Chapter 6: Value Engineering

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REVIEW EXAM 3
NOTE This is a summarized Review of the
material considered for Exam 3. It is just to
help you in your preparation for the exam. You
are suppose to complete these notes with your
class notes, and the book. For questions please
contact me (Weil 415)
Dr.
C. Cardenas
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Ch-20 CONTROLS
6 Guidelines
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I) Select the Proper Type of Control

• Control Systems
• Types of Controls

II) Select Proper Control Characteristics

• Force - People Variables
• - Control Variables
• Keys on Pushbuttons
• Cranks
• Knobs
• Hand Wheels
• Foot/Leg Controls

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III) Prevent Unintended Activation

• Key or Special Tool Activation (Locks)
• Interlocks
• Barriers or Covers
• Recessing
• Spacing
• Resistance
• Direction

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IV) Prevent Incorrect Identification

• Labeling
• Color
• Shape
• Size
• Mode of Operation
• Location

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V) Make Accomplishments Intentions
VI) Properly Locate Arrange Controls

• Location
• - Foot Controls
• - Hand Controls
• Arrangement

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Ch-21 DISPLAYS
Active and Passive Displays
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I) Why are they IMPORTANT ?

• Cannot Afford Failure
• to Communicate
• Legibility or Detectability
• Contrast, Size
• Understanding Problems (the Display)

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II) Select Legible Characters
Communicate Communicate
III) Arrange Characters and Symbols

• Optimum Height
• - Manipulative Work 50mm below elbow
• - Non- Manipulative Work Not that clear
• Soluton Techniques
• - Change Machine Height
• - Adjust Elbow Height
• - Adjust Work Height on Machine

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IV) Decide Among Menus, Formulas, Tables,
Graphs and Symbolic Message

• Justification / Selection
• Chair Design
• - Seats
• - Backrests
• - Armrests
• - Legs / Pedestal
• Non-Chair Alternatives
• Seating Posture Variability

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V) Project Your Message

• Power
• Control

VI) Select the Instrument Display

• Body
• Work

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VII) Locate / Arrange the Display

• Stirring and Polishing Motions
• Baking, Flour Making, Polishing
• Disposal Motions
• Improve performance, minimize
• Acceleration/Deceleration deviations
• Grasping Motions
• Improve grasping can Min. Acel/Decel
• Transport Motions
• Extra time extra effort to transport weight

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Ch 22 Eye Illumination

• Near Point
• The closest point at which you can focus
• Decreases with age
• Work should be done at over twice the near point
• Changing from bright to dark or vice versa
• Requires adjustment time
• Visual acuity (ability to distinguish detail)
• 1/(Visual angle of minimum detectable object)
• 20/20 gt you see at 20 feet what the normal
  person sees at 20ft.

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Eye ... (cont.)

• Dynamic visual acuity (moving target)
• Is important for some inspection tasks
• Rods and Cones
• Rods- darkness, black/white
• Cones- daylight, color
• Contact lenses in poor environment, safety
  glasses for different environments

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Principles of Efficient Lighting Design

• Meet target light levels
• Efficiently produce light
• Efficiently deliver light
• Automatically control lighting operation

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Factors in Successful
Lighting Applications

• Amount of light required
• Energy efficiency- efficacy (lumens/watt)
• Lumen output of lamps and fixtures
• Color rendition CRI
• Color temperature
• Types of light sources
• Lighting quality

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Color Temperature Scale
warm ? cool low ? high
Make sure to match color to temperature lighting
to application
Color temperature of a lamp describes the
appearance of the light generated compared to the
perceived color of a blackbody radiator at that
temperature on the absolute temperature scale
(Kelvins)
Low K
high K
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Amount of Light Needed For Specific Applications

• In general, we use far more light than necessary
  for many applications and tasks
• Light level are measured in Footcandles, using a
  Footcandle meter that is relatively inexpensive
• Acceptable minimum standards of light levels are
  set by the Illuminating Engineering Society (IES)

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Some Typical Light Levels Needed

• Parking lot 2
  Footcandles
• Hallways 10 Footcandles
• Factory floor 30 Footcandles
• Offices 50
  Footcandles
• Inspection 100 Footcandles
• Operating room 1000 Footcandles

Lamp Types
Incandescent, Halogen incandescent,
Fluorescent, Compact fluorescent, Mercury Vapor
(MV), Metal Halide (MH), Compact MH, High
Pressure Sodium, Low Pressure Sodium
(orange), etc.
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Ch 23 Ear Noise

• Hearing loss
• Similar to CTD
• Noise reduction
• Masking noise fountains, A/C, music, fans
• Reducing noise
• Plan ahead
• Modify existing noise source
• Modify the sound wave
• Use personal protection

Decreasing desirability
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Solution

• Plan ahead
• a) Substitute less noisy processes
• b) Purchase less noisy processes
• c) Use quieter construction/materials (impact,
  vibration, turbulence, transmission)
• d) Separate people and noisy equipment

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Solution (Cont.)

• Modify existing noise source
• Modify the sound wave with sound absorbers
• Use personal protection
• (Time, Equipment like ear muffs/plugs)

Noise

• Hearing tests- tested with audiometer
• Hearing loss can be temporary) or permanent
• affected by age, virus, and noise

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Noise (cont.)

• Definition Sound pressure level (SPL)
• P sound
  pressure of the noise N-m2
• Po reference
  sound pressure level
• 0.000020 N-m2
  0dB

Minimum 20 N-m2 (approx. hearing level of a
young person with unimpaired hearing)
Power level of noise (PWL) Power watt
level W
Acoustic power of noise, watts
Wo Reference power
level 1 x 10 12 watts Since 1 x 10 12
120 dB we can rewrite PWL 10
log W 120 Thus, 120 dB of power 1 W
Notice that two sources of sound are not
additive directly!! 2 machines at 80 dB 83
dB (doubling only adds 3 dB)

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Noise (cont.)

• Noise can interfere with speech. This can be
  address at 4 stages
• The messenger
• The speaker
• The transmission system
• The listener
• Use of international aviation alphabet

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Sound

• Frequency in Hz
• Low frequency sound (20Hz) has long wavelengths
  (17 m.)
• High frequency sound (20,000Hz) has short
  wavelengths (1.7 cm.)
• Long wavelengths turn corners and go through
  opening
• Short wavelengths do not turn corners.
• Sound measurement scale used (dBA)
• Dosimeter give exposure over a period

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Chapter 24 CLIMATE
Indoor Air Quality (IAQ)

• Energy and insulation improvements,
• building air quality has degraded
• IAQ sometimes exceeds EPAs guidelines
• Outdoor air quality..

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Symptoms of AQ Problems
Indoor Air Quality (IAQ)
IAQ standards for Industrial applications only.
No residential or commercial standards exist

• Periodic / Chronic Exposure
• Headaches, allergies, coughing
• Irritation membranes nose, mouth, throat, lungs
• Tearing, redness, and irritation of the eyes
• Mood swings, fatigue, irritability
• Examples .

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Symptoms of AQ Problems
Chronic Exposure Permanent damage liver, kidney,
lungs brain More severe cancer, death

• Carbon monoxide, methane cannot be detected
• without special equipment.
• Others Cyanide, Sulfhydric Acid, Polysulfurs,
  
• Dangerous particulates asbestos fibers (20 yrs)
• They cut Cellular Respiration

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Ventilation
ASHRAE standards include air, odor, vent
volume Insufficient ventilation sick building
syndrome
Interior pollutants are not dispersed Examples
car exhaust, cigarette smoke, etc.

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Solution

• Reduce Air-borne contaminants and
• exposure to the contaminants
• Provide Proper ventilation

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Solution
Area Ventilation Example semiconductors
manufacturing facilities Local Ventilation Example
the exhaust air from the office can be part of
the supplier air to a paint booth or dryer oven
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Comfort

• HVAC to maximize human thermal comfort
• Establishing a heat balance between the occupant
• and his/her environment
• Body Heat Exchange
• Human body heat rate dissipation

Psychometric Charts
Comfort is divided into 7 major factors
Can you find them tell what are they ?
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Compensating Factors

• Clothing Activity
• Air Velocity Mean radiant temperature
• Time of exposure Time of Day, Season of year
• Gender and Age of occupant

Heat Stress

• Heat effects are measured officially by body core
  T
• Example Alpinists ability to solve simple
• algebraic problems at high
  altitudes

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Reduction of Heat Stress

• Homeostasis Body Automatic Thermo-regulation
• Hypothalamus body setpoint
• The difference can cause sweating, shivering,
  blood vessel vasodilatation
• Work, Metabolism, Clothing can affect.

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Cold Stress

• Cold gives loss of mental performance and
  decreased mental dexterity (alpinists)
• Wind Chill Index Combined effect measurement of
  air velocity and temperature
• Clothing the primary defense against cold stress.

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Chapter 25 TOXICOLOGY
Deals with the long term effects of foreign
chemicals on the body Depends on - type
and amount - critical or
cumulative Response might not be immediate
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Poisons

• Threshold Limit Values (TLVs)
• To establish if effects are reversible or not
• TLVs are directly proportional to body mass

Poison Delivery Routes
Skin compromised with open cuts
/abrasions Mouth Forbid eating / drinking /
smoking in a work area to avoid
ingestion Lungs Size determines what is
inhaled, retained. Small particles are more
dangerous
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Toxicology Controls

• Via Eng., Admin., or Personal protection
• Substitute a less harmful material
• Water base instead of organic base cleaning
  compounds
• Avoid volatile compounds
• Change the material or process
• Use safety cans instead of glass bottles
• Use vacuum cleaner instead of compressed
  (blowing)
• Wear safety glasses

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Toxicology Controls

• Enclose (Isolate) the process
• Vapors
• Enclose Operations (gluing, painting)
• Use Wet Methods
• Use high pressure water jet instead of abrasive
  blasting for cleaning operations
• Use moistened flint in potteries

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Toxicology Controls

• Provide local ventilation
• Input air - worker - contamination - exhaust air
• Eliminate fumes from work place
• Allow local ducts
• Provide general (dilution) ventilation
• Use general ventilation
• Forced ventilation

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Toxicology Controls

• Use Good House Keeping
• Remove dust - Eliminate chemicals (drums) - Clean
  up spills
• Control Waste Disposal
• Have safe waste disposal - Separate
  hazardous/nonhaz
• Storage area should be fail-safe

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Toxicology Controls

• Screen Potential Employees
• Hypersensitivity to a particular substance
• Screening out cigarette smokers from exposure to
  asbestos
• Periodically examine employees
• Train the supervisors, engineers, and workers
• Reduce exposure time

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Toxicology Controls

• Personal Protection
• Completely sealed body suit and hood (paint
  booth)
• Discard saturated clothing
• Clean-up systems run empty cycle with hot
  detergent
• Example Softdrink bottling companies (Pepsi,
  Coke, etc.)

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Ch 26 Safety
Deals with accidents and injuries Accidents
Spectrum Non hazardous Hazardous
Near Acc. Accidents
Lost day / Injuries
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Injury Rate

• Injury Rate (IR) I (200,000) / yr
• Where
• IR Annual injury rate / 100 employees
• I Injury cases / yr
• 200,000 40 hrs / week 50 weeks / year 100
  employees
• IRs are reported to OSHA compared by SIC
  (Standard Industrial Classification) code

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Management Approach to Safety

Pareto - Where remedial work to be
focussed Other reasons for Accidents - Unsafe
conditions (equipment failure) - Unsafe Acts
(human failure) make them safer
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Approaches to Fixing
Safety Problems

• Design out the problem
• Design the proper control mechanism
• Use Distance - Separate hazard from people
• Use guards - mechanical (splash, sensors)

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Unsafe Acts

• Safety training Key to reducing unsafe acts
• Avoid decisions that cause undertake risk
• Use incentives to encourage safety
• Remember error reduction (Chapter 12)