HFS303: Discuss the differences between the reliability and resiliency of a system A lighting system set up is shown in Figure : Safety, Risk and Resilience Engineering TMA Assignment SUSS, Singapore

Question 1

(a) Discuss the differences between the reliability and resiliency of a system.

(b) A lighting system set up is shown in Figure Q1(b) which consist of 7 components and a bulb. If each of the component has a reliability (probability of success) of 0.8, what is the overall reliability of the system?

(c) Based on the Reliability Block Diagram in Figure Q1(b), develop an equivalent Fault Tree for the system. (Note: Fault Tree’s top event is the failure of bulb to light up.)

(d) Propose a method to improve the reliability of a system.

(e) Illustrate and discuss Erik Hollnagel’s FOUR (4) basic elements of a resilient
system using the example of the Singapore Traffic Police managing drivers
speeding on road.

Question 2

(a) Using the concept of “Adequately Safe System”, discuss if the following are
considered adequately safe.

(i) A group of 60 workers working with metal stamping machines are
exposed to 92 decibels dB(A) for 8 hours a day. They have been provided
with ear muffs which can attenuate the noise level up to 20 decibels
dB(A).

(ii) A company is formulating a new chemical product that is likely to be
highly flammable. This is a new product with no known safety standards
available. The company has instructed that product testing can only be
carried out by a trained chemist in a room with a signage that prohibits
smoking

(b) A manufacturing company has recently bought a new robotic machine to help in the production process. Despite the investment, the company’s management noted that the overall productivity of the company has decreased. Further investigation revealed that due to the implementation of automation, the workers’ tasks were redesigned to carry out monotonous step-by-step operations.

(i) Describe with the help of a diagram, the concept of Sociotechnical
approach in the implementation of the new robotic system.

(ii) Based on the principles of Sociotechnical System, explain and
recommend to the company ways to improve both the social and technical
aspect of the system.

Question 3

A person employed as a cleaner in a condominium was asked by the security supervisor to change a faulty light bulb at 9 pm when a resident made a complaint about flickering light. The technician had gone home and all the equipment including the ladder was kept locked in the store. The cleaner used a chair to change the light bulb and in doing so, he fell and injured his back. You have been appointed to investigate into the accident.

(a) Explain root cause and the importance of accurate identification of root causes in accident investigation.

(b) Demonstrate the use of 5 WHYS to analyse and identity the root cause of the accident. The 5 WHYS should contain at least THREE (3) different branches of analysis.

(c) Demonstrate the use of 6M and the Ishikawa Diagram (Fishbone Diagram) to analyse and identify the root cause of the accident.

(d) Demonstrate the use of the Swiss Cheese Model to analyse and identify the root cause of the accident.

Question 4

(a) Explain Performance Shaping Factors.

(b) Examine the EIGHT (8) key Performance Shaping Factors and illustrate with
examples, how they can impact the performance of a firefighter.