The results showed that the temperature rise of smoke layer was very low, but the descending of smoke layer was quick.

试验结果表明，烟气在大空间内的温度并不高，但烟气层下降速度很快。

youdao

The smoke layer can been in definite height and not descend when the smoke exhaust rate is larger than that of generating smoke.

当中庭排烟速率大于或等于产烟速率时，烟气层就能够保持在一定高度上不降下来。

youdao

This involves keeping the height of the smoke layer above the highest level of occupancy for a defined period of time, longer than the expected time to evacuate the building.

这就要求在规定的逃生时间内，保证烟气层存在于规定的逃生安全高度以上。

youdao

It is bright and exotically fruited with a foundation layer of campfire smoke.

FORBES: The EYE: Land Rover Defender, Spring Colognes And Polos

"An inversion layer is keeping the smoke close to the ground, limiting visibility and reducing helicopter air operations, " Berry said.

CNN: Firefighters make headway in California wildfire