The Hartford Steam Boiler Inspection and Insurance Company was founded on June 30, 1866. The company was conceived at a time when catastrophic boiler explosions were common events, one occurring about every four days.
Up until the 1850s in the United States, a great deal of manufacturing was carried on by small plants located in rural areas. Water from streams and rivers was the source of power for equipment. However, water power had reached the limits of its industrial capacity. Manufacturers turned to steam boilers and engines. The industrial revolution was underway.
The advent of steam power created a new industrial hazard – disastrous boiler explosions. These tragedies occurred with increasing frequency with loss of life and property. Though the potential of steam power seemed infinite, controlling the power and safely harnessing it was crudely developed. As applications for steam power became more complex, the dangers became more acute.
In 1919, the Hartford Steam Boiler Insurance and Inspection Company got tired of paying the claims on all those broken boilers, so they came up with the idea of this special piping configuration and mandated it for anyone who wanted insurance on their steam boiler. Before long, everyone was calling it the Hartford (or Underwriters) Loop.