Human Factors

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Human Factors

• Rolla
• Session 4
• September 13, 2001

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EFFECT OF NOISE ON PERFORMANCE PAGE 601

• 1) UNLESS TASK REQUIRES SHORT TERM MEMORY, 95
  dBA REQUIRED
• 2) SIMPLE TASKS SHOW NO EFFECT AND MAYBE WILL
  SHOW IMPROVEMENTMUSIC IN THE WORKPLACE??

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EFFECT OF NOISE ON PERFORMANCE PAGE 601

• 3) GENERALLY NO EFFECT OF CONTINOUS LOUD NOISE
• 4) MOTOR PERFORMANCE RARELY AFFECTED
• 5) SIMPLE REACTION TIME NOT IMPAIRED IF OPERATOR
  HAS ADEQUATE WARNINGS ABOUT WHEN TO RESPOND
• 6) PROBLEMS WITH INFORMATION PROCESSION JOBS

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HANDLING NOISE PROBLEMS

• 1) CONTROL AT THE SOURCE
• ISOLATE DAMP MACHINES BUY QUIETER EQUIPMENT

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HANDLING NOISE PROBLEMS

• 2) CONTROL ALONG PATH
• SOUND ABSORPION MATERIAL
• MOVING NOISE AWAY
• ENCLOSE

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HANDLING NOISE PROBLEMS

• 3) CONTROL AT THE RECEIVER
• HEARING PROTECTION
• TWO TYPES
• A) INSERT B) MUFF
• NRR-NOISE REDUCTION RATING

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NOISE EXPOSURE SOUND LEVEL (Dba) PLUS 7 MINUS
NRR
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SPEECH

• 45 dBA FOR WEAK CONVERSATION
• 55 dBA FOR NORMAL CONVERSATION
• 65 dBA FOR TELEPHONE AND LECTURE

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SPEECH

• 75 dBA FOR LOUD NEAR SHOUTING
• 85 dBA FOR SHOUTING
• FREQUENCY OF SPEECHSEE FIGURE 7-2 PAGE 200

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SPEECH AND THE NOISE ENVIRONMENT

• PSIL PREFERRED-OCTAVE SPEECH INTERFERENCE
  LEVEL500            1000 2000 HZ AVERAGE

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SIL SPEECH INTERFERENCE LEVEL

• MEASURES 600-1200 1200-2400 2400-4800
• AVERAGES THESE VALUES

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SEE PAGE 209
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CHAPTER 8

• PHYSICAL WORK AND MMH (MANUAL MATERIALS HANDLING)

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ATTEMPTS TO MEASURE WORK

• 1) HEART RATE2) RESPIRATION RATE3) OXYGEN
  CONSUMPTION FIG 8-4 PAGE
  2334) BLOOD PRESSURE
• 5) MUSCLE EXERTION FIGURE 8-7 PAGE 236

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MEASUREMENT OF STRENGTH

• 1)    STATIC STRENGTH
• 2) DYNAMIC STRENGTH

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FACTORS AFFECTING STRENGTH

• 1)    AGE MAX BETWEEN 25-35 
• SLOW DECREASE IN THE 40S
• ACCELERATED DECREASE STARTING IN 50S

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FACTORS AFFECTING STRENGTH

• 2)    SEX ACCOUNTS FOR LARGEST DIFFERENCE
• RULE OF THUMB
• FEMALE EQUALS 2/3 OF MALE STRENGTH USE IN
  ALL STUDIES FOR MALES ONLY

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EXAMPLES OF STRENGTH DATAMOST RESEARCH DONE IN
LABS SEE PAGE 252
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MANUAL MATERIALS HANDLING TRY TO AVOID-MACHINES
CAN DO THIS BETTER
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CONSEQUENCES!!!!

• 25 OF ALL INDUSTRIAL INJURIES
• 12 MILLION LOST WORK DAYS PER
• YEAR
• ONE BILLION/YEAR IN WORKMANS
• ONE BILLION PER YEAR
• 70 MILLION BACK INJURIES

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MANUAL MATERIALS HANDLING TASKS1)    LIFTING
50 OF BACK INJURIES2)    CARRYING 3)   
PUSHING4)    PULLING 95)    HOLDING6)
THROWING 6
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IMPORTANT FACTORS FOR LIFTING TASKS1)    WEIGHT
2)    DISTANCE3)    HORIZONTAL POSITION4)   
START OF LIFT 5) FREQUENCY
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IMPORTANT FACTORS FOR CARRYING, PUSHING AND
PULLING TASKS1)    DISTANCE2)    WEIGHT3)   
FREQUENCY4) POSITION
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HOMEWORK HAS BEEN POSTED READ CHAPTERS 8 AND 9
AND APPENDIX C