What is the cause of chalking in epoxy coating
UV or radiation exposure
What is polymerization cured coating?
Two parts mixed together just prior
... [Show More] to use
Examples of non-convertible coatings
1. Chlorinated rubber 2. Vinyl 3. Acrylic 4. Bituminous
Non-convertible curing def.
No chemical change during cure cycle
Convertible curing def.
Some chemical change during cure cycle
What info should be included when sending samples to a lab?
1. Identity of materials 2. Properly packed/labeled samples 3. Chain of custody form 4. Type of analysis that is expected and the concentrations of interest
Specialized tests or equipment coating inspectors may encounter
1. AA/AE Atomic Absorption/Emission 2. ISP Induction coupled plasma Spectrometer 3. GLC Gas liquid chromatographs 4. IR, FTIR, FTIR-ATR INfrared spectrophotometers 5. DSC Differential scanning calorimeters
What is a cathodic dis-bondment test?
Procedure to determine how easily a coating loosens from a substrate or develops holidays as a result of normal soil potentials
Individuals who perform surveys
1. O-Cat or S-cat tech 2. NACE coating specialist 3. NACE Level III 4. Coating Inspector w/field experience 5. Coating manufacturer representative 6. Maintenence engineer with specific plant knowledge.
Coating survey steps
1. Understand scope 2. Gather team 3. Develop survey plan 4. Review standards 5. Agree on format 6. Delegate various tasks 7. Eveluate existing coating 8. Delegate various tasks 9. Evaluate existing coating 10. Gather additional info 11. Summarize data 12. Prepare maintenance plans 13. Prepare reports/input data 14. Submit final survey reports.
List some of the primary reasons surveys are performed
1. Plan maintenance. 2. Prioritize work 3. Budgetary concerns 4. Determine value of assets 5. Legal compliance
Definition of a coating survey
Gather baseline info needed to plan maintenance coating procedures
What are faying surfaces and why not galvanize them?
Surfaces that depend on friction to hold galvanizing it may/will reduce friction if they are galvanized
Common problems seen during the usual inspections of HD galvanized items
1. Cracking 2. Peeling 3. Bare spots 4. Lumps 5. Blisters 6. Flux inclusions 7. Ash inclusions 8. Dross inclusions
Post galvanizing treatments and why
To Remove Thickness: Roll, Wipe, Centrifuge/Air Blast
To change properties/To alloy: Annealing
Temperature range for galvanizing kettle
820-850 F
Purpose of pickling
Hydrochloric or sulfuric acid bath to remove oxides and mill scale
Purpose of caustic cleaning
Acid bath or caustic to remove dirt, oil and grease
Stages of hot dip process
1. Surface prep. 2. Galvanizing 3. Post treatment 4. Inspection
Hot dip galvanizing safety
1. Can stay for some time 2. Molten metal splash 3. Nascent hydrogen above kettle
Usual layers of galvanized coating consists of:
1. ETA=100% Zn 2. ZETA= 94% Zn 6%Fe 3. DELTA= 90% Zn 10 Fe 4. GAMMA= 75% Zn 25% Fe
What is hot dip galvanizing?
Coating iron or steel with zinc at temperatures of 820-860 F
If a maintenance coating to be applied is incompatible with the existing coating system__________may occur
Curling
______________ is performed at the work area by working the edges of the repaired area back to achieve a fairly smooth transition from the repair area to sound coating.
Feathering
With regards to maint. coating all parties should agree on___________?
1. Spot repair requirements 2. Feathering 3. Appearance of repaired areas
Maint. coating selection process should take the following into consideration:
1. Compatability with existing system 2. Surface prep. 3. If abrasi ve blast is permitted and feasible
When determining coating system life cycle the following should be considered:
1. Maint. costs 2. Length of coating life 3. Initial and maint. material costs 4. Intial and maint. labor costs
Life cycle of a coating system can be affected by:
1. Service environment 2. Maint. intervals 3. Coating system chosen 4. Surface condition
Maint. coating operations are defined as:
Applying coating over a substrate that has been installed in its final environment and placed in service
Some service situations where permeation may occur include:
1. Sour crude storage tanks 2. Cooling towers 3. Fertilizer plants
Special substrated that have tightly adherent oxide films include:
1. Stainless steel 2. Tin 3. Nickel 4. Cadmium
Non-Ferrous substrates include:
1. Stainless steel 2. Nickel 3. Copper/Nickel alloys 4. Aluminum 5. Aluminum bronzes 6. Copper 7. Bronzes 8. Brass 9. Tin 10. Cadmium 11. Lead 12. Magnesium
Common reasons wood is coated
1. Decoration 2. Protection 3. Sealing 4. Stabilization 5. Preservation 6. Flame retardence
The following materials can be used to repair fusion bonded epoxy:
1. Epoxy FBE melt sticks 2. LIquid epoxy 3. Repair patches
Destructive tests for heat shrink sleeves include_____________
Peel test
Non destructive tests for heat shrink sleeves include
1. UT 2. Physical inspection 3. Holiday inspection
Pipeline coating field joints include
1. Heat shrink sleeves 2. Insulation 1/2 shells 3. Liquid epoxies 4. Cold applied tape 5. Hot applied tape 6. Fusion bonded epoxy 7. Wax tape
Concrete coating characteristics include:
1. Good for wetlands 2. Can be applied in may thicknesses
General application for CTE includes
1. Prime pipe 2. Apply CTE dope 3. Wrap w/glass fiber mat 4. Apply 2nd coat of CTE dope 5. Apply 2nd layer of glass met 6. Apply outer wrap of CTE impregnated glass fiber felt. 7. Cool
Disadvantages of CTE coatings include:
1. Environmental concerns 2. Subject to corrosion and damage from soil stress
Advantages of CTE pipeline coatings
1. Ease of application 2. Long life
FBE process includes:
1. Preheat 2. Grit/shot blast to NACE #2 SSPC-SP10 3. Heat pipe 4. Apply coating 5. Cure coating 6. Quench 7. Stencil
Common characteristics of FBE include:
1. Typically green or red 2. Single or two layer 3. DFT from 10-20 mils
Typical plant applied coatings include
1. Two layer poly 2. 3 layer poly 3. FBE 4. Coal tar enamel 4. Asphalt 5. Concrete 6. Asphalt
The majority of the pipes coated at a facilty or plant and shipped to site are called:
Plant applied
Construction materials may include:
1. Steel 2. Aluminum 3. Stainless steel 4. Plastic
Proper safe accurate operating procedure for low voltage holiday detector
Ground equipment and set for coating thickness VS voltage. Keep probe in contact with work, move slowly across surface. Don't oversaturate sponge
Standards used for dry film measurement of coatings over concrete
ASTM-D6132-97 and SSPC-PA9
DFT of coating on concrete can be measured by:
UT thickness guage
Which organization produces comparator plates for various prepared concrete surfaces?
International concrete repair institute
Disadvantages of plural component airless spray over single piston:
1. Higher costs 2. Education for mechanic is higher 3. Heaters require HV electric 4. Applicators job is more difficult
Advantages of plural component airless over single piston:
1. Automatic, accurate material mixing 2. Ability to spray thick materials w/o thinning 3. Ability to spray materials 2/short pot lives.
4 stages powder goes thru when heat is applied?
1. Flow 2. Wetting 3. Gel 4. Curing
Two curing categories of powder coating
1. Thermoplastic: Softens when heated 2. Thermo-setting: Hardens when heated
Characteristics of flouropolymer coatings?
1. Non-stick 2. High temperature resistance
Two main types of fireproofing coatings
1. Passive 2. Intumescent
Three main types of anti-fouling coatings
1. Ablative 2. Self smoothing 3. Foul release
What are anti fouling materials and how do they work?
They are materials that make ships hulls distasteful, or too slick for bio-fouling material to attach
Surface prep for lining installation
White metal blast SA3/NACE1/SSPC 5
Describe wicking
1. Liquid travels along fibers path and can cause substrate to corrode, blister or delaminate
What does re-enforcing add to a resin?
Strength
Some resins used in re-enforced linings:
1. Polyester 2. Epoxy 3. Vinyl ester
Lining Definition
A coating normally in immersion service
Thermal spray safety practices
1. HP rated hoses 2. Never use compressed air to clean work area or clothing 3. Don't use plant air for breathing air
Common hazards associated with specialized applications
1. Fume/dust inhalation 2. Electrical shock 3. Burns 4. Falling objects
Disadvantages of water jetting
1. Expensive equipment 2. Water injection danger 3. Surface needs anchor profile 4. Collection/Disposal of water
Water jet advantages:
1. Less dangerous 2. Better air quality 3. Less stringent respiratory requirements 4. Less environmental damage 5. Less clean up
Water jetting safety items include:
1. Barricade work area 2. Protect electrical equipment 3. Electrical connections dry 4. Make sure hoses and fittings are not worn excessively and are rated for use
Two condsiderations w/regards to back thrust
1. Operator body weight 2. Alternating operators (fatigue etc.)
Water jetting is effective for removing:
1. Surface oil or grease 2. Rust 3. Concrete spatter 4. Existing coatings
Typical water jetting team
1. Nozzle operator 2. Pump operator 3. Additional operators or workers
Requirements for NACE 5/SSPC-SP12
1. Visual contaminants 2. Non-visual contaminants
Robotic water jetting
1. A cleaning vehicle that attachs itself by vacuum, cables or magnets and is controlled by a single operator
Inspection concerns during centrifugal blasting
1. monitor dust collector 2. monitor amperage of motors 3. monitor conveyor line 4. monitor line speed 5. inspect surfaces leaving line for spec. conformance
Well balanced operating mix of abrasives will:
1. provide consistency of finish 2. Ensure uniform abrasive coverage
Functions of a centrifugal blast machine separator include:
1. Control size of abrasive mix 2. Remove contaminants 3. Control abrasive consumption
Low amperage reading on centrifugal blast machine could signify:
1. Abrasive starved wheel 2. Flooded or choked wheel
Efficiency of a centrifugal blast wheels depends on:
1. abrasive operating mix 2. abriasive size 3. quantity and direction of thrown abrasive 4. condition of feed parts
Centrifugal blast systems have these elements
1. Centrifugal abrasive blast wheel 2. Blast cabinet 3. Material handling system 4. Abrasive recycling system 5. Dust collector 6. Abrasives
Portable centrifugal blast systems can be used on:
1. Ship decks, hull sides and bottoms 2. Storage tanks 3. Concrete floors 4. Highways and bridge decks
Centrifugal blast conveyor systems are commonly used for cleaning:
Plate and rolled structural shapes
Basic centrifugal blast set ups include:
1. Tumbling mills 2. Multi table machines 3. Plain table machines 4. Swing tables 5. Custom designed systems [Show Less]