Name: CISA 52840 90 mm Backset Function A heavy-duty escape lock with automatic bolt (152840900)
Brand: CISA

CISA 152840900 — Official series illustration, not a photo of this exact size variant; consult model specifications. — Official series illustration, not a photo of this exact size variant; consult model specifications.Image source

152840900 backset 90 mm measurement-reference diagram; not a product view — Drawn by this site from the explicit dimensions of the corresponding model; the diagram is not to scale and is not a drilling template.

Lock and fitting dimensions

Dimensions from model documentation
Specifications	Dimensions from model documentation
Backset	90 mm
Faceplate width	22 mm
Centre distance	85 mm

Check the backset, centre distance, faceplate and mounting points against the specific model drawing.

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Specifications

Backset: 90 mm
Faceplate width: 22 mm
Case: Galvanized steel
Latch: Reversible nickel-plated silent construction
Faceplate ends: Square ends
Centre distance: 85 mm
Function: A
Bolt throws: 1
Square spindle: Through spindle
Bolt configuration: Catalogue states automatic release when the door closes
Outside operation: Key operates latch and bolt
Inside operation: Key, handle or escape device operates latch and bolt

Construction and operation of this version

152840900 is an explicit ordering row in the 52840 series with backset 90 mm. This section explicitly describes automatic bolt release on door closing, unlike the A-function version on the same page without a stated automatic action. An escape device can operate both latch and bolt from inside; a key operates them from outside.

How to check installation dimensions

This model's backset is 90 mm, the distance from the specified door-edge faceplate reference to the operating axis. Faceplate width, centre distance and external lock-body depth describe different directions and must not substitute for one another.

For replacement, record the old lock's full number, faceplate-end shape, inside and outside operating components and strike positions; when changing handing or linked rods, confirm interfaces according to the product instructions.

Limitations

Consult the specific installation instructions for the full triggering conditions and direction of operation of automatic release; this page does not infer other operating states from the brief catalogue description.
Series certification and catalogue descriptions of fire or escape applications do not mean this model meets current requirements when installed in any door assembly.
Check accessories against the corresponding model and installation instructions; Cylinders, rods and escutcheons listed as available on request are not standard equipment.

Sources

CISA 2026 English catalogue, PDF page 350 / printed page 346

Manufacturer documents are provided in their original language.

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