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ARE 5.0: PPD > Mechanical Systems > Flashcards

Flashcards in Mechanical Systems Deck (6)
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The energy produced per unit of surface area per hour by a seated person at rest

1 met (metabolic unit) = 18.4 Btu/hr-ft^2


Factors: air temperature, humidity, air movement, surface temperature, clothing, ventilation

Factors in thermal comfort


Relative humidity

Percent moisture in the air : maximum amount of moisture the air can hold at a given temperature without condensing



measure of an object's ability to absorb and radiate heat (emittance: ratio of the radiation emitted by an object at a given temperature to the radiation emitted by a black body at the same temperature)


mean radiant temperature (MRT)

a weighted average of all surface temperatures in a room and the angle of exposure of the occupant to these and any sunlight present


operative temperature

average of air temperature of a space and the MRT of the space ;; can be measured using a black globe thermometer