IEC 61034 1 Edition 3 1 2013 06 INTERNATIONAL STANDARD NORME INTERNATIONALE Measurement of smoke density of cables burning under defined conditions – Part 1 Test apparatus Mesure de la densité de fumé[.]
Purpose
The purpose of the blank test is to condition the interior of the cube to the specified temperature range, when necessary, prior to carrying out tests.
Procedure
8.2.1 Burn approximately 1 l of alcohol as detailed in Clause 6, in order to preheat the test enclosure
8.2.2 Purge the inside of the cube of all combustion products by operating the extraction system
To ensure consistent results from the test cube and optical system when identical cables are burned under the same conditions, the test apparatus must undergo qualification This qualification is achieved through the qualification burning test as outlined in Clause 10, ensuring that the test apparatus meets all specified requirements.
Purpose
The qualification burning test aims to confirm that the smoke generated in the cube produces A C values that fall within the specified limits outlined in section 10.6 for both alcohol and toluene fire sources mentioned in section 10.3.
Preparation of cube
Clean the windows of the photometric system to regain 100 % transmission after stabilization of the voltage
Before starting the test, ensure the cube's internal temperature is between 25 °C ± 5 °C, measured at the door surface 1.5 m to 2.0 m high and at least 0.2 m from the walls If needed, perform a blank test to acclimate the cube's interior to the required temperature range.
Qualification fire sources
Two mixtures of pro analysis (PA) toluene and alcohol will be prepared in specific volume ratios: mixture a) consists of 4 parts toluene to 96 parts alcohol, while mixture b) contains 10 parts toluene to 90 parts alcohol Accurate measurement will be ensured using a pipette and volumetric flask.
To prepare the two mixtures, measure 40 ml of toluene for mixture a) or 100 ml for mixture b) into a 1.0 l volumetric flask using a pipette, then add alcohol until reaching the 1.0 l calibration mark.
NOTE PA toluene has a purity greater than 99,5 %
The mixtures shall be contained in a tray as described in Clause 6.
Test procedure
Burn 1 l ± 0,01 l of the test solutions specified in 10.3 Record the minimum of the measured transmittance level I t during the test.
Calculation
Calculate the measured parameter (A m ) as follows: t
“where I 0 is the initial transmittance level of incident light and I t(min) is the minimum of the measured transmittance level during the qualification test.”
Requirements
The calculated values of A C shall fall between the following limits:
1 light source 6 optical path height 2 150 ± 100
2 draught screen (height 1 000 ± 50) 7 fan flow 7 m 3 /min to 15 m 3 /min
3 direction of air flow from fan 8 photocell
Figure 1 – Plan view of test chamber
2 voltage supply 12,0 V ± 0,1 V(stabilized range ± 0,01 V) 6 windows of the cube
3 quartz/halogen bulb 7 window for dust protection
4 lens system 8 tube, matt finished inside
9 photocell The light source and the photocell shall be physically isolated from the walls of the cube
The diameter of the cone of light on the opposite face from the source is approximately 1,5 m
Early test chamber requirements specified uniform heat loss through walls, akin to 2 mm of steel, but this is now less critical due to the introduction of the toluene verification procedure It is essential to ensure pressure equalization and to arrange suitable measures accordingly Condensation at lower operating temperatures can lead to inaccurate results, with 15 °C being unacceptable, 18 °C as the minimum, and 20 °C as the safe minimum The tray holding the toluene mixture should be elevated to allow for proper air circulation Additionally, the water content in alcohol significantly influences smoke production values; thus, it is crucial to monitor the ethanol's water content during calibration tests and conduct these tests within 2 hours of mixing Finally, fan throughput must be certified or verified using appropriate methods, such as an anemometer placed at the end of a tube with a diameter matching the blade sweep and a length of at least 1.0 m.
In the optical system, verifying the output of the light source is unnecessary, as the actual power does not affect test accuracy; bulbs can be operated until failure since all measurements are relative to the initial intensity Additionally, the impact of color temperature and bulb emissivity at different wavelengths is minimal, especially considering that the receptor is adjusted for human eye response, which accounts for any loss of intensity at the blue end or gain at other wavelengths.
The aging of bulbs results in a "red" end of the spectrum, but these wavelengths have minimal impact when weighted by the receptor Consequently, the precision of the initial d.c voltage applied to the bulb is of little significance; using 12.1 V or 11.9 V instead of 12.0 V only affects absolute intensity and color temperature, both of which have negligible effects on the results The key aspect is to maintain a stable voltage within ±0.01 V during testing, regardless of whether it is set at 11.9 V, 12.0 V, or 12.1 V The receptor cell, such as the selenium cell Megatron MF45 1, operates effectively within its linear range, becoming non-linear at 40 mV, while the actual output in the testing conditions is approximately 3.5 mV Additionally, standard neutral density filters are essential to ensure that the system's relative response remains consistent over time.
Before the calibration of the photometric system, it is desirable that the filters are calibrated to confirm the specified nominal values
The Megatron MF45 is a commercially available product that serves as a suitable example This information is provided for the convenience of users and does not imply any endorsement by the IEC.
After calibrating the light beam intensity, it is essential to confirm the linear response to the filters using an appropriate light meter Although the relative nature of the I₀/Iₜ measurement suggests that cleaning the optical system's windows may not be necessary, it is advisable to clean them after each test This is due to the significant variation in reflection from the detector window caused by small amounts of deposited smoke, which can lead to increased light transmission despite the presence of smoke Regular cleaning ensures greater consistency in measurements.
A continuous air flow of up to 2 l/min may be allowed to sweep the window surfaces during testing The light source is configured to create a diffuse and defocused illumination to ensure that the photocell samples a small section of a large, uniformly lit area This setup helps avoid inaccuracies caused by bright patches outside the monitored area, which could scatter light into the cell and lead to false readings when smoke is present.
For this reason, the diameter of the light area should not be too small and should conform to the specified limits
IEC 60879:1986, Performance and construction of electric circulating fans and regulators
10 Essai de combustion de qualification 23
10.3 Sources de combustion de qualification 23
Annexe A (informative) Guide pour la procédure d'essai 26
Figure 1 – Vue en plan de l'enceinte d'essai 24
MESURE DE LA DENSITÉ DE FUMÉES DEGAGÉES PAR DES CÂBLES
BRÛLANT DANS DES CONDITIONS DÉFINIES –
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Cette version consolidée de la CEI 61034-1 comprend la troisième édition (2005)
[documents 20/754/FDIS et 20/766/RVD] et son amendement 1 (2013) [documents
20/1428/FDIS et 20/1443/RVD] Elle porte le numéro d'édition 3.1
The technical content of this consolidated version is identical to that of the base edition and its amendment; it has been prepared for user convenience A vertical line in the margin indicates where the base publication has been modified by Amendment 1 Additions and deletions are highlighted in red, with deletions struck through.
La Norme internationale CEI 61034-1 a été établie par le comité d’études 20 de la CEI:
The key changes from the previous edition include: a) a more precise definition of the screen and openings; b) a clearer definition of the support for the tested cables; and c) the removal of minor differences compared to CENELEC's work to achieve a parallel vote on the text's content.
Elle a le statut de publication groupée de sécurité, conformément au Guide 104 de la CEI
Cette publication a été rédigée selon les Directives ISO/CEI, Partie 2
La CEI 61034 comprend les parties suivantes, présentées sous le titre général Mesure de la densité de fumées dégagées par des câbles brûlant dans des conditions définies,
Partie 2: Procédure d’essai et exigences
The committee has determined that the content of the original publication and its amendment will not be altered before the stability date specified on the CEI website.
"http://webstore.iec.ch" dans les données relatives à la publication recherchée A cette date, la publication sera
• remplacée par une édition révisée, ou
Objet
L'objet de l'essai à blanc est de conditionner l'intérieur de l'enceinte d'essai dans la gamme de températures spécifiée, lorsque cela est nécessaire, avant d'entreprendre les essais.
Procédure
8.2.1 Brûler approximativement 1 l d'alcool tel que défini à l’Article 6, en vue de préchauffer l'enceinte d'essai
8.2.2 Purger l'intérieur du cube de tous les produits de combustion, en utilisant le système d'extraction
To ensure that the combination of the test chamber and optical system yields results consistent with those obtained in other chambers when identical cables are burned under the same conditions, the testing apparatus must undergo qualification This qualification is achieved by conducting a qualification combustion test (see Article 10) The testing apparatus must meet the required standards.
10 Essai de combustion de qualification
Objet
The purpose of the qualification combustion test is to ensure that the smoke produced in the test chamber yields A c values within the limits specified in section 10.6 for both alcohol-toluene sources described in section 10.3.
Préparation du caisson
Nettoyer les vitres du système photométrique pour retrouver une transmission de 100 % après stabilisation de la tension
Before starting the test, the internal temperature of the chamber must be within the range of 25 °C ± 5 °C This temperature should be measured on the inner surface of the chamber door, at a height of 1.5 m to 2.0 m, and at least 0.2 m away from the walls If necessary, conduct a blank test to condition the interior of the chamber to the specified temperature range.
Sources de combustion de qualification
Deux mélanges, a) et b), de toluène (qualité pour analyse) et d'alcool (tel que défini à l'Article
The mixtures should be prepared using the following volume proportions: a) 4 parts toluene to 96 parts alcohol, and b) 10 parts toluene to 90 parts alcohol It is essential to use a pipette and a graduated flask to ensure accurate measurements.
The two mixtures should be prepared by measuring the required amount of toluene, 40 ml for mixture a) or 100 ml for mixture b), in a 1.0 l volumetric flask using a pipette, and then adding alcohol up to the 1.0 l calibration mark.
NOTE Le toluène de qualité pour analyse a une pureté supérieure à 99,5 %
Les mélanges doivent être contenus dans un bac tel que celui décrit à l'Article 6.
Procédure d'essai
Brûler 1 l ± 0,01 l des solutions d'essais spécifiées en 10.3 Enregistrer les minimums mesurés du niveau de transmittance I t mesuré pendant l'essai.
Calcul
Calculer le paramètre mesuré (A m ) comme suit: t
"ó I 0 est le niveau initial de transmittance initiale de lumière incidente et I t(min) est le niveau minimum de transmittance mesuré pendant l'essai de qualification."
Exigences
Les valeurs calculées de A c doivent être comprises dans les limites suivantes:
1 source lumineuse 6 hauteur du trajet optique 2 150 ± 100
2 paravent (hauteur 1 000 ± 50) 7 débit du ventilateur 7 m 3 /min à 15 m 3 /min
3 direction du débit d’air du ventilateur 8 cellule photoélectrique
4 support pour les câbles 9 porte
Figure 1 – Vue en plan de l'enceinte d'essai
(stabilisée avec une tension de ± 0,01 V)
7 fenêtre de protection contre les poussières
3 lampe à quartz/à halogène 8 tube, surface interne mate
La source lumineuse et la cellule photoélectrique ne doivent pas être solidaires des parois du cube
Le diamètre du cône lumineux sur la surface opposée à la source est de 1,5 m environ
Guide pour la procédure d'essai
The initial requirements for the test chamber included specifications for the walls to ensure uniform heat loss, similar to
The significance of 2 mm steel has diminished with the introduction of the toluene verification procedure It is crucial to implement necessary arrangements for pressure equalization At the lower limit of the operating temperature range, condensation can lead to abnormal results; for instance, 15 °C is unacceptable, 18 °C is the minimum, and 20 °C is the specified safe minimum It is advisable to elevate the container holding the toluene mixture above the floor to facilitate air circulation Additionally, the water present in alcohol can significantly impact smoke production.
For calibration testing, it is crucial to consider the water content in ethanol to ensure the percentage remains within defined limits, and the test should be conducted within 2 hours of mixing Additionally, it is recommended that the fan flow rate be either certified or verified using an appropriate method, such as employing an anemometer positioned at the end of a tube with a diameter equal to that of the blades and a sufficient length, for instance, 1.0 m.
The optical system does not require verification of the light source's efficiency, as the actual power does not affect the accuracy of the test; all measurements of intensity are relative to the initial value Additionally, the impact of color temperature and lamp emissivity at various wavelengths is minimal, especially since the receiver is calibrated to human eye sensitivity Changes in intensity at the extreme blue or red ends of the spectrum due to normal lamp aging are insignificant, as these wavelengths have little effect on measurements by the receiver Consequently, the precise value of the initial direct current voltage applied to the lamps is of little importance.
When using a voltage of 12.1 V or 11.9 V instead of the standard 12.0 V in direct current, the primary effects are a change in absolute intensity and a modification of color temperature However, as previously established, these effects have minimal impact on the results The key characteristic of the voltage applied to the lamp is the necessity for it to remain stable within a very narrow tolerance Ideally, the voltage should be maintained at ±0.01 V throughout the testing period, although it is not critical for the voltage to be perfectly stabilized.
The receiver cell is designed to operate effectively within the linear range of its specifications, typically around 11.9 V, 12.0 V, or 12.1 V For instance, the Mégatron MF 45 1 selenium cell becomes nonlinear at an output voltage of 40 mV, while the actual output voltage under cabin lighting conditions is approximately 3.5 mV.
The Mégatron MF 45 is a suitable product available on the market This information is intended for users of the current standard and does not imply that the IEC endorses or recommends the exclusive use of this designated product Additionally, the use of neutral density filters is essential to ensure that the system's relative response remains consistent from month to month.
Avant la calibration du système photométrique, il est souhaitable que les filtres soient calibrés afin de confirmer les valeurs nominales spécifiées
When a change occurs in the intensity of light after calibration, it is essential to verify the linear response of the filters using an appropriate lumen meter The fundamental concept of measuring the ratio \( I_0/I_t \) suggests that, theoretically, it may not be necessary to clean the optical system's windows before use However, in practice, cleaning is advisable after each test due to the significant variation in reflection on the detector window caused by even small amounts of deposited smoke Interestingly, a slight deposit of smoke can enhance light transmission by reducing the reflective qualities of the surface Therefore, cleaning the windows after each test or series of tests ensures consistency in results.
In an alternative approach, a continuous air flow with a maximum rate of 2 l/min can be used to sweep the window surfaces during the test The light source is positioned to provide a diffuse and defocused surface for two main reasons: one has already been mentioned, while the primary reason is to enable the cell to capture a small portion of a larger, uniformly illuminated area.
This prevents situations where, for instance, a bright spot exists just outside the area controlled by the cell If smoke is emitted, it could cause light to scatter within the cell, resulting in an inaccurate reading.
Pour cette raison, il convient que le diamètre de la surface éclairée ne soit pas trop petit et soit conforme aux limites spécifiées
CEI 60879:1986, Aptitude à la fonction et construction des ventilateurs électriques de circulation et leurs régulateurs de vitesse