Fire Behavior Intermediate SFFMA Objectives: 15-02.01 – 15-02.02 2Hrs received
SFFMA Objectives • 15-02.01 Trainee shall define the following units of measurements: • A. British Thermal Unit (BTU) • B. Fahrenheit (F) • C. Celsius (C) • D. Calorie (C) • E. Joule, the SI unit for energy • 15-02.02 Trainee shall define thermal balance and imbalance.
Units of Measurement for Heat • British Thermal Units (BTU) • The amount of heat required to raise the temperature of 1 pound of water 1 degree Fahrenheit • While not used in scientific and engineering texts, the Btu is still frequently used in the fire service
Units of Measurement for Heat • Fahrenheit • Of or relating to a temperature scale that registers the freezing point of water as 32° and the boiling point as 212° at one atmosphere of pressure • Celsius • Of or relating to a temperature scale that registers the freezing point of water as 0° and the boiling point as 100° under normal atmospheric pressure.
Units of Measurement for Heat • Calorie: • Any of several approximately equal units of heat, each measured as the quantity of heat required to raise the temperature of 1 gram of water by 1°C from a standard initial temperature, especially from 3.98°C, 14.5°C, or 19.5°C, at 1 atmosphere pressure. Also called gram calorie, small calorie. • The unit of heat equal to 1/100 the quantity of heat required to raise the temperature of 1 gram of water from 0 to 100°C at 1 atmosphere pressure
Units of Measurement for Heat • Joule – SI Unit for energy • The International System unit of electrical, mechanical, and thermal energy. • A unit of electrical energy equal to the work done when a current of one ampere is passed through a resistance of one ohm for one second. • A unit of energy equal to the work done when a force of one newton acts through a distance of one meter.
Thermal Balance • Thermal Balance: • The degree of thermal balance existing in a closed room during a fire's development is dependant upon fuel supply and air availability as well as other factors. The hot area over the fire (often termed the fire plume or thermal column) causes the circulation that feeds air to the fire. However, when the ceiling and upper parts of the wall linings become super-heated, circulation slows down until the entire room develops a kind of thermal balance with temperatures distributed uniformly horizontally throughout the compartment. In vertical terms the temperatures continuously increase from bottom to top with the greatest concentration of heat at the highest level.
Thermal Balance • What does thermal balance mean to the Fire Service and what can it teach us?