ISO 16933:2007

INTERNATIONAL ISO
STANDARD 16933
First edition
2007-07-01

Glass in building — Explosion-resistant
security glazing — Test and classification
for arena air-blast loading
Verre dans la construction — Vitrages de sécurité résistant à
une explosion — Essai et classification par charge circulaire d'air




Reference number
ISO 16933:2007(E)
©
ISO 2007

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ISO 16933:2007(E)
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ISO 16933:2007(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Hazard rating . 3
5 Test specimens . 3
6 Facilities and equipment preparation. 4
7 Test procedure . 7
8 Classification criteria. 9
9 Test report . 12
10 Precision and bias . 13
Annex A (normative) Blast parameters and derivation. 14
Annex B (informative) Characteristics of blast shock waves and explosives. 16
Annex C (informative) Nominal charge size and standoff distances. 19
Annex D (informative) Fragment definitions and criteria comparisons . 21
Bibliography . 22

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ISO 16933:2007(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 16933 was prepared by Technical Committee ISO/TC 160, Glass in building, Subcommittee SC 2, Use
considerations.

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ISO 16933:2007(E)
Introduction
This International Standard provides a method for carrying out arena blast tests in order to assess and classify
the response of glazing to the overpressure and impulse characteristics of high-explosive blasts. This
International Standard provides criteria for rating the level of damage to the glazing and the hazard
consequences to the area located behind the glazing. The increasing use of glazing designed to protect
persons and property from accidental explosions, and from the effects of terrorist attacks with high explosives,
has prompted the preparation of this International Standard.
Structural response to blast loading is dependent upon specimen size and edge constraint as well as material
composition and thickness. The classifications and test results derived by using this International Standard
can be used in conjunction with calculation procedures and further validation tests on framed glass during the
process of designing complete glazing systems against explosive threats.
The following annexes are included in this International Standard:
⎯ Annex A (normative) Blast parameters and derivation
⎯ Annex B (informative) Characteristics of blast shock waves and explosives
⎯ Annex C (informative) Nominal charge size and standoff distances
⎯ Annex D (informative) Fragment dimensions and criteria comparisons

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INTERNATIONAL STANDARD ISO 16933:2007(E)

Glass in building — Explosion-resistant security glazing — Test
and classification for arena air-blast loading
1 Scope
This International Standard provides a structured procedure to determine the air-blast resistance of glazing
and sets forth the required apparatus, procedures, specimens, other requirements and guidelines for
conducting arena air-blast tests of security glazing. Seven standard blasts simulating vehicle bombs and
seven standard blasts simulating smaller satchel bombs that can be used to classify glazing performance are
incorporated in this International Standard and cover a broad range of blast parameters.
Security glazing, including that fabricated from glass, plastic glazing sheet material, glass-clad plastics,
laminated glass, insulated glass, glass/plastic glazing materials and film-backed glass, can be tested and
classified in a standard frame or tested but not classified in frames provided with the glazing.
Classification and ratings are assigned based on the performance of glazing loaded by air-blast pressures and
impulses, and are specific to the blast characteristics under which the test takes place. Glazing that has
received an air-blast classification and rating is suitable for use in blast-resistant applications only for blasts of
comparable characteristics and only if installed in a properly designed frame. Design based on knowledge of
the air-blast resistance reduces the risk of personal injury.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 48:1994, Rubber, vulcanized or thermoplastic — Determination of hardness (hardness between 10 IRHD
and 100 IRHD)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
air-blast pressure history
description of the pressure of a reflected or free-field air blast, as measured at a point on the surface and
consisting of two separate phases:
⎯ positive phase, which is characterized by a nearly instantaneous rise to a maximum pressure followed by
an exponential decay to ambient pressure;
⎯ negative phase, immediately following the positive phase, during which the pressure decreases below
ambient for a period of time before returning to ambient
3.2
ambient temperature
temperature at which the test is conducted
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ISO 16933:2007(E)
3.3
blast mat
steel or concrete pad upon or above which a high explosive may be detonated to reduce the incidence of
ejecta
3.4
breach
any perforation or opening through the test specimen or between the test specimen and the support frame,
evident after the test, through which a 10 mm diameter rigid bar can be gently passed without force
NOTE An opening may be caused by the glazing sheet infill pulling away from the rebate sufficiently to result in a
visible gap that exposes the edge of the sheet.
3.5
cartridge paper
2
thick white paper for pencil and ink drawings, typically about 130 g/m
3.6
free-field air-blast pressure
blast pressure acting at any given point in the free field, where there is no structure or other object disturbing
the blast wave propagation
NOTE Also referred to as incident pressure, being the pressure measured on surfaces incidental to or parallel with
the direction of travel of the blast front.
3.7
fragment
any particle with a united dimension of 25 mm (1 in) or greater
NOTE The united dimension of a glass particle is determined by adding its width, length and thickness. Glazing dust,
slivers and all other smaller particles are not accounted as fragments.
3.8
glazing
glass or plastics glazing sheet material, including glass/plastic combinations
3.9
indents
any detectable deformation of the foil or cartridge paper surface of the witness panel caused by impact of any
material as a result of the blast
3.10
peak-positive air-blast pressure
maximum measured positive phase air-blast pressure
NOTE If the measured pressure-time trace has sharp irregularities, the trace should be smoothed to produce a
pressure-time trace that closely matches the mean path of the recorded trace. The peak pressure, P , of relevance is
max
the resulting smoothed value.
3.11
perforations
any holes in the foil, cartridge paper or plain surface of the witness panel caused by impact of any material as
a result of the blast
3.12
positive phase impulse
integral of the measured positive phase air-blast pressure history
3.13
reaction structure
all elements of the structure designed to support the test frame or alternative means for holding the glazing to
be tested
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ISO 16933:2007(E)
3.14
reflected air-blast pressure
pressure increase that a surface, oriented other than parallel to the line from the detonation point to the
surface, experiences due to the detonation of a high-explosive charge
3.15
standoff distance
perpendicular distance from the plane of the front surface of the glazing to the centre of the explosive charge
or from the centre of the glazing if not perpendicular to the explosive
3.16
test frame
reaction structure, to which are fastened all elements that are used to directly support the glazing during
classification of the glazing
3.17
witness panel
panel of deformable material positioned behind the test specimen in order to register the incidence of material
forcibly detached from the test specimen during test
NOTE The composition and location of the witness panel is described in 6.6.
4 Hazard rating
A hazard rating is applied to glazing based on its performance under the blast conditions chosen for the test.
The rating is specific only to those blast conditions.
5 Test specimens
5.1 Number of test specimens
For the purpose of classifying glazing a minimum of three test specimens, each
(1 100 ± 5 mm) mm × (900 ± 5) mm shall be tested at a given level of air blast, defined in terms of peak
positive air-blast pressure and positive phase impulse. One additional specimen shall be provided for pre-test
measurements. Glazing of other sizes may be tested if the manufacturer supplies framed glazing or frame
specifications. As such non-standard glazing assemblies may only be tested but not classified in accordance
with this standard, the number of test specimens will be as agreed prior to test.
5.2 Multiple specimens
The air-blast resistance capacity of glazing does not imply that a particular specimen resists the specific air
blast for which it is rated with a probability of 1,0. However, the probability that a single glazing or glazing
system will resist the specific air blast at the particular level for which it is rated increases proportionally with
the number of test specimens that successfully resist that air blast at that level. The protection afforded
against a blast by a single item of glazing depends not only upon the glazing but also upon the manner in
which it is attached to the structure in which it is mounted.
5.3 Handling and storage
The test specimens shall be handled and stored in compliance with the manufacturer’s instructions.
5.4 Marking
Each specimen shall be marked with the manufacturer’s model and serial numbers and the date of
manufacture. The attack side is intended to be oriented towards the explosive charge and shall be marked by
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ISO 16933:2007(E)
the manufacturer to assure proper installation in the test frame. A number shall be assigned to each test
specimen and shall be marked accordingly.
5.5 Measurements
Thickness measurements of the glazing material shall be made at each corner, 25 mm from each edge, and
recorded. If the specimens are supplied already mounted in a frame, one of the specimens shall be selected
at random and inspected for details. Measurements shall include the edge dimensions of the frame and the
glazing material, the cross-sectional dimensions of the frame and thickness measurements of the glazing
material. The frame and glazing materials shall be verified to comply with the manufacturer’s specifications.
Measurements and records shall be made of the bolts, screws or other devices used for fixing the test frame
or other glazing support system to the reaction structure.
5.6 Photography
Prior to the test, a photographic record that adequately portrays the test specimens, the test frame and the
test configuration shall be made. This photographic record shall consist of still photographs and may include
motion pictures or video.
6 Facilities and equipment preparation
6.1 Test facility
The test facility shall consist of an open-air arena located on clear and level terrain. The test facility shall be
situated, and of sufficient size, to safely accommodate detonation of the amount of explosive required to
provide the desired peak positive air-blast pressure and positive phase impulse. Potential environmental
impact issues shall be analyzed and resolved prior to testing. Unless otherwise specified, testing shall be
conducted at ambient temperature as defined in 3.2 and Clause 8.
6.2 High-explosive charge
A high-explosive charge shall be used to generate the desired peak positive air-blast pressure and positive
phase impulse on the test specimens. The explosive composition, shape, mass, height and location shall be
adjusted to meet these required parameters within the tolerances allowed.
6.3 Blast mat
If there is a possibility of crater ejecta interfering with the test, the high-explosive charge shall be placed on a
blast mat. The decision to use a blast mat, its size and thickness shall be at the discretion of the test director.
6.4 Test frame and reaction structure
For classifying the glazing, the following test frame and reaction structure requirements shall apply.
a) Test specimen(s), each with a vision size of 1 000 mm × 800 mm, shall be mounted on a test frame,
along the full length of all four edges. The test frame and reaction structure shall be capable of resisting
the air blast with deflections that do not exceed L/360, where L denotes the dimension of a test frame or
reaction structure member measured between the lines of support.
b) The test frame shall be fixed securely in a vertical position to the reaction structure. The test frame shall
be provided with clamping plates to hold each glazing in position and means for producing uniform
clamping of the glazing.
Bolt spacing of not more than 100 mm is recommended around the perimeter of each glazing.
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ISO 16933:2007(E)
c) The test specimens shall be mounted in a manner that meets the following requirements.
⎯ Mount standard-sized test specimens so that the bottom edge is between 0,5 m and 1,0 m above the
floor of the witness area.
⎯ Each test specimen shall have an edge capture of not less than 45 mm on all edges.
⎯ Each test specimen shall be separated from the test frame and the clamping plate by continuous
rubber strips (4 ± 0,5) mm thick, (50 ± 5) mm wide and of hardness (50 ± 10) IRHD in accordance
with ISO 48:1994.
⎯ At the bottom of the rebate, each test specimen shall be seated on rubber strips (4 ± 0,5) mm thick,
of hardness (50 ± 10) IRHD in accordance with ISO 48:1994 and of width equal to the full thickness
of the test piece.
⎯ All four edges of each test specimen shall be uniformly clamped with a clamping pressure of
2
(140 ± 30) kN/m .
NOTE The clamping pressure can have a significant effect on the test results.
d) If the glazing is supplied with its own unique frame or in a fenestration assembly, it shall be attached to
the reaction structure as directed by the manufacturer and in a manner that closely models the manner in
which it will be mounted in the field. Non-standard test specimens may be mounted at heights appropriate
to the manner in which they will be mounted in the field.
e) All test specimens and witness panels shall be completely enclosed in a structure designed to prevent air-
blast pressure from wrapping behind the test specimens.
f) Unless otherwise specified, each test frame shall be placed so that the test specimens are oriented
perpendicular to a line from the detonation point to the centre of the test frame in order that they
experience reflected pressures. The above directions assume such an orientation with the test specimen
mounted vertically. Any other orientation shall be agreed with the test sponsor in advance of testing and
shall be recorded as required in 9.1c) as it can affect failure modes and hazard ratings.
g) The classification blast values are based upon tests using reaction structures (test cubicles) having face
dimensions approximately 3 m × 3 m as described in Annex C. If the reaction structure is oriented
perpendicular to the line of the detonation point, the face of the reaction structure should not be less than
2,4 m wide × 2,4 m high. This is in order to avoid excessive reductions in reflected impulse that arise
owing to the effects of blast clearing from the edges of small targets. For further information on assessing
the blast relative to the size of the reaction structure, tests, criteria and effects on glazing, see
Reference [8].
6.5 Instrumentation
6.5.1 Pressure transducers
A minimum of three air-blast pressure transducers shall be mounted on the exterior of each reaction structure.
The air-blast pressure transducers shall be flush with the surface of the reaction structure on the air-blast side.
The transducers shall be located such that the pressure and impulse in the centre of each test specimen can
be computed. As an alternative, the pressure transducers may be installed on a transducer panel of the same
size as the test frame and located and oriented in the same manner with respect to the charge as the test
frame.
All pressure transducers shall be capable of defining the anticipated air-blast pressure history within the linear
range of the transducer. Each transducer shall have a rise/response time and resolution sufficient to capture
the complete event. Limited low-frequency response transducers shall have a discharge-time constant equal
to approximately 30 times to 50 times the initial positive phase duration of the anticipated air-blast pressure
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ISO 16933:2007(E)
history. Calibration records shall be maintained that demonstrate the equipment can measure pressure within
an accuracy of ± 5 %.
At least one free-field pressure transducer shall be used in each test. The free-field pressure transducer shall
be located at least 5 m or the width of the reaction structure, whichever is greater, from any reaction structure
and at the same horizontal distance from the high-explosive charge as the centre of the glazing.
Optionally, appropriate pressure transducers may also be located within the enclosure behind the glazing to
measure the pressure within the protected area during the blast. All pressure transducers shall be attached to
the data-acquisition system and tested prior to the blast to verify proper operation.
All pressure-time readings shall be examined to derive the peak pressure values from the smoothed path of
the measured trace. The individual peak pressure values subsequently recorded shall in each case be that
adjusted by smoothing as necessary to eliminate sharp spikes arising from recording and instrumentation
irregularities. The value derived from several of these individual, adjusted peak pressures for comparison with
the classification criteria is referred to as the “mean peak air-blast pressure", as in Clause 8 and Tables 2 and
3. Where a transducer panel is used, this is simply the “mean” or the “average” of the adjusted peak pressures
recorded by at least three transducers near the simulated centre of the target. Where blast measurements
have been taken from transducers around the edge of the test specimens, it can be necessary to derive the
“mean peak pressure” determined for the centre by more complex computation. For further information, see
Annexes A and B.
6.5.2 Data-acquisition system
The data-acquisition system shall consist of either an analog or a digital recording system with a sufficient
number of channels to accommodate all pressure transducers and any other electronic measuring devices.
The data-acquisition system shall operate at a minimum sampling rate of 100 000 samples per second (a
sampling interval of 0,01 ms) with a rise-time sensitivity response to peak pressure of 10 µs. A higher
sampling rate is recommended for the satchel tests. The system shall be capable of recording reliably the
peak positive air-blast pressure and the complete pressure-time trace through the negative phase loading as
well. The data-acquisition system shall also incorporate filters to exclude alias frequency effects from the data.
6.5.3 Photographic equipment
Adequate photographic equipment shall be available to document the test.
6.5.4 Temperature-measuring device
A temperature-measuring device shall be used to accurately measure glazing-surface temperature and air
temperature no more than 30 min prior to the blast.
6.6 Witness panels
A witness panel (3.17) shall be mounted behind each test specimen and inside the air-blast-resistant
enclosure, parallel to the plane of the test specimen. Unless otherwise specified, the witness panel shall be
placed (3 ± 0,15) m behind the test specimen. The witness panel shall cover the full area projected behind the
test specimen and extend down to the floor of the witness area. The witness panel shall have a width at least
that of the minimum permitted reaction structure defined in 6.4, or the width of the test specimen if greater,
and a height extending from the level of the collecting mat to 200 mm above the top of the test specimen, or
the ceiling of the reaction structure if less.
The witness panel shall consist of sheets of non-ductile, foam insulation board, of material equivalent to
3
extruded polystyrene, polyisocyanurate or urethane, of density (30 ± 5) kg/m . The board shall be in one or
two layers of combined thickness at least 35 mm, mounted in a frame capable of remaining in place even if
forcibly impacted by failed pieces of the test specimen. In order to aid recording of the damage and to reduce
waste, the board may contain a removable face layer at least 12 mm thick and the witness panel may be
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ISO 16933:2007(E)
1)
faced with contiguous sheets of aluminium foil of thickness not more than 0,025 mm or cartridge paper of
2 2
weight between 100 g/m and 150 g/m . The foil or cartridge paper surface shall be placed toward the window
glazing. To accommodate high-speed photography, a hole no greater than 150 mm × 150 mm may be made
in the top or bottom corner of the witness panel within an area bounded by one third of the height and width of
the panel.
7 Test procedure
7.1 Safety
The range safety officer, or the test director when acting as the range safety officer, is responsible for range
safety and procedures. When the test specimens have been mounted on test frames and the high explosives
has been placed and is ready to be armed, the area shall be cleared of all non-essential personnel. The high
explosive shall then be armed in a manner to maximize safety of personnel in the event of accidental
discharge of the explosive during the arming procedure. After the high explosive is armed and all personnel
are at a safe distance from the explosive, the explosion shall be triggered.
7.2 Initial inspection
When the blast area is safe to enter, an initial inspection of the test specimens shall be made. The apparent
condition of the test specimens shall be recorded. The length and location of any openings in the test
specimens and pullout of the glazing from the test frame shall be measured and recorded. The location and
description of all parts of the specimen shall be recorded, whether retained in the frame or fallen inside or
outside, with identification of inner and outer leaves of glass where appropriate.
Photographs of the test specimens shall be taken before beginning removal of test specimens.
7.3 Glazing and witness-panel inspection
The side of the glazing located away from the blast (inside the enclosure) shall be examined. It shall be
determined and noted whether or not any breakage or rupture of the inside surface has occurred. The witness
panels shall be carefully inspected for the presence of perforations and indents resulting from the blast. If
present, the location of perforations and indents shall be documented, with their height above the floor of the
witness area recorded.
7.4 Hazard rating
The hazard rating of the glazing or glazing system shall be in accordance with the rating criteria definitions as
given in Table 1 and Figure 1. The hazard rating that glazing or glazing systems receive is based upon the
severity of fragments generated during an air-blast test. The fragment severity is determined based upon the
number, size, effects and location of fragments that lie at, or behind, the original location observed during
post-test data gathering. Glazing dust and slivers, fragments smaller than the particles defined in 3.7 and their
effects are not taken into account for the ratings. For rating purposes only, the minimum area of the witness
panel defined in 6.6 shall be considered and no account shall be taken of perforations and indents of size less
than 3 mm in any direction (width, length and depth) or caused by particles classed as smaller than fragments.
Examples of minimum sizes of glass particles classed as fragments are provided in Annex D (informat
...