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IS0
I N T ER NAT1 O N AL OR GAN I Z AT1 O N FOR S TA N DAR D I ZAT I O N
IS0 RECOMMENDATION
R 543
DEFINITION AND MARKING OF SAFETY FILM
FOR MOTION-PICTURE USES
1st EDITION
December 1966
COPYRIGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 543, DeJnition and Marking of Safety Film for Motion-
Picture Uses, was drawn up by Technical Committee ISO/TC 36, Cinematography, the Secretariat
of which is held by the United States of America Standards Institute (USASI).
Work on this question by the Technical Committee began in 1948 and led, in 1961, to the
adoption of a Draft IS0 Recommendation.
In November 1963, this Draft IS0 Recommendation (No 637) replacing Draft IS0
Recommendation No. 83 was circulated to all the IS0 Member Bodies for enquiry. It was
approved, subject to a few modifications of an editorial nature, by the following Member Bodies:
Belgium France Romania
Brazil Germany Spain
Bulgaria Greece Sweden
Hungary Switzerland
Canada
Chile Italy United Kingdom
Colombia Japan U.S.A.
Czechoslovakia Netherlands U.S.S.R.
Denmark New Zealand
No Member Body opposed the approval of the Draft.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0
Council which decided, in December 1966, to accept it as an IS0 RECOMMENDATION.
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ISOlR 543 - 1966 (E) II
IS0 Recommendation R 543 Decem ber 1966
DEFINITION AND MARKING OF SAFETY FILM
FOR MOTION-PICTURE USES
1. SCOPE
The specifications contained in this IS0 Recommendation apply to both unprocessed and pro-
cessed film * and to film having magnetic coatings or stripes. Motion-picture films are classified
as safety films if they are difficult to ignite, slow burning and low in nitrate nitrogen content.
2. IGNITION TIME
2.1 Definition
Motion-picture films are classified as difficult to ignite when the ignition time is greater than
10 min at the temperature specified below.
2.2 Method of measurement
The ignition time of motion-picture films is measured as follows :
2.2.1 Preparation ofrest sample. A sample 35 mm (1.38 in) long and 8 mm (0.32 in) wide should
be cut from the film to be tested. The sample should be free of perforations as far as is
practicable. The sample should be conditioned for at least 4 h at a temperature of
20 f 2 "C and a relative humidity of 50 f 5 %.
2.2.2 Procedure. The test should be made in an electric resistance oven, the interior of which
is in the form of a vertical cylinder (preferably with a rounded bottom), having a
diameter of 70 mm (23/4 in) and a mean height of 70 mm. The top of the oven should
be closed by means of a closely overlapping lid having two holes of 7 mm (0.28 in) and
of 15 mm (0.59 in) respectively, the centres being at a distance of about 15 mm from each
other. A thermocouple should be introduced through the smaller opening, the connecting
wires having a porcelain coating fitted tightly into the hole. Alternatively, the temperature
in the cylinder may be measured by means of a mercury thermometer protected from
rising heat by means of a cork disk lying a little above the lid.
2.2.2.1 Temperature oftests. The oven should be brought to, and maintained at, a temperature
of 300 f 3 "C (572 f 5 OF). When this temperature is reached, the sample attached
to a thin U-shaped wire hook should be introduced through the larger opening. The
thermocouple (or the thermometer) and the sample should be fixed in such a way that
the thermojunction (or the mercury bulb) and the centre of the sample are at an
equal depth of about 35 mm (1.38 in).
2.2.2.2 Preparation for tests. Between tests, the oven should be thoroughly aired.
2.2.3 Expression of results. The time interval from the insertion of the sample to the ignition
of the sample is recorded as the ignition time.
* Normally, unprocessed and processed films have the same safety characteristics, so that either may be tested for con-
formance to these specifications. In case of doubt, both unprocessed and processed films should be tested.
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ISOlR 543 - 1966 (E)
3. BURNING TLME
The burning time may be determined by either of the two methods specified.
3.1 First method of measurement
3.1.1 Principle of method. Motion-picture films having a thickness equal to or greater than
0.08 mm (0.0032 in) are classified as slow burning when the burning time is not less than
45 s. Motion-picture films having a thickness less than 0.08 mm (0.0032 in) are
classified as slow burning when the burning time is not less than 30 s.
3.1.2 Preparation of test samples. Three samples each 40cm (15.8 in) long and 35mm (1.38 in)
wide should be cut from the film to be tested. If only films narrower than 35 mm are
available, samples 40 cm (1 5.8 in) long and their full width may be tested. * Each sample
should be marked at a point 5 cm (2 in) from each end. If not already perforated, the
sample should be perforated with holes 3 mm (0.12 in) in diameter along both edges.
Perforations should be at intervals of not more than 20 mm (0.8 in). The sample should
be conditioned for at least 4 h at a temperature of 20 f 2 "C and a relative humidity
of 50 f 5 %. **
3.1.3 Procedure. The burning time of motion-picture films is measured as follows: a wire having
a diameter of not more than 0.5 mm (0.02 in) should be threaded through the perforations
on one side so that the sample is supported at points not more than 20 mm (0.8 in) apart.
With the wire stretched horizontally and the sample hanging vertically from it, the bottom
corner of one end should be ignited.
3.1.4. Test conditions. The test should be made in a room free from draughts. At least three
tests should be made.
3.1.5 Expression of results. The time which elapses from the moment the flame reaches the
first mark until it reaches the second mark should be recorded as the burning time. If the
sample does not ignite or if the flame does not reach the second mark, the film should
be classified as slow burning.
3.2 Alternative method of measurement
Motion-picture films are classified as slow burning if each of six
3.2.1 Principle of method.
samples fulfils one of the following conditions:
(a) the sample fails to burn beyond the specified mark;
(b) a period of not less than 120 s elapses from the time of ignition of the alcohol to the
time at which the flame reaches the specified mark.
3.2.2 Preparation of test samples. The test samples should be taken from either end or bothends
of the continuous length of film which is to be examined. For the purpose of the burning
test, six samples should be taken, each of a length of 533 mm (21 in) for both 35 mm and
16 mm film. The samples should be tested in the condition in which they are cut from the
continuous length without removal of protective or magnetic coatings, stripes or emulsion.
The samples should be conditioned for at least 4 h at a temperature of 20 f 2 "C
and a relative humidity of 50 f 5 %. **
NOTE. - It is important to observe that the whole of the samples for both methods of test should be
taken from the same continuous length, and that if the roll of film to be examined contains splices, then
each individual continuous length should be examined separately. The object of taking six samples for
the burning test is to obtain accurate results in the test and not to confirm the homogeneity of the film;
the samples may therefore be taken consecutively.
* Motion-picture films, when tested by this method, have similar flame propagation characteristics and about the same
burning times, regardless of whether the width of the sample tested is 16 mm or 35 mm.
** Experience has shown that safety film will meet the requirements for burning time when conditioned to any relative
humidity in the range of 10 to 70 %. The more stringent range of 50 % 5 % of this test method is specified in the
interest of obtaining strictly comparable results. Likewise, the 4 h conditioning time is not critical and may be reduced
to 1 h minimum if the urgency of the test makes this desirable.
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I
ISO/R 543 - 1966 (E)
3.2.3 Apparatus for 35 mmfifilm. Samples of 35 mm film should be tested on an apparatus
:
complying with the following requirements
The apparatus consists essentially of two semicircular supports, each L-shaped in cross-
section, curved to a radius of 178 mm (7 in), spaced apart at a suitable distance for
supporting the film within the angles, and structurally completed by a base-plate tying
the two ends together (see Fig. 1).
<-
!
Spacer
Mark e
Supports i
\\\\ MorkA
see fig. 3 and 8
~____---
~~
L25.4 mm
Bose-plate j (I in)
Iy-py-pq
178mm 229rnm
FIG. 1. - General arrangement of apparatus for flammability tesi of safety film
The two supports should be made of mild steel, about 1.2 mm (0.05 in) thick, and should
be spaced so that their inner edges are 25.4 mm (1 in) apart, the spacers being of wire
shaped as shown in Figure 2.
film sarnpk
Steel strips
4.8 mm x O. I2 mrn
(31,B in x 0.005 in)
h
Steel ongle approx 1.2 mm
(0.05 in) thick
steel wire
FIG. 2. - Section through supports showing wire spacers for 35 mm film apparatus
The film sample should be held in position over the semicircular supports by two strips
of spring steel, 4.8 mm wide by 0.12 mm thick (3/~6 in by 0.005 in), each of which is riveted
at one end to a support (see Fig. 3). The other ends of the two steel strips are connected,
at the appropriate distance apart, by a thin steel crossbar (see Fig. 4). At the igniting
end there should be, between the supports, a flat platform of heat insulating material
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ISOlR 543 - 1966 (E)
(mica, asbestos, etc.) on which a small alcohol cup may be placed. The upper surface
of the platform should be 25 mm (about 1 in) above the base-plate and should be 20 mm
(0.8 in) long by 10 mm (0.4 in) wide.
Steel strips
(bent back for
insertion of film)
\ 5mm
Mark A
Support for
(heat insulating
E material)
!I;
E2
FIG. 3. - Detail of end X for 35 mm film apparatus
4
Steel cross bar
4
FIG. 4. - Detail of end Y for 35 mm film apparatus
The apparatus for 16 mm film is similar in general design.
The alcohol cup should be of copper and should have the dimensions shown in Figure 5.
3 mm (0.12 in)
(int)
10 mm (0.4 in)
(int)
(0.8 in)
{int)
FIG. 5. - Alcohol cup for 35 mm film apparatus
One curved support should carry two register lines or marks, as shown in Figure 1, which
should be clearly visible when the film sample is in position, and which should be marked
A and B respectively.
The mark A should be 38 mm (1.5 in) above the base-plate at the igniting end. The
mark B should represent the position which would be occupied by the end of a piece of film
457 mm (18 in) long, whose other end coincides with the mark A.
3.2.4 Procedure for 35 mmfilm. The 533 mm (21 in) film sample should be placed in the trough
formed by the two L-section supports, with its end in line with the mark A. The steel
strips are drawn over and are held by a small spring which clips on to the crossbar which
joins them at their free end (see Fig. 4). Thus the film is securely held by a narrow portion
at each side and the centre portion of approximately 25 mm (about 1 in) of the film is in
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1
ISOlR 543 - 1966 (E)
free air. If the sample to be tested is a coated film, the sample should be placed coating
upwards. The copper cup should be placed on the platform centrally below the film;
0.3 ml of alcohol (not less than 95 %) should be placed in it and ignited.
3.2.5 Apparatus for 16 mm$lm. The apparatus is similar in general form to that specified above
for the testing of 35 mm film. The circular supports are curved to a radius of 229 mm
(9 in). They should be made of mild steel about 0.9 mm (0.036 in) thick, formed to the
dimensions shown in Figure 7, and should be spaced so that their i
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