Water Pasteurization Indicator (WAPI)
Fred Barrett and Dale Andreatta
A wax-actuated thermometer that indicates when water has reached pasteurization temperature.
The Water Pasteurization Indicator (WAPI) is an open-source hand-made thermometer that indicates when water has reached pasteurization temperature and is safe to drink. Rather than waiting for water to boil (which occurs at 100 °C and is far beyond the required temperature for destroying microorganisms), a WAPI uses a melting wax to indicate that water has reached 65 °C. This saves fuel by eliminating the need to boil water to ensure that the pasteurization temperature has been reached.
Many organizations have made and distributed WAPIs including Agua Pura Para el Pueblo and Rotary International Clubs (such as Buford/North Gwinnett, Calabasas, and Monterey Sunrise).
WAPI’s can be purchased online for about 10 USD or built from local materials for much less, depending on local market prices.
Other temperature indicators such as candy thermometers.
Goal 6: Clean water and sanitation
Households (particularly those who typically boil their water)
