This specification covers the requirements for an adhesive which is intended for use in bonding pre-fabricated acoustical materials to the inside walls and ceilings of rooms in buildings. This adhesive is required to maintain a specific tensile adhesion or bond strength for a long period of time under the temperature and moisture conditions likely to be encountered and to maintain sufficient plasticity to allow for movement of parts of the building as it ages. The adhesive shall be of uniform composition, shall be free from all ingredients that will affect its serviceability or have a deleterious effect on the acoustical material, shall not liberate toxic gases or fumes under normal conditions of use and application, nor shall it contain irritating substances. Tests shall be conducted to determine the following adhesive properties: surface adherence; wetting; tensile and adhesion strengths; volume shrinkage; cracking; and plasticity to permit indentation. The specimens shall also be subjected to migration or bleeding and storage tests.

1.1 This specification covers an adhesive for bonding prefabricated acoustical materials to the inside walls and ceilings of rooms in buildings. This adhesive is required to maintain a tensile adhesion (bond strength) of not less than 3.45 × 10⁴ dynes/cm² (½ lb/in.²) for a long period of time under the temperature and moisture conditions likely to be encountered and to maintain sufficient plasticity to allow for movement of parts of the building as it ages.

Note 1—Cleanliness of SurfaceThe surface to which the acoustical material is applied with the adhesive should be clean, sound, and dry. Surface coatings should be removed if their nature indicates an unsatisfactory installation, so that the adhesive can be applied to the base. When the adhesive is to be applied on a painted surface, test tile should be applied for 48 h to determine suitable adherence of the coating by examination. Acoustical adhesives are not intended to be applied to surfaces that are moist and that have an alkaline reaction, or that may later become moist or alkaline. Such surfaces, as concrete or plaster, should be properly dried and aged before applying the adhesive.