Title: Safety Concerns for Vibration Testing
1Safety Concerns for Vibration Testing
Ray Kelm, P.E. Kelm Engineering Danbury, TX
Presented at Vibration Institute Michigan Annual
Seminar
2Why be Safe?
Youve got too much to lose!!!
3Oops!!
4Do Accidents Happen?
- Accidents that can injure people doing vibration
testing can be a result of - Unnecessary exposure to damaged equipment
- Plant upsets
- Sudden failure without warning
- Lack of guarding or covers
- Stupidity and/or ignorance of the analyst
- Fatigue from being overworked and overstressed
5Personal Experience
- Have you ever been injured?
- Cuts on sharp objects
- Burns from hot surfaces
- Twisted ankle and/or climbing injuries
- Bruises/lacerations
- Back injury from carrying heavy equipment
- High noise/hearing loss
6Can Injuries be Prevented?
Injury and Illness Rate for Workers in Private
Industries Injuries and Illnesses per 100 Workers
Bureau of Labor Statistics Recordable Injury
Rates for US Private Industries
7How do we Prevent Injury
- Many petrochemical plants in the US have OSHA
recordable rates in the 1.0 and lower range - US area safety culture
- Take care of yourself
- Take care of your fellow workers
8Safety Culture Concept
- How you work at home or when nobody is looking is
your normal culture - Acting in a Safe way is often a matter of
personal choice and priority
9When are We at Risk?
- Special testing with guards removed
- Required vibration testing/analysis when
equipment has severe vibration - Testing during plant startup or upsets occur
10Purpose of Talk
- Openly discuss Safety Concerns for Vibration
Analysts - Raise concern by those doing testing to risks
they may not already be aware of - Make us all think and raise general awareness
levels
11How to Reduce Injury Potential
- Eliminate the risk altogether
- Equipment design changes
- Procedural changes
- Training and Accountability of Personnel
- Basic and specific safety training
- Accountability for safety violations
- Review of injuries and corrective actions
12Eliminating the Risk
- Frequently heard the slogan in plants
- we will do it safely, or we wont do it
- Sometimes seen in action
- we will do it safely, unless it is too
expensive or will have too big an impact on
production
13Main Approach to Eliminating Risk
- Provide Engineering Controls to Reduce or
Eliminate Risk - Train Personnel and use Written Procedures
- Limit Human Exposure to High Risk Areas
- Use PPE as a Last Resort
14Eliminating the Risk - Design
- 100 Enclosure of Rotating Shafting
- Bearings/shaft ends
- Couplings
- Exciters/slip rings
- Sheaves and belts or chains
- Use of Acoustic Enclosures (doghouses)
15Eliminate With Design cont.
- Install Permanent Sensors with Cables Routed to a
Lower Risk Area - Soft Start or Variable Speed Drives
- Addition of Recycle Lines to Unload at Startup
- On-Line Surge Control Systems
- Additional Controls for Plant Upsets/Startup
16Guarding Of Equipment
- What is the purpose of a coupling guard?
- Climbing platform?
- Debris containment in case of coupling failure?
- Oil leak reduction?
- Complete enclosure?
- OSHA guard is required to prevent contact of
rotating/reciprocating components by body parts
and or clothing during normal operation
17Risks with Guards
- Sensors/cables near exposed rotating shafting
when guards are installed - Use of break away shoulder straps?
- Frequently the guards are left removed during
testing - Exposed shaft for temporary tach
- So coupling can be looked at with a strobe
18High Noise Areas
- Vibration Test is Frequently Done in High Noise
Areas - Turbines
- Compressors
- Control Valves (particularly during startup)
- If you have to raise your voice, you need hearing
protection
19Acoustic Enclosures
- Nice Idea for New Installations
- Horrible for Maintenance
- Generally of little value to Vibration Analysts
since we end up having to open the enclosure to
get vibration readings directly on the casing of
the noisy machine - Sound attenuation deteriorates over time
20Permanent Sensors
- Vibration sensors can be routed to safer areas
- Great idea, but generally wont get enough sample
points except for basic trending - Cost may be gtgt1,000 per point
21Plant Startup Methods
- Reduction of high starting transients
- Variable speed drives
- First start after overhaul
- Wear in of seals
- Full recycle starting process
- Review of starting process to make sure equipment
is not abused
22On-Line Controls
- Overspeed Protection
- Surge Control
- Centrifugal Compressors
- Axial Compressors
23Managing Risk - Training
- Little available training material is available
that is specific to vibration analysis - Unguarded equipment
- Climbing with test equipment
- Hazardous/Flammable chemical exposure
- Fatigue
- Spark/explosion potential with test equipment
24Contact of Rotating Shafting
Nature of injury Number Percent
Total 34,350 100
Cuts, lacerations 11,177 32
Amputations 4,832 14
Fractures 4,376 13
Bruises, contusions 2,920 8
Multiple injuries 2,401 7
With fractures 1,018 3
With sprains 191 1
Sprains, strains 1,077 3
Soreness, pain 426 1
All other 7,129 21
Table 1 - Nonfatal injuries involving days away
from work resulting from workers being caught in
machinery, private industry, yearly average,
1992-96. 3
25Fatalities from Caught in Machinery
Work Activity Number Percent
Total 189 100
Operating machine 85 45
General (unspecified) repair Or maintenance 37 20
Unjamming materials 19 10
Cleaning machine 14 7
Adjusting Machine 8 4
Reaching or stepping over machine 7 4
Inspecting or checking machine 5 3
Other 14 7
Table 2. Activity performed by workers fatally
caught in machinery, 1997 3
26Wrapped Around Shaft
- 11 deaths in 1997 due to clothing wrapped around
shaft - Incidents of hair entangled causing scalping and
facial disfigurement - Guards are often not fully protecting against
contact with shafting
27Safe Use of Cables
- Loose cables around rotating shafting should be
prevented - Keep cables free of slack
- Consider coiled cables when appropriate
- Always keep one hand on the sensor (magnetic
mounted)
28Safe Sampling Technique
- Approach the machine and determine the
appropriate location for mounting of the sensor. - Hold the sensor in one hand while holding the
cable in the other hand that is used to press
buttons on the analyzer. - Always keep slight tension on the cable from the
analyzer to the sensor while the magnet is
mounted onto the casing.
29Safe Sampling, cont.
- Keep the sensor hand on/near the sensor to
prevent the magnet from coming loose and the
sensor possibly falling onto the rotating
shafting (magnet could stick to rotating shaft
and pull in the cable). - Continue to hold slight tension at all times on
the cable with the hand near the monitor device
while operating the controls on the box. - When sampling is complete, remove the sensor and
maintain tension on the cable until the cable and
sensor are clearly out of contact with the
machinery.
30Safe Sampling, cont.
- Keep the cable coiled (opposed to hanging down)
at all times when walking from one sample point
to the next. - If multiple sensors are mounted for extended use,
tie down the cables to prevent them from
contacting any rotating (or hot) components.
31What NOT to Do
- NEVER attempt to stop a rotating machine during
coastdown by touching the shaft or pressing a
foot against the rotating shaft to speed up
inspection or balancing activities. - The only devices that should ever be considered
to stop a rotating machine are those that are
specifically engineered for such a purpose. This
specifically excludes 4x4 wood blocks, ropes,
etc. - Any machine that will not stop turning for
inspection or balance weight addition such as a
fan with draft causing the wheel to continually
spin after shutdown, should be properly isolated
to stop the draft to allow the machine to come to
rest on its own.
32What NOT to Do (Contd)
- NEVER attempt to use a shaft rider on a shaft
that has not been verified by inspection to be
free from keyways, keys or other features that
could cause the rider to jump back from the
shaft. - NEVER attempt to temporarily install a sensor
underneath a coupling guard (to get the load zone
on a bearing in the axial direction) unless
contact with the rotating shafting can be
prevented and clear visual contact of the sensor
and cable can be maintained at all times.
33What NOT to Do (Contd)
- NEVER touch a shaft unless the machine has been
verified to be appropriately locked out. - Dont use an instrument strap around rotating
machinery to hold up the vibration analyzer that
does not have a break-away feature to prevent the
user from being pulled into equipment by the
sensor cable.
34Climbing Ladders and Stairs
- It is often necessary to climb ladder cages
and/or stairs to get the levels where equipment
is mounted - Hands should always be kept free to hold onto the
ladder or at least one hand rail on stairs - NEVER climb a ladder while holding vibration
measurement equipment in either hand or under
arms. - NEVER climb stairs with both hands holding test
equipment or other items. Always keep one hand
on the handrail.
35Safe Climbing
- Use a carrying strap purchased from the
monitoring equipment vendor to carry the
monitoring device without using hands. - The strap should be provided with some sort of
break away device (Velcro or other similar) in
the event that the sensor or cable did get
wrapped around a rotating shaft to prevent being
pulled into the equipment. - Consider wearing a holster or other holding
device (could be a pocket in shirt/pants) to
store the sensor and cable in while climbing.
36High Noise Areas
- Areas are classified using normal operation
noise surveys - Any unusual operation (startup, etc) may cause
higher noise levels - If you have to raise your voice to talk, wear
hearing protection
37Hearing Protection
- Ear plugs have marked NRR (noise reduction
rating) - Published ratings should be reduced per OSHA
guidelines by at least 7 dB - Muffs with NRR23 are acceptable up to a noise
level of 85 23 7 101 dBA
38Chemical Exposure
- Vibration personnel are often called out to check
vibration on equipment with known faults - High vibration can easily result in seal failures
- Analysts are at much greater risk of chemical
spray due to possible seal failure
39Spray Area
40Reducing Potential Chemical Exposure
- Always take note of the wind direction prior to
approaching the machine, and approach from the
upwind side. - In the case where the equipment is located on an
elevated platform, climb stairs or a ladder cage
on the upwind side - As a minimum verify that egress can be made from
the upwind side. - Take note of the nearest safety shower prior to
approaching the machine. - NEVER stand perpendicular to the shaft at a
process seal.
41Reduce Exposure (Contd)
- If the machine becomes unstable or the
noise/vibration becomes dramatically more intense
while standing next to it, stop vibration
sampling and exit the area on the upwind side. - As a minimum, stand on the upwind end of the
machine until transient events stop. - NEVER enter an area around a machine that has
suspected faults and walk around to the side of
the machine where you have no route of escape
from. - In the event of failure, you should always have
an unobstructed route of escape.
42Reduce Exposure (Contd)
- Spend a minimum amount of time near the machine
with the possible fault, and in cases where the
risk of chemical exposure is higher (lethal or
explosive products). - Always mount sensors and use longer cables so
that the risk is reduced by simply placing your
body further away from the source of the
potential leak. - NEVER attempt to record vibration data on a pump
that is leaking or slinging liquid due to a seal
leak or other damage unless contact with
potentially hazardous materials can be prevented.
43Reduce Exposure (Contd)
- NEVER congregate or linger around machinery that
may have mechanical damage or is being misapplied
(surging compressor, deadheaded pump, etc.). - Take vibration readings and make visual
observations in the shortest time possible, then
leave the area. - If other personnel are in the area, recommend to
them that non-essential people leave the area.
44Fire Fighter Mentality
- I am the hero
- I must go into the battle to save the plant
- I have to hurry because the plant may shut down
or the machine may fail before I get my data
The Vibration Analyst Should ALWAYS Reserve the
Right to NOT Take Data!!
45Plant Upsets
- ALWAYS be aware of possible plant upsets that may
warrant leaving the area - During a compressor surge
- When relief valves are popping
- If pipes are jumping in the pipe rack due to
waterhammer or other surging
46Hot Surfaces
- Insulation is normally provided for surfaces over
140?F - Some hot parts are NOT insulated
- Steam turbine valves or casing
- Hot process piping instrument connections
- Piping or tubing for steam tracing
- Support feet on gas turbines
- Exhaust piping from engines
47Fatigue
- Fatigue occurs due to a combination of long work
hours and high stress - Most plants limit work hours to 16 hours per 24
hour day - This limit must be reduced when continuing for
more than several days - Anxiety due to plant startup and field balancing
efforts can greatly increase fatigue levels
48Preventing Fatigue Exposure
- Use multiple people when taking vibration
measurements so they benefit from the awareness
of two people instead of one - Take extra time to discuss safety concerns
between the two people involved in the
measurements - Take frequent breaks, and drink plenty of water
49Non-Intrinsically Safe Equipment
- Most data acquisition equipment is NOT
intrinsically safe - Those that claim to be, are rated with a Class 1,
Division 2 rating at best (normally not US
standard) - OK if gas is not present
50Instrument Safety Comments
- Class 1, Division 2 - This would be an area that
can have flammable concentrations of material in
the event of mechanical failure of components,
but would normally be free of combustible
mixtures. This classification would also be
required for areas adjacent to a Class 1, Div. 1
area and by default can occasionally have
concentrations of flammable material. - Class 1, Division 1 This would be an area where
combustible mixtures of materials are or may be
found during normal operation.
51Safe Use of Instruments
- NEVER operate non-intrinsically safe instruments
in areas where the potential for flammable
mixtures may exist unless monitoring is performed
and no combustible mixtures are identified. - If conditions change so that combustible mixtures
could be present, stop work and leave the area. - When operating in classified areas, always
operate the equipment as though an explosion risk
is present. - Make all electrical connections in an
unclassified area and keep them in tact until
return to the unclassified area. Do not
disconnect sensors from the analyzer, or continue
to operate if a cable is believed to have a short
to or a connector is found loose.
52Safe Use of Instruments (Contd)
- If conditions change so that flammable mixtures
may be present (gas release etc.), do not
disconnect sensors or cables and leave the area
immediately.
53Equipment with Known Faults
- These are cases where there is high risk of a
machine failing catastrophically, possibly
blowing seals, being very hot, noisy, etc. - NEVER approach a rough machine without a clear
plan of escape and continual consideration for
minimizing exposure during testing
54Exposure to Sudden Failure
55Motor Terminal Box Explosion
56Final Thoughts
- Most safety concerns are of general nature
- Many relate specifically to vibration testing
- Most plants have no formal safety training for
vibration analysis
57NEVER Take Unnecessary Risk
- ALWAYS reserve the right to NOT measure vibration
when the situation will put you at risk. - If its vibrating that much, you will most likely
be able to identify the faults without a detailed
vibration analysis!!