Any materials which could give off fumes should not penetrate occupied parts of the building. Such material may only be used where there is a continuous barrier which will prevent fumes from entering any occupied areas.
Part D stipulates the conditions where such materials can be used and the minimum standards which need to be applied.
Approved Document D – Requirement
D1: If insulating material is inserted into a cavity in a cavity wall reasonable precautions shall be taken to prevent the subsequent permeation of any toxic fumes from the material into any part of the building occupied by people.