Intermediate Infrared Concepts and Best
Practices: Thermal Imaging in your
M aintenance Program
Sat Sandhu
Thermography Services Support Manager
Thermal / Infrared Thermography, Level III
Certified in compliance with (ASNT) SNT-TC-1A-2006
1
Agenda
• Review and introduction to Thermal imaging
• The basics of performing an inspection with an infrared camera
• Tips on how to effectively spot issues with an infrared camera
• Causes and examples of Electrical, Mechanical, Process and
Building Diagnostics
• How to tie infrared inspections into your preventative
maintenance program
2
Introduction
My name is Sat Sandhu
Welcome!
Please note, this is a short class – you will not become a
thermography expert in the next hour
3
What is infrared?
• Infrared radiation can be sensed by our skin, yet cannot be seen
by our eyes!
4
What is a Thermal Image?
• Infrared cannot be seen (but can be
sensed by our skin)
• Everything emits infrared radiation
• A camera converts the “infrared
image” to a visible picture
• Infrared allows you to “see” things that
you normally can’t
Visual image
Same image in infrared
5
How is an infrared image created?
• Thousands of IR temperature measurements taken
• Each “pixel” represents a temperature measurement
• Assigned a color value to create an image
6
How can infrared help me?
• Most electrical and mechanical
defects cause increase in
temperature
• Thermal imaging provides a fast and
clear picture of this temperature
increase
• Safety: Thermal images can be
taken while production is running
without any contact
• Anybody can take a picture!
7
Thermal Imaging Applications
•
•
•
•
•
•
Electrical
Mechanical
Process Manufacturing
Building Diagnostics
R&D
Utilities
8
Thermal Imaging Considerations
•
•
•
•
•
Ensure adequate thermal gradients
Understand thermal capacitance
Account for wind effects
Avoid angular variations
Remember heat transfers from hot to
cold
• Be aware of your surroundings
• Know when qualitative
measurements are sufficient
• Compare similar components under
similar conditions
9
Thermal Imaging Considerations
• Understand present and future loading conditions
• Inspect with highest load possible (at least 40%)
10
Heat Capacity
• Objects and materials with high thermal capacitance take time to
cool down, while objects and materials with low thermal
capacitance cool down quickly
– Air has low thermal capacity, water has high thermal capacity
Thermal capacitance can help find
the liquid level in a tank
On a flat roof, after the sun goes down, dry
insulation cools faster than wet insulation
(wet insulation has higher thermal capacity)
11
Spot Size & Resolution
How far can I see?
L1 M4
L1 M4
Distance from Camera
Spot Size & Resolution
• Larger area for
average temperature
when further away
• Distance to spot ratio
• Zoom lens decreases
spot size
13
TIPS: How to Effectively Spot Issues with
an Infrared Camera
•
•
•
•
•
•
Emissivity
Understand the equipment
Load conditions
Comparative inspections
Hot spots
Cold spots
14
What happened to my beer!?
This can of suds is ice cold straight out of the fridge. When scanned with
the IR Camera you would expect the entire image to be relatively even in
temperature and to appear “cold” in relation to the background. What is
causing the spot in the center to appear warm?
15
Emissivity!
Everything in nature emits electromagnetic
radiation. Emissivity is the ratio of thermal energy
emission of the target object, over the thermal
energy emission of a true blackbody (perfect
emitter).
The paint on the outside of this can has been worn
off in a small area. The bare aluminum has a
different emissivity than the painted aluminum. The
imager sees the bare aluminum as hotter than the
rest of the can.
TIP: Use Electrical Tape to cover a low emissive surface to
increase the emissivity and accuracy of the measurement
16
Causes of Electrical Hot Spots
• Unbalanced loads
• Harmonics (3rd harmonic current in
Neutral)
• Overloaded systems/excessive
current
• Loose or corroded connections
increased resistance in the circuit
• Insulation failure
• Component failure
• Wiring mistakes
• Underspecified components
17
Examples of Electrical Hot Spots
Hot phase
Motor Control Center
Substation
Lighting Circuit
Fuse disconnect
Buss
18
Causes of Mechanical Hot Spots
•
•
•
•
•
Bad cooling because of reduced airflow
PQ problems like unbalance, overload or 5th harmonic (voltage)
Insulation problems with motor windings
Bearing problems – lubrication, wear, tolerance
Bad alignment
19
Examples of Mechanical Hot Spots
Electric motor
Compressors - normal
Hydraulic pumps
Misaligned belt
Coupling
Roller bearings
20
Causes of Process Hot Spots
•
•
•
•
Damaged structures caused by worn pipes
Abnormal heat flow/heat gradients
Defective valves/traps
Normal tank level fluctuations
21
Examples of Process Hot Spots
Cement Kiln
Tank Levels
Steam Traps
302.2°C
300
250
200
150
119.7°C
Weld cooling
Chiller Operation
Pipe Integrity
22
Causes of Building Diagnostics Hot Spots
•
•
•
•
Roof leaks
Air Leak
In-floor heating
Missing insulation
23
Examples of Building Diagnostics Hot Spots
Roof deck moisture
Moisture
Missing insulation
In-floor heat verification
Air Leak
Attic access – air leak
24
How to Tie Infrared Inspections into your
Preventative Maintenance Program
• Trends
• Maintenance programs
• Cost Savings
• Solutions
• Build a Successful program
25
Trends in Industrial Maintenance
ECONOMICS
AWARENESS
TECHNOLOGY
Downtime is getting
more expensive –
maintenance must
do more with less
Awareness is
growing quickly
New maintenance
technologies are
experiencing mass
adoption
Companies are using maintenance best practices to reinforce
and extend their competitive advantages
26
Definitions
Reactive: “run to failure”
Proactive
Preventive (PM):
“calendar-based”
Predictive (PdM):
“condition-based”
Reliability Centered:
“asset uptime based”
The Bathtub Curve
Break In
Normal Operation
Wear Out
Casualties
Time
27
Examples of Cost Savings
1. EPRI – study of many plants in many different industries
•A comprehensive study by the Electric Power Research Institute
found:
Maintenance
practices
Cost to maintain
rotating machinery
Cost savings
Plants that are Reactive
(Run to failure)
$17/HP/Year
No savings
Plants that are
Preventive (Calendarbased)
$13/HP/Year
24% over Reactive
Plants that are
Predictive (Conditionbased)
$9/HP/Year
47% over Reactive
28
Examples of Cost Savings
2. Cost to Benefit Studies
•A large company implemented a Predictive Maintenance program on hundreds of
their motors, pumps, fans, compressors and blowers
•This program has been successful for over 25 years
•They document the cost of the program and savings they enjoy
•Savings were many millions of dollars per year
•Every 2 years they conduct a Cost to Benefit study to compare the program cost
to the documented savings
•The average Cost to Benefit ratio for the past 30 years has been over 20:1
The 6 benefits that they track include:
•Prevention of catastrophic failure due to early detection
•Ability to schedule repairs during plant shutdown periods
•Ability to order parts in advance of repairs
•Ability to repair exact fault instead of complete overhaul or replacement
•Planning of workers schedules
•Root cause analysis of recurring faults
29
Examples of Cost Savings
3. Case Study – even small companies can benefit
•Over a 16 year period, a small company transitioned from
Reactive to Preventive and then to Predictive Maintenance:
– Unplanned failures dropped to almost zero
– Maintenance budget, on the 600 critical motor/pumps, cut in half
from 10 years ago
– Pumps running twice as long before repairs are needed
– Almost all maintenance is scheduled instead of reacting to
emergencies
– Repairs planned during the day and eliminating the need for
overtime
30
Benefits of Proactive Maintenance
• Predictability: give maintenance staff time to schedule repairs
• Safety: take faulty equipment offline
• Revenue: fewer unexpected failures prevent production
stoppages that cut into bottom line
• Increased maintenance intervals: life of equipment is extended
• Reliability: anticipate the problems coming
• Peace of mind: build confidence in maintenance schedules,
budgeting, and productivity estimates
Different industries / companies will have different matrixes and targets. Which of
these benefits is most valuable to you?
31
Solution: Asset Uptime for the Rest of Us
• Ideal: Dedicated PdM or
reliability team at a large
industrial plant
• The rest of us: Small
maintenance team at mid-sized
industrial or large commercial
facility with
– People, time and budget to do
proactive work
– Uses automated
systems/CMMS
– Determines when equipment
needs maintenance to prevent
failure
– No dedicated people
– Broad responsibilities but not
the scope or budget to go full
SCADA
– Gather data by hand as the
job dictates
Technology is leveling the playing field for maintenance technicians across
facilities of all sizes: they can use the same techniques and tools to troubleshoot
as well as to inspect, log, and share – the basics of proactive maintenance
32
Program Start-up: Start Small and Grow
Don’t try to do the whole plant at once
•Start with simple machines with common problems
•Use simple check lists before moving to electronic programs
•Show success in early wins, gain buy-in and support to grow program
•Proactive maintenance measurements aren’t that different from
troubleshooting tests – only faster, easier, and no expert is needed
Simple steps
•Take “good” baseline data points – compare over time to good baseline
•Quick periodic inspections with screening tools to find problems
•Return with smart diagnostic tools – find fault and diagnose repair action
•Repair fault with smart corrective tools – fix it quickly & return to service
•Validate repair with screening tool
33
Basic Inspection Guideline
Any
Anomaly
observed?
Therma
l Image
Yes
No
Temperatures on
target, similar to
each other, and
c/f with ambient?
Yes
Equipment
on or
Loaded?
High
Temp.
difference
c/f stds.
High
Medium
Low
No
Identify the type of anomaly:
1.Hot spot?
2.Cold Spot?
3.Temp. difference between
similar components?
No Further
Action
High
Low
Equipment
on or
Loaded?
Equipment
on or
Loaded?
High
Low
Low
Schedule
inspection
under load
Extra info /
Advice
process
Repair /
Action
34
A Program Builds the Links in a Maintenance Chain
SCAN
DIAGNOSE
FIX
VALIDATE
Thermal Imager
Vibration Tester
Alignment Tool
Vibration
Tester
Problem found with
vibration meter
Problem identified &
repair recommended
Problem corrected
Machine checked
with vibration meter
Multiple tools equal more than the sum of the parts
35
Technologies & Solutions – Multiple Tools
Thermography
Mechanical
Infrared Imager
Vibration and
Alignment
ScopeMeter and
Power Quality
Insulation
Tester
Process
Tools
Best technology for
finding electrical hot
spots in switchgear &
motor controllers,
screening process
and mechanical
Best technology for
diagnosing
mechanical faults in
rotating machines.
Correct shaft
misalignment.
Troubleshoot problems
in drive and drive
output, power
distribution - uncover
energy losses &
efficiency
Assures safe
operation,
prolongs life of
electrical
systems &
motors
Troubleshoot,
commission and
calibrate
transmitters,
valves, switches,
gauges
1.
1.
2.
3.
4.
1.
2.
3.
Insulation
degradation
1.
2.
3.
2.
3.
Faulty
connections
Overheated
bearings
Tank levels
Imbalance
Looseness
Misalignment
Bearings
Electrical
Harmonics
Distortion
Load Studies
Process
Pressure
Temperature
mA source
36
Before we dismiss…
•
•
•
•
I want to see a camera?
I want to learn more about thermal imaging?
I want an IR camera?
I want to talk about my specific application?
•  We have 2 certified Level I thermographers on staff
– Ben Goodhead
– Susan Garofalo
37
Questions or Comments?
Email Nicole VanWert-Quinzi
nvanwert@ Transcat.com
Transcat: 800-800-5001
www.Transcat.com
For related product information, go to:
www.Transcat.com/Fluke