All doors need some type of hinge mechanism in order to open and close. Most commercial doors are equipped with butt hinges. The door location, size and weight determine the hinge size, base material and number of hinges according to building and local codes and standards. See ANSI/BHMA Standard 156.1, the American National Standard for Butts and Hinges.
Beyond the rules and regulations, the amount of traffic through the door must be considered when installing or retrofitting hinges. Normal wear occurs because of the outward pulling forces (gravity) against the door even when it is closed. Even on a properly installed door, most of the weight and stress is pulling against the top hinge. Over time, a typical three or four butt hinge configuration for a tall, heavy or high traffic door can result in problems closing the door. This usually occurs due to wear on the contacting hinge leafs surfaces. Hinge wear and tear can be accelerated by abuse including opening the door beyond the limit, or when opening or closing using excessive force. “Kickback” can cause the screws in butt hinges to slowly back out. This can result in stripped screws and a sagging door.
Note: Excessive hinge wear is more prevalent on commercial doors equipped with sub standard and non ball bearing butt hinges.
When door closing problems begin to occur, there are two options: replace the worn hinge(s) or replace all of the hinges. An alternative worth considering is upgrading to a continuous hinge. A continuous hinge is a single hinge that runs roughly height of the door. This single length hinge spreads weight of the door further along the hinge’s length instead of concentrating it in three or four locations. With a continuous hinge, the pressure against the door causes it to press against the jamb along the lower portion of the door.
As an additional benefit, a quality continuous hinge requires less force to close the door than the same door equipped with butt hinges. Less force requires less door closer power, beneficial in a building that has closing issues including stack pressure.
Continuous hinges are available in different functions including standard, door edge protection, wide throw and swing clear.
Pin and Barrel
Two basic continuous hinge designs are the “pin and barrel” and the geared continuous hinges. The “pin and barrel” continuous hinge is an offshoot of a heavy gauge “piano” hinge. These many-knuckle hinges incorporate a single “pin” running the length. Door “pin and barrel” continuous hinges are normally made of heavy gauge steel, stainless steel and non-ferrous materials. Standard sizes are 79” to 119” or 10’0”. Continuous hinge length should be 1 inch shorter than door size, according to some manufacturers. For example, a 7’0” door should have a hinge length of 83”.
Continuous hinges are available for different amounts of traffic (cycles) and weight doors. ANSI/BHMA A156.26 establishes requirements for architectural continuous hinges. The latest standard is 2012. Check with each manufacturer for the weight and traffic rating for their “pin and barrel” continuous hinges.
An example of a “pin and barrel” continuous hinge is the Markar 300 Series Stainless Steel Hinge that supports door weight up to 600 lbs., having a four-foot maximum door width. The hinge is manufactured from 14 gauge stainless steel, using 2-inch knuckles whose outer diameter is 7/16” and a .187” diameter stainless steel pin (rod). Nylon (medical) bearings at each knuckle separation provide quiet, smooth, self-lubricating operation. Note: The nylon bearings can be optional for some “pin and barrel” continuous hinges.
Additional options for “pin and barrel” continuous hinges can be a 12 gauge hinge, Teflon-coated pin and built-in edge guards.
Deliver total door service by fixing the real problem — worn hinges — and you’ll make more money and also satisfy a customer by fixing their problem for good.
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The next time you’re called to fix a lock, take a look at the hinge. If you’re unfamiliar with installing geared continuous hinges, you’re missing a profitable opportunity