The most important thing about door closers has nothing to do with the closers themselves. Before installing, servicing or adjusting a door closer, make certain the hinges are properly lubricated, the hinge screws are tight and the door closes smoothly and latches properly. If the door is not operating properly, no door closer will be able to solve the problems.
The purpose of a door closer is to close and latch the door under controlled operation every time, preventing slamming and minimizing the sounds that occur as the door is closing. For the purpose of this article, we will only discuss swinging door closers including overhead concealed, surface mounted and floor closers.
Door closing equipment has been around for well over 100 years. Some of the original products are still sold today, such as spring hinges, springs, weights, door checks and door closers. An early Norton closer has the name “Door Check” manufactured into the arms.
Door closers come in different applications, configurations, sizes and shapes. They can be mounted into the floor beneath the door, into the header area above the door, and surface mounted onto the face of the door. Each type of door closer has its advantages and disadvantages.
Most architects install concealed door closers on the public exterior doors of a building because of the aesthetics.
Early pot (traditional) closers would wind up the clock-style spring as the door is being opened. The spring would unwind as the door is closing. To control the closing speed, the spring would drive a piston, forcing fluid through orifices in the cylinder. Many pot closers have two holes in different positions. The first, larger hole would permit faster movement (sweep speed). The second, smaller hole closer to the end of the travel, created sufficient force to close and secure the door (latch speed). Without fluid, the spring would expand rapidly and the door would slam.
The standard “streamline” or modern surface-mounted door closer operates using fluid in a rack-and-pinion spring-loaded piston mechanism. When the door is opened, the arm assembly rotates a geared spindle that moves a gear driven piston, compressing the main spring and forcing fluid into the area previously occupied by the piston. The spring pressure increases as the door is opened. The farther the door is opened, the greater the spring pressure. As the door is closing, the spring expands and exerts pressure on the piston. As the piston moves back, fluid is forced back to the area surrounding the spring. The valves that control the movement of the fluid as the spring expands determine controlled opening and closing of the door. If fluid is permitted to move too quickly, the door will slam. If fluid is restricted too much, the door will not close and latch.
Surface-mounted door closers were initially available with a specific spring power force. The sizes ranged from one to six. For example, a number two door closer is designed for lightweight interior doors. As the weight and height/width of the door increased, so did the size number of the spring force required.
Then manufacturers introduced adjustable sized surface-mounted door closers whose spring force could be adjusted to different sizes, eliminating the need to carry different sized door closers. Adjustable sized door closers vary by manufacturer and model. There are adjustable spring power door closers whose adjustable range is from size 1 through 6 with additional adjustment of more than 50 percent over size 6. Some manufacturers have adjustable closers from sizes 3 through 6. Door closers adjustable from sizes 1 through 4 comply with Americans With Disabilities Act (ADA) requirements for handicapped access.
To be ADA compliant, an interior door cannot have an opening force of more than 5 pounds. In addition, an ADA compliant door closer must adjust the sweep to take at least three second from an open position of 70 degrees to move to a point 3 inches from the latch.