Ordained priests tend a fire temple's flame on a fixed schedule of five daily periods, the gahs, feeding it with wood, reciting the appropriate prayers at each attendance, and covering it between feedings, a routine of continuous, disciplined care rather than a fire simply left to burn unattended. Zoroastrian teaching holds that fire is not itself worshipped as a deity but functions as a visible symbol of Ahura Mazda's light, purity and truth, so the priest's care of the flame is understood as an act of devotion directed through the fire rather than toward it, a distinction Zoroastrians themselves have long emphasized against a common outside misreading of the practice as fire worship.
Access to a fire temple's inner sanctum is restricted to Zoroastrians in good standing, and in some communities specifically to ordained priests, a boundary maintained partly out of purity concerns surrounding the fire and partly reflecting broader historical patterns of religious endogamy within the community. Practice differs somewhat between the two major branches of the tradition: Parsi communities in India, descended from Zoroastrians who emigrated from Iran roughly a millennium ago, and Zoroastrians who remained in Iran under subsequent Muslim rule have each developed their own institutional and liturgical particulars, though both maintain the same essential structure of graded consecrated fires tended through a fixed daily cycle of priestly attendance. The Atash Bahram at Yazd in Iran and several major fires in India are reported by their communities to have burned, with continuous tending, for many centuries.