On any given day, in every corner of the world, people are actively working, going to school, driving or taking mass transit to work, relaxing at home or on vacation, or even working at home. Some people are even finding the time to sleep. Those who are working perform jobs that range from cleaning animal kennels to serving as the head of state of a country. Every job, in fact every activity a human performs, has a hazard associated with it. The common hazards we all are exposed to include:
- Slips, trips, and falls.
- Illness and disease.
- Foodâborne illness.
- Transportation: car accidents, pedestrian accidents, and bicycle accidents.
- Sports: organized sports (football, basketball, soccer) accidents and individual sports accidents (skiing, water sports, skate boarding).
- Electricalârelated accidents.
- Fires.
- Weatherârelated accidents.
- Identity theft.
- Internet intrusion.
On top of these more common hazards are specific/major hazards. For example, cleaning animal cages include:
- Being attacked by the animal.
- The bacteria, viruses, and parasites that might be in the animal waste.
- The design of the cage might pose problems: size, shape, material of construction, and sharp edges.
- The maintenance of the cage might pose problems: cleanliness, jagged metal or wood, and faulty locks/latches/gates/door.
- The condition of the floor.
- The electrical and/or HVAC system in the building.
- The building environmental conditions.
The major hazards associated with being a head of state include:
- Stress from decision making.
- Stress from the potential for war.
- Stress from political rivals.
- Potential for assassination.
- Potential for transportation accidents: airplane crashes (i.e. the President of Poland died in an airplane crash in Russia in 2010 (1).).
Hazardous occupations, for instance, firefighting, have numerous hazards associated with dayâtoâday activities. Risk assessment tools and techniques can be used to analyze individual jobs for risks. It is obvious that every activity the president does is analyzed for hazards. Jobs or tasks like firefighter, chemical plant worker, electrician, and even office workers are usually analyzed using tools such as job hazard analysis (2).
The focus of this book is analyzing complex systems, tasks, and combinations of tasks for hazards and the associated risks. Most of the major accidents that occur each year result from a series of events that come together in an accident chain or sequence and result in numerous deaths, environmental consequences, and property destruction. These accidents can occur anytime in the system's life cycle. One of the events from history that demonstrates this is the sinking of the Swedish ship Wasa (pronounced Vasa) on 10 August 1628 (3). The ship was fabricated between 1626 and 1628. In those days engineering of the ships was performed by the shipwright and he used his experience to determine factors such as the center of mass and the amount of ballast the ship should have. Because of various events, pressure was put on the shipbuilders to complete the ship ahead of the planned delivery time. The ship was completed and ready for sail on 10 August 1628. The ship was very ornately decorated and was heavily laden with armament. As the ship left port on its maiden voyage on that calm morning, a gust of wind hit the ship, filling her sails. The ship heeled to port and the sailors cut the sheets. The ship righted itself, but then another gust of wind hit the ship and it tipped to port far enough that water entered the gun ports. This was the event that led to the loss of the ship and approximately 30â50 lives. However, the loss of the ship was probably due to one of two design flaws: first the ship was probably too narrow for its height and, second, the ship did not carry enough ballast for the weight of its guns on the upper decks. A contributing factor was the height above sea level of the gun ports that allowed water to enter the ports when the ship listed to port. Since, as stated above, engineering of ships was more seat of the pants than a systematic design process, the real reason(s) for the disaster could only be speculated. The ship was raised from her watery grave in 1959 and has since been moved to a beautiful museum facility in Stockholm. The ship itself can be studied, but other factors such as whether the guns were properly secured, how many provisions were on the ship, and so forth will remain a mystery. Accidents can occur in any phase of a system's life cycle. For the Wasa accident, it occurred in the ship's initial phases.
A much more recent accident occurred on 23 February 2018, in Dallas, Texas, in which Atmos Energy, the country's largest natural gas distributor, caused an explosion and fire via a natural gas leak, killing one 12âyearâold girl and injuring others (4). Atmos Energy also operates in Colorado, Kansas, Kentucky, Tennessee, Virginia, Louisiana, and Mississippi. The incident involved piping that leaked due to pressure on the piping. The accident investigators found that heavy rain caused underground pressure that pushed rock formations upward, which in turn caused pressure on the system, which caused the leakage. Aging pipes have since been replaced with a more flexible, highâgrade plastic. Weather and aging pipes were the primary drivers in the event.
Risk assessment tools and techniques, if applied systematically and appropriately, can point out these types of vulnerabilities in a system. The key term here is âsystematic.â A risk assessment must be systematic in nature to be most effective and should begin early in the life cycle of complex systems. Preliminary hazard analysis (PHA) is an example of a tool that can be applied at the earliest phase of system development. As the design of a system progresses, other tools can be applied, such as failure mode and effects analysis (FMEA) and fault tree analysis (FTA). Probabilistic risk assessment (PRA) and human reliability analysis (HRA) are techniques used to analyze very complex systems. These tools usually require a wellâdeveloped design, an operating philosophy, and at least working copies of procedures to provide enough mate...
