Everything You Need To Know About Door Hardware: Part 2

Jun 7

This article briefly explains cylindrical, mortise, and deadbolts. Code excerpts will be referenced where applicable.

Cylindrical

Found in 2018 IBC 1010.1.9.4. Cylindrical locks are the type where the entire locking mechanism is located within the footprint of the rose. For installation they only require the typical 1.5” or 2.125” face bored hole, with corresponding edge bore for the latch. These locks are the most common. As such they are easily procured, cheaper to purchase, come in a variety of grades, functions, finishes, and styles. However, due to their simple mechanism they have limited features which the mortise lock expands upon.

Mortise

Found in 2018 IBC 1010.1.9.4. A mortise is a hole or recess cut into a part. The mortise lock mechanism resides in this recess cut into the door. These types of locks require doors to be prepped for this mortise. These locks are the highest quality and are designed for heavier duty uses. They can come with several options that should be carefully selected when specifying. Options include deadbolts, latches, roses, escutcheon, indicators, and specialty functions. Additionally, they do come in all grades, typical functions, finishes, and styles. Due to their higher quality and options they are more expensive than cylindrical locks.

Deadbolts

Found in 2018 IBC 1010.1.9.5, when an additional level of security is required a deadbolt can provide the necessary latch material. It can come from either a separate mechanical lock or integrated into a mortise lock body. Note that doors that are part of the means of egress must be able to be unlatched with one operation, see 2018 IBC 1010.1.9.6. One operation is the twisting of the handle. Therefore deadbolts along with cylindrical locks are not compliant. On mortise locks the operation of the handle also retracts the deadbolt.