ASTM F3664-24

Standard Practice for Blast Testing

SIGNIFICANCE AND USE
4.1 This practice shall be followed for blast testing with an aim toward maximizing the consistency and repeatability between blast tests and test facilities. Specific requirements include test configuration, instrumentation, test result processing, data reductions, facility requirements, clearing effects, and fixturing or reaction structure design.  
4.2 In this practice, inconsistencies in blast testing methodology are reduced and blast testing reporting (interpretation and documentation of blast results) is standardized. This improved consistency of practice will facilitate direct comparison of results, testing repeatability, and identification of trends.  
4.3 This practice shall apply to blast simulator testing where applicable, including all aspects of the specification except those that are specific to open air explosive testing.  
4.4 Uses—This practice in total is required for open air blast tests and applicable sections are required for blast simulator tests. Any deviation or exception to the practice should be addressed as early in the planning stage as possible and shall require written approval by the AHJ.
SCOPE
1.1 Purpose—The primary purpose of this practice is to define good commercial and customary practice for conducting blast tests of physical security products, related devices, and systems. The goal is to harmonize results between test facilities and maximize the consistency and repeatability of the results obtained from these blast tests. This practice shall be used for blast simulator testing, where applicable.  
1.2 Objectives—Objectives guiding the development of this practice are:  
1.2.1 Formalize standard practices for conducting blast tests.  
1.2.2 Facilitate high-quality, standardized results processing and reporting of test results.  
1.2.3 Use as a starting point for a best practice standard that will grow into an industry standard both domestically and internationally.  
1.2.4 It is anticipated that this practice will evolve over time as requirements and facility capabilities change.  
1.2.5 This practice should not be considered the limit of requirements for proper completion of a given test program. There may be additional requirements depending on the application and the threat.  
1.3 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.4 Omissions—The omission of any specific explosive, instrumentation type, material type, or test configuration does not necessarily preclude its use in accordance with this practice, as long as all applicable provisions are satisfied.  
1.5 The following is a table of contents for this practice:  
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 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: 31-Dec-2023
• Technical Committee: F12 - Security Systems and Equipment
• Drafting Committee: F12.10 - Systems Products and Services

Overview

ASTM F3664-24: Standard Practice for Blast Testing establishes comprehensive guidelines for conducting blast tests on physical security products, devices, and systems. Developed by ASTM International, this standard is designed to harmonize results across test facilities by providing detailed procedures for test configuration, instrumentation, data processing, reporting, and facility requirements. By reducing methodological inconsistencies, this standard practice facilitates reliable comparison of blast test data, enhances repeatability, and supports the identification of trends in blast resistance performance. ASTM F3664-24 is applicable to both open-air and blast simulator testing, ensuring best practices are implemented industry-wide.

Key Topics

• Test Configuration: Guidance on how to set up blast tests, including test article mounting, reaction structure design, standoff distance, and charge placement, ensures consistency and realism in conducted tests.
• Instrumentation: Requirements and recommendations for pressure transducers, displacement measurements, force, strain, acceleration, temperature sensors, high-speed photography, and video capture for comprehensive data collection.
• Data Processing and Reduction: Standardized approaches for collecting, processing, and reporting raw and processed data, including metrics such as peak pressure, impulse calculation, and the use of redundant gauges to improve reliability.
• Test Facility Requirements: Direction for test site topography, blast pad construction, camera vantage points, minimizing signal noise, and safe handling and storage of explosives.
• Clearing Effects and Reaction Structure: Specifications for controlling edge effects (clearing effect) and maintaining adequate reaction structure stiffness and mass to prevent influence on test results.
• Test Planning and Reporting: Documentation, approval, and deviation processes to ensure clear communication between test performers and the authority having jurisdiction (AHJ).

Applications

ASTM F3664-24 is a critical resource for organizations involved in the testing and evaluation of physical security barriers, glazing systems, blast-resistant components, and related protective technologies. The standard has practical value for:

• Product Development and Certification: Manufacturers use this practice to validate the blast resistance of new materials or security products and to support certification with harmonized, high-quality test results.
• Comparative Testing: Facilities and agencies conducting comparative or repeated blast tests can achieve consistency and reduce variability, enabling meaningful product benchmarking.
• Regulatory Compliance: Public and private stakeholders rely on this standard to demonstrate adherence to national and international regulations for blast safety in infrastructure and critical asset protection.
• Best Practices Adoption: Provides a foundation for developing and refining industry-wide best practices as test methods and facility capabilities evolve.
• Blast Simulator Testing: Applies to test programs using blast simulators, with specific configurations and data collection methods to match open-air test requirements where feasible.

Related Standards

• ASTM F1642: Test Method for Glazing and Glazing Systems Subject to Airblast Loadings - frequently referenced for pressure transducer requirements.
• General Practices: Aligns with globally recognized principles on standardization, including those established by the World Trade Organization (WTO) Technical Barriers to Trade (TBT) Committee.
• Other Security and Blast Testing Standards: Complements ASTM standards addressing components of physical security, such as reaction structure design, instrumentation validation, and explosive material handling.

By following ASTM F3664-24, organizations ensure robust, repeatable, and internationally recognized approaches to blast testing, supporting product safety, innovation, and regulatory compliance in critical security applications.

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: F3664 − 24
Standard Practice for
Blast Testing
This standard is issued under the fixed designation F3664; 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 1.5 The following is a table of contents for this practice:
TABLE 1 Section Numbers and Titles
1.1 Purpose—The primary purpose of this practice is to
Section Number Title
define good commercial and customary practice for conducting
1 Scope
blast tests of physical security products, related devices, and
1.1 Purpose
1.2 Objectives
systems. The goal is to harmonize results between test facilities
1.3 Units
and maximize the consistency and repeatability of the results
1.4 Omissions
obtained from these blast tests. This practice shall be used for 1.5 Table of contents
2 Referenced Documents
blast simulator testing, where applicable.
2.1 ASTM Standards
3 Terminology
1.2 Objectives—Objectives guiding the development of this
3.2 Definitions
practice are:
3.3 Acronyms and Symbols
4 Significance and Use
1.2.1 Formalize standard practices for conducting blast
5 Test Facility Requirements
tests.
5.1 Topography
5.2 Camera Vantage Points
1.2.2 Facilitate high-quality, standardized results processing
5.3 Blast Pad for Open Airblast Testing
and reporting of test results.
5.3.1 Concrete Pads
5.3.2 Steel Plate
1.2.3 Use as a starting point for a best practice standard that
5.4 Signal Noise
will grow into an industry standard both domestically and
5.5 Handling of Explosives
internationally. 6 Instrumentation
6.1 Applicable Instrumentation
1.2.4 It is anticipated that this practice will evolve over time
6.2 Pressure Transducers
6.3 Displacement Measurements
as requirements and facility capabilities change.
6.3.1 Optical/Laser Gauges
1.2.5 This practice should not be considered the limit of
6.3.2 Rod Deflection Potentiometers
requirements for proper completion of a given test program. 6.3.3 String Potentiometers
6.3.4 Accelerometers
There may be additional requirements depending on the
6.3.5 Global Movement of Reaction Structure
application and the threat.
6.3.6 Other Displacement Measurements
6.4 Acceleration Measurements
1.3 Units—The values stated in SI units are to be regarded
6.5 Direct Force Measurement
6.5.1 Load Cells
as standard. The values given in parentheses after SI units are
6.6 Strain Measurement
provided for information only and are not considered standard.
6.7 Temperature Measurement
6.8 Photographs
1.4 Omissions—The omission of any specific explosive,
6.9 Video
instrumentation type, material type, or test configuration does 6.10 Witness Panel
6.11 Redundancy and Correlation
not necessarily preclude its use in accordance with this
6.12 Mounting Cameras and Sensors
practice, as long as all applicable provisions are satisfied.
6.13 DAQ
6.14 Calibration and Validation
6.14.1 Calibration
6.14.2 Pre-Test Check of Instrumentation
1 6.14.3 Modifications to Test Plan
This practice is under the jurisdiction of ASTM Committee F12 on Security
7 Reaction Structure
Systems and Equipment and is the direct responsibility of Subcommittee F12.10 on
7.1 Nonresponding Structure
Systems Products and Services.
7.2 Elastic to the Load
Current edition approved Jan. 1, 2024. Published February 2024. DOI: 10.1520/
7.3 Fixturing and Test Article Mounting
F3664-24.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F3664 − 24
TABLE 1 Continued
2. Referenced Documents
Section Number Title
2.1 ASTM Standards:
7.4 Global Movement Mitigation
F1642 Test Method for Glazing and Glazing Systems Sub-
7.5 Face of Reaction Structure
7.6 Reflections
ject to Airblast Loadings
7.7 Enclosed Space Behind Test Article
7.8 Clearing Effects
3. Terminology
7.9 Reaction Structure Construction Specifics
8 Test Plan 3.1 This section provides definitions, descriptions of terms,
8.1 Submission
and a list of acronyms for many of the terms used in this
8.1.1 Test Article(s)
practice. These terms are an integral part of this practice and
8.1.2 Blast Loading
8.1.2.1 Specified Pressure and Impulse are critical to an understanding of this practice and its use.
8.1.2.1(1) Calibration Tests and Validation
3.2 Definitions:
8.1.2.1(2) Pressure Gauge Redundancy
8.1.2.1(3) Targeted Pressure and Impulse
3.2.1 ammonium nitrate, fuel oil, ANFO, n—a mixture of
8.1.2.1(4) Charge Shape and Configuration
technical grade (TG) ammonium nitrate (AN) prills and fuel oil
8.1.2.2 Specified TNT Equivalence
(FO), typically No. 2 diesel fuel; by mass, approximately 94 %
8.1.2.3 Specified Shape and Configuration of Charge
8.1.2.3(1) Cylindrical Shape with TNT Impulse-Equivalence
AN and 6 % FO; a common, stable, and relatively inexpensive
113.4 kg (250 lbm) or Greater
explosive commonly used for blast testing.
8.1.2.3(2) TNT Impulse-Equivalence Less Than 113.4 kg (250 lbm)
3.2.1.1 Discussion—Per 5.5, non-uniformity ANFO such as
8.1.2.4 Explosive Mass
8.1.2.5 Detonation
“clumping” or “caking” of the prills shall be considered as
8.1.3 Instrumentation Plan
defects and shall not be used under this practice.
8.1.4 Reaction Structure
8.1.5 Witness Panel
3.2.2 authority having jurisdiction, AHJ, n—organization,
9 Pre-Test Through Post-Test
office, or individual having the responsibility to see that
9.1 Test Site Visit by the AHJ
customer’s or end user’s requirements are properly addressed.
9.1.1 Observation of Setup
9.1.2 Pre-Test Walkthrough
3.2.2.1 Discussion—The AHJ is the customer’s technical
9.1.3 Post-Test Examination
representative having direct or delegated authority to represent
9.2 As-Tested Article
9.2.1 Fabrication the technical interests of the customer or end user. The AHJ
9.2.2 Installation
works in cooperation with the test director during test planning,
9.2.3 Materials of Construction
test execution, and test reporting.
9.3 Reporting Deviations
9.4 On-Site Documentation by the AHJ
3.2.3 approved, adj—acceptable to the authority having
9.5 On-Site Review of Results
jurisdiction (AHJ).
9.6 Range Safety
10 Data Processing and Reduction
3.2.4 blast, n—synonym for explosion.
10.1 Raw Data
10.2 Processed Data 3.2.5 blast load, n—load applied from a blast wave, which
10.3 Time Scale
is described by the combination of pressure, impulse, and
10.4 Videos
duration.
10.5 Peak Pressure
10.6 Impulse Calculation
3.2.6 blast simulator, n—device or system using a high-
11 Report
energy source to generate a target pressure versus time having
11.1 Report Contents
11.2 References
a positive phase shape, pressure, and impulse that replicates
11.3 Results
airblast pressure loads.
11.4 Event Setup
3.2.6.1 Discussion—A blast simulator may not be capable of
12 Keywords
Annex A1 Airblast Test Plan Checklist
producing an airblast negative phase pressure history.
Table A1.1 Airblast Test Plan Checklist
3.2.7 clearing effect, n—clearing effect or “clearing” is a
Annex A2 Blast Simulator Test Plan Checklist
Table A2.1 Blast Simulator Test Plan Checklist
hydrodynamic phenomenon caused by blast pressure waves
N/A Related Materials
diffracting around the edges of a structure that in turn generates
a relief wave propagating inward from the edges.
1.6 This standard does not purport to address all of the
3.2.7.1 Discussion—The effect of these relief waves is to
safety concerns, if any, associated with its use. It is the
reduce the impulse placed on the structure.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
3.2.8 dynamic response, n—deformation, stress, and other
mine the applicability of regulatory limitations prior to use. behavior of structure or structural element caused by the action
of a time-varying loading while considering inertia, stiffness,
1.7 This international standard was developed in accor-
and, in some cases, damping effects.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Development of International Standards, Guides and Recom-
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
mendations issued by the World Trade Organization Technical
Standards volume information, refer to the standard’s Document Summary page on
Barriers to Trade (TBT) Committee. the ASTM website.
F3664 − 24
3.2.9 equivalent mass of trinitrotoluene (TNT), n—one mea- 3.2.15 generally accepted practice, n—in this practice,
sure of the energy (power) contained in a given amount of a corresponds to means or methods that are commonly known or
specified explosive expressed as the mass of TNT that would generally accepted in the community of blast effects on
result in the same peak pressure or impulse, all other param- structural devices and systems.
eters being equal.
3.2.16 impulse, n—cumulative blast loading over time, cal-
3.2.9.1 Discussion—A number generally ranging between
culated as the area under a pressure-time plot.
0.7 and 1.7. Note that, for some explosives, the equivalent
3.2.17 near range, n—distance at which the explosive is in
mass can differ depending upon whether comparing peak
close proximity to the test article relative to the size of the
pressures or impulses.
explosive, such that the resulting blast loading shall be con-
3.2.10 explosion, n—rapid chemical reaction that produces
sidered to be non-uniformly distributed over the tributary area
noise, heat, and a rapid violent expansion of gases.
of the element being loaded.
3.2.11 explosive, n—material or device capable of causing 3.2.17.1 Discussion—This is commonly accepted to corre-
an explosion under certain conditions, such as heat, shock, spond to a scaled distance, Z, that is less than
m ft
electrostatic discharge, or friction.
1.2 3 .
S D
1⁄3 1⁄3
kg lbm
3.2.12 explosive, adj—relating to, characterized by, or op-
3.2.18 nonresponding, adj—typically used to describe a
erated by explosion.
reaction structure and test frame.
3.2.13 far range, n—distance at which the blast loading
3.2.18.1 Discussion—Nonresponding is a term used to de-
from an explosion can be considered to be uniformly distrib-
scribe a support system wherein the response of the support
uted over the tributary area of the element to be loaded.
structure does not influence the response of the tested article.
3.2.13.1 Discussion—This is commonly accepted to corre-
3.2.19 range, n—distance from the centroid of the explosive
spond to a scaled distance, Z, that is equal to or greater than
to a reference point on the targeted test article unless otherwise
m ft
1.2 3 .
S D
1⁄3 1⁄3
specified by the AHJ; see Fig. 1.
kg lbm
3.2.14 fixturing, n—devices or assemblies that may be used 3.2.20 reaction structure, n—structure used to support the
as interfaces between the test article and the test frame or test article, test frame, and fixturing during the blast event.
reaction structure. 3.2.20.1 Discussion—The reaction structure normally has
3.2.14.1 Discussion—Typically, the fixturing is intended to large mass and stiffness compared with the anticipated loading
provide realistic local support conditions for the test article. and response of the test article. Examples include reinforced
FIG. 1 Range and Standoff
F3664 − 24
concrete boxed-shaped rooms, reinforced concrete culverts, or 3.3.2 ANFO—Ammonium nitrate, fuel oil
containers filled with soil positioned behind the test frames.
3.3.3 DAQ—Data acquisition system (also known as DAS)
Another example may be a test frame mounted to a sled with
3.3.4 R—Range distance from centroid of the explosive to a
the sled held in place by concrete blocks or possibly sandbags.
point on the test article, m (ft)
3.2.21 rigid, adj—used to describe a structural component
3.3.5 t —Duration of positive phase, ms
d
or system that has very high strength and very small deforma-
3.3.6 TNT—Trinitrotoluene
tions or deflections relative to the loading and, accordingly, has
a very small effect on the response of the test article. 3.3.7 U —Shock front velocity, m/ms (ft/ms)
s
3.2.22 scaled distance, Z, n—ratio of the range to the cube 3.3.8 W—Explosive mass as an equivalent quantity of TNT,
kg (lbm)
root of the explosive charge size as an equivalent mass of TNT,
which commonly serves as the basis for determining the blast
R m ft
3.3.9 Z—Scaled distance Z5 ,
1⁄3 1⁄3S 1⁄3D
loading parameters. W kg lbm
3.2.23 standoff, n—the horizontal distance between a refer-
4. Significance and Use
ence plane on the reaction structure to the explosive device’s
4.1 This practice shall be followed for blast testing with an
reference point which shall be the centroid of the explosive
aim toward maximizing the consistency and repeatability
device, unless otherwise defined by the AHJ; see Fig. 1.
between blast tests and test facilities. Specific requirements
3.2.23.1 Discussion—Typically, the standoff is measured to
include test configuration, instrumentation, test result
the center of the charge. As there may be exceptions, it is
processing, data reductions, facility requirements, clearing
important that the standoff be clearly defined in the test plan.
effects, and fixturing or reaction structure design.
Additionally, the position and orientation of each test article
relative to the charge location must be defined.
4.2 In this practice, inconsistencies in blast testing method-
ology are reduced and blast testing reporting (interpretation
3.2.24 test article, n—device or system being tested or
and documentation of blast results) is standardized. This
evaluated.
improved consistency of practice will facilitate direct compari-
3.2.25 test director, n—person representing the test per-
son of results, testing repeatability, and identification of trends.
former or test facility charged with overseeing and directing
4.3 This practice shall apply to blast simulator testing where
test planning, execution, and reporting.
applicable, including all aspects of the specification except
3.2.25.1 Discussion—Test director usually acts as the point
those that are specific to open air explosive testing.
of contact for and works in cooperation with the AHJ.
4.4 Uses—This practice in total is required for open air blast
3.2.26 test facility, n—physical infrastructure, equipment,
tests and applicable sections are required for blast simulator
items, and devices required for the execution of blast tests
tests. Any deviation or exception to the practice should be
including geographical area (blast range), reaction structure,
addressed as early in the planning stage as possible and shall
instrumentation, equipment, tools, power sources, and the like.
require written approval by the AHJ.
3.2.27 test frame, n—typically used as a means of structural
connection between the test article and the reaction structure.
5. Test Facility Requirements
3.2.27.1 Discussion—Test frames are typically constructed
5.1 Topography—The topography immediately adjacent to
from either reinforced concrete or steel assemblies. An ex-
the location of the explosive charge shall be approximately
ample would include a tilt-up reinforced concrete wall placed
level (0.3 m (1.0 ft) rise or fall in 30 m (100 ft)) from the
in front of and rigidly attached to a reaction structure. The test
charge to 25 % of the standoff past the target, within an arc
article may be attached directly to the test frame or there may
encompassing 30° on either side of the reaction structure.
be fixturing included to serve as the interface between the test
Additionally, the area outside the arc shall be clear of any
frame and the test article.
geometrical shapes or items that may inadvertently cause
3.2.28 test performer, n—organization, company, or labora-
reflective or secondary loads on the target. Grade slope and
tory charged with the task of planning and executing the test(s)
reflecting surface behind the charge should be avoided.
and producing the appropriate deliverables related to test(s).
5.2 Camera Vantage Points—The test range shall provide
3.2.28.1 Discussion—The test performer may include per-
sufficient camera vantage points situated to have an unob-
sonnel associated with the test facility.
structed view of all active test (reaction) structures and the
3.2.29 test plan, n—formalized plan, in writing, detailing
charge location. The vantage point(s) shall be sited so as to
the objectives, resources, and process(es) for a specific test to
offer a side view of the hemispherical blast wave striking the
be created and approved before a test occurs, preferably well in
front of the test (reaction) structure, with at least one camera
advance of said test.
for each active test (reaction) structure. The blast test plan may
3.2.30 witness panel, n—panel placed on the protected side dictate other additional camera vantage points to provide other
of a test article that is used to document spall or fragmentation
views.
typically from a test article containing glazing.
5.3 Blast Pad for Open Airblast Testing—Beneath the
3.3 Acronyms and Symbols:
charge location, a blast pad shall be provided to minimize the
3.3.1 AHJ—Authority having jurisdiction influence of the local soil or substrate, or both, on the blast test
F3664 − 24
results. The blast pad shall consist of either a concrete slab, or the gauge with soft materials such as tape or silicone grease
a steel plate, or a combination of both. The blast pad shall may be used to mitigate extraneous noise, if accompanied by
completely bear upon firm in-situ soil or fill material. The top clearly documented evidence that the technique does not
face of the blast pad shall not protrude more than 50 mm (2 in.) significantly affect the pressure wave measurement.
about the surrounding grade. In cases of repeated tests, blast
6.3 Displacement Measurements—Displacement measure-
pads may be reused with careful evaluation of condition after
ments may be obtained by some combination of the following
each test. An exception to requiring blast pads may be
devices or methods. In general, displacement gauge accuracy,
considered in cases in which extremely hard and durable
measured range of movement, and sampling rate should be
substrate is within 300 mm (12 in.) of the surface under the
selected in accordance with the predicted movements of the
charge (shallow bedrock as an example).
tested device. General comments regarding application and
5.3.1 Concrete Pads—Concrete pads shall be normal-
challenges include those in 6.3.1 – 6.3.6.
density concrete and shall have a 28-day compressive strength
6.3.1 Optical/Laser Gauges—Gauges may be used in cases
of no less than 20.7 MPa (3000 psi). Unless directed otherwise
in which debris and dust do not interfere with the signal.
by the AHJ, the concrete pad shall be 2.44 m by 2.44 m by
Excessive movement of the measurement point may also cause
0.23 m (8 ft by 8 ft by 9 in.). Concrete blast pad reinforcement
the signal to be lost mid-test. Flash from explosive detonation
requirements are the responsibility of the test performer but
may also need to be addressed to avoid interference with
shall be a minimum of 9.5 mm rebar spaced at 0.46 m each
proper signal. This is typically accomplished by covering any
face and each way (#3 rebar spaced at 18 in. each face and each
transparent test specimen with an opaque covering.
way).
6.3.2 Rod Deflection Potentiometers—Rod deflection poten-
5.3.2 Steel Plate—Unless directed otherwise by the AHJ,
tiometer gauges (rack and pinion gauges) are typically used in
the steel plate shall be 2.44 m by 2.44 m (8 ft by 8 ft) with a
blast testing, especially where there is considerable dust and
minimum thickness of 25 mm (1 in.). It shall be made in one
debris. Concerns include attachment of the rack to the test
piece (by welding plates together if required) and shall be made
article, column buckling of the rack, and whip of the rack
of mild steel (ductile steel).
during the response. Attachment of the rack to the tested article
5.4 Signal Noise—All powered equipment at the test range, shall not damage the article (particularly in the case of glass)
whether at the cameras, sensors, data acquisition system, or in and shall provide for displacement measurement through
the control bunker, shall be supplied with “clean” filtered inbound and outbound response of the tested article. The rack
power, such that sensor signals are not cluttered with extrane- shall be stiff enough to minimize buckling, lateral whip, or
ous electrical noise. Specifically, it is recommended that the both, that can affect displacement measurement. The mass of
pre-trigger signal noise for sensors be less than 1 % of the the rack should be as small as practicable so as to minimize the
sensor range. A portable option includes generators with possible effect on dynamic response of the tested article.
built-in inverters.
6.3.3 String Potentiometers—String potentiometers (cable-
extension position transducers, also known as yo-yo gauges)
5.5 Handling of Explosives—The test performer shall have
may be used with the caveat that the rate of cable recoil is
written procedures for handling, storing, tracking, and dispos-
limited to a maximum acceleration. Exceeding that accelera-
ing of explosives. Minimum record maintenance should in-
tion can result in measurement error or, in the case of backlash,
clude purchase or shipment: the purchase date, lot number,
total measurement loss. The device is sensitive to small debris
vendor name, and specific technical information regarding
and dust, interfering with the cable movement or introducing
explosive yield. For ANFO, non-uniformity of the product such
extraneous cable movement, or both, thereby affecting the
as “clumping” or “caking” of the prills shall be considered as
displacement measurement.
defects and shall not be used under the scope of this practice.
6.3.4 Accelerometers—Accelerometers (discussed in 6.4)
Unless specified by the manufacturer, the use-by date for
may be used to measure acceleration at key locations with
ANFO is defined as six months from date of purchase and not
displacements calculated via numerical integrations to calcu-
to exceed nine months from the date of manufacture.
late velocity and displacements. The results are typically useful
to “scale” movements and serve as backup to other direct
6. Instrumentation
measurements.
6.1 Applicable Instrumentation—Instrumentation require-
6.3.5 Global Movement of Reaction Structure—The global
ments may vary considerably based on the nature of the test
pre- to post-test movement of the reaction structure shall be
article and the load condition of interest. A given test may
measured relative to a fixed reference. The intent is to
include more than one test article. This section provides
document net movement caused by sliding or shift of the
general guidance for instrumentation sensors, devices, and
structure, resulting from the applied blast load. The measure-
systems as they are applicable to a given test.
ment accuracy shall be within 63 mm (6 ⁄8 in.).
6.2 Pressure Transducers—Pressure transducers shall be 6.3.6 Other Displacement Measurements—Various other
provided in accordance with Test Method F1642. Additionally, techniques may be used such as fiducial markers coupled with
pressure gauges shall be mounted so as to minimize localized high-speed cameras, strain visualization, or other techniques as
clearing effects (for example, mounted flush with the face of approved by the AHJ. A completely different technology
the reaction structure) and structural-response-induced noise involves piezo pin sensors that may be used to measure global
(see also 6.12). Techniques that involve covering the front of displacements, by activating when contact is made with the
F3664 − 24
piezo material in the tip of the pin. In blast application, the pins 6.10 Witness Panel—A witness panel is typically required as
are typically destroyed. In all cases, there shall be well- a means of qualifying and quantifying the amount of fragmen-
documented evidence regarding the efficacy of the method. tation that either passes or is expelled from the tested article.
The specific materials of construction and configuration of the
6.4 Acceleration Measurements—Accelerometers may be
witness panel shall be documented in the test plan and report.
used to characterize response versus time for the tested device
or the reaction structure. Care should be taken regarding
6.11 Redundancy and Correlation—As much as practicable,
general issues such as sensitivity, amplitude range, decay time, a variety of gauges or gauge types shall be used to provide
drift, and mounting (see also 6.12). It is crucial that the linear
redundancy, particularly in cases in which gauges or gauge
frequency range of the accelerometer encompasses the primary signals may be lost during a test. Correlation between, for
response frequencies of the tested device coupled with the
example, accelerations and global movements or strains and
reaction structure. displacements, may be facilitated through careful selection and
placement of gauges.
6.5 Direct Force Measurement—Direct force measurement
may be obtained through strain measurements of key structural
6.12 Mounting Cameras and Sensors—Cameras and sensors
components or implementation of load cells.
shall be supported or attached in such a manner as to minimize
6.5.1 Load Cells—In the case of load cells, the range and
spurious dynamic movements that may clutter or bias images
sensitivity of the load cell shall capture the force response over
or data.
both the inbound and outbound portions of the response.
6.13 DAQ—The DAQ shall consist of a digital recording
Accordingly, any preload applied before the load event shall be
system with a sufficient number of channels to simultaneously
large enough to account for rebound loading. A critical
accommodate the desired number of sensors and transducers.
consideration is the mounting of the load cell (see also 6.12).
The DAQ shall operate at a sufficiently high frequency to
Any residual permanent displacement that may influence the
record the peak positive pressure reliably. The DAQ shall also
accuracy of the load cell force measurement shall be limited to
incorporate filters to preclude alias frequency effects on the
less than 5 % of the gauge displacement corresponding to the
data.
maximum force measured.
6.14 Calibration and Validation:
6.6 Strain Measurement—Strain measurements are most
6.14.1 Calibration—All sensors (pressure, deflection,
reliably obtained using strain gauges mounted directly to
acceleration, and so forth) shall have been calibrated in
structural components (see also 6.12). The selection of the
accordance with the test performer’s standard practice. The
gauges shall include consideration for the material and surface
calibration standard practice shall be submitted with the test
being instrumented as well as the range and linearity of strain
plan for review by the AHJ. The test performer’s standard
values. Particular care shall be taken when strains exceed the
practice and calibration records shall be included as an annex
elastic limit of metals. In all cases, the strain gauges shall be
to the test report.
selected, installed, protected, and instrumented in accordance
6.14.2 Pre-Test Check of Instrumentation—Bench top, or
with generally accepted practice and the gauge manufacturer’s
similar, testing of sensors and instrumentation shall be per-
recommendations. Optical strain measurement and strain visu-
formed before but not to exceed six months before the test
alization techniques may be used when supported by well-
time. The results shall be compared ag
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