applying condition based monitoring approach in engineering management services
TRANSCRIPT
Applying Condition
Based Monitoring
Approach in Facility
Management Services by
Ismail Yusof
CONTENTS
Maintenance Strategies
Condition Based Maintenance (CBM)
Condition Based Maintenance Cycle
Spectrum of CBM
Detection Method in CBM
Mortality of Machinery & Bathtub
Type of CBM
IR/VA/OA/PQA/US
Benefits
The Challenges
MAINTENANCE
STRATEGIES
Maintenance
Reactive
Maintenance
Unplanned
Preventive
Maintenance
Planned
Condition Based
Maintenance
Condition Based
Condition Based
Maintenance
A predictive approach can be applied to any equipment problem if,
A physical parameter like vibration, temperature,
pressure, voltage, current, or resistance can be measured.
An engineering limit for the measured physical parameter must be, established so a problem can be detected during routine monitoring.
The limit should be low enough to detect the problem before excessive damage occurs. Correcting of the root problem is the key to most predictive efforts.
Condition Based
Maintenance Cycle
yes
Analyze Problem
Open Corrective
Work Order
Corrective
Maintenance (Schedule)
Condition Based or Periodic
Monitoring
no
Spectrum of CBM
With CBM technology, a vast number of
equipment failures can be predicted.
Vibration measurement on rotating equipment
& InfraRed Thermography is probably the best
known of current CBM applications, but other
categories of industrial equipment also benefit
from a CBM approach.
Detection Method in CBM
Spectrum of CBM
Equipment
Category
Equipment
Types
Failure Mode Failure Cause Detection
Method
Rotating Machinery Pumps, Motors,
Compressors, Blowers
Premature Bearing
Loss
Excessive Force Vibration and Lube
Analysis
Lubrication Failure Over, Under,
or Improper Lube; Heat
and Moisture
Spectrographic &
Ferrographic Analysis
Electrical Equipment Motors, Cable,
Starters, Transformers
Insulation Failure Heat, Moisture Time I Resistance
Tests, IR Scans and
Oil Analysis
Corona Discharge Moisture Splice
Methods
Ultrasound
Heat Transfer
Equipment
Exchangers,
Condensers
Fouling Sediment I Material
Buildup
Heat Transfer
Calculations
Containment and
Transfer Equipment
Tanks, Piping,
Reactors
Corrosion Chemical Attack Corrosion Meters,
Thickness Checks
Stress cracks Metal Fatigue Acoustic Emission
The mortality of machinery
There is a definite pattern of life spans. In practice, this pattern manifests itself when a collection of machinery is subjected to rigorous operation. The plot of typical life spans is shown in the so-called bathtub curve.
There is a rather high incidence of early failures, called infant mortalities. Most equipment that survives infancy will continue to perform with few failures occurring. In time, however, the failures begin to increase until the last of the group succumbs.
Bathtub Curve
Machine
Failures
Machine Life - Years
Random Failures
Normal Aging
Infant Mortalities
Type of Condition Based
Maintenance
o Infra Red Thermography
o Vibration Analysis
o Oil Analysis
o Power Quality Analysis
o Ultrasound
InfraRed Thermography (IR)
Infrared thermography, thermal imaging, thermographic imaging, or thermal video, is a type of infrared imaging science. Thermographic cameras detect radiation in the infrared range of the electromagnetic spectrum (roughly 900–14,000 nanometers or 0.9–14 µm) and produce images of that radiation, called thermograms.
Since infrared radiation is emitted by all objects near room temperature, according to the black body radiation law, thermography makes it possible to "see" one's environment with or without visible illumination.
The amount of radiation emitted by an object increases with temperature, therefore thermography allows one to see variations in temperature. When viewed by thermographic camera, warm objects stand out well against cooler backgrounds; humans and other warm-blooded animals become easily visible against the environment, day or night. As a result, thermography's extensive use can historically be ascribed to the military, security services and Condition Based Maintenance.
Sample of IR Images
Sample of IR Images
33.3°C
151.5°C
40
60
80
100
120
140
SP01
AR01
AR02
LI01
LI02
SP02
50
100
150
Line Min Max Cursorli01 37.6°C 125.9°C -li02 36.2°C 58.9°C -li03 - - -
°C IR01
Infrared Image Photo
Thermal Profile
VIBRATION ANALYSIS (VA)
Vibration refers to mechanical oscillations about an equilibrium point.
The oscillations may be periodic such as the motion of a pendulum or
random such as the movement of a tire on a gravel road
Rotating machinery has a characteristic vibration pattern depending on
the location the vibration data is collected. Characteristic vibrations are
produced at different frequencies for similar equipment.
Any change to these vibration patterns will indicate the nature and
severity of a defect such as misalignment of shafts, bearings and footing
etc. In vibration analyses a transducer converts mechanical motion
(vibration) to electrical signals.
These electrical signals are then plotted on amplitude versus frequency
plots, which then is analyzed to predict the source of vibration.
Defining VA Limits
Many engineered limits have already been established for equipment by manufacturers, professional societies and industrial groups.
Vibration Institute, a not-for-profit professional organization, and other organizations have established levels of equipment health as a function of vibration velocity based on experiments.
A simplification of this equipment health data for ‘Rotating machinery ratings.‘ This table is useful for categorizing vibration levels on most industrial equipment operating between 600 rpm and 3600 rpm.
Vibration Limits
Rotating Machinery Ratings
Rating Vibration Level Necessary
Action
Good Less than .15 ips Continue to trend
Fair .15 ips to .30 ips Continue to trend
Poor .30 ips & above Analyze & Correct
Using Ultrasound & Vibration
In the past, ultrasound and vibration technologies
have been used independently to monitor ball
bearings in plant equipment.
However, it is becoming more common to use
ultrasonic inspection interfaced with vibration
analysis to support CBM maintenance programs for
periodic inspection of critical bearings to monitor
wear and predict failure.
Using Ultrasound & Vibration
Oil Analysis
Oil analysis (OA) is the sampling and laboratory analysis of a lubricant's properties, suspended contaminants, and wear debris.
OA is performed during routine preventive maintenance to provide meaningful and accurate information on lubricant and machine condition. By tracking oil analysis sample results over the life of a particular machine, trends can be established which can help eliminate costly repairs.
The study of wear in an machinery is called tribology. Tribologists often perform or interpret oil analysis data. The sample sent to Accredited Lab for analysis.
Oil Analysis
OA can be divided into three categories:
Analysis of oil properties including those of the
base oil and its additives.
Analysis of contaminants.
Analysis of wear debris from machinery.
Oil Analysis
Comparing the OA results of new and
used oil, a tribologist can determine when
an oil must be replaced.
Careful analysis might even allow the oil to
be "sweetened" to its original additive
levels by either adding fresh oil or
replenishing additives that were depleted.
BENEFITS OF APPLYING
CONDITION BASED
MAINTENANCE
Increase Your Profitability by:
• Reducing capital costs.
• Reducing maintenance costs.
• Reducing energy costs.
Reduces the risk of:
• Costly business interruption.
• Fire/ life safety.
• Code violations.
The Challenges Ahead !!!!
First and most important of all, the initial cost of CBM is high. It requires improved instrumentation of the equipment. Often the cost of sufficient instruments can be quite large, especially on equipment that is already installed.
Next introducing CBM will invoke a major change in how maintenance is performed, and potentially to the whole maintenance organization in a company. Organizational changes are in general very difficult.
The technical side of it is not always as simple. Even if some types of equipment can easily be observed by measuring simple values as vibration (displacement or acceleration), temperature or pressure, it is not trivial to turn this measured data into actionable knowledge about health of the equipment.
Also Limited Maintenance/resources budgets (insufficient manpower, tools, training and skilled staff).
Lastly Obsolete systems & equipment.