Related Rule
Germany
Practice Relating to Rule 22. The Principle of Precautions against the Effects of Attacks
Germany’s Military Manual (1992) states: “Civil defence tasks are particularly warning … construction of shelters, and other measures to restore and maintain order.” 
Germany, Humanitarian Law in Armed Conflicts – Manual, DSK VV207320067, edited by The Federal Ministry of Defence of the Federal Republic of Germany, VR II 3, August 1992, English translation of ZDv 15/2, Humanitäres Völkerrecht in bewaffneten Konflikten – Handbuch, August 1992, § 520.
The Report on the Practice of Germany states that the precautions required against the effects of attacks have to be taken mainly by the civil defence. It quotes a representative of the Ministry of Internal Affairs, who said at an ICRC expert meeting in Geneva that Germany had an integrated system of assistance to cover both peacetime disaster control and civil defence in case of armed conflict. 
Report on the Practice of Germany, 1997, Chapter 1.7.
Upon ratification of the 1977 Additional Protocol I, Germany stated that it understood the word “feasible” to mean “that which is practicable or practically possible, taking into account all circumstances ruling at the time, including humanitarian and military considerations”. 
Germany, Declarations made upon ratification of the 1977 Additional Protocol I, 14 February 1991, § 2.