coatings forensics for roofing · dft (astm d4138) micrometers tend to give ... coatings forensics...

International Roof Coatings Conference

Coatings Forensics

For

Roofing

Steven Heinje

Technical Service Manager

Quest Construction Products

July 17, 2012

International Roof Coatings Conference Coatings Forensics for Roofing

The Author: Micro-Bio

Scope & Goals

The Forensic Investigation Nature and Dynamics

Science & Presentation

Failure Risk Model

Defect Occurrence Model

Pattern Recognition

Field Tests Moisture Survey

Sampling

Methods Performance

Descriptive

Case Study

Field Flow Chart

Analytical Methods

“Finger Print” methods

Photomicroscopy Digital Image Processing

Laboratory Flow Chart

Resources

Questions

Outline

Micro-Bio


Education: Bachelorette in Biology/Chemistry („83)

MBA (‟11)

Work: United Coatings/QCP Mfg. for >28 years Primary Roles:

Product Development (esp. Formulation)

Management & Environmental

Codes, Regulation, Standards

Industry and Advocacy ASTM, RCMA, RRCI, RCI, ACS, NPCA, ASQ

V.P. of RCMA

Treasurer of Inland Northwest ACS

Scope of Forensics


Service Life Prediction

& Material Science

Early Failures

Reverse Engineering

Building Science

Early Failures


Jonathon W. Martin, A Systems Approach to Service Life Prediction Problems for Coatings Systems,

ACS Series 722, NIST, 1999

A C

B

Region A: Early Failures

Mostly installation, less often Material Defects,

sometimes “Lack of Robustness”.

Region B: Random Failures

Region C:

Wearing Out, Capability

The Forensic Investigation


Nature and Dynamics

Similar to Litigation:

a solution/settlement is the goal, not blame/science

Root cause is often known by one stakeholder

Appearing to have a vigorous defense is key


Be professional, but not erudite

Burn no bridges, and avoid prognostications on job site

The Forensic Investigation


The stakeholders have biases that

are not data-based

Our products are sight manufactured

- We have a built-in credibility

problem

There are far more variables with

coatings than with prepared roofing

- We carry a high burden of proof

Failure Risk Model


J.M. Juran, Quality Control Handbook, 3rd edition; 1979

Failure Risk Model


Failure

Risk

Model


Category Factor Varia t ion (2d)

Solids (SBV) +/- 2%

Resin (PVC) +/- 2/3% (depends on metering)

Color +/- 1%

Air Entrainment +/- 3% (in >120KU “latex” mastics)

Overa ll +/- 5%

Adhesion Overa ll +/- 20% min

1 coat +/- 10% / coat

Overa ll: 3

coa t s

+/- 17% or less (cross ha t ch ing

mit iga t es)

Solar/HeatUp to 100% as temperature, but possibly

3200% from a kinetics perspective

Solar/UV Up to 100%, typically less

Moisture

Often low, <10% in open areas/low slope;

but in steep slope/prevailing wind over

100%

AbrasionFollows wind turbulence dynamics, over

100%.

Overa ll 173%

Substrate

surface cohesive

strength

>200% on wood; >100% on concrete;

<50% on polymeric's

Trapped water 10X [1000%] or much higher

Overa ll ~10X [1000%]

Coat ing

Materia l

Physica l and

Flu id

Propert ies

DFT

Weather

Prepara t ion



Under cured sealant over leak

Leading to blisters

Poor Workmanship

Blisters

Photos courtesy of CFS

Pattern Recognition


Chalk: North/South Light Corrosion: Random Crack: DFT

Crack: Right vs. Left…

Preparation: Contaminants

on substrate

What was root cause?

Pattern Recognition


1. Job was done in marginal/cold weather

2. Tint was done by “new guy”

3. Wrong colorant slowed cure and hurt adhesion

4. Potentially exposed to freezing due to long cure cycle


The Author: Micro-Bio

Scope & Goals

The Forensic Investigation Nature and Dynamics


Failure Risk Model


Pattern Recognition

Field Tests Moisture Survey

Sampling

Methods Performance

Descriptive

Case Study

Field Flow Chart

Analytical Methods

“Finger Print” methods


Laboratory Flow Chart

Resources

Questions

Outline: Field Tests

Moisture Survey


Scan with NDT methods: Direction/Wind/Shade

Biological growth

Plaster/Wood moisture meter

Tramex (Impedance)

NIR

Probe wet areas to substrate Delmhorst (Conductivity)

Probe various depths

Cores Bag cores quickly

Attics/ceilings (vapor drive)

Interior Moisture (bath/shower)

Recently insulated roof

prior to 4th coat of paint blistering

Pattern Recognition


Chalk Light Corrosion DFT

Right vs. Left…

Contaminants

on substrate

Other Observations:

•100% No peeling on verticals

•~80% on South

•Really wet and cold!

Pattern Recognition


Other Observations:

100%: No peeling on verticals

~70%: on South only

Its really green here!

Fairly uniform

Find a new metal area on north that peels/cracks too

0.21 correlation follows spray practice (edge)

High DFT is bad?

Chalks on wet/cold [south/lake] side?

Moisture Survey


N

Wind

1

2

3 4

5 6

7

8

9

10

Moisture Survey


1

2 3

11

12

14

SPF

11A

11B

11C

Moisture Survey


0%

5% 4%

10%

2%

4%

SPF

12%

7%

3%

Conclusion:

Leak around protrusion- failed

flashing?

Only 6 small holes in roof

Sampling


1

2

3 4

5

1

2

9

6

8

7

10

11

12

13

Determine

failed flashing

is not cause.

Explore DFT

and find a

problem!

Take enough

samples to

build a

correlation for

DFT to

moisture:

13 holes

Sales Rep’ Sampling

Methodology


Performance Field Test Methods


Tape Adhesion

Peel Adhesion

Reverse D471 “swell” D-903 Peel Adhesion

Bagged Wet sample

Loss-on-Dry Analyzer

Descriptive Field Tests


DFT (ASTM D4138) Micrometers tend to give

higher results than actual

Macro Photography

Camera: Nikon D-90;

Lens: Micro Nikkor85mm

1:2.5G ED

Illumination: Natural Daylight

Descriptive Field Tests


Microscopy (Finescale/Field Microscope)

Sampling Exudate Swabs

Syringe

Watch Glass

Stereo microscope:

A “sun-boiled” coating

(40X)

Micrometers

over state

DFT

Field Tests: Case Study


Gardco Tape Adhesion Kit

Pfund WFT Gauge

Finescale Comparator

Coring Tool

Photo Backpack

Gardco Tape Adhesion Kit

Cutting Tools

Hotcake WFT Gauge

Replacement Insulation Cores

Field Tests: Case Study


Droppers

DFT (magnetic)

Sharpies

Moisture Meter

Loupe

Tripod

Sampling supplies

Thermo/Hygro

85mm Micro lens

IR Thermo

Delmhorst

Micrometer

DSLR

Field Microscope

Numbers

Photocard & scale

Swabs, Syringes…

Field Tests

Flow Chart


Analytical Tests


“Finger Print” methods Low Temperature Ashing (ASTM D3723)

Water Absorption (ASTM D471/D570)

XRF (X-Ray Fluorescence Spectroscopy

FT-IR (Infrared Spectroscopy)


Finger Prints


Low Temperature Ashing (ASTM D3723) Ash is a simple method, but has very high precision

Requires a kiln, a desiccator and an analytical balance or

Automated Ash test (AZI Computrac Max 5000)

It is useful not only in forensics but also production/QC

Provides some qualitative information…

65.8% Pigment

- organic pigments

- waters of hydration

Finger Prints


Water Absorption (ASTM D471/D570) Provides important qualitative information

Detects Production Defects

Can be used for chemical resistance/Crosslinking

0 1 7 14 28

Finger Prints


XRF (X-Ray Fluorescence Spectroscopy) Identifies fillers, pigments & colorants & their sub-ingredients

High sensitivity but penetrates multiple coating layers

Allows factoring out of filler effects with IR

Can be used to identify contaminants

FT-IR (Infrared Spectroscopy) Limited usefulness within similar polymers

Can be quantitative

Can be combined will data mining tools

Well known, authoritative

Can do “archeology” with IR

Third party labs have IR records

FT-IR Example


Photomicroscopy


Copy Stand and Macro set-up Use DSLR with professional macro lens

Need extension tubes and macro-stage

High ISO rating >3200 camera

Fiber Optic illumination

Can do UV and NIR photography

Photomicroscopy


Standard Stereo Microscope w. DSLR Small DSLR/P&S with adapter tube

Used manually, but has video link

High ISO rating 3200-6400 camera

Fiber Optic illumination

Can do UV and NIR photography

Higher power CMO microscope available

Prefer trinoccular format

OEM camera also have software tools

Trapped moisture

under polyurethane

(40X)

Digital Processing


Photoshop CS6

Color balance, lens correction…

Panoramic stitching

HDR (high dynamic range)

Helicon Focus Focus Stacking (EDF)

Ultimate solution is Keyence VHX-1000

Photomicroscopy


NIR Photo, to prove color match

Camera: Nikon D-90

IR Filter: Hoya Infrared R72

Processing: Photoshop CS5

Composite Photo: 8 images

Camera: Nikon D-90

Copy Stand and Velbond Macro stage

Processing: Helicon Focus & Photoshop CS5

Photomicroscopy


Macro Photo ~4X

Underside, looking up, of blister

Camera: Nikon D-90


Macro Photo ~4X

Looking down into 45 degree cut

This is a chalking complaint

with a very thin layer of brown over white acrylic

Camera: Nikon D-90


Photomicroscopy


Macro Photo 1X, F-32

Asphalt Bleed Through

Camera: Nikon D-90

Laboratory

Flowchart


Resources


Juran, J. M. (1979). Juran’s Quality Control Handbook. (3rd ed., pp. pg.

16-32). New York, New York: McGraw Hill.

Jones, P. (2011) Practical Forensic Digital Imaging: Baton Rouge, FL

Weldon, D.G. (2009) Failure Analysis of Paints and Coatings: West

Sussex, UK

Golton, W.C. (1992) ASTM STP1110 Analysis of Paint and Related

Materials: Current Techniques for Solving Coatings Problems.

Philadelphia, PA

Hamburg H.R. (1979) Hess Hess's Paint Film Defects, Their Causes and

Cure, (3rd Edition)

Koleske, J.V. (2012), Paint and Coating Testing Manual, 15th Edition of

the Gardner-Sward Handbook - ASTM MNL17-2ND: Philadelphia, PA


Questions


Steven Heinje Technical Service Manager

Quest Construction Products

United Coatings • Hydro-Stop • StreetBond

[email protected] 509.991.0752 • 509.443.5525

Thank You

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