of Standard Steel Doors
This document shall provide guidelines for the specifying,
installing, and adjusting of standard steel doors
and frames in applications where sound control is a
1.2.1 Sound Transmission Class
A single number rating that indicates the sound transmission
loss over a defined range of frequencies of a
door assembly between adjacent closed rooms, abbreviated
STC. Higher values equate to better sound
1.2.2 Outdoor-Indoor Transmission Class
A single number rating used to compare door assemblies
when subjected to exterior sounds, such
as ground or air transportation noise, is abbreviated
1.2.3 Sound transmission loss –TL
The reduction in sound level at specific frequency levels
when sound passes through a door assembly.
The number of cycles per second of a sound wave,
measured in units of Hertz and abbreviated Hz.#
1.2.5 Decibel – dB
A unit used to express the intensity of a sound wave,
equal to 20 times the common logarithm of the ratio of
the pressure produced by the sound wave to a reference
pressure, usually 0.0002 microbar.
1.2.6 Sound Control Door Assembly
An assembly consisting of a door, frame, hardware,
threshold, and gasketing, capable of reducing the
transmission of sound.
2.1 Test Specimen
Unless otherwise specified, the test specimen shall
be a nominal 36" (914 mm) wide, by 84" (2133 mm)
high for single doors and 72" (1,829 mm wide, by 84"
(2133 mm) high for pairs of doors. All doors shall be 1
3/4" (44 mm) in thickness. All doors shall be fully operable.
A detailed description of the test assembly shall
be included in the test report.
Ratings derived from non-operable assemblies shall
only be used for experimental purposes and are not
part of this document.
2.2 Test Method
The door assemblies shall be tested in accordance with ASTM E 90. The STC and OITC ratings shall be calculated in accordance with ASTM E 413 and E 1332, respectively. The latest editions of the standards shall be used in determining the STC and OITC ratings. Testing shall be performed at laboratories that are accredited under the National Voluntary Laboratory Accreditation Program (NVLAP)
2.3 Test Results and Report
The test report shall be prepared by the test laboratory and shall contain the information identified in Section 13 of ASTM E 90 or Section 8 of ASTM E 1425.
3 Design Criteria
3.1 Performance Considerations
The proper function of acoustical doors relies on a
combination of factors that are under the control of
various firms, trades, specifiers, suppliers, and designers.
Without the cooperation of all concerned, the
installed opening may not function as intended. Proper
seal installation and adjustment are critical to the performance of the opening. The installation guidelines
shall be provided by the manufacturer.
Consideration must be given to correctly specifying
the door capability for the project condition. Some
doors, although rated higher in overall STC or OITC
ratings may not perform as well as lower rated doors
at certain frequencies. The test reports should be reviewed
to establish the best TL values at the frequencies
under consideration for a given project.
Room design should create a full enclosure equal to
or greater than the door’s TL capabilities. For example,
walls that do not run full height to a similar rated
overhead structure will allow sound leakage through
ceilings, louvers, pipe chases, access doors, etc.
Carpeting, although considered a good source of
sound absorption, should not be used underneath
acoustical doors. Door bottom gaskets must compress
against a solid object to affect a proper seal.
Carpeting by its nature does not provide that type of
Walls, in addition to their STC rating, should be designed
to support the additional weight of acoustical
doors. A wall that moves or flexes each time the door
is operated cannot ensure that the gasket alignment
will be maintained.
The manufacturer’s literature should be consulted to
determine the weight of acoustical doors; especially,
those that have higher acoustical ratings.
3.2 Field Testing
Results obtained from field-testing may vary from
those obtained under laboratory conditions. Atmospheric
conditions, room volumes, wall type and design,
sound diffusion, test equipment, etc. may affect
the results obtained when testing in the field.
3.3 Hardware Considerations
Hardware should be specified giving special consideration
to the fact that it will be used on acoustical
doors. Any type of hardware that may be the source
of sound leakage should be avoided. Since all acoustical
doors depend on a tight perimeter seal, some
types of hardware will become difficult to operate due
to the compression required to seal the opening.