You may have thought about or discussed the question: Which invention has saved the most lives throughout human history?
The field of medicine has many claims on this. Vaccines, blood transfusions, and antibiotics are probably near the top. Within sanitation, there are some big arguments for antiseptics and toilets that drastically reduced the spread of disease. From agriculture, there is the advent of fertilisers and high-yield crops that enabled the world to feed itself.
But we’re engineers so let’s discuss some of the best life-saving inventions that come from the world of mechanical engineering.
Lifeboats refer to both small boats placed aboard ships that are used for emergency evacuation and rescue craft used to save crew and passengers from a vessel during an emergency.
Throughout history, large ships often had smaller boats on board, used for various applications, that could act as lifeboats in the event of a disaster. The sinking of the Titanic was the springboard for a movement to enforce regulations on the number of lifeboats a ship required. The Titanic had 20 lifeboats on board with a total capacity of 1178 people, this was on a ship capable of carrying 3330 passengers. In 1912, at the time of the sinking, this exceeded the regulation for the number of lifeboats required.
The first rescue purpose-built lifeboats were introduced in 1789 on the river Tyne in north-east England, prompted by tragedies at the mouth of the river. Eventually, England formed the Royal National Lifeboat Institution in 1824. They estimate they have saved over 140,000 lives since their founding.
Seat belts are one of many inventions that improved vehicle safety. During a car accident, the rapid deceleration of a vehicle causes the people inside to be thrown out of their seat leading to serious injuries. Seat belts prevent this by securing passengers.
The seat belt was invented in the late 1800s by English engineer George Cayley, originally to help keep pilots inside gliders. The first patent for seat belts was made in 1885 by the American Edward J. Claghorn, who wanted to improve safety for tourists inside his New York taxis. However, it wasn’t until the mid-1930s that physicians began urging manufacturers to provide lap belts.
The real breakthrough came with the invention of the 3-point seat belt in 1958 by Swedish engineer Nils Bohlin. This design, with the strap across the torso, helped secure both the upper and lower body improving passenger safety. By the 1970s most developed countries had a seat belt requirement in all cars. The first seat belt law requiring all passengers to wear one was brought into effect in Victoria, Australia in 1970.
Nils Bohlin passed away in 2002. Upon his death, studies by Volvo estimated his 3-point seat belt had saved more than a million lives in the 44 years since the invention. Studies show that in 2014 more than half (53–59%) of the people aged between 13-44 who died in car accidents were not wearing their seat belts.
Another significant car safety invention is the airbag. Although patents for rudimentary airbags date back to the 1950s, the first electromechanical automotive airbag system was invented in 1968 by the American, Allen Breed. The first vehicle sold to the general public with an airbag was the Oldsmobile Toronado in 1973. However, they weren’t fitted in most cars until the early 1990s and only became mandatory in new vehicles in 1998 (US).
Airbags are considered a supplemental restraint system as they are designed to help seat belts, not replace them. During an accident, an airbag rapidly inflates and then deflates as soon as the passenger’s head presses against it. This is extremely important, otherwise, the head would violently bounce back from the airbag.
Airbags must be deployed faster than a car can crash and therefore are released at speeds of over 200mph. When a car accident occurs, the rapid deceleration is detected by an accelerometer triggering the airbag circuit. This circuit passes a current through a heating element, igniting a chemical reaction that generates enough harmless gas to fill a nylon bag.
A study on 8 years of road accidents from 1985 to 1993 showed that airbags reduced fatalities by 23–24% in head-on collisions and by 16% in crashes of all kinds compared to vehicles fitted with only seat belts.
Hot weather can cause major health risks such as heatstroke that lead to a significant rise in deaths, with the elderly most at risk. Air conditioners have become an important way of preventing this. They were invented in 1902 by Willis Carrier, but it took another 60 years for residential air conditioners to become commonly used.
Air conditioners use chemical compounds called refrigerants to cool by repeatedly converting them from a liquid to a gas. This conversion requires energy that is supplied by warm air circulated through the conditioner. The refrigerant draws heat from the air before it is pumped back into the room.
To keep this process going the refrigerant must be converted back to liquid to be used again. This is done using a compressor to create high pressure, forcing it back into a liquid. This produces extra heat which is evacuated outside using condenser coils and fans.
Business Insider estimates that air conditioning has saved 2 million lives since its invention. Studies show that, since 1960, heat-related deaths in America have reduced by 80%. With temperatures increasing around the globe, air conditioning is bound to become a necessity in most homes.