ISO 16934:2007

INTERNATIONAL ISO
STANDARD 16934
First edition
2007-07-01

Glass in building — Explosion-resistant
security glazing — Test and classification
by shock-tube loading
Verre dans la construction — Vitrages de sécurité résistant à une
explosion — Essai et classification par charge d'air envoyée d'un tube




Reference number
ISO 16934:2007(E)
©
ISO 2007

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ISO 16934:2007(E)
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ISO 16934:2007(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Classification and hazard rating . 4
5 Test specimens . 4
6 Apparatus and equipment preparation. 5
7 Test procedure and requirements. 7
8 Performance requirements . 9
9 Classification of explosion-resistant glazing . 11
10 Test report and test-report summary. 13
11 Precision and bias . 15
Annex A (normative) Blast parameters and derivation. 16
Annex B (informative) Blast shock-wave characteristics . 18
Annex C (informative) Equivalent threat levels. 19
Annex D (informative) Fragment definitions and criteria comparisons with other standards. 20
Bibliography . 21

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ISO 16934:2007(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 16934 was prepared by Technical Committee ISO/TC 160, Glass in building, Subcommittee SC 2, Use
considerations.

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ISO 16934:2007(E)
Introduction
This International Standard provides a method for carrying out tests simulating high-explosive blasts in order
to assess and classify the response of glazing to the overpressure and impulse characteristics of blast. This
International Standard provides criteria for rating the level of damage to glazing from which can be assessed
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.
A shock tube is a facility which simulates explosive blast waves to load test specimens with consistency,
control and repeatability. Shock-tube tests provide an economic means to simulate relatively long-duration
blast shock waves representing the effects of large explosive devices at some distance. The results can be
assessed against broadly comparable arena tests.
Structural response to air-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.

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INTERNATIONAL STANDARD ISO 16934:2007(E)

Glass in building — Explosion-resistant security glazing — Test
and classification by shock-tube loading
1 Scope
This International Standard specifies a shock tube test method and classification requirements for explosion-
pressure-resistant glazing, including glazing fabricated from glass, plastic, glass-clad plastics, laminated glass,
glass/plastic glazing materials, and film-backed glass. This International Standard provides a structured
procedure to determine the blast resistance and the hazard rating of glazing and glazing systems. This
International Standard sets out procedures to classify such security glazing sheet materials by means of tests
on specimens of a standard size in a standard frame for the purpose of comparing their relative explosion
resistance and hazard rating.
The procedures and test method can also be used to test, but not classify, glazing systems where the sheet
infill is incorporated into frames purposely designed as complete products of appropriate size for installation
into buildings. This International Standard applies a method of test and classifications against blast waves
generated in a shock tube facility to simulate high-explosive detonations of approximately 30 kg to 2 500 kg of
trinitrotoluene (TNT) at distances from about 35 m to 50 m. The classifications approximately represent the
reflected pressures and impulses that are experienced by these equivalent threat levels on the face of a large
building facade positioned perpendicular to the path of the blast waves.
Classification is defined in terms of both blast shock-wave characteristics, expressed in terms of peak
reflected pressure, impulse, positive phase duration and wave-form parameter (decay coefficient), and rating
criteria, expressed in terms of degrees of glazing damage and fragment impact hazard. Classifications and
ratings are assigned based upon the performance of the glazing and are specific to the blast characteristics
under which the test has taken 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)
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ISO 16934:2007(E)
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
air temperature around the test specimen measured within 30 min of the test
3.3
attack face
face of the test specimen intended to face the explosion source
3.4
blast shock wave
test pressure wave impinging on the attack face of the test specimen (defined in the terms below)
NOTE The pressure recorded and referred to shall be the peak positive pressure experienced by the test specimen
positioned at the end of the shock tube. This is typically a reflected pressure.
3.5
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 in-fill pulling away from the rebate sufficiently to result in a
visible gap that exposes the edge of the sheet.
3.6
cartridge paper
2
thick white paper for pencil and ink drawings, typically about 130 g/m
3.7
fragment
any particle with a united dimension of 25 mm (1 in) or greater as defined in Clause 8
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
fragment collecting mat or surface
clean, smooth surface at nominal floor level in the protected area suitable for observing and collecting ejected
fragments
NOTE It shall extend over an area of width and of depth from the rear face to the witness panel as defined for a
witness area in Clause 6 at a level at least 0,5 m but not exceeding 1,0 m below the bottom edge of the test specimen
when that is representative of a typical window. The level of the mat may be adjusted to correspond with the intended level
of floor in relation to the position of a non-standard test specimen in the building as defined in Clause 8.
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ISO 16934:2007(E)
3.9
glazing
glass or plastics glazing sheet material, including glass/plastic combinations
NOTE Glazing may also refer to a fenestration assembly in which glass or plastic sheet infill is set in and is complete
with a framing system for installation into a building.
3.10
impulse
I
pos
area under the positive phase of the pressure-time trace
NOTE 1 This is usually obtained by automatic electronic numerical integration of the gauge readings. This is also
sometimes called the specific positive phase impulse. If sharp irregularities in the recorded trace result in non-
representative transient dips into negative pressure or the negative phase is absent, the positive phase impulse should be
calculated over the period of the mean pressure-time trace duration.
NOTE 2 Different subscripts may be used for the blast parameters, as described in Annex A. For example, the positive
phase impulse, I , may be denoted I where it denotes the classification impulse or I where it denotes the impulse
pos c t
calculated from the measured test values.
3.11
peak pressure
P
max
initial peak positive reflected pressure above ambient atmospheric pressure experienced at the attack surface
of the test specimen following an instantaneous rise at the time of arrival of the shock front
NOTE If the measured pressure-time trace has sharp spikes or 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
max
relevance is the resulting smoothed value at the time of arrival.
3.12
positive phase duration
t
pos
duration of the positive phase of the mean pressure-time trace
NOTE The mean pressure-time trace should have positive phase duration, waveform and peak pressure such that
the area under this curve equals the positive phase impulse obtained by direct integration of the original recorded trace.
The duration can normally be derived by reference to the time of the peak of the impulse-time curve.
3.13
pressure-time wave trace
pressure values plotted against time
NOTE The instantaneous rise at the shock front to the peak positive pressure, P , is followed by a non-linear decay
max
to ambient pressure over a time called the positive phase duration. The shape of the decay curve may be modelled by an
exponential decay curve having a decay coefficient, A, also known as a waveform parameter. In a free-field blast, a period
of negative pressure then follows for a period of time before returning to ambient. Within the confines of a shock tube, this
period of negative pressure is sometimes absent or reduced in value.
3.14
protected area
area on the side of the test specimen away from the source of the shock wave
3.15
rear face
protected area side of the test specimen opposite to the attack face
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ISO 16934:2007(E)
3.16
reflected pressure
pressure experienced by a surface which obstructs the flow of a blast wave
NOTE The shock wave moving through the air impacts the test specimen and is “reflected”, producing a pressure on
the surface having a value higher than would have occurred within an unobstructed flow or on the side of a target parallel
to the direction of travel of the pressure wave.
3.17
test specimen
sample of glazing submitted for test
3.18
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 Clause 6.
3.19
witness panel perforations
any holes in the surface of the witness panel caused by impact of any material as a result of the blast
NOTE The number, size and depth of penetration of such perforations can be used as a guide to the injury potential
of material detached from the test specimen.
3.20
witness panel indents
any detectable deformation of the surface of the witness panel caused by impact of any material as a result of
the blast
4 Classification and hazard rating
A hazard rating is applied to glazing based on its performance under the classification blast conditions chosen
for the test. The rating is specific only to those blast conditions. Hazard rating criteria are defined in Table 1.
Classifications are assigned according to the blast intensity measured in terms of pressure, impulse and
duration. Each classification code is one of a series having defined blast values as listed in Table 2.
5 Test specimens
Test specimens may be submitted in two forms, as described in 5.1 and 5.2.
5.1 Glazing sheet
Glazing sheet submitted for test in a standard configuration and mounted in a standard frame in order to
demonstrate or prove performance in relation to other sheet materials. For the purpose of obtaining a
classification of the sheet material in accordance with this International Standard, a minimum of three test
specimens, each (1 100 ± 5) mm × (900 ± 5) mm, shall be tested and shall be clearly identified by type and
with an indication of the attack face. One additional specimen shall be provided for pre-test measurements.
The test pieces shall conform to the specification of the manufacturer and shall be representative of normal
production quality. They shall be arrissed for ease of handling.
For the purposes of obtaining a test assessment, a single glazing sheet test specimen may be supplied. The
results cannot be used to classify the glazing.
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ISO 16934:2007(E)
5.2 Fenestration assemblies
This is glazing submitted complete with a framing system, fabricated and of a size typical for installation in a
building and made up as a test specimen appropriate for mounting in the test apparatus.
The blast resistance of a fenestration assembly may be assessed by being tested and rated in accordance
with the provisions of this International Standard. The test report and test report summary shall state that the
results are applicable only to the product as tested. The number of assemblies tested shall be stated and shall
be agreed prior to test. The results cannot be used to classify the fenestration assembly or the glazing infill
independently as a sheet material.
5.3 Multiple specimens — Probability of achieving blast resistance
The air-blast resistance capacity of glazing does not imply that a particular specimen will resist 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.
5.4 Handling and storage
The test specimens shall be handled and stored in compliance with the manufacturer’s instructions.
5.5 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
the manufacturer to assure proper installation in the test frame. A number shall be assigned to each test
specimen and marked accordingly.
5.6 Measurements
Thickness measurements of the glazing material shall be made at each corner, 25 mm from each edge and
recorded. If the glazing sheet specimens are supplied already mounted in a frame and if four test specimens
are supplied, 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. If necessary for verification, the fourth specimen shall be
disassembled. Measurements and records shall be made of the bolts, screws or other devices used for fixing
the test specimen to the test specimen support and those used to mount the support onto the shock tube.
5.7 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 Apparatus and equipment preparation
6.1 Shock tube — Pressure-generating device
The shock tube shall be a device capable of reproducing the required plane shock wave to simulate the
effects from a high-explosive source and applying the blast load to a test specimen. The shock tube shall be
capable of reproducing the shock wave consistently from test to test within a 0 % to + 15 % accuracy of a
desired value for both the peak pressure and the impulse.
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ISO 16934:2007(E)
6.2 Test frame
The test specimen shall be supported by a rigid test frame through which the test specimen may be securely
attached to the shock tube in a vertical position via a reaction structure of substantial construction. The whole
assembly shall be sufficiently rigid to withstand repeated application of test loads without permanent distortion
and without imparting deformations to the test specimen.
The reaction structure shall form or be integral with a rigid shield around the edges of the test specimen that
meets the walls of the shock tube and prevents the escape of blast pressure other than through deformation
or design intention of the test specimen.
6.3 Protected-area platform and fragment-collecting mat
A platform shall be provided in the protected area between the test specimen and the witness panel at a
height representing floor level as defined in Clause 8. The platform shall have a surface, or be provided with a
mat, suitable for collecting fragments in the witness area for the purpose of assessing hazard ratings. The
witness area shall be of a width sufficient to capture all fragments or be provided with sides spaced apart not
less than the width of the witness panel, as defined in 6.5, to channel and control the spread of fragments.
The sides may be of transparent material to aid recording and photography.
6.4 Test frame and reaction structure
When glazing sheet material is to be classified, the following test frame and reaction structure requirements
shall apply.
a) The test specimens shall each be mounted in the test frame, supported along the full length of all four
edges so as to achieve a vision size of (1 000 ± 5) mm × (800 ± 5) mm.
b) The test frame shall be fixed securely on all four sides in a vertical position to the reaction structure. The
test frame shall be provided with clamping plates to hold the glazing in position and means for producing
uniform clamping of the glazing.
NOTE Bolt or clamping device spacing of not more than 100 mm is recommended around the perimeter of each
specimen.
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 standard sheet glazing test specimen shall have an edge capture of not less than 45 mm on all
edges.
⎯ Each standard sheet glazing test specimen shall be separated from the 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, the glazing shall be seated on rubber strips, 4 mm thick, of hardness
(50 ± 10) IRHD in accordance with ISO 48:1994 and of a width equal to the full thickness of the test
specimen.
⎯ All four edges of each standard sheet glazing test specimen shall be uniformly clamped with a
2
clamping pressure of 140 ± 30 kN/m .
NOTE The clamping pressure can have a significant effect on the test results.
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ISO 16934:2007(E)
d) If the glazing is supplied in its own unique frame or in the form of 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 above the fragment-collecting mat appropriate to the manner in which they will be mounted in the
field.
⎯ The attack surface of each test specimen shall be aligned in a plane positioned in relation to the
attack surface of the test frame and reaction structure such that the blast values experienced by the
test specimen are accurately measured or computed.
⎯ It is recommended that the attack surface of the test specimen be not more than 25 mm behind the
surface of the test frame and that the reaction structure be inside the shock tube to minimize
entrapment and enhancement of the blast effects.
⎯ Each test specimen shall be placed normal to the direction of the explosive shock wave (or normal to
the axis of the shock tube) with an accuracy of + 2° in any orientation.
6.5 Witness panel
A witness panel shall be mounted (3 000 + 150) mm behind each test piece, parallel to the plane of the test
specimen. The witness panel shall consist of sheets of non-ductile, foam insulation board, of material
3
equivalent to 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. The witness panel shall have a width of
not less than 2,0 m if contained within sides as defined in 6.3, or, if not so contained, a width of at least 2,4 m,
(i.e. 1,2 m either side of the centre axis of the shock tube, or the width of the test specimen, if greater) and at
a height extending from the level of the collecting mat to at least 200 mm above the top of the test specimen.
In order to aid the recording of the damage and reduce waste, the board may contain a removable face layer
at least 12 mm thick and the witness panel may be faced with contiguous sheets of aluminium foil of thickness
2 2
not more than 0,025 mm or cartridge paper of weight between 100 g/m and 150 g/m .
6.6 Pressure-measuring equipment
The pressure-measuring equipment shall permit the determination of the magnitude, above ambient pressures,
and time development of the reflected shock wave impinging on the test specimen. Calibration records shall
be maintained that demonstrate the equipment can measure pressure with an accuracy of ± 5 % with a rise-
time sensitivity response to peak pressure of 10 µs. In order to perform this task, the equipment shall record
the pressure at intervals not greater than 0,01 ms, i.e. a sampling rate of 100 000 samples per second,
starting before the shock wave reaches the test specimen and for a length of time at least 10 times the
duration of the positive phase from the time of arrival at the test specimen. The pressure-time history shall be
recorded by means of at least two blast gauges (pressure transducers). The blast pressure gauges shall be
positioned to enable accurate determination of the reflected pressure-time values (above ambient) at the
centre of the test specimen. Gauges at the test-mounting location shall be calibrated during special pre-tests
against gauges set in the centre of rigid blanking plates fixed in the test specimen support. The calibration
records shall either demonstrate that the readings are identical in the two locations or provide means of
adjusting the test-location gauge readings to values that accurately represent the reflected pressure-time
values at the centre of the test specimen.
7 Test procedure and requirements
7.1 Pre-test procedure
Determine the required reflected pressure and impulse from Table 2 according to the level of explosion
resistance required.
Mount the test specimen in the frame and position in the shock tube. Inspect for correct installation and
tightness of fixings, and record the inspection results.
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