DESIGNING PERFORMANCE-BASED SPRINKLER SYSTEMS: EAST VS. WEST

BY W.K. CHOW AND FIONA S.C. TSUI

Sprinkler protection in Hong Kong (now a Special Administrative Region of China) is required for almost all types of premises except residential buildings or buildings with a total floor area less than 230 m2. The systems are mandated in the Fire Service Installation (FSI) codes, which differ from some overseas countries such as the United Kingdom and the United States, where the benefit sprinklers provide in relation to protecting life and property is taken as an enhanced measure. Basically, the design and installation of sprinklers follow the Loss Prevention Council (LPC) Rules for Automatic Sprinkler Installations with modification pertinent to Hong Kong.1,2,3 The sprinkler system is a hydraulic system with the appropriate pump and pipe works connected to water sources. Water at sufficient pressure and flow at the sprinkler heads will be discharged to control a fire. A precalculated method is commonly used for the design of sprinkler systems. Full hydraulic calculation is allowed so the system can be based on the minimum design discharge density and the assumed maximum area of operation.

Performance-based design (PBD) in the fire safety4,5 or fire engineering approach (FEA)6,7,8 is commonly applied to new architectural features that make it difficult to comply with local fire codes. To apply PBD or set up engineering performance-based fire codes (EPBFC),9,10 it is necessary to understand the physics behind the sprinkler system’s design requirement, including the role and availability of other design standards for sprinkler applications, sprinkler functions in fire safety design, and the performance considerations in modeling a fire environment.11

SPRINKLER SYSTEM

Among various fire protection measures, sprinkler systems aim at controlling, not extinguishing, the fire, according to National Fire Protection Association (NFPA) 750, Standard on Water Mist Fire Protection Systems, 2000, and NFPA 13, Standard for the Installation of Sprinkler Systems, 2002. The system serves the detection and suppression functions and contains a thermal sensing element (glass bulb or fusible link) that operates at a predetermined temperature (such as 68°C). Water will be discharged just as if a valve were turned.

Taking sprinkler design standard BS 5306-2 (2) as an example, more rigorous design provisions are required, such as a duplicate installation valve for a wet-pipe system only and limiting the maximum number of sprinkler heads to 200 per installation/zone. These provisions are imposed to provide better reliability in a life safety system.

In fact, the effectiveness of a sprinkler system relies on several factors, including the fire size at the time the sprinkler system is activated, the characteristics of the sprinkler system (i.e., pressure, flow, water droplet size, and velocity), the geometry of the protected space, and the extent to which the fuel is shielded from the water medium. There are always areas of disagreement, such as the number of heads that operated for a certain task size with an inadequate water supply. A thorough understanding of the basis and criteria for the system’s design can be achieved only through detailed investigations. In using new designs, such as long-throw sidewall sprinklers, it is necessary to carry out in-depth tests, not just to demonstrate compliance with some parts of LPC Rules.

Fast response sprinklers (with a response time index RTI of 50 m1/2s1/2 or less) with a more sensitive thermal sensing element12 would act on the fire when it is still small in size. This design has been recognized to contribute to protecting life safety also by controlling the fire growth at a very early stage, enhancing life protection. However, evacuation is a concern, and people must leave the building before the water discharges.

REVIEW OF DESIGN REQUIREMENTS

Statutory Requirements

The fire suppression system (e.g., sprinkler) is one of the active fire protection measures under the purview of the Director of Fire Services with responsibility delegated from the Building Ordinance Cap.123, Section 16(1)(b).13 The Building Authority may refuse to approve any plans if the plans are not accompanied by a certificate from the Director of Fire Services certifying that the plan satisfies the FSI codes. (1) As specified in the FSI codes (1), and as noted earlier, sprinkler protection is required for almost all types of premises except residential buildings or buildings with a total floor area of less than 230 m2.

Definition of Sprinklered Risk

There are a variety of building occupancies with differing fire risks. Three types of risk are specified in the rules (2): light hazard, ordinary hazard, and high hazard. These hazard risk groupings are based on past fire experiences and research. For example, hospitals are classified as light-hazard occupancies because of the low-hazard contents and the 24-hour attendance, whereas petrochemical works, with their highly volatile and combustible products, are classified as high hazard. However, overseas codes cannot be copied without justification. The classification might vary in different places, depending on the living standard and education of citizens. Those items that work (such as orderly queuing) in the western countries might not be applicable in the Far East. There is also a life safety system in which additional safeguards are considered necessary to ensure reliability even though the hazard is classified in the normal manner.

Design Density Discharges

Each group, risk, and category has a minimum density discharge requirement related to the maximum heat that can be removed by the water. The higher the group or category, the higher the minimum discharge density. The minimum design density discharge and assumed maximum area of operation are as follows: 2.25 mm/min and 84 m2 for light hazard; 5 mm/min for ordinary hazard with Group I 72 m2, Group II 144 m2, Group III 216 m2, and Group III special 360 m2; and 7.5 mm/min to 12.5 mm/min and 260 m2 for high hazard.

Water Supplies

At least two water supply types are acceptable in the British Standard Institute BS S5306-2: town mains with a pressure tank, gravity tank, or elevated private reservoir or town mains with an automatic pump (2).

Water tank capacity must guarantee a 30-minute stored supply with a means for automatically refilling the supply tank.. That is the reason the number of sprinkler heads that ignite has to be carefully considered.14 If the tank is situated at the upper level of the building and a transfer pump is needed to relay water to the tank, the pump shall be able to refill the tank to its full capacity within six hours. The transfer pump shall be powered by an essential power supply.

In addition, the amount of water storage depends on the hazard risk classification. Design capacity for a storage tank of a precalculated installation not dependent on inflow is to be determined according to the height of the highest sprinkler above the lowest sprinkler (15 m, 30 m, and 45 m). A single end fed from a town main supplying a tank holding two-thirds of its capacity can be used if there is a direct telephone link to the fire brigade.

Life Safety System

A life safety system, which shall be used for all projects, shall be of the wet pipe type; the installation valve set shall incorporate dual stop valves or bypass valves and 200 sprinkler heads per installation or 200 heads per zone, and shall have subsidiary stop valves. All stop valves shall be electrically monitored and secured open. Wet pipe systems would have water in the pipes at all times. This is the simplest way to install and maintain. There are a controlling stop valve, a wet alarm valve, a water motor alarm gong, and a flow test facility.

Fire Brigade Access

Alarm valves shall be located at ground level inside an FS control room or valve chamber accessible by the fire brigade. In high-rise buildings, if the static pressure of the system exceeds the working pressure of the alarm valve, the alarm valve could be located at upper floors with the Fire Services Department’s approval.

Sprinkler Pump Installation

A jockey pump is required for the high-rise installation to maintain the static pressure at any alarm valve at not less than 1.25 times the static head difference between the valve and the highest sprinkler. The jockey pump shall not be so large as to prevent the operation of sprinkler pumps (duty and standby) when a single sprinkler operates.

Each pump shall have an independent starting arrangement individually connected to the delivery pipe between the appropriate pump delivery check valve and the isolating stop valve. Provisions for fixing a direct reading flowmeter shall be allowed at the pump delivery branch downstream of each outlet check valve for testing.

Alarm and Indication Signals

Alarm and indication signals required for life safety premises shall include alarms for pumps not working properly, supply indicator lamps, an automatic power failure alarm, and zoned installation monitoring (multistory buildings). All the monitoring signals for subsidiary valves and main gate valves shall be fed to a proprietary-made AFA panel approved by the Fire Services Department.

Sprinkler Spacing

The spacing and location of sprinklers correspond to the hazard occupancy. The maximum coverage area per sprinkler (ceiling type) is 21 m2 for light hazard, 12 m2 for ordinary hazard, and 9 m2 for high hazard. The maximum distance between sprinklers is 4.6 m for light hazard, 4 m for ordinary hazard, and 3.7 m for high hazard. Sprinklers must not be located more than half the design space from the wall or partition. The spacing and location of sidewall sprinklers for these hazards are also specified.

The minimum distance between any sprinklers in ceiling protection is 2 m, to prevent the first operating sprinkler from wetting/cooling the adjacent sprinklers and delaying operating time. This minimum distance does not apply if any intervening structure obscures the water spray from the adjacent sprinklers. When designing the sprinkler layout, several rules and requirements are to be considered in addition to the perimeter walls, such as the distance from the beam, ceiling soffit, and extra head underneath a larger air duct.

The sprinkler head shall be as close to the ceiling as practical to enable the hot gases to effectively operate the sprinkler head. The minimum distance between the roof/ceiling soffit and the sprinkler deflector is 300 mm for combustible ceiling, 450 mm for noncombustible ceiling, and 150 mm for open-joisted ceiling. A clear space of 500 mm shall be maintained below the sprinkler to allow the sprinkler spray pattern to fully develop. For high-piled storage, other spacing arrangements apply to sprinklers installed within racking.

Pipe Sizing

There are standard precalculated pipe tables and a fully hydraulically calculated method for sizing the pipe work. The precalculated tables allow the designer to size the sprinkler piping up to the “Design Point.” From the “Design Point” to the system “C” gauge, the pipes must be sized by hydraulic calculation. The “Design Point” or points will vary with the hazard classification and the piping layout.

The fully hydraulically calculated pipe-sizing method can be used for ordinary and high-hazard systems and can provide some cost savings by reducing the pipe diameters normally used in precalculated systems. This is true for certain types of buildings and piping layouts.

Materials and Fittings

There are minimum requirements for materials to be used in the manufacture of a sprinkler system. These materials are pipes, fittings, valves, sprinklers, and meters referred to in the British Standard or as an “Approved Item.”

System Maintenance and Periodic Inspection and Testing

Maintaining the system in the future should be considered at the design stage to avoid abnormal maintenance costs that could result from poor access, abnormal drainage downtime, and drainage facilities. A registered fire service contractor must conduct the annual inspection and testing of the system. System shutdown time should be kept to a minimum. The Fire Services Department must be notified if the system will be shut down for more than 24 hours.

OTHER DESIGN STANDARDS

Before Hong Kong was reunited with China, U.K. design rules were followed. An example is the BS 5588 prescriptive code.15 The Authority accepts other internationally recognized design standards on a case-by-case basis, such as those from the United States.

There are currently three recognized standards in the United Kingdom for the installation of sprinkler systems:

  • BS 5306: Fire extinguishing installations and equipment on premises, Part 2: (1990) Specification for sprinkler systems.
  • BS EN 12845 (2004): Fixed fire fighting systems-Automatic sprinkler systems-Design, installation and maintenance.
  • BS 9251 (2005): Sprinkler systems for residential and domestic occupancies: Code of practice.

The BS 5306 and BS EN 12845 systems are generally used for industrial and commercial buildings. Under the LPC rules, there is additional guidance to supplement the BS 5306 and BS EN 12845 standards to meet the insurers’ requirements.

Examples of U.S. sprinkler design standards include National Fire Protection Association (NFPA) 13, Standard for the Installation of Sprinkler Systems, 2002; NFPA 13R, Standard for the Installation of Sprinkler Systems in Residential Occupancies Up to and Including Four Stories in Height, 2002; and NFPA 13D, Standard for the Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes, 2002, as well as those of FM Global.

ROLE OF SPRINKLER IN PERFORMANCE-BASED DESIGN

PBD or FEA is an increasingly common approach to incorporating unique architectural features to achieve aesthetic, cost, and functional goals while maintaining safety levels for building occupants and fire brigades. Automatic sprinkler systems are widely used in building projects with PBD as well as in prescriptive building design because of the mandatory requirements under the FSI codes (2005). PBD systems will yield the desired performance only if the system is properly designed for the scenario in which it is to operate.

In Hong Kong, sprinklers are not usually regarded as a trade-off or an alternative to other fire safety measures, such as compartmentation. They are viewed as a key active fire protection measure. The reason for this is that safety education and awareness in the Far East are not as good as in countries such as the United Kingdom or the United States. In any event, the functions, limitations, and flexibility in design under PBD should be well understood, and it should be demonstrated that the systems work.

In the context of performance-based fire safety design, sprinklers are recognized for satisfying the following fire safety objectives (BS 7974-4, 2003):16

  • To protect specific areas where the fire must be suppressed before endangering other areas;
  • To protect areas adjoining the space(s) where there is a calculated chance that the fire cannot be contained within the risk areas; and
  • To protect areas designated as requiring protection as an alternative to passive or other measures.

The function or benefits of sprinklers in relation to building fire safety design are viewed differently in our code than in the codes of countries overseas. However, such design standards cannot be applied directly in the Far East without thoroughly understanding the physics behind the design or making a detailed engineering analysis of the specified building and occupant characteristics. Further, public awareness of safety is another issue. This is related to education, training, and citizen responsibility. Some examples of using sprinklers to compensate for the possible risks of not complying with the codes are listed below.

Nonfire-resisting glazing. Use of closely spaced sprinklers located at a distance from the glass wall with less than 305 mm and at 1.83 m interval to protect the tempered glass wall is allowed in NFPA 101, Life Safety Code, 2006, in lieu of fire rated glass for separating fire in an atrium from the rest of space. Sprinklers are designed by following NFPA 13. There are studies17,18 on the use of drenchers or window sprinkler heads for protecting nonfire-resisting glazing as an alternative means of achieving compartmentation in a building. Window sprinklers, specially designed open nozzles with a deluge valve, available on the market would produce a water curtain for protecting windows, walls, and roofs against exposure fires [American Society for Testing Materials (ASTM) E119, Standard Test Methods for Fire Tests of Building Construction and Materials, 2000.] The performance of window sprinklers in protecting nonfire-rated glass depends on the test of the water discharge pattern, flow, and the pressure deliveries specific to the manufacturer.

When considering alternative design solutions based on overseas product design standards, we must take into account that the sprinkler application for the wetting of glass is outside the scope of the local design standard BS 5306-2, 1990, for ceiling-mounted or sidewall sprinklers. The sprinklers should be tested to verify their ability to protect heat-strengthened or tempered glass. Hence, when there is local application, the following factors should be considered: local accepted fire resistance test, type of glass to be used, and design arrangement (e.g., spacing, orientation, pressure, and flow delivery) of the heads. More research is needed; designs in those PBD projects must be demonstrated with full-scale burning tests.19

Means of escape design. In some overseas prescriptive rules, such as NFPA 101, the allowed escape travel distance for a sprinkler-protected building is longer than that for a nonsprinkler-protected building. One example is an assembly occupancy following NFPA 101. The travel distance limit is 45 m for nonsprinkler-protected space and 76 m for sprinkler-protected space. Within the prescriptive design specification, sprinklers in this project were provided to compensate for the possible risk caused by longer travel distances. Other fire safety measures required under the same code shall not be ignored. The control of materials in terms of flame-spread index and smoke-developed index are usually more rigorous within NFPA 101.

When considering a performance-based design for an application in Hong Kong, fast-response sprinklers can be selected; they might help to extend the available safe egress time20 by limiting the amount of smoke produced by a fire and reducing heat exposure. A detailed engineering report that evaluates the predicted performance in prolonging the safe egress time should be submitted instead of just making reference to the overseas prescriptive rule. Steam generation and other potential effects for the occupants not yet evacuated should be monitored. Another concern is occupants with mobility difficulties.

Compartmentation. The aim of fire-rated compartments is to limit fire spread. A fire is expected to grow within the compartment itself. In some overseas codes,21,22 compartment size is allowed to be extended with sprinkler protection. Life safety is to be achieved by providing an effective means of escape or active smoke control as in ABCB (1996) (22). It is understood that the presence of sprinklers is expected to control fire growth23 within a compartment, hence limiting property damage if they operate properly. In a performance-based design in an oversized fire compartment, other life safety concerns, including evacuation and the fire environment specific to the local conditions, should be carefully considered.

DESIGN FIRE SIZES FOR SPRINKLER-PROTECTED SPACE

The design fire size is an important input parameter when undertaking fire engineering analysis. You must understand the likely effect of a sprinkler system on a fire to be able to select the appropriate design fire size. NFPA 13 and NFPA 750 define the terms “control,” “suppression,” and “extinguishment.” Fire control in NFPA 13 means limiting the size of a fire by distributing water so as to decrease the heat rate and pre-wet adjacent combustibles while controlling ceiling gas temperatures to avoid structural damage. Fire suppression in NFPA 13 means sharply reducing the heat release rate of a fire and preventing its regrowth by applying sufficient water directly through the fire plume to the burning fuel surface. Fire extinguishment in NFPA 750 means the complete suppression of a fire until there are no burning combustibles.

The effectiveness of a sprinkler system will generally depend on a number of factors, including the reduction of the degree of heat release rate reduction after sprinkler actuation, the type of sprinkler system (e.g., wet, pre-action), the type and location of sprinkler heads, the geometry of the protected space, and the type of fuel and its orientation. As demonstrated through full-scale burning tests on small fires by Chow24, the design fire size estimated by using t2-fires (NFPA 92B, Guide for Smoke Management Systems in Malls, Atria, and Large Areas, 2002) has to be extended to beyond the activation time. Selecting the design fire size is important, and its interaction with sprinkler operation should be considered carefully. Again, the design might have to be confirmed by full-scale burning tests in some projects.

PERFORMANCE-BASED DESIGN FOR SPRINKLER SYSTEMS

PBD, in addition to using a fully hydraulically calculated method for sizing the storage tank capacity, pump duties, and pipe work, also is relevant for incorporating a nonstandard sprinkler installation into the main sprinkler system for checking the hydraulic performance (i.e., the duration of water discharge under different fire scenarios, pressure, and flow delivery). Examples include the portion of the system’s sprinkler pumps and storage tank that serve both typical ceiling sprinklers and a deluge system of a group of window sprinklers or long-throw sprinklers.

As highlighted by Russell,25 modeling of spray droplet formation and distribution might be required in PBD of automatic sprinkler systems. Computational fluid dynamics (CFD) packages are applied. The sprinkler system design area is assessed to determine the number of sprinklers that operated during a fire event to collect data for measuring how successfully the sprinklers performed. For the type of sprinkler systems (typical ceiling/sidewall sprinklers) for which design standards (Reference 2, for example) are used, a degree of expected performance has been established to ensure quality products, appropriate application of system design and installation criteria, and proper system inspection and maintenance.

However, there are many problems in modeling the performance of a sprinkler system. Therefore, for those situations that involve new sprinkler types (e.g., long-throw sprinkler, water mist/fog) or nonstandard design applications (e.g., coverage outside the area served by typical heads is demanded), full-scale burning tests are necessary.

SPRINKLER SYSTEM FOR A SUPERTALL BUILDING

Hong Kong has tall or “supertall” buildings for residential or commercial uses. Following is an example of how a sprinkler system was designed for a supertall composite building described as follows:

  • An eight-story shopping complex (1/F – 8/F) podium building with two towers above.
  • Tower A is a 35-story hotel tower (9/F – 43/F) with one refuge floor at 22/F.
  • Tower B is a 69-story office (9/F – 33/F) and hotel (34/F – 77/F) tower with two refuge floors at 24/F and 53/F.
  • Several car parks are located in the basement.

Three occupancy types were identified: (1) Ordinary Hazard (OH) group I for hotels, restaurants, and cafes; (2) OH group II for offices; and (3) OH group III for shopping arcade, retail shops and car parks.

Different water storage capacities are required. A two-thirds capacity reduction was allowed because there is a direct telephone link to the fire brigade. Storage capacities used are 55 m3 for OH group I, 95 m3 for OH group II, and 107 m3 for OH group III.

The sprinkler system has a combined water storage capacity and a number of pump sets serving two hazard groups (OH I and OH III). Occupancy type OH II was served by an OH III provision to give higher protection with a simpler system configuration. A 100 m3 common sprinkler tank is located at the 22/F refuge floor of Tower A for serving Towers A and B up to 33/F for OH III group or below including car park, shops, office, and hotel. The tank is fed from a town main; both ends have a common transfer tank of 20 m3 and a pump set at Basement 2. Another sprinkler tank of 25 m3 is provided at the 53/F refuge floor of Tower B to serve floors from 34/F to the roof of this tower as OH I classification. The 25 m3 tank is replenished by the common 20 m3 transfer tank and the pump at Basement 2 level. There is a 10 m3 transfer tank and pump set at 24/F refuge floor. The sprinkler inlets on the G/F are connected to the 20 m3 common transfer tank serving Towers A and B (see Figure 1).


Figure 1. Design Concept of Sprinkler System.

There are many options in designing a sprinkler system for such a supertall building. In addition to the above design that uses a “precalculated” method for determining the water storage capacity, a “full hydraulic” method can be applied. This is based on the design water discharge density, the assumed number of sprinkler heads in operation simultaneously at various fire scenarios, and the duration of the water discharge. In following the LPC design criteria for a full hydraulic system design (i.e., minimum design density of 5 mm/min and an assumed area of operation of 216 m2 for OH III occupancy), the system would satisfy the expected performance under the LPC rule. However, satisfying the design criteria specified for suppressing a fire under a U.K.-based design rule might not be applicable in the Far East. Taking public safety awareness as an example, the evacuation paths in some big hotels are piled with tabletops or even polyurethane foam decorations! Culture and education are obvious examples. Even in institutions of higher education, fighting is still a common reaction when different opinions arise.26 Emotional and disorderly reactions are somewhat different from those of the Western countries. How can normal citizens follow the rule? Therefore, further research is necessary to verify that overseas practices are applicable.

This project is funded by the Croucher Foundation on “Active Fire Protection in Supertall Buildings,” account number H-2H46.

References

1. Codes of Practice for Minimum Fire Service Installations and Equipment and Inspection, Testing and Maintenance of Installations and Equipment, Fire Services Department, Hong Kong, 2005.

2. BS 5306-2, 1990, Fire Extinguishing Installations and Equipment on Premises-Part 2 Specifications for Sprinkler Systems, British Standard Institute, U.K.

3. Rules for automatic sprinkler installations, Circular Letter 2/94, Fire Services Department, Hong Kong, 1994.

4. BS 7974-0, 2001, Application of Fire Safety Engineering Principles to the Design of Buildings-Code of Practice, British Standard Institute, U.K.

5. Performance Code for Buildings and Facilities User’s Guide, International Code Council, Mass., 2001.

6. International Fire Engineering Guidelines, Australian Building Code Board, Australia, 2005.

7. Buildings Department, 1998, PNAP 204 Guide to fire engineering approach, Practice Note to Authorised Persons and Registered Structural Engineers, Buildings Department, Hong Kong.

8. Buildings Department, 2004, Code of Practice for the Provision of Means of Access for Firefighting and Rescue, Buildings Department, HKSAR.

9. Chow, W.K., “Fire safety in green or sustainable buildings: Application of the fire engineering approach in Hong Kong,” Architectural Science Review, 2003; 46:3, 297-303.

10. Chow, W.K., “A preliminary discussion on engineering performance-based fire codes in the Hong Kong Special Administrative Region,” International Journal on Engineering Performance-Based Fire Codes, 1999; 1:1,1-10.

11. Tsui, Fiona S.C. and Chow, W.K., 2006, Performance-based design of sprinkler systems, Proceedings of Sichuan – Hong Kong Joint Symposium 2006, 30 June – 1 July 2006, Chengdu, China, p. 147-157.

12. Chow, W.K. and P.L. Ho, “Thermal responses of sprinkler head,” Building Services Engineering Research and Technology, 1990; 11:2, 37-47.

13. Building Ordinance Cap.123, Department of Justice, Government of the Hong Kong Special Administrative Region, 2004, http://www.legislation. gov.hk/ eng/home.htm.

14. Chow, W.K. “On the sprinkler tank size and fast response sprinkler head,” International Journal on Engineering Performance-Based Fire Codes, 2000; 2:4, 124-126.

15. BS 5588 Series, 1990-1998, Fire precautions in the design, constructions and use of buildings, British Standard Institute, U.K.

16. PD 7974-4, 2003, Application of Fire Safety Engineering Principles to the Design of Buildings – Detection of fire and activation of fire protection systems (Sub-system 4), British Standard Institute, U.K.

17. Richardson, J.D. and I. Oleszkiewicz, “Fire tests on window assemblies protected by automatic sprinklers,” Fire Technology, May 1987; 23:2, 115-132.

18. Kim, A.K. and G.D. Lougheed, “Fire protection of windows using sprinklers,” Construction Technology Updated No. 12, National Fire Research Council of Canada, Dec. 1997.

19. Chow, W.K., 2005, Building fire safety in the Far East, Architectural Science Review, 48: 4, 285-294.

20. PD 7974-6, 2004, Application of Fire Safety Engineering Principles to the Design of Building-Human Factors: Life Safety Strategies-Occupant Evacuation, Behavior and Condition (Sub-system 6), British Standard Institute, U.K.

21. The Building Regulations 1991 Fire Safety, Approved Document B, Department of the Environment and Transport Regions, U.K., 2000.

22. Building Code of Australia 2006, Australian Building Code Board, Australia.

23. Melinek, S.J., “Effectiveness of sprinklers in reducing fire severity,” Fire Safety Journal, 1993; 21:4, 299-311.

24. Chow, W.K., “Comment on estimating heat release rate for a design fire in sprinkler protected area,” International Journal on Engineering Performance-Based Fire Codes, 2005; 7:1, 1-5.

25. Russell, P.F., “Fire sprinklers in performance-based building design,” Proceedings of the 5th International Conference on Performance-Based Codes and Fire Safety Design Methods, 6-8 October 2004, European Commission Facilities, Luxembourg, USA, Society of Fire Protection Engineers, 173-182.

26. “Fighting at university president selection forum,” Commons Daily, Taiwan, Dec. 23, 2005, A01.

W.K. CHOW is a chair professor of architectural science and fire engineering; principal investigator, Fire Safety Engineering; and director of the Research Centre for Fire Engineering at the Department of Building Services Engineering, The Hong Kong Polytechnic University. He is also the founding president of the Society of Fire Protection Engineers-Hong Kong Chapter; technical advisor to the IFireE-Hong Kong Branch; guest professor and supervisor of doctoral degree candidates for the University of Science and Technology of China and Harbin Engineering University; and visiting professor to the Beijing University of Technology and the Beijing Municipal Institute of Labor Protection. He has had published more than 600 papers in journals and conference proceedings.

FIONA S.C. TSUI is a senior engineer with Arup Fire, Ove Arup & Partners Hong Kong Limited. She has more than 12 years of experience as a consultant in fire safety engineering and building services engineering.

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