From the Archives

FROM THE ARCHIVES A Plumb Job for IIHR

bY MaRGOT DICK

During the Great Depression, IIHR took on plumbing research that kept the doors open and the lights on. The work, such as important research to stop “back-siphoning,” saved lives and protected human health. Backsiphoning allowed contaminated water from toilets to inadvertently flow into sinks.

The 1930s were the height of the Great Depression. Unemployment was at an alltime high, and many hydraulic research institutes nationwide were closing for good. Facing these difficult times, IIHR turned to industry leaders. Though the country was in financial distress, safety and sanitation were still necessities.

In 1936, Francis Murray Dawson arrived at the University of Iowa and the Iowa Institute of Hydraulic Research (as IIHR was then known). At his previous job as head of hydraulics at the University of WisconsinMadison, Dawson had focused primarily on plumbing with his close friend and colleague A.A. Kalinske. Also a professor of hydraulics, Kalinske followed Dawson as he made his move across the Midwest. At Iowa, Dawson was not only able to continue his work on plumbing, but also to focus on the larger field of hydraulics as the new director of IIHR.

Together, Dawson and Kalinske conducted research on toilet backflow, water heater valves, water-hammer noises, vertical drains, and more. During World War II, they even conducted studies on grease traps to help make grease disposal in military kitchens more efficient. Their plumbing research put IIHR on the map in this field, and in 1938, IIHR was named the official testing agency of the National Plumbing Laboratory. The research — and the funding that came with it — helped keep the doors open at IIHR through difficult economic times.

SaVING LIVES

Dawson and Kalinske’s research on the safety of toilets and the movement of sewer water once it left the bowl was particularly significant and life-saving. In the 1930s, plumbers did not yet know that pipes need air circulation to prevent the creation of a vacuum. When water drains in a vertical pipe without holes to allow additional airflow, the water creates suction like someone drinking through a straw. This suction in the system can pull the water backward through the pipes and out other appliances in an action called “back-siphonage.”

In toilets, for example, contaminated water that should be drained out of the toilet bowl and into the sewage system could instead be pulled back into the home and flow out through the taps in the house, contaminating water used for drinking and bathing.

Dawson and Kalinske’s research helped ensure that toilets were designed and installed correctly to prevent sewage from contaminating clean water and reducing the chance of water-borne illness.

The 1930s were also a dangerous time to own a water heater. Explosions were frequent, generally killing those unfortunate enough to be in the building at the time. Dawson and Kalinske examined the cause of these explosions and found that they were not caused simply by high pressure, though that was a factor. Broken water heater casings were often the culprit. When water is heated above the boiling point in a high-pressure environment, a sudden pressure release turns the water to steam nearly instantaneously.

A sudden change from liquid to steam dramatically increases the volume of the liquid inside the water tank, which in turn increases the pressure in the closed system. When a water heater has a leak, the water will suddenly be exposed to a lower pressure outside the tank. Inside the tank, the steam has nowhere to go. This steam presses on all sides of the tank until it finally explodes, turning the heater into a rocket and damaging the surrounding area.

Dawson and Kalinske proposed that companies be required to add both pressure and temperature release valves to lower the risk of water heater failure. Though the explosion is not caused strictly by overpressurization of the system, a pressure release valve can still keep a heater from exploding. Dawson and Kalinske noted that when the excess steam flowed into pipes attached to the heater, the resulting pressure stabilization prevented an explosion. With this in mind, they suggested the implementation of pressure release valves in all new water heaters to discharge the surplus steam as soon as it was created.

Temperatures in a pressurized container like a water heater are also an issue; they can rise to more than 212 degrees before water turns to steam. To stop the change in state with sudden pressure drops, a release valve keeps the temperature from rising above the boiling point of water, removing the possibility of steam altogether.

The research conducted at IIHR during the Great Depression improved the health and safety of people everywhere and remains an important part of IIHR’s history.

TOP: Plumbing research, which began in the 1930s and continued even after World War II, earned IIHR the title of the official testing laboratory for the National Association of Master Plumbers.

bOTTOM: IIHR researchers explored the redesign of grease traps in drainage systems for the U.S. Army.