Can I lock fire doors in office building?

[Guest Ian Will]

We occupy three floors of a self contained office building with fire doors on each floor( besides the external door for entering ). We are going to let the ground floor. When we have the tenant I wondered if I can make the fire doors on the top two floors lockable. To be locked at the end of the day. Is this permisible.

[Safelincs]

You should be able to lock, as long as you have a foolproof routine to ensure that your entire office is emptied beforehand. If this cannot be achieved you could install push pads on the door of your office to allow escape in an emergency while keeping the door shut from outside.

Harry