Section
The requisites for tayammum are five: (1) the presence of a valid excuse such as travel or illness; (2) the entry of the prayer time; (3) searching for water and being unable to use it; (4) failing to find any water after that search; and (5) clean earth that raises dust—if it is mixed with lime or coarse sand, tayammum is invalid.

Its obligatory elements are four: intention; wiping the face; wiping the hands, including the elbows; and observing the prescribed order. Its recommended elements are three: pronouncing the basmalah, giving precedence to the right over the left, and maintaining continuity.

Tayammum is nullified by three things: anything that breaks wuduʾ, seeing water at a time other than during the prayer itself, and apostasy.

A person with splints or casts wipes over them, performs tayammum, and prays; he need not repeat his prayer provided the splints were applied while he was in a state of purity. One must perform a fresh tayammum for every obligatory prayer, though any number of supererogatory prayers may be offered with a single tayammum.

Section
Every liquid that exits either of the two passages is impure, except for semen. Washing away all forms of urine and excrement is obligatory, except for the urine of a baby boy who has not yet eaten solid food—this is purified by merely sprinkling water over it. No impurity is overlooked save a small amount of blood or pus.

A creature that has no flowing blood, if it falls into a vessel and dies there, does not render the vessel impure. All animals are pure except the dog, the pig, and anything born of either or both of them. Every carcass is impure except fish, locusts, and human beings.

A vessel licked by a dog or pig must be washed seven times, one of which is with earth. As for other impurities, one thorough washing suffices, though three is preferable. If wine turns into vinegar on its own, it becomes pure; should it be made to ferment into vinegar by adding any substance, it remains impure.