A specification guide to concealed vertical rod (CVR) exit devices, including fire-rated applications, door prep requirements, and comparison with rim exit devices.
This guide answers: When Should You Specify a Concealed Vertical Rod Exit Device Instead of a Rim Exit Device?
Understanding Exit Device Types: Rim vs. Concealed Vertical Rod
Exit devices (also called panic hardware or fire exit hardware) are required on doors serving as means of egress in commercial buildings. The two most common exit device types are rim exit devices and concealed vertical rod (CVR) exit devices. Each type serves the same fundamental purpose — allowing free egress with a single pushing motion — but they differ in how they latch, where they mount, and which applications they are suited for.
Rim exit devices mount on the surface of the door and latch into a strike mounted on the frame jamb at the lock rail height. Concealed vertical rod exit devices are mortised into the door stile, with rods extending vertically to latch points at the top and bottom of the door. The choice between these two types depends on the door configuration, fire rating, aesthetic requirements, and code requirements for the specific opening.
How Concealed Vertical Rod Exit Devices Work
A CVR exit device consists of a push bar or crossbar mounted on the interior face of the door, connected to a mechanism concealed within the door stile. When the push bar is depressed, internal linkage retracts vertical rods that extend from the mechanism to latching points at the top and bottom of the door.
- Top rod: Extends from the device mechanism upward through the door to a latch bolt that engages a strike in the head frame or, on non-fire-rated pairs, a removable mullion
- Bottom rod: Extends downward through the door to a latch bolt that engages a strike in the floor or threshold
- Flush appearance: Because the mechanism and rods are concealed within the door, the only visible component on the push side is the crossbar or touchpad. This provides a cleaner appearance compared to surface-mounted rim devices
- Door prep: CVR devices require a mortise pocket in the door stile, plus top and bottom rod bores through the full height of the door. This door prep is more extensive than what a rim device requires
When CVR Devices Are Required: Fire-Rated Pair Applications
The most common reason for specifying CVR exit devices is fire-rated double door (pair) applications. On fire-rated pairs without a mullion, building codes and UL 10C testing requirements typically mandate that each door latch independently at the top and bottom — which is exactly what a CVR device provides.
Fire-rated door assemblies are tested and labeled at specific ratings: 20-minute, 45-minute, 60-minute, 90-minute, and 180-minute. The exit device must be listed and labeled for the fire rating of the assembly in which it is installed. Not all CVR devices carry all fire rating labels, so the specifier must verify that the selected device is listed for the required rating.
On fire-rated pairs, a rim exit device cannot be used on the inactive leaf because there is no frame jamb to receive the rim strike — the strike would mount to the active leaf, which is not a fixed structure. CVR devices solve this by latching into the head frame and floor, both of which are fixed structural elements.
- Fire-rated pairs without mullion: CVR devices are typically required on both leaves to provide independent top and bottom latching
- Fire-rated pairs with mullion: If a fixed or removable mullion is present, rim devices may be acceptable because the mullion provides a strike-receiving member at the lock rail
- Single fire-rated doors: Rim exit devices are generally acceptable on single fire-rated doors because the frame jamb provides a fixed strike-receiving member
CVR vs. Rim Exit Device Comparison
The following comparison outlines the key differences between CVR and rim exit devices across the most relevant specification criteria.
- Latching points: Rim devices latch at one point (lock rail to frame jamb). CVR devices latch at two points (head frame and floor/threshold).
- Door prep: Rim devices require minimal door prep (surface mount with through-bolts). CVR devices require a mortise pocket in the stile plus top and bottom rod bores.
- Appearance: Rim devices have a visible case on the door face. CVR devices are concealed within the door for a flush appearance.
- Fire-rated pairs: CVR devices are typically required. Rim devices may be used only if a mullion is present.
- Maintenance: Rim devices have fewer internal components and are generally simpler to service. CVR devices require periodic adjustment of the top and bottom rod latching.
- Cost: CVR devices are typically more expensive than rim devices due to the additional mechanism, rod assemblies, and more extensive door prep requirements.
- Weight: CVR devices add less visible bulk to the door face but require a door with sufficient stile width to accommodate the mortise pocket.
Flush Bolt Coordination on Pairs
On double door openings with one active and one inactive leaf, the inactive leaf is typically secured with flush bolts at the top and bottom. When a CVR exit device is specified on the active leaf of a pair, the inactive leaf flush bolts must be coordinated to ensure proper door sequencing and latching.
Automatic flush bolts are commonly used on the inactive leaf so that the inactive door latches automatically when closed, without requiring manual action. The coordinator (a device mounted on the frame head) ensures the inactive leaf closes before the active leaf, allowing both doors to latch in the correct sequence.
Door Prep Requirements for CVR Devices
Specifying a CVR exit device requires coordination with the door manufacturer to ensure the door is prepped correctly. The following prep elements are required.
- Mortise pocket: A routed pocket in the lock stile of the door to receive the CVR mechanism. The pocket dimensions vary by manufacturer and device series.
- Top rod bore: A vertical bore from the mechanism pocket to the top of the door for the top rod assembly
- Bottom rod bore: A vertical bore from the mechanism pocket to the bottom of the door for the bottom rod assembly
- Crossbar mounting holes: Through-holes for the crossbar or touchpad mounting bolts
- Stile width: The door stile must be wide enough to accommodate the mortise pocket. Minimum stile widths vary by device series but are typically 4-1/2 inches or wider
- Header strike prep: The head frame must be prepped to receive the top rod strike, including the correct strike pocket depth and mounting holes
- Floor strike or threshold strike: The floor or threshold must be prepped for the bottom rod strike
How CDF Distributors Supplies CVR Exit Devices
CDF Distributors provides concealed vertical rod exit devices from several manufacturers including Von Duprin, Hager, Accentra, Falcon, Corbin Russwin, and Sargent. They all offer CVR models for different commercial applications and fire rating requirements.
When configuring a door assembly through CDF's ProBuilder tool, the exit device type can be selected as part of the complete hardware set for the opening. ProBuilder coordinates the exit device selection with the door prep, frame prep, and other hardware to ensure compatibility across the full assembly. For fire-rated pairs, ProBuilder can be configured with CVR devices on both leaves along with the appropriate coordinator, flush bolts, and strikes.
Configure Your Door Assembly
CDF's ProBuilder tool allows contractors and facility managers to configure complete door, frame, and hardware assemblies online. During configuration, you can select the specific components discussed in this guide and receive an instant quote.
For assistance or to order a complete door assembly, call (855) 769-9895 or email sales@cdfdoors.com. CDF's sales team is available to help you specify the right components for your project.
Frequently Asked Questions
What is a concealed vertical rod exit device?
A concealed vertical rod (CVR) exit device is an exit device whose mechanism is mortised into the door stile rather than surface-mounted. Vertical rods extend from the mechanism to latch points at the top and bottom of the door, retracting when the push bar is depressed to allow egress. The concealed installation provides a flush appearance on the door face.
When is a CVR exit device required instead of a rim exit device?
CVR exit devices are most commonly required on fire-rated double door pairs without a mullion. On these openings, each door must latch independently at the top and bottom into fixed structural elements (the head frame and floor), because there is no center jamb to receive a rim strike. CVR devices provide this independent top-and-bottom latching.
What fire ratings apply to CVR exit device assemblies?
Fire-rated door assemblies are tested and labeled at 20-minute, 45-minute, 60-minute, 90-minute, and 180-minute ratings. The CVR exit device must be listed and labeled for the specific fire rating of the assembly in which it is installed. The specifier must verify that the selected device model carries the required fire rating label.
What door prep is required for a CVR exit device?
CVR devices require a mortise pocket in the lock stile, a vertical top rod bore to the top of the door, a vertical bottom rod bore to the bottom of the door, crossbar mounting holes, and a stile width of typically 4-1/2 inches or wider. The head frame and floor or threshold must also be prepped to receive the top and bottom rod strikes.
Can a rim exit device be used on fire-rated double doors?
A rim exit device may be used on fire-rated double doors only if a fixed or removable mullion is present to provide a strike-receiving member at the lock rail. On fire-rated pairs without a mullion, CVR devices are typically required because the rim strike has no fixed structure to mount to.
How are CVR exit devices coordinated with flush bolts on pairs?
On pairs with one active and one inactive leaf, the inactive leaf is typically secured with automatic flush bolts at top and bottom. A coordinator mounted on the frame head ensures the inactive leaf closes before the active leaf, so both doors latch in the correct sequence. The CVR device on the active leaf and the flush bolts on the inactive leaf must be specified as a coordinated set.
How do you order CVR exit devices through CDF?
CVR exit devices are available through CDF Distributors via the Banner Solutions distribution channel. You can configure CVR devices as part of a complete door assembly using CDF's ProBuilder tool, which coordinates the exit device with door prep, frame prep, and other hardware. Contact CDF at (855) 769-9895 or sales@cdfdoors.com for assistance.
About This Guide
This guide reflects CDF Distributors' standard specifications and field-tested recommendations used by commercial contractors nationwide. The information is provided for specification and selection purposes. Always verify requirements with the Authority Having Jurisdiction (AHJ) for your project location.
For questions or to order a complete door assembly, contact CDF at (855) 769-9895 or sales@cdfdoors.com. Configure your assembly online at ProBuilder: cdfdistributors.com.
