Chapter Q's Flashcards
What is the inspector’s responsibility when it comes to safety on a project?
The inspector is not responsible for safety enforcement but should report on any issues that may effect the project.
How does NACE define the inspector’s role?
The book: quality control technician responsible for observing and reporting conformance or deviation for the projects specifications
Name some tests that may need to be conducted during surface preparation and coating operations.
Temperature, relative humidity, due point, surface cleanliness, Anchor profile
Name some of the documentation/reports that may be required to be maintained on a coatings project.
Daily reports, weekly reports, material usage reports, manpower and equipment, non conformance and conformance
What are the most important characteristics of a good report?
Accuracy, detailed, objective
What is the inspector’s primary responsibility and what should the inspector not do as it pertains to the specification
Enforce the specifications, but can never change the specification for any reason
What type of information could you expect to find on a product data sheet?
Surface preparation and application information such as…
Recommended level of surface cleanliness
Recommended application methods
Recommended equipment (such as tip size)
Environmental parameters for application
Max and min temps
Curing times
Recoat windows
What type of information could you expect to find on a material safety data sheet?
Health, safety and environmental, PPE required - physical characteristics - emergency responder information.
Explain the difference between quality assurance (QA) and quality control (QC).
QA: Any systematic process of checking to see weather a product or service being developed is meeting specified requirements.
QC: a procedure or set of procedures intended to ensure that a manufactured procurement or preformed service adheres to the defined set of quality criteria or meets the requirements of the client or customer.
Define corrosion:
The deterioration of a substance, usually a metal from a reaction with its environment.
What is passivation?
A layer or oxides formed on the surface of a metal that provides corrosion protection, stainless steal for example
What are the elements of a corrosion cell?
Anode, cathode, metallic pathway, electrolyte
Describe what happens at the anode.
The metal dissolves into the electrolyte
The anode is the part that dissolves
What is the function of the electrolyte?
Allows that passage of ions to connect the corrosion cell.
What is the function of the metallic pathway?
Transfer electrons. Allows the flow of electron to connect the corrosion cell.
The general rules of galvanic corrosion are:
The less noble (more reactive) metal when connected to a more noble (less reactive metal) will corrode preferentially
Name at least five factors that affect the rate of corrosion.
Humidity - (wetness) the wetter the more corrosion
Oxygen - more oxygen - faster corrosion
Chemical salts - increases corrosion due to increasing the efficiency of the electrolyte
Pollutants - (acid gases)
Temperature - higher temp- faster corrosion
General corrosion is:
Results in a Relatively uniform loss of material over the entire surface.
Results in a general thinning of the affected surface
Relatively easy to inspect
Does not cause catastrophic failures
Localized corrosion is:
Typically pitting and crevice corrosion
It is typically the most concerning as damage is concentrated and loss of integrity or structural failure can result
List some of the common tools/methods used for corrosion control
- design - build to avoid corrosion
- inhibitors - additives that slow corrosion
- metal selection - choose better material
- cathodic protection - using another metal attached with a pathway that will corrode instead (becomes the anode)
- protective coatings
- splash zone systems
- alteration of the environment
What is the galvanic series?
A list of metals in order or reactivity (more or less noble) in seawater at 25° C
Identify some of the defects that can be caused by incorrect application temperatures.
Failure to cure
To rapid solvent evaporation
Poor film formation
Describe relative humidity.
• Measure of the amount of moisture in the air compared to
saturation level.
- May affect the coating if too high or too low.
- Too high may cause solvent entrapment.
What is the dew point temperature?
Me: The temperature in which moisture will begins to form the the surface of steel
Wit rate should be 5° above. The due point for applications
Name some of the effects wind may have on a coating project.
- Blowing abrasives
- Causing excessive overspray
- Accelerating solvent evaporation
- Contributing to the formation of dry spr
What are some of the common errors when using an electronic hygrometer?
Failure to acclimate instrument to the environment with accurate time
Explain the process for use of the sling psychrometer.
• Make sure the wick is wet and clean.
• Continue to “sling” until consecutive readings are
achieved
(3 consecutive readings is a good practice).
List three (3) desirable properties of a coating.
Chemical resistant water resistant Ease of application Adhesion to substrate Cohesive strength Flexibility and elongation Impact Resistance abrasive resistance Temperature resistance Dielectric strength
Two (2) broad classifications of a coating are:
Organic - convertible - thermosetting
inorganic – non-convertible - thermoplastic
What are two (2) primary components of a liquid applied coating?
Pigment
Vehicle – (resin, binder and solvent)
Describe the three (3) methods by which a coating provides corrosion control
inhibited, sacrificial, barrier
What are the three (3) different ways a coating can adhere to the surface?
Chemical, mechanical, polar or a combination of all three
Effects of Corrosion (why act against corrosion)
Safety
Cost
Appearance
The two broad classification for curing mechanisms are:
Convertible
Non-Convertible
List two (2) Non-convertible coating types.
Chlorinated Rubber
Vinyl
List three (3) convertible coating curing mechanisms.
Oxidation
Co-reaction (polymerization)
Hydration
Fusion
List two (2) characteristics of oxidation cure coatings.
Not suitable for immersion service
Not suitable for use over alkaline substrates
Limited dry film thickness per coat
List three (3) coating types that cure by polymerization.
Epoxies Polyurethanes Polyureas Polyaspartics Polysiloxanies
Induction time is
the time required by the product data sheet (coatings manufacturer) between mixing the coating and the start of application.
What is a main requirement for a hydration coating to cure?
Moisture
Industrial and marine coatings are commonly referred to by
generic resin type.
Oil based coatings applied over alkaline surfaces may result in
Saponification
List five (5) of the formal sections usually contained in a good specification.
Scope of work Terms and definitions Reference standards and codes Safety Pre-job conference Surface preparation Coating materials (includes the coating schedule) Sampling coatings Workmanship Application Work schedule (sequence of work to be done) Repairs and remedial coating work Inspection Documentation
What are two of the inspector’s responsibilities as it relates to the
specification?
Enforce the specification.
NOT to make changes to the specification.
During surface preparation, surface cleanliness should be inspected (as a minimum) the following three (3) times:
Before any surface preparation activities
After surface preparation, before coating begins
Between each application of coating in a multi-coat system
Factors during surface preparation that may effect service life include:
Residues of oil, grease, and soil
Residues of (non-visible) chemical salts
Rust on the surface
Loose or broken mill scale
Rust scale
Anchor pattern
Defects mechanical cleaning equipment
Surface condensation
Old coatings that may have poor adhesion or may be too deteriorated for recoating
Existing coatings that may be incompatible
Common design defects include:
Hard-to-reach or inaccessible areas
Rivets, bolts, or other connectors
Welds
Gaps (particularly skip welds or surfaces close together)
Overlapping surfaces (e.g., roof plates in water tanks)
Angle iron badly oriented or in complex arrangements
Threaded areas
Dissimilar metals
Sharp edges, particularly on corners or rough cut plate
Construction aids
Common fabrication defects include:
Weld Spatter
Skip Welds
Rough Welds
Sharp Corners & Edges
Four (4) Typical SSPC SP1 pre-cleaning methods include:
Solvent wipe with cloth or rag Immersion of the substrate in solvent Solvent spray Vapor degreasing Steam cleaning Emulsion cleaning Chemical paint stripping Use of alkaline cleaners
One Standard for use with Power Tool Cleaning is:
ISO St2
ISO St3
SSPC SP-3
SSPC SP-11
Four (4) Examples of tools used for Power Tool Cleaning are:
Rotary Wire Brushes Impact tools Needle Scaler Rotary Scalers Piston Scalers Grinders and sanders Disc Sanders
Two (2) Abrasive Blasting methods include:
Centrifugal blasting Sand-injected water blast Slurry blast Wet abrasive blast Dry Grit Blast Cleaning (Air Blasting)
Visual Standards for abrasive blasting include:
SSPC-Vis 1
ISO 8501-1
SSPC SP 5/NACE 1 limits staining to
SSPC SP 10/NACE 2 limits staining to
SSPC SP 6/NACE 3 limits staining to
0% per each unit area
5% per each unit area
33% per each unit area
The two (2) types of abrasive blasting nozzles include:
Straight
Venturi
The specified level of surface cleanliness must be achieved and maintained
immediately prior to coatings application.
Advantages of centrifugal blast equipment include:
Dust and fines are contained
Abrasives are easily recycled
Blasting and priming can be an inline operation
General overall economy compared to air blasting
No compressors, piping, or air handling equipment needed for wheel blasting
The Inspector’s checklist for surface preparation should include:
Ambient Conditions Conditions of substrate Pre-Blast surface cleanliness Shot/Grit size selection Shot/Grit Cleanliness Abrasive Blasting Equipment Surface Profile Surface cleanliness after abrasive blasting Operator qualifications Safety
Abrasive media types include:
Shot & Grit (metallic) Crushed Slag Ceramic Grit Silica Sand Garnet Agricultural Abrasives Specialty Abrasives
List the pressure ranges that categorize:
Low Pressure Water Cleaning: 210 MPa (30,000 psi)
Three (3) types of Water-Blasting include:
Grit Blasting with a Shroud
Sand Injected Water Blast
Slurry Blast with Grit/Water Mix
The NACE/SSPC Waterjetting Standard is:
NACE 5/SSPC-SP12. SSPC/VIS 4 and VIS 7 are visual comparators to be used with the standard.
Three (3) Test Methods for surface profile include:
Comparator and coupons
Replica tape
Digital Surface Profile Gauge
