Von Duprin 9957: Specifications, Functions and Application Guide

The Von Duprin 9957 is a wide stile, grooved case surface vertical rod exit device with a three-point latching system that engages the door at the center case, the frame head, and the floor simultaneously. Certified to ANSI A156.3 Grade 1 and UL listed for both panic hardware and fire hardware applications, it covers single and double door openings including mullion configurations, accommodates doors from 2 feet 4 inches to 3 feet wide, and ships with all three functions - EO, DT, and NL - field selectable at installation. This guide covers every specification, every function, every option code, and every installation detail worth confirming before the order ships.

Von Duprin 9957 vs 9857: One Difference That Actually Matters on Site

Both devices share the same functional platform, the same dimensional specifications, the same function codes, and the same options. The single physical distinction is the mechanism case. The 9957 has a grooved mechanism case. The 9857 has a smooth mechanism case. That is the complete difference between the two model numbers.

The practical implication: grooved cases offer a grip surface along the push pad housing, which makes the 9957 the preferred specification in high-use institutional environments - schools, hospitals, government buildings - where staff push the bar hundreds of times daily with wet or gloved hands. Smooth cases are specified where a cleaner architectural appearance is the priority. Neither affects latching performance, load rating, or compliance status.

Both are part of the Von Duprin 99 Series. "Wide stile" refers to the wider push pad housing width that accommodates broader door stile constructions common in heavy commercial and institutional hollow metal door assemblies. The 99 Series sits above the 98 Series in Von Duprin's exit device hierarchy - same function codes, same options, wider profile.

The Three-Point Latching System: Bolt Dimensions and Closing Geometry

A standard rim panic device latches at one point - the center case bolt engaging the door frame strike. The 9957 latches at three. Understanding the geometry matters when the opening requires forced-entry resistance or tight perimeter sealing.

The center case carries a deadlocking rim bolt with a 3/4-inch (19mm) throw. The top and bottom vertical rods each terminate in a deadlocking anti-friction bolt with a 5/8-inch (16mm) throw - the top rod engaging the head strike, the bottom rod engaging the floor strike. All three bolts engage simultaneously when the door closes, distributing lateral load across the full door height instead of concentrating it at the center case alone.

The vertical rods are 1/2-inch square tubing. Standard rods accommodate a 7-foot door height. Top rod length is 34-15/16 inches (887mm). Bottom rod length is 31-1/2 inches (794mm). For doors over 7 feet, extension rods are available in 1-foot (205mm) and 3-foot (914mm) increments. For 8-foot and 10-foot doors, a one-piece top rod eliminates the joined extension rod entirely. The device centerline sits at 39-13/16 inches (1,011mm) from the finished floor - the ADA-consistent mounting height for accessible egress hardware.

The 9957 covers double door openings with or without a mullion. On mullion applications, the center bolt engages the mullion strike rather than the door frame, with top and bottom rods engaging head and floor strikes as on a single door. Vertical rod and latch guards are available to protect the bottom rod from impact by carts, gurneys, or pallet jacks on high-traffic openings.

Door Compatibility, Cutouts and Fasteners

The 9957 fits hollow metal doors prepped with standard 86 or 161 cutouts - the two most common factory punch configurations in commercial hollow metal door production. Doors from 1-3/4 inches to 2-1/4 inches (44mm to 57mm) thick in both metal and wood construction are covered by the standard screw pack included with the device.

For top and bottom latch attachment, the device ships with 325 SNB sex bolts as standard. The 325 SNB accommodates doors at the standard 1-3/4-inch thickness. For doors at or near the 2-1/4-inch upper limit, the optional 425 SNB provides additional thread engagement in thicker door material. This detail is missed on most hardware schedules and only surfaces during installation when the standard bolt cannot pull the latch housing flush.

The 9957 is non-handed in EO, DT, and NL functions, which simplifies ordering on projects where door handing changes during construction. Handing becomes relevant only when the SD (Special Dogging) or SS (Signal Switch) options are added - both of which require directional installation.

Function Codes: Field Selectable Without Factory Modification

The 9957 ships from the factory with all three standard functions installed simultaneously. The installer selects the required function on site.

EO (Exit Only) removes all outside trim. The door opens from the inside by depressing the push bar only. No outside lever, no key cylinder, no credential. Standard on stairwell doors, fire exit corridors, and any egress opening where entry from outside is not permitted. Most common specification for the 9957EO.

DT (Dogging) allows a hex key or cylinder to hold the push bar in the retracted position, converting the device to push-pull operation. Not available on fire-rated assemblies. Specified on non-rated interior openings where free two-directional traffic is needed during operating hours.

NL (Night Latch) adds an outside cylinder that retracts the center latch bolt for key-controlled entry. The latch only - not the vertical rod bolts - is retracted by outside key operation. For TP (thumbpiece), K (key only), or L (lever) outside trim functions, the installer removes the NL drive screw from the device body and installs the appropriate outside trim. This is a field operation, not a factory configuration.

Option Codes: What to Specify and When

The 9957 supports the following factory and field options. Specifying them correctly before the order ships is faster than ordering a replacement:

AX (Accessible Device) - Certifies push pad force at or below 5 pounds. Required on any ADA-accessible means of egress under 2010 ADA Chapter 404.2.7 and California Building Code Chapter 11B-309.4. Non-negotiable on accessible egress routes.

CX (Chexit Delayed Egress) - 15-second delay after an exit attempt triggers a local alarm, meeting NFPA and IBC delayed egress requirements. Specified in retail, assisted living, and memory care facilities where controlled exit delay is permitted by the local Authority Having Jurisdiction.

ESL (Emergency Secure Lockdown) - Enables local lockdown where access control is present. Specified in K-12 schools, university buildings, and institutional facilities with active shooter response protocols requiring room-level lockdown without central system dependency.

LX (Latchbolt Monitoring) - Signal switch reports latchbolt status to an access control or alarm panel. Used when the panel needs positive confirmation that the door is latched, not just closed.

PN (Pneumatic Latch Retraction) - Air-actuated latch retraction for environments where electrical devices are prohibited: chemical processing, certain laboratory spaces, and classified areas.

QM (Quiet Mechanical) - Damper-controlled re-latching reduces closing impact noise. Specified in libraries, healthcare patient rooms, and recording facilities where repeated door impact noise is a facility management issue.

GBK (Glass Bead Kit) - Adapts the device for installation on glass doors with glass bead construction. Required when the 9957 is specified on aluminum storefront or frameless glass openings.

LBR (Less Bottom Rod) - Ships the device without the bottom vertical rod for openings where a floor strike cannot be installed: raised thresholds, floor drain locations, and certain accessible floor configurations.

The 9957 also carries a WS (Weather Shield) designation for installations meeting ICC 500 (2020) storm shelter certification - a specification requirement in tornado and hurricane shelter facilities where exit hardware must perform under extreme wind pressure loads.

Finishes and the Antimicrobial Specification

Available finishes: US3 polished brass, US4 satin brass, US10 satin bronze, US26 polished chrome, US26D satin chrome, US26D-AM antimicrobial satin chrome, US28 satin aluminum, 313AN dark bronze.

The US26D-AM antimicrobial finish carries an EPA-registered antimicrobial agent embedded in the surface coating, confirmed to inhibit bacterial and fungal growth between cleaning cycles. It is specified in healthcare facilities, food processing environments, and any occupancy with infection control protocols that extend to door hardware surfaces. The antimicrobial designation applies to the finish only - not to internal components.

Why American Locksets Is the Right Source for the Von Duprin 9957

The 9957 does not arrive on site in isolation. On any complete door schedule it ships alongside trim, strikes at the head, floor strikes for the bottom rod, closers sized to the door, and on paired openings, a coordinator. Getting all of it from one authorized Allegion dealer in a single order eliminates the parts-arriving-separately problem that delays installations and drives last-minute substitutions.

American Locksets has supplied Von Duprin hardware from authorized Allegion distribution since 2001. Every Von Duprin 9957 ships with a valid manufacturer warranty through official distribution channels. The full 98/99 Series - rim, concealed vertical rod, and surface vertical rod configurations - is stocked through our exit hardware section. For projects where the 9957 integrates with access control, the electronic hardware section covers power supplies, request-to-exit devices, and electrified hardware that ship alongside it. Where an electric strike is specified on the active leaf of a paired opening carrying the 9957 on the inactive, both ship from one order.

Same-day shipping from multiple US warehouses. Call 877-471-4870 with the door width, height, function code, finish, and which options the project requires. We verify the specification before the device ships - not after it arrives on site.

Conclusion

The Von Duprin 9957 is a wide stile, grooved case surface vertical rod exit device with a three-point latching system rated ANSI A156.3 Grade 1 and UL listed for both panic and fire hardware. Three bolts - center, head, floor - engage simultaneously. Field-selectable EO, DT, and NL functions cover every standard egress application without a factory return. Standard rods reach 7-foot doors; extensions and one-piece rods cover doors to 10 feet. Eight option codes - including AX for ADA compliance, CX for delayed egress, and ESL for lockdown - cover every occupancy requirement. American Locksets carries the Von Duprin 9957 from authorized Allegion stock with same-day shipping. Call 877-471-4870 to confirm the spec.

Frequently Asked Questions

What is the difference between the Von Duprin 9957 and 9857? 

The 9957 has a grooved mechanism case. The 9857 has a smooth case. Dimensions, functions, options, and ratings are identical across both.

What does three-point latching mean on the 9957? 

The door latches at three points: center case rim bolt at 3/4-inch throw, top vertical rod bolt at 5/8-inch, bottom vertical rod bolt at 5/8-inch - simultaneously on every close.

What door sizes does the Von Duprin 9957 fit?

 Doors 2 feet 4 inches to 3 feet wide, 1-3/4 to 2-1/4 inches thick. Standard rods cover 7-foot door heights. Extension and one-piece rods cover doors to 10 feet.

Are EO, DT, and NL functions field selectable on the 9957?

 Yes. All three ship simultaneously and are selected on site. For TP, K, or L trim, remove the NL drive screw and fit the appropriate outside trim - no factory return.

Can the Von Duprin 9957 be installed on double doors with a mullion? 

Yes. The 9957 is compatible with single and double door openings including mullion configurations. The center bolt engages the mullion strike in place of the door frame strike.

What is the AX option on the Von Duprin 9957?

 An accessible device certification confirming push pad force at or below 5 pounds. Meets 2010 ADA Chapter 404.2.7 requirements for accessible means of egress.

Where can I buy the Von Duprin 9957?

 American Locksets stocks the Von Duprin 9957 from authorized Allegion distribution with same-day shipping. Call 877-471-4870 to confirm function, options, and finish.

Published by the American Locksets Hardware Team. Authorized Allegion Dealer, Est. 2001, Monroe, NY.