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Winston Churchill Memorial Trust

Structural Safety in High Rise Buildings

By

Lembit Kerks

2012


Lembit Kerks Winston Churchill Fellows Report - 2 -

North America

September – October 2012

New York City

Chicago

Oklahoma City

Los Angeles

San Francisco

Toronto

Supported by

The Fire Service College & Passive Fire Protection

Federation



CONTENTS Page

1 BACKGROUND 6

1.1 Acknowledgements 6

1.2 About the author 7

1.3 The start of my project 7

1.4 The Winston Churchill Memorial Trust 8

1.5 Aims and objectives of my visit 8

1.6 Selection of North American cities to visit 9

1.7 Structure of this report 9

2 BUILDING CONTROL 11

2.1 Building regulation controls in England and Wales 11

2.1.1 Internal fire spread (structure) B3 11

2.1.2 External fire spread B4 12

2.2 Building controls in the USA and Canada 12

2.3 USA building controls 13

2.3.1 Occupancy and construction 13

2.3.2 High Rise buildings 13

2.3.3 Surface linings 13

2.3.4 Fire resistance rated construction 14

2.3.5 Building heights and areas 15

2.3.6 Comparison of USA codes with UK building regulations 15

2.4 Canadian building controls 17

2.5 Enforcement of fire safety 17

2.5.1 Buildings under construction 17

2.5.2 Completion of building work and start of occupation 18

2.6 BTEA ‘Building Trades Employers Association’ in New York 18

2.7 Retrofitting of sprinklers to old buildings 19

2.7.1 New York City 19

2.7.2 Chicago 19

2.7.3 Los Angeles 19

2.7.4 San Francisco 19

2.7.5 Oklahoma City and Toronto 19

2.8 Fire engineered solutions 20

3 DESIGN OF STEEL FRAMED BUILDINGS 21

3.1 Background to steel framed buildings 21

3.1.1 Rigid frame 21

3.1.2 Framed shear truss 22

3.1.3 Framed tube 22

3.1.4 Wind loadings on High Rise buildings 22



CONTENTS (continued) Page

3.1.5 Braced tube 23

3.1.6 Bundled tube 24

3.2 Structural fire protection issues related to observed buildings 24

3.3 680 Folsom Street San Francisco, under construction 25

3.3.1 Outline of construction 25

3.3.2 Fire protection of steelwork 25

3.3.3 Other buildings with similar sprayed fire protection 27

3.4 Roosevelt University Chicago, under construction 28

3.5 AON Center Los Angeles, completed in 1973 31

3.5.1 Fire protection 31

3.5.2 Major fire incident at the building 31

3.6 One Maritime Plaza San Francisco, completed in 1967 32

3.7 John Hancock Tower Chicago, completed in 1970 33

3.8 Willis Tower Chicago, completed in 1973 34

3.9 Empire State Building New York, completed in 1931 34

3.10 Metropolitan Life Tower New York, completed in 1909 35

3.11 Summary of structural steel buildings 35

4 DESIGN OF REINFORCED CONCRETE FRAMED BUILDINGS 37

4.1 Background to reinforced concrete buildings 37

4.2 Trump International Tower Chicago, completed in 2009 37

4.3 Summary Trump International Tower 39

4.4 Devon Energy building Oklahoma City, completed in 2012 41

4.5 Summary Devon Energy Tower 43

5 EARTHQUAKE PROTECTION DESIGN 44

5.1 One Maritime Plaza San Francisco 44

5.2 680 Folsom Street San Francisco 46

6 OTHER BUILDING DESIGN FEATURES 47

6.1 Wall construction (non-loadbearing) 47

6.2 Large floor areas 48

6.3 Glazing systems 49

6.3.1 External glazing 49

6.3.2 Fire resistant glazing 50

6.3.3 Impact resistant glazing 51

6.4 Emergency lighting systems 52

6.5 Atrium design 52

6.6 Helicopter landing decks 53



CONTENTS (continued) Page

7 MISCELLANEOUS BUILDINGS 55

8 OKLAHOMA STATE UNIVERSITY 56

9 FINAL CONCLUSIONS 57

10 NEXT STEPS FOR THE PROJECT 60

APPENDICES

Appendix A References 61

Appendix B List of buildings visited 63

Appendix C WCMT Fellowship timetable – North America 66

Appendix D Press report – Gloucestershire Echo 3 January 2013 67

Press report – Bolton News 22 January 2013 68



1 BACKGROUND

1.1 Acknowledgements

My thanks to the following people who were extremely generous in giving me their time during my

research in North America.

• Richard S Tobin, Assistant Chief of Fire Prevention, Fire Department New York • O’Dell Horton,

Inspector, Fire Department New York • Andrew Dushynskiy, Inspector, Fire Department New York

• John Barrot, Senior Consultant, Arup New York • Jaewook Kwon, Fire Engineer, Arup New York

• Kurt Schebel, Fire Consultant, Arup New York • Steven Pirovolikos, Director of Safety, Structure

Tone Inc. New York • Matthew Ross, Superintendent Project Management & Construction, Lend

Lease New York • Thomas Connors, Executive Director Buildings New York City • Louis J Coletti, CEO

and President, Building Trades Employers Association New York • Carol J Karlin, Fire Safety Academy

New York • Richard C. Ford II, Deputy Fire Commissioner, Chicago Bureau of Fire Prevention • Steve

Johnson, Lieutenant, Chicago Fire Department • John Javorka, Chief Fire Prevention Engineer,

Chicago Fire Prevention Bureau • Chief Peter Van Dorpe, Chicago Fire Academy • Mike Norris,

Captain, Chicago Fire Department • Mark Prestigiacomo, Engineer, Chicago Fire Department • Eddie

Banks, Chicago Fire Department • Pat Mahoney, Assistant Chief Engineer, Trump International

Tower, Chicago • Kellie Sawyers, Deputy Chief/Fire Marshal, Oklahoma • Randy Williams, Captain,

Oklahoma Fire Department • Harold Thompson, Captain, Oklahoma Fire Department • William

McCaine, Captain, Oklahoma Fire Department • Martin Herman, Senior Manager Security, Devon

Energy Corporation, Oklahoma • Ronnie Roberts, Senior Manager, Business Continuity, Devon

Energy Corporation, Oklahoma • Bob Landram, Manager Hines Construction, Oklahoma • Mike Bjes,

Project Manager Holder-Flintco, Oklahoma • Todd Woodward, Senior Project Manager, City Maps

Project Office, Oklahoma • Mark S Beck, OCMAPS Project Office, Oklahoma • JJ Chambless, City

Subdivision & Zoning, Oklahoma • Randy Edwards, Buildings Department, Oklahoma • Craig L.

Hannan, Director, Fire Protection Publications, Oklahoma State University • Michael A Wieder,

Associate Director, Fire Protection Publications, Oklahoma State University • Anthony E Brown,

Associate Professor, Oklahoma State University • Donald l Frazeur, Deputy Chief, Los Angeles Fire

Department • Jaime Moore, Captain, Los Angeles Fire Department • Brian Jones, Captain, High Rise

Unit, Los Angeles Fire Department • Timothy N Kerbrat, Battalion Chief, Los Angeles Fire Department

• Brian McLaughlin, Associate, Arup, Los Angeles • Joseph Gentile, Fire Consultant Arup, Los Angeles

• Ted Moyles, Senior Fire Engineer, Arup, Los Angeles • John A Pattillo, Partner, Conquest Fire Spray,

Los Angeles • Janice Hayes, Captain, San Francisco Fire Department • Frederick E Stumpp, Fire

Protection Engineer, San Francisco Fire Department • Mary M Tse, Lieutenant, San Francisco Fire

Department • Armin Wolski, Associate Principal, Arup, San Francisco • Joe McBride, Chief Engineer,

One Maritime Plaza, San Francisco • Darwin Rodriguez, Superintendent of Construction, 680 Folsom

Street, San Francisco • Jim Fredrickson, Fireproofing Division, LVI Facility Services, San Francisco •

Frank Lamie, Deputy Fire Chief, Toronto Fire Services • Paul Catchpole, Captain, Toronto Fire Service

• Matthew Coombes, Superintendent, EllisDon Building Company, Toronto • Peter Mahut, Property

Manager Brookfield Services, The Palace Pier, Toronto • Darko Patekar, Maintenance Manager

Palace Pier, Toronto • Mike Fletcher, Facilities Manager Pinewood Studios, Toronto • Peter Frith,

General Manager Technical Services, Brookfield Place, Toronto • Philip Longton, Manager Security &

Life Safety Brookfield Place, Toronto • Roderick Blakey, Manager Security & Life Safety, First

Canadian Place, Toronto • William Roussy, Security Supervisor CN Tower, Toronto



1.2 About the author

I am a mechanical engineering graduate of Aston University, and have had a career initially spent in

the process industries, and latterly in fire education and training.

During my time in the food and beverage industry I was a project manager of multi-disciplined

projects for the development of land, buildings and plant.

Over the last 25 years, I have been involved with fire training with the Fire and Rescue Services. I am

an Associate Tutor at the Fire Service College and am involved with fire training at the centralised UK

training establishment in Moreton-in-Marsh, Gloucestershire. Additionally, I have been involved with

university undergraduate education programmes through partnership arrangements between my

college and various UK universities.

My specialism is in building construction topics which are related to fire effects on buildings, building

regulations and general fire engineering subjects. The type of study courses with which I am involved

include fire safety training, fire service operational courses such as ‘Incident Command’ and Urban

Search and Rescue. The later courses have evolved since the ‘Twin Towers’ incident in 2001. I also

deliver similar courses for a wider international market. My personal development over the years

has included becoming a Chartered Member of the Institutions of Mechanical and Fire Engineers and

I have also undertaken a Masters in Building Services Engineering at Brunel University.

1.3 The start of my project

In the early part of 2011, I was asked to present a paper to an ‘International High Rise Symposium’ at

the Fire Service College. The main theme was to focus on fire fighting procedures in High Rise

buildings which was a subject area of great importance to Fire Services worldwide. To widen the

appeal of the symposium and enhance the expertise of presenters, senior fire service

representatives from New York and Toronto were invited to deliver papers.

Concurrently, the UK Fire Services are revising their emergency response procedures at High Rise

incidents and this is likely to continue for some years to come. It is also worthwhile noting the trend



towards the development of ever increasing tall buildings in UK towns and cities. Knowledge and

experience related to their design and construction underpins the ultimate safety of people using

these buildings. This includes safe occupant evacuation and implications to Fire Service personnel

attending emergency incidents.

My particular paper for the symposium was to concentrate on building construction issues related to

High Rise buildings. It became clear to me whilst preparing materials for this presentation that

research of books, journal articles and the internet alone cannot portray a complete story. Although

I had visited two of the UK’s tallest buildings in London, the Canary Wharf and the Gherkin buildings,

I concluded I needed to visit a greater selection of High Rise buildings and much taller ones at that!

Because the development and history of High Rise building began in North America I started to

consider a possible visit there. As I deliberated over the preparation for the symposium I

remembered a conversation I had with a Churchill Fellow some two years before. I particularly

remember I liked the idea of undertaking a research project overseas but at the time could not

identify a suitable project warranting such sponsorship. It was at this point I linked together my need

to study High Rise buildings and the Winston Churchill Memorial Trust Fellowship.

In September of 2011 I duly submitted my application to the Trust and “the rest is history”

1.4 The Winston Churchill Memorial Trust

I would not have been able to undertake this project without the support of the Winston Churchill

Memorial Trust. The esteem in which Winston Churchill is regarded in North America is immense.

Because of this I was able to take advantage of many opportunities and meet people who might not

have otherwise availed themselves to me.

My thanks therefore to all staff at the trust, particularly those I have dealt with, Jamie Balfour, Julia

Weston and Sue Matthews.

1.5 Aims and objectives of my visit

This fellowship was awarded within the category of ‘Education and Vocational Training’ with the

project title ‘Structural Safety in High Rise Buildings’.

The aims and objectives of the project are;

Identify the significant differences in High Rise construction regulations between those of

North America and the UK

Investigate the design issues related to the protection of High Rise buildings against fire,

wind and earthquake

Specifically identify the protection provided to steel and reinforced concrete framed

buildings

Investigate and report on North American construction related to wall and floor

construction, and glazing systems



Develop a collection of photographs of High Rise buildings which would be suitable for

development of Fire Service training courses

Visit Oklahoma State University and view the educational facilities used for fire related

bachelor degree programmes

Improve my personal understanding of the issues related to High Rise buildings with respect

to their design, construction and building use.

1.6 Selection of North American cities to visit

I selected New York City and Chicago because they both have high densities of High Rise buildings.

They are also obvious choices because of the vast array of designs used for both commercial and

residential properties. Architecturally these cities were the foremost leaders in High Rise building

design. Chicago would also be particularly informative with respect to wind design because of its

location on the southern tip of Lake Michigan, a place known for high wind effects and hence known

as ‘The windy city’.

Toronto was included in the itinerary as it has some buildings similar to our own Canary Wharf

development in London albeit much taller.

The west coast including Los Angeles and San Francisco, offers more stringent building designs

against earthquake events due to their location close to the San Andreas Fault Line.

Finally, Oklahoma City offered two important attributes to the study project; the relationship and

impact of tornado events on building design (these are frequent events in this part of North

America); and secondly a visit to Oklahoma State University was considered desirable as it has

successfully run over many years, a ‘Fire Protection and Safety Technology’ Bachelor’s Degree

programme. The University also produces a well-respected ‘Fire Protection Publication’.

1.7 Structure of this report

From my visit to North American I was able to access a total of 22 buildings, as listed in Appendix B.

As expected, the structural forms of these buildings and their respective levels of fire protection

varied enormously. This report is structured as follows;

Section 2 sets the scene and discusses the building regulation controls for High Rise building in

England and Wales, USA and Canada. It concludes with a comparative analysis of the differences

found.

Section 3 discusses the methods used in North America for the protection of steel framed buildings.

Section 4 outlines the methods used for the protection of reinforced concrete framed buildings in

North America.

Section 5 discusses the methods employed to protect High Rise buildings from the effects of an

earthquake.



Section 6 discusses some important building design features observed in High Rise buildings. These

include wall and floor construction, glazing systems, atria designs and the use of helicopter landing

decks.

Section 7 discusses some miscellaneous buildings, observed and photographed, which will be of

value for the development of Fire Service training courses.

Section 8 discusses the visit to Oklahoma State University.

Section 9 discusses the final conclusions from the project.

Section 10 discusses the next steps for this project.

Submitted in appendix C is a copy of the timetable of my visits whilst in North America.

Appendix D contains copies of published reports. They include reports published in the

Gloucestershire Echo on the 3 January 2013, and

Bolton News dated 22 January 2013.



2 BUILDING CONTROL

This section reports on the building regulation controls for England and Wales, USA and Canada.

These include building design issues and enforcement procedures related to control of internal and

external structural requirements. This section concludes with a comparative analysis of the

differences found.

2.1 Building regulation controls in England and Wales

The Building Regulation requirements for fire safety in England and Wales are explained in, Building

Regulations (2000), Approved Document B. For this project High Rise buildings have been considered

as those with a greater height than 30m (98.4ft), and specifically with building uses (purpose groups)

of 2b Hotels, 1a Flats, and 3 Offices. Two particular parts of these regulations are relevant to this

project.

2.1.1 Internal fire spread (structure) B3

The regulations state “buildings shall be designed and constructed so that, in the event of a fire, the

stability will be maintained for a reasonable period.” To achieve this, building designs are centred on

either or both of the following;

(a) Sub-division of a building with fire-resisting construction;

(b) Installation of suitable automatic fire suppression systems.”

Further, the regulations indicate the safety requirements for High Rise buildings include the

following designs features;

All structural frame elements require protection of 2 hours fire resistance; reference BS 476-

parts 20-24:1987.

All floors need to be compartment floor of 2 hours fire resistance; however these can be

reduced to 90 minutes for elements not forming part of the structural frame.

All shaft openings i.e. staircases and service shafts, require wall enclosures of 2 hours fire

resistance; however these can be reduced to 90 minutes for elements not forming part of

the structural frame.

Fire resistance ratings for fire doors are selected from Table B1 of the regulations, resulting

in FD30S (30 min fire resisting), reference BS 476 part 22, or half the appropriate rating of

the wall it is fitted in, dependent upon application.

Floor plate areas can be unlimited.

Flats and Office use buildings require sprinkler protection throughout.

Hotel buildings have no requirements for sprinkler protection.

Fire fighting shafts will be required complete with fire fighting lifts, with lobby access on

each storey and with all walls of 2 hours fire resistance. A minimum of 2 such shafts will be

required, assuming large floor plate areas. Maximum hose lengths of 60m (197ft) to water

outlet connections for buildings with sprinklers, and 45m (148ft) for buildings without

sprinklers. Wet main raisers are required for buildings greater than 50m (164ft) in height.



Note: The fire resistance ratings are referenced to BS 476 parts 20-24 fire tests on building materials

and structures.

Most importantly, all buildings within the scope of this project “Shall be designed and constructed so

that the unseen spread of fire and smoke within concealed spaces in its structure and fabric is

inhibited.” To satisfy this part of the regulations all raised floors and suspended ceiling void spaces,

greater than specific areas, require fire protection. Cavity barriers are typical forms of protection

which reduce the void space areas and therefore restrict the potential for fire spread.

2.1.2 External fire spread B4

This part of the regulations states “The external walls of a building shall adequately resist the spread

of fire over the walls and from one building to another, having regard to the height, use and position

of the building.”

For buildings with a boundary distance greater than 1m (3.3ft) the external walls require a nominal

surface control, fire propagation index I, reference BS 476 part 6, of not greater than 20, for walls up

to 18m (59ft). A higher control standard of Class O surface spread of flame, reference BS 476 parts 4,

6, 7, 11, is required on external wall heights greater than 18m (59ft). If boundary distances are less

than 1m (3.3ft) then the higher control standard of Class O is required.

To resist fire spread from one building to another controls are placed on unprotected openings, e.g.

windows and doors, in relation to the boundary distance from each external wall. In effect, because

High Rise buildings will be compartmented floor by floor, a high degree of unprotected openings are

allowed. Allowable unprotected areas in walls increases with boundary distance, providing a

minimum of 1m (3.3ft) boundary distance is available. This allows the designer to build external

walls in glazing materials without too many restrictions.

2.2 Building controls in the USA and Canada

Some time ago, both the USA and Canada consolidated a multiplicity of buildings codes used in their

countries through the International Code Council (ICC). This resulted in a common International

Building Code (IBC) being used throughout North America, which regulates the construction and

renovation of buildings. Additionally each city and town has a zoning ordinance which regulates

what can be built where, and how a building can be used. Both these regulated documents need to

be complied with, prior to approval of any building work.

The IBC building codes also make further references to ASTM (American Society for Testing and

Materials) and NFPA (National Fire Protection Association) standards. For example ASTM standards

are used for fire testing of materials and elements of construction, and NFPA standards are used for

automatic sprinkler installations.

The IBC code should be viewed as an equivalent status to UK regulations and should be treated as a

minimum standard. Each State in the US or Province in Canada, can amend the technical content in

the code as can the major cities. The amendments usually require additional technical requirements.



For example New York City, with high density High Rise buildings, would have more demanding

requirements than New York State which is mainly rural.

2.3 USA building controls

With reference to structural safety related to High Rise Buildings, four chapters of the IBC codes

have particular relevance to structural design. They are;

2.3.1 Occupancy and Construction

As with many countries, the essence of regulatory safeguards from fire was to provide reasonable

levels of property protection. Thus, if property was adequately protected from fire, then the building

occupants would also be protected. The IBC codes have now evolved with the concept of equivalent

risk. This concept maintains an acceptable level of risk against the damages of fire, respective to a

particular occupancy type or group. It can be achieved by limiting the height and area of buildings

containing such occupancies according to the building’s construction type, (its fire endurance).

The whole built environment is therefore grouped into 10 occupancy uses classified by letter

designations, in comparison with the 7 UK purpose groups. High hazard, educational and

miscellaneous buildings are additionally designated in the US with appropriate design requirements.

To complicate matters the lettering systems vary across the cities of North America.

New York’s designation of relevant building groups is;

Table 1 IBC Occupancy groupings with designations for New York City

Building Occupancy Designation

Residential Hotels R1

Residential Apartments R2

Business Offices B

2.3.2 High Rise Buildings

Buildings with an occupied floor at a greater height than 23m (75ft) are classified as High Rise

buildings, compared with 30m (98.4ft) in the UK. An important safety design feature for all newly

built hotels, apartments, and office buildings is the compulsory requirement to fit automatic

sprinklers throughout the building. As would be expected, all such High Rise buildings also require

automatic fire alarm systems, emergency voice/alarm and communications systems, fire department

communication systems, a fire command centre and elevators complete with lobby approach.

2.3.3 Surface linings

Surface linings in buildings are controlled by ASTM E84 fire tests including smoke emission from

materials. These controls have been considered equivalent to UK provisions for the purposes of this

project.



2.3.4 Fire resistance rated construction

The IBC code classifies buildings into 5 types of construction according to the proposed selection of

construction materials. This classification accounts for the response of a building in fire conditions as

a result of its occupancy or fire load. Each type of construction is then provided with a minimum

hourly fire resistance rating for the structural elements. However, this issue is simplified because

only non-combustible forms of construction are selected for elements of construction for High Rise

buildings throughout North America. Therefore the only relevant type of construction is Type 1A.

Fire resistance testing is undertaken according to ASTM E119, in which the test regime measures the

structural integrity of elements of construction and materials. Further the test takes into account

three important criteria; transmission of heat, transmission of hot gases through the element, and

the load carrying capacity for the duration of the test. Additionally, for walls and partitions, rated at

1hr or above, a hose stream test according to ASTM E2226 is applied to the element of construction.

This added test is used to monitor the cooling impact and to measure the resistance to

disintegration under adverse conditions. It is particularly relevant for the use of glass and glazing

systems in wall and partition elements. Further it can be concluded that wired glass is generally used

in North America because many alternative glasses fail the hose stream test. The hose stream test is

not used in the UK. The relevant fire-resistance requirements for structural elements are, reference

Table 2.

Table 2 IBC fire resistance requirements for elements of structure

Element of Structure Fire Resistance Rating

Structural frame 3hrs

Bearing walls external and internal 3hrs

Floor construction including supporting beams and joists 2hrs

Roof construction 1.5hrs

Note: The IBC code does not specify requirements to protect void spaces above suspended ceilings

or below raised floors in High Rise buildings. Therefore the use of cavity barriers is limited. However,

fire stopping is specified which is very much in line with UK practice.

As in the UK the fire resistance ratings for external walls is based on fire separation distance of the

external wall from the boundary. The IBC code fire resistance ratings for external walls for hotels,

apartments, and office buildings are, reference Table 3.



Table 3 IBC Space separation of buildings related to required fire resistance of external walls

Space Separation Fire Resistance Rating

Less than 9.1m (30ft) 1hr

9.1m (30ft) or greater 0

IBC code fire resistance requirements for openings including fire doors and shutters are, reference

Table 4.

Table 4 IBC code building openings related to fire resistance requirements

Opening assembly description Fire Resistance Rating

Walls and fire barriers of 3hrs 3hrs protection

Walls and fire barriers of 2hrs 1.5hrs

Walls and fire barriers of 1.5hrs 1.5hrs

Shaft fire barriers requiring 1hr 1hrs

Other fire barriers requiring 1hr 0.75hrs

Fire partitions corridor walls 1hr 0.75hrs

2.3.5 Building heights and areas

Floor area requirements are relatively simple to apply because unlimited floor areas are permitted

for High Rise buildings used for hotels, apartments, and office use, similar to the UK.

2.3.6 Comparison of USA codes with UK building regulations

Tables 5, 6 and 7 illustrate the comparative differences between the USA, IBC codes and UK

regulations for building use/occupancy, fire resistance ratings for elements of structure and

requirements for sprinkler protection.

Table 5 Occupancy classifications related to USA, IBC codes and the UK regulations

Occupancy classification USA, IBC UK

Residential Hotel R1 Purpose Group 2b

Residential Apartments R2 Purpose Group 1a

Business Offices B Purpose Group 3



Table 6 Fire resistance ratings for building elements related to USA, IBC codes and UK regulations

Building Element/Fire resistance USA, IBC UK

Fire resistance rating Fire resistance rating

Structural Frame 3hrs fire resistance 2hrs fire resistance

Floors 2hrs fire resistance 1.5hrs fire resistance

Roof construction 1.5hrs fire resistance 0

Shaft barriers 2hrs fire resistance 1.5hrs fire resistance

Fire doors/shutters in fire walls 1-3hrs fire resistance 1.5hrs fire resistance

Fire doors/shutters in shafts 1-3hrs fire resistance 0.5-0.75hrs fire resistance

Fire doors in escape routes 0.75hrs fire resistance 0.33-0.5hrs fire resistance

Fire fighting shafts N/A 2hrs fire resistance

Increased levels of fire resistance for elements of structure, reference Table 6, are required in the

USA in terms of;

Structural frames, increase of 1hr.

Floor construction, increase 0.5hr.

Shaft barriers have an increase of 0.5hr, and also are required to be impact resistant.

Fire doors and shutters built into fire walls are far more substantially constructed with up to

double the fire resistance requirements of the UK.

Fire doors and shutters built into escape routes are of 45min fire resistance compared with

20/30min fire doors in the UK.

Roof construction requires 1.5hrs with no controls in the UK

Fire fighting shafts in the USA are not designed as such. Fire resisting barriers to shafts are

provided and are likely to be of a higher rating than in the UK.

Table 7 Sprinkler requirements for occupancy classification related to USA, IBC codes and UK

regulations

Occupancy classification US, IBC UK

/Sprinkler requirements Sprinkler requirements Sprinkler requirements

Residential Hotel Required N/A

Residential Apartments Required Required

Business Offices Required Required

It is a compulsory requirement in the USA for new High Rise buildings to be fitted with sprinklers, as

it is in the UK. However it is noticeable that UK hotel buildings are an exception and do not require

sprinkler protection. Presumably the UK argument is centred on the fact that hotel construction is in

small cells (bedrooms) and therefore the fire resistance ratings of fire barriers are adequate to

prevent fire spread. From observations of hotel buildings in North America, design layouts do



include commercial (restaurants) and assembly (spa facilities) areas positioned at high levels within

buildings. These areas with increased fire loads and larger floor areas would challenge the wisdom of

not regulating sprinkler protection for High Rise hotel buildings in the UK.

2.4 Canadian building controls

The relevant building codes for Toronto are;

‘Ontario Building Act 1992’ made effective through S.O. 1992 Chapter 23 of 1 June 2011. Specifically

part ‘Ontario Regulation 350/06’ (Division B – Acceptable Solutions) which is enforced by the

Building Control Department. The under-pinning background to the building code comes from the

IBC code with specific amendments adopted by Ontario and Toronto. The comparative differences

between this code and the UK are similar to those discussed for the USA, however with one notable

exception. The maximum fire resistance rating for elements of structure is 2hrs, which is similar to

the UK. Fire sprinkler requirements are the same as the USA.

‘Fire Protection and Prevention Act 1997’ made effective through ‘Ontario Regulation 213/07’,

specifies fire code requirements and is enforced by the Fire Services. These regulations are used for

on-going fire safety of buildings during occupation.

2.5 Enforcement of fire safety

2.5.1 Buildings under construction.

For the six North American cities visited, the fire safety enforcement requirements for buildings

under construction varied.

Fire safety enforcement with respect to compliance of building work to building codes is solely

undertaken by the buildings department in the cities of Los Angeles, San Francisco and Toronto.

Consultation processes do exist between departments, but the fire departments do not have any

enforcing powers.

Conversely, in the cities of New York, Chicago and Oklahoma the fire departments do have

enforcement powers, complete with violation penalty notice systems. Major fire safety issues are

controlled by the fire department. These are; storage of combustible building materials, hot working

permit systems, and provisions of water supplies to standpipes and wet mains in buildings whilst

under construction. For example fire water mains are required to be fitted up to the floor below the

construction working floor, complete with valves in readiness for fire fighting on the construction

site. In New York these water mains are required to be pressurised with air complete with an

inspection air gauge at a site entry point. Regular inspections are made to safeguard critical fire

protection systems and safe working practices.

In the UK, fire services do not have enforcement powers whilst a building is under construction. Fire

safety designs to meet building regulation requirements are enforced by the building control

authorities. Safe working practices during construction are enforceable by the Health and Safety



Inspectorate. Fire Services may be asked to advise on fire safety matters during construction

however this is undertaken on a goodwill basis only.

2.5.2 Completion of building work and start of occupation.

When construction work on buildings is complete and occupation takes place, all six cities have fire

codes which authorises fire departments to inspect buildings with respect to fire safety matters. The

fire departments become the lead authority in implementing on-going fire safety. To assist the fire

departments in these duties enforcement powers are granted to them. Some of the US cities also

have violation penalty notice systems granted to them. For High Rise buildings the owner/occupier is

expected to have a ‘Fire Safety Plan’ and an ‘Emergency Action Plan’.

2.6 BTEA ‘Building Trades Employers Association’ in New York

Following several major incidents in New York City, Mayor Bloomberg instigated the setting up of

the BTEA organisation and supported by a Fire Safety Academy for the building trades in the city. As

the construction industry is a multi-billion dollar one and is critical to the development of economic

prosperity in New York, maximum support was given to the industry. The major incidents were:

On the 18 August 2007, the Deutsche Bank fire which occurred during the deconstruction phase of

the building. It suffered a fire caused by workers smoking carelessly, and in violation of the buildings

safety code. The building did not have a functioning water standpipe resulting in the fire spreading

over 10 floors. The fire killed two fire fighters and injured more than 100 fire fighters.

In March 2008 at East 51st Street, a crane jib snapped and fell off resulting in 7 people being killed,

and another crane collapse incident at Upper East Side in May 2008 resulted in 2 people being killed.

It was a great pleasure for me to meet with the President and CEO of the BTEA, Louis J Coletti

together with the Assistant Chief Fire Officer for Fire Prevention Richard Tobin. The progress made

by the BTEA in getting the general construction safety and particularly the fire safety messages over

to construction workers has been outstanding. Progress has been made by coordinating all the

agencies involved in construction, including buildings and fire departments of the city with

contractors. They are now in a position that all construction trades working in the city, fully

participate with safety training days and it is undertaken in a proactive manner by all. When

important information is published, such as dates for safety training or accident and violation

statistics, all trade organisations and individuals are notified accordingly. Meetings take place every

month and major decisions, made at the BTEA, are published widely.

To support the BTEA a Fire Safety Academy has been set up and is supported with finance to the

tune of $1m per year. The fire department of New York fully supports this activity and regularly gives

guidance and talks to construction workers. The support for this activity comes directly from the top

of the organisation via Richard Tobin the Assistant Chief Officer of Fire Prevention.



2.7 Retrofitting of sprinklers to older buildings

Today, sprinklers are a requirement for High Rise buildings throughout North America. However this

has not always been the case. The building codes have developed over the years and fire sprinklers

have been added to the overall safety designs of buildings. The phasing-in of sprinklers and the time

given for owner/occupiers to fit them retrospectively varies across the continent. Much political

debate at city level takes place before implementing retrospective building requirements. Below is a

review of the status for the 6 cities visited.

2.7.1 New York City

All commercial buildings, including offices, not fitted with sprinklers require retrofit sprinklers.

Because these buildings are of a commercial nature the city expects companies to afford the

alteration works. Similar arrangements are required for residential buildings but there are many

exceptions. These exceptions are assessed on individual building safety merits. The use of asbestos

insulation is a significant one which might preclude a building from this conversion. A clean-up

operation would be difficult to achieve if the insulation was disturbed. Overall a completion period

of 10 years was granted for the retrofitting of sprinkler installations.

2.7.2 Chicago

Similar arrangements are in place with Chicago in that all High Rise commercial and residential

buildings without sprinklers require retrofit installations. This only affects some buildings built prior

to 1975. A period of time was granted to owner/occupiers of such buildings with completion

expected during 2013-2017. There are some 200 buildings in this category.

2.7.3 Los Angeles

All commercial buildings without sprinklers require retrofit sprinkler installations. This only affects

buildings pre-dating 1974 and again a 10 year completion period was granted to building owners.

Similarly residential buildings without sprinklers require retrofit sprinklers if building owners intend

undertaking structural building alterations. Under these conditions sprinklers are only required in

the communal areas of the building and not the main accommodation spaces. Asbestos insulation is

a significant feature affecting residential buildings.

2.7.4 San Francisco

All commercial buildings built without sprinklers require retrofit sprinkler installations. This affects

buildings built prior to 1994. 12 years were granted for the completion of these building works.

Hotel buildings had to comply with retrospective fitting of sprinklers whilst apartment buildings

were excluded. Historic buildings were also exempted from these requirements.

2.7.5 Oklahoma City and Toronto

The city authorities have not implemented any rules for the retrofitting of sprinklers to any type of

building.



2.8 Fire engineered solutions

Fire engineered solutions are acceptable in North America. However, non-compliance with clauses in

city building codes is closely scrutinised. Sometimes fire engineering consulting companies carry out

third party evaluations of schemes on behalf of the authorities and paid for by the proposed

developer.



3 DESIGN OF STEEL FRAMED BUILDINGS

This section reports on and discusses the styles of structural steel frames used in North America

including the effects of wind loadings on the structure. It continues with the methods used to

protect steelwork against fire complete with illustrative case studies. The section is concluded with a

summary of buildings visited related to their appropriate protection.

3.1 Background to steel framed buildings

Economics and the limitations of masonry construction dictated the early development of High Rise

buildings. The result was the emergence of iron/steel frame structures which minimised the depth

and width of structural members at building perimeters. Consequently, the larger openings were

filled with transparent glasses, while the iron/steel structures were clad with other solid materials

such as brick or terra cotta. These cladding materials did not carry any loads from the buildings

except their own weights and the lateral wind pressures. Later a new cladding concept “curtain

walling”, which allowed external glass panels to be hung from buildings, was developed with the

emergence of new structural systems, reference Mir M Ali and Kyoung Sun Moon (2007). Now-a-

days we classify steel framed buildings into the following generic structural systems as shown in

Figure 1.

Figure 1 Classification of High Rise (structural steel) systems related to storey heights,

reference, Mir M Ali and Kyoung Sun Moon (2007)

During my visit to North America the following five styles of steel frame structures were observed;

3.1.1 Rigid frame

These buildings consist of vertical columns and horizontal joist members rigidly connected together

in a grid form. The size of columns is controlled by gravity loads that increase towards the base of

the building giving rise to larger column sizes towards the base from the roof. The size of horizontal



joists is controlled by the stiffness of the frame in order to ensure acceptable lateral sway of the

building.

Many High Rise buildings of this form of construction were observed, with most less than 30 stories

tall. Of particular note were the older buildings including, the Fuller Flatiron (22 floors) built in 1902,

and the Metropolitan Life Tower (45 floors) built in 1909, both located in New York. More modern

versions of this form of structure were observed at 680 Folsom Street in San Francisco (14 floors)

which is currently under construction.

3.1.2 Framed shear truss

These buildings are similar to rigid frame structures, with additional shear truss frame interacting

systems. Lateral loads are resisted mainly through axial stiffness of the frame members. The position

of the bracing in the building varies and because of this internal planning space may be limited due

to the shear trusses.

New York’s Empire State building (102 floors) completed in 1931 is a good example of this form of

structure.

3.1.3 Framed tube

When buildings are designed taller, the perimeter becomes structurally more significant. They

become more vulnerable to lateral forces, especially wind loads. Framed tubes are used to

counteract these forces by stiffening the external perimeter and rigidly connecting the external

frame. This comprises closely spaced columns with deep spandrel beams. A major disadvantage with

this form of design is the obstruction of views from the building, due to the close spacing of external

column members.

The Aon building in Los Angeles (62 floors) built in 1973 typifies this form of structure.

3.1.4 Wind loadings on High Rise buildings

Figure 2 shows the major forces exerted on a High Rise building caused by wind conditions, including

forces from the wind direction, cross-wind and resulting torsional twisting. Cross winds are

significant because they can be greater than the forces applied directly from the wind direction.

Wind flow patterns generated around buildings is complicated by distortion of the mean flow,

separation flow, formation of vortices and the development of the wake. Wind pressure fluctuations

on the building façade results in vibrating forces which further complicates the structural analysis.



Figure 2 Diagram showing the forces acting Figure 3 Computer model of wind effects on

on a building caused by wind effects reference, buildings reference,

Mendis P, Ngo T, Haritos N, Hira A (2007) Mendis P, Ngo T, Haritos N, Hira A (2007)

Figure 3 shows computer simulated wind effects on High Rise buildings, complete with eddy current

flow paths. These create negative pressure areas around the building thus setting up the three main

component forces acting on the building. Vortex shedding causes cross wind forces and if the

structure is flexible, these forces cause oscillation. Further, if the vortex shedding frequency

coincides with the natural frequency of the building, failure can occur.

3.1.5 Braced tube

Braced tubes are a variation of the framed tube. Wider columns are used with further diagonal cross

bracing which stiffens the columns to create wall-like characteristics, thus eliminating the use of

closely spaced vertical columns. The diagonal bracing carries gravity loads and acts as inclined

columns.

Figure 4 One Maritime Plaza San Francisco, Figure 5 John Hancock building Chicago,

with external cross bracing with external cross bracing



One Maritime Plaza in San Francisco (27 floors) built in 1967, and the John Hancock building in

Chicago (100 floors) built in 1970, see Figures 4 and 5 respectively, are good examples of this form of

structure.

3.1.6 Bundled tube

A bundled tube is a cluster of individual tubes connected together to act as a single unit. I was able

to visit the world’s first bundled tube building, the Willis Tower in Chicago (110 floors) built in 1973.

This building has nine steel framed tubes bundled together at the base, some of which terminate at

various levels along the building height with two tubes continuing between the 90th floor and the

roof, as illustrated in Figure 6 and 7.

Figures 6 Structural steel ‘Bundled tube’ Figures 7 Structural steel ‘Bundled tube’

Willis Tower building Chicago Willis Tower building Chicago

reference, Mir M Ali and Kyoung Sun Moon (2007)

3.2 Structural fire protection issues related to observed buildings

Structural steel offers many advantages to the building designer including controlled manufacture of

component parts fabricated in the factory followed by site erection. However, steel does have a

major weakness from a fire perspective. Steel strength is dramatically reduced at relatively low

temperatures e.g. it loses half its strength at approximately 5500C. It is therefore important to fire

protect structural steel from fire.

In North America the majority of fire protection applied to steel framed buildings is by cement

sprays. Programmed installation schedules allow for preparation time to seal a floor, spraying time

to protect the steelwork, and time for clean-up operations. During this time other trades do not

undertake any building work within the vicinity of spraying. In the UK, cladding systems as well as

cement spray protection is used. Cladding systems alleviate safety and environmental issues



associated with dusty cement spraying operations. Cladding systems are however used in North

American but only when high quality smooth surface finishes are required.

The design process for steelwork protection includes the architect selecting the cement spraying

process and specifying the fire resistance ratings for elements of structure, with the developers and

fire protection contracting companies marking up drawings and identifying spray coating thicknesses

to specific elements of structure. A good example to illustrate this is the construction works

witnessed at 680 Folsom Street, San Francisco.

3.3 680 Folsom Street San Francisco, under construction

3.3.1 Outline of construction

Alterations to this 14 storey building included, stripping the building back to a bare shell, adding 2

extra floors and extending the floor areas, reference Figure 8. The building is a rigid steel frame with

some exterior vertical supports with composite steel deck floors. Figure 9, illustrates the top side

view of a typical floor section prior to concrete pouring. The floor comprises; a profiled steel deck,

shear studs (right hand side of the photograph), and steel reinforcement bars.

Figure 8 14 storey building with 2 added Figure 9 Typical floor construction

Floors and extended floor areas

3.3.2 Fire protection of steelwork

The architect specified the construction as a type 1A building and identified the fire resistance

ratings for the elements of structure as shown in Table 8. The ratings are in-line with IBC code

requirements as discussed in section 2.3 of this report.



Table 8 Architect specified fire resistance ratings for elements of structure.

Element of structure Fire resistance rating

Column protection 3hrs fire resistance

Floor primary beams 2hrs

Floor secondary beams 2hrs

Floor deck 2hrs

The method of achieving the required fire resistance by cement spraying was drawn up by the

specialist fire protection contractor. The material used was CAFCO 300, fire tested for use in North

America to ASTM E119 (also suitable in the UK to meet BS 476 part 21 requirements). The specialist

fire protection company supplied drawings indicating material thicknesses for specified elements.

Figure 10 illustrates a typical floor plan with spray coating thicknesses for specified elements.

Differing colours are used to represent material spray thicknesses of; yellow 15/16in (24mm),

orange 1 1/16in (27mm), green 1 1/8in (29mm), purple 1 5/16in (33mm), blue 1 1/2in (38mm), and

chain dot purple 1 11/16in (43mm).

Figure 10 Typical floor plan identifying spray protection thicknesses to elements of structure

With respect to the extent of fire protection of the structural steelwork, the architect specified all

columns and beams to be cement spray protected. The composite floor structures throughout the

building are inherently of 2hrs fire resistance, therefore spraying of the underside of the floor deck

was not required. Factors which influence the fire resistance of the composite floors is; the

composite nature of the structure including the deck profile, the concrete mix used, and the

thickness of floor.

The preparation undertaken prior to spray protection is illustrated in; Figure 11, spray cleaning of

the existing and new steelwork, and Figure 12, fixing metal laths to improve fire protection spray

adhesion to the structure.



Figure 11 Cleaning the structure prior to Figure 12 Fixing of metal laths to improve

fire protection spraying adhesion of fire protection spray

Finally, application of fire protection spraying is shown in Figure 13. The extent of fire protection

includes spray application to all columns and beams and with the underside of the floor left

unprotected, as can be seen in Figure 14.

Figure 13 Application of fire protection sprays Figure 14 Extent of spray application

including all columns and beams and with

the underside of the floor unprotected

3.3.3 Other buildings with similar sprayed fire protection

The following buildings are further examples were cement spray protection was used for the

structural frame with all columns and beams protected, and with the underside of the composite

floor unprotected.



The Bank of Montreal Offices, Toronto completed in 1975

Brookfied Place, Toronto completed in 1992

Constellation Place, Los Angeles completed in 2003

Figures 15, 16 and 17 illustrate the extent of applied fire protection.

Figure 15 Bank of Montreal Office, Toronto Figure 16 Brookfield Place, Toronto

Figure 17 Constellation Place, Los Angeles

3.4 Roosevelt University Chicago, under construction

Figure 18 All columns and beams fire protected Figure 19 Underside of decking unprotected

I visited a new development for an indoor athletics facility at Roosevelt University. This three storey

building with a large foot print area is classified as assembly occupancy. The structural steel frame



was fire protected with cement spray applied to all columns and beams, reference Figure 18. The

underside of the composite deck floor was left unprotected, reference Figure 19.

From the architects drawings I was able to cross reference the fire protection designs for elements

of structure to the UL (Underwriters Laboratories) specifications presented in the “Fire Protection

Schedule” for the building, reference Table 9. The specifications related to elements of structure

shown in Figures 18 and 19 are;

Columns – 3hrs fire resistance to UL X764, reference item 1 in Table 9. The approved companies

referred to in the UL listings included, Isolatek International, Newkem Products Corp, Luck Core

Insulating Materials and Manufacturing LLC. Materials and spray thicknesses are quoted in the

specifications. UL X752 specifies the requirements for box section columns.

Beams supporting composite floors – 2hrs fire resistance to UL D739. A comprehensive UL list of

approved companies is quoted for all component parts of the beam and floor structure. Composite

floors, constructed as per item 4 in Table 9, provide 2hrs fire resistance without fire protection to

the underside of the floor reference, UL D739.

Of great interest in the design of this building was the fire protection of a hidden structural column

which could not be sprayed with cement materials as location access was prohibitive. The fire

resistance rating was to be 3hrs. To overcome this difficulty the column was coated with

intumescent materials at the factory and fitted on site. The fire protection schedule specifies the use

of UL X650 specifications with Isolatex International as the approved UL listed company.

Throughout my visits I did not come across any other applications using intumescent coatings, which

surprised me as we frequently use them in the UK. Construction professionals in North America

were well aware of intumescent coating products and have occasionally used them but only as

special applications when cement spray or fire board cladding is difficult.

Whilst studying the UL listings for this building, I did come across specification UL XR622. The only

approved company for this specification is Leigh’s Paints, a UK manufacturer. The specified product

was Firetex M90 or M90TH, rated up to 2 1/2hrs fire resistance.



Table 9 Architects specified fire resistance ratings for elements of structure with design specifications

for UL (Underwriters Laboratories) designations



3.5 AON Center Los Angeles, completed in 1973

3.5.1 Fire protection

The process of fire design for this building was undertaken in a similar way to that previously

discussed. However the conclusions reached were somewhat different. The steel framed structure is

of a framed truss comprising composite floors. All columns and beams are spray protected including

the underside of the floor, reference Figures 20 and 21. The cement spray protection used was

supplied by Monokote.

Figure 20 Fire protection spray to Figure 21 Fire protection to

all columns and beams underside of all floors

The reason for fire protecting all steelwork including the underside of the floor, in what appears to

be over engineered fire protection, can probably be explained by three factors. These are, higher fire

resistance requirement in the USA, shallower profile of the steel decking, and the custom and

practices in the USA at the time of building. More recent USA buildings appear to be designed more

in-line with UK building practices.

Interestingly in Los Angeles, it is a building code requirement that all staircases are pressurised and

all have lobby approach to accommodation floors.

3.5.2 Major fire incident at the building

However it is important to note that this particular building suffered a serious fire on the 4 May

1988, in which one maintenance worker died and 40 others were injured. The building at the time

was owned by the First Interstate Bank. Fire started on the 12th floor and spread to the 16th floor

eventually destroying 4 floors and partially affecting another. It burned for 3 ¾ hours before it was

brought under control. Sprinklers were being installed in the building (installation 90% complete) at

the time of the fire however they had not been connected to water supplies. Perhaps it can be

argued that fire protection of the steel frame and the underside of floors is an appropriate form of

protection, albeit providing a further degree of property protection over and above UK regulated life



safety provisions. Lack of fire sprinklers was obviously an important omission from the overall safety

components of the building’s safety systems. Figure 22 shows the building during the fire incident.

Figure 22 First Interstate building on 4 May 1988

Photograph by Boris Yaro of the Los Angeles Times

3.6 One Maritime Plaza San Francisco, completed in 1967

This building is of structural braced tube design. The external frame with diagonal members carries

gravity loads of the building, reference Figure 23. The structural steel external frame is fire protected

with encased concrete surrounding the frame members and is finished with decorative aluminium

sheeting see Figure 24.

Figure 23 Structural steel braced tube design Figure 24 External frame members

encased in concrete



The structural steel fire protection employed in this building includes cement spray protection

(supplied by Monokote) of all columns, beams and the underside of the composite floor, reference

Figures 25 and 26.

Figure 25 Cement spray protection of the Figure 26 Cement spray protection of beams

underside of the composite floor deck connecting through to the external frame

which is encased in concrete

3.7 John Hancock Tower Chicago, completed in 1970

This building is of structural braced tube design similar to One Maritime Plaza. Again the external

frame with diagonal members carries gravity loads of the building. The structural steel external

frame is fire protected with encased concrete surrounding the frame members and is finished with

decorative aluminium sheeting, reference Figures 27 and 28. The internal structural fire protection

includes spray protection of all columns, beams and underside of floors, reference Figures 29 and 30.

Figure 27 John Hancock building Chicago Figure 28 External columns, beams and

diagonal bracing encased in concrete



Figure 29 Cement spray protection of columns Figure 30 Cement spray protection of beams

And underside of floor

3.8 Willis Tower Chicago, completed in 1973

This building is of a bundled tube design. The structural fire protection comprises spray protection

applied to all steel elements including columns, beams and floor components similar to the buildings

discussed in sections 3.5, 3.6 and 3.7.

3.9 Empire State Building New York, completed in 1931

The building is of 102 floors and the structure comprises steel shear trusses and hinged frames. At

the time it was the tallest building in the world and remained so for forty years. The fire protection

of the structure is of concrete encased columns, beams and reinforced poured concrete floors,

reference Figures 31 and 32. It is interesting to note the concrete cover to columns is 8in (203mm)

thick.

Figure 31 Empire State building, New York Figure 32 Concrete encased beams with reinforced

concrete floors



The building is in the process of being completely up dated. The external facades have recently been

renovated, leaving a multi-million dollar project for the upgrade of the internal parts of the building.

Currently, there is no sprinkler protection in the building but it is scheduled to have them fitted

during the next stage of building works.

3.10 Metropolitan Life Tower New York, completed in 1909

This listed historic building has 45 storeys. It was built for offices and has been used as such up until

recent years, reference Figure 33. It is currently unoccupied awaiting alterations for a change of use

to an up market, five star hotel. The building is of a rigid steel frame structure with concrete encased

columns and beams, which provides the required level of fire resistance, reference Figure 34. Barrel

arched floors complete the structure. The fire protection to the floors is achieved from the ash

concrete materials used in construction, reference Figure 35.

Figure 33 Metropolitan Life building Figure 34 Concrete encased columns and beams

New York

Figure 35 Barrel arched floors with concrete ash providing fire protection

3.11 Summary of structural steel buildings

Table 10 lists the structural steel buildings visited and highlights their type of building structure with

forms of fire protection used.



Table 10 Structural steel buildings related to type of structure, form of fire protection, together with

occupancy use, number of floors, and date of completion of building.

Building Type of Fire Protection Use Floors Completion

Structure

Metropolitan Rigid Frame Concrete encased columns and Office 45 1909 Life Tower

beams. Barrel arched floors with

To be

New York

ash and concrete fire protection.

altered

Retrofit sprinklers.

680 Folsom Rigid frame Composite deck floors with Office 14 Under San Francisco

cement spray protection to

construction

columns and beams. Underside of

floor decking not protected.

Sprinklers throughout

Empire State Framed Concrete encased columns and Office 102 1931 Building shear truss beams. Reinforced concrete

New York

floors (poured).

No sprinkler protection

AON Center Framed tube Composite deck floors with Office 62 1973 Los Angeles


columns, beams and underside of

floor decking.

Retrofit sprinklers. BMO Framed tube Composite deck floors with Office 72 1975

Toronto




Sprinklers throughout.

Brookfield Framed tube Composite deck floors with Office 49 1992 Place


Toronto



Sprinklers throughout Constellation Framed tube Composite deck floors with Office 35 2003

Place

cement spray protection to Los Angeles




1 Maritime Braced tube External steel frame concrete Office 27 1967 Plaza

encased. Internal columns, beams

San Francisco

and underside of composite floor

decking cement sprayed.

Retrofit sprinklers. John Hancock Braced tube External steel frame concrete Office 100 1970

Building

encased. Internal columns, beams

Chicago

and underside of floors cement sprayed.

Retrofit sprinklers.

Willis Tower Bundled tube Composite deck floors with Office 108 1973 Chicago


columns, beams and underside of

floor decking.




4 DESIGN OF REINFORCED CONCRETE FRAMED BUILDINGS

This section reports and discusses reinforced concrete framed buildings. Two case studies of

buildings visited are discussed to illustrate building construction and fire protection methods used

for these types of buildings in North America.

4.1 Background to reinforced concrete framed buildings

Reinforced concrete is an excellent building material. Concrete possesses high compressive strength

whilst steel has high tensile strength. An important advantage with reinforced concrete construction

is its excellent fire resisting properties, providing sufficient concrete cover is used to protect the

steel reinforcement. Tall buildings are designed to withstand massive building loads and resist

extreme imposed loads such as wind. Because of this the structural elements tend to be large which

enhances the buildings fire resisting properties. Additionally most of the buildings visited were of

residential occupancy with small cellular units, thus restricting the potential for fire spread.

There are many structural systems used for reinforced concrete buildings, including a basic rigid

frame for buildings up to 20 storeys. Shear walls and framed tubes are utilised to further strengthen

building structures allowing taller building heights. At the other extreme end of structural design are

‘Tube-in-tube’, and ‘Modular tube’ forms of construction which are used to build the super tall High

Rise buildings. Some buildings use a combination of these forms of structural design. All reinforced

concrete buildings visited were provided with sprinkler protection throughout.

The following is a review of 2 buildings visited, typical of this form of construction;

Trump International Tower in Chicago, and

Devon Energy building in Oklahoma City.

4.2 Trump International Tower Chicago, completed in 2009

This building is built alongside the Chicago River in the downtown area, reference Figure 36. The

lower part of the building up to floor 29 is designed for hotel use, with apartments above. Below

grade there are 4 basements, and interspaced within the building, are car parking, restaurants, and

health spa floors.

Overall the building has 3 distinctive setbacks designed to harmonise with neighbouring buildings.

These are at;

Level 16 which corresponds with the height of the neighbouring Wrigley building

Level 29 relates to the Marina City Towers

Level 51 aligns with the IBM building

The building then towers up to level 96 and the roof, a height of 1170ft (357m). These setbacks

together with external rounded surfaces assists the breaking up of wind patterns thus minimising

imposed building forces on the structure.



Figure 36 Trump International Tower Chicago

The building design centres on a central core with outrigger systems which eliminates the need for

building dampers. The stiffness and weight of the building, combined with setbacks, support and

stabilise the tower resulting in minimum building movement. Reinforced concrete provides for a stiff

frame and enables flat-slab construction making it cost effective. Ground breaking high performance

concrete was used rated up to 16,000 psi and pumped and placed to an elevation of 650ft (198m)

above grade. Residential floor thicknesses are 9in (230mm) spanning up to 30ft (9.1m) without

further perimeter spandrel elements. The central concrete core is composed of six walls at the base

of the building, all heavily reinforced with steel bar, reference Figure 37, which decrease to two walls

at level 51.

Figure 37 Construction of central core wall, heavily reinforce with steel rebar reference,

http://www.cement.org/buildings/buildings_mixed_trump.asp

Massive reinforced concrete out-riggers at each setback level and the roof, tie the concrete core to

perimeter columns, thus increasing the buildings stiffness and resistance to wind effects. Large

diameter reinforced concrete columns of 6ft (1830mm) are used around the perimeter of the

building, and at the lower levels of the internal parts of the building, reference Figures 38 and 39



respectively. By using fewer and larger diameter columns at the perimeter views over the Chicago

River area are improved.

Figure 38 Large Perimeter columns Figure 39 Large internal columns

The foundations of the building are piled to a depth of 110ft (36m) through stiff clay and limestone

bedrock. Each pile has a steel sheath filled with concrete, and the piles are tied together with a 10ft

(3m) thick reinforced concrete slab. This slab is heavily reinforced with steel rebar, reference Figure

40.

Figure 40 Foundation slab preparation prior to concrete pouring, heavily reinforced with steel rebar,

reference http://www.structuremag.org/article.aspx?articleID=935

4.3 Summary Trump International Tower

The fire safety provisions, in this substantially constructed building, comprise reinforced concrete

frame, compartment floors throughout with a high degree of compartment subdivision, and

protected shaft enclosures for lifts and staircases, are all in excess of Chicago’s building code.

Likewise fire resistance ratings for all the elements of structure adequately meet building code

requirements.

http://www.structuremag.org/article.aspx?articleID=935



Additionally, water supplies are drawn from Lake Michigan and distributed throughout the building

by high pressure positive displacement pumps giving a system pressure of 350psi (24bar). Fire water

requirements are pumped to large holding tanks staged at various levels in the building which

service the automatic sprinkler system and wet main risers, reference Figure 41 and 42.

Figure 41 Inspection of fire pump systems Figure 42 Fire water holding tank

by the author

The high design specification for this building is partly achieved by the type of construction used and

partly by the policy requirements of the Trump Hotels organisation. It can be concluded that this

building is well and truly protected in the case of a fire incident.

Interestingly, other systems such as lightning protection rods are also an essential part of the overall

safety package. Figure 43 shows the Trump and Willis Towers being struck simultaneously on the

evening of 23 June 2010.

Figure 43 Lightning striking the Trump and Willis Tower reference,

http://www.dailymail.co.uk/news/worldnews/article-1289162/Lightning-strike-Willis

http://www.dailymail.co.uk/news/worldnews/article-1289162/Lightning-strike-Willis



4.4 Devon Energy building Oklahoma City, completed in 2012

This building complex is built in the down town area of Oklahoma City, reference Figure 44. The

occupancy use of the building is that of offices with a single occupier which is the head-quarters of

Devon Energy Corporation. The company employs approximately 3,000 staff at the site. The complex

comprises a 51 storey tower block with a 6 storey entrance atrium, below grade a basement, and

restaurants on floors 48 and 49. The tower block is adjoined by other buildings including a 10 storey

car park, a further 6 storey office building, single storey fitness centre and a 285 seat auditorium.

Figure 44 Devon Tower Oklahoma

The tower building at a height of 844ft (256m) is the tallest building in the State of Oklahoma. The

cross sectional area of the tower is a modified reuleaux triangle, with each curved side formed by 2

flat surfaces. Inlets are also designed into the points on the triangle, and the top section contains

additional tapering flat surfaces. The cross sectional area tapers from large foot print areas at grade

level and gradually reduces with building height, reference Figures 45 and 46.

Figure 45 Sectional inlets with Figure 46 Floor plan of modified

tapering flat surfaces at the top reuleaux triangle



The shape of the building has been carefully designed in order to break up wind flow patterns, thus

reducing imposed wind forces on the structure of the building. It is important to note Oklahoma

suffers frequent tornados which can generate wind speeds up to 300 mph (482 km/h).

The building design centres on a tube-in-tube design with a strong central core connected through

floors to the equally strong external parts of the structure. The stiffness and weight of the building

combined with the carefully designed exterior, support and stabilise the tower resulting in minimum

building movement.

Large diameter reinforced concrete columns are used around the perimeter of the building, and at

the lower levels of the internal parts, reference Figures 47 and 48 respectively.

Figure 47 Large diameter external columns Figure 48 Large diameter internal columns

In addition the substantial construction of the building is illustrated with large reinforce concrete

beams, reference Figure 49 and thick wall construction, reference Figure 50.

Figure 49 Large reinforced concrete beams Figure 50 Thick reinforced concrete walls



The foundations of the building are piled and tied together with a 10ft (3m) thick reinforced

concrete slab. This slab is heavily reinforced with steel rebar, reference Figure 51.

Figure 51 Foundation slab preparation prior to concrete pouring, heavily reinforced with steel rebar

The Devon Energy Tower has a comprehensive control room which is capable of dealing with a fire

incident on its head-quarters site and any other incident at its numerous gas and oil installations

around North and South America, reference Figure 52.

Figure 52 Control room at the Devon Energy Tower

4.5 Summary Devon Energy Tower

It can be concluded this building adequately meets the fire protection requirements (similar to the

Trump Tower building previously reported) because of the following provisions;

Compartment floors throughout with protected shaft enclosures for all lifts and stairways

High levels of fire resisting construction prevail for structural elements

Good fire water supplies with adequate buffer capacity within the building

Sprinkler installations are provided throughout the building

Note: From observations it was noticeable that extremely limited use is made of pre-cast concrete in

the construction of High Rise buildings in the USA.



5 EARTHQUAKE PROTECTION DESIGN

Making buildings heavier and stronger means they are less likely to fail in an earthquake, however

this is very expensive. Sometimes a very heavy pendulum called a “Tuned mass damper” is installed

high up in High Rise buildings. An earthquake event swings the damper which absorbs the

earthquake forces away from the buildings structure. The mass of these dampers can be as high as

600 tons.

From my visit to San Francisco I came across two buildings designed with earthquake systems;

One Maritime Plaza and,

680 Folsom Street

5.1 One Maritime Plaza San Francisco

On the 17 October 1989 a major earthquake struck the San Francisco Bay area. Caused by a slip

along the San Andreas Fault, the quake lasted 15 seconds, and measured 6.9 on the Richter scale. It

killed 63 people, injured 3,700 and made up to 12,000 people homeless.

I was fortunate to meet Joe McBride the chief engineer of this building who was at work on the 17th

floor at the time of the earthquake. It was good to hear first-hand experience of such a dramatic

event. His vivid recollection was of the to and fro response of the building, and most importantly,

the twisting effect throwing office chairs and people around the floor area. This eye witness account

will last in my memory. The building withstood the earthquake with only minor damage. Since this

event, the building owners initiated a seismic study and implemented a project to further strengthen

the building against future earthquakes. The project work was carried out by a specialist seismic

engineering company, Rivera Consulting Group Inc.

The project included the following alterations to the building and its structure;

Installation of steel diagonal braces around the base of the tower at the Plaza level,

reference Figures 53 and 54. These “W” frames strengthen the structure particularly from

twisting action.

Figure 53 Ground level diagonal bracing Figure 54 “W” frames in perspective

frames.



Installation of new horizontal beams at floors 8, 14 and 20 of the external frame. These

beams strengthen the corners of the building, spanning between the corner and first

column. A total of 6 additional beams were fitted to the elevation, reference Figures 55 and

56.

Figure 55 Additional 6 horizontal beams Figure 56 Close up view of one additional

to this elevation beam

Structural strengthening was also carried out on the “X” braces at the building core, and at

selected connection points.

Reinforcement works for stubs connecting floor framing to exterior braces at selected

points.

On plant room floors, additional anti-vibration dampers were installed to machine plinths to

complement existing springs, reference Figure 57.

Figure 57 Plant room plinths fitted with additional dampers (green boxes), to act together with

existing springs.



5.2 680 Folsom Street San Francisco

This 1960’s building, previously discussed in section 3.3 of this report, is currently under construction

alterations and when completed will have 2 additional floors making it a 14 storey building. Floor

areas have also been greatly increased. Within the design of the new building seismic protection has

been included which will meet current San Francisco building code requirements.

A new central concrete elevator core will pivot on top of a single friction pendulum bearing at the

basement level, reference Figures 58 and 59. This new stiff core allows all floors of the steel frame to

lean uniformly and spread any earthquake movement evenly throughout the entire steel frame. This

prevents the possibility of a storey collapse. Earthquake action will also spread the strength of the

existing frame uniformly over the height of the building. Another desirable feature includes the

frame acting as a spring that returns the building to plumb after an earthquake.

Figure 58 Friction pendulum bearing fitted to the Figure 59 Elevator core pivoted on friction

base of the elevator core reference, pendulum bearings reference,

Tipping Mar – Project: 680 Folsom Street Tipping Mar – Project: 680 Folsom Street

Earthquake protection measures which are designed into High Rise buildings not only safeguard the

occupants of the building during extreme events but also assist fire fighters during any subsequent

fire or rescue operations. Further protection is also afforded in terms of reducing property damage

and assisting business continuity after an event.



6 OTHER BUILDING DESIGN FEATURES

Throughout my visits I came across a range of building design features which will have an implication

on the safety of buildings during fire, rescue or extreme events such as earthquake or blast effects.

My findings include the following designs;

Wall construction (non-loadbearing)

Large floor areas

Glazing systems

Emergency lighting systems

Atrium design

Helicopter landing decks

6.1 Wall construction (non-loadbearing)

Once the main structures of a storey are completed and prior to the start of any building services

work, steel studs are fixed to the underside of the floor. These are then aligned with final wall

positions, reference Figures 60 and 61. The alignment of building services follows the guidance of

fixed steel stud channels. Steel frame studs were used throughout for all new construction work.

Figure 60 Steel stud channels fixed to the Figure 61 Steel stud wall complete with

underside of floor to pre-determined wall boards

wall alignments

Further, non-loadbearing wall structures requiring fire resistance levels up to 3hrs comprised the

following component parts, reference Table 11;



Table 11 Construction components related to fire resistance rating levels for non-loadbearing walls.

Fire Inner facing Steel stud channel Outer facing

Resistance

Rating

1hr 5/8in gypsum panel 3 5/8in 25 gauge 5/8in gypsum panel

2hrs 2x 5/8in gypsum panel 3 5/8in 25 gauge 2x5/8in gypsum panel

3hrs 2x 5/8in gypsum panel 3 5/8in 20 gauge 3x5/8in gypsum panel

Note: further heat and acoustic insulation materials are fitted within steel stud channel sections.

6.2 Large floor areas

Many High Rise buildings in North America have large floor areas, much bigger than in the UK. From

my observations I found several examples. The largest floor areas found were in the Bank of

Montreal Offices building in Toronto, a tower building of 72 floors, reference Figure 62. The

dimensions of the floor are 190ft (57.9m) by 180ft (54.9m) with a central core location for the lifts

and staircases. Some of these floors are used as open plan offices. This is significant because it is

known fire could spread throughout the floor, known as travelling fires, resulting in a serious fire

attack on the structure. Further, under these conditions the fire could also spread out of the external

windows and affect the storey above, in what is known as conflagration. Although we know about

the resulting behaviour of such fires we do not fully understand them. This is intended to be the next

stage of future fire research.

Figure 62 Large floor areas in the Bank of Montreal Offices Toronto

Another general observation from my visits was the ease in which designers are allowed to open up

floors within High Rise buildings without any additional fire protection. A good example illustrating

this point is the 75 storey building at 157 West 57th Street New York. This building, under

construction, is designed to be a hotel up to the 22nd floor with apartments above. Some floors

contain duplex apartments spanning two floors such as the 71st and 72nd floors, reference Figure 63.



It can be seen that a large open space spans the two floors. Presumably the safety justification is

achieved with the 3hrs fire resistance rating for the elements of structure (greater than the UK)

complemented with sprinkler protection throughout the building. This is all in accordance with the

New York City building code. Stunning views are to be had out of the duplex apartment, overlook

Central Park, reference Figure 64. Price of the apartment a cool $98,000,000!

Figure 63 Open floors in the duplex apartment Figure 64 Views overlooking Central Park

6.3 Glazing systems

Three types of glazing systems were observed including, external, fire resistant and impact resistant.

6.3.1 External glazing

External curtain wall glazing comprised, factory made glazed panels mostly of a storey height in

length, fixing brackets and seals, reference Figure 65. Top sides of glazed panels are fixed via

brackets to the floor slab, reference Figure 66. The bottom side of the next glazing panel above rests

within the channel section of the lower panel complete with a seal. Glazing panels are designed with

multiple layers of glass providing heat and sound insulation. They are not fire resistant.

Figure 65 Curtain wall glazing Figure 66 Floor slab bracket fixed to the slab

glazing panel.



Planar glazing systems were observed in several buildings used as external glazing and perimeter

glazing for atria, reference Figures 67 and 68. Some of these systems were fixed to space frames.

Figure 67 External planar glazing system Figure 68 Atria perimeter planar

glazing system

Lessons were learnt following the fire at the AON building in Los Angeles, in which the fire

department had difficulties in safely breaking external glass to ventilate the fire during the incident.

Every fifth glazing panel throughout the building was replaced with panels of tempered glass which

breaks into small fragments compared with the original float glass breaking into dangerous large

shards.

6.3.2 Fire resistant glazing

Fire resisting glazing appears not to play any significant role in North America. It is only used in

limited applications and architects generally do not appear to select this design feature to any great

extent. Cost parameters are the major set-back. However, from discussions with fire engineering

consultancies, the trend appears to be changing with more fire resistant glazing being specified on

future building developments.

Wired glass is used internally in buildings for separating high hazard areas from accommodation

spaces. It is also used on external walls for separation of internal high hazard areas from public

access externally. Wired glass is probably selected because all fire resisting walls are required to pass

the fire resistance test and an additional hose stream test, see section 2.3.3 of this report.

Additionally, because High Rise buildings are fitted with sprinklers throughout, there is a tendency to

extend the system and protect glazing with sprinkler heads fitted to both sides of the glass,

reference Figure 69. Sprinkler heads for this application have special deflector plates fitted to

achieve the required water distribution over the glazing. This application of sprinklers is not specified

in the IBC codes but it has become acceptable practice.



Figure 69 Sprinkler heads fitted on both sides of glass

During my visit I was able to witness one application of fire resisting glazing at the Russ building in

San Francisco. The glass was fitted to a protected shaft wall providing stairway access to an office

floor, reference Figure 70. The required fire resistance rating for the shaft walls was 2hrs. The

laminated glass markings revealed the following information;

Classified UL: 9FX5 – Pilkington Pyrostop: 120–104, cat II: W-OH-T-120:

120 minutes-54mm: North America

Figure 70 Fire resistant glazing rated at 120 minutes

Because wired glass does not provide 2hrs fire resistance the preferred selection was laminated fire

resisting glass. This design feature obviously maintains desirable day light for the office.

6.3.3 Impact resistant glazing

At the AON building in Los Angeles the control room on the ground floor adjoins a goods delivery

bay. This dock area was used many years ago for off-loading money to the then ‘First Interstate

Bank’. To maintain high security systems the glazed screens in the control room are designed to

resist bullet impact, reference Figure 71.



Figure 71 Control room with high impact bullet resistant glazing

6.4 Emergency lighting systems

From my observations, most buildings in North America appeared to use somewhat dated signage

for the emergency lighting systems. Signs were displayed with instructions in words and illuminated

in red, compared with UK pictograms and green illuminations. However the latest codes in New York

and Chicago do appear to be following UK and European designs.

6.5 Atrium design

A large internal space in a building which breaches structural floors is called an atrium. This form of

building design is popular with architects and building occupants alike. It allows designers to use

building spaces more adventurously by improving internal communication and utilising more natural

light, reference Figures 72 and 73.

Figure 72 16 storey atrium Figure 73 6 storey office atrium

R Thompson Center Chicago Devon Energy building Oklahoma

Administration centre for the State if Illinois

Atrium designs are permitted in North America so long as IBC code requirements are met. The

building must be in compliance with the High Rise section of the code, and must have a smoke



control system designed to technical guidance in “BOCA 1990”. The need for this is in lieu of full

compartmentation of the building because accommodation floors are open to the atrium. The bulk

of design requirements are in the supplementary guidance document with little mention in the

building codes.

However, a few details are specified in the IBC code including; smoke control minimum exhaust

volumes of 6 air changes per hour for atrium volumes of less than 660,000ft3, and 4 air changes per

hour when the volume of the atrium is greater than 600,000ft3. The absolute minimum exhaust flow

rate allowable is 40,000 ft3 per minute. Figure 74 shows the mechanical exhaust fans used for the

Devon Energy atrium, and Figure 75 shows the exhaust grilles on the top level of the atrium,

aesthetically designed and located. In addition to this, the code specifies the following information

to be submitted on plans for city approval, including;

Total area and volume of the atrium

Opening sizes with volume flow rates, complete with direction of flow (exhaust/supply)

Supply openings to be sized for 50% of exhaust capacity

Exhaust to be at the top of the atrium with intake at the bottom

Smoke detectors to be located at the top of the atrium and around the perimeter

Activation of the smoke control system to be from either of the following; a sprinkler

system, or smoke detectors in the atrium, or by manual switch at the fire alarm panel

Figure 74 Mechanical smoke exhaust fans Figure 75 Smoke exhaust grilles on the top

Devon Energy building Oklahoma City storey of the atrium.

Devon Energy building Oklahoma City

When construction of a large atrium is completed and before occupation takes place, it is common

practice to test the performance of the smoke extraction system. To simulate smoke from a fire,

special candles are used. Both the fire and building departments would be in attendance during this

test.

6.6 Helicopter landing decks

In Los Angeles the building code requires a helicopter landing deck to be installed on the roof of new

buildings greater than 150ft (45.7m) in height. The AON building in Los Angeles has such a helideck

installed on the roof, reference Figure 76.



Figure 76 Helicopter landing deck

AON building in Los Angeles

This facility is for use by the fire department for fire emergency purposes. The fire department has a

fleet of 5 helicopters available 24/7 with capabilities of night time flying. None of the other cities

visited in North America has this requirement. The cost of building a helideck is approximately

$0.5m. Views from the top of this building clearly shows helidecks fitted to five neighbouring High

Rise buildings, reference Figure 77.

Figure 77 Los Angeles High Rise buildings with helicopter landing decks

An interesting safety point arises related to occupant escape procedures with the use of helicopters

at fire emergencies. The general escape concept is to always travel downwards and out of a burning

building. Safety plans for High Rise buildings with helidecks in Los Angeles will need to specify

occupant evacuation procedures and identify when escape should be upwards towards the roof

area. I would assume upward escape is only viable under the supervision of the fire department.



7 MISCELLANEOUS BUILDINGS

From my visits I was able to photograph the following buildings externally. These are some of the

first High Rise buildings constructed in the USA some 100 years ago. They all have historical interest

to the enthusiast, and will prove useful for future development of High Rise training courses.

Fuller Flatiron building, New York

Monadnock building, Chicago

Phelan building, San Francisco

De Young building, San Francisco

The Palace building, San Francisco

Hobart building, San Francisco

Flatiron building, San Francisco

Matson building, San Francisco



8 OKLAHOMA STATE UNIVERSITY

Whilst visiting Oklahoma, I was able to spend a day at the Oklahoma State University. The morning

was spent with IFSTA “International Fire Service Training Association” and FPP “Fire Protection

Publications”. The second part of the day was spent with the technology school of the university.

I met with the director of IFSTA, Dr Craig Hannan, and had useful discussions concerning the

structure of NFPA standards and how they are linked to FPP publications. Interestingly, the

organisation has been in existence since 1933 co-ordinating safe fire fighting practices for the fire

services, and publishing the outcomes in the form of manuals. Fire departments from all areas of

North America are invited to participate in this activity. I was particularly interested in the last

publication of “Building Construction Related to the Fire Service” and the very new publication for

“High Rise Fire Fighting”. Additionally, I met with Dr Mike Wieder, an associate director, and had

discussions related to Federal standards of qualifications, including those at associate, bachelors and

masters levels. To complete my meetings with IFSTA I met with Professor Tony Brown who deals

with disaster management and co-ordinates the annual conference for IFSTA.

The afternoon was spent with Dr Michael Larranaga, the course director for the bachelor’s degree

programme ‘Fire Protection and Safety Technology’. Besides discussing the building construction

parts of the programme I was given a guided tour of the laboratory facilities. These included the

laboratories for;

Fire detection and alarms, designed for hands on fault finding of electrical circuits

Fire burn unit capable of burning fires up to 1MW

Water pumping facilities, complete with set up valves and monitoring equipment

20 water main control valves complete with mains supply to range pipes and sprinkler

heads, including facilities for students to strip down and re-build valves

The largest cabinet display of sprinkler heads I have ever seen. These included heads from

the 1800’s through to latest versions, complete with performance data sheets.

This visit was extremely worthwhile and one which fuelled many ideas for the future.



9 FINAL CONCLUSIONS

1 Building controls

A comparative review of High Rise building controls is reported in section 2 resulting in the

following significant findings;

a) Higher levels of fire resisting construction prevail in the USA compared to the UK, reference

section 2.3.6. These include elements of structure and fire doors. Canada has similar ratings

to the UK, reference section 2.4.

b) The quality of wall construction in North America is of a higher standard than the UK. An

additional hose stream test needs to be satisfied as well as a fire resistance test, reference

section 2.3.4. This is particularly relevant to walls fitted with glazed screens.

c) Compartment designs are treated differently in North America. It is possible to breach

structural fire floors without additional fire protection, reference section 6.2.

d) In North America building controls for void spaces such as suspended ceilings and raised

floor sections is not as stringent as the UK, reference section 2.3.4. Little use is made of

cavity barriers. However, fire stopping is specified which is in line with UK practice.

e) Sprinkler protection is widely adopted in North America and in some cities, retrospective

regulation is in place to up grade older buildings, reference sections 2.3.6 and 2.7. UK hotel

buildings do not require sprinkler protection were as they do in North America.

f) Fire departments in some cities in the USA have enforcement powers for fire safety matters

during construction of buildings, reference section 2.5.1.

2 Steel framed buildings

a) The favoured method of protecting structural steelwork in North America is cement

spraying, reference section 3.2. There are several reasons for this;

It is considered easy to programme appropriate work schedules

Costs are economical because of a competative market

There does not appear to be any environmental constraints with using cement sprays

b) The extent of cement spray application was reviewed with two interesting conclusions;

Some buildings had spray protection applied to all columns and beams, without the

underside of the floor sprayed, reference sections 3.3 and 3.4.

Other buildings were fully protected with cement spray applied to all column, beams

and underside of floors, reference sections 3.5, 3.6, 3.7 and 3.8.

The probable reasons for more fire protection are;

Higher levels of required fire resisting construction in the USA

Shallower profiles of steel decking

Regulators desire to have more property protection

Custom and practice in the USA at the time of building

Possible building insurance requirements.



c) Cladding fire board protection and use of intumescent paints are not favoured in North

America. They are only used for special application, reference sections 3.2 and 3.4.

d) Older forms of fire protecting steelwork were also reviewed; reference sections 3.9 (Empire

State Building), and 3.10 (Metropolitan Life Tower). These used concrete encased structural

elements and floors of ash concrete respectively.

3 Reinforced concrete buildings

Most reinforced concrete buildings in North America are built for residential use. They are

substantially built making them relatively safe in emergency situations, reference section 4. They are

safe because;

a) Structural fire floors are designed throughout the building with a high degree of sub-division,

thus reducing potential fire spread.

b) Required fire resistance ratings for the structure are easily met.

c) All new buildings are sprinkler protected. Retrospective sprinkler installations have been

fitted to some older buildings.

d) Fire water supplies to sprinkler installations and wet main risers are plentiful with adequate

buffer tank capacities.

It was interesting to observe the limited use of pre-cast concrete in High Rise buildings.

4 Wind and earthquake protection

a) Wind loadings are a design requirement relevant to all High Rise buildings, reference section

3.1.4. In many cases it influences the construction style of buildings particularly with taller

ones. This design aspect is important to fire officers as a consideration for fire safety of

occupants. However, it also becomes critically relevant to incident commanders when

dealing with fire emergencies involving possible localised building collapse.

b) Earthquake protection is only relevant to buildings in areas which suffer these events. The

UK does not have such problems. However some fire officers in the UK work in specially

trained teams which undertake urban search and rescue work. These teams are frequently

sent overseas when major disasters occur. Some understanding of the principles of

earthquake design is valuable knowledge to these officers, reference section 5.

5 Fire resisting glazing

a) Fire resisting glass does not play a significant role in North America because of cost.

However, fire engineering consultancies reported a changing trend towards the use of these

systems on new building developments.

b) For limited applications wired glass is used because it satisfies both the fire resistance test as

well as a required hose stream test. The later test is not used in the UK.

c) There is a tendency to protect glazing with special sprinkler heads mounted on both sides of

the glass.

These conclusions are referenced to section 6.3.2



6 General

By undertaking this project, my personal understanding of High Rise buildings has improved

immensely. I have been able to see and photograph over twenty relevant buildings which can be

developed into useful case studies for future fire safety training.



10 NEXT STEPS FOR THE PROJECT

To date, the following presentations including an introduction to the ‘Winston Churchill Memorial

Trust’ have been made;

Date Presentation details Location

3 August 2012 Merseyside Fire and Rescue Srevice Merseyside Training School

Presentation (In-house training) for Liverpool

High Rise building in the UK

17 August 2012 GMC – Institution of Fire Engineers GMC Training School

High Rise Seminar Manchester

Oct and Sept 2012 - Project visit to North America

9 November 2012 London Tall Buildings Fire Safety Meeting The Shard

Presentation of interim project findings London

3 December 2012 North West Regional Meeting GMC Headquarters

Institution of Fire Engineers Manchester

Presentation of interim project findings

Following the submission of this Fellowship Report, the next steps for the project is to present the

findings to my two supporting organisations;

Fire Service College, the central fire officer training establishment in the UK

PFPF Passive Fire Protection Federation, industry sector

Additionally, three regional groups of the Institution of Fire Engineers have expressed an interest for

a project presentation including;

North West area to be held in Manchester

Mid Western area to be held in Bristol

Northern Ireland area to be held in Belfast

Alongside the above activities, the Merseyside Fire and Rescue Service have requested an in-house

professional development presentation based on my North American findings.

I also hope to write a journal article to be published in a construction/fire engineering arena.



Appendix A - References

ASTM, E84, Standard test methods for Surface Burning Characteristics of Burning Materials, , ASTM

International, 100 Bar Harbor Drive, PO Box C700, West Conshohocken, Pennsylvania, 19428-2959,

USA

ASTM, E119, Standard test methods for fire test of building construction and material, ASTM

International, 100 Bar Harbor Drive, PO Box C700, West Conshohocken, Pennsylvania, 19428-2959,

USA

ASTM, E2226, Standard practice for application of hose stream, ASTM International, 100 Bar Harbor

Drive, PO Box C700, West Conshohocken, Pennsylvania, 19428-2959, USA

BOCA 1990, National Building Code, 11 Edition, Building Officials and Code Administrators

International, 4051 West Flossmoor Road, Country Club, IL 60478, USA

BS 476, part 4, 1970, Fire test on materials and structures. Non-combustibility test for materials.

BS 476, part 6, 1989, Fire test on materials and structures. Method of test for fire propagation for

products.

BS 476, part 7, 1997, Fire test on materials and structures. Method of test to determine the

classification of the surface spread of flame of products.

BS 476, part 11, 1982, Fire test on materials and structures. Method for assessing the heat emission

from building materials.

BS 476, part 20, 1987, Method for determination of the fire resistance of elements of construction

(general principles).

BS 476, part 21, 1987, Method for determination of the fire resistance of loadbearing elements of

construction.

BS 476, part 22, 1987, Method for determination of the fire resistance of non-loadbearing elements

of construction.

BS 476, part 23, 1987, Method for determination of the contribution of components to the fire

resistance of a structure.

BS 476, part 24, 1987, Method for determination of the fire resistance of ventilation ducts.

Building Regulations (2000) “Approved Document B, Fire Safety, Volume 2 – Buildings other than

dwellinghouses, (2007 edition)”, Department for Communities and Local Government, RIBA, London,

2007.



Appendix A – References (continued)

IBC, International Building Code (2009), 4051 West Flossmoor Road, Country Club, IL 60478, USA

Mendis P, Ngo T, Haritos N, Hira A, (2007) “Wind loadings on tall buildings”, EJSE international

journal special issue: Loading on structures, pages 41-54

Mir M Ali, Kyoung Sun Moon, (2007), “Structural development in tall buildings: Current trends and

future prospects”, Architectural science review, Volume 50.3, pp205-223



Appendix B - List of Buildings Visited

Location and Address Height and Construction Use and History

1 New York - 157 West 57 Street 1004ft (306m) Hotel + Apartments

75 floors + 2 Basements Under construction

Reinforced concrete

Fully sprinklered

2 New York - Mony Building 375ft (114m) Office

1740 Broadway 26 floors Completed 1950

Steel frame

Fully sprinklered

3 New York - Metropolitan Life Tower 700ft (213m) Future Hotel

5 Madison Avenue 45 floors Under construction

Steel frame

Fully sprinklered

4 New York - Empire State Building 1,250ft (381m) Office

350 Fifth Avenue 102 floors Completed 1931

Steel frame

5 Chicago - 515 North Clark Street 240ft (73m) Hotel

18 Floors Under construction

Reinforced concrete

Fully sprinklered

6 Chicago - 516 North Lake Shore Drive 465ft (142m) Apartments


Reinforced concrete

Fully Sprinklered

7 Chicago - Trump Tower 1,170ft (357m) Hotel/Apartments

401 North Wabash Avenue 96 floors Completed 2009

Reinforced concrete

Fully sprinklered

8 Chicago - Field House Wabash Ave 3 floors Assembly

Roosevelt University Steel frame Under construction

Sprinklered



Appendix B - List of Buildings Visited (Continued)


9 Chicago - Willis Tower 1,450ft (442m) Office

233 South Wacker Drive 108 floors Completed 1973

Steel frame (bundled tube)

Fully sprinklered

10 Chicago - John Hancock Tower 1,054ft (321m) Mixed use

875 North Michigan Avenue 100 floors Completed 1970

Steel frame

Retrofit sprinklers to

commercial floors

11 Chicago - James R Thompson Center 308ft (94m) Mixed use

100 West Randolph Street 17 floors Completed 1985

Steel frame

Fully Sprinklered

12 Oklahoma - Devon Energy Building 844ft (257m) Office

280 West Sheridan Avenue 52 floors Completed 2012

Reinforced concrete

Fully sprinklered

13 Los Angeles - Constellation Place 491ft (150m) Office

10250 Constellation Boulevard 35 floors Completed 2003

Steel frame

Fully sprinklered

14 Los Angeles - AON Center 858ft (262m) Office

707 Wilsher Boulevard 62 floors + 5 basements Completed 1973

Steel frame

Retrofit sprinklers

15 San Francisco – One Maritime Plaza 398ft (121m) Office

27 floors Completed 1967

Steel frame/ seismic retrofit

Sprinklers retrofitted

16 San Francisco – 680 Folsom Street 210ft (64m) Office


Steel frame

Fully sprinklered



Appendix B - List of Buildings Visited (Continued)


17 San Francisco – Russ Building 435ft (133m) Office

235 Montgomery Street 31 floors Completed 1927

Steel frame

Fully sprinklered

18 Toronto – Palace Pier 453ft (138m) Apartments

2045 Lake Shore Boulevard West 46 floors + 4 basements Completed 1978

Reinforced concrete

Sprinklered

191 Toronto – Crescent Place 250ft (76m) Apartments

Crescent Town Road 25 floors Completed 1971

Reinforced concrete

20 Toronto – Ritz Carlton 688ft (210m) Hotel

181 Wellington Street West 53 floors + 6 basements + Apartments

Reinforced concrete Completed 2011

Fully sprinklered

21 Toronto – Bay Wellington Tower 682ft (208m) Office

181 Bay Street 49 floors + basement Completed 1992

Steel frame

Fully sprinklered

22 Toronto – BMO Building 978ft (298m) Office

100 King Street West 72 floors Completed 1975

Steel frame

Fully sprinklered



Appendix C – WCMT Fellowship Timetable – North America

August 30 Thur To New York NYC

August 31 Fri Research Day 1 NYC

September 1 Sat NYC

September 2 Sun NYC

September 3 Mon NYC

October 1 Mon Research Day 16 OKC

September 4 Tue Research Day 2 NYC

October 2 Tue Research Day 17 OKC

September 5 Wed Research Day 3 NYC

October 3 Wed Research Day 18 OKC

September 6 Thur Research Day 4 NYC

October 4 Thur To Los Angeles LA

September 7 Fri To Toronto TOR

October 5 Fri Research Day 19 LA

September 8 Sat TOR October 6 Sat LA

September 9 Sun TOR October 7 Sun LA

September 10 Mon Research Day 5 TOR October 8 Mon LA

September 11 Tue Research Day 6 TOR

October 9 Tue Research Day 20 LA

September 12 Wed Research Day 7 TOR

October 10 Wed Research Day 21 LA

September 13 Thur Research Day 8 TOR

October 11 Thur Grand Canyon

September 14 Fri Niagara Falls

October 12 Fri Grand Canyon

September 15 Sat Niagara Falls

October 13 Sat Grand Canyon

September 16 Sun Niagara Falls October 14 Sun To San Francisco SF

September 17 Mon To Chicago CHIC October 15 Mon SF

September 18 Tue Research Day 9 CHIC

October 16 Tue Research Day 22 SF

September 19 Wed Research Day 10 CHIC

October 17 Wed Research Day 23 SF

September 20 Thur Research Day 11 CHIC

October 18 Thur Research Day 24 SF

September 21 Fri Research Day 12 CHIC

October 19 Fri Research Day 25 SF

September 22 Sat CHIC

October 20 Sat SF

September 23 Sun CHIC

October 21 Sun SF

September 24 Mon Research Day 13 CHIC October 22 Mon Research Day 26 SF

September 25 Tue Research Day 14 CHIC October 23 Tue SF

September 26 Wed CHIC

October 24 Wed To New York NYC

September 27 Thur CHIC October 25 Thur Research Day 27 NYC

September 28 Fri CHIC October 26 Fri NYC

September 29 Sat Research Day 15 CHIC October 27 Sat Research Day 28 NYC

September 30 Sun To Oklahoma OKC

October 28 Sun NYC

October 29 Mon To Birmingham



Appendix D - Press Reports Gloucestershire Echo



Appendix D - Press Reports Bolton News

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