ASTM E1725-23

Standard Test Methods for Fire Tests of Fire-Resistive Barrier Systems for Electrical System Components

SIGNIFICANCE AND USE
4.1 These fire-test-response test methods evaluate, under the specified test conditions, the ability of a fire-resistive barrier system to inhibit thermal transmission to the electrical system component within.  
4.2 In these procedures, the specimens are 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 these test methods to predict changes in the fire test response characteristics measured. Therefore, the results are valid only for the fire test exposure conditions described in these procedures.  
4.3 These test methods provide a measurement of the transmission of heat to the electrical system components within the barrier system.  
4.4 These test methods provide qualification of a fireresistive barrier system as one element of an electrical system designed to maintain continuous operation of critical functions and processes for a specific fire resistance rating.  
4.4.1 In addition to the temperature data provided by these test methods, numerous other factors, such as referenced in 1.4 shall be considered in specifying such a system.
SCOPE
1.1 These test methods cover fire-test-response.  
1.2 These fire-test-response test methods provide information on the temperatures recorded on the electrical system component within a fire-resistive barrier system during the period of exposure.  
1.3 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.  
1.4 Potentially important factors and fire characteristics not addressed by these test methods include, but are not limited to:  
1.4.1 The performance of the fire-resistive barrier system constructed with components other than those tested.  
1.4.2 An evaluation of the functionality of the electrical system within the fire-resistive barrier system.  
1.4.3 An evaluation of the ampacity of the electrical system within the fire-resistive barrier system.  
1.4.4 An evaluation of the smoke, toxic gases, corrosivity, or other products of heating.  
1.4.5 A measurement of the flame spread characteristics over the surface of the fire-resistive barrier system.  
1.4.6 An evaluation of through-penetration sealing methods.
Note 1: Refer to Test Method E814 for testing of firestop systems.  
1.4.7 Combustibility of materials in the fire-resistive barrier system or of the electrical system components.  
1.4.8 The need for supports beyond those normally required.  
1.4.9 Environmental conditions in the area of service.  
1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.6 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.  
1.7 Fire testing is inherently hazardous. Adequate safeguards for personnel and property shall be employed in conducting these tests.  
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.

General Information

• Status: Published
• Publication Date: 30-Sep-2023
• ICS: 13.220.40 - Ignitability and burning behaviour of materials and products
• ICS: 29.020 - Electrical engineering in general
• Technical Committee: E05 - Fire Standards
• Drafting Committee: E05.11 - Fire Resistance

Relations

• Replaces: ASTM E1725-19 - Standard Test Methods for Fire Tests of Fire-Resistive Barrier Systems for Electrical System Components
• Effective Date: 01-Oct-2023
• Referred By: ASTM E2749-23 - Standard Practice for Measuring the Uniformity of Furnace Exposure on Test Specimens
• Effective Date: 01-Oct-2023

Overview

ASTM E1725-23 is the standard test method published by ASTM International for evaluating the fire resistance of fire-resistive barrier systems used to protect electrical system components. This standard plays a crucial role in ensuring that essential electrical infrastructure maintains its integrity and operational functionality during and after exposure to fire events. The test methods outlined in ASTM E1725-23 assess the ability of these barrier systems to inhibit heat transmission to the enclosed electrical components, thus supporting continuous operation of critical functions. Applicable across a variety of industries, this standard provides a consistent methodology for determining fire resistance ratings of protective barriers for electrical cables, trays, conduits, and related assemblies.

Key Topics

• Fire-Test-Response: Procedures evaluate how well fire-resistive barrier systems prevent thermal transmission to electrical components under defined laboratory fire exposure conditions.
• Measurement Approach: Focuses on temperature monitoring on the protected electrical system components to determine system performance during fire events.
• Scope Limitations:
  • Does not independently evaluate fire hazard or risk under real-world fire scenarios.
  • Factors such as smoke, toxic gas production, flame spread, electrical ampacity, and functionality are not fully covered.
• Applicability: Results are valid only for the specified test exposure conditions; they do not provide full predictive capability for other scenarios.
• Specimen Construction: Test assemblies must represent real-world installations, including proper supports, sealing, and spacing.
• Fire Resistance Ratings: Defined as the maximum time before component temperatures rise beyond stated limits (e.g., an average increase over 250°F (139°C)).
• Safety Guidelines: Fire testing is inherently hazardous, requiring comprehensive safety procedures for personnel and property.
• Units of Measurement: The standard recognizes inch-pound units as official, with SI units as informational references.

Applications

ASTM E1725-23 is widely adopted across sectors that require reliable fire protection of critical electrical systems, including:

• Power Generation and Distribution: Protecting cable trays, conduits, and cabinets in power plants (including nuclear facilities), substations, and control rooms.
• Industrial Facilities: Ensuring factory and process plant electrical systems continue operating during fires, protecting personnel and assets.
• Commercial Buildings: Supporting the integrity of essential electrical wiring infrastructure in office buildings, hospitals, and data centers.
• Infrastructure Projects: Used in tunnels, transportation hubs, and other public works where fire-safe operation of electrical systems is mission-critical.
• Compliance and Certification: Fire-resistive barrier systems tested under ASTM E1725-23 meet regulatory and insurance requirements for fire safety.

Related Standards

To provide comprehensive coverage and interoperability, ASTM E1725-23 references and aligns with the following standards:

• ASTM E119 - Test Methods for Fire Tests of Building Construction and Materials: Provides guidance on time-temperature curves and related fire test parameters.
• ASTM E814 - Test Method for Fire Tests of Penetration Firestop Systems: Referenced for evaluating through-penetration sealing methods.
• ASTM E1529 - Test Methods for Determining Effects of Large Hydrocarbon Pool Fires on Structural Members and Assemblies: Supplies additional fire exposure criteria.

Keywords: fire-resistive barrier systems, electrical system components, fire testing, fire resistance rating, cable tray protection, conduit fire protection, fire-test-response, ASTM E1725-23, thermal transmission, junction box fire safety, industrial fire safety, barrier system qualification.

Standards Content (Sample)

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.
Designation: E1725 − 23 An American National Standard
Standard Test Methods for
Fire Tests of Fire-Resistive Barrier Systems for Electrical
System Components
This standard is issued under the fixed designation E1725; 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* conversions to SI units that are provided for information only
and are not considered standard.
1.1 These test methods cover fire-test-response.
1.6 This standard does not purport to address all of the
1.2 These fire-test-response test methods provide informa-
safety concerns, if any, associated with its use. It is the
tion on the temperatures recorded on the electrical system
responsibility of the user of this standard to establish appro-
component within a fire-resistive barrier system during the
priate safety, health, and environmental practices and deter-
period of exposure.
mine the applicability of regulatory limitations prior to use.
1.3 This standard is used to measure and describe the
1.7 Fire testing is inherently hazardous. Adequate safe-
response of materials, products, or assemblies to heat and
guards for personnel and property shall be employed in
flame under controlled conditions, but does not by itself
conducting these tests.
incorporate all factors required for fire hazard or fire risk
1.8 This international standard was developed in accor-
assessment of the materials, products, or assemblies under
dance with internationally recognized principles on standard-
actual fire conditions.
ization established in the Decision on Principles for the
1.4 Potentially important factors and fire characteristics not
Development of International Standards, Guides and Recom-
addressed by these test methods include, but are not limited to:
mendations issued by the World Trade Organization Technical
1.4.1 The performance of the fire-resistive barrier system Barriers to Trade (TBT) Committee.
constructed with components other than those tested.
1.4.2 An evaluation of the functionality of the electrical 2. Referenced Documents
system within the fire-resistive barrier system. 2
2.1 ASTM Standards:
1.4.3 An evaluation of the ampacity of the electrical system
E119 Test Methods for Fire Tests of Building Construction
within the fire-resistive barrier system.
and Materials
1.4.4 An evaluation of the smoke, toxic gases, corrosivity,
E814 Test Method for Fire Tests of Penetration Firestop
or other products of heating.
Systems
1.4.5 A measurement of the flame spread characteristics
E1529 Test Methods for Determining Effects of Large Hy-
over the surface of the fire-resistive barrier system.
drocarbon Pool Fires on Structural Members and Assem-
1.4.6 An evaluation of through-penetration sealing methods.
blies
NOTE 1—Refer to Test Method E814 for testing of firestop systems.
3. Terminology
1.4.7 Combustibility of materials in the fire-resistive barrier
3.1 Definitions:
system or of the electrical system components.
3.1.1 air drop—lengths of open run conductors or cables
1.4.8 The need for supports beyond those normally re-
supported only at each end.
quired.
1.4.9 Environmental conditions in the area of service.
3.1.2 electrical system components—cable trays, conduits
and other raceways, open run cables and conductors, cables,
1.5 The values stated in inch-pound units are to be regarded
conductors, cabinets, and other components, as defined or used
as standard. The values given in parentheses are mathematical
in the National Electrical Code, and air drops as defined in
3.1.1.
These test methods are under the jurisdiction of ASTM Committee E05 on Fire
Standards and are the direct responsibility of Subcommittee E05.11 on Fire
Resistance. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Oct. 1, 2023. Published October 2023. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1995. Last previous edition approved in 2019 as E1725 – 19. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/E1725-23. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1725 − 23
3.1.3 fire-resistive barrier system—a specific construction of from 300 s to 400 s. The exposed length of the pyrometer tube
devices, materials, or coatings installed around, or applied to, and thermocouple in the furnace chamber shall be not less than
the electrical system components. 12 in. (305 mm).
5.3.2 Test Methods E1529:
3.1.4 specimen—a construction consisting of electrical sys-
5.3.2.1 Measure the temperature of the gases adjacent to and
tem components and a fire-resistive barrier system.
impinging on the test specimens using factory manufactured
3.1.5 test assembly—horizontal or vertical construction on
0.25 in. (6 mm) outside diameter (OD), Inconel-sheathed, Type
which test specimens are to be mounted together with associ-
K, chromel-alumel thermocouples. The time constant, in air, of
ated instrumentation.
the thermocouple assemblies shall be less than 60 s. Use
standard calibration thermocouples with an accuracy of
4. Significance and Use 60.75 %. A minimum length of 20 diameters (125 mm) of the
sheathed junction end of the thermocouple shall be mounted
4.1 These fire-test-response test methods evaluate, under the
parallel to the surface of the test specimen.
specified test conditions, the ability of a fire-resistive barrier
5.4 Furnace Thermocouple Locations—Position the furnace
system to inhibit thermal transmission to the electrical system
control thermocouples before the start of the fire exposure test.
component within.
It shall be permitted to move the thermocouple to avoid
4.2 In these procedures, the specimens are subjected to one
touching the specimen as a result of its deflection during the
or more specific sets of laboratory test conditions. If different
test.
test conditions are substituted or the end-use conditions are
5.4.1 Place the junction of each thermocouple 12 in. 6 1 in.
changed, it is not always possible by or from these test methods
(305 mm 6 25 mm) from the surface of horizontal construc-
to predict changes in the fire test response characteristics
tions or 12 in. 6 1 in. from the surface of specimens mounted
measured. Therefore, the results are valid only for the fire test
in horizontal constructions.
exposure conditions described in these procedures.
5.4.2 Place the junction of each thermocouple 6 in. 6 1 in.
(152 mm 6 25 mm) from the surface of vertical constructions
4.3 These test methods provide a measurement of the
or 6 in. 6 1 in. from the surface of specimens mounted in
transmission of heat to the electrical system components within
vertical constructions.
the barrier system.
5.4.3 Use a minimum of three thermocouples.
4.4 These test methods provide qualification of a fireresis-
5.4.3.1 For specimens mounted in horizontal constructions,
2 2
tive barrier system as one element of an electrical system
there shall be no less than five thermocouples per 100 ft (9 m )
designed to maintain continuous operation of critical functions
of exposed area. Calculate the exposed area to be the sum of
and processes for a specific fire resistance rating.
the exterior surface area of the fire-resistive barrier system plus
4.4.1 In addition to the temperature data provided by these the area of the horizontal construction exposed to the furnace
test methods, numerous other factors, such as referenced in 1.4 fire.
shall be considered in specifying such a system. 5.4.3.2 For specimens mounted in vertical constructions,
there shall be no less than nine thermocouples per 100 ft
(9 m ) of exposed area. Calculate the exposed area to be the
5. Control of Fire Test
sum of the exterior surface area of the fire resistive barrier
5.1 Fire Test Exposure Conditions:
system plus the area of the vertical construction exposed to the
5.1.1 Time-Temperature Curve—Maintain the fire environ-
furnace fire.
ment within the furnace in accordance with the standard
5.5 Furnace Control:
time-temperature curve shown in Test Method E119 or the
5.5.1 Test Method E119 Time-Temperature Curve:
rapid temperature rise curve shown in Test Method E1529.
5.5.1.1 The control of the furnace control shall be such that
5.2 Furnace Temperatures:
the area under the time-temperature curve, obtained by aver-
aging the results from the furnace thermocouple readings, is
5.2.1 The temperature fixed by the curve shall be the
within 10 % of the corresponding area under the standard
average temperature obtained from readings of thermocouples
time-temperature curve for fire tests of 1 h or less duration,
distributed within the test furnace. Disperse the thermocouples
within 7.5 % for those over 1 h and not more than 2 h, and
as symmetrically as possible within the furnace to measure the
within 5 % for tests exceeding 2 h in duration.
temperature near all exterior surfaces of the specimen. Do not
place the thermocouples at locations where temperature read-
ings would be effected by drafts within the furnace.
A typical thermocouple meeting these time-constant requirements may be
5.2.2 Measure and report the temperatures at intervals not
fabricated by fusion-welding the twisted ends of No. 18 B&S gage, 0.040 in. (1.02
exceeding 1 min.
mm), chromel-alumel wires, mounting the leads in porcelain insulators and inserting
the assembly so the thermocouple bead is 0.50 in. (13 mm) from the sealed end of
5.3 Furnace Thermocouples:
a standard weight, nominal ⁄2 in. iron, steel, or Inconel (a registered trademark of
5.3.1 Test Method E119: INCO Alloys Inc., 3800 Riverside Dr., P.O. Box 1958, Huntingdon, WV 25720)
pipe. The time constant for this and for several other thermocouple assemblies was
5.3.1.1 Enclose the thermocouples in sealed protection
measured in 1976. The time constant may also be calculated from knowledge of its
tubes of such materials and dimensions that the time constant
physical and thermal properties. See Research Report RR:E05-1001, available from
of the protected thermocouple assembly lies within the range ASTM Headquarters.
E1725 − 23
5.5.2 Test Method E1529 Time-Temperature Curve: the heated area of the furnace such that the entire exposed
5.5.2.1 The control of the furnace shall be such that the area vertical dimension lies below the neutral pressure plane.
under the time-temperature curve of the average of the gas
5.6.3.2 Locate the pressure measuring probe tips within
temperature measurements is within 10 % of the corresponding
6 in. of the vertical centerline of the test specimen. Separate the
curve developed in the furnace calibration for tests of 30 min
probes by a minimum of one third of the longest inside
or less duration, within 7.5 % of those over 30 min and not
dimension of the test furnace. Alternatively, separate the two
more than 1 h, and within 5 % for tests exceeding 1 h.
probes by a minimum of 12 in. (305 mm) vertical distance
within the furnace, and the location of the neutral plane
5.6 Furnace Pressure—The furnace pressure control de-
calculated as a function of their vertical separation and their
scribed in the sections that follow pertain to tests performed
pressure difference.
using either of the two time-temperature curves.
5.6.4 Vertical Test Assembly:
5.6.1 Measure the pressure differential between the labora-
5.6.4.1 Position specimens within the heated area of the
tory ambient air and the interior of the fire test furnace with a
furnace such that at least one half of the vertical dimension lies
minimum of two pressure probes.
above the neutral pressure plane.
5.6.2 The pressure measuring probe tips shall be either of
5.6.4.2 Separate at least two probes by a vertical distance
the “T” type as shown in Fig. 1, or of the “tube” type as shown
in Fig. 2, and shall be manufactured from stainless steel or within the furnace equal to one half the furnace height or 12 in.
(305 mm), whichever is greatest, and calculate the location of
other suitable material.
5.6.3 Horizontal Test Assembly: the neutral plane as a function of their vertical separation and
their pressure difference.
5.6.3.1 Maintain the differential pressure at neutral at a
point not less than 12 in. (305 mm) below the exposed surface 5.6.5 Measure the pressure by means of a manometer or
of the test assembly. No specimen shall be positioned within pressure transducer. The manometer or transducer shall be
FIG. 1 Furnace Pressure Probe 1
E1725 − 23
FIG. 2 Furnace Pressure Probe 2
capable of reading 0.01 in. water (2.5 Pa), with a measurement 6.2.2 Vertical Assemblies:
precision of 0.005 in. water (1.25 Pa).
6.2.2.1 The exposed vertical height of the test specimen
shall not be less than 60 in. (1524 mm).
6. Specimen Construction
6.2.2.2 The exposed horizontal depth between the vertical
6.1 Construct the horizontal or vertical test assembly of
test assembly and the closest surface of the vertical specimen
materials that offer adequate support for the test specimen
shall not be less than 36 in. (914 mm).
during the fire exposure. The designs and installation of the
6.2.3 Airdrop:
fire-resistive barrier systems and electrical system components
6.2.3.1 To evaluate an airdrop in the vertical configuration
shall be representative of actual end use.
only, the exposed vertical length of the test specimen shall not
6.2 Electrical System Components—Test components at
be less than 24 in. (610 mm) (see Fig. 5).
their full size and linear dimensions for which evaluation is
6.2.3.2 To evaluate an airdrop in the horizontal configura-
desired. If the full-size component’s linear dimensions are
tion only, the exposed horizontal length shall not be less than
greater than those specified under each component type in this
24 in. (610 mm).
section, utilize the dimensions shown, unless data is required
6.2.3.3 To evaluate an airdrop for both vertical and horizon-
for a unique design. Cable trays, conduits, and other raceways
tal with a bend, the exposed vertical length shall not be less
are tested without conductors, unless the test is for a unique
than 24 in. (610 mm) and the exposed horizontal length shall
design. Suggested arrangements are shown in Figs. 3 and 4.
not be less than 24 in. (see Fig. 6).
6.2.1 Cable Trays, Raceways, and Open-Run Cables:
6.2.4 Cabinets (Junction and Pull Boxes):
6.2.1.1 Horizontal Assemblies:
6.2.4.1 Test these items at their full dimensions for which
6.2.1.2 The exposed vertical depth of the test specimen shall
evaluation is desired.
not be less than 36 in. (914 mm).
6.2.1.3 The exposed horizontal length between the inside 6.3 Provide assembly with through-penetration fire stops
surfaces of the vertical sections shall not be less than 60 in. and internal specimen seals. Construct these using materials
(1524 mm). and techniques capable of withstanding the fire exposure test.
E1725 − 23
FIG. 3 Standard Electrical Component Assembly
FIG. 4 Unique Electrical Component Assembly
Internal seals in cable trays and raceways shall be required in 6.4 Locate the periphery of the specimen not closer than
order to eliminate convective cooling of the test specimen. 12 in. (305 mm) from the inside furnace edge and maintain a
E1725 − 23
FIG. 5 Vertical Air Drop Assembly
minimum separation distance between adjacent test specimens 7.1.3 Cabinets (Junction or Pull Boxes)—Place thermo-
of 12 in. unless it is documented that closer placement does not couples on the outside surface. Place thermocouples as fol-
affect the results. lows:
7.1.3.1 Each face shall have a minimum of one
7. Specimen Instrumentation thermocouple, located at its geometric center,
7.1.3.2 One thermocouple for every square foot of surface
7.1 Temperature Measurement—Make temperature mea-
area per face, and
surements by thermocouples placed at the following locations
7.1.3.3 At a point within 1 in. (25 mm) of each penetration
(see Fig. 7):
connector/interface.
7.1.1 Cable Trays—Place thermocouples on the outside
7.1.4 Airdrops and Open Runs—Place thermocouples on a
longitudinal center surface of each side rail and on a bare No.
single bare No. 8 AWG stranded copper wire. Place airdrop
8 AWG stranded copper wire placed outside the horizontal
thermocouples as follows:
center of the tray and attached to the bottom of the tray. Place
7.1.4.1 One inch (25 mm) from the junction of the airdrop
cable tray thermocouples as follows:
and the fire-exposed side of the penetration seal or cable tray,
7.1.1.1 One inch (25 mm) from the junction of the tray and
and
the fire exposed side of the penetration seal,
7.1.4.2 At points 6 in. 6 ⁄2 in. (152 mm 6 13 mm) along
7.1.1.2 Immediately adjacent to any support members, and
1 the length of the copper wire.
7.1.1.3 At points 6 in. 6 ⁄2 in. (152 mm 6 13 mm) along
the rail/copper wire.
7.2 Consider each configuration of thermocouples a “set” of
7.1.2 Conduits and Other Raceways—Place thermocouples
thermocouples; that is, each side rail equals one set, one bare
on the outside surface of the conduit closest to the furnace floor
No. 8 AWG equals one set.
or furnace wall, or both. Place conduit thermocouples as
7.3 Temperature measurements are allowed to be made at
follows:
locations in addition to those described in 7.1 for the purpose
7.1.2.1 One inch (25 mm) from the junction of the conduit
of providing additional information on the performance of the
and the fire-e
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E1725 − 19 E1725 − 23 An American National Standard
Standard Test Methods for
Fire Tests of Fire-Resistive Barrier Systems for Electrical
System Components
This standard is issued under the fixed designation E1725; 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 These test methods cover fire-test-response.
1.2 These fire-test-response test methods provide information on the temperatures recorded on the electrical system component
within a fire-resistive barrier system during the period of exposure.
1.3 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.
1.4 Potentially important factors and fire characteristics not addressed by these test methods include, but are not limited to:
1.4.1 The performance of the fire-resistive barrier system constructed with components other than those tested.
1.4.2 An evaluation of the functionality of the electrical system within the fire-resistive barrier system.
1.4.3 An evaluation of the ampacity of the electrical system within the fire-resistive barrier system.
1.4.4 An evaluation of the smoke, toxic gases, corrosivity, or other products of heating.
1.4.5 A measurement of the flame spread characteristics over the surface of the fire-resistive barrier system.
1.4.6 An evaluation of through-penetration sealing methods.
NOTE 1—Refer to Test Method E814 for testing of firestop systems.
1.4.7 Combustibility of materials in the fire-resistive barrier system or of the electrical system components.
1.4.8 The need for supports beyond those normally required.
1.4.9 Environmental conditions in the area of service.
These test methods are under the jurisdiction of ASTM Committee E05 on Fire Standards and are the direct responsibility of Subcommittee E05.11 on Fire Resistance.
Current edition approved June 1, 2019Oct. 1, 2023. Published July 2019October 2023. Originally approved in 1995. Last previous edition approved in 20142019 as
ɛ1
E1725E1725 – 19.–14 . DOI: 10.1520/E1725-19.10.1520/E1725-23.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1725 − 23
1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.6 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.
1.7 Fire testing is inherently hazardous. Adequate safeguards for personnel and property shall be employed in conducting these
tests.
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:
E119 Test Methods for Fire Tests of Building Construction and Materials
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
3. Terminology
3.1 Definitions:
3.1.1 air drop—lengths of open run conductors or cables supported only at each end.
3.1.2 electrical system components—cable trays, conduits and other raceways, open run cables and conductors, cables, conductors,
cabinets, and other components, as defined or used in the National Electrical Code, and air drops as defined in 3.1.1.
3.1.3 fire-resistive barrier system—a specific construction of devices, materials, or coatings installed around, or applied to, the
electrical system components.
3.1.4 specimen—a construction consisting of electrical system components and a fire-resistive barrier system.
3.1.5 test assembly—horizontal or vertical construction on which test specimens are to be mounted together with associated
instrumentation.
4. Significance and Use
4.1 These fire-test-response test methods evaluate, under the specified test conditions, the ability of a fire-resistive barrier system
to inhibit thermal transmission to the electrical system component within.
4.2 In these procedures, the specimens are 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 these test methods to predict
changes in the fire test response characteristics measured. Therefore, the results are valid only for the fire test exposure conditions
described in these procedures.
4.3 These test methods provide a measurement of the transmission of heat to the electrical system components within the barrier
system.
4.4 These test methods provide qualification of a fireresistive barrier system as one element of an electrical system designed to
maintain continuous operation of critical functions and processes for a specific fire resistance rating.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
E1725 − 23
4.4.1 In addition to the temperature data provided by these test methods, numerous other factors, such as referenced in 1.4 shall
be considered in specifying such a system.
5. Control of Fire Test
5.1 Fire Test Exposure Conditions:
5.1.1 Time-Temperature Curve—Maintain the fire environment within the furnace in accordance with the standard time-
temperature curve shown in Test Method E119 or the rapid temperature rise curve shown in Test Method E1529.
5.2 Furnace Temperatures:
5.2.1 The temperature fixed by the curve shall be the average temperature obtained from readings of thermocouples distributed
within the test furnace. Disperse the thermocouples as symmetrically as possible within the furnace to measure the temperature
near all exterior surfaces of the specimen. Do not place the thermocouples at locations where temperature readings would be
effected by drafts within the furnace.
5.2.2 Measure and report the temperatures at intervals not exceeding 1 min.
5.3 Furnace Thermocouples:
5.3.1 Test Method E119:
5.3.1.1 Enclose the thermocouples in sealed protection tubes of such materials and dimensions that the time constant of the
protected thermocouple assembly lies within the range from 300300 s to 400 ss. . The exposed length of the pyrometer tube and
thermocouple in the furnace chamber shall be not less than 12 in. (305 mm).
5.3.2 Test Methods E1529:
5.3.2.1 Measure the temperature of the gases adjacent to and impinging on the test specimens using factory manufactured 0.25-in.
(6-mm)0.25 in. (6 mm) outside diameter (OD), Inconel-sheathed, Type K, chromel-alumel thermocouples. The time constant, in
air, of the thermocouple assemblies shall be less than 60 s. 60 s. Use standard calibration thermocouples with an accuracy of
60.75 %. A minimum length of 20 diameters (125 mm) (125 mm) of the sheathed junction end of the thermocouple shall be
mounted parallel to the surface of the test specimen.
5.4 Furnace Thermocouple Locations—Position the furnace control thermocouples before the start of the fire exposure test. It shall
be permitted to move the thermocouple to avoid touching the specimen as a result of its deflection during the test.
5.4.1 Place the junction of each thermocouple 12 6 1 in. (305 6 25 mm) 12 in. 6 1 in. (305 mm 6 25 mm) from the surface of
horizontal constructions or 12 6 1 in. 12 in. 6 1 in. from the surface of specimens mounted in horizontal constructions.
5.4.2 Place the junction of each thermocouple 6 6 1 in. (152 6 25 mm) 6 in. 6 1 in. (152 mm 6 25 mm) from the surface of
vertical constructions or 6 6 1 in. 6 in. 6 1 in. from the surface of specimens mounted in vertical constructions.
5.4.3 Use a minimum of three thermocouples.
2 2
5.4.3.1 For specimens mounted in horizontal constructions, there shall be no less than five thermocouples per 100 ft (9 m ) of
exposed area. Calculate the exposed area to be the sum of the exterior surface area of the fire-resistive barrier system plus the area
of the horizontal construction exposed to the furnace fire.
5.4.3.2 For specimens mounted in vertical constructions, there shall be no less than nine thermocouples per 100 ft100 ft (9
A typical thermocouple meeting these time-constant requirements may be fabricated by fusion-welding the twisted ends of No. 18 B&S gage, 0.040 in. (1.02 mm),
chromel-alumel wires, mounting the leads in porcelain insulators and inserting the assembly so the thermocouple bead is 0.50 in. (13 mm) from the sealed end of a standard
weight, nominal ⁄2 in. iron, steel, or Inconel (a registered trademark of INCO Alloys Inc., 3800 Riverside Dr., P.O. Box 1958, Huntingdon, WV 25720) pipe. The time constant
for this and for several other thermocouple assemblies was measured in 1976. The time constant may also be calculated from knowledge of its physical and thermal properties.
See Research Report RR:E05-1001, available from ASTM Headquarters.
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m(9 m ) of exposed area. Calculate the exposed area to be the sum of the exterior surface area of the fire resistive barrier system
plus the area of the vertical construction exposed to the furnace fire.
5.5 Furnace Control:
5.5.1 Test Method E119 Time-Temperature Curve:
5.5.1.1 The control of the furnace control shall be such that the area under the time-temperature curve, obtained by averaging the
results from the furnace thermocouple readings, is within 10 % of the corresponding area under the standard time-temperature
curve for fire tests of 1 h or less duration, within 7.5 % for those over 1 h and not more than 2 h, and within 5 % for tests exceeding
2 h in duration.
5.5.2 Test Method E1529 Time-Temperature Curve:
5.5.2.1 The control of the furnace shall be such that the area under the time-temperature curve of the average of the gas
temperature measurements is within 10 % of the corresponding curve developed in the furnace calibration for tests of 30 min or
less duration, within 7.5 % of those over 30 min and not more than 1 h, and within 5 % for tests exceeding 1 h.
5.5.3 If the indicated rating for the protection system is 60 min or more, it shall be increased or decreased by the following
correction to compensate for significant variation of the measured furnace temperature from the standard time-temperature curve.
The correction is to be expressed by the following formula:
A 2 A
s
C 5 2I (1)
3 A 1L
~ !
s
where:
C = correction in the same units at I,
I = indicated fire resistance period,
A = area under the curve of the average furnace temperature for the first three fourths of the indicated period,
A = area under the standard time-temperature curve for the first three fourths of the indicated period, and
s
L = lag correction in the same units as A and A 54°F·h or 30°C·h (3240°F·min or 1800°C·min). L is only applicable to
s
thermocouples described in 5.3.1 and becomes zero for thermocouples described in 5.3.2.
5.6 Furnace Pressure—The furnace pressure control described in the sections that follow pertain to tests performed using either
of the two time-temperature curves.
5.6.1 Measure the pressure differential between the laboratory ambient air and the interior of the fire test furnace with a minimum
of two pressure probes.
5.6.2 The pressure measuring probe tips shall be either of the “T” type as shown in Fig. 1, or of the “tube” type as shown in Fig.
2, and shall be manufactured from stainless steel or other suitable material.
5.6.3 Horizontal Test Assembly:
5.6.3.1 Maintain the differential pressure at neutral at a point not less than 12 in. (305 mm) below the exposed surface of the test
assembly. No specimen shall be positioned within the heated area of the furnace such that the entire exposed vertical dimension
lies below the neutral pressure plane.
5.6.3.2 Locate the pressure measuring probe tips within 6 in. 6 in. of the vertical centerline of the test specimen. Separate the
probes by a minimum of one third of the longest inside dimension of the test furnace. Alternatively, separate the two probes by
a minimum of 12 in. (305 mm) vertical distance within the furnace, and the location of the neutral plane calculated as a function
of their vertical separation and their pressure difference.
5.6.4 Vertical Test Assembly:
5.6.4.1 Position specimens within the heated area of the furnace such that at least one half of the vertical dimension lies above
the neutral pressure plane.
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FIG. 1 Furnace Pressure Probe 1
5.6.4.2 Separate at least two probes by a vertical distance within the furnace equal to one half the furnace height or 12 in. (305
mm), whichever is greatest, and calculate the location of the neutral plane as a function of their vertical separation and their
pressure difference.
5.6.5 Measure the pressure by means of a manometer or pressure transducer. The manometer or transducer shall be capable of
reading 0.01 in. water (2.5 Pa), with a measurement precision of 0.005 in. water (1.25 Pa).
6. Specimen Construction
6.1 Construct the horizontal or vertical test assembly of materials that offer adequate support for the test specimen during the fire
exposure. The designs and installation of the fire-resistive barrier systems and electrical system components shall be representative
of actual end use.
6.2 Electrical System Components—Test components at their full size and linear dimensions for which evaluation is desired. If the
full-size component’s linear dimensions are greater than those specified under each component type in this section, utilize the
dimensions shown, unless data is required for a unique design. Cable trays, conduits, and other raceways are tested without
conductors, unless the test is for a unique design. Suggested arrangements are shown in Figs. 3 and 4.
6.2.1 Cable Trays, Raceways, and Open-Run Cables:
6.2.1.1 Horizontal Assemblies:
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FIG. 2 Furnace Pressure Probe 2
6.2.1.2 The exposed vertical depth of the test specimen shall not be less than 36 in. (914 mm).
6.2.1.3 The exposed horizontal length between the inside surfaces of the vertical sections shall not be less than 60 in. (1524 mm).
6.2.2 Vertical Assemblies:
6.2.2.1 The exposed vertical height of the test specimen shall not be less than 60 in. (1524 mm).
6.2.2.2 The exposed horizontal depth between the vertical test assembly and the closest surface of the vertical specimen shall not
be less than 36 in. (914 mm).
6.2.3 Airdrop:
6.2.3.1 To evaluate an airdrop in the vertical configuration only, the exposed vertical length of the test specimen shall not be less
than 24 in. (610 mm) (see Fig. 5).
6.2.3.2 To evaluate an airdrop in the horizontal configuration only, the exposed horizontal length shall not be less than 24 in. (610
mm).
6.2.3.3 To evaluate an airdrop for both vertical and horizontal with a bend, the exposed vertical length shall not be less than 24
in. (610 mm) and the exposed horizontal length shall not be less than 24 in. (see Fig. 6).
6.2.4 Cabinets (Junction and Pull Boxes):
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FIG. 3 Standard Electrical Component Assembly
FIG. 4 Unique Electrical Component Assembly
6.2.4.1 Test these items at their full dimensions for which evaluation is desired.
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FIG. 5 Vertical Air Drop Assembly
6.3 Provide assembly with through-penetration fire stops and internal specimen seals. Construct these using materials and
techniques capable of withstanding the fire exposure test. Internal seals in cable trays and raceways shall be required in order to
eliminate convective cooling of the test specimen.
6.4 Locate the periphery of the specimen not closer than 12 in. (305 mm) 12 in. (305 mm) from the inside furnace edge and
maintain a minimum separation distance between adjacent test specimens of 12 in. 12 in. unless it is documented that closer
placement does not affect the results.
7. Specimen Instrumentation
7.1 Temperature Measurement—Make temperature measurements by thermocouples placed at the following locations (see Fig. 7):
7.1.1 Cable Trays—Place thermocouples on the outside longitudinal center surface of each side rail and on a bare No. 8 AWG
stranded copper wire placed outside the horizontal center of the tray and attached to the bottom of the tray. Place cable tray
thermocouples as follows:
7.1.1.1 One inch (25 mm) from the junction of the tray and the fire exposed side of the penetration seal,
7.1.1.2 Immediately adjacent to any support members, and
7.1.1.3 At points 66 in. 6 ⁄2 in. (152 6 13 mm) in. (152 mm 6 13 mm) along the rail/copper wire.
7.1.2 Conduits and Other Raceways—Place thermocouples on the outside surface of the conduit closest to the furnace floor or
furnace wall, or both. Place conduit thermocouples as follows:
7.1.2.1 One inch (25 mm) from the junction of the conduit and the fire-exposed side of the penetration seal,
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FIG. 6 Vertical and Horizontal Air Drop Assembly
7.1.2.2 Immediately adjacent to any support members, and
7.1.2.3 At points 66 in. 6 ⁄2 in. (152 6 13 mm) in. (152 mm 6 13 mm) along the length of the conduit.
7.1.3 Cabinets (Junction or Pull Boxes)—Place thermocouples on the outside surface. Place thermocouples as follows:
7.1.3.1 Each face shall have a minimum of one thermocouple, located at its geometric center,
7.1.3.2 One thermocouple for every square foot of surface area per face, and
7.1.3.3 At a point within 1 in. (25 mm) of each penetration connector/interface.
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