Fire Doors and standard door frames

I would suggest double checking your order and ensure you didn't make a mistake and order the fire doors. If the mistake is with the supplier and they have charged you for moulded doors, you've had a result. All that aside, doors come in a few different widths/depths/thickness's. Fire doors tend to be the thickest but that doesn't mean it won't fit. I would measure the width & thickness of your new fire door, and compare it to width of your lining and the measurement from the front of your door lining to the doorstop. Ensure you measure the correct side where door will be hung i.e measure from doorstop, across keep and to the front of lining. If they are the same, then theres no problem hanging the doors. If the depth is different then its the small job of taking off doorstop, moving it over then making good disturbed area. If the fire door is too wide for the door lining then its a bit more difficult and the solution varies on a number of factors. hope i helped.