ATAS offers numerous hole size and placement combinations for perforated metal panels. While standard rounds holes are the most economical, custom shapes and variations are available at an additional cost and with design limitations. 
Six standard patterns available: 
A13 - 
1/8" holes, 3/16" staggered centers, 40% open area
A15 - 1/8" holes, 1/4" staggered centers, 23% open area
A23 - 1/4" holes, 1/2" staggered centers, 23% open area
A24 - 3/8" holes, 1/2" staggered centers, 52% open area
A19 - 3/16" holes, 5/16" staggered centers, 33% open area
A25 - 3/8" holes, 9/16" staggered centers, 40% open area
A perforation pattern is specified as follows:
Hole Size x Center to Center Distance x Orientation and the Open Area Produced 

ATAS Standard Pattern “A23” is:  .25” x .5” OC Staggered, 23% OA
The holes are ¼” in diameter
Spaced ½” apart center-center diagonally at a 60 degree angle, which produces 23% open area, or metal loss – 23% of the metal is removed.
Perforated metal panels have several basic applications. The type or requirements of the perforation may dictate or determine the perforation pattern.  
Ventilation: Provides airflow
Acoustical: Panels are used for sound dampening
Architectural: Passive shading/sunscreen, decorative application, signage, panel infills or ornamental contrast.
Perforated metal panels offer unlimited flexibility and extensive design variations.
Insulated Metal Panels brochure


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NCCU Brite, Durham, NC

Perforated Belvedere Short Rib Panel (BWK360), Silversmith (both sides)

Waltrip Raceworld USA, Lake Norman, NC

Perforated Corra-Lok (MFC160), Silversmith

United Cerebal Palsy Center Office, Pittsburgh, PA

Perforated Belvedere Span Wall (BWS240), Ascot White

Libby Mill, Richmond, VA

Perforated Belvedere (BWR360), Patina Green

75 Tresser, Stamford, CT

Perforated Belvedere Short Rib, Ascot White; Metafor, Clear Anodized, Versa-Lok, Silversmith; Versa-Seam, Slate Grey

Rocketship Fuerza Community Prep

Perforated Belvedere Penum Wall, Teal

West Mec NE Campus, Phoenix, AZ

Perforated Corrugated Metal Panel (BWC374), Perforated Opaline (OPF060), Custom Colors

Bixby Redhill, Irvine, CA

Perforated Belvedere 6" Short Rib (BWK360), Clear Anodized

Bixby Redhill, Irvine, CA

Perforated Belvedere 6" Short Rib (BWK360), Clear Anodized

North Hills Parking Deck, Raleigh, NC

Perforated Metafor, Dove Grey

Fromagex, Quebec, Canada

Corrugated Panel (BWC374), Ascot White

Ascent Uptown, Charlotte, NC

Perforated Corrugated Panel, Rocky Grey, Regal Blue, & Slate Blue

CaroMont Regional Medical Center, Gastonia, NC

Perforated Corrugated Panel, Dove Grey

Pacific Box & Crate, Charleston, SC

Perforated Belvedere 7.2" Rib in Clear Satin Anodized

Wiseburn High School, El Segundo, CA

Perforated Belvedere Grand R, Custom Blue

Get Air, Pomona, CA

Perforated Belvedere 7.2" Rib, Classic Bronze