The Builders Hardware Manufacturers Association (BHMA) has
published the American National Standards for
electromagnetic locks (ANSI/BHMA A156.23-2004) and delayed
egress-locking systems (ANSI/BHMA A156.24-2003). The latter
requires that the delay period of such systems not be
adjustable in the field and shall not exceed the time
permitted by the authority having jurisdiction (AHJ).
Maximum delay time for opening a door is 15 seconds, with a special exemption by the AHJ required for a maximum delay time of 30 seconds, according to BHMA.
This standard also includes performance criteria for functional, cycle, operational, failsafe and overload requirements.
ANSI/BHMA A156.23-2004 explains standard numbering systems for identifying electromagnetic locks. BHMA cites as an example, “E18501-1000.” The first letter indicates BHMA product section. The first numeral denotes whether the lock is designed for all except indoor-only (0) or indoor-only (1). The second number identifies the type of product, with “8” referring to electromagnetic locks.
The third and fourth numbers denote product types based on mounting location and whether they are direct pull or shear designs. The fifth number indicates the grade of the item. The number after the dash indicates the appropriate level of holding force in 500-pound increments.
BHMA’s example of E18501-1000 describes an indoor-only, type 50 grade 1 electromagnetic lock with a 1,000-pound holding force rating.
