Attachment 2_ SOP for Blast Testing pub August 2022.pdf

DS/PSP/PSD SOP for Blast Testing 2022

SOP for Blast Testing 2022 UNCLASSIFIED 08/22/2022

Introduction and Executive Summary

1. Scope

2. Referenced Documents

3. Terminology

4. Summary of Practice

5. Significance and Use

6. Health, Safety and Environmental Precautions

7. Facility Requirements

8. Instrumentation

9. Reaction Structure

10. Test Plan

11. Pre-Test Through Post-Test

12. Data Processing and Reduction

13. 13 ANNEX 1. Test Plan Check List APPENDIX 1. Revision Summary APPENDIX 2. Supplemental Definitions, Symbols and Notation Information APPENDIX 3. Background Information

Blast Testing SOP for DS/PSP/PSD Approved for distribution August 22, 2022

ABSTRACT

Contained herein are the standard operating procedures (SOP) for conducting blast and blast simulator testing for the U.S. Department of State which shall promote consistency and repeatability between tests, test facilities, and test performers.

PUBLISHER

U.S. Bureau of Diplomatic Security, Physical Security Program, Physical Security Division (DS/PSP/PSD)

SOP for Blast Testing 2022 UNCLASSIFIED 08/22/2022 Page 1 of 21

BUREAU OF DIPLOMATIC SECURITY

UNITED STATES DEPARTMENTOF STATE

WASHINGTON, D.C.

BLAST TESTING STANDARD PRACTICE FOR DS/PSP/PSD

August 2022

This version supersedes all earlier revisions of this Standard Practice.

Michael J. Mancini

Division Chief, Physical Security Division

Approved:

Gordon B. Morrison Section Chief, Physical Security Research and Development

Craig R. Ackerman Blast Program Manager, Physical Security Research and Development

PHYSICAL SECURITY DIVISION

OFFICE OF PHYSICAL SECURITY PROGRAMS

BUREAU OF DIPLOMATIC SECURITY

U.S. DEPARTMENT OF STATE

WASHINGTON, D.C. 20520

SOP for Blast Testing 2022 UNCLASSIFIED 08/22/2022 Page 1 of 21

Table of Contents Introduction and Executive Summary

1. Scope

2. Terminology

3. Significance and Use

4. Test Facility Requirements

5. Instrumentation

6. Reaction Structure

7. Test Plan

8. Pre-Test Through Post-Test

9. Data Processing and Reduction

10. Test Report ANNEX 1. Airblast Test Plan Checklist 13 ANNEX 2. Blast Simulator Test Plan Checklist APPENDIX 1. Referenced or Relevant Documents APPENDIX 2. Supplemental Definitions, Symbols and Notation APPENDIX 3. Background Information APPENDIX 4. Revision Summary APPENDIX 5. Keywords

SOP for Blast Testing 2022 UNCLASSIFIED 08/22/2022 Page 2 of 21

This standard 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.

This document reduces inconsistencies in blast testing methodology and standardizes blast testing reporting (interpretation and documentation of blast results). This improved consistency of practice will facilitate direct comparison of results, testing repeatability, and identification of trends.

This specification shall apply to blast simulator testing where applicable including all aspects of the specification except those that are specific to open air explosive testing.

Any concerns or exceptions to this standard practice shall be addressed in writing in the proposal phase of projects.

Exceptions shall be granted only through written response from the U.S. Department of State Point of Contact (POC).

The U.S. Department of State POC shall be the technical program manager at the U.S. Bureau of Diplomatic Security, Physical Security Division, Research and Development Section (DS/PSD/RD, 1.

1.1 Purpose

The primary purpose of this practice is to define good commercial and customary practice in the United States of America 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 document shall be used for blast simulator testing where applicable.

1.2 Objectives

Objectives guiding the development of this practice are:

1) Formalize standard practices for conducting blast tests for RD applications.

2) Facilitate high quality, standardized results processing and reporting of test results.

3) Use the RD standard practice as a starting point for a best practice document that will grow into an industry standard both domestically and internationally.

4) It is anticipated this document will evolve over time as requirements and facility capabilities change.

5) This document 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 Imperial units are to be regarded as the standard. The values given in parentheses are for information only.

1.4 Safety, Health, and Environmental Practices

This standard does not purport to address safety and environmental 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 in accordance with appropriate governing standards, organizational standards, and generally accepted practice and to determine the applicability of regulatory limitations prior to use.

1.5 Omissions

The omission of any specific explosive, instrumentation type, material type or test configuration does not necessarily preclude its use in accordance with this Standard Practice as long as all applicable provisions are satisfied.

SOP for Blast Testing 2022 UNCLASSIFIED 08/22/2022 Page 3 of 21

2.

This section provides definitions, descriptions of terms, and a list of acronyms for many of the terms used in this standard practice. The terms are an integral part of this practice and are critical to an understanding of this practice and its use.

2.1 Definitions

2.1.1 ANFO, n An acronym for Ammonium Nitrate, Fuel Oil. A common, stable and relatively inexpensive explosive commonly used for blast testing. ANFO is a mixture of technical grade (TG) ammonium nitrate (AN) prills and fuel oil (FO), often #2 diesel fuel. By weight, approximately 94% AN and 6% FO. Per Section 4.5, non-under this standard.

2.1.2 Approved, adj Acceptable to the authority having jurisdiction (last paragraph, Introduction and Executive Summary Section)

2.1.3 Blast, n A synonym for explosion.

2.1.4 Blast Load, n The load applied from a blast wave, which is described by the combination of pressure, impulse, and duration.

2.1.5 Blast Simulator, n A device or system using a high energy source to generate a target pressure versus time history having a positive phase shape, pressure, and impulse that replicates airblast pressure loads. Airblast negative phase pressure-time history may not be duplicated.

2.1.6 Clearing Effects, n Clearing effects

pressure waves diffracting around the edges of a structure which in turn generates a relief wave propagating inward from the edges. The effect of these relief waves is to reduce the amount of pressure acting on the structure during the blast event, thereby reducing the impulse placed on the structure.

2.1.7 DAQ, n An acronym for Data Acquisition System (also known as DAS).

2.1.8 Dynamic Response, n Deformation, stress and other behavior of structure or structural element due to the action of a time-varying loading while considering inertial, stiffness, and, in some cases, damping effects.

2.1.9 Equivalent Weight of TNT, n One measure of the energy (power) contained in a given amount of a specified explosive expressed as the weight of TNT which would result in the same peak pressure or impulse, all other parameters being equal. A number generally ranging between 0.7 and 1.7. Note that for some explosives the equivalent weight can differ depending upon whether comparing peak pressures or impulses.

2.1.10 Explosion, n A rapid chemical reaction that produces noise, heat, and a rapid violent expansion of gases.

2.1.11 Explosive, n A material or device that is capable of causing an explosion under certain conditions, such as heat, shock, electrostatic discharge or friction.

2.1.12 Far Range, n Standoff at which the blast loading from an explosion can be considered to be uniformly distributed over the tributary area of the element to be loaded. This corresponds to a scaled distance Z that is equal to or greater than 1.2 m/kg^1/3 (3.0 ft/lb^1/3).

2.1.13 Fixturing, n Devices or assemblies that may be used as interfaces between the test article and the test frame or reaction structure. Most often the fixturing is intended to provide realistic local support conditions for the test article.

2.1.14 Generally Accepted Practice Generally accepted practice in this document corresponds to means or methods that are commonly known or generally accepted in the community of blast effects on structural devices and systems.

2.1.15 Impulse, n Cumulative blast loading over time, calculated as the area under a pressure-time plot.

2.1.16 Near Range, n Standoff at which the explosive is in close proximity to the test article relative to the size of the explosive, such that the resulting blast loading must be considered to be non-uniformly distributed over the

SOP for Blast Testing 2022 UNCLASSIFIED 08/22/2022 Page 4 of 21 tributary area of the element being loaded. This corresponds to a scaled distance Z that is less than 1.2 m/kg^1/3 (3.0 ft/lb^1/3).

2.1.17 Nonresponding, adj Often used to describe a reaction structure and test frame. Nonresponding is a term used to describe a support system wherein the response of the support structure does not influence the response of the tested article.

2.1.18 Reaction Structure, n A structure used to support the test article, test frame and fixturing during the blast event. The reaction structure normally has large mass and stiffness compared with the anticipated loading and response of the test article. Examples include reinforced concrete boxed-shaped rooms, reinforced concrete culverts or containers filled with soil positioned behind the test frames. Another example may be a test frame mounted to a sled with the sled held in place by concrete blocks or possibly sand bags.

2.1.19 Rigid, adj Most often used to describe a structural component or system that has very high strength and very small deformations or deflections relative to the loading and accordingly has a very small effect on the response of the test article.

2.1.20 Scaled Distance Z, n The ratio of the standoff to the cube root of the explosive charge size as an equivalent mass of trinitrotoluene (TNT), which commonly serves as the basis for determining the blast loading parameters.

2.1.21 Standoff, n The physical distance between the surface of a building, or part thereof, and the potential location for an explosion. Most often the standoff is measured to the center of the charge. As there may be exceptions, it is important that the standoff be clearly defined in the test plan.

2.1.22 Test Plan, n A formalized plan, in writing, detailing the objectives, resources, and process(es) for a specific test, to be created and approved before a test occurs, preferably well in advance of said test.

2.1.23 Test Performer, n Organization, company or laboratory charged with the task of planning and executing the test(s) and with producing the appropriate deliverables related to test(s). The test performer may include personnel associated with the test facility.

2.1.24 Test Article, n Device or system being tested or evaluated.

2.1.25 Test Facility, n Physical infrastructure, equipment, items, and devices required for the execution of blast tests including geographical area (blast range), reaction structure, instrumentation, equipment, tools, power sources, and the like.

2.1.26 Test Frame, n A test frame is often used as a means of structural connection between the test article and the reaction structure. Test frames are most often constructed from either reinforced concrete or steel assemblies.

An example would include a tilt-up reinforced concrete wall placed in front of and rigidly attached to a reaction structure. The test article may be attached directly to the test frame or there may fixturing included to serve as the interface between the test frame and the test article.

2.1.27 Witness Panel, n A panel placed on the protected side of a test article that is used to document spall or fragmentation, typically from a test article containing glazing.

2.2 Symbols and Notation

ANFO - Ammonium nitrate, fuel oil td - Duration of positive phase, ms (msec)

TNT - Trinitrotoluene

Us - Shock front velocity, m/ms (ft/msec)

W - Explosive size as an equivalent quantity of TNT, kg (lb)

Z - Scaled distance, R/W^1/3, m/kg^1/3 (ft/lb^1/3)

SOP for Blast Testing 2022 UNCLASSIFIED 08/22/2022 Page 5 of 21

3.

Uses This practice in total is required for RD open airblast 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 RD.

4.

4.1 Topography The topography immediately adjacent to the location of the explosive charge must be approximately level (1 ft rise or fall in 100 ft) from the charge to 25% of the standoff past the target within an arc encompassing 30 degrees on either side of the reaction structure. Additionally, the area outside the arc shall be clear of any geometrical shapes or items that may inadvertently cause reflective or secondary loads on the target. Grade slope and reflecting surface behind the charge should be avoided.

4.2 Camera Vantage Points The test range shall provide sufficient camera vantage points situated to have an unobstructed view of all active test (reaction) structures and of the charge location. The vantage point(s) shall be sited so as to offer a side view of the hemispherical blast wave striking the front of the test (reaction) structure with at least one (1) camera for each active test (reaction) structure. The blast test plan may dictate other additional camera vantage points to provide other views.

4.3 Blast Pad for Open Airblast Testing Beneath the charge location, a blast pad shall be provided to minimize the influence of the local soil and/or substrate on the blast test results. The blast pad shall consist of either a concrete slab or a steel plate. The blast pad shall completely bear upon firm in-situ soil or fill material. The top

(50 mm) about the surrounding grade. In cases of repeated tests, blast pads may be re-used with careful evaluation of condition after each test. An exception to requiring blast pads may be considered in cases where extremely hard and durable substrate is withi (300 mm) of the surface under the charge (shallow bedrock as an example).

4.3.1 Concrete Pads Concrete pads shall be normal-weight concrete and shall have a 28-day compressive strength of no less than 3000 psi (20.7 MPa). Unless directed otherwise the c (244x244x23 cm). Concrete blast pad reinforcement requirements are the responsibility of the test performer but shall be a minimum of #3 rebar spaced at (10M spaced at 46 cm) each face and each way.

4.3.2 Steel Plate The opti (244x244 cm (25

mm). It shall be made in one piece (by welding plates together if required) and shall be made of mild steel (ductile steel).

4.4 Clean Power All powered equipment at the test range, whether at the cameras, sensors, data not cluttered with extraneous electrical noise. A portable option includes generators with built-in inverters.

4.5 Handling of Explosives The test performer shall have written procedures for handling, storing, tracking, and disposing of explosives. Minimum record maintenance should include purchase or shipment: the purchase date, lot number, vendor name, and specific technical information regarding explosive yield. For ANFO, non-not be used under the scope of this standard. Unless specified by the manufacturer, the use-by date for ANFO is defined as 6 months from date of purchase and not to exceed 9 months from the date of manufacture.

5.

Instrumentation requirements may vary considerably based on the nature of the test article and the load condition of interest. A given test may include more than one test article. This section provides general guidance for instrumentation sensors, devices, and systems as they are applicable to a given test.

5.1 Pressure Transducers Pressure transducers shall be provided in accordance with ASTM F1642.

Additionally, pressure gauges shall be mounted so as to minimize localized clearing effects (e.g., mounted flush

SOP for Blast Testing 2022 UNCLASSIFIED 08/22/2022 Page 6 of 21 with the face of the reaction structure) and structural response induced noise (see also Section 5.11). Techniques that involve covering the front of the gauge with soft materials like tape or silicone grease, may be used to mitigate extraneous noise if accompanied by clearly documented evidence that the technique does not significantly affect the pressure wave measurement.

5.2 Displacement Measurements Displacement measurements may be obtained by some combination of the following devices or methods. In general, displacement gauge accuracy, measured range of movement, and sampling rate should be selected in accordance with the predicted movements of the tested device. General comments regarding application and challenges include those in Sections 5.2.1-5.2.6:

5.2.1 Optical / Laser Gauges Gauges may be used in cases where debris and dust do not interfere with the signal. Excessive movement of the measurement point may also cause the signal to be lost mid-test. Flash from explosive detonation may also need to be addressed to avoid interference with proper signal. This is typically accomplished by covering any transparent test specimen with an opaque covering.

5.2.2 Rod Deflection Potentiometers Rod deflection potentiometer gauges (rack and pinion gauges) are often used in blast testing, especially where there is considerable dust and debris. Concerns include attachment of the rack to test article, column buckling of the rack, and whip of the rack during the response. Attachment of the rack to the tested article shall not damage the article (particularly in the case of glass) and must provide for displacement measurement through inbound and outbound response of the tested article. The rack shall be stiff enough to minimize buckling and / or lateral whip that can affect displacement measurement. The mass of the rack should be as small as practicable so as to minimize the possible effect on dynamic response of the tested article.

5.2.3 String Potentiometers String potentiometers (cable-extension position transducers also known as yo-yo gauges) may be used with the caveat that the rate of cable recoil is limited to a maximum acceleration. Exceeding that acceleration can result in measurement error or, in the case of backlash, total measurement loss. The device is sensitive to small debris and dust interfering with the cable movement and/or introducing extraneous cable movement, thereby effecting the displacement measurement.

5.2.4 Accelerometers Accelerometers (discussed in Section 5.3) may be used to measure acceleration at key locations with displacements calculated via two numerical integrations to calculate velocity and displacements. The ve as backup to other direct measurements.

5.2.5 Global Movement of Reaction Structure The global pre- to post-test movement of the reaction structure shall be measured relative a fixed reference. The intent is to document net movement due to sliding or shift of the structure resulting from the applied blast load. The measurement accuracy shall be within +/- -3 mm).

5.2.6 Other Displacement Measurements Various other techniques may be employed like fiducial markers coupled with high-speed cameras, strain visualization, or other techniques as approved by RD. A completely different technology involves piezo pin sensors that may be used to measure global displacements by activating when contact is made with the piezo material in the tip of the pin. In blast application the pins are often destroyed.

In all cases, there shall be well documented evidence regarding the efficacy of the method.

5.3 Acceleration Measurements Accelerometers may be used to characterize response versus time for the tested device or for the reaction structure. Care should be taken regarding general issues like sensitivity, amplitude range, decay time, drift, and mounting (see also Section 5.11). It is crucial that the linear frequency range of the accelerometer encompass the primary response frequencies of the tested device coupled with the reaction structure.

5.4 Direct Force Measurement Direct force measurement may be obtained through strain measurements of key structural components or implementation of load cells.

5.4.1 Load Cells In the case of load cells, the range and sensitivity of the load cell must capture the force response over both the inbound and outbound portions of the response. Accordingly, any preload applied before the load event must be large enough to account for rebound loading. A critical consideration is the mounting of the load cell (see also Section 5.11). Any residual permanent displacement that may influence the accuracy of the load cell force measurement shall be limited to less than 5% of the gauge displacement corresponding to the maximum force measured.

5.5 Strain Measurement Strain measurements are most reliably obtained using strain gauges mounted directly to structural components (see also Section 5.11). The selection of the gauges must include consideration for the material and surface being instrumented as well as the range and linearity of strain values. Particular care must be taken when strains exceed the elastic limit of metals. In all cases the strain gauges shall be selected, installed, SOP for Blast Testing 2022 UNCLASSIFIED 08/22/2022 Page 7 of 21 protected, an recommendations. Optical strain measurement and strain visualization techniques may be used when supported by well documented evidence regarding the effectiveness of the techniques in applications similar to the planned test.

5.6 Temperature Measurement Temperatures of the tested device may be measured using suitable devices including thermocouples, infrared camera, and the like. The primary concern is that key tested article temperatures are measured and recorded as close as possible to the time of detonation.

5.7 Photographs Digital photographs shall be taken with a camera having a minimum resolution of 8 megapixels.

5.8 Video Various videos may be required using a combinations color, black & white, real time, high-speed and disposable cameras. In this context a high-speed camera shall have a frame rate of no less than 1000 frames per second (fps). High-speed video shall include a time counter on the video suitable for measuring time steps between frames. Time counter on all video shall reference time zero (0:00) from time of detonation unless otherwise specified. The test performer shall ensure that the video recording equipment has the capacity to capture the full event as pre-determined in cooperation with RD and in accordance with Section 8.4.

5.9 Witness Panel A witness panel is often required as a means of qualifying and quantifying the amount of fragmentation that either passes or is expelled from the tested article. The specific materials of construction and configuration of the witness panel shall be documented in the test plan and test report.

5.10 Redundancy and Correlation As much as practicable, a variety of gauges or gauge types shall be used to provide redundancy particularly in cases where gauges or gauge signals may be lost during a test.

Correlation between, for example, accelerations and global movements or strains and displacements may be facilitated through careful selection and placement of gauges.

5.11 Mounting Cameras and Sensors Cameras and sensors shall be supported or attached in such a manner as to minimize spurious dynamic movements that may clutter or bias images or data.

5.12 Data Acquisition System (DAQ) The DAQ shall consist of a digital recording system with a sufficient number of channels to simultaneously accommodate the desired number of sensors and transducers. The DAQ shall operate at a sufficiently high frequency to reliably record the peak positive pressure. The DAQ shall also incorporate filters to preclude alias frequency effects on the data.

5.13 Calibration and Validation

5.13.1 Calibration All sensors (pressure, deflection, acceleration, etc.) shall have been calibrated by the sensor manufacturer p two (2) years prior to the test date. All calibration records shall be included as an annex to the test report.

5.13.2 Pre-test Check of Instrumentation Bench top or similar testing of sensors and instrumentation shall be performed prior to but not to exceed six (6) months before the test time. The results shall be compared against standard signals or measurements to demonstrate a consistency within 2% of the standards. Sensor connectivity tests shall be performed immediately before the event. Documentation of the pre-test check shall be available to RD before the test and shall be included with the final report. Results shall be reviewed by the test performer between tests to ascertain validity of the data.

5.13.3 Modifications to Test Plan RD shall be notified of any modifications to the test plan as well as changes to instrumentation and test article condition as soon as practicable. There shall be as much notice as practicable for evaluation of the possible impact on results. If there is the potential for any impact on the results, then the test may need to be rescheduled until the issue can be remedied.

6.

6.1 Nonresponding Structure The test article (device or system) shall be supported by a structure deemed as nonresponding. Nonresponding is a term used to describe a support system wherein the response of the support structure does not influence the response of the test article. Ideally, in numerical terms, the maximum dynamic displacement of any and all interface points between the test article or fixturing connection to the test frame and the reaction structure shall be limited to 5% of the maximum displacement of the tested article (see also Section 5.2.5). Alternatively, the period of the lowest frequency mode shape indicating movement of the interface front

SOP for Blast Testing 2022 UNCLASSIFIED 08/22/2022 Page 8 of 21 shall be limited to the predicted positive phase duration (td) divided by twenty (20). Numerical results may be demonstrated by calculation or prior test results and should be presented with appropriate documentation provided prior to the test. Calibration and / or validation tests at full load may be used to document the reaction structure response before testing of the actual subject articles or systems.

6.2 Elastic to the Load Components of the support system including the reaction structure and the test deformations. Supporting calculations or previous test results are required to be submitted to RD prior to the test.

Incidental yielding like small cracks in reinforced concrete panels or localized yielding of support system connections may be acceptable. In all cases, acceptance of incidental yielding shall be at the discretion of RD Incidental yielding shall be documented in writing and included in the final test report.

6.3 Fixturing and Test Article Mounting Fixtures and mounting devices used to facilitate the structural interface and installation of test articles with the reaction structure shall be consistent with manufacturer recommendations or applicable design drawings. In the absence of either, calculations shall be performed and submitted that demonstrate the adequacy of the mounting scheme. Any deviation from manufacturer recommendations or design drawings shall be documented. Examples of deviations might include through-bolted connections in lieu of drilled and tapped connections or expansion type concrete anchors in lieu of epoxy anchors.

6.4 Global Movement Mitigation Consistent with the notions above, the test frame or reaction structure shall be designed or configured to minimize global movement particularly in the form of horizontal sliding. As the global movement is part of the total limit in the nonresponding structure paragraph above, it is strongly recommended that steps be taken to mitigate global movement. The movement of the reaction structure relative to a fixed reference point shall be measured and documented from pre- to post-test.

6.5 Face of Reaction Structure The face of the reaction structure shall not have holes or voids that might allow leakage of blast pressure through the face. There shall be no appurtenances or divots that might introduce localized shock wave eddies or clearing particularly in close proximity to pressure gauges. Pressure transducers shall be mounted flush with the face of the structure.

6.6 Reflections If more than one test structure is located in the blast arena, consideration shall be given as to whether the proximity of the nearby structure(s) or changes in topography and possible blast wave reflections might have a detrimental effect on the test results.

6.7 Enclosed Space Behind Test Article If the test article is designed to function with an enclosed space behind it, such as would be the case for the outer wall system of a building, then the reaction structure shall feature an enclosed space immediately behind the test article. The enclosed space shall serve both to simulate interior building space and provide access to, and protection of instrumentation. The design shall be such that pressure waves wrapping around the test structure will not be able to enter the enclosed space and load the back side of the test articles. The pressure inside the structure shall be recorded and included with the final test report.

6.8 Clearing Effects The reaction structure shall be proportioned or shall have contiguous structure for a suitable distance from the edges of test article such that the clearing effects do not cause significant reduction in the reflected impulse at the test article. Planned mitigation of the clearing effects shall be documented prior to the test and shall be supported by either calculation or by previous test results.

6.9 Reaction Structure Construction Specifics The test performer is required to provide specific information regarding the construction of the reaction structure so as to facilitate modelling where dynamic coupling of the test article with the reaction structure may be of concern. The specific information would be in the form of material of construction, mechanical properties, member sizes, and connection details.

7.

A test plan is required for submission to RD with ample calendar time to allow at least one review and comment by RD with final edit by the test performer. RD shall have final approval of the test plan. In addition to explicitly addressing each item in Sections 4, 5, and 6, the test plan shall include the following components:

7.1 Test Article(s) A general description of test article shall be included. Supporting drawings, sketches, calculations, and background information shall be included in an annex. Details should be included or documents should be referenced that provide enough specific information such that the article can be reproduced or

SOP for Blast Testing 2022 UNCLASSIFIED 08/22/2022 Page 9 of 21 reconstructed without any additional specific knowledge regarding the article. Documentation shall address fixturing and mounting of test article.

7.2 Blast Loading Blast loading will either be defined in terms of TNT equivalence and standoff, or reflective pressure and impulse. Note that in either case, it may be required to present the explosive load in symbolic form with no explicit values shown. In that case, separate communications with RD may be required to document the values. Sketches drawn to scale shall be included that show the proximity of the charge to the target(s) and the reaction structure(s) with, at a minimum, an outline of the reaction structure frame(s) drawn to scale. The sketch shall include any clearing effects mitigation that may be included.

7.2.1 Specified TNT Equivalence In the case of TNT equivalence for explosive materials, documentation shall be provided to support the equivalent values with consideration for standoff distance. Given that TNT equivalence may differ for pressure versus impulse, there should a clear understanding and associated documentation regarding what combination of pressure versus impulse is assumed.

7.2.2 Specified Pressure and Impulse

7.2.2.1 Calibration Tests and Validation The test plan shall include documentation from previous tests or specifics details of how calibration tests will be executed as part of the preparation for the actual tests. Typically, calibration tests include gauges installed on panels that act as surrogates for the actual test article(s). As direct measurement of pressure and impulse on the test article may not be practical, gauges shall be installed near the edge of the test article for both the calibrations tests and the actual tests. Those gauges may then be used to evaluate the loading likely applied to the test article.

7.2.2.2 Pressure Gauge Redundancy Since pressure gauges have a propensity to yield spurious data, redundancy in pressure measurements is highly recommended. Provide redundancy by symmetric placement of gauges relative to the test article. Gauge redundancy should be taken into account to mitigate damaged or non-functioning gauges during the test event.

7.2.2.3 Targeted Pressure and Impulse The calibrated target reflected pressure and impulse shall be within +/- 10% of the specified reflective pressures and impulse. The calibrated reflective pressure and impulse shall be derived from a Modified Friedlander curve fit of the positive phase raw pressure data.

7.2.3 Shape and Configuration of Charge

7.2.3.1 TNT Equivalence 250lb or Greater Most often for TNT equivalent charges of 250lb (113.4kg) or greater the charge shape shall be that of a cylinder with the axis of the cylinder oriented in the vertical direction.

The height to diameter ratio shall be as close to one (1) as practicable. In the case of granular or prilled explosives like ANFO, the material is typically poured into a cylindrical cardboard tube as would be used for forming cylindrical concrete columns. The charge shall be placed on top of a frangible table with a height of 3 ground surface.

7.2.3.2 TNT Equivalence Less than 250lb For TNT equivalent charges of less than 250lb (113.4kg) the shape and configuration of the charge may vary considerably. The default configuration is as described above for 250lb or Greater. If the configuration is not explicitly provided in the statement of work, the testing agency shall confirm the configuration prior to submitting the test plan for review.

7.2.3.3 Specified Pressure and Impulse In cases where a target reflective pressure and impulse is specified, it shall be at the discretion of the test performer to select the charge shape and configuration.

7.2.4 Explosive Weight In all cases, the actual weight of the explosive shall be within +/- 1% of the planned weight of the explosive. The actual net weight shall be recorded and documented. As an example, in the case of ANFO, the facility might document the weight of each loaded bag minus the weight of each empty bag or the weight of a pallet loaded with full bags minus the pallet with the emptied bags.

7.2.5 Detonation Provide a description of the detonation plan including the type and placement of the detonator. Center detonation is considered the default method; this may be altered with the approval of RD.

7.3 Instrumentation Plan Sketches and other documentation shall be provided that indicates sensor type and location as well as camera placement. Technical data sheets for the various sensors, cameras and the DAQ shall be included in an appendix.

7.4 Reaction Structure Sketches shall be included that show the overall dimensions of the reaction structure including opening sizes, internal dimensions, clearing effects mitigation, and reference points for global movement of the reaction structure. The mass of the reaction structure shall be documented. Supporting documentation shall be provided regarding the structural response of the reaction structure as related to it and

SOP for Blast Testing 2022 UNCLASSIFIED 08/22/2022 Page 10 of 21 ancillary components being nonresponding and elastic to the load. Provide documentation in the form of calculations or previous test reports that support the mitigation of clearing effect on the load at the target(s).

7.5 Witness Panel Witness panel(s) may be required in some tests. If so, then witness panel dimensions, material, location(s), and construction details shall be included. Sketches showing an elevation view of the target with a to-scale outline of the corresponding witness panel shall be included in the test plan as well as the final test report.

8.

8.1 Test Site Visit by RD In addition to pre-test walk though, test witnessing and post-test review of results, RD may opt for and be accommodated with additional test site time including but not limited to what is described in Sections 8.1.1-8.1.3.

8.1.1 Setup Being present during portions of the test article installation and test setup for observation and possible test article or test plan refinements.

8.1.2 Pre-Test Walkthrough Performing walk through and observation the day before the test where final adjustments and refinements to the setup may be requested.

8.1.3 Post-Test Examination Performing post-test forensics on the day(s) after the test event.

8.2 As-Tested Article

8.2.1 Fabrication The as-fabricated test article shall be fully documented as related to deviation from the design drawing, sketches, or calculations. Any available insights into possible improvement in details as related to ease and cost of fabrication should be noted.

8.2.2 Installation The as-installed configuration shall be fully documented with particular attention to issues like shim gaps and bolt torques. Any deviation from manufacturer recommendations or installation details shall be documented. Any possible insights into modifications to facilitate installation shall be documented.

8.2.3 Materials of Construction All test articles, fixturing and mounting supplied by the test performer or test facility shall be fully documented as to the as-tested mechanical properties. There is a distinction between as-designed, specified or ordered properties and the actual as-tested properties. An example is that of structural steels where the actual yield and tensile strengths are much higher that the specified minimum. Proper tracking and documentation of steel product includes mill test reports for the specific lot of steel where yield, tensile and elongation are reported. Another example is the need to require documentation of bolt strength certification. A further example is that as-placed concrete strength is most often much higher than the as-ordered concrete. Twenty-eight (28) day compressive tests shall be executed and documented for the as-placed or as-constructed concrete.

Fully document glazing layup materials and thicknesses including but not limited to: glass, polycarbonate, interlayer, structural silicone, and gasket component mechanical properties.

8.3 Reporting Deviations In addition to documenting any deviations in the instrumentation, test plan or test article, those deviations shall be communicated to RD in writing before the test is executed. That communication shall include visual observation at the test site before the test when appropriate.

8.4 On Site Documentation by RD RD shall have full authority over whether visitors are allowed to photograph or video any aspect of the test setup, execution and results. The test performer shall have the right to control or review and delete background and surrounding images that may not be germane to the test.

8.5 On Site Review of Results RD shall be given the opportunity to review data including videos as soon as practicable after the test. Technicians shall be available to obtain selected peak pressures, displacements, and the like while RD is still on site. Video play backs shall also be available to RD before leaving the site.

8.6 Range Safety The range safety officer (or equivalent) shall have authority over access and conduct of visitors in issues where there may be a concern over human safety or health.

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9.

9.1 Raw Data All raw data from all sensors, recorded during both calibration blasts and test blasts, shall be retained in digital form and be delivered as supplementary information to accompany the final test report.

9.2 Processed Data Any processing or reduction of raw data in the form of curve fits, smoothing, shifting and truncating shall be documented with complete details describing the specific steps or mathematical operations involved.

9.3 Time Scale All sensor data and video recordings shall have synchronized time scales with time zero at time of detonation. The time scale shall be truncated to td before detonation until the end of the negative phase and until significant test article response has ended.

9.4 Videos Videos shall have a duration that capture the event but shall be truncated so as to minimize length and storage requirements. The viewing time shall be truncated to start approximately 2 seconds before detonation and stop after the end of the negative phase, when significant test article response has ended, and / or when the shock wave and debris have dissipated or settled. Title slides shall be visible no longer than 2 seconds followed by the 2 second delay before the shot initiation. Videos shall be saved in a format that is readily viewable using software tools commonly available at the time at which the videos were recorded.

9.5 Peak Pressure In addition to plotted curves for blast pressure versus time, peak pressures at the various sensors shall be obtained and tabulated using a Modified Friedlander curve fit for the positive phase of the blast pressure versus time history data. Other forms of curve fits may be used, for example, for the negative phase of the pressure curve. However, for RD purposes, the reported values for peak pressure are to be derived explicitly from the Modified Friedlander form and the positive phase data only. The curve fit shall be shown on the curves included in the report, and a digital form of the processed data with curve fits shall be included as a deliverable with the final test report. A comparison between the raw data peak pressure and the curve fit result shall be included.

9.6 Impulse Calculation Impulse shall be calculated by integration of the pressure versus time data. As a check on the curve fit to the positive phase, it is suggested that the curve fit result be integrated for comparison of peak impulse from the integration of the actual pressure data.

10.

The test report shall include but not be limited to: test plan, calculations, drawings, sketches, measurements, component properties, results, observations, deviations, photos, witness panel results, data plots, raw data, processed data, and videos.

10.1 References Any and all references in this specification to documentation or deliverables shall be included in the main report, as annexes of the main report, or referenced by the report. Complete copies of referenced information shall be delivered to RD as part of the report package, except for third-party documents or standards that are protected by copyrights.

10.2 Results All raw and processed data in a digital format shall be included as part of the report package, as applicable or as data is available, to include but not be limited to:

- Digital forms of plotted data shall be provided in Dplot format. Dplot graphs shall be generated to include axis descriptions, units, and graph title. Copies of Dplot graph(s) shall be provided in PDF format.

- Metrics for assessing test results (e.g., operability of doors or fragmentation of glass).

- Summary tables comparing predicted values of loading and responses with measured values.

Include calculations of scaled distance along with a narrative related to the validity of the scaled distance as related to blast load predictions with consideration for far range versus near range effects.

Provide narrative and applicable calculations documenting effects that may cause differences in predicted versus measure values.

- Any instrumentation failure or measurement anomalies shall be documented.

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- Documentation of process used to smooth, filter and curve-fit sensor data.

- Documentation of the post-test condition of fixturing, mounting systems, and reaction structure including fasteners, weldments, concrete components, and concrete anchors.

10.3 Setup Test reports shall include information required to replicate the load events where RD may seek to reproduce the event in future tests. For airblast tests the information includes explosive material, charge configuration, detonation plan, etc. as indicated in Sections 5, 6, and 7. One example of a blast simulator is a shock tube where a shock wave is generated by quick release of compressed gas. In that example the information shall include shock tube model number, configuration, driver gas, vent configuration, driver length, driver pressure, rarefaction wave mitigation method, and rupture panel material and thickness.

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ANNEX

(Mandatory Information)

Item (documentation) Yes No N/A Comments

Test article details

Sketch of charge relative to target

TNT equivalence

P&I calibration

Shape and Configuration of Charge

Explosive weight documentation plan

Detonation plan

Instrumentation plan

Technical data for instrumentation

Reaction structure dimensions

Reaction structure response calculations

Nonresponding and elastic to the load

Clearing effects mitigation

Witness panel sketches and details

Test frame design

Test plan checklist

N/A Not Applicable

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Item (documentation) Yes No N/A Comments

Test article details

Sketch of charge relative to target

P&I calibration

Instrumentation plan

Technical data for instrumentation

Reaction structure dimensions

Reaction structure response calculations

Nonresponding and elastic to the load

Target wall dimensions

Test frame design

Witness panel sketches and details

Simulator description

Simulator configuration

Simulator blast wave source

Plan for replication of load conditions

Test plan checklist

N/A Not Applicable

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APPENDIX

(Nonmandatory Information)

Use current version.

ASTM Standards

F1642 Standard Test Method for Glazing and Glazing Systems Subject to Airblast Loadings

F2912 Standard Specification for Glazing and Glazing Systems Subject to Airblast Loadings

F2927 Standard Test Method for Door Systems Subject to Airblast Loadings

F2247 Standard Test Method for Metal Doors used in Blast Resistant Applications

Other Standards and Manuals

ASCE/SEI 59 Blast Protection of Buildings

Department of Defense 5220.220-M National Industrial Security Program Operating Manual (NISPOM)

DOE TIC 11268 A Manual for the Prediction of Blast and Fragment Loadings on Structures

Dplot User Manual

GSA-TSA01 Standard Test Method for Glazing and Window Systems Subject to Dynamic Overpressure Loadings

ISEE Blaster's Handbook, 18th Edition

ISO 10012 Measurement Management Systems - Requirements for Measurement Systems and Measuring Equipment

ISO IEC 17025 General Requirements for the Competence of Testing and Calibration Laboratories

MIL-HBK-1013 Evaluation and Selection of Security Glazing for Protection Against Ballistic, Bomb and Forced Entry Tactics

MIL-STD-810G with Change 1 Department of Defense Test Method Standard

Navy Blast Resistant Structures Design Manual 2.08

PDC-TR-05-01 Single Degree of Freedom Blast Effects Design Spreadsheets (SBEDS)

PDC-TR-06-01 Rev 1 Methodology Manual for the Single Degree of Freedom Blast Effects Design

Spreadsheets PDC-TR-06-08 SDOF Structure Response Limits for Anti-Terrorism Design

UFC 3-340-02 Structures to Resist the Effects of Accidental Explosions

UFC 4-010-01 DOD Minimum Anti-Terrorism Standards for Buildings

UFC 4-010-02 DOD Minimum Anti-Terrorism Standoff Distances for Buildings

WinGard PE User Guide

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Definitions (extensive list includes some items from main document)

ANFO, n An acronym for Ammonium Nitrate, Fuel Oil. A common, stable and relatively cheap explosive commonly used for blast testing. ANFO is a mixture of technical grade (TG) ammonium nitrate (AN) prills and fuel oil (FO), often #2 diesel fuel. By weight, approximately 94% AN and 6% FO.

Annex, n Includes any detailed information that is a mandatory part of the specification but may be too lengthy for inclusion in the main text. Annexes precede appendixes

Appendix, n dditional information for general use and guidance, but which does not constitute a mandatory part of the specification.

Approved, adj Acceptable to the authority having jurisdiction.

Blast, n A synonym for explosion.

Blast Load, n The load applied from a blast wave, which is described by the combination of pressure, impulse, and duration.

Blast Simulator, n A device or system using a high energy source to generate a target pressure versus time history having a positive phase shape, pressure, and impulse that replicates airblast pressure loads. Airblast negative phase pressure-time history may not be duplicated.

Computational Fluid Dynamics, n A branch of fluid mechanics that uses numerical analysis and data structures to analyze and solve problems involving fluid flows.