Acrylic vs Glass
Acrylic vs Glass
Acrylic is often used where safety and ease of handling are of concern. It has 10x-20x greater impact strength than conventional plate glass and similar impact strength compared to tempered glass. If it does break, an acrylic sheet will crack or fracture into large pieces with edges that are much less sharp than those of broken glass. In addition to its excellent impact strength, an acrylic sheet of the same size and thickness is half the weight of glass, resulting in cheaper shipping costs. It also provides excellent thermal conductivity over glass and is available with chemical and scratch resistance.
Impact and Weight
|Material||Falling ball impact strength (ft-lbs)||Weight (lbs/ft2)|
|0.250" thick plate glass||1.0||2.9|
|0.250" thick tempered glass||15.5-29.1||2.9|
|0.250" acrylic sheet||18.1||1.5|
Acrylic also feels warm to the touch, not cold like glass, because it is a better heat insulator. Compared to glass it has a lower coefficient of thermal conductivity. Acrylic is 20% more efficient than uncoated glass at reducing temperature transfer, aiding in temperature regulation, and lowering heating costs.
Typical values for the Coefficient of Thermal Conductivity
Acrylic: 1.3 BTU/(hr-ft2)(F/inch)
Glass: 5.3 BTU/(hr-ft2)(F/inch)
Mechanical strength and stiffness
Acrylic has lower tensile strength and stiffness than glass. When used in glazing, the required thickness will usually be 1.5-2.5 times greater than that required for plate glass to withstand the same wind loads. When used for shelving, the required thickness to support the same weight will be at least 2.5 times greater than that required for plate glass; however, acrylic will offer much greater impact strength. See Roehm America LLC's shelving calculator for assistance.
Expansion and contraction allowances
Acrylic expands and contracts more than glass due to temperature and humidity changes. Its coefficient of thermal expansion is about eight times greater than that of glass. Proper allowances must be made to permit expansion and contraction.
Scratch and Chemical Resistance
The surface of acrylic is not as hard nor as chemically resistant as glass. Therefore, it is more prone to scratching, abrasion and many glass cleaners cannot be used to clean acrylic sheet. If resistance to scratching, abrasion and chemicals are important, then specify ACRYLITE® Optical abrasion resistant (MR) sheet. This revolutionary acrylic sheet has a "glass-like" coating on one or both surfaces that resists scratching. A comparison to glass, ACRYLITE® Optical abrasion resistant (MR) sheet. and uncoated acrylic is shown below.
Squareness and Thickness Tolerances
Strict squareness and thickness tolerances ensure precision when it comes to finished parts. Extruded acrylic has tighter tolerances than glass panels. View our tolerance allowances here: Extruded (FF) squareness tolerances; Extruded (FF) thickness tolerance; Cast thickness tolerances
Typical Values for Taber Abrasion Testing (% haze after 100 cycles)
|ACRYLITE® Optical abrasion resistant (MR) acrylic sheet||1.34%|
|Uncoated Acrylic Sheet||26.88%|