Gives the definitions, classification and general requirements for electrical insulating materials suitable for application as coatings for loaded printed wire boards (conformal coatings). This standard excludes requirements for compatibility between such coatings and printed wire boards, this characteristic being evaluated in individual applications. Surface modifiers are not classified as conformal coatings. They only provide a thin film that does not cure and has low mar resistance. They are excluded from this standard. Materials which conform to this standard meet established levels of performance. However, the selection of a material by a user for a specific application should be based on the actual requirements necessary for adequate performance in that application and not based on this standard alone. This edition includes the following significant technical changes from the previous edition: a) a Class 3 material for aerospace applications has been included, b) a new resin type (oligomeric blend material) has been added.