Closers Are Key to Effective Entry Systems
Door closers/controllers are the “heart of the opening” because they protect the people and assets on the other side, while playing a major role in energy conservation.
Protecting the facility opening is one of a door closer’s main functions, especially in high use/abuse situations. High-cycle doors, including those at malls, hospitals, stadiums, auditoriums, schools, and universities, encounter abuse from more forceful opening and backchecking. They are some of the most highly used and abused components within any facility, yet they must enable smooth traffic flow while maintaining safety, security, and the overall facility experience.
|The overhead stop is visible with the door open. Used here with a concealed closer, it protects the door, hinges, and closer from abuse or misuse.|
High winds or pressure differentials require greater closer force to protect exterior doors from severe damage. Heavy-duty, concealed, or surface-mounted closers offer an extra measure of protection, but their use must be balanced with the need to avoid making doors too difficult to open. Proper closer adjustment plays an important role in achieving the balance needed in these situations. A backcheck selector valve, delay function, or other adjustments make it possible to tailor different stages of closer operation to the needs of a specific opening.
Some closers use a pressure-relief valve to prevent damage to the closer under overload conditions that may be severe enough to cause cracks in the closer cylinder. Closers with cast-iron cylinders generally will not require pressure-relief valves because the material’s innate strength resists cracking, ensuring smooth opening and closing.
Adding an overhead stop helps protect the closer and the rest of the opening against excessive force. Also important is proper installation and adjustment of the closer itself.
Protecting people from the door can include preventing accident or injury from a door that closes too quickly, minimizing difficulties that children or frail adults may have in opening the door, and meeting accessibility guidelines for those with disabilities.
Closers adjusted too strong to meet ADA guidelines will also be difficult for other people to open. If conditions permit, it may be possible to accommodate ADA compliance by adjusting the closer force to Size 1, but in most cases, power door operators are the best option to meet these needs. Typically, one powered door in a bank of doors may be all that is required. In addition to serving people with disabilities, it can add convenience for parents with strollers or people with armloads of packages.
Properly adjusted conventional closers on all other doors ensure that they close and latch. Seasonal adjustments used to be a common attempt to meet these problems, including those on exterior doors exposed to temperature extremes. Today, the availability of closers with all-weather fluid has made this ritual unnecessary.
In addition to ease of use and proper closure, ensuring security is a critical closer function. No matter how sophisticated or expensive the locks, latches, exit devices, card readers, and electronic security systems, if the door does not close properly, latching will be inconsistent and security compromised. This puts people and assets within the building at risk. A facility director can spend hundreds of thousands of dollars on electronic access control, magnetic locking, and proprietary keying systems, only to find these measures wasted because the doors do not close so they can latch and lock.
Security problems may arise from improper installation of closer mounting and adjustment, or with related hardware. If latch bolt guards are not aligned properly, friction may be created to prevent the door from latching. To prevent closer adjustment tampering and to enhance security, closers can be equipped with metal covers mounted with Torx machine screws.
Manufacturers are working constantly to improve performance and enhance closer functions to provide greater security. New designs now being developed will self-adjust as environments or operating conditions change.
Door closers provide environmental control as they keep doors closed to maintain internal environments inside. It makes little sense to waste money and compromise comfort levels because heated or conditioned air leaks outside when a door doesn’t securely close. Temperature or weather extremes that enter a building through a partially open door can cause damage, as well as discomfort. Strong winds can cause damage to uncontrolled doors. Inside a building, closers maintain pressure differentials in areas including stairwells and vestibules.
Leaking closers are an environmental problem and a potential hazard to those entering and exiting a doorway. When oil drains from the cylinder, the closer’s ability to control the door is lost. If this occurs, the door swings freely and could lead to personal injury and costly damage to the door and frame. In addition, oil inside a closer can drip down and make floors slick.
Leaks are typically caused by either an o-ring malfunction or cylinder cracks. An o-ring malfunction often results from excessive use or abuse of the opening that causes the o-ring seal to wear and create a leak point. The pinion seal can also malfunction in situations with an aluminum closer with steel pistons. The rigid steel piston wears on the softer aluminum body and creates tiny metal contaminants. These abrasive fragments can quickly wear an o-ring, creating a potential leak point. Another potential malfunction is cracking in the closer cylinder body. Abusive operation can create excessive internal pressure in the closer, causing the cylinder body to crack.
Several options exist to solve a leak problem. One is to move to a more durable material structure such as cast iron. Another option includes moving to the next model size in durability. One manufacturer offers a heavy-duty cast iron closer with a 10-year, no-leak guarantee.
Fire/life safety is a classic conflict between two important factors. For door closers, one of the most common problems is with fire-barrier doors, particularly for stairwells. As with security, if the door doesn’t latch properly, the opening is not protected. The problem can be especially acute with air conditioning operating, which creates a large pressure differential between a stairwell and hallway. This has an effect similar to a strong wind and calls for careful closer selection, installation, and adjustment to ensure compliance to the fire codes and ADA.
Fire- or smoke-barrier doors must remain closed to be effective. However, to allow traffic to flow, some are held open by electromagnetic holders wired into the building’s fire alarm system or have internal detection capability. There are several options available that allow one to hold a fire door open and meet fire codes. Options include magnets wired to the central fire panel or integrated closer/detector. One option accomplishes the same goal of holding open a fire door without the need to pull wires and provide a power supply. The battery-powered Sensaguard holder/release smoke detector, manufactured by Glynn-Johnson, Indianapolis, IN, allows fire doors to remain open for easy passage, while releasing doors in an emergency through its built-in smoke detector. The device, when combined with a door closer, is an attractive alternative for retrofit and remodeling applications.
Visual appeal doesn’t have to be sacrificed as door closers are selected to provide all of the functions discussed and also comply with building codes. An appealing opening is easy to achieve.
One approach is to use a concealed closer mounted out of sight in the door or frame. These are available in heavy-duty models for high-use/high-abuse applications, as well as for fire-rated doors with openings as large as 180 deg. Manufacturers offer a broad range of cover designs including slim-line-, full-, and designer-series covers, and as many as 150 or more different powder-coated finishes. Metal covers add security and improve appearance, especially when plated. One manufacturer offers a bright metal metallic finish, an economic alternative to plating, that still offers similar aesthetics. When appearance is a concern, it is advisable to work with a manufacturer that offers full suites of hardware that coordinate style and finish, including mortise locks, levers, exit devices, and other visible components.
One method to achieve a consistent appearance where applications vary through a facility is to use similar covers but different closer bodies. A building may use heavy-duty closers on doors that are frequently used, but less expensive models on janitorial closets. To unify appearance, it may be possible to use the same cover design on all units. Whenever a standard design does not answer the need, check with the manufacturer to see if there are alternative solutions.