3 Performance requirements
3.01 Photometric requirements
The minimum coefficient of retro-reflection (R') when
illuminated by CIE Standard illuminant A (colour temperature 2856 K) should be as
specified in table 3.1 for the retro-reflective areas of new and dry material when
tested as described in section 4.2. The brightness of the retro-reflective
material, when tested as described in section 4.9, should be not less than 80% of
the table 3.1 values.
3.02 Accelerated weathering
Applied to an aluminium test panel, the material should show
no significant discoloration, cracking, blistering or dimensional change, and
should have not less than 80% of the specified minimum reflective intensity values
in table 3.1, when tested as described in section 4.10.
3.03 Seawater immersion
Where tested as described in section 4.3, the material
should show no evidence of blistering, delamination or subsurface corrosion. The
material should show no evidence of "whitening" and its retro-reflective intensity
should not be reduced below the retro-reflective values in table 3.1 except within
5 mm of each side of the required cuts.
3.04 Flexibility
There should be no cracking of the retro-reflective
material, after conditioning for 4 hours at -30°C, when bent around a 3.2 mm
mandrel and tested as described in section 4.4.
3.05 Tensile strength
Tensile strength N (newton) per 25 mm width:
material without support
>16 N material with support
>330N longitudinal for mechanical
fastening >200N transverse
when tested as described in section 4.5.
3.06 Adhesive strength
For adhesive-backed material only. The adhesive strength
should be not less than 16 N per 25 mm width when tested as described in section
4.6.
3.07 Blocking
The material should show no blocking when tested as
described in section 4.7
3.08 Salt spray resistance
The material should show no evidence of corrosion or
degradation that would impair its effectiveness or reduce the coefficient of
retro-reflection below the values in table 3.1 after exposure to a saline mist for
120 hours followed by cleaning with a dilute neutral detergent solution as
described in section 4.8.
3.09 Temperature resistance
The material should show no evidence of cracking,
distortion, or loss of coefficient of retro-reflection below the values in table
3.1 after exposure, in a dry atmosphere, for 24 hours to a temperature of 65±2°C
and subsequent exposure for 24 hours to a temperature of - 30±2°C.
3.10 Fungus resistance
Applied to an aluminium test panel, the material should not
support fungus growth, should show no loss of coefficient of retro-reflection
below the levels in table 3.1, and should not be removable from the test panel
without damage, when tested as described in section 4.11.
3.11 Abrasion resistance
Applied to an aluminium test panel, the material should not
have less than 50% of the specified minimum reflective intensity values in table
3.1, when tested as described in section 4.12.
3.12 Soil resistance and cleanability
Applied to an aluminium test panel, the material should not
have any significant visible damage or permanent soiling when tested as described
in section 4.13.
4 Test Method and interpretation of test results
4.01 Test conditions and number of samples
Test specimens should be conditioned for 24 hours at a
temperature of 23±1°C and 50±5% relative humidity before being tested. All test
results should be interpreted as the average obtained from testing at least three
specimens.
4.02 Photometric performance
The photometric performance should be measured using the
general procedure recommended by CIE Report No.54, 1982. The sample dimensions
should be 150 mm by 150 mm. Entrance and observation angles should be as specified
in table 3.1. Readings shall be taken at not greater than 30° increments as the
observation half-plane is rotated about the reference axis (i.e. at rotation
angles ( ) of 0°, 30°, 60°, 90°, 120°, 150° and 180°). Each measured value should
be the average of the readings for all of the required samples.
4.03 Seawater immersion
Prepare a 75 mm × 150 mm test panel.
(A) material without support:
After removing protective liner paper, apply
specimens to a clean aluminium panel surface, using a hand-roller for
application.
(B) material with
support for mechanical fastening:
Tape edges of test specimens to a clean aluminium
panel
The retro-reflective material on
each test panel is cut with a sharp knife from each corner diagonally opposite
so that an "X" is formed. The cuts must be made completely through the
material to the metal panel.
Immerse the
test panels to half length in a 4% (by weight) salt water solution (4 g NaCl
dissolved in 96 ml distilled water) at 25°, using a glass beaker covered by a
glass plate. After a 16-hour immersion period, remove the panels from the
beaker, rinse salt deposits from the panels, and examine the sample following
a 10-minute recovery period and again after 4 hours for compliance with the
requirements described in section 3.3.
4.04 Flexibility
Condition test specimen for 4 hours in a cold chamber at
-30°C. A 3.2 mm mandrel should be conditioned at the same temperature. The
sample should be bent over the free-standing mandrel, gently applying gloved
finger pressure.
For material without support,
remove protective liner and talc the adhesive to prevent sticking.
4.05 Tensile strength
Prepare three test samples 25 mm in width and 150 mm in
length. Insert samples into the grips or jaws of the testing machine so that the
load is distributed evenly across the width of the samples and the initial test
length is 100 mm. Determine tensile strength at a speed of 300 mm per minute.
Record average tensile strength at break in newtons per 25 mm width for all three
test samples. For material without support, remove protective liner paper before
inserting samples in the tensile tester.
4.06 Adhesive strength (for material without support only)
Prepare three test samples 25 mm in width and 200 mm in
length for each type of surface to which the material is to be applied. Remove
protective liner paper for 80 mm in length and apply test specimens to the test
surfaces. Test surfaces should be aluminium, GRP, each type of lifejacket and
lifebuoy that the material is to be used on, and inflatable liferaft buoyancy tube
material. Test surfaces should be 50 mm in width, 90 mm in length, and of the
thickness normally used and should be properly cleaned by wiping the surface with
a suitable solvent.
Apply test specimens with
a solid brass roller, 80 mm in diameter and 40 mmin width covered with rubber
approximately 6 mm thick and having a hardness of 80±1 RHD and a total mass of
approximately 2 kg. Use three passes for roller application and allow to have a
120 mm free overlap strip to be used for inserting into the jaw clamp of the
testing instrument. One test panel should be immersed in distilled water in a
covered container for 16 hours before adhesive strength testing and the other test
panel should be immersed in salt water (4% NaCl by weight) in a covered container
for 16 hours before adhesive strength testing. (This test method is required only
for retro-reflective material that is designed for use with an adhesive. If a
particular test panel used in testing results in a test failure, the
retro-reflective material should not be approved for attachment to material of the
type used as the test panel). Peel back at an angle of 180 at a speed of 300 mm
per minute. Record adhesive strength in newtons per 25 mm width. Repeat the
adhesive strength tests on samples subjected to the weathering test in section
4.10.
4.07 Blocking
Stack two 100 mm × 100 mm pieces of material,
retro-reflective face to retro-reflective face, between two pieces of glass plate
3 mm thick of the same size as the samples and place in an air-circulating oven
operating at 65°C. Place an 18 kg weight centrally on the top glass plate,
and close the oven. After 8 hours, remove the test assembly from the oven, take
the retro-reflective material from between the plates, and cool for 5 minutes.
Separate the two pieces of retro-reflective material, and examine for evidence of
adhering or peeling of the surface.
4.08 Salt spray resistance
Prepare test specimens as described in section 4.3 (A) and
(B), respectively, and expose them to a salt spray chamber. The test should
consist of five periods of 22 hours' exposure each, separated by an interval of 2
hours during which samples are allowed to dry. The saline mist should be produced
by atomizing, at a temperature of 35±2°C, a saline solution obtained by
dissolving five parts of NaCl in 95 parts of water, containing not more than 0.2%
of impurities.
4.09 Photometric performance when wet
An unweathered 150 mm × 75 mm specimen should be mounted in
a vertical plane, with the 150 mm dimension oriented horizontally. Apply
sufficient water so that the entire specimen surface is covered by a continuous
moving film of water. Measure the coefficient of retro-reflection at 0.2°
observation angle and 5° entrance angle. An example of an appropriate test
apparatus is shown in figure 1.
4.10 Accelerated weathering
The photometric performance of the material should be
determined according to section 4.2 after the material has been exposed in a
sunshine carbon arc weatherometer for the following periods:
Type I material : 750 h
Type
II material : 1,500 h
After exposure, the
material should be examined for the requirements and characteristics in section
3.2.
4.11 Fungus resistance
Prepare three 75 mm × 75 mm test panels as described in
section 4.3 (A). Prepare three additional test panels as described in section
4.3(B), using non-rusting, non-staining clips or fasteners (in lieu of tape) to
hold the material flat. Expose the panels to mildew, using the soil burial method,
for a period of two weeks. The microbial activity of the soil should be verified
by exposing untreated cotton fabric of 400 g/m3 to 475 g/m3
to the soil bed for the first five days. The soil should be considered to be
satisfactory if this control sample loses not less than 50% of its original
tensile strength during this exposure.
At the
end of the exposure period, the test panels should be removed from the soil bed,
gently washed to remove soil, and wiped with a soft cloth wet with a 70% ethanol
solution. Condition the panels under standard conditions for 48 hours. Test the
photometric performance of the specimens as described in section 4.2 and, when
finished, attempt to remove the material from the test panel.
4.12 Abrasion resistance
An apparatus is required which should consist of an electric
motor mounted on a flat metal plate, and a mechanism through which the motor will
impart a reciprocating motion to a brush lengthwise across the full length of a
test panel clamped to the plate. Prepare one test panel 150 mm wide x 425 mm long,
as described in section 4.3 (A). Mount the panel firmly on the test apparatus and
place the brush on the panel.
The block of the
brush should be aluminium, 90 mm long × 40 mm wide and 12.5 mm thick. The brush
stock should be stiff, black, butt-cut Chinese hog bristle. There should be 60
holes on the block, 4 mm in diameter, solidly filled with bristle. The bristles
should extend 20 mm beyond the block to form an abrading surface as nearly planar
as possible. The total weight of the brush should be 450±15 g. Weights may be
fastened to the top of the brush to attain this weight.
Start the motor. The apparatus should be adjusted so that the
brush travels at a rate of 37±2 cycles (74±4 strokes) per minute. Remove the panel
after 1,000 brush strokes and wipe with a clean soft cloth. Test the photometric
performance of the material, as described in section 4.2.
4.13 Soil resistance and cleanability
Prepare a test panel 150 mm × 150 mm, as described in
section 4.3 (A). Soil the panel by applying a film, 90 mm wide × 0.075 mm thick,
of thoroughly mixed soiling medium across the middle of the test panel. The
soiling medium should consist of a mixture of 8 g carbon black, 60 g mineral oil
and 32 g odourless mineral spirits. Cover the soiled area for 24 hours with a
laboratory watch glass or similar device. Uncover the material and wipe off the
soiling medium with a clean, dry, soft cloth. Wet the material with mineral
spirits and wipe with a cloth soaked in mineral spirits. Wash with a 1% (by
weight) solution of detergent in warm water, rinse, and dry with a clean, soft,
dry cloth. Examine the sample for compliance with section 3.12.