Interior doors have a five-pound minimum opening force required by federal law. The exception is interior doors labeled “in the means of egress” must close and latch. National Fire Protection Act (NFPA) 101 paragraph 18.104.22.168.5 states that a door must have 30lb/sf. maximum opening force to put door in motion and 15lbsf. maximum opening force to reach required width. However, California Building Code (CBC) places a maximum of 15 pounds opening force. The interior doors that are not “in the means of egress” must be five pounds.
Important: The operating force restrictions are tested on the moving door at approximately three inches from the closed position and measured 30 inches from the hinge.
If you are from a state that has different operating requirements, please let me know and I will include the information in the magazine. Thanks.
To improve closing efficiency, Norton introduced the Cam Action Door Closer. The Norton 2800ST Series Grade 1 Door Closer uses a cam lobe operating mechanism. Unlike the gear-driven piston type closer, the cam lobe closer, according to Norton, “is more efficient, between 70 and 80 percent, providing up to four pounds closing force for a five pound opening force.” The Norton 2800ST series is equipped with a size one through six adjustable power spring . The spring adjustments can provide operating force sufficient for any required pound setting.
The Norton 2800ST Series Cam Action Door Closers are designed to operate on maximum door weight of 250 pounds. For interior door applications, the maximum door width is 54 inches.
The Norton Cam Action Closers uses an egg-shaped cam lobe that takes the place of the geared spindle. There are two spring-loaded pistons, one on each side of the cam. The stronger, main spring is compressed by a piston as the door is opened. The second piston has a light spring that keeps the piston's roller against the cam even in the open position. Fluid flow controls the speed of movement.
The cam rotates slightly less than one half of a revolution, giving a maximum door opening for standard applications of not much more than 110 degrees. This results in about one-half inch total movement of the main piston. This is approximately one-third the distance traveled by a standard rack-and-pinion type door closer piston. To accommodate this shorten closing cycle, the cam action door closer operates using more accurate fluid control.
The spindle has an internal spline to time the arm instead of an external square or hex. A splined spindle offers more positional options for preloading the closer and allows for lower setting when the door needs to meet low opening force requirements such as American's with Disabilities Act (ADA). The purpose of pre-loading a closer's arm is to provide sufficient spring pressure at the end of the closing cycle for the door to close and latch or to keep the door closed when there is no latch mechanism.
The Norton 2800ST Series Grade 1 Door Closers are designed to operate by using a slide track mechanism. Unlike a standard arm assembly having a main arm and secondary arm, the slide track mechanism requires only the main arm. The slide track replaces the secondary arm.
The Norton cam closer uses two different styles of slide tracks. One is designed for the pull side of the door. The mounting holes in this track are on the sides so it can be mounted on the face of the frame. The other slide track is designed for the push side of the door. The mounting holes are in the groove of the track so it can be mounted to the bottom of the jamb. For either application, the closer is always mounted to the door and the slide track is always mounted to the jamb. Slide tracks are available with or without Hold Open.
For Pull Side Applications, the track is mounted onto the face of the jamb with the screw holes located at 1-5/8 inches above the bottom of the jamb. A minimum ceiling clearance of two inches is required above the top of the door.
Mounting the Norton 2800ST Series Door Closer requires more exact measurements. For example, there are four maximum degree of opening angles (85, 90, 100 and 110 degrees), each having a different distance from the center of the hinge or pivot. The distance the slide track is from the hinge/pivot edge of the door determines the maximum opening of the door.