Section 81

Nothing is an offence merely by reason of its being done with the knowledge that it is likely to cause harm, if it is done without any criminal intention to cause harm, and in good faith for the purpose of preventing or avoiding other harm to person or property.

Explanation -

It is a question of fact in such a case whether the harm to be prevented or avoided was of such a nature, and so imminent, as to justify or excuse the risk of doing the act with the knowledge it was likely to cause harm.

Illustrations

A, the captain of a steam vessel, suddenly and without any fault or negligence on his part, finds himself in such a position that, before he can stop his vessels, he must inevitably run down a boat B with twenty or thirty passengers on board, unless he changes the course of his vessels, and that, by changing his course, he must incur risk of running down a boat C with only two passengers on board, which he may possibly clear. Here, if A alters his course without any intention to run down the boat C and in good faith for the purpose of avoiding

A, in a great fire, pulls down houses in order to prevent the conflagration from spreading. He does this with the intention in good faith of saving human life or property.