BS EN ISO 9151:2016 download.Protective clothing against heat and flame — Determination of heat transmission on exposure to flame (ISO 9151 :2016).
3.3
heat transfer Index
HTI
<flame> mean time, tm, in whole seconds to achieve a temperature rise of (24 * 0,2) C when tested by the method described in BS EN ISO 9151 using a copper disc of mass (18 ± 0,05) g and incident heat flux of (80 ± 2) kW/mz
Note ito entry: Within (he context of this document, the heat transfer index refers to the heat transfer between a flame and the teat specimen. See fnnex A.
4 Principle
A horizontally oriented test specimen is restrained from moving and subjected to an Incident heat flux of (80 * 2) kW/m2 from the Flame of a gas burner placed beneath it. The beat passing through the specimen is measured by means of a small copper calorimeter on top of and In contact with the specimen. The time, in seconds, for the temperature in the calorimeter to rIse (24 ± 0.2) C Is rrcordecL The mean result for three test specimens is calculated as the heat transfer index (flame).
S Apparatus
5.1 General
The apparatus consists of:
— aMekergas burner;
— a copper disc calorimeter;
— a specimen support frame;
— a calorimeter location plate:
— a support stand;
— suitable measuring and recording equipment;
— a template.
5.2 Gas burner
A flat topped Melcer burner with a perforated top area of (38 ± 2) mm diameter and a jet suitable for propane gas shall be used, (See Annex H for possible sources.)
Commercial grade propane of 95% minimum purity shall be used with the flow being controlled by a fine control valve and flow meter. Alternatively, other gases may be used but such use shall be reported as part of the test report
5.3 Copper disc calorimeter and mounting block
Copper disc calonmeter. consisting of a disc of copper of minimum 99 6 purity, having a diameter of (40 t 0,05) mm and thickness 1.6 mm, and a mass of (18 ± 0,05) g. The disc shall be weighed before drilling and assembly.
The calorimeter shall be constructed as indicated In EjjtujjJ (method A) or Elgig2 (method B). Insulated copper-constantan thermocouple wire in accordance with IEC 60584-1 and IEC 60584-3, diameter 0.254mm ±002 mm shall be used. The constantan wire shall be either inserted into predrilled hole in the centre of the calorimeter and soldered in place with a minimum of solder (method A) or shall be soldered to the back face of the calorimeter as shown in Figure 2 (method B). The copper wire
6 PrecautIons
Perform the test in a hood or ventilated area to carry away the fumes. The test location should be surrounded by a volume of air sufficient not to be affected by any reduction of oxygen concentration. It may be necessary to turn off the exhaust or to shield the apparatus during the test so as not to disturb the flame. Air movement at the point of test shall be less than 0.2 rn/s at the commencement of the test oIeach specimen. The equipment becomes hot during testing and some test materials may melt or drip. Use protective gloves when handling hot oblects.
Keep combustible materials away from the burner. Ensure that the solvent used for cleaning the calorimeter is kept away from hot surfaces and naked flames.
7 Sampling
7.1 Specimen dimensions
The specimens shall have the dimensions 140 mm 140mm and shall be taken from points more than 50 mm from the edge of the pieces of the material, in an area free from defects. Composite specimens shall reproduce the arrangement in which the layers are used In practice. Alternatively, specimens may be taken from clothing samples according to a given product standard.
The specimen shall be marked out using the template (see .B).
7.2 Number of specimens
A minimum of three specimens shall be tested for each material or assembly of materials.
8 Conditioning and testing atmospheres
8.1 Conditioning atmosphere
Prior to testing, the specimens shall be conditioned for at least 24 h at a temperature of (20 ± 2) C and a relative humidity of (6S ± 5) %. If testing is not carried out immediately after conditioning, place the conditioned test specimens in a sealed container. Begin testing of each specimen within 3 mm of removing it from the conditioning atmosphere or sealed container.
8.2 TestIng atmosphere
Perform the tests in an atmosphere having a temperature of (23 ± 5) C and a relative humidity of 15 %
to 80 % and which is free from draughts (see cLau).
9 Test procedure
9.1 PreparatIon and calibration
9.1.1 PrelimInary procedures
Position the specimen support frame on the support stand so that the top surface of the support frame. on which the specimen is placed, is (SO ± 2) mm above the top face of the burner. It is suggested that a guide and stops he used to enable the burner to be positioned quickly with its axis in line with the centre of the specimen. Alternatively, a shutter system may be used (see ).
Place the burner to one side, activate and Ignite the gas supply, and allow a minimum of three minutes for flame stabilization.
9.3.2 Allow the test to continue until a temperature rise of at least 24 °C Is observed. Terminate the exposure by withdrawing the burner or, if fitted. replacing the shutter. Observe and note any changes in specimen appearance during and immediately following the test, e.g. shrinkage, scorching, charring, hole formation, glowing. meltmg. dripping. or as required in specific product standard.
9.3.3 Remove the calorimeter and clean oil any combustion products while it is still hot (see Clause 6). Cool to within ±2 C of ambient temperature (see U2).
lithe remaining deposit on the calorimeter is thick or uneven, lithe black coating has deteriorated, or if the copper is exposed, the calorimeter disc shall be cleaned (see Annex A) and repainted (see At least one calibration run (see 2J.2) shall be carried out with the recoated calorimeter before testing further specimens.
9.3.4 Record the time in seconds for a temperature rise in the calorimeter of 24 °C (see Annex C).
It is also possible to measure the time in seconds for a temperature rise of 12 C This measurement can be used to determine to what extent heat transfer is delayed or reduced. However, it should be stressed that the times measured have only a limited accuracy and do not necessarily relate to protection times under actual use conditions.
9.3.S Repeat the procedure with two more specimens. Calculate the heat transfer index as the mean of the times taken for a temperature rise of 24 DC. to the nearest whole number
10 Test report (see Annex C)
The test report shall contain the following particulars:
a) the name of test laboratory;
b) the date;
c) a reference to this document. Ic Iso 9151:2016;
d) the identification reference of the materials tested;
e) the description of the Lest materials and the arrangement in which they were tested, if possible details of generic names, mass per urnt area;
f) whether Method A or Method B calorimeter was used;
g) the gas used, ilother than the standard propane;
h) the time, temperatLire and humidity of conditioning,
i) the temperature and humidity in the testing laboratory;
j) the time In seconds for a 24 °C temperature rise for each specimen tested and the heat transfer index calculated according to 2.L
k) if requested, the time In seconds for a 12°C temperature rise for each specimen tested may also be reported;
l) the description of any changes in the specimens as per 2,jZ
m) the graph and calculation olcalibratlon shall be made available upon request.