, Volume 4, Number 3, p.141-146, 2003 ASSESSING FIRE SAFETY PROVISIONS FOR SATISFYING GREEN OR SUSTAINABLE BUILDING DESIGN CRITERIA: PRELIMINARY SUGGESTIONS C.L. Chow and W.K. Chow Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong, China (Received 26 February 2003; Accepted 21 July 2003) ABSTRACT The construction industry all over the world is moving towards constructing green or sustainable buildings. To satisfy the proposed assessment criteria, new architectural features and concepts, new mechanical and electrical systems, and appropriate energy and environment management scheme have been proposed. However, fire safety aspects have not yet been assessed properly. There had been numerous conflicts between the green or sustainable building design and fire safety provisions. In this paper, an assessment scheme on whether the fire safety provisions have been designed and operated by paying attention to criteria for green or sustainable buildings based on the following is proposed: Passive building construction. Active fire protection system. Fire safety management. Total mark of the scheme is 0, with 0 marks allocated to items on fire safety management, 2 marks to passive building construction, and 2 marks to active fire protection system. Views from local professionals are now sought. Marks for each item are then tuned after summarizing their feedbacks. 1. INTRODUCTION Most of the professionals in the construction industry are dealing with green buildings or sustainable buildings in advanced countries including Hong Kong. Green buildings are of great interest to advanced countries towards the end of the last century. Now, this is extended further to sustainable buildings [e.g. 1]. Although the concepts behind the two are different as green building deals with relative scale to a typical building in a region, and sustainable building is more absolute on controlling energy and mass flows internationally, the assessment procedure is roughly the same [2]. Basically, works should be carried out in three areas [e.g. 3] to provide green or sustainable buildings: Architectural features including building construction element. Electrical and mechanical systems to give comfortable environment, but the system would use energy, directly or indirectly. Management including energy management, environmental management and fire safety management. There had been numerous arguments on whether building assessment methods should be focused on environmental performance or sustainability [e.g. 2,4]. However, the most important part on the safety aspect has not yet clearly spelled out []. Note that most likely, prescriptive fire safety codes are not updated frequently. In fact, some new buildings with green features had failed to satisfy those prescriptive codes in the past few years. The hidden adverse effects on safety of those green building designs in Hong Kong had been pointed out [e.g. 6]. Similar to any other design [7] for fire safety provisions, three areas have to be considered also for green buildings or sustainable buildings [8]: Passive building construction Passive building constructions such as compartmentation, fire resistance construction, means of escape for occupants and means of access for firefighters have to be provided for fire protection. The objectives [9-11] are to reduce the chance of having an accidental fire by making the building materials and components difficult to ignite. Even if the material is ignited, small amount of heat will be given out at the early stage of a fire. If a fire occurs, the spreading rate should be slow. 141
It is targeted to confine the fire within the place of origin without affecting the adjacent areas. The building structure should be able to stand the fire for some time so that occupants can evacuate. Active fire protection system Active fire protection systems are for detecting a fire, giving early warning and reporting to the management and fire brigade, and also attempting to control the fire. Three terms [e.g. 12] should be distinguished clearly: control means the heat release rate of fire is not allowed to grow with a rapid rate; suppression means the heat release rate is reduced; extinguishment means the burning is stopped. Systems for achieving the objectives as in above have to be clearly spelled out, especially in tall buildings where only fire alarm and detection system, fire hydrant system and hosereel system are normally required [e.g. 13]. Water is used extensively and must be designed to satisfy the water conservation criteria for green buildings. Smoke management system necessary for basements, car parks or big halls should be design carefully as smoke discharged would give environmental adverse effects. Gas protection systems should be designed carefully, but might only be installed in buildings of special uses. Even so, total flooding system with agents giving greenhouse effects (measured by global warning potential GWP) and damaging the upper atmospheric ozone layer (measured by ozone depletion potential ODP) should be avoided. Fire safety management Passive building construction and active fire protection system are the hardware provisions as in a computer system. These might not necessarily provide adequate fire safety. Good management [14] schemes (like good software in a computer system) should be provided in a total fire safety concept. Basically, a fire safety plan [e.g. 1] can be prepared by the building operation team, which includes a maintenance plan; a staff training plan; a fire prevention plan; and a fire action plan. The first two areas are similar to computer hardware in information technology. The last area is similar to software programming. Good design of safety management scheme can give adequate fire safety eventhough the hardware provisions are not updated to match with the advances in fire technology. For example, it is difficult to allocate spaces in old buildings to house a sprinkler water tank if such facility is suddenly required. In this paper, how fire safety provision can cope with green or sustainable buildings design criteria following the above three areas is highlighted. An assessment scheme is proposed for judging whether the fire safety design complies with the green or sustainable building design criteria. Further field surveying studies should be carried out. 2. ACTIONS ON THE THREE AREAS It was proposed recently [8] that green buildings criteria can be satisfied by taking appropriate actions as: For passive building construction - Recycling waste materials might give adequate fire resistance period for compartmentation. - Evacuation paths can be integrated with vertical shafts for providing natural ventilation in highrise buildings with air flow driven by stack effect. - Application of nanocomposites as intumescent fire retardants (IFRs) [e.g. 16] would reduce using excessive amount of halogen to stop key combustion reactions in the burning process. For active fire protection system - Substitution of halon gas protection system by water mist fire suppression system [e.g. 12] would give better environmental protection and reduce the amount of water used in traditional sprinkler systems. - Clean agents with zero ODP and low GWP such as heptafluoropropane [e.g 17] should be considered. - Recycling water to be used for traditional water systems. - Using intelligent fire detection systems integrated with local application system instead of total flooding system can determine the type of accidental fire and calculate the adequate amount of extinguishing agent, which would help in limiting the use of agent and reducing the potential damaging effect to the environment. 142
On fire safety management Preparing a good fire safety plan [14,1] with clear procedures on maintenance plan, staff training plan, fire prevention plan and fire action plan would reduce the chance of having an accidental fire. Even when such a fire occurs, good fire safety management would ensure that the fire can be confined within a small area. Appropriate amount of fire suppression agents would be discharged at the right time. Toxic gases such as carbon monoxide (CO), carbon dioxide (CO 2 ) and nitrogen oxides (NO x ) generated would be limited to low level with little damaging effect to the environment. Taking the above suggested actions [e.g. 8] on the three aspects would satisfy the following criteria on green buildings [e.g. 18,19]: Energy saving - Reduce the use of energy for operating the mechanical heating and cooling systems with better building thermal insulation (such as reducing the overall thermal transfer value OTTV in Hong Kong) [20] of the building envelope; but transition to flashover in case of an accidental fire while using those thermal lagging designs must be considered. - Air flow paths for providing natural ventilation [21] integrated with evacuation design [9,]. Water consumption - Use less amount of water to suppress a fire by a water mist system. - Use of waste or recycle water for traditional water systems. Environment protection - Reduce the level of pollutants such as CO, CO 2 and NO x discharged from a fire. - Use of clean agents such as heptafluoropropane. - Use less amount of extinguishing agent by designing the system properly without oversizing the requirement. - Use of halogen-free IFRs [16]. - Reduce the amount of fire retardants by nanocomposites. Waste management - Recycling more waste materials for construction elements with adequate fire resistance period [e.g. 11]. A pictorial presentation is shown in Fig. 1. Hardware Software Reduce the chance of fire occurrence Limit the fire size Reduce the emission of CO, CO 2 and NO x Fire Safety Management Passive Building Construction Active Fire Protection System Use of waste materials for compartmentation to have adequate fire resistance period Nanocomposites as fire retardants Integration of evacuation path with openings for natural ventilation provision Using less amount of water by water mist system Use waste or recycle water for traditional water systems Use clean agent with zero ODP and low GWP Local application system instead of total flooding system Intelligent fire detection system to discharge adequate, not more nor less, agents Fig. 1: Overall view of fire safety on green building designs 143
3. PROPOSED MARKING SCHEME To assess whether the fire safety provisions are designed with reference to green or sustainable building criteria, a marking scheme is proposed as in Table 1. Note that all the items as suggested in above were allocated with marks based on fire professional experience, local demand, views from building owners and occupants, feasibility of implementation, ease of operation, disturbance to normal operation of the building and of course, the associated cost. This scheme had been discussed preliminarily with some building professionals through interviews. The proposed assessment scheme is now presented for further comments from the general public. The marking scheme will be revised according to the comments and feedback. A total mark of 0 is recommended. Since software management is so important, therefore it is assigned with 0 marks. On the hardware provisions, equal marks of 2 are allocated to the two items on passive building construction and active fire protection as they are of equal importance. Table 1: Mark distribution Item Action Point Hardware: 0 Passive building construction: 2 Use of waste materials for compartmentation to give adequate fire resistance period Integration of evacuation path with openings for natural ventilation provision Nanocomposites as fire retardants for protecting insulation materials with foam Use of asbestos for fire protection or thermal lagging - Active fire protection system: 2 Using less amount of water by water mist system Use waste or recycle water for traditional water systems Use clean agent with zero ODP and low GWP Local application system instead of total flooding system Intelligent fire detection system to discharge adequate, not more nor less, agents Use of chemical agents with ODP Oversize the water system Design of smoke exhaust system without smoke treatment plant - - - Software: 0 Fire safety management: 0 Good maintenance plan to ensure passive building construction elements are in proper order; and active fire protection systems are checked regularly Reduce the chance of fire occurrence with proper fire prevention plan Limit the fire size with good fire action plan Reduce the emission of CO, CO 2 and NO x by adequate staff training in order not to use the wrong system 20 Storage of excessive combustibles with potential to give big fire, if the building is not used as a godown - 144
Note that the marks allocated are for assessing whether the fire safety provisions are designed with consideration to green or sustainable buildings. That does not imply that buildings with low scores are not safe. This is only a reflection that more attention can be paid on improving the green or sustainability aspects. Because of that, negative marks are proposed for fire safety provisions with potential damage to the environment. Using chemical agents such as halon for gas protection systems is an example. Basically, a fire safety plan should be worked out as described in above. In the fire prevention plan, there should be management schemes in reducing the chance of having an accidental fire. All the items such as low-cost power supply adaptors for converting voltage from 1 to 220 V or vice versa, should be replaced regularly. In the staff training plan, staff should be trained not to use the wrong extinguishers nor discharging too much agents. This would also reduce the emission rate of gases such as CO, CO 2 and NO x. A good fire action plan would ensure that staff can take appropriate action to limit the fire size. On the passive building construction design, use of waste materials with appropriate fire retardants would give construction elements such as partition materials with adequate fire resistance. Natural ventilation provision is now commonly designed in green buildings. Some of the air flow paths would be constructed in the vertical directions for tall buildings. Evacuation paths can be integrated with those vertical ventilation shafts. On the active fire protection systems, adequate water, not more nor less, should be used. Water mist fire suppression system is a good candidate, though it should be assessed properly as an illdesigned system would not be able to extinguish a fire rapidly. It might even enhance combustion while acting on some fuels. Large quantity of water would be required for traditional water hosereel or fire hydrants systems in comparing with water mist system. Alternative sources such as waste water, recycle water and rain water should be considered in operating them. Wherever gas protection systems are used, local application system instead of total fluidizing system should be considered first. Overflooding the whole space with chemical agents such as CO 2 would be hazardous to the environment. Intelligent fire detection system can be used so that it would not just detect a fire and give warning, but also instruct to take appropriate actions such as commanding a water gun in an atrium to act at the fire with correct angles and discharge flow rates. A video fire detection system would be very helpful. Actually, all the items can be divided into design and operation issues with responsibilities taken care of by the building designer and the facilities managers respectively. 4. CONCLUSION An assessment scheme is proposed for inspecting whether fire safety provisions in buildings satisfy the criteria for green or sustainable buildings. Both design consideration and operation schemes are included. Areas of interest to the building services engineering industry, i.e. environment protection, energy saving, water conservation and waste management are outlined. Basically, three aspects [e.g. 3,7,8] on passive building construction, active fire protection system and fire safety management should be considered. Fire safety management [14,1] is even more important than the other two [9-11,13]. The concept is analogous to using good software in controlling hardware in a computer system. Note that staff training is a key element. The proposed scheme would help the industry in designing and operating fire safety provisions for buildings towards the green or sustainable criteria [1,2,18]. Once again, those buildings with lower grades do not mean they are not safe in a fire. This is a measure on the design towards green or sustainable buildings. The attributes concerned and weighting of each parameter are just proposed for writing up a more detailed marking scheme. Comments are welcome and in fact, the decision making depends on the policy of the authority, responsibilities of the professionals and as well, the demand from the society. As stated in the literature [e.g. 1], collective action of attempting to protect the environment, even for controlling big fires with small chances to occur, would make the earth clean and continue to survive as a living planet. REFERENCES 1. Sustainable Building 2002: Proceedings of the 3 rd International Conference on Sustainable Building, Oslo, Norway, September 23-2 (2002). 2. R.J. Cole, Building environmental assessment methods: clarifying intentions, Building Research & Information, Vol. 27, No. 4/, pp. 230-246 (1999). 3. W.K. 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