הלכה אויף יהושע 5:14

When performing the rite of "falling on the face", after the service, some fall on the face, some prostrate themselves. The latter is forbidden on a stone floor, except in the Temple of Jerusalem, as has been explained in the laws concerning Idolatry. [Even] a worthy person may not fall on his face unless he is conscious that he is a righteous man like Joshua.^*(Joshua 5:14) “And Joshua fell on his face to the earth, and did worship.” He should only incline his face somewhat, but not press it against the floor. It is permissible to recite the service of prayer in one spot and "fall upon the face" elsewhere.