Acrylic for electric sign faces

ACRYLITE® acrylic sheet has been the material of choice for electric sign faces for almost 50 years. It has enjoyed this position due to its:

• Outstanding weatherability - better than any other common transparent plastic material
• Almost unlimited color availability
• Ease of fabrication
• Lower cost than polycarbonate

From the UL standpoint, ACRYLITE® sheet is suitable for electric sign faces as long as it does not function as an “enclosure”. An “enclosure” in this case is defined as a barrier that separates open voltage sources from the outside world and NOT as something that surrounds or confines. If a plastic material is considered to be part of an enclosure then it must have a UL94 V flammability rating. No acrylic material has such a rating but users need to be aware of the fact that through the proper use of other insulating systems around all live electrical parts (such as pk-connectors), the sign face does not need to function as an “enclosure” and does not need a UL94 V rating.

Unfortunately, many users of the UL Sign Accessories Manual (SAM) have misunderstood the UL position on the use of acrylic sheet. Many believe that acrylic sheet cannot be used in signs since it is not mentioned in the manual. Furthermore, the definition of the word “enclosure” as used in UL48 is often misunderstood. As already mentioned, an enclosure in this case is defined as a barrier that separates open voltage sources from the outside world and NOT as something that surrounds or confines.

ACRYLITE® sheet is a recognized polymeric component under QMFZ2 as a UL94 HB material. It is suitable for outdoor use with respect to exposure to ultraviolet light, water exposure and immersion (per UL746C). Therefore, ACRYLITE® sheet is suitable as a sign face or a water shield.