damp

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damp,

in mining, any mixture of gases in an underground mine, especially oxygen-deficient or noxious gases. The term damp probably is derived from the German dampf, meaning fog or vapor. Several distinct types of damp are recognized. Firedamp is methanemethane
, CH4, colorless, odorless, gaseous saturated hydrocarbon; the simplest alkane. It is less dense than air, melts at −184°C;, and boils at −161.4°C;. It is combustible and can form explosive mixtures with air.
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 and other flammable gases, often mixed with air; it results from the decomposition of coal or other carbonaceous materials. Explosive mixtures of firedamp with air usually contain from 1% to 14% methane. The mixture of gases that remains after a firedamp explosion is called afterdamp; it consists chiefly of carbon dioxide and nitrogen. Chokedamp is any mixture of oxygen-deficient mine gases that causes suffocation. (In England, carbon dioxide is called chokedamp.) Several methods are used for detection of damps. The Davy safety lampsafety lamp,
oil lamp designed for safe use in mines and other places where flammable gases such as firedamp (see damp) may be present. Its invention (c.1816) is usually attributed to Sir Humphry Davy.
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 is one of the earliest detection devices. The color and height of the lamp flame indicate the amount of firedamp present; if the flame is extinguished, chokedamp is present. Canaries were formerly kept in mines; the birds are overcome by relatively small quantities of noxious gases, and their death warned the miners of the presence of damps. Special colorimetric detectors are now used. The methanometer is a special portable instrument used to detect firedamp.

damp

[damp]
(engineering)
To reduce the fire in a boiler or a furnace by putting a layer of damp coals or ashes on the fire bed.
(mining engineering)
A poisonous gas in a coal mine.
(physics)
To gradually diminish the amplitude of a vibration or oscillation.
References in periodicals archive ?
In response to the "ASHRAE Position Document on Limiting Indoor Mold and Dampness in Buildings," the ASHRAE Board of Directors authorized a task group to seek a clear definition of, and objective criteria for, a damp building.
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A At which time of year did you discover the dampness in the two closets?
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It also discusses conditions that determine the presence of mold, and measures for controlling its growth indoors--primarily by preventing or minimizing persistent dampness on interior surfaces and in building structures.
In some cases, buyers could arrange surveys to assess potential problems - for example stemming from dampness and possible dry rot - at little or no cost.
The floors are ideal for food packaging and processing areas because they tolerate dampness as a result of spills and they resist thermal shock as a result of high temperature washdowns.
DREAM BABY'S DE-HUMIDIFYING DRY EGG: Tee-Zed Products LLC has introduced Dream Baby's De-Humidifying Dry Egg to help remove excess moisture and dampness from the air.
Epidemiological studies have demonstrated associations between building dampness or mold and upper respiratory symptoms, (2,3) cough, (4,5) wheeze, (4,6) shortness of breath, (7,8) asthma symptoms in people with asthma, (3,6) development of asthma, (9,10) fatigue, (2,11) headache, (11) eye irritation, (11) and skin irritation.
A dampness and mold score was created with information from almost 7,000 adults ages 18 and older as well as the inspectors who had visited their homes.
The paper concludes that issues associated with mold, dampness and indoor air quality continue to provide challenges for lenders, servicers and others involved with real estate loans.