Anyone who establishes the Vedic fires normally maintains three fires: gārhapatya, āhavanīya and dakṣiṇāgni. Most of the special sacrifices are performed in the āhavanīya which is kindled by the fire brought from the gārhapatya.
The mound of āhavanīya is square and is situated on the eastern side of the sacrificial shed at a distance of twenty four padas or steps from the gārhapatya mound.
The fire is established at dawn when half of the sun’s disc has risen above the horizon. The adhvaryu lights a few fuel sticks on the gārhapatya fire and carries them in a vessel containing sand to the āhavanīya mound chanting the appropriate mantras. After establishing the fire it is propitiated with oblations of clarified butter and fuel sticks.
In case the fire goes out, prescribed prāyaścittas or expiations should be under-gone. Reverencing it before death is believed to confer celestial worlds on the sacrificer.
See also PAÑCĀGNI.