profile is not known and an uncoated sample is not available, a correction value of 25 μm shall be used. If a sample showing the surface profile is available and the
profile is not in accordance with ISO 8503-1, the correction value shall be determined in accordance with Annex D. If a correction value is used, it shall be subtracted from the individual reading to give the individual dry-film thickness in micrometers. NOTE 1: The correction value is applied once to every reading, no matter if the coating consists of a single layer or multiple layers (see illustration in Figure 1). NOTE 2: For deviating surface profiles or in the case of particular agreements between the interested parties, a method for determining the correction value to be used is given in Annex D. Annex D (normative) Determination of a specific correction value When a specific correction value is to be determined, proceed as follows: Adjust the instrument in accordance with the manufacturer’s instructions. Check the adjustment for intermediate values following the manufacturer’s specification. Use the adjusted instrument on the blast-cleaned or otherwise roughened surface to check a measured foil/shim of approximately 125 μm thickness (but not less than 115 μm or greater than 160 μm). Using the foil/shim, take 10 measurements at different points on the blast-cleaned or otherwise roughened surface and determine the arithmetic mean value. From the mean value, subtract the known value of the foil thickness. The value obtained is the correction value.
Acceptance/rejection criteria For the acceptance of an inspection area, the following criteria shall be fulfilled:
a) The arithmetic mean of all the individual dry-film thicknesses shall be equal to or greater than the nominal dry-film thickness (NDFT);
b)
All individual dry-film thicknesses shall be equal to or above 80 % of the NDFT;
c)
Individual dry-film thicknesses between 80 % of the NDFT and the NDFT are acceptable provided that the number of these measurements is less than 20 % of the total number of individual measurements taken;
d) All individual dry-film thicknesses shall be less than or equal to the specified maximum dry-film thickness. If it is not specified, see ISO 12944-5.
NOTE: for verifying dry-film thicknesses as given in ISO 12944-5, acceptance criteria are given therein. The criteria defined above include all measurement uncertainties (for example instrument accuracy, operator skill), provided that the requirements of this International Standard have been met. If the acceptance criteria above are not met, the inspection area shall be rejected (see also ISO 12944 series).
TEST REPORT A
BASIC INFORMATION (test is carried out in accordance with ISO 19840:2012)
A1
Name of project:
A2
Name of owner:
A3
Location of project/structure:
A4
Paint manufacturer(s):
A5
Corrosion protection work carried out by:
A6
Structure:
Area: ....... m
A7
Constituent element:
Area: ....... m
A8
Inspection area (if not A6 or A7):
Area: ....... m
Drawing No.:
Position No(s):
A9 A10
2
2
2
Estimated: Known:
D D
Estimated: Known:
D D
Estimated: Known:
D D
Sketch for identification of inspection area:
B
PROTECTIVE PAINT SYSTEM
B1
Surface preparation, relevant part of ISO 8501:
B2
Surface profile (roughness), ISO 8503-1:
B3
Substrate (e.g. steel, hot-dip-galvanized):
B4
Prefabrication primer:
Nominal (specified) dry-film thickness: .... µm
B5
Priming coat:
Nominal (specified) dry-film thickness: .... µm Nominal (specified) dry-film thickness: .... µm
B6
Intermediate coat:
Nominal (specified) dry-film thickness: .... µm Nominal (specified) dry-film thickness: .... µm
B7
Top coat:
Nominal (specified) dry-film thickness: .... µm Nominal (specified) dry-film thickness: .... µm
C
Measurement/adjustment
C1
Principle of measurement instrument:
C2
Measurement instrument:
Serial No.: Range of probe: Calibration date:
C3
Date of measurement:
C4
Adjustment:
Smooth surface
D
Rough surface
D
This report consists of pages No. .... to .... .
D
Acceptance/rejection criteria: Measurement
1st coat
2nd coat
3rd coat
4th coat
3 Correction value used (see Table 2 of
4 Resulting individual dry-film thickness
5 Individual dry-film thicknesses outside of
ISO 19840:2012)
Column 2 minus column 3 µm
the specification
µm NDFT (individual coat) Cumulative NDFT 80% of the cumulative NDFT Maximum cumulative dry-film thickness E
Results Project: Corresponding drawing No: Number of measurements to be taken in accordance with ISO 19840:2012, Clause 6: 1 Measurement No.
2 Individual reading
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 .. Arithmetic mean Number of measurements: Number of measurements between NDFT and 80 % NDFT: Percentage of those measurements compared with the total number of measurements: Number of measurements less than 80 % NDFT: Number of repeated measurements: Ambient temperature during the measurements (°C): Surface temperature during the measurements (°C): Remarks:
Work conforms to the requirements?
yes/no
Name(s) of the inspector(s): Place and date:
Signature(s):
STATION - 7
HIGH VOLTAGE SPARK TESTING (ASTM D 5162)
ASTM D5162, “Practice for Discontinuity (Holiday) Testing of Nonconductive Protective Coating on Metallic Substrates” PINHOLE & HOLIDAYS Holidays/Discontinuity – skips or misses in the coating/lining system Pinholes – tiny voids in the coating or lining that penetrate to the substrate Caused by: Areas missed by the applicator (holidays) Outgassing of the coating; poor wetting of the coating/lining on the surface during application (pinholes) Typically found on difficult access areas/non-uniform surfaces (behind angles, corners, welds, bolt threads, inside holes, between back-to-back angles, etc.)
When Holiday detection is performed? After final coat has been applied and after fully cured (i.e. 6 to 8 days (refer PDS). Specifications may require holiday testing after the application of each coat Cannot use wetting agent in water for “between coat” pinhole detection Cannot perform pinhole detection on a coating already in service Coating must be nonconductive Substrate must be conductive High voltage (spark) testing requires voltage setting 100 to 125 volts/mil (per 25 µm) Obtain recommended test voltage from coating manufacturer ASTM D5162 provides voltage chart & formula PROCEDURE 1. Attach ground cable to detector unit 2. Attach electrode cable to detector 3. Select test voltage 4. Verify accuracy of test voltage setting using a peak reading voltmeter 5. Attach ground wire to bare substrate 6. Power-up detector 7. Test surfaces (move wand 30 cm [1 foot]/ second) 8. Mark holidays with chalk or other marker that is removable 9. Only re-inspect repaired areas DOCUMENTING HOLIDAY DETECTION Type of inspection (low or high voltage) Manufacturer, model No. and serial No. of detector If high voltage, the test voltage used and the method used to verify test voltage
Area of structure inspected Location of holidays/pinholes Methods used to repair coating/lining Results of retesting (if performed)
STATION - 8
LOW VOLTAGE WET SPONGE HOLIDAY TESTING
PROCEDURE 1. Attach ground wire to detector unit 2. Attach sponge wand wire to detector 3. Attach ground wire to bare substrate 4. Saturate sponge with tap water. May use wetting agent in water if coating thickness is 250-500 µm (10-20 mils) 5. Power-up detector 6. Verify unit is operational (correct sensitivity) 7. Test surfaces (move wand 30 cm [1 foot]/ second) 8. Mark pinholes with chalk or other marker that is removable DOCUMENTING HOLIDAY DETECTION Type of inspection (low or high voltage) Manufacturer, model No. and serial No. of detector If high voltage, the test voltage used and the method used to verify test voltage Area of structure inspected Location of holidays/pinholes Methods used to repair coating/lining Results of retesting (if performed)
STATION - 9
ASSESSMENT OF PULL-OFF TEST
Adhesion Break: A break between coating layers or between the substrate and first coating layer Cohesion Break: A break within a single coating layer Glue Break: Coating adhesion and/or cohesion strength exceeds bonding strength of the adhesive If multiple locations of break occur, estimate the % of each E.g., 75% cohesion within primer; 25% adhesion between primer and intermediate coats
STATION - 10
ADHESION TESTING BY THE CROSS CUT METHOD (ISO 2409)
SELECTING THE CORRECT CUTTER BLADE The cutter blade is selected based on the substrate type, coating thickness and the test method being used, see table below. Coating Thickness Microns 0-60 61-120 121-150
Test Method ISO (Hard Substrates) 6 x 1mm 6 x 2mm 6 x 3mm
ISO (Soft Substrates) 6 x 2mm 6 x 2mm 6 x 3mm
The crosscut test is not suitable for coatings of total thicknesses greater than 250 μm. NOTE: For coatings of total thickness greater than 250 μm, the X-cut method described in ISO 16276-2 can be used.
TEST PROCEDURE: ISO 2409 (Cross Cut)
Place the cutting edge on the sample.
Press down gently and pull the
adhesion tester towards you in one steady movement to make a series of parallel cuts approximately 20mm long. Apply sufficient pressure to ensure you cut right through the
coating to the surface of the substrate. • If the substrate is wood or similar, make cuts at a 45° angle to the direction of the grain.
1 2
3
Place the cutting edge on the sample at a 90° angle to the first cut and repeat Step 2 to create a lattice pattern on the coating.
Brush the sample lightly several times, forward and backwards along the diagonals of the lattice, to remove debris.
Inspect the sample to ensure that the cuts have penetrated all the way through the coating. Remove and discard two complete turns of adhesive tape. Remove an additional length of tape at a steady rate and cut apiece approximately 75mm from this length.
Centre the cut piece of tape over the lattice and smooth into place using a finger. Rub the tape firmly using a finger nails or finger tip to ensure good adhesion between the tape and the coating.
Within 5 minutes of applying the tape, remove the tape by pulling in a single smooth action taking approximately 0.5 to 1 seconds at an angle of 60° to the surface.
To maintain a permanent record of the test, retain the tape by applying it to a transparent film.
Assess the coating adhesion by viewing the lattice of cuts in good light. If agreed, use an eyeglass to aid viewing. Compare the lattice of cuts with the ISO 2409 standards table shown in Section 5 ‘Assessing the results.
Test report The test report shall contain at least the following information: All details necessary to identify the product tested; A reference to this International Standard (ISO 2409:2013); Details of the preparation of the test panels, including: • The material, the thickness and the surface preparation of the substrate
• The method of application of the coating material to the substrate, including the duration and conditions of drying between coats in the case of a multi-coat system
• The duration and conditions of drying (or stoving) and ageing (if applicable) of the coating before testing.
• The thickness, in micrometers, of the dry coating and the method of measurement used in ISO 2808, and whether it is a single coating or a multi-coat system.
The temperature and relative humidity during the test, if different from those specified.
The type of cutting tool used and the method of operation (manual or motor-driven);
Details of the method used to remove loose paint The results of the test
Any deviations from the procedure specified;
Any unusual features (anomalies) observed during the test;
The date of the test.
Table 1 — Classification of test results Appearance of surface of crosscut area from which flaking has Classification
0
1
2
3
4
5
Description
a
occurred (Example for six parallel cuts)
The edges of the cuts are completely smooth; none of the squares of the lattice is detached Detachment of small flakes of the coating at the inter- sections of the cuts. A crosscut area not greater than 5 % is affected. The coating has flaked along the edges and/or at the intersections of the cuts. A crosscut area greater than 5 %, but not greater than 15 %, is affected. The coating has flaked along the edges of the cuts partly or wholly in large ribbons, and/or it has flaked partly or wholly on different parts of the squares. A crosscut area greater than 15 %, but not greater than 35 %, is affected. The coating has flaked along the edges of the cuts in large ribbons and/or some squares have detached partly or wholly. A crosscut area greater than 35 %, but not greater than 65 %, is affected. Any degree of flaking that cannot even be classified by classification 4.
—
The figures are examples for a crosscut within each step of the classification. The percentages stated are based on the visual impression given by the pictures and the same percentages will not necessarily be reproduced with digital imaging. a
STATION - 11
MEASURING MEK RESISTANCE OF ETHYLE SILICATE (INORGANIC) Reagents and Materials • Methyl Ethyl Ketone (MEK), in accordance with Specification D 740. • Cheesecloth, 100 % cotton mesh size grade 28 by 24 approximately 300- by 300-mm (12- by 12-in.) and contrasting in color to the coating being evaluated, or other mutually agreed upon cloth. • Squeeze Bottle. • Proper Safety Equipment, as determined from the solvent MSDS, for example, solvent resistant gloves, respirator. Procedure Select areas on the primer surface at least 150mm (6in.) long on which to run the tests. Clean the surface with tap water or dry cloth to remove loose material. NOTE 1—Tap water may influence the cure of the zincrich primer. Measure the dry film thickness of the primer in the selected areas in accordance with Test Methods D1186, D 1400 or D 4138. Mark a 150- by 25-mm (6- by 1-in.) rectangular test area on the undamaged cleaned surface using a pencil or other suitable solvent resistant marker. Fold the cheesecloth into a pad of double thickness and saturate it to a dipping wet condition with the methyl ethyl ketone. Do not allow more than 10 s to elapse before proceeding to the next steps.
Place the properly protected index finger into the center of the pad while holding excess cloth with the thumb and remaining fingers of the same hand. With the index finger at a 45° angle to the test surface, rub the rectangular test area with moderate pressure first away from the operator and then back towards the operator. Complete each double rub (one forward and back motion) in about 1 s. Continue rubbing the surface with the MEK saturated pad, wetting the pad as necessary without lifting it from the surface, until either the metal substrate is exposed or 50 double rubs have been completed. If the former, record the number of rubs when the substrate is exposed. Select an adjacent area to be used as a control. Repeat, except use dry cheesecloth to establish the effect of burnishing without the influence of MEK. Use this area as the control to visually show the appearance of No Effect. Inspect the test areas and the cheesecloths. Rate the results in accordance with below Table 1. TABLE -1 Scale for Resistance Rating Resistance rating
Description
5
No effect on surface; no zinc on cloth after 50 double rubs
4
Burnished appearance in rubbed areas; slight amount on zinc on cloth after 50 double rubs
3
Some marring and apparent depression of the film after 50 double rubs
2
Heavy marring; obvious depression in the film after 50 double rubs
1
Heavy depression in the film but no actual penetration to the substrate after 50 double rubs
0
Penetration to the substrate in 50 double rubs or less
STATION - 12
DETERMINATION OF MAIN GROUPS OF PAINT Groups of Paint Acrylic Epoxy Polyurethane Silicate Silicone Chlorinated rubber Solvent Test • Can be used to identify drying mechanism of unknown old coating • Expose the old coating to MEK solvent • Place paper towel / cloth / rags soaked in the thinner on the coating to be tested • Observe how the coating react Solvent test: Three samples
Solvent test: Three samples Use paper towel to keep the solvent in contact with the sample
Solvent test: Three samples Paper-towels wetted by MEK
Solvent Test: Acrylic (physically drying) Paint sample is dissolved
Solvent Test: Alkyd (oxydatively curing) Alkyd film “lifting”
Lifting and loss of adhesion, solvent act as paint remover. Disregard blue smear from paper towel
Solvent Test: Epoxy (chemically curing)
No change in paint sample
Paint / Coating Failures Paint Flakes
Description: Paint flaking is a form of adhesion failure where paint literally flakes from the substrate. A familiar sight on wood substrates and on galvanizing. Probable Causes: Incorrect paint system used. Either none or incorrect pretreatment used for certain substrate. i.e. non-ferrous or galvanized. Also poor application techniques. May also be attributed to differential expansion and contraction of paint and substrate e.g. wood. Can be the result of ageing of the paint system. Prevention & repair: Always use correct coating system and pre-treatment. Remove all flaking coating until a firm edge can be achieved. Abrade, sweep blast and clean overall and apply suitable coating system to coating manufacturer’s recommendations.
Delamination (also called adhesion failure and Flaking)
Description: Loss of adhesion between coats of paint. Probable causes: Provided compatible paint materials have been used, delamination defects are generally related to poor surface preparation and application defects/such as contamination between coats; exceeding overcoat times; application to a glossy surface. Prevention & repair Ensure no contamination between paint coats, closely follow intercoat times, light abrade and clean glossy surfaces between coats. Depending on extent, abrade and recoat or completely remove the delaminated coating and reapply. ADHESION FAILURE (also called delamination and flaking)
Description: Paint fails to adhere to substrate or underlying coats of paint Probable causes: Surface contamination or condensation Prevention & Repair: Ensure that the surface is clean, dry and free from any contamination and that the surface has been suitably prepared. Use the correct coating specification. Depends upon the extent of adhesion failure. Removal of defective areas will be necessary prior to adequate preparation and application of correct coating system to manufacturer’s recommendations.
STATION - 13
INSPECTION OF PAINTED SURFACES
“COATING DEFECTS” PHOTOGRAPHS Sagging
Sags are the downward movement of a coat of paint which appear soon after application and before setting, which results in an uneven area with a thick lower edge. They are usually apparent on local areas of a vertical surface and in severe situations may be described as curtains.
Sags/ Curtains/runs
DRY SPRAY
FISH EYES
HOLIDAYS
ORANGE PEEL
PINHOLES
POPPING
WRINKLE / LIFTING
SOLVENT ATTACK/LIFTING (ALSO CALLED WRINKLING)
AMINE SWEATING / BLUSHING / CARBONATION
Blooming & Blushing
OSMOTIC BLISTERING
BLISTERING
PIN POINT RUSTING
CRACKING
DELAMINATION
CHALKING
BLEEDING
VACUOLES
RUST SPOTTING
MUD CRACKING
CRATERING
ADHESION FAILURE (FLAKING, DELAMINATIO
SAPONIFICATION
CHECKING
POOR SPRAY APPLICATION
INCOMPATIBLE COATING SYSTEMS OR INCORRECT COATING SYSTEM
STATION - 14
“CORROSION” PHOTOGRAPHS
GENERAL CORROSION
GALVANIC CORROSION
CREVICE CORROISON ON FLANGE
Cavitation
EROSION CORROSION
Stress corroison
MICROBIOLOGICAL CORROSION
STATION - 15
Painting Project Daily Data Log Book Coatings: Inspection Coating Inspector and Applicator - Verify Ambient Conditions: • Measure & record the Surface Temperature of the substrate (object • painted) • Measure and record the Air Temperature within 2 ft of the part • Measure and record the Relative Humidity within 2 ft of the part • Measure and record the Dew Point Temperature within 2 ft of the part • The Surface Temperature of the part must be 5º F ≥ greater than the Dew • point Temperature or no painting can be performed. • Shelf life Expiration Date: One year for most Epoxies (Check with Mfg.) • Record the date, time, joint number, location, Etc. for the data book to • protect all parties, Coatings: Mixing, Thinning, Application Coating Inspector and Applicator - Verify Coating Material Inventory: • Condition of containers/storage: Damage? • Storage: Are the coatings materials protected from the environment, are • temps within Mfg. guidelines • Number of components: 2 Part / 2 to 1 Ratio • *Record Manufacturer, product no., color • *Record Batch/Lot No. • Shelf life Expiration Date: One year for most Epoxies • Record this information for the data book to protect all parties Coatings: Inspection: Final Visual Inspection Critical last steps • • • • • • • •
Perform visual and holiday inspection simultaneously if possible with applicator. Make all repairs in accordance with Specification No paint stick repairs. Two part epoxies or inner tape wrap followed by a water activated fiberglass wrap or two part epoxy followed by an H2O activated outer wrap are acceptable alternatives. Re-Inspected the all repaired areas.
Paint Inspection:
Date: / Project #:
Daily Coating Inspection Report
Inspector:
Project/Client: Location: Description: Requirements: Contractor: Description of Areas & Work Performed
/
M T W Th F S Su
Pg.
Of COPY To:
QC Mgr
Owner
Contr
Attachments: DFT Sheet
Revision # Hold Point Inspections Performed 1 Pre Surface Pep/Condition & Cleanliness 2 Surface Preparation Monitoring 3 Post Surface Preparation/Cleanliness & Profile 4 Pre Application Prep/Surface Cleanliness 5 Application Monitoring/Wet Film Thickness (WFT) 6 Post Application/Application Defects 7 Post Cure/Dry Film Thickness (DFT) 8 Nonconformance/Corrective Actions Follow-up 9 Final Inspection Approved By: Surface Conditions Ambient Conditions Time (Indicate AM or PM) : : : : New Maint Primer/Paint Age/Dry/Cure 0 o o o o Dry Bulb Temp (C/F) Steel Galvanize Concrete Other 0 o o o o Wet Bulb Temp (C/F) Hazard Sample Report # Degree of contamination: % Relative Humidity % % % % o o o Fe ppm pH µg/cm2 / ppm Surface Temp0 (C/F) Min/Max Test: Cl / / o / / 0 o o o o Dew Point Temp (C/F) Degree of Corrosion: Scale Pitting/Holes Crevices Sharp Edges Wind Direction/Speed Weld Moisture Oils Other Weather Conditions: Application Painted Surface Condition: Start Time : Finish Time : Est. Sq/ft. Dry to: Recoat Touch Handle Primer Intermediate Topcoat Touch-up Runs/Sags Pinholes Holidays Dry/Over Spray Abrasion Fall Out Other Generic Type: Qty Mixed: Surface Preparation Manuf.: Mix Ratio: Prod Name: Mix Method: Start Time: Finish Time: Est Sq/ft: Solvent Clean Hand Tool Power Tool Prod #: Strain/Screen: oF HP Wash PSI Other Color: Material Temp: Sample Kit Sz/Cond.: Abrasive Blast Abrasive Type Sweat-in Time: Min/Hrs Blast Hose Size Nozzle Size / PSI Shelf Life: Pot Life: Min/Hrs Batch #'s Air Supply CFM Air Supply Cleanliness Reducer #: Water/Oil Trap Check Equipment Condition Check (A) Qty Added: Pt/Qt/Gal (B) % by Vol: % Specified WFT Avg: Surface Cleanliness & Profile Measurement (C) Mils Achieved WFT Avg: Job Specification SSPC/NACE - SPReducer: Mils SSPC/NACE Spec / Visual Stds Airless/Conv. Spray Brush Roller Other Profile Check: Disc Tape Gauge Pump Pot Hose Dia. Air Check Specified mils avg. / Achieved mils Ratio/Size Hose Lng. SEP/Trap GPM/CFM Spray Gun Filter Surface effect on DFT Gauge/BMR mils Dry Film Thickness PSI Tip Sz. Agitator Gage Type / Model
Gage Serial #
Gage Calib. Spec Avg. Verified DFT
Total Avg DFT
DFT Last Coat
Spec #
NCR/CAR
DFT This Coat Inspector's Signature
Date .