ISO Technical Committee 92 : Fire Safety

Fire-Induced Progressive ‘Damage’ or ‘Collapse’ ? More …

2012-05-02:  Last week, I attended joint meetings of CIB W14: ‘Fire Safety’ … and ISO Technical Committee 92: ‘Fire Safety’, Sub-Committee 3: ‘Fire Threat to People and the Environment’ & Sub-Committee 4: ‘Fire Safety Engineering’ … in Thessaloniki (Salonika), Greece.

The relationship between these two independent groups is symbiotic … ISO TC 92 develops International Fire Standards, while CIB W14 is the pre-normalization forum for discussion and action on a comprehensive approach to Fire Research and Innovation.

I should add, here, that CIB W14’s Aims & Objectives were substantially updated at our meeting in Thessaloniki … and I presented the CIB Research WG IV Reflection Document: ‘Structural Reliability & Fire-Induced Progressive Damage’ for discussion … which was lively, but far too short !

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While I was away, however, the following question was posed by Mr. Panagiotis Kotsovinos, on the Society of Fire Protection Engineers (SFPE-USA) Page of LinkedIn (http://www.linkedin.com/groups?gid=96627).

” I would like to please explain a bit more why the term ‘Fire-Induced Progressive Damage’ is preferred over ‘Fire-Induced Progressive Collapse’, and what is the confusion that exists widely as you say with the later definition ? “

Firstly, apologies for the late reply.  This was due to my absence from base … I am not continuously ‘plugged-in’ to the virtual environment while travelling.  But, I also wished to respond to this and other queries after some thought.  The issues raised are important.

Very briefly … it was NIST, in its 2005 Report, which introduced the term ‘Fire-Induced Progressive Collapse’ to a wide audience.  No definition, or elaboration, of this structural concept was provided in either the 2005 or 2008 Recommendations.  There is no confusion caused by ‘Fire-Induced’.

The reason I have been so quick to focus in on the distinction between ‘Damage’ and ‘Collapse’ is because we went through this whole debate, in Ireland … starting at the end of the 1980’s and continuing on through to the middle of 1990’s.  Because … in January 1987 … a Multi-Storey Apartment Block, called Raglan House, collapsed as a result of a gas explosion.  Two people were killed.  An examination of records at the time will reveal the same general confusion about technical terminology.  And … following the collapse, the Structural Engineering Profession was in disarray.

After a considerable amount of time witnessing, at close hand, these events … I formed the strong opinion that the proper connection of vertical and horizontal structural elements in a building was, and continues to be, a fundamental principle of all good structural engineering design … no matter what the height of the building.

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Colour photograph showing World Trade Center Building No. 7 in ruins, after 9-11 in New York City ... when Fire-Induced Progressive Damage led to Disproportionate Damage, and finally to total building failure ... a Collapse Level Event (CLE). Click to enlarge.

Colour photograph showing World Trade Center Building No. 7 in ruins, after 9-11 in New York City ... when Fire-Induced Progressive Damage led to Disproportionate Damage, and finally to total building failure ... a Collapse Level Event (CLE). Click to enlarge.

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Tackling the current confusion over technical terminology …

In 1987, Raglan House collapsed in Dublin.  In 2001, World Trade Center Building 7 collapsed in New York City.

In English … the word Collapse can have the following meanings, which are very broadly similar …

  • To fall down or cave in suddenly: the whole building collapsed ;
  • To fail completely ;
  • To break down or fall down from lack of strength ;
  • To fold (furniture, etc.) compactly or (of furniture, etc.) to be designed to fold compactly ;
  • The act or instance of suddenly falling down, caving in, or crumbling ;
  • A sudden failure or breakdown.

[from Latin, from collabi to fall in ruins, from labi to fall]

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Black and white image reproducing Figure 1-1 in NIST Report: 'Best Practices for Reducing the Potential for Progressive Collapse in Buildings' (NISTIR 7396, February 2007) ... showing a bird's eye view of the Disproportionate Damage at Ronan Point, in England, which was caused by a gas explosion in 1968. Click to enlarge.

Black and white image reproducing Figure 1-1 in NIST Report: 'Best Practices for Reducing the Potential for Progressive Collapse in Buildings' (NISTIR 7396, February 2007) ... showing a bird's eye view of the Disproportionate Damage at Ronan Point, in England, which was caused by a gas explosion in 1968. Click to enlarge.

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Please examine the photograph above.  Ronan Point (later demolished) was a 22 Storey Residential Tower Block in London, England.  In May 1968, this building suffered Disproportionate Damage as a result of a gas explosion.  As is clear from the photograph … it did not Collapse.

Disproportionate Damage

The failure of a building’s structural system:  (i) remote from the scene of an isolated overloading action;  and (ii) to an extent which is not in reasonable proportion to that action.

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Let me now return to the CIB Research WG IV Reflection Document: ‘Structural Reliability & Fire-Induced Progressive Damage’ … where I began by stating …

Fire-Induced Progressive Damage in Buildings is distinguished from Disproportionate Damage – a related but different structural concept – by the mode of damage initiation, not the final condition of building failure.  Until this phenomenon is properly understood, and unless it is impeded, or resisted, by building design … Fire-Induced Progressive Damage will result in Disproportionate Damage … and may lead to a Collapse Level Event (CLE), which is entirely unacceptable to the general population of any community or society.

… and, later in the document, provided this definition …

Fire-Induced Progressive Damage

The sequential growth and intensification of structural deformation and displacement, beyond fire engineering design parameters, and the eventual failure of elements of construction in a building – during a fire and the ‘cooling phase’ afterwards – which, if unchecked, will result in disproportionate damage, and may lead to total building collapse.

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Quickly Concluding …

‘Progressive Collapse’ is not the same as ‘Disproportionate Collapse’ … and while total building collapse may be the condition of final building failure, this will certainly not always be the case.  Therefore … ‘Damage’ is the more correct word to use than ‘Collapse’.

To go even further … it should not be necessary to have to use the word ‘total’ in the first sentence above.

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Reminder … Please Read the Reflection Document …

The purpose of the Reflection Document issued by CIB W14 Research Working Group IV is to examine the ‘hot form’ structural concept of Fire-Induced Progressive Damage, and to propose a critical update to fire engineering design practice.  It is also intended to encourage a wider discussion about some of fire engineering’s fundamental tenets, and the future direction of our profession in a rapidly evolving trans-disciplinary approach to the design, construction and operation of a Safe and Sustainable Built Environment.

Let me repeat again … and as I emphasized in Greece … ALL comments on the Reflection Document are most welcome !

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‘Sustainable Fire Engineering’ – Important Indian Presentation !

2009-09-08:  It is really enjoyable to be back behind my desk, here in Dublin.  Apologies for the prolonged absence.

Since the middle of June last, my travels have taken me to Turkey, France, Italy, the south-west of Ireland to attend my cousin’s wedding in Cork … and back again to Bengaluru (Bangalore) in Southern India to make an important Keynote Presentation at the 2009 Fire & Safety Association of India (FSAI) National Fire Seminar: ‘Engineering a Safe & Secure India’, which was held on Friday, 28th August, at the Leela Palace Hotel.

My Presentation Title & Abstract

Sustainable Fire Engineering: Fire Safety, Protection & Evacuation for All

India, like other economically advanced developing countries, is at an important crossroads.  Difficult, resource-dependent decisions must be made in the next few short years concerning the rapid implementation of a Sustainable Built Environment across a vast country, i.e. one which must serve local needs and meet regional performance requirements during a long life cycle … one which will be adaptable to climate change, variability and extremes … will be in harmony and dynamic balance with the Natural Environment … and, not least, will be super energy-efficient.

Citizens of Developed Nations also have legitimate expectations.  They will express anger when they witness recently constructed buildings in seismic zones collapse, in an earthquake, like a deck of cards (China 2008, Italy 2009) … or they discover that federal/state authorities having jurisdiction, which are funded by their taxes, are ill-prepared to respond effectively to intentional traumatic disruptions to the Social Environment (New York 2001, Mumbai 2008).  Retaining the public’s confidence in national institutions is a fundamental political priority.

In the case of all new High-Rise Buildings, Iconic Buildings, and Buildings of Innovative Design or having a Critical Function … Trans-Disciplinary Building Design Teams must, at a minimum, properly respond to the Recommendations of the 2005 & 2008 NIST(USA) Final Reports on the 9-11 WTC 1, 2, and 7 Collapses.  In practice, the majority of these Recommendations should be applied to the design of all new buildings !

Fire Engineers, competent concerning the processes of ‘real’ building design and construction, must begin to understand the ‘real’ people who occupy or use buildings, every day of every week, in all parts of India … and that they each have widely differing ranges of human abilities and activity limitations.  Just as they are different from each other, they will react differently than expected in a ‘real’ building fire emergency.

Based on a Keynote Presentation before International Council for Building Research (CIB) Working Commission 14 : Fire and Sub-Committee 3 & 4 Members of ISO Technical Committee 92 : Fire Safety, at Lund University in Sweden … and his fire safety texts which have been fully incorporated into International Standard ISO DIS 21542 on Accessibility-for-All, currently under development and due for publication before the end of 2010 … CJ Walsh’s Presentation, at the FSAI National Fire Seminar in Bengaluru, will focus on ‘Fire Safety, Protection & Evacuation for All’.

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