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”? You’ve 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 won’t 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 won’t get enough sample points except for basic trending • Cost may be >>$1,000 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 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 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 • 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.

29. Safe 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.

30. Safe 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.

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 (Cont’d) • 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 (Cont’d) • NEVER touch a shaft unless the machine has been verified to be appropriately locked out. • Don’t 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 NRR=23 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 (Cont’d) • 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 (Cont’d) • 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 (Cont’d) • 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.