Prescriptive Codes, Performance Based Codes and the Construction Standard of Care after 11 September 2001

Professional Standard of Care  The common law standard of care for performance of design professional (DP) services is generally defined as the ordinary and reasonable care usually exercised by one in that profession, on the same type of project, at the same time and in the same place, under similar circumstances and conditions. Perfect performance is not required by the common law.  Quoted statement from J. Kent Holland, President of the consulting firm, ConstructionRisk, LLC (https://www.constructionrisk.com).

• Article by J. Kent Holland:  Professional Standard of Care
• Article by Zetlin & De Chiara, 2013:  The Construction Standard of Care After 9/11

Prescriptive Codes and Performance Based Codes  Prescriptive Codes provide specific design, construction and maintenance requirements for building, energy conservation, fire prevention, mechanical, electrical, HVAC, plumbing, etc.  Performance Based Codes are those codes which focus on the intent (outcome) and allow the designer, building product manufacturer or contractor to employ the best design, assembly or method to achieve that intent. 

• Examples of Prescriptive Codes are local building and fire codes and the model codes on which they are based (which do NOT have the force of law until adopted at the local level).
• Examples of Performance Based Codes, also known as Outcome Based Codes, are those designs which meet fire safety issues that are not included in Prescriptive Codes.  Performance Based Building Code are a format used by many governments worldwide (eg. the United Kingdom, Australia, Japan, Netherlands, Sweden, and New Zealand).  There is little or no specific language which specifies materials or systems except that the desired outcome must be achieved.  Construction based on Performance Based Codes must deliver the same or similar minimum performance in the built environment as if Prescriptive Codes were followed.
• Article by Vylenis Babrauskas, Fire Science and Technology, 2015:  Performance Based Building Codes – What Will Happen to the Levels of Safety.

Fire Engineering in High Rise Buildings, a presentation by Neal Butterworth, Arup UK, November 2015.

• This article summarizes the strategies used to enhance Life Safety and Fire Safety in high-rise buildings.
• The Passive and Active components and systems used to increase the safety of occupants in high-rise buildings and to decrease the risk of building failure that would endanger the occupants.

High-Rise Fire Safety, Post 9-11-01

In 2006, approximately five years after the events on 11 September 2001, Arthur Cote, then Executive VP and Chief Engineer of NFPA (National Fire Prevention Association, US), gave this presentation at an NFPA Conference in Portugal.  In September 2005, NIST (National Institute of Standards, US) released its report of the National Construction Safety Team on the collapse of the World Trade Center Towers (Draft).  ICC (the International Code Council, US) was preparing changes to the IBC (Int’l Building Code) and IFC (Int’l Fire Code) that were a direct result of the events on 9-11.

This presentation, see the link above, summarizes the elements and redundancy required by NFPA 101 (The Life Safety Code) and the IBC to protect the occupants of high-rise buildings and also in the Means of Egress to insure safe evacuation from the building during emergencies.  There are also elements in this presentation that mention passive and active fire safety (designed to protect the structural elements of the building) and passive and active life safety (designed to help the occupants of the building escape safely during an emergency.  Keep in mind that the Twin Towers of the World Trade Center in NYC were constructed in the late 1960s and opened for occupation in 1973.  Construction and occupant safety requirements for high-rise buildings in the US have changed significantly since then.

The question was asked in this presentation, “Should we design for commercial aircraft flying into a major high-rise building?”.  A dozen years later, NFPA and other organizations worldwide, would begin to investigate high-rise facade fires.  Less than 25 years later, fire and life safety organizations in the US and Europe would begin to question the wisdom of requiring a minimum of two (2) protected exit stairs in low-rise and high-rise residential buildings.

In 2017, after the fire at Grenfell Tower in West London (UK), Douglas Evans made this presentation on facade fires at the International Tall Buildings Fire Safety Conference in London.  Mr. Evans is a Fire Protection Engineer and Consultant for fire safety in the built environment.  He was a Fire Protection Engineer with the Clark County, NV Building Department (US).

This presentation is an excellent overview of past facade fires around the world and summarizes the metal composite materials most responsible for these fires:  High-Rise Facade Fires, A Worldwide Concern  

The 56 page report from the Fire Brigrades Union (FBU, Surrey UK):  The Grenfell Tower Fire – A crime caused by profit and deregulation 

Link to the Fire Protection Association (UK, FPA) response to the Grenfell Tower Inquiry:  Phase 2 Report, September 2024.  Inquiry Phase 2 Report Response.

Link to the Grenfell Tower Inquiry, set up by the Westminster government (UK):  www.GrenfellTowerInquiry.org.uk

• This website contains a summary of the public inquiry into the fire at Grenfell Tower.
• A link to the summary report, Grenfell Tower Inquiry: Phase 2 Report Overview
• A link to the Phase 2 Report, released in September 2024:  Grenfell Tower Inquiry:  Phase 2 Report.  This is the final report, coming seven years after this tragic fire.
• There is also a 45 minute long video and Phase 2 Report summary, Statement from the Panel
• A link to the Phase 1 Report, released in October 2019.  There are also additional videos.  Executive Summary:  Grenfell Tower Inquiry – Phase 1 Report Overview.
• A more recent video summarizing the end of the hearings for Phase 2 of the inquiry, released in November 2022.
• There are additional news, documents and other information associated with the inquiry.

Link to the report, released in June 2019, by International Code Council (ICC) report by Beth Tubbs, Sr Staff Engineer.  Impact of the Grenfell Tower Fire on the US Building Regulatory System.

This report, from FBU, was released in September 2019.  The deadly fire at Grenfell Tower, a high rise residential apartment building in West London, occurred between midnight and 0100 hrs on 14 June 2017.  It burned for 60 hours, 70 people died at the scene from smoke inhalation and fire.  Two additional people died later at the hospital.  More than 70 additional people were injured and 223 people escaped.

The fire was started by an electrical fault in a refrigerator in the kitchen of a flat on the fourth floor.  This spread rapidly up the building’s exterior,  bringing flames and smoke to all residential floors, accelerated by dangerously combustible aluminum composite cladding and external insulation, with an air gap between them enabling the stack effect.

The rapid upward vertical fire spread at Grenfell Tower was primarily due to the presence of a particular kind of cladding: aluminum composite rainscreen cassettes with polyethylene filler material.  There was also an air gap between the cladding and the original exterior surfaces.  This was not the first fire that spread rapidly up, down and around the outside of a high rise building because of the use of flammable aluminum composite cladding.  Similar cladding was used on high rise buildings in other parts of London, the Middle East and Australia.  This was discovered when these several buildings also were destroyed by fast spreading fires.  This problem has happened in renovated existing buildings after the cladding was added to increase the insulation of the original building exterior and to decrease air infiltration around various fenestrations.  This problem has happened in newly constructed high rise buildings when the exterior cladding was added to improve the appearance and soften the corners.

In the US, in 2016, the NFPA Journal published an article that contained a foreboding and sadly prescient statement about the threat posed by combustible exterior wall assemblies.  The concern voiced by Donald Bliss, the author of this report, and other fire professionals around the world – and the primary reason for the increase in high-rise façade fires – was the introduction of combustible materials into these façade systems.

Fires involving the facades of high-rise buildings have been covered by the global media for years. In many of these incidents, spectacular fires have spread up the exteriors of buildings at high speed, engulfing the structures in a matter of minutes. Most of these fires produced few if any fatalities, and as a result much of the world failed to realize the hazard presented by combustible exterior wall assemblies.  Fires that spread on the outside of buildings, feeding off combustible exterior wall assemblies, used to be very rare. Over the last 30 years, however, the number of these fires has increased dramatically. According to research done at Imperial College in London, the frequency of façade fires in large buildings has increased by seven times in the last three decades. Other researchers have identified 59 fires involving external walls on high-rise buildings between 1990 and 2018, with 36 of these occurring since 2010.

This video was created by the Society of Fire Prevention Engineers (SFPE, https://www.sfpe.org/) and was presented at the Tall Building Fire Safety Conference, London, May 2022 (https://www.tallbuildingfiresafety.com/).  Many thanks to Chris Jelenewicz and Russ Timpson!

SFPE released 1st Edition of the, SFPE Engineering Guide:  Fire Safety Guide for Very Tall Buildings, in 2013.  They released the 2nd Edition of the, SFPE Engineering Guide:  Fire Safety Guide for Very Tall Buildings, in 2021.  Both guides are available in various formats from SFPE, Amazon and other sources.

The video is at this link.

9/11. NIST issued their final report, in September 2005, on the collapse of the twin towers of the World Trade Center, NYC, after being struck by airplanes in a horrific terrorist attack. The following article from the NY Times, dated July 2002, does not need illustrations. The writing tells the story.

In addition to the terrible destruction, this article clearly describes a lack of coordination of the first responders – fire, police and Emergency Medical Services. Most problematic were communication systems between the services and absence of command coordination. All the services wanted to help but that resulted in too many people located where they could not best help the occupants of the towers evacuate and protect first responders. Heroes, all.

It may be impossible to coordinate training and the rescue response of the men and women of such a broad mix of emergency services. And, this was an extraordinary tragedy.

FATAL CONFUSION – The NY Times, 7 July 2002