Search results
Results From The WOW.Com Content Network
A 5% displayed LFL reading for methane, for example, would be equivalent to 5% multiplied by 4.4%, or approximately 0.22% methane by volume at 20 degrees C. Control of the explosion hazard is usually achieved by sufficient natural or mechanical ventilation, to limit the concentration of flammable gases or vapors to a maximum level of 25% of ...
Any mixture of methane and air will therefore lie on the straight line between pure methane and pure air – this is shown as the blue air-line. The upper and lower flammability limits of methane in air are located on this line, as shown (labelled UEL and LEL, respectively). The stoichiometric combustion of methane is: CH 4 + 2O 2 → CO 2 + 2H ...
The lower flammability limit or lower explosive limit (LFL/LEL) represents the lowest air to fuel vapor concentration required for combustion to take place when ignited by an external source, for any particular chemical. [29] Any concentration lower than this could not produce a flame or result in combustion.
The Life Safety Code (NFPA 101) [5] and Section 803.1 of the International Building Code limit finishes for interior walls and ceilings to materials in three classes (A, B, or C, with A being the lowest flame spread and C being the highest) and gives greater restrictions for certain rooms:
The lower flammability limit (LFL), [1] usually expressed in volume per cent, is the lower end of the concentration range over which a flammable mixture of gas or vapour in air can be ignited at a given temperature and pressure. The flammability range is delineated by the upper and lower flammability limits. Outside this range of air/vapor ...
Flammable gases – Gases which at 20 °C and a standard pressure of 101.3 kPa: are ignitable when in a mixture of 13 percent or less by volume with air; or; have a flammable range with air of at least 12 percentage points regardless of the lower flammable limit. Alternative sign. Division 2.1 Non-flammable non-toxic gases – Gases which:
Concrete is a composite material composed of aggregate bonded together with a fluid cement that cures to a solid over time. Concrete is the second-most-used substance in the world after water, [1] and is the most widely used building material. [2] Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminium combined. [3]
Concrete has a very low coefficient of thermal expansion, and as it matures concrete shrinks. All concrete structures will crack to some extent, due to shrinkage and tension. Concrete which is subjected to long-duration forces is prone to creep. The density of concrete varies, but is around 2,400 kilograms per cubic metre (150 lb/cu ft). [1]