Perforated Sheet Patterns

Perforated sheet is a special form of sheet that has a pattern of shapes removed from it. Perforated sheet provides various benefits when compared with regular sheet. The perforation patterns allow for the sheet to be lighter, provide more traction for pedestrians, and let water or other liquids pass through them rather than accumulate. It is important to note that the most common use for perforated sheet is for filtration. When choosing a perforated sheet, material type, thickness, and perforation pattern must be considered. Since there are many patterns to choose from, Metal Supermarkets has provided a guide for selecting a perforated sheet pattern that is best suited for a given application.

Selecting A Perforated Sheet Pattern

Some attributes to consider when selecting a pattern include:

• Open Area
• Hole Size
• Hole Geometry

Open Area

Open area is a measure of how much metal is removed as a percentage of the total metal sheet area prior to perforation. Open area is a major consideration when selecting a pattern on perforated sheet because it has a direct impact on the weight of the metal sheet. Open area also affects the amount and velocity of materials, such as liquids or air that can pass through the perforated sheet. Metal Supermarkets has perforated sheet pattern open area options of up to 79% and as low as 25% to accommodate a range of applications.

Hole Size

Hole size is another consideration that should not be neglected when selecting a pattern for perforated sheet. Most importantly, hole size determines the size of the solid particles that can pass through the perforated sheet. The ability to see through the perforated sheet is also affected by hole size. Up to ½” square and circle perforation patterns are available from Metal Supermarkets for when large hole sizes are required, as are ⅛” circle perforation patterns for applications that require smaller hole sizes.

Hole Geometry

Some hole geometry to consider when selecting a pattern include:

• Round
• Square
• Designer Patterns

Round Holes

Round holes are perhaps the most popular shape for perforated sheet applications. One reason is that they are the easiest shape to perforate a sheet with, resulting in a generally lower cost over other shapes. Also, round holes provide an aesthetically pleasing pattern. Round holes do not present high amounts of geometric stress concentrators like other perforation patterns might.

Round hole perforated sheet is available in staggered and straight alignment. Staggered hole alignment allows for a greater amount of open area per unit of area over straight aligned holes. Staggered alignment also creates an even distribution of holes over the area. This results in a reduced risk of liquid and debris buildup. It also creates an even stress distribution. Straight alignment is useful if the look it provides is desired. It also allows for the use of a variety of hole sizes while still maintaining a relatively lower degree of open area when compared with staggered alignment.

Square Holes

Square-patterned perforated sheet is able to provide a high degree of open area, even more so than round holes because of the way the square perforations can be nested. This is especially useful for applications where high amounts of air flow or liquid drainage are required. Square perforations are somewhat more difficult to make than round holes because of the sharp edges. This usually results in a higher cost for square-patterned perforated sheet. The sharp edges on the square perforations in the sheet also can act as stress concentrators. These stress concentrators can be problematic if the perforated sheet with a square pattern is subjected to high stresses. Squares are available in 0.020”, 0.375” (⅜”), and 0.500 (½”) with several different spacing amounts.

Designer Patterns

Metal Supermarkets also provides a variety of designer patterns for applications that require specific aesthetic appeal. Hexagons provide a high degree of open area while providing an alternative to squares. They are also able to handle stresses somewhat better than squares. Full Clover, Lincane, and Grecian are some of the other designer patterns that Metal Supermarkets provides for its customers.

The table below details the attributes of common perforated sheet patterns offered at Metal Supermarkets:

2/10″ Square (.20″), 1/4″ Centers Straight, 64% Open	3/8″ Square, 1/2″ Centers Straight, 56% Open	1/2″ Square, 11/16″ Centers Straight, 59% Open	Lincane, 44% Open
Tri-Square, 47% Open	Grecian, 35% Open	Airline, 68% Open	Full Clover, 51% Open
Style A-1, 45% Open	1/4″ Hexagonal, 79% Open	1/8″ x 1″ Oblong Side Staggered, 1/4″ Centers, 43% Open	9/64″ Staggered, .141″ Dia. (3.572mm), 3/16″ Centers (4.763mm), 33 holes/sq. in., 51% Open
5/32″ Staggered, .156″ Dia. (3.969mm), 7/32″ Centers (5.556mm), 24 holes/sq. in., 46% Open	5/32″ Staggered, .156″ Dia. (3.969mm), 3/16″ Centers (4.763mm), 33 holes/sq. in., 63% Open	3/16″ Staggered, .1875″ Dia. (4.763mm), 1/4″ Centers (6.350mm), 18.5 holes/sq. in., 51% Open	1/4″ Staggered, .250″ Dia. (6.350mm), 3/8″ Centers (9.525mm), 40% Open
3/8″ Staggered, .375″ Dia. (9.525mm), 1/2″ Centers (12.700mm), 51% Open	1/2″ Staggered, .500″ Dia. (12.700mm), 11/16″ Centers (17.463mm), 18.5 holes/sq. in., 48% Open	No. 2 Straight, .033″ Dia. (0.838mm), 0.056″ Centers (1.397mm), 331 holes/sq. in., 28% Open	No. 3 1/2 Straight, .045″ Dia. (1.143mm), 0.066″ Centers (1.676mm), 230 holes/sq. in., 37% Open
1/16″ Staggered, .0625″ Dia. (1.588mm), 1/8″ Centers (3.175mm), 74 holes/sq. in., 23% Open	3/32″ Staggered, .094″ Dia. (2.361mm), 5/32″ Centers (3.969mm), 47 holes/sq. in., 33% Open	1/8″ Staggered, .125″ Dia. (3.175mm), 3/16″ Centers (4.763mm), 33 holes/sq. in., 40% Open	1/8″ Staggered, .125″ Dia. (3.175mm), 7/32″ Centers (5.556mm)