Document Q is the latest addition to Building Regulations. It means that there are now recognized security standards for doors and windows in all new homes. The new standards require all doors and windows to be made to a design that has been shown, by test, to meet the security requirements of PAS24:2012.
The first thing to make clear is Document Q mainly applies to new dwellings, so replacement doors and those being Installed into a domestic extension are not required to have the upgraded security standards.
There is a good argument to say that all BiFolds should include the upgrades to ensure they meet Document Q. But until there is a level playing field where all BiFolds are required to meet the standard then it is important that when requesting quotes for BiFolds that you clarify if Document Q is required.