ASTM E2749-23a

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Designation: E2749 − 23 E2749 − 23a An American National Standard
Standard Practice for
Measuring the Uniformity of Furnace Exposure on Test
Specimens
This standard is issued under the fixed designation E2749; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This standard provides general principles for measuring the uniformity of the furnace exposure on specimens tested in
accordance with Test Methods E119, E814, E1529, E1725, E1966, and E2336.
1.2 This practice specifies the materials and the construction requirements for a standardized test specimen used to provide a
mounting surface for the instrumentation that measures furnace exposure.
1.3 The instrumentation records temperatures, pressure differentials, and oxygen content near the exposed surface of the test
specimen.
1.4 The values stated in SI units are to be regarded as the standard. The units given in parentheses are for information only.
1.5 This standard is used to measure and describe the response of materials, products, or assemblies to heat and flame under
controlled conditions, but does not by itself incorporate all factors required for fire hazard or fire risk assessment of the materials,
products, or assemblies under actual fire conditions.
1.6 Fire testing is inherently hazardous. Adequate safeguards for personnel and property shall be employed in conducting these
tests.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.8 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
C1396/C1396M Specification for Gypsum Board
E119 Test Methods for Fire Tests of Building Construction and Materials
This practice is under the jurisdiction of ASTM Committee E05 on Fire Standards and is the direct responsibility of Subcommittee E05.11 on Fire Resistance.
Current edition approved Oct. 1, 2023Dec. 1, 2023. Published October 2023January 2024. Originally approved in 2010. Last previous edition approved in 20192023 as
E2749 – 15a (2019).E2749 – 23. DOI:10.1520/E2749-23.DOI:10.1520/E2749-23A.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
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E2749 − 23a
E176 Terminology of Fire Standards
E814 Test Method for Fire Tests of Penetration Firestop Systems
E1529 Test Methods for Determining Effects of Large Hydrocarbon Pool Fires on Structural Members and Assemblies
E1725 Test Methods for Fire Tests of Fire-Resistive Barrier Systems for Electrical System Components
E1966 Test Method for Fire-Resistive Joint Systems
E2336 Test Methods for Fire Resistive Grease Duct Enclosure Systems
2.2 ISO Standard:
ISO 834-2 Fire resistance tests – Elements of building construction – Part 2: Guide on measuring uniformity of furnace exposure
on test samples
3. Terminology
3.1 Definitions—For definitions of terms used in this practice, refer to Terminology E176.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 effective area of the furnace opening, n—furnace opening within the boundaries of the monitoring instrumentation.
4. Summary of Practice
4.1 This practice consists of preparing a standardized test specimen to represent test specimens described in Test Methods E119,
E814, E1529, E1725, E1966, and E2336. The standardized test specimen provides a low cost, easily constructed supporting
construction for the mounting of instrumentation that measures the exposure imposed by the furnace onto test specimens.
4.2 The standardized test specimen consists of two layers of 15.9 mm ( ⁄8 in.) thick Type X gypsum board on the surface facing
the furnace chamber attached to steel channels and a single layer of structural panels (plywood or oriented strand board) attached
to the steel channels on the surface away from the furnace chamber. The gypsum board provides a fire-resistive surface for the
mounting of the instrumentation. The structural panels provide stability for the steel support channels.
4.3 Instrumentation to measure the thermal impact due to exposure to the furnace upon the standardized test specimen is installed
at various locations on the exposed surface of the standardized test specimen. Probes used to gather air samples within the furnace
chamber are also installed.
4.4 The standardized test specimen is exposed to the time-temperature curve specified in referenced ASTM fire test standards for
a time period of 45 min during which time data are recorded by the instrumentation mounted on the standardized test specimen.
4.5 The data provide a record of the conditions and uniformity of the furnace exposure upon standardized test specimens. The area
bounded by the instrumentation installed on the standardized test specimen is designated as the effective area of the furnace
opening.
5. Significance and Use
5.1 This practice describes a procedure to gather data intended to measure the uniformity of exposure conditions upon test
specimens for the fire test methods described in Test Methods E119, E814, E1529, E1725, E1966, and E2336. The collected data
from furnaces are intended to form a basis for performance requirements for the furnaces described in the referenced standards.
5.2 This practice does not include requirements for furnace performance.
5.3 In this procedure, the standardized test specimen is subjected to one or more specific sets of laboratory test conditions. If
different test conditions are substituted or the end-use conditions are changed, it is not always possible by or from this procedure
to predict changes in the fire-test-response characteristics measured. Therefore, the results are valid only for the fire-test-exposure
conditions described in this procedure.
Available from International Organization for Standardization (ISO), ISO Central Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland,
https://www.iso.org.
E2749 − 23a
Dimensions in millimetres.
FIG. 1 Horizontal Standardized Test Specimen, Location of Joists and Track Channels
5.4 The attention of all persons connected with the conduct of this practice is drawn to the fact that fire testing is hazardous and
that there is a possibility that harmful smoke and gases are developed during the test. There is also a possibility that mechanical
and operational hazards develop during the construction of the test specimen and the disposal of the test residues. An assessment
of all potential hazards and risks to health shall be made and safety precautions shall be identified and provided. Written safety
instructions shall be issued. Appropriate training shall be provided to relevant personnel. Laboratory personnel shall ensure that
they follow written safety instructions at all times.
6. Apparatus
6.1 The furnace(s) and restraining frame(s) used to conduct tests in accordance with Test Methods E119, E814, E1529, E1725,
E1966, and E2336 shall be used.
6.2 Standardized Test Specimen:
6.2.1 Materials—The materials used to construct the standardized test specimen shall consist of the following: gypsum board,
structural panels, cold-formed steel supports and fasteners.
6.2.1.1 The gypsum board shall be minimum 15.9 mm ( ⁄8 in.) thick complying with the requirements of Type X as defined in
Specification C1396/C1396M.
6.2.1.2 The structural panels shall be minimum 18 mm (nominal ⁄4 in.) thick. Typical materials include plywood and oriented
strand boards.
6.2.1.3 The cold-formed steel joists for horizontal specimens shall be fabricated from minimum 1.4 mm thick (0.055 in.) steel. The
cold formed steel joists shall be “C” shaped having a minimum depth of 240 mm (9 ⁄2 in.), a minimum flange width of 40 mm
5 1
(1 ⁄8 in.) and a minimum lip length of 12 mm ( ⁄2 in.).
6.2.1.4 The cold-formed steel wall studs for vertical specimens shall be fabricated from minimum 0.9 mm thick (0.035 in.) steel.
The cold-formed steel wall studs shall be “C” shaped having a minimum depth of 90 mm (3 ⁄2 in.), a minimum flange width of
1 1
30 mm (1 ⁄4 in.) and a minimum folded back return flange legs of 5 mm ( ⁄4 in.).
E2749 − 23a
Dimensions in millimetres.
FIG. 2 Horizontal Standardized Test Specimen, Location of Inner Layer of Gypsum Board and Structural Panels
6.2.1.5 The cold-formed steel track channels for the horizontal and vertical specimens shall be “C” shaped having a depth
compatible with the joists or wall studs being used.
6.2.1.6 Steel fasteners used to attach the gypsum board to the studs and joists shall be designed for the attachment of gypsum board
1 3
to steel supports. Typical screws have a thread diameter of 5 mm ( ⁄4 in.) and a head diameter of 8 mm ( ⁄8 in.). The steel fasteners
used to attach the inner layer shall have a minimum length of 25 mm (1 in.). The steel fasteners used to attach the exposed layer
shall have a minimum length of 40 mm (1 ⁄8 in.).
6.2.1.7 Fasteners used to attach the structural panels to the studs and joists shall be designed for the attachment of the panels to
steel supports.
6.2.2 Construction Method—Horizontal Standardized Test Specimen.
6.2.2.1 The construction details with respect to the location of the joists, track channels, gypsum board and the structural panels
3 3
are shown in Figs. 1-3. The construction details assume a furnace opening of 4.2 m by 4.2 m (13 ft 9 ⁄8 in. by 13 ft 9 ⁄8 in.).
Modifications to dimensions are necessary for other furnace openings.
7 3
6.2.2.2 The steel joists shall be spaced 300 mm to 450 mm (11 ⁄8 in. to 17 ⁄4 in.) on center. The joists are inserted into the track
channels. The use of steel clip angles are permissible to facilitate the attachment of the joists to the track channels.
6.2.2.3 The inner layer of gypsum board shall be attached to the joists with the steel screws spaced a maximum of 200 mm
7 3 5
(7 ⁄8 in.) on center along each joist. A distance of 10 mm to 15 mm ( ⁄8 in. to ⁄8 in.) shall be provided between the screws and the
edges of the gypsum board.
NOTE 1—The inner layer, or base layer, of gypsum board is in contact with the joists.
6.2.2.4 The exposed layer of gypsum board shall be attached to the joists with steel screws spaced a maximum 200 mm (7 ⁄8 in.)
on center along each joist and shall be spaced 100 mm (4 in.) from the screws used to attach the inner layer. A distance of 10 mm
3 5
to 15 mm ( ⁄8 in. to ⁄8 in.) shall be provided between the screws and the edges of the gypsum board.
NOTE 2—The exposed layer, or outside layer, of gypsum board is in contact with the inner layer of gypsum board.
6.2.2.5 The structural panels shall be attached to the joists with steel screws spaced a maximum of 150 mm (5 ⁄8 in.) on center
E2749 − 23a
Dimensions in millimetres.
FIG. 3 Horizontal Standardized Test Specimen, Location of Outer Layer of Gypsum Board
3 5
along each joist. A distance of 10 mm to 15 mm ( ⁄8 in. to ⁄8 in.) shall be provided between the screws and the edges of the
structural panels. Holes are permissible in the structural panels to facilitate the installation of the instrumentation.
6.2.3 Construction Method—Vertical Standardized Test Specimen:
6.2.3.1 The construction details with respect to the location of the wall studs, track channels, gypsum board and the structural
panels are shown in Figs. 4-6. The construction details assume a furnace opening of 3.1 m by 3.1 m (10 ft 2 in. by 10 ft 2 in.).
Modifications to dimensions are necessary for other furnace openings.
7 3
6.2.3.2 The wall studs shall be spaced 300 mm to 450 mm (11 ⁄8 in. to 17 ⁄4 in.) on center. The studs are inserted into track
channels. The use of steel clip angles are permissible to facilitate the attachment of the studs to the track channels.
6.2.3.3 The inner layer of gypsum board shall be attached to the studs with the steel screws spaced a maximum of 200 mm (7 ⁄8
3 5
in.) on center along each stud. A distance of 10 mm to 15 mm ( ⁄8 in. to ⁄8 in.) shall be provided between the screws and the edges
of the gypsum board.
NOTE 3—The inner layer, or base layer, of gypsum board is in contact with the studs.
6.2.3.4 The exposed layer of gypsum board shall be attached to the studs with steel screws spaced a maximum 200 mm (7 ⁄8 in.)
on center along each stud and shall be spaced 100 mm (4 in.) from the screws used to attach the inner layer. A distance of 10 mm
3 5
to 15 mm ( ⁄8 in. to ⁄8 in.) shall be provided between the screws and the edges of the gypsum board.
NOTE 4—The exposed layer, or outside layer, of gypsum board is in contact with the inner layer of gypsum board.
6.2.3.5 Th
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