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Safety Concerns for Vibration Testing

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Safety Concerns for Vibration Testing Ray Kelm, P.E. Kelm Engineering Danbury, TX Presented at: Vibration Institute Michigan Annual Seminar Why be Safe ? – PowerPoint PPT presentation

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Title: Safety Concerns for Vibration Testing


1
Safety Concerns for Vibration Testing
Ray Kelm, P.E. Kelm Engineering Danbury, TX
Presented at Vibration Institute Michigan Annual
Seminar
2
Why be Safe?
Youve got too much to lose!!!
3
Oops!!
4
Do 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

5
Personal 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

6
Can 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
7
How 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

8
Safety 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

9
When 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

10
Purpose 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

11
How 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

12
Eliminating 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

13
Main 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

14
Eliminating 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)

15
Eliminate 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

16
Guarding 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

17
Risks 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

18
High 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

19
Acoustic 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

20
Permanent 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

21
Plant 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

22
On-Line Controls
  • Overspeed Protection
  • Surge Control
  • Centrifugal Compressors
  • Axial Compressors

23
Managing 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

24
Contact 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
25
Fatalities 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
26
Wrapped 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

27
Safe 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)

28
Safe Sampling Technique
  1. Approach the machine and determine the
    appropriate location for mounting of the sensor.
  2. Hold the sensor in one hand while holding the
    cable in the other hand that is used to press
    buttons on the analyzer.
  3. Always keep slight tension on the cable from the
    analyzer to the sensor while the magnet is
    mounted onto the casing.

29
Safe Sampling, cont.
  1. 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).
  2. 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.
  3. 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.

30
Safe Sampling, cont.
  1. Keep the cable coiled (opposed to hanging down)
    at all times when walking from one sample point
    to the next.
  2. If multiple sensors are mounted for extended use,
    tie down the cables to prevent them from
    contacting any rotating (or hot) components.

31
What 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.

32
What 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.

33
What 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.

34
Climbing 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.

35
Safe 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.

36
High 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

37
Hearing 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

38
Chemical 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

39
Spray Area
40
Reducing 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.

41
Reduce 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.

42
Reduce 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.

43
Reduce 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.

44
Fire 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!!
45
Plant 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

46
Hot 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

47
Fatigue
  • 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

48
Preventing 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

49
Non-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

50
Instrument 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.

51
Safe 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.

52
Safe 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.

53
Equipment 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

54
Exposure to Sudden Failure
55
Motor Terminal Box Explosion
56
Final Thoughts
  • Most safety concerns are of general nature
  • Many relate specifically to vibration testing
  • Most plants have no formal safety training for
    vibration analysis

57
NEVER 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!!
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