Water heating by a domestic water heater. Two conflicting safety issues affect water heater temperature—the risk of scalding from excessively hot water greater than , and the risk of incubating bacteria colonies, particularly "Legionella", in water that is not hot enough to kill them. Both risks are potentially life-threatening and are balanced by setting the water heater's thermostat to . The European Guidelines for Control and Prevention of Travel Associated Legionnaires’ Disease recommend that hot water should be stored at and distributed so that a temperature of at least and preferably is achieved within one minute at points of use. If there
Spread Component scale; it has no upper limit. Spread Component Spread Component (SC) (as used in the National Fire Danger Rating System) is a rating of the forward rate of spread of a headfire. Deeming states that "the spread component is numerically equal to the theoretical ideal rate of spread expressed in feet-per-minute." This carefully worded statement indicates both guidelines (theoretical) and cautions (ideal) that must be used when applying the spread component. Wind speed, slope, and fine fuel moisture are key inputs in the calculations of the spread component, thus accounting for a high variability from day to day. The spread