This is my third draft script for an upcoming whiteboard animation video. Your comments on the previous scripts (panic hardware, classroom lock options) have been very helpful. Please let me know if there is anything I should add or change for this script on door closer arms. If you haven’t seen the whiteboard animation about how a closer works, you can check it out here.
Door Closer Arm Options [Draft Script]
Most door closers used today are surface-mounted closers with a double-lever arm. These closers fall into two categories – application-specific, and universal. A universal closer is best when the field conditions are unknown, or when flexibility is a top priority. Application-specific closers give the specifier and supplier more control over how the door closer is mounted, rather than leaving it up to the installer to decide.
A universal door closer is packaged with everything needed to install the closer three different ways – parallel arm, top jamb, or regular arm – also called hinge side mount. The LCN 1000 series, 4030 series, 4040XP, and the 4050 series are universal closers.
The first decision to be made when installing a universal closer is which side of the door the closer will be mounted on – the push side or the pull side. Closers should be mounted on the interior side of exterior doors, and for interior doors the closer should be mounted on the side of the door that is least exposed to public view.
A parallel arm closer is mounted on the push side of the door, and the arm is parallel to the frame when the door is closed. When using a parallel arm closer it’s important to make sure the top rail of the door is large enough to mount the closer to – otherwise you may need a drop plate.
A top jamb closer is also mounted on the push side but the closer body is on the frame and the arm is perpendicular to the door. The top jamb mounting can be used on a door with a smaller top rail than a parallel arm closer, but the perpendicular arm may be problematic in locations prone to vandalism.
A regular arm closer is mounted on the pull side of the door. With this mounting type, the closer is mounted on the door and the arm is perpendicular to the frame.
An application-specific closer is designed for use in a specific mounting configuration – either parallel arm – like the LCN 4110 series, top jamb – the LCN 4020 series, or regular arm – the 4010 series. LCN’s high security closers are also application-specific.
A benefit of using an application-specific closer is that the closer arm only has one job to do. The parallel arm in particular is much different for an application-specific closer which has an extra duty – or EDA arm, versus the universal arm which is attached to a parallel arm bracket with screws. The EDA arm is the standard arm for the LCN 4110 series. Extra duty arms and other optional arms are also available for universal closers, but using a specific arm with a universal closer will mean that the closer can only be mounted in that one configuration.
A hold-open arm holds the door open at a predetermined degree of opening. Mechanical hold-open arms are not acceptable for use on a fire door assembly, but electronic hold-opens may be used if released by the fire alarm system or a smoke detector. A fusible link arm is a hold-open arm that incorporates a link which melts when it is heated. These were originally used as hold-open arms for fire doors, but today’s codes require hold-open devices used in most fire door locations to be smoke-activated.
A CUSH-N-STOP or “CUSH” arm is a parallel arm with a built-in stop to prevent the door from opening past a certain point. A hold-open controlled by a thumbturn may also be incorporated, making it an HCUSH arm.
Another top of stop arm has a spring-loaded stop rather than the dead-stop provided by the CUSH arm. This is called a Spring-CUSH or SCUSH arm. An SCUSH arm with a thumbturn hold-open added is an S-H-CUSH arm.
LCN has a library of thousands of special templates to address just about every application imaginable. From long arms used when there is a deep reveal, to custom mounting brackets for arched doors and other special details, or templates that coordinate the closer mounting with an overhead stop – the engineers at LCN will do their best to help.
If you have a special application or need help selecting the correct closer, contact your local Allegion representative.