Upon affixing a mezuzah to the doorpost:

Upon building a protective railing around one's roof:

Upon immersing in a mikveh metal or glass utensils (used for the preparation or serving of food or drink) that have been made by or purchased from a gentile:

An olive-size piece of dough must be separated and burned from each batch of dough that is at least 2 pounds 10 ounces. Regarding the amount of dough required for the recitation of the blessing, opinions vary from 3 lbs. 10.7 oz. - 4 lbs.15.2 oz. Upon separating: