Reg.no. 2005/087037/23
P O Box 32422
GLENSTANTIA
0010
Phone: (012) 349 2929
Fax: (012 349 1519
Cell: 082 892 4565/083 654 9972
Our reference: FTC09/166
Conveyor Belt Technology Ltda.
Avda. Santa Maria 2670 Of. 305
Santiago - Chile
For attention: CBTECH
4 February 2010
Dear Sir
EVALUATION OF THE SMALL-SCALE FIRE PROPERTIES OF CONVEYOR
COMPONENT SAMPLES
1.
SAMPLE DESCRIPTION
A sample of material was delivered for evaluation of its small-scale fire properties.
The material is used to manufacture components used in the production of
conveyor roller assemblies, such as bearing housings and shells. Its suitability for
underground use in terms of fire safety was also assessed based on these results.
The sample delivered as a pipe section had a light green appearance but the
actual colour can reportedly vary to be orange or black; the pigment would have no
effect on the outcome of these tests.
2.
TEST METHODS AND RESULTS
2.1 Toxicity of combustion gases (NES 713)
Approximately one gram of the sample was burned in a chamber with a volume of
1 m3. The concentrations of certain specified gases were determined by means of
colorimetric (Dräger) tubes. These concentrations were then used to calculate the
quantities of gases given off by burning 100 g of material in a cubic metre of air.
The toxicity index is calculated from the summation of the ratios of these
concentrations to the concentrations causing fatality to man after a 30-minute
exposure time. Gases to be determined and their fatality limits are:
Gas
Conc. (ppm)
Gas
Conc. (ppm)
Carbon Dioxide
100000
Nitrous Oxides
250
Carbon Monoxide
4000
Hydrogen Cyanide
150
Formaldehyde
500
Acrylonitrile
400
Hydrogen Fluoride
100
Ammonia
750
Hydrogen Chloride
500
Sulphur Dioxide
400
Hydrogen Bromide
150
Hydrogen Sulphide
750
Phenol
250
Phosgene
25
The following results were obtained:
Gas detected
Conc. of gas per 100 g of
material consumed (ppm)
Toxicity Index
Carbon Dioxide
90 000
0.9
Carbon Monoxide
3 500
0.875
Nitrous oxides
100
0.4
Hydrogen Cyanide
traces
-
Total Toxicity Index: 2.175
2.2 Small-scale fire propagation properties (SANS 10177 Part 9)
The 1000 mm long pipe with 160 mm OD and wall thickness of 10 mm was
suspended in a 300 mm x 300 mm x 2.1 m high metal chimney along its length. A
Bunsen burner with a flame length of 60 mm and a temperature of 1 100 ˚C was
applied at an angle of 45˚ 100mm below to the bottom edge of the sample for a
period of 10 minutes.
The temperature near the top of the chimney was recorded with a single K-type
thermocouple. This temperature was used to determine the heat contribution of
2
the test specimen in comparison to the plot obtained from a “blank” run. Other
observations related to the presence of flaming droplets, the propensity to selfextinguish upon removal of the burner and rate of flame spread along the height of
the specimen were also noted.
The following results were obtained during this evaluation:
•
•
•
•
•
•
•
Time to ignition: immediate
Time to burn over entire length: did not burn over full length
A minor quantity of molten burning fragments were noted during the test – all
the material on the floor self-extinguished after 8 minutes
Material did not burn upon sporadic removal of burner at 12 seconds and
24 seconds
Length of heat damage on sample: 120 mm
Heat contribution over 10-minute test duration: 0 ºC /min
Maximum temperature in chimney (at any time during test): 0 ºC above
ambient (calibration temperature)
The material ignited and burned slowly throughout the test period. Selfextinguishment occurred upon removal of the burner after the completion of the
10-minute test period
3.
DISCUSSION OF RESULTS
The toxicity level of the combustion gases released by the sample is within
acceptable limits.
The small-scale fire propagation test on the sample revealed that the material
would only burn when under the influence of an external fire source.
4.
CONCLUSION
Although the material is combustible by definition it does display a propensity to
self-extinguish and does therefore not constitute a particular fire hazard in itself.
The toxicity index of the gases released upon combustion of the material is within
acceptable limits (below 5.0).
Care should however be taken during the underground transport, handling and
storage of this product as it would present a more significant fire risk under those
conditions, where larger quantities of combustible material would be present in a
specific area. All activities involving this product should be managed in
accordance with the dictates of sound fire management principles.
3
The fact that this type of material is used in a conveyor system should also be
recognised. The rollers themselves represent a relatively minor component within
a rubber conveyor system in terms of combustible mass, and the ignition and fire
propagation properties of the rubber conveyor will dominate as far as the fire risk
of the overall system is concerned. In general, newer generation PVC conveyor
belts are not particularly ignitable and tend not to support fire propagation. The
use of a roller system in association with such a belt will not have a negative
impact on the overall fire risk of the belting system.
Yours faithfully
K van Dyk
Fire Technology & Consulting Services
T/a FIRELAB
4