To replace fireplace glass, remove the old glass, and place a new fireplace glass in the position previously occupied by the old glass. Start by gathering necessary tools and material including a screwdriver, work gloves, pliers and a replacement glass.
To remove the old glass, first protect your hands with the work gloves, and locate the brackets that hold the glass onto the frame. The brackets are typically located at the door's bottom. Once you locate them, use a screwdriver to loosen and remove the screws that mount the brackets, and use pliers to loosen the screws that attach the lintel clamps to the glass panes. To prevent the glass from falling, prop it with your hand as you loosen the screws. Once the screws are off, release the panes from the clamp, tilting the glass as needed. Detach the glass from the frame, and set it aside.
Once the old glass is off, place the new panes in place, and secure them with the lintel clamps, tilting them as needed for proper positioning. Using your hand, support the new glass at the bottom, and use pliers to mount the clamps in place with screws. Place the brackets back into position, and attach the new glass onto the frame with screws. Finally, examine the installation of the new glass, and fix any defects as needed.