Question 175: When we go for training in the desert, most ofthe soldiers perform Tayammum (dry ablution with clean earth) because of the cold weather, and sometimes due to the difficulty of making Istinjaa’ (cleansing the private parts with water after urination or defecation) as there is no place to screen yourself in such open areas. Since some scholars consider making Istinjaa’ one of the obligatory steps of Wudoo’ (ablution), could you please elaborate on this ruling?
Answer: Performing Istinjaa’ is not necessary for making Wudoo’; rather, it is obligatory after passing urine or stools. Moreover, it is not permissible to perform Tayammum in the presence of water, even if the weather is very cold unless one fears getting severely ill by using water. Also, it is not permissible to resort to Tayammum due to the lack of a covered place, as your colleague can cover you with a piece of cloth or the like when necessity demands it… read more here.