STATE-OF-THE-ART SAFETY CIRCUITS LIKELY TO FAIL DURING A FIREProper methodology for cable selection and sizing providessol...
Background• The maintenance of safety services in a building during an emergency is  vital• During a fire, cables are expe...
BackgroundGraph from Dutch CopperInstitute (NederlandsKoperinstituut, Uitgave No 3,Koper en Koperlegeringen,1964, p 3-12):...
Case Study• This study was based on the design data of an actual large building, the  Galeria Tarnovia Shopping Centre in ...
Case Study ResultsUnder normal operating conditions (no fire): cable size selection is correctlymade according to state-of...
Case Study Results• Motor startup under fire conditions is often impossible as currents are  large due to a decrease in th...
Solution: Increasing the size of cable conductorsIn order to ensure the correct operation of fire safety equipment during ...
Conclusion and recommendations• It is essential to increase the cross-section of cable conductors to ensure  the correct o...
More information?• Read the full report and the application note at Leonardo Energy:  http://bit.ly/12mrSzW• Contact : Ste...
New Leonardo ENERGY website up and runningThanks to continuous effort from many people and organizations, the Leonardo Ene...
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News release - State-of-the-art safety circuits likely to stop functioning during a fire. Proper methodology for cable selection and sizing provides solution.

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Safety equipment and safety circuits in commercial buildings are likely to stop functioning in the event of a fire, even if they are designed and installed according to state-of-the-art methods and current regulations. This is due to the increased resistance at the temperature at which these circuits are required to function, according to the findings of a case study of a modern shopping mall in Tarnovia, Poland. This paper summarizes the case study results and provides a framework for the proper selection and sizing of conductors supplying electrical equipment that must remain functional during a fire.

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News release - State-of-the-art safety circuits likely to stop functioning during a fire. Proper methodology for cable selection and sizing provides solution.

  1. 1. STATE-OF-THE-ART SAFETY CIRCUITS LIKELY TO FAIL DURING A FIREProper methodology for cable selection and sizing providessolutionDr. Jacek Wasilewski and Dr. Wojciech WiechowskiWTW Power Solutions
  2. 2. Background• The maintenance of safety services in a building during an emergency is vital• During a fire, cables are expected to retain their functionality and provide power to essential equipment• The designer must take into account the increased electrical resistance at elevated temperature and thus the correct sizing of the conductor• Currently, cables are specified in terms that reflect their normal operational conditions, but design parameters under fire conditions are rarely specified State-of-the-art safety circuits likely to fail during a fire
  3. 3. BackgroundGraph from Dutch CopperInstitute (NederlandsKoperinstituut, Uitgave No 3,Koper en Koperlegeringen,1964, p 3-12):The conductivity of copperis a factor of 5 less duringfire. This is not taken intoaccount in current firesafety standards for cables. State-of-the-art safety circuits likely to fail during a fire
  4. 4. Case Study• This study was based on the design data of an actual large building, the Galeria Tarnovia Shopping Centre in Tarnow, Poland• First, conductor sizing for selected fire safety circuits based on selection criteria described in IEC 60364 was verified• In the second step, the steady-state and dynamic performance of selected fire safety equipment and the protective relays were verified through detailed dynamic simulations with a professional simulation tool | State-of-the-art safety circuits likely to fail during a fire
  5. 5. Case Study ResultsUnder normal operating conditions (no fire): cable size selection is correctlymade according to state-of-the-art methods and current regulations, e.g. theIEC standard 60364-4-41.For a maximum value of temperature for the standard fire temperature–timecurve:• The maximum allowable times of automatic disconnection of supply may often be exceeded• The maximum levels of voltage drop across circuits are often exceeded as well, which results in large currents that cause induction motor overload but not enough for the activation of thermal protection in the investigated scenarios State-of-the-art safety circuits likely to fail during a fire
  6. 6. Case Study Results• Motor startup under fire conditions is often impossible as currents are large due to a decrease in the supplying voltage, as well as motor stall• This implies that problems with operation of fire safety equipment, as well as with fast disconnection of fire safety circuits by protective relays, may occur when the temperature of wires of the supplying circuits is high due to a fire | State-of-the-art safety circuits likely to fail during a fire
  7. 7. Solution: Increasing the size of cable conductorsIn order to ensure the correct operation of fire safety equipment during afire, it is essential to:• Increase the cross-section of conductors of the supplying cables - to decrease voltage drop• Increase cable cross-section of the conductors of supplying cables and the protective conductor (or apply supplementary equipotential bonding) - to decrease phase-to-ground impedance and ensure sufficiently fast automatic disconnection of supply• Set thermal protection current settings to no less than 1.1 times the rated motor current in order to minimize the likelihood of circuit disconnection in cases of slight motor overloading. | State-of-the-art safety circuits likely to fail during a fire
  8. 8. Conclusion and recommendations• It is essential to increase the cross-section of cable conductors to ensure the correct operation of safety equipment during a fire• It is necessary to elaborate and evaluate standards and recommendations for fire safety circuits that include clear cable sizing criteria for the expected fire conditions• The longer the safety services remain operational, the better the chance of bringing a fire under control and reducing property damage. State-of-the-art safety circuits likely to fail during a fire
  9. 9. More information?• Read the full report and the application note at Leonardo Energy: http://bit.ly/12mrSzW• Contact : Stefan Fassbinder – stefan.fassbinder@copperalliance.de State-of-the-art safety circuits likely to fail during a fire
  10. 10. New Leonardo ENERGY website up and runningThanks to continuous effort from many people and organizations, the Leonardo Energy initiative hasbecome a reference for sustainable energy professionals. We are very proud of this and will continue ourefforts to remain one of the key players in this field.In line with this ambition, we have now entirely revamped our website, which is both our maincommunication platform and our main content management system.One of the primary reasons for this revamping was to give visitors easier access to relevant content.With the new search and filter functionality, you can select a technology, sector, purpose, channel , orcountry, or combine the different categories through a sequential filter to obtain more tailored results.Go to the tab “Find Resources” in the top menu. In addition, the Search field at the top of the websiteremains present for a more general way of searching content.Our new website also has a Community page where authors, speakers, experts, and members canregister on a peer-to-peer communication platform and then comment on various topics and learn fromeach other.We hope that the new website suits your needs, and we welcome your input and feedback. Pleasespread the word in your professional network.Best regards,The Leonardo Energy team | Presentation title and date

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