BS EN 50399:2011 pdf download

BS EN 50399:2011 pdf download.Common test methods for cables under fire conditions—Heat release and smoke production measurement on cables during flame spread test- Test apparatus,procedures, results.
There shall be a chamber above the hood to allow a connection to the exhaust duct,
The system shall be designed to collect all the combustion products leaving the test chamber through the outlet during the test. There shall be no leakage of flames or smoke. The exhaust capacity shall be at least 1 m/s at normal pressure and a temperature of 25 C. The exhaust system design shall not be based on natural convection.
NOTE 3 bi cider to eu-act gaeee and vapoors. eeeeciy Si the ce ot heaSily bwnIng cable.. ci cable. eNcti iLii to be specially eminghed and produce hii vobjm.s of gases and vapotws. an esheist syslern witl a capacAy of 1.5 m’s is recommended.
4.4 Exhaust duct
An exhaust duct shall be connected to the hood as described in 4.3. The inner diameter, D, of the duct shall be in the range 250 mm to 400 mm. The straight section of the duct shall have a minimum length of 12 x D, such that a uniform flow profile is established at the point of measurement, NOTE A urilcim flow profile can be obtained by Introducing guide vane. (see Figure 31 below and alter the measunng eecbon
such es described In EN 14390 Thu is hi)liy recommended in cider to obtem es pree measurements as possible
4.5 Instrumentation in the exhaust duct
45.1 Volume flow
The flow shall b€ measured by a bidirectional probe located at the centre line of the duct and at a minimum distance from the beginning of the straight section of exhaust duct of 8 x 0. The length of the straight section of duct beyond the probe shall be at least 4 x U. The probe which is shown in Figure 4 consists of a stainless steel cylinder. 32 mm long and with an outer diameter of 16 mm. The cylinder is divided into two equal chambers. The pressure difference between the two chambers shall be measured by a pressure transducer. The plot of the probe response versus the Reynolds number is shown in Figure 5 (see also Annex C).
The pressure transducer shall have a measuring precision better than t 5 Pa. A suitable range of measurement is 0 Pa to 200 Pa (when using duct diameters between 250 mm and 400 mm).
The two connection pipes between the bidirectional probe and the pressure transducer shall be of the same length.
Gas temperature ii the immediate vicinity of the probe shall be measured by a sheathed K type thermocouple with a maximum diameter of 1,5 mm in accordance with EN 60584-1. The thermocouple shall be positioned so that it does not disturb the flow pattern around the bidirectional probe.
NOTE mote than cite thermnoooupie Is used then all thermocoi.elas shall be of the serne size and type
4.5.2 Sampling probe
The sampling probe shall be located where the exhaust duct flow Is well mixed. The probe shall have a cylindrical form so that disturbance of flow is minimised. The gas samples shall be taken along the whole diameter of the exhaust duct. Examples of suitable sampling probes are shown in Figure 6. The intake of the sampling probe shall be turned downstream in order to avoid soot clogging in the probe. The sampling probe shall be connected to the gas analysers for oxygen (0?) and carbon dioxide (C01) by a suitable sampling line,
4.5.3 Sampling line
The sampling line shall be manufactured from corrosion resistant material, e.g. PTFE. The combustion gases shall be filtered with inert fdters to the degree of particle concentration requwed by the gas analysis equipment. The filtering procedure shall be carried out In more than one step. The system shall be capable of removing water vapour.