Davey

Hi I just wanted to ask for some advise please. My work building is located on two floors, but we recently moved downstairs while an air conditioning system is fitted upstairs. I am concerned because now that we are on the ground floor the only accessible fire exit is in the reception area and right next to the front door. This means that if there was a fire in reception there is no way out of the building. There is another fire exit downstairs but this blocked because of building work. All of the windows downstairs are also locked and require a key to open them. I've raised this with HR on four occasions and they have just ignored me. So i raised it again and today I was confronted as a trouble maker and was told the one next to the front door is all they need and to drop it. This doesn't seem right can anyone please advise me?