As unglamorous as they might seem, electric strikes have had a leading role in the electronic locking hardware industry for a long time. They are a cost-effective alternative to electrified lock mechanisms in applications where the latter wouldn’t be a practical solution.
All electric strikes work fundamentally in the same way. By electronically controlling the movement of the “keeper” (sometimes referred to as a “gate”) they allow the door to open without manual retraction of the latch bolt. They’re different from traditional lock strikes in that the keeper moves, rotating on a pin or pins. The strike provides access by allowing the latch bolt to travel through the keeper. With the door in the closed position, the latch resides inside the cavity of the strike, having the flat side of the latch resting against the keeper.
So, how do you choose the right electric strike for your application? Consider these primary factors when selecting which electric strike will serve your purposes best:
What is the door made of? For stability, wood frames normally need longer face plates. Hollow metal doorframes, if filled with grout, could make installing an electric strike difficult. Is it a single or double door? This affects how the electric strike will need to be mounted. Is it an interior or exterior door? Security and durability requirements will typically be more demanding on doors to the outside world.
Level Of Security Required
When only light security, with no specific holding force, is needed, a low cost Grade 2 strike may be adequate. When security is paramount, you may need a strike with a minimum holding force of 1,500 lb. (or more in extreme circumstances). 1,500 lb. holding force and a minimum 500,000 cycles endurance, would meet ANSI/BHMA Grade 1 applications.
Type of Lockset And Latch Bolt Dimensions
You’ll need to ensure the electric strike you choose is compatible with the make and model of the lockset on the door. Refer to the lockset manufacturer’s compatibility chart for the specs the electric strike will need to accommodate. For example, always check the center line location of the latch bolt vis a vis the location of the strike in the frame or door, ensuring that the latch has a clear path to the cavity of the strike.
While the majority of electric strikes today are 24 VDC, both 12 and 24 VAC options exist, as well. It is wise to consider filtered and regulated power sources where able and practical. These sources of power extend life to the operation of the strike. However, transformers are widely used and will provide adequate power to the strike. Also to be noted is that AC power, by its very nature, will cause the strike solenoid to “chatter”, which is audible at the strike and can be quite annoying. Each application is different so choosing AC or DC power is critical in the selection process.
Doors connected to alarm systems and entry buzzers will require electric strikes with the capability to work in conjunction with those additional electronic elements.
On fire-rated doors, electric strikes must be “fail secure,” ensuring that by default the door goes into the locked position when power is removed. “Fail safe” electric strikes, which go into an unlocked state when no power is applied, do not meet code requirements for fire doors. Of note, fire rated pairs of doors having an electric strike mounted in the “inactive” leaf, will require strikes to have a special listing. Typically, strikes in this unusual application, if certified, will not exceed a 90 minute listing.
Your choice of electric strike might also depend on whether or not latch bolt monitoring or locked status monitoring is required by the property manager or owner. Most security applications will require some sort of monitoring.
Locking In The Right Electric Strike
If you’re not sure of which electric strike will meet your application’s needs (or if an electric strike is even the right solution), consult an architectural hardware consultant at DORMA for guidance. With DORMA’s wide variety of electric strikes to match the security and operational needs of vast private, public, and commercial buildings, our team has expansive expertise and experience to help you select the right hardware under any circumstances.