How to Read a Ceiling Tile Spec Sheet

Every ceiling tile has a spec sheet — a one or two-page document from the manufacturer listing every performance number, dimension, and certification. If you're a facility manager, building owner, or GC trying to compare products, these sheets can be overwhelming. Here's how to read them.

Product Name and Number

Every tile has a name (like "Cortega" or "Ultima") and a product number (like "769" or "1912"). The product number is what matters for ordering. The name is marketing. When you call a distributor, use the number.

Manufacturers often have multiple SKUs under one product name for different sizes and edge profiles. Armstrong Ultima 1912 is a 2×2 tegular. Ultima 1911 is the 2×4 version. Same tile material, different size.

NRC (Noise Reduction Coefficient)

The single most important number for acoustics. NRC measures how much sound the tile absorbs on a scale of 0 to 1.0.

0.50-0.55: Basic. Budget tiles. Fine for storage rooms and back-of-house areas.
0.55-0.70: Mid-range. Good for standard offices, retail, education.
0.70-0.85: High absorption. Open-plan offices, conference rooms, healthcare.
0.85+: Maximum absorption. Performance spaces, recording studios, specialty applications.

For open offices where noise is a problem, don't go below NRC 0.70. For more on this, see our NRC and CAC guide.

CAC (Ceiling Attenuation Class)

Measures how well the tile blocks sound from traveling through the ceiling, over a wall partition, and into the next room. This matters in offices with walls that stop at the ceiling tile (not extending to the deck above).

CAC 25-30: Minimal blocking. Sound travels freely through the ceiling.
CAC 33-37: Standard commercial. Adequate for most offices.
CAC 38-44: High blocking. Good for private offices, conference rooms, HR, legal.

If speech privacy between rooms matters, pay attention to CAC. Armstrong's "Total Acoustics" line delivers both high NRC and high CAC — most tiles make you choose one or the other.

Edge Detail

The spec sheet lists the edge profile. This determines how the tile sits in the grid and what the ceiling looks like from below.

Square / Lay-in: Tile sits flat on the grid. Grid face fully visible. Most economical.
Tegular: Tile has a stepped edge that drops below the grid line. Creates a shadow reveal. Most popular for professional offices.
Reveal: Tile sits recessed, with a gap between tile and grid. Geometric, modern look.
Concealed / Snap-in: Grid hidden. Tiles interlock for a seamless ceiling.

The edge profile also tells you which grid you need. A 15/16" tegular tile goes on 15/16" grid. A 9/16" tegular goes on 9/16" grid. Don't mix them.

Size

Standard sizes: 24"×24" (2×2) and 24"×48" (2×4). The spec sheet lists available sizes. Not every tile comes in both sizes. Some specialty tiles only come in 2×2.

Thickness

Typically 5/8" or 3/4" for mineral fiber tiles. Thicker tiles generally have better NRC (more material to absorb sound) and better sag resistance. Premium tiles tend to be 3/4".

Weight

Listed in lbs per square foot. Standard mineral fiber tiles run 0.8-1.2 lbs/sf. This matters for grid loading calculations, especially in seismic zones like California where the grid has to support not just dead weight but lateral forces.

Fire Rating

Almost every commercial ceiling tile is Class A per ASTM E84 (flame spread ≤25, smoke ≤450). The spec sheet confirms this. If a tile isn't Class A, it's unusual and there's probably a reason — check with the architect.

Some spec sheets also list UL fire resistance ratings for ceiling assemblies (like a 1-hour or 2-hour fire-rated ceiling). This is different from the surface burning rating — it refers to the complete assembly (deck, grid, tile) and its ability to contain fire. See our post on fire-rated ceiling assemblies.

Light Reflectance (LR)

Percentage of light reflected off the tile surface. Higher LR means more light bounces back into the room.

0.78-0.83: Standard. Fine for most spaces.
0.85-0.90+: High reflectance. Can reduce lighting energy costs. Premium tiles like Armstrong Ultima hit 0.90.

Humidity Resistance

Listed as maximum RH (relative humidity) the tile can handle without sagging. Standard tiles are rated for 70% RH. HumiGuard+ and similar treatments push that to 95% RH. If your building has humidity issues or inconsistent HVAC, this number matters.

Recycled Content

Listed as a percentage. Important for LEED credits and green building goals. Most major tiles contain 20-80% recycled content. Armstrong and USG both publish these numbers prominently.

Certifications

Look for:

GREENGUARD Gold: Low chemical emissions. Good for indoor air quality.
Declare label: Full ingredient transparency. Required for some green building programs.
USDA BioPreferred: Contains plant-based content.

Putting It Together

When comparing two tiles, put the spec sheets side by side and compare: NRC, CAC, edge, size, fire rating, LR, humidity resistance. Nine times out of ten, the decision comes down to NRC and CAC for performance, edge profile for aesthetics, and price for budget.

Need help picking the right tile? We compare products all day long. Contact us and we'll recommend options for your space.