By Bill Ivey

Principal Consultant

Human skin can be easily scalded if it’s exposed to very hot water or steam. Depending on the temperature of the water and length of time exposed, damage to the skin can range from superficial to severe. The most severe damage is a third-degree burn which penetrates all skin layers and is often life threatening.

How Quickly Can Hot Water Burn You?

How long does it take for hot water to cause a third-degree burn? Anywhere from half a second to five minutes, depending on the temperature of the water or steam and amount of time exposed:

Time               Temperature (Fahrenheit)

5 minutes         120 degrees

30 seconds      130 degrees

5 seconds        140 degrees

1.5 seconds     150 degrees

.5 second         160 degrees

Residential water heaters are capable of heating water to 140 degrees and higher. Water heating equipment for commercial buildings can heat water to 180 degrees. All water heaters used to heat domestic water for bathing and washing are required to have controls which are user adjustable.

Safety Standards and Recommended Temperatures

Building codes and federal regulations, such as the American with Disabilities Act, limit a temperature of 120 degrees for water supplied to plumbing fixtures, such bathtubs, showers and sinks. Although 120 degrees is now considered the maximum allowed supply temperature, 110 or even 105 degrees is plenty hot for these fixtures and is safer and more energy efficient.

Some common causes of serious scalding injuries are water heater temperature settings that are too high, water heater controls that are defective, design or installation defects, defective operation and maintenance, construction safety lapse, industrial plant safety lapse and inadequate safety measures for disabled persons or persons suffering from illness.

Steps to Prevent Scalding Injuries

Follow these measures to mitigate exposure to scalding burns:

• Practice adequate water heater maintenance.
• Don’t trust the dial setting on a domestic water heater as they are not accurate. Instead, set the water heater at 120 degrees or less by testing the water at several faucets with a thermometer
• Test water temperature at bathtubs and showers regularly with a thermometer. Tub/shower valves can be adjusted internally to limit the hot-water to cold-water mix ratio.
• For residential buildings with disabled persons or persons suffering from illness, the tub/shower valves should be limited to 105 degrees.
• Wear or use personal protective equipment when working around hot water or steam systems.