flixborough(nyprouk)* - fire consultancy

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46 Nypro (UK) site at Flixborough was severely damaged by a large explosion. The factory produced nylon, the time of the explosion is well documented, the village post office clock stopped as a result of the explosion blast pressure wave, the village located 2 miles from the blast site & around 1800 homes damaged within a mile radius of the site. 28 workers were killed with a further more 36 suffering injuries. Had the accident happened during a weekday then it is likely the accident would have claimed more casualties; the flame jet hit the office block, which would have had over 50 people at work and with 200 people at the factory. Local witnesses reported feeling the blast pressure as window blew out but didn’t hear a blast noise. Prior to the accident it was discovered that reactor 5 was leaking and as a precaution the plant was shut down and by passing the process to reactors 4 and 6 the installation of the bypass failed and caused a fire and ruptured some other process pipes allowing product to escape forming a large flammable cloud and at around 5pm found its way to an ignition source causing an explosion and extensive damage which burned for a during for 10 days A plant modification occurred without a full assessment of the potential consequences and only limited calculations were undertaken to assess the integrity of the bypass line. Therefore. poor management control and poor assessment for the risks. Study of the remaining vessels and items on site suggest the kind of overpressures experienced during the blast, in addition calculation for the vapour cloud and its air fuel mass helped predict the size equivalent to an explosive measure in this case, various reports conclude that the net crushing pressure on the skirts of these vessels must have been in excess of 760 kPa (7.6 bar) and that the explosion its self is as much as 15 bar. Flixborough (Nypro UK) June 1, 1974 Event Statistics 10 Days Lesions Learned Duration of fire Number of casualties Cost to industry References 28 Staff, 38 others suffered injuries £100 million Flixborough. 1974.[Online]. [Accessed 31 October 2014]. http://www.hse.gov.uk/comah/sragtech/caseflixboroug74 Prof. Andrews. 2014. Flixborough incident. Fire Explosion Prediction & Mitigation, October, 2014, Weetwood Hall Leeds. Type of fire Vapour Cloud Unknown Ignition Source

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Page 1: Flixborough(NyproUK)* - Fire Consultancy

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 Nypro  (UK)  site  at  Flixborough  was  severely  damaged  by  a  large  explosion.  The  factory  produced  nylon,  the  time  of  the  explosion  is  well  documented,  the  village  post  office  clock  stopped  as  a  result  of  the  explosion  blast  pressure  wave,  the  village  located  2  miles  from  the  blast  site  &  around  1800  homes  damaged  within  a  mile  radius  of  the  site.  28  workers  were  killed  with  a  further  more  36  suffering  injuries.  Had  the  accident  happened  during  a  weekday  then  it  is  likely  the  accident  would  have  claimed  more  casualties;  the  flame  jet  hit  the  office  block,  which  would  have  had  over  50  people  at  work  and  with  200  people  at  the  factory.  Local  witnesses  reported  feeling  the  blast  pressure  as  window  blew  out  but  didn’t  hear  a  blast  noise.  Prior  to  the  accident  it  was  discovered  that  reactor  5  was  leaking  and  as  a  precaution  the  plant  was  shut  down  and  by  passing  the  process  to  reactors  4  and  6  the  installation  of  the  bypass  failed  and  caused  a  fire  and  ruptured  some  other  process  pipes  allowing  product  to  escape  forming  a  large  flammable  cloud  and  at  around  5pm  found  its  way  to  an  ignition  source  causing  an  explosion  and  extensive  damage  which  burned  for  a  during  for  10  days  

A  plant  modification  occurred  without  a  full  assessment  of  the  potential  consequences  and  only  limited  calculations  were  undertaken  to  assess  the  integrity  of  the  bypass  line.  Therefore.  poor  management  control  and  poor  assessment  for  the  risks.    Study  of  the  remaining  vessels  and  items  on  site  suggest  the  kind  of  overpressures  experienced  during  the  blast,  in  addition  calculation  for  the  vapour  cloud  and  its  air  fuel  mass  helped  predict  the  size  equivalent  to  an  explosive  measure  in  this  case,  various  reports  conclude  that  the  net  crushing  pressure  on  the  skirts  of  these  vessels  must  have  been  in  excess  of  760  kPa  (7.6  bar)  and  that  the  explosion  its  self  is  as  much  as  15  bar.        

Flixborough  (Nypro  UK)  June  1,  1974  

Event    Statistics  

10  Days  

Lesions  Learned  

Duration  of  fire  

Number  of  casualties  

Cost  to  industry  

References    

28  Staff,  38  others  suffered  injuries  

£100  million  

Flixborough.  1974.[Online].  [Accessed  31  October  2014].  http://www.hse.gov.uk/comah/sragtech/caseflixboroug74  Prof.  Andrews.  2014.  Flixborough  incident.  Fire  Explosion  Prediction  &  Mitigation,  October,  2014,  Weetwood  Hall  Leeds.    

Type  of  fire  Vapour  Cloud    

Unknown  Ignition  Source