Save as otherwise expressly provided in this Act, no building or land shall be entered without the consent of the occupier, or if there is no occupier of the owner thereof, and no such entry shall be made without giving the said occupier or owner, as the case may be, not less than four hours, written notice of the intention to make such entry:
     Provided that no such notice shall be necessary if the place to be inspected is a factory or workshop or trade premises or a place used for carrying on any trade, calling or occupation specified in section 277 or a stable for horses or a shed for cattle or a latrine, privy or urinal or a work under construction, or for the purpose of ascertaining whether any animal intended for human food is slaughtered in that place in contravention of this Act or any bye-law made thereunder.