STI (STI-1280)

The STI STI-1280 is a polycarbonate backplate accessory for the STI Stopper II and Weather Stopper series of manual pull-station covers. First, the installer mounts the backplate to the wall. Then the Stopper II or Weather Stopper cover attaches over it. As a result, the cover mounts cleanly on uneven, irregular, or out-of-plumb surfaces that would otherwise gap or twist the cover.

What the STI STI-1280 is built for

Block walls, brick, stucco, and weathered exterior surfaces rarely present a flat mounting plane. However, mounting a Stopper II or Weather Stopper cover directly to an uneven surface gaps the gasket and compromises the seal. Therefore, the STI-1280 backplate provides a flat, even mounting surface that lets the cover sit square against its sealing edge.

Verified STI STI-1280 specifications

• Type: Polycarbonate mounting backplate accessory
• Compatibility: STI Stopper II series and STI Weather Stopper series manual pull-station covers
• Recommended use: Uneven or out-of-plumb mounting surfaces; weather-exposed installations
• Recommended pairing: Strongly recommended with all Weather Stopper models
• Sealing: Gaskets (supplied with Weather Stopper models) are required to maintain a proper weather seal in outdoor installations
• Material: UV-stabilized polycarbonate
• Operating range: Polycarbonate working properties -40° to 250°F (-40° to 121°C)
• Warranty: Three-year guarantee against polycarbonate breakage in normal use

When STI-1280 is required

Indoor installations on drywall or smooth-painted surfaces usually do not require the STI-1280. However, exterior installations on block, brick, or stucco are different. Specifically, STI recommends the backplate on every Weather Stopper installation to maintain the rated weather seal. Furthermore, any indoor installation on an uneven surface (older masonry, textured panels) benefits from the flat mounting plane.

Application context

Exterior pull-station installations at loading docks, parking structures, and outdoor egress points are the most common use. In addition, the backplate is part of the recommended kit on every Weather Stopper installation per STI literature. However, the STI-1280 is an accessory; the pull-station cover itself is sold separately.

Need help selecting the right part or verifying compatibility? Our team supports thousands of commercial fire alarm installations every year. Call us at 1-888-557-0558 or email sales@lifesafetycom.com for application guidance, lead-time updates, or volume pricing.