The British thermal unit (BTU or Btu) is a traditional unit of energy equal to about 1055 joules. It is the amount of energy needed to cool or heat one pound of water by one degree Fahrenheit. In scientific contexts the BTU has largely been replaced by the SI unit of energy, the joule.
The unit is most often used as a measure of power (as BTU/h) in the power, steam generation, heating, and air conditioning industries, and also as a measure of agricultural energy production (BTU/kg).]verification needed[ It is still used in metric English-speaking countries (such as Canada), and remains the standard unit of classification for air conditioning units manufactured and sold in many non-English-speaking metric countries.]verification needed[ In North America, BTU describes the heat value (energy content) of fuels.
A tubular grate heater is any grate or heat exchanger for a fireplace designed from metal tubing. Through the tubing is circulated home air that becomes heated by the fire. The air is then vented back into the room and home. It is a heat recovery device that improves the efficiency and ability of a fireplace to get the heat from the fire out and into the home. From simple to ornate, they can contribute significantly to the overall comfort of a room and potentially to a whole house. This in turn will reduce the amount of firewood needed to achieve the same comfort level, potentially reducing heating costs and expenses. Heaters increase the efficiency of a fireplace and hence the amount of heat that makes it from the fireplace out into the home. They work by having naturally convected and forced air funneled into the metal heat exchanger tubing that is then heated by the coals and/or fire. They draw in cold air from the floor and blow heated air back out into your home. This adds an element of conductive and convective heating to the radiant heat typical of a basic fireplace. Grate heaters have been called many things: heatilator, hearth heater, fireplace blower, fireplace grate heater, Fireplace Furnace, tubular grate heater, etc.
The ideal tubular grate heater would be built like an ideal heat exchanger with as large a surface area as possible with material suitable to minimize the heaters thermal deterioration yet provide good thermal conductivity with a high airflow rate, similar to your home furnace. However the unique environment of a fireplace and the burning of gas, wood, coal, pellets, etc., require specific heater designs and material construction making few, if any, grate heaters compatible with all fuels.
A disaster is a natural or man-made (or technological) hazard resulting in an event of substantial extent causing significant physical damage or destruction, loss of life, or drastic change to the environment. A disaster can be ostensively defined as any tragic event stemming from events such as earthquakes, floods, catastrophic accidents, fires, or explosions. It is a phenomenon that can cause damage to life and property and destroy the economic, social and cultural life of people.
In contemporary academia, disasters are seen as the consequence of inappropriately managed risk. These risks are the product of a combination of both hazard/s and vulnerability. Hazards that strike in areas with low vulnerability will never become disasters, as is the case in uninhabited regions.