Unlike different cables, fire resistant cables need to work even when immediately exposed to the fire to maintain essential Life Safety and Fire Fighting tools working: Fire alarms, Emergency Lighting, Emergency Communication, Fire Sprinkler pumps, Fireman’s Lift sub-main, Smoke extraction followers, Smoke dampers, Stair pressurization followers, Emergency Generator circuits and so on.
In order to classify electric cables as fire resistant they are required to undergo testing and certification. Perhaps the primary frequent fireplace exams on cables had been IEC 331: 1970 and later BS6387:1983 which adopted a gas ribbon burner test to provide a flame during which cables were placed.
Since the revision of BS6387 in 1994 there have been 11 enhancements, revisions or new test requirements introduced by British Standards to be used and utility of Fire Resistant cables however none of those appear to handle the core concern that fire resistant cables where tested to widespread British and IEC flame take a look at requirements usually are not required to carry out to the identical fireplace performance time-temperature profiles as every different structure, system or part in a building. Specifically, where fireplace resistant buildings, techniques, partitions, hearth doors, fire penetrations fireplace obstacles, flooring, walls and so forth. are required to be fireplace rated by building rules, they are tested to the Standard Time Temperature protocol of BS476 parts 20 to 23 (also generally identified as ISO834-1, ASNZS1530pt4, EN1363-1 and in America and Canada ASTM E119-75).
These checks are performed in massive furnaces to replicate real publish flashover fire environments. Interestingly, Fire Resistant cable take a look at standards like BS 6387CWZ, SS299, IEC 60331 BS8343-1 and a pair of, BS8491 solely require cables to be uncovered to a flame in air and to decrease final take a look at temperatures (than required by BS476 pts 20 to 23). Given Fire Resistant cables are likely to be uncovered in the identical fire, and are needed to make sure all Life Safety and Fire Fighting systems remain operational, this fact is maybe stunning.
Contrastingly in Germany, Belgium, Australia, New Zealand, USA and Canada Fire Resistant cable systems are required to be tested to the same fireplace Time Temperature protocol as all different constructing elements and that is the Standard Time Temperature protocol to BS476pts 20-23, IS0 834-1, EN1363-1 or ASTM E119-75 in USA.
The committees growing the usual drew on the steering given from the International Fire Prevention Congress held in London in July 1903 and the measurements of furnace temperatures made in many fireplace checks carried out in the UK, Germany and the United States. The checks have been described in a collection of “Red Books” issued by the British Fire Prevention Committee after 1903 as nicely as these from the German Royal Technical Research Laboratory. The finalization of the ASTM commonplace was heavily influenced by Professor I.H. Woolson, a Consulting Engineer of the USA National Board of Fire Underwriters and Chairman of the NFPA committee in Fire Resistive Construction who had carried out many checks at Columbia University and Underwriters Laboratories in Chicago. The small time temperature differences between the International ISO 834-1 test as we know it at present and the America ASTM E119 / NFPA 251 exams doubtless stemmed from this time.
Image courtesy of MICC Ltd.
The curve as we see it today (see graph above) has turn into the standard scale for measurement of fireplace test severity and has proved related for most above ground cellulosic buildings. When parts, buildings, components or methods are tested, the furnace temperatures are managed to conform to the curve with a set allowable variance and consideration for initial ambient temperatures. The standards require components to be tested in full scale and under conditions of support and loading as outlined in order to represent as accurately as potential its functions in service.
This Standard Time Temperature testing protocol (see graph right) is adopted by nearly all international locations around the globe for fireplace testing and certification of just about all building buildings, parts, systems and components with the interesting exception of fireside resistant cables (exception in USA, Canada, Australia, Germany, Belgium and New Zealand where fireplace resistant cable techniques are required to be tested and accredited to the Standard Time Temperature protocol, just like all other building constructions, elements and components).
It is necessary to grasp that application requirements from BS, IEC, ASNZS, DIN, UL and so forth. the place hearth resistive cables are specified for use, are only ‘minimum’ necessities. We know today that fires are not all the same and analysis by Universities, Institutions and Authorities all over the world have identified that Underground and some Industrial environments can exhibit very completely different fireplace profiles to those in above ground cellulosic buildings. Specifically in confined underground public areas like Road and Rail Tunnels, Underground Shopping centers, Car Parks hearth temperatures can exhibit a really fast rise time and can reach temperatures nicely above those in above floor buildings and in far less time. In USA today electrical wiring systems are required by NFPA 502 (Road Tunnels, Bridges and different Limited Access Highways) to face up to fireplace temperatures as a lot as 1,350 Degrees C for 60 minutes and UK British Standard BS8519:2010 clearly identifies underground public areas corresponding to automotive parks as “Areas of Special Risk” the place extra stringent take a look at protocols for important electric cable circuits might must be thought of by designers.
Standard Time Temperature curves (Europe and America) plotted towards common BS and IEC cable tests.
Of course all underground environments whether highway, rail and pedestrian tunnels, or underground public environments like shopping precincts, automobile parks etc. could exhibit different hearth profiles to these in above ground buildings as a end result of In these environments the warmth generated by any fireplace can not escape as easily as it might in above floor buildings thus relying more on heat and smoke extraction equipment.
For Metros Road and Rail Tunnels, Hospitals, Health care services, Underground public environments like purchasing precincts, Very High Rise, Theaters, Public Halls, Government buildings, Airports and so forth. this is significantly important. Evacuation of those public environments is commonly gradual even during emergencies, and it is our duty to make sure everyone is given the very best probability of secure egress throughout hearth emergencies.
It is also understood today that copper Fire Resistant cables the place installed in galvanized steel conduit can fail prematurely throughout hearth emergency due to a reaction between the copper conductors and zinc galvanizing contained in the metal conduit. In 2012 United Laboratories (UL®) in America eliminated all certification for Fire Resistive cables the place installed in galvanized metal conduit for that reason:
UL® Quote: “A concern was brought to our attention related to the performance of those products within the presence of zinc. We validated this finding. As a results of this, we modified our Guide Information to point that every one conduit and conduit fittings that are available in contact with hearth resistive cables ought to have an interior coating free of zinc”.
Time temperature profile of tunnel fires utilizing automobiles, HGV trailers with totally different cargo and rail carriages. Graph extract: Haukur Ingason and Anders Lonnermark of the Swedish National Testing and Research Institute who offered the paper on the First International Symposium in Prague 2004: Safe and Reliable Tunnels.
It would appear that some Standards authorities around the world might must review the current check methodology at present adopted for fireplace resistive cable testing and perhaps align the efficiency of Life Safety and Fire Fighting wiring techniques with that of all the other fireplace resistant constructions, elements and techniques so that Architects, building designers and engineers know that after they need a hearth score that the essential wiring system might be equally rated.
For many energy, control, communication and knowledge circuits there’s one technology out there which can meet and surpass all present fireplace tests and functions. It is a solution which is incessantly utilized in demanding public buildings and has been employed reliably for over 80 years. MICC cable expertise can present a complete and complete answer to all the problems related to the fireplace safety risks of recent flexible organic polymer cables.
The metal jacket, magnesium oxide insulation and conductors of MICC cables ensure the cable is successfully hearth proof. Bare MICC cables haven’t any natural content so merely cannot propagate flame or generate any smoke. The zero fuel-load of those MICC cables ensures no warmth is added to the fireplace and no oxygen is consumed. Being inorganic these MICC cables cannot generate any halogen or poisonous gasses at all including Carbon Monoxide. เพรสเชอร์เกจคือ can meet all the present and constructing hearth resistance performance standards in all international locations and are seeing a significant enhance in use globally.
Many engineers have previously considered MICC cable technology to be “old school’ however with the brand new research in fire performance MICC cable system are actually confirmed to have far superior fireplace performances than any of the newer more fashionable flexible fireplace resistant cables.
For further info, go to www.temperature-house.com
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