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E.4 Smoke measurement system calibration

E.4.1 General

The smoke measurement system calibration shall be performed after set up, maintenance, repair or replacement of the smoke measurement system holder or other major components of the exhaust system and at least every six months. The calibration consists of three parts: an output stability check, an optical filter check for white light systems and a heptane burn.

E.4.2 Stability check

Perform the following steps with the measuring equipment operating and with the ignition source in position in the test chamber.

1. Set the volume flow of the exhaust to: V₂₉₈ = (1,00 ± 0,05) m³/s (as calculated according to A.1).

2. Start the time measurement (f = 0) and record the signal from the light receiver for a period of 30 min.

3. Determine the drift by use of a least squares fitting procedure to fit a straight line through the data points. The absolute value of the difference between reading at 0 min and at 30 min of this linear trend line represents the drift.

4. Determine the noise by computing the root-mean-square deviation (RMSD) around the linear trend line.

Criteria: Both noise and drift shall be less than 0,5 % of the start value.

E.4.3 Optical filter check for white light systems

The optical density measurement system shall be calibrated with at least five neutral density filters in the optical density range of 0,1 to 2,00. The optical density calculated with the measured light receiver signal shall be within ± 5 % or ± 0,01 of the theoretical value of the filters, whichever is the greater.

NOTE The optical density is defined as d_opl= log_l0(y-) where l₀ is the initial light intensity and I the light intensity with the filter in place.

A possible procedure to perform the calibration is given in F.4.

E.4.4 Smoke calibration by means of burning a flammable liquid

E.4.4.1 General

A calibration by burning a given mass of heptane in a tray shall be conducted in order to check the smoke measurement under conditions of high heat release.

E.4.4.2 Conditions to be used for burning heptane

1. Circular open steel fuel tray of internal diameter (350 ± 5) mm, with an internal wall height of (150 ± 5) mm and a wall thickness of (3,0 ± 0,5) mm.

2. Heptane of at least 99 % purity: (1 250 ± 10) g.

3. Water: (2 000 ± 10) g.

4. The tray, heptane and water shall be maintained within 2 °С of the ambient temperature for at least 4 h prior to conducting the calibration.

E.4.4.3 Procedure

Perform the following steps with the measuring equipment operating, with the airflow into the chamber set to (8 000 ± 400) l/min, the ladder removed from the chamber and the door closed during the burn:

1. Set the volume flow of the exhaust to: V298 = (1,00 ± 0,05) m³/s.

2. Record the temperature in the exhaust duct and the ambient temperature for at least 300 s. The temperature in the duct shall not differ by more than 4 °С from the ambient temperature.

3. Place the fuel tray such that its centre is on the burner centre line and (435 ± 20) mm from the rear wall of the chamber. The fuel tray shall be placed on a standard calcium silicate board with dimensions of 400 mm x 400 mm. Supports of 100 mm high shall raise the board above the floor of the chamber,

4. Weight the amount of water to be used and pour it into the fuel tray.

5. Start the time measurement and the automatic recording of data where the start time is defined as t - 0 s.

6. Weigh the amount of heptane to be used and pour it gently onto the water in the fuel tray at f = 240 s.

7. Ignite the liquid at t - 300 s.

NOTE Care should be taken when working with burning liquids.

8. After burning of the liquid ceases, wait for another 300 s.

9. Stop the automatic recording of data after this 300 s period.

E.4.4.4 Calculations

Calculate the following quantities:

1. the total smoke production TSP during the calibration test from the time of ignition until the end of data recording;

2. the TSP divided by the mass of heptane used.

E.4.4.5 Criteria

The following criteria shall be met:

1. at the end of the calibration test, the signal from the light receiver shall be within 1 % of its initial value

2. the ratio TSP divided by mass of heptane shall be within the range (110 ± 25) m²/1 000 g

NOTE Measurement of the HRR and calculation of the THR during the heptane smoke calibration test can give useful information on the performance of the system. The theoretical value of the THR (assuming complete combustion) is 44,6 MJ per 1 000 g of heptane assuming an E-value of 16,5 MJ/m³.Determine velocity
profile

No

Start troubleshooting and
repeat this or previous step

Perform HRR calibration with propane at level і

Determine correction

factor Cj

No

propane—x.

^calibrations performed?^

*T^Yes

Determine average
propane correction factor C_p

No

Start troubleshooting and
repeat this or previous step

No

Start troubleshooting and
repeat this or previous step

Perform methanol calibration

Determine correction factor for methanol as

Determine overall C
as average of and C_p

Determine commissioning factor k,
with correction factor C

Perform heptane calibration using factor k.

Use commissioning k_t factor for daily use

No

No

Figure E.1 - Overview of commissioning calibrations

Annex F
(informative)

Guidance for calibration procedures for specific measuring equipment

F.1 General procedures for separate pieces of equipment

This annex includes calibration procedures that satisfy the relevant performance based calibration requirement given in Annex E.

F.2 Gas analyser calibrations

F.2.1 Oxygen analyser adjustment

The oxygen analyser may be adjusted using the following procedure. An analyser adjusted according to this procedure is expected to meet the requirements of E.2.2.

1. For zeroing, feed the analyser with oxygen-free nitrogen gas, with the same flow rate and pressure as for sample gases. When the analyser reaches equilibrium, adjust the analyser output to (0,00 ±0,01) %.

2. For span calibration either dried ambient air or a specified gas with oxygen content of (21,0 ±0,1) % may be used. If ambient air is used for span calibration the exhaust system should be running at (1,00 ± 0,05) m³/s during the entire calibration. If “a specified gas” is used, the exhaust system is not needed. When the analyser reaches equilibrium, adjust the analyser output to (20,95 ± 0,01) % if dried air is used or to within 0,01 % of the actual oxygen content if the specified gas is used.

F.2.2 Carbon dioxide analyser adjustment

The carbon dioxide analyser may be adjusted using the following procedure. An analyser adjusted according to this procedure is expected to meet the requirements of E.2.4.

1. For zeroing, feed the analyser with carbon dioxide-free nitrogen gas, with the same flow rate and pressure as for sample gases. When the analyser reaches equilibrium, adjust the analyser output to (0,00 ±0,01) %.

2. For span calibration a specified gas with carbon dioxide content approximately 75 % of full scale range should be used. Feed the analyser with the gas, with the same flow rate and pressure as for sample gases. When the analyser reaches equilibrium, adjust the analyser output to the carbon dioxide content of the specified gas ± 0,01 %.

F.3 Check of propane mass flow controller or rotameter

F.3.1 General

The accuracy of the mass flow controller or rotameter may be checked by using a single cylinder of propane and the gas burner set at the propane mass flow rate as used for either the 20,5 kW or 30,0 kW nominal HRR. The gas usage rate is determined from the initial and final weight of the gas cylinder. Use a balance or weighing platform with an accuracy of 5 g or better.

F.3.2 Actions

1. Place the cylinder on the weighing platform and connect it to the supply system.

2. Set up the test facility as in a normal calibration test with backing boards, if any, fitted. Ignite the main burner and adjust the gas supply to 20,5 kW or 30,0 kW, to have the burner running at the rate as used during normal tests.

3. Record the weight of the cylinder and simultaneously start a timing device.

4. After (1 800 ± 30) s, again record the weight of the cylinder and simultaneously stop the timing device.

5. Determine the average rate of usage of gas in mg/s.

F.3.3 Criterion

The average rate of usage of gas set in b) and determined in e) should be equal within 5 %.

F.4 Optical filter check for white light systems

F.4.1 General

The smoke measurement system may be calibrated using the following procedure. A light system calibrated according to this procedure is expected to meet the requirements described in Annex E. The filters used for this check should be of the absorption type and calibrated for the correct wave length(s) of the optical system.

F.4.2 Actions

Perform the following steps with the measuring equipment operating and with an empty ladder in position in the chamber.

1. Place a light blocking insert into the filter holder and adjust to zero. ,

2. Remove the light blocking insert and adjust the signal from the light receiver to 100 %.

3. Start the time measurement and record the signal from the light receiver for a period of two minutes.

4. Introduce one of the following filters and record the corresponding signal for at least one minute

where the filters to be used are with optical density (d) 0,1 - 0,3 - 0,5 - 0,8 -1,0 and 2,0.

5. Repeat step d) for the other filters.

6. Stop the data acquisition and calculate the mean transmission values for all filters.

F.4.3 Criterion

Each <Avalue calculated from the mean transmission value (d = - lg(/)) should be within ± 5 % or ± 0,01 of the theoretical d-value of the filter, whichever is the greater.

NOTE Theoretical transmission values for the given rf-values 0,1 - 0,3 - 0,5 - 0,8 -1,0 - 2,0 using the given formula, are 79,43 % - 50,12 % - 31,62 % -15,85 % -10 % and 1 %.Annex G
(normative)

Calculation of HRR_av, SPR_av and FIGRA

G.1 Calculation of HRR_av

The average I [RR, HRR_av, is equal to HRR30s. Exceptions include the first 12 s following the ignition of the burner, and the 12 s period prior to 1 200 s, the completion of the burner on phase of the test.

G.1.1 For/* + 15 s < t < t„ + 1 185 s: HRR_m(t) = HRR30s (t)

, _x [((0.5 * HRR(t -15^)) + HRR(t -12s) +... + HRR(t + 12s) + (0.5 * HRR(t +15s))l

HRR30s (t) = ^л1

10

G.1.2 For data points collected over the first 12 s after burner ignition time, t_b, the average is taken only over the widest possible symmetrical range of data points within the exposure period:

G.1.3 For data points collected over the final 12 s prior to extinguishing the burner, the average is taken only over the widest possible symmetrical range of data points within the exposure period:

G.2 Calculation of SPR_av

The average SPR, SPR_av, is equal to SPR60s. Exceptions include the first 27 s following the ignition of the burner, and the 27 s period prior to 1 200 s, the completion of the burner on phase of the test.

G.2.1 For t_b + 30 s < t < t_b + 1 170 s: SPR_av(t) = SPR60s (/)

_cnD<n / ч [((°>⁵* SPR(J - 30 s)) + SPR(t - 27 5) + ... + SPR(t + 27 5) + (0,5 * SPR(t + 30 5))] SPRoOs (t) = ■—' ²

G.2.2 For data points collected over the first 27 s after burner ignition time, t_b, the average is taken only over the widest possible symmetrical range of data points within the exposure period:

For t = t_bs:

SPR_ar(t_bs) = 0

For t = t_b+ 3 s

SPR_ar(t_b+ 3 s) = SPR(t_b...t_b +65)

For t = t_b+ 6 s

SPR_m(t_b+ 6 s) = SPR(t_b...t_b +12 s) _et cetera, until

For t = t_b+ 27 s

SPR_m, (t„ + 27 s) = SPR(t_b...t_b + 54 5)

G.2.3 For data points collected over the final 27 s prior to extinguishing the burner, the average is taken only over the widest possible symmetrical range of data points within the exposure period:

For t = t_b+ 1 173 s

SPR,,,. (t_b+ 1 173 s) = SPR(} 146 t_b...t_b + 1 200 5)

For t = t_b+ 1176 s

SPR_av(t_b+ 1 176 s) = SPR( 152 t_b--t_b +1 200 s) et cetera, until

For t = t_b+ 1 197 s

SPR_av(t_b+ 1 197s) = SPR(i 194 + 1 200 5)

For t = t_b+ 1 200 s

SPR_ar(t_b+ 1 200 s) = SPR (t_b+ 1 200 s)

G.3 Calculation of the Fire Growth Rate Index (FIGRA)

The FIGRA is defined as the maximum of the quotient HRR_av(t) / (r - t_b). The quotient is calculated only for that part of the exposure period in which the threshold levels for HRR_ar and THR have been exceeded. If one or both threshold values are not exceeded during the exposure period, FIGRA is equal to zero.

FIGRA = 1 000 * max

,for . (/ > (1 — +тия)^Л 0 — "*■ 1 200 5)

where

FIGRA is the fire growth rate index [W/s];

HRR_av(t) is the average of HRR(t) as specified in G.1) [kW];

max[a(t),b,] is the maximum of the function aft) for the given t values />,.

The moments in time the threshold values are exceeded are defined as:

t, _ш is the first moment after t = t_b at which HRR_av(t) > 3 kW;

/, thr is the first moment after t = t_b at which THR(t) > 0,4 MJ.

Annex H

(informative)

Guidance on the choice of test equipment

NOTE The information given in this annex, covering named products and their suppliers, is given for the convenience of users of this standard and does not constitute an endorsement by CLC/TC 20 of the product named. Other products meeting the requirements of 6.5.2 may be used.

Examples of materials which have been found to be suitable for the backing board are

1. MonoliteMI;

2. Supalux;

Promatect H.AnnexI
(informative)

Guidance on the file format for data from the test

For easy exchange of test results, test data should be stored in a standard format. The principle objective is that the file should contain all the required information including both visually observed/recorded and automatically recorded data. It should be possible to perform all requested calculations.

The data of a test should be stored in an ASCII-file with 17 tab-separated columns of data. More columns (with non-compulsory data) are allowed when they are placed after the compulsory columns, not in between.

The file should contain a two-line header and additional lines with general information and automatically recorded (raw) data per time step.

The first header line contains the column header texts:

1. General information;

2. [empty];

3. time (s);

4. Gas mass flow meter (mg/s);

5. DPT (Pa);

6. Transmission (%);

7. mole percentage of oxygen (%);

8. mole percentage of CO₂ (%);

9. T_o (K) [Ambient temperature];

10. L (K) [Duct thermocouple 1];

11. T₂ (K) [Duct thermocouple 2];

12. T₃ (K) [Duct thermocouple 3];

13. mole percentage of CO (%);

n) Ambient pressure (kPa);

15. Air mass flow meter (mg/s);

16. Main photodiode output (-) [if using laser smoke system];

17. Compensating photodiode output (-) [if using laser smoke system].

The second line is not specified (empty by default).

Subsequent lines contain general information in the first two columns and automatically recorded (raw) data in the next 15 columns. Only the first 76 lines in columns one and two are used. In columns 3 to 17 the vector data from each transducer is given at a time interval of 3 s.

The general information (regarding the test, product, laboratory, apparatus, pre-test and end of test conditions, and visual observations) is given in column two, with a description of what is presented in column one. The row order of the different items is given in the example below.Table 1.1 - Example of the recommended raw data file format

C

Column 1

olumn 2