The spring does all the work closing the door. When you open a door, you are stretching out this spring. The spring wants to ''snap'' the door closed, but hydraulic fluid must flow through valves as the door closes. It is the hydraulic fluid that allows the door to close smoothly and slowly.
Door Closer Types
Overhead Concealed Mounts in the frame header
Surface Bolts to the surface of the door or frame
Floor Concealed in the floor
ADA Requirements
ADA has rules for door hardware including closers. It states that interior doors must be opened with 5 lbs. of force, or less, to meet code. For exterior doors, it is 8.5 lbs. of force.
Closers meeting ADA requirements are said to be ''Barrier-free''.
It all comes down to spring strength (size). Barrier-free closers usually have lighter springs, making it easier to open a door. Look for a closer adjustable sizes 1 - 4, or even better 1 - 6. These give you the most flexibility to adjust the closer to make it easy to open.
Rim Device is used on single doors or pairs of doors that
usually have a frame in the middle. The strike is then mounted
on the frame.
Surface Vertical Rod is used on pairs of doors. The top and bottom
rods go into the frame on top of the door and in the threshold or
floor.
Concealed Vertical Rods are similar to the Surface Vertical Rods;
however, the top and bottom rods are concealed within the door rather
than being located on the surface of the door.
Mortise Device has the locking mechanism inside of the door. These are
for high use or high security doors.
Flush bolts or surface bolts are used with a standard lock to hold an inactive door in
place. They are mounted on the edge of the door and are not visible when the door
is closed.
Flush Bolts Types
Standard lever extension flush bolts are the most common type. One lever is placed on the top of the door and the other is placed on the bottom. You manually push the levers up or down when the active door is open.
Automatic flush bolts operate just like the standard lever extension flush
bolts except that the lever opens automatically. When the active door is
opened the flush bolts automatically retract.
Combination flush bolt has an automatic flush bolt at the bottom and a standard
flush bolt at the top. The top flush bolt can be opened by pushing a button on the
bolt face.
The spring does all the work closing the door. When you open a door, you are stretching out this spring. The spring wants to ''snap'' the door closed, but hydraulic fluid must flow through valves as the door closes. It is the hydraulic fluid that allows the door to close smoothly and slowly.
