Unlike เกจวัดแรงดันไฮดรอลิค , fire resistant cables have to work even when directly uncovered to the fire to maintain essential Life Safety and Fire Fighting equipment working: Fire alarms, Emergency Lighting, Emergency Communication, Fire Sprinkler pumps, Fireman’s Lift sub-main, Smoke extraction followers, Smoke dampers, Stair pressurization fans, Emergency Generator circuits etc.
In order to classify electric cables as fire resistant they’re required to endure testing and certification. Perhaps the primary common hearth tests on cables were IEC 331: 1970 and later BS6387:1983 which adopted a fuel ribbon burner test to produce a flame in which cables had been positioned.
Since the revision of BS6387 in 1994 there have been eleven enhancements, revisions or new take a look at requirements introduced by British Standards for use and utility of Fire Resistant cables however none of these appear to address the core problem that fireplace resistant cables the place tested to widespread British and IEC flame check standards usually are not required to perform to the identical hearth efficiency time-temperature profiles as each different structure, system or component in a constructing. Specifically, the place fireplace resistant constructions, methods, partitions, fire doors, fire penetrations fire obstacles, floors, walls and so on. are required to be hearth rated by building laws, they are examined to the Standard Time Temperature protocol of BS476 components 20 to 23 (also often known as ISO834-1, ASNZS1530pt4, EN1363-1 and in America and Canada ASTM E119-75).
These checks are conducted in large furnaces to duplicate real post flashover fire environments. Interestingly, Fire Resistant cable check requirements like BS 6387CWZ, SS299, IEC 60331 BS8343-1 and 2, BS8491 solely require cables to be uncovered to a flame in air and to lower final check temperatures (than required by BS476 pts 20 to 23). Given Fire Resistant cables are prone to be uncovered in the identical hearth, and are wanted to ensure all Life Safety and Fire Fighting techniques stay operational, this truth is probably shocking.
Contrastingly in Germany, Belgium, Australia, New Zealand, USA and Canada Fire Resistant cable systems are required to be examined to the same fire Time Temperature protocol as all different building components and this 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 lots of hearth checks carried out in the UK, Germany and the United States. The exams were described in a sequence of “Red Books” issued by the British Fire Prevention Committee after 1903 in addition to those from the German Royal Technical Research Laboratory. The finalization of the ASTM normal was closely 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 exams at Columbia University and Underwriters Laboratories in Chicago. The small time temperature differences between the International ISO 834-1 test as we know it right now and the America ASTM E119 / NFPA 251 tests doubtless stemmed from this time.
Image courtesy of MICC Ltd.
The curve as we see it right now (see graph above) has become the usual scale for measurement of fireplace test severity and has proved relevant for many above floor cellulosic buildings. When components, structures, parts or systems are tested, the furnace temperatures are managed to conform to the curve with a set allowable variance and consideration for preliminary ambient temperatures. ที่วัดแรงดัน require parts to be tested in full scale and under conditions of help and loading as defined to have the ability to characterize as precisely as attainable its capabilities in service.
This Standard Time Temperature testing protocol (see graph right) is adopted by nearly all countries all over the world for fire testing and certification of virtually all constructing constructions, elements, methods and parts with the attention-grabbing exception of fireplace resistant cables (exception in USA, Canada, Australia, Germany, Belgium and New Zealand where hearth resistant cable techniques are required to be examined and approved to the Standard Time Temperature protocol, identical to all other building structures, components and components).
It is essential to understand that application requirements from BS, IEC, ASNZS, DIN, UL etc. the place hearth resistive cables are specified for use, are solely ‘minimum’ necessities. We know at present that fires usually 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 totally different hearth 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 very quick rise time and may reach temperatures nicely above these in above ground 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 resist fire temperatures up to 1,350 Degrees C for 60 minutes and UK British Standard BS8519:2010 clearly identifies underground public areas similar to automotive parks as “Areas of Special Risk” where more stringent check protocols for essential electric cable circuits could need to be thought of by designers.
Standard Time Temperature curves (Europe and America) plotted towards widespread BS and IEC cable exams.
Of course all underground environments whether or not street, rail and pedestrian tunnels, or underground public environments like purchasing precincts, car parks and so forth. may exhibit totally different hearth profiles to those in above floor buildings as a outcome of In these environments the warmth generated by any hearth cannot escape as easily as it’d in above ground buildings thus relying more on heat and smoke extraction equipment.
For Metros Road and Rail Tunnels, Hospitals, Health care facilities, Underground public environments like shopping precincts, Very High Rise, Theaters, Public Halls, Government buildings, Airports and so on. that is particularly important. Evacuation of those public environments is usually slow even throughout emergencies, and it is our duty to make sure everyone is given the very best likelihood of safe egress throughout fireplace emergencies.
It is also understood at present that copper Fire Resistant cables the place installed in galvanized metal conduit can fail prematurely throughout hearth emergency because of a response between the copper conductors and zinc galvanizing contained in the metallic 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 delivered to our consideration associated to the efficiency of those products within the presence of zinc. We validated this finding. As a results of this, we modified our Guide Information to indicate that all conduit and conduit fittings that come in contact with fireplace resistive cables should have an inside coating freed from zinc”.
Time temperature profile of tunnel fires utilizing vehicles, HGV trailers with 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 seem that some Standards authorities all over the world may have to evaluation the present take a look at methodology presently adopted for hearth resistive cable testing and perhaps align the efficiency of Life Safety and Fire Fighting wiring methods with that of all the other fire resistant constructions, parts and methods so that Architects, building designers and engineers know that when they want a fire ranking that the important wiring system shall be equally rated.
For many energy, management, communication and data circuits there could be one expertise available which can meet and surpass all current fireplace tests and applications. It is a solution which is frequently used in demanding public buildings and has been employed reliably for over 80 years. MICC cable expertise can present a complete and full reply to all the issues associated with the fireplace safety dangers of modern flexible organic polymer cables.
The metal jacket, magnesium oxide insulation and conductors of MICC cables make sure the cable is successfully fire proof. Bare MICC cables don’t have any organic content so simply can’t propagate flame or generate any smoke. The zero fuel-load of these MICC cables ensures no warmth is added to the fire and no oxygen is consumed. Being inorganic these MICC cables cannot generate any halogen or toxic gasses in any respect together with Carbon Monoxide. MICC cable designs can meet all the present and constructing fire resistance performance requirements in all nations and are seeing a significant enhance in use globally.
Many engineers have previously thought of MICC cable expertise to be “old school’ however with the new analysis in hearth performance MICC cable system are now proven to have far superior fireplace performances than any of the newer extra fashionable versatile fire resistant cables.
For further info, go to www.temperature-house.com
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