Manual pull stations are required life safety devices in virtually every commercial, institutional, and multi-family building — but they’re also vulnerable to accidental activation, vandalism, and tampering. The STI Stopper II pull station cover is the industry-standard solution for protecting pull stations while maintaining accessibility and code compliance. Whether you’re protecting a pull station in a school hallway, a hospital corridor, or a warehouse, STI covers are a cost-effective way to reduce false alarms and protect equipment.
Why Pull Station Covers Are Essential
Manual fire alarm pull stations are intentionally designed to be easy to find and activate in an emergency. That accessibility, however, also makes them targets for mischief and accidental activation. Common false alarm scenarios include:
- Children and teenagers pulling stations as pranks
- Accidental activation during cleaning, maintenance, or moving activities
- Curious individuals who don’t understand the consequences
- Vandalism in high-traffic or unsupervised areas
Each false alarm costs time, disrupts operations, may incur fire department response fees, and desensitizes building occupants to genuine alarm conditions. Pull station covers add a layer of friction — a cover that must be lifted or removed before the station can be pulled — without creating a meaningful barrier to activation in a real emergency.
STI Stopper II Model Overview
STI-1130: With Horn and Spacer
The STI Stopper II STI-1130 is the most popular model, featuring a built-in audible horn that activates when the cover is lifted. When someone raises the cover to access the pull station, the cover’s self-contained horn sounds an alert — providing immediate audible notification to nearby occupants and staff that the pull station is being accessed.
The STI-1130 also includes a spacer plate that accommodates pull stations with surface-mounted back boxes, ensuring a flush, professional appearance on most standard installations. The horn operates on a small internal battery (typically a 9V alkaline, included), so no wiring is required — just mount and go.
STI-1130 key features:
- Audible horn activates when cover is lifted (~105dB)
- Includes spacer for surface-mount pull stations
- Clear polycarbonate construction for full pull station visibility
- Easy-open front panel for authorized access
- Mounting hardware included
- Indoor use rated
STI-1230: Without Horn
The STI-1230 is the silent version of the Stopper II — identical in form and mounting to the STI-1130, but without the audible horn. This model is appropriate for settings where the horn alarm would be disruptive or where visual deterrence alone is sufficient, such as secured facilities with CCTV coverage or areas where staff are always present.
The STI-1230 is also used in environments where local codes or building owners prefer a clean deterrent without the horn component. It’s available with or without the spacer, depending on installation requirements.
Selecting the Right Model for Your Pull Station
Choosing the correct STI cover requires matching the cover to both the pull station model and the mounting configuration. Key selection factors:
- Pull station brand: STI makes covers sized for specific pull station brands. Verify the cover is compatible with your pull station — Simplex, Notifier, Siemens, Gamewell, Edwards, and other brands have different face dimensions.
- Flush vs. surface mount: If your pull station has a surface-mount back box, select a model with the spacer included (STI-1130) or order the spacer separately.
- Horn vs. no horn: As described above, choose based on your specific environment and deterrence goals.
- Indoor vs. outdoor: Standard STI covers are rated for indoor use. For outdoor pull stations, verify the cover’s environmental rating matches the installation location.
ADA Considerations
The Americans with Disabilities Act (ADA) and IBC accessibility standards require that manual fire alarm pull stations be operable with one hand, with a maximum activation force of 5 lbs. STI pull station covers are designed to not impede ADA-compliant pull station operation — the cover lifts easily with one hand before normal pull station activation. However, during installation, verify that the specific cover + pull station combination does not increase operational force beyond the required limits.
Installation Tips
- Identify the pull station model and mounting configuration before ordering the cover.
- Install the cover so the pull station remains clearly visible through the polycarbonate front panel.
- If using the STI-1130 with horn, install the battery before mounting and test the horn by lifting the cover.
- Ensure the cover does not obstruct the pull station’s operating handle in any way.
- Label the cover if required by the AHJ — some jurisdictions require signage indicating the device is a fire alarm pull station.
- Replace the horn battery annually as part of your fire alarm inspection program.
Order STI Pull Station Covers
The STI Stopper II STI-1130 is in stock at Life Safety Consultants for fast shipment. For facilities with multiple pull stations, ordering in quantity reduces per-unit cost. Browse our complete fire alarm accessories catalog for pull station covers, smoke detector dust covers, and other protective accessories for life safety equipment.
