When the ceiling fan was not operating, the ACHUVC increased by 7 ACH above background when viruses were dispersed at 37°C (body temperature).
Understanding the characteristics of ceiling jet flow is important because most fire detectors and suppression devices are designed to operate within the ceiling jet; the increases in temperature and smoke concentration within the ceiling jet become trigger occupants to begin fire-fighting action or to evacuation.
Carried out at first by zeppelin airships, the bombing was later done by aircraft such as the Gotha bomber, which, by flying at night and often as high as 20,000 feet (forcing the crew to breathe bottled oxygen through a tube in the mouth), operated beyond the ceiling of many defensive fighters.
"The fire operated between the ceiling and the peaks of the roof," he said, adding that the fire started sometime after 9 a.m. and was under control by 1 30 p.m. Throughout the day, members of the congregation and neighborhood residents walked between police cars and stepped over fire hoses to hug each other and offer help.
The authors point out that the lack of transfer to functional domains was to be expected, as most participants in the study were not yet impaired in the cognitive domains that were targeted by the training interventions, with high proportions of participants operating at ceiling levels (Ball et al 2002).
In winter, operating a ceiling fan mixes warm and cool layers of air.
The plane's four General Electric turbofan engines can accelerate it past the speed of sound at its operating ceiling of 40,000 feet (12,000 m), but its normal cruising speed is subsonic.
Do not operate a ceiling fan if the bird is out of the cage as the bird could run into the spinning blades and die.
She controversially called Remploy factories "ghettoes" operating a "glass ceiling … with non-disabled people largely running the organisation and disabled people working in it".
Its operating ceiling was over 50,000 feet (15,000 m).
