SENG 321670 - Home Work 2
.pdf
School
Texas A&M University**We aren't endorsed by this school
Course
SENG 670
Subject
Mechanical Engineering
Date
Dec 20, 2024
Pages
6
Uploaded by abidali675569
P a g e | 2 3.1 Name the four categories of seriousness of hazards as recognized by OSHA. OSHA recognizes four categories of hazards on other way call standards violations, which are. 1-Imminent danger 2-Serious Violations 3-Non-Serious Violations 4-De-Minimis Violations OSHA also defines subjectively four types of hazards on 10-point scales (Table 3.1), which are. 1-Fatalities 2-Health Hazards 3-Industrial Noise hazards 4-Safety (Injury) Hazards 3.3 Consider the list of hazards that follows, and rank each on a scale of 1 to 10 (10 being the worst). Also, classify each into the four OSHA categories according to your opinion. (a)Ground plug (third prong) is cut off on a power cord for an office computer. (b)Ground plug is cut off on a power cord for a shop wet-vac vacuum cleaner. (c)An electric drill with faulty wiring causes an employee to receive a severe shock, after which he refuses to use it. Another employee scoffs at the hazard, claims that he is “too tough for 110 volts,” and picks up the tool to continue the jobAfter consulting Table 3.1 & Figure 3.9, I understand that below are the Hazards classifications and OSHA categories. Sr. NoCase No.10-Point Scale Ranking(Table 3.1)OSHA Category(Figure 3.9)1a1De Minimus2b3Non-serious3c8Serious3.6 Name four basic approaches to hazard avoidance. There are no hard and fast rules to eliminate the workplace hazards but there are some concepts or approached to reduce the severeness of hazards with the passage of time when we used or applied at workplaces. Whish are: 1) The Enforcement Approach 2) The Psychosomatic Approach 3) The Engineering Approach 4) The Analytical Approach
P a g e | 3 3.9 What are the three lines of defense against health hazards? As we know that chronic exposure to noise is a health hazards and there are three main approaches to reduce or minimize the noise hazard at workplace, which are known as “Three lines of defense” against health hazards, which are as follows: 1-Engineering Control 2-Administrative or Work-Practices Control 3-Personal Protective Equipment (PPE) 3.13 What is the purpose of FMEA? Failure Modes and Effects Analysis (FMEA) basic purpose to identified and suggest recommendations to reduce or eliminate the failures. Safety incidents or failures have several origins and FMEA is used to trace effects of individual component failures on the overall or "catastrophic" failure of equipment. FMEA is an equipment oriented analytical tool instead of hazard oriented. 3.18 In the universal loss incident causation model, what is the difference between proximal factors and distal factors? To which category does management policy belong? During 1989, McMlay gave a new model which emphasized on the causes of “Loss Incidents” despite of incidents results or injury. According to him Proximal causes are the primary causes which are direct hazards of accidents in the conservative sense, for instance, missing guard on a bench press. On the other hand, Distal causes are the secondary causes which are indirect causes but as important as the major proximal causes since they are the contributary causes to the proximal causes. Management policy or attitude belongs to the distal cause. 3.33 What is a “Deadman control?” Describe an example not given in this book. A “Deadman control” is like a trigger switch or a managing mechanism that brings operating equipment into back safe mode, in the absence of a conscious action on the part of the operator. The typical control is a spring-loaded pushbutton switch as in a hand-held electric drill or hand-held saw. 3.44 Explain the distinction between guards and barriers in the application of engineering design principles. Safety guards are the permanent structure or part that keep workers safe or away from hazards which due to machines moving parts and provide a lasting solution to injury prevention. Whereas barriers or barricades are required to prevent people from entering an area where hazard or danger exists. Barriers are considered administrative control.
P a g e | 4 3.50 Identify 10 design principles or methods used to apply the engineering approach to reduce or eliminate hazards. The ten design principles or methods used to apply the engineering approach to eliminate or reduce hazards are as follows: 1-Eliminate 2-Substitute 3-Reduce or Slow down exposure. 4-Guards 5-Barriers 6-Warne Personnel or Caution 7-Warning Labels 8-Filters 9-Exhaust Ventilation system 10-Human Interface 3.20 Accident causes A, B, and C each has a probability of occurrence of about 1 in 1000, but the causes are mutually exclusive. Suppose that cause B does in fact occur in a given situation, what are the chances that cause A will occur in this situation? The probability of occurrence of Cause A is zero. If the causes are mutually exclusive, then the occurrence of Cause B rules out or excludes the occurrence of either Cause A or Cause C. 3.21 Using a pair of dice for a simulation device, suppose that an outcome of 11 represents an industrial accident. 1. (a) Draw a fault-tree diagram to illustrate the ways in which this accident could happen. 2. (b) Calculate the probability that this accident will happen in a given throw of the dice. 3. (c) Are the causes of this accident mutually exclusive? a)The fault tree-diagram to illustrate the ways in which this accident (outcome of 11 or roll of 11) could happen is as follows:
P a g e | 5 (b) Total number of possibilities = 2 Total number of events = 6*6 = 36 Probability = No. of possible outcomes / No. of total events = 2/36 = 0.0556 = 5.56% So probability of this even through a dice is 5.56%. (c) When throwing a dice, you cannot get both the outcomes simultaneously, i.e., it is impossible to obtain more than one combination outcome to obtain a sum of 11 on the two dices. So, both these events cannot happen together at the same time that’s why these events are mutually exclusive.3.24 A certain type of injury has tangible costs of $15,000 per occurrence and intangible costs estimated to be $250,000 per occurrence. Injury frequency is 0.01 per year, but would be reduced by half with the installation of a new engineering control system. What annual benefit would the new system provide? Tangible cost per occurrence = $15,000 Intangible cost per occurrence = $250,000 Total cost per occurrence = $15,000 + $250,000 = $ 265,000 Injury frequency per year before engineering control= 0.01 Injury frequency per year after engineering control= 0.005 Expected Cost/year = Cost per occurrence x Annual incidence frequency 1-Expected cost/year before EC Installation = $ 265,000 × 0.01 = $ 2,650 2-Expected cost/year after EC Installation = $ 265,000 × 0.005 = $ 1,325 Annual benefit = 2650 –1325 = $1325
P a g e | 6 3.25 A certain ventilation system would cost a firm approximately $60,000, which can be amortized over its useful life at a cost of $15,000 per year. Annual maintenance costs are expected to be $600 per year and monthly operating costs (utilities) $150 per month. The system is expected to facilitate production by reducing the amount of machine cleaning for an expected annual savings of $1200 per year. The primary benefit of the proposed ventilation system is expected to be the elimination of the need for respirators, which cost the company $4000 per year in equipment, maintenance, employee training, and respiratory system management. The ventilation system is expected to reduce short-term-illness complaints by an average of 6 per year and long-term illnesses by an average of 0.2 per year. Short-term illnesses result in a total cost of $600 per occurrence, including intangibles. Long-term illnesses are expected to result in a total cost of $30,000 per occurrence, including intangibles. Use a cost–benefit analysis to determine whether the ventilation system should be installed. What is the primary benefit of the ventilation system? Total Costs per year Amortization = $15,000 Maintenance = $ 600 Utilities = 150 × 12 = $1,800 Total Costs per year = $17,400 Total Benefits per Year Cleaning = $1,200 Resp equipment savings =$ 4,000 Short Term Illnesses = $3,600 Long Term Illnesses = $ 6,000 Total Benefits per year = $14,800 1-The decision based on Cost/Benefit analysis is to ventilation system should not be installed because its capital cost is higher than the benefits. 2-Primary benefit of the ventilation system installation is to prevent chronic health disease like long term illnesses which would be prevented and ultimately save a human health.
P a g e | 7 3.30 Event A has probability of occurrence 0.3, Event B has probability of occurrence 0.2, and A and B are independent. Either A or B is sufficient cause for loss incident Event C to occur. Calculate the probability of occurrence of loss incident Event C. The formula used to calculate the probability of occurrence of loss incident event C because of two independents events A & B, P[C] = P[A] + P[B] –P[A] P[B] Probability of occurrence of event A is P[A] = 0.3 Probability of occurrence of event B is P[B] = 0.2 Probability of occurrence of event C is P[C] P[C] = 0.3 + 0.2 –(0.3) (0.2) = 0.5 –0.06 = 0.44 The probability of occurrence of loss incident event C is 0.44 3.17 Alter the fault-tree diagram of Figure 3.2 to consider the possibility that the portable electric drill might be double insulated (i.e., sheathed in an approved plastic case to prevent electrical contact with the metal tool case).