Overview
ASTM E1042-22: Standard Classification for Acoustically Absorptive Materials Applied by Trowel or Spray establishes a classification system for materials directly applied to surfaces for the purpose of increasing sound absorption. These acoustically absorptive materials are essential for controlling reverberation and echoes in various built environments, improving their acoustic quality. The standard provides uniform criteria for classifying these materials based on types, sound absorption performance, fire properties, and dust propensity.
Key Topics
- Material Application: The standard addresses materials specifically applied to surfaces by either trowel or spray, covering a variety of construction and renovation contexts.
- Material Types: Three main classes are defined:
- Type I: Cementitious materials, requiring mixing with water for application.
- Type II: Fibrous materials, either with a pre-mixed binder or supplied for mixing with a liquid binder during application.
- Type III: Cellular plastic materials, designed for mixing and immediate application onto building surfaces.
- Sound Absorption Classification: Materials are graded according to their Noise Reduction Coefficient (NRC) or Sound Absorption Average (SAA), with minimum acceptable values ranging from NRC 0.40 to 0.95 or higher.
- Flame Spread Index: The standard categorizes materials by fire performance:
- Class (a): Flame spread index must not exceed 25 and smoke developed rating not more than 50.
- Class (b): Flame spread index not exceeding 75.
- Class (c): Flame spread index not exceeding 200.
- Dust Propensity: Classified into:
- Category A: Dust release not exceeding 0.27 g/m².
- Category B: Dust release exceeding 0.27 g/m².
Applications
ASTM E1042-22 is widely applicable in sectors that require effective sound absorption in interior spaces. Typical uses include:
- Commercial Buildings: Offices, conference rooms, and public foyers to reduce echo and enhance speech intelligibility.
- Educational Facilities: Classrooms, lecture halls, and libraries for improved acoustic comfort and learning environments.
- Healthcare Environments: Hospitals, clinics, and treatment rooms where noise control is essential for patient well-being.
- Entertainment Venues: Theaters, concert halls, and auditoria requiring control over reverberation and echoes.
- Industrial Settings: Manufacturing and processing areas where reducing noise can improve safety and productivity.
Because the classification addresses fire and dust properties as well as sound absorption performance, selecting materials according to ASTM E1042-22 can also help meet building and fire codes, as well as occupational health requirements.
Related Standards
This classification references several important ASTM standards for testing and terminology:
- ASTM C423: Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberation Room Method
- ASTM C634: Terminology Relating to Building and Environmental Acoustics
- ASTM E84: Test Method for Surface Burning Characteristics of Building Materials
- ASTM E795: Practices for Mounting Test Specimens During Sound Absorption Tests
- ASTM E859: Test Method for Air Erosion of Sprayed Fire-Resistive Materials
Compliance with ASTM E1042-22 enables consistent evaluation and specification of acoustically absorptive, trowel- or spray-applied materials, supporting better project outcomes and regulatory adherence in building acoustics.
Keywords: acoustically absorptive materials, sound absorption, spray-applied materials, trowel-applied materials, noise reduction coefficient, flame spread index, dust propensity, ASTM E1042-22