When fire alarm control panels, power supplies, or notification appliances need to operate in harsh environments, a NEMA-rated enclosure is essential. Safety Technology International (STI) manufactures the EnviroArmour line of enclosures specifically designed to protect life safety equipment from weather, dust, vandalism, and temperature extremes.
With dozens of sizes and configurations available, choosing the right STI enclosure can be overwhelming. This guide walks you through the key decisions.
Step 1: Choose Your Material — Polycarbonate vs Fiberglass
Polycarbonate Enclosures (EP Series)
STI’s polycarbonate enclosures are lightweight, impact-resistant, and corrosion-proof. They’re ideal for most outdoor and indoor applications where moderate temperature protection is needed.
- Pros: Lightweight, UV-resistant, won’t corrode, transparent options available (window models)
- Cons: Lower temperature tolerance than fiberglass in extreme cold
- Best for: Outdoor fire alarm panels, parking structures, building exteriors, pool areas
Fiberglass Enclosures (EF/EN Series)
STI’s fiberglass enclosures offer superior strength and temperature performance for the most demanding industrial environments.
- Pros: Higher impact resistance, wider temperature range, better UV resistance for long-term outdoor use
- Cons: Heavier, typically more expensive
- Best for: Industrial facilities, rooftops, extreme weather locations, high-security installations
Step 2: Determine the Right Size
STI enclosures range from compact 10″ × 8″ × 6″ units to large 48″ × 36″ × 16″ cabinets. To choose the right size:
- Measure your equipment — fire alarm panel, power supply, or appliance dimensions plus clearance for wiring
- Allow 2-3 inches of clearance on all sides for airflow and cable routing
- Consider future expansion — if you may add modules or batteries later, size up
Browse all sizes: STI Enclosures →
Step 3: Select Climate Control Options
If your enclosure will be exposed to temperature extremes, STI offers built-in climate control:
- A/C + Heat models (W2 suffix) — thermostatically controlled cooling and heating for year-round operation. Essential in locations with >100°F summers or
- A/C only models (W suffix) — cooling with window panel for hot climates
- Ventilation only — fan and filter for moderate climates where passive airflow isn’t sufficient
- Sealed (no climate control) — for indoor or temperate outdoor locations
Step 4: Don’t Forget the Back Panel
Your equipment needs a mounting surface inside the enclosure. STI offers two types of back panels:
- Aluminum (BPA series) — lightweight, corrosion-resistant, easy to drill. Best for most applications.
- Fiberglass (BPF series) — non-conductive, ideal when electrical isolation is needed
Match the back panel size to your enclosure — STI makes panels from 6″ × 6″ to 48″ × 36″.
Step 5: Consider Accessories
Complete your installation with STI accessories:
- DIN rail kits — for mounting DIN-rail equipment inside enclosures
- Swing panel brackets — allow the back panel to swing open for easy equipment access
- Ventilation kits — add filtered ventilation to sealed enclosures
- Replacement locks — rekey or replace enclosure locks
- Pole mount kits — mount enclosures on utility poles or standalone posts
Popular STI Enclosure Configurations
- Small panel protection: EP101006-O — 10″ × 10″ × 6″ polycarbonate
- Mid-size panel: EP242410-O3 — 24″ × 24″ × 10″ polycarbonate with NEMA 3R
- Full-size FACP: EN483612-W2 — 48″ × 36″ × 12″ fiberglass with A/C and heat
Need Help Sizing Your Enclosure?
Not sure which STI enclosure fits your equipment? Contact Life Safety Consultants — tell us what equipment you’re protecting and the environment, and we’ll recommend the right enclosure, back panel, and accessories.
Shop all STI products: STI (Safety Technology International) →
