CLS Risk Assessment & Mitigation 3 — Questions and Answers
Question 1: In a condition-based maintenance program, what is the primary purpose of establishing alarm limits for oil analysis parameters?
- To determine the correct lubricant viscosity grade
- To trigger timely corrective action before catastrophic failure occurs (Correct answer)
- To calculate the exact remaining useful life of the lubricant
- To comply with ISO cleanliness codes
Correct answer: To trigger timely corrective action before catastrophic failure occurs
Alarm limits signal when oil analysis results deviate enough from baseline to warrant investigation or corrective action before failure occurs.
Question 2: Which type of bearing failure is most commonly associated with lubricant starvation risk?
- Spalling from subsurface fatigue
- Adhesive wear and smearing (Correct answer)
- Fretting corrosion from micro-motion
- Electrical pitting from stray currents
Correct answer: Adhesive wear and smearing
Lubricant starvation removes the protective film, causing direct metal-to-metal contact and adhesive wear (smearing) on rolling element surfaces.
Question 3: What is the PRIMARY risk when lubricants from two different suppliers are mixed in a reservoir without compatibility testing?
- Viscosity becomes too high for the application
- Additive packages may react adversely, causing precipitation or foam (Correct answer)
- The base oil oxidizes immediately upon mixing
- ISO cleanliness code automatically worsens
Correct answer: Additive packages may react adversely, causing precipitation or foam
Different additive chemistries can react when mixed, potentially causing sludge, precipitation, foam, or loss of critical protective properties.
Question 4: A facility stores lubricants in an unheated outdoor area. Which environmental risk poses the greatest threat to lubricant quality?
- Excessive heat causing base oil evaporation
- Water condensation inside containers from temperature cycling (Correct answer)
- UV radiation degrading lubricant additives
- Wind-driven dust contaminating closed containers
Correct answer: Water condensation inside containers from temperature cycling
Temperature cycling causes air inside containers to expand and contract, drawing in moist air that condenses as water contamination inside the drum.
Question 5: When evaluating the risk of grease over-lubrication in electric motor bearings, what is the most likely consequence?
- Bearing corrosion from displaced grease additives
- Overheating due to churning losses and potential insulation damage (Correct answer)
- Increased bearing fatigue life from extra cushioning
- Reduced operating noise from grease dampening
Correct answer: Overheating due to churning losses and potential insulation damage
Excess grease causes churning, which generates heat that can overheat the bearing and damage motor windings if grease contacts them.
Question 6: Which document is the primary risk reference for identifying hazardous properties of a lubricant, including flammability and health exposure limits?
- Lubricant Technical Data Sheet (TDS)
- Safety Data Sheet (SDS) (Correct answer)
- ISO 15243 bearing failure analysis standard
- Equipment OEM lubrication manual
Correct answer: Safety Data Sheet (SDS)
The SDS (formerly MSDS) contains required safety information including flash point, toxicity, exposure limits, and emergency response procedures.
Question 7: What lubrication risk is specifically assessed by measuring the dielectric strength of an insulating oil?
- Oxidation stability under thermal stress
- Ability to withstand electrical stress without breakdown (Correct answer)
- Water contamination from atmospheric exposure
- Additive depletion from extended service
Correct answer: Ability to withstand electrical stress without breakdown
Dielectric strength measures the voltage at which an insulating oil fails electrically, with water contamination being the most common cause of reduced dielectric strength.
CLS Risk Assessment & Mitigation 3
In a condition-based maintenance program, what is the primary purpose of establishing alarm limits for oil analysis parameters?