【正文】 et al,1993)? Lift ponents can be affected by heat, smoke and water (Klote et al, 1993)? Power failure (Klote et al, 1993)? Potential of lifts opening onto the fire floor? The evacuation needs to be controlled and coordinated and the number ofoccupants entering the lift needs to be regulated? Lift shafts can act as chimneys exposing occupants to heat and smoke.? Occupants have been told for the last 20 years not to use lifts in a fire (Klote etal, 1993)? Pressure differentials in lift shafts can vary with building geometry and atdifferent floors (Klote, 1983)? Lift microprocessor controls are very sensitive to heat (Semple, 1993)? Fire brigade shutting off the power can be a problem. Batteries will only run for alimited length of time (Semple, 1993).? Malfunctions in an emergency could lead to litigation (Semple, 1993).? There is limited opportunity for rescue of people trapped between floors (Pauls etal, 1991)The some of the other reasons why lifts are unsafe stated in the ASME Elevator Code and Handbook (Cote, 1997) are:? Occupants may push a button and waste valuable time waiting for a lift that maynot arrive? Lifts can not start until the car and hoistway (lift shaft) doors are closed.Overcrowding may prevent these doors from closing? A lift occupant could press the incorrect button? Normal functioning of lifts such as high or low call reversal may occur at the fireFloorThe NFPA Life Safety Code (Cote, 1997) does not recognise lifts as a typical means of escape, but it does allow their use under certain circumstances. If a lift plies with Section 74 of the Code, it is permitted as a second means of egress, provided:? The building and surrounding structure is protected throughout by an automaticsprinkler system? The building is subject to an occupancy of no more than 90 people? Primary egress discharges directly to the outside? There are no high hazard content areas in the building or attached structures? 100% of the egress capacity shall be provided independent of the lifts? An evacuation plan is implemented specifically including the liftThe most immediate application for the use of lifts, in the evacuation of apartment buildings, is for the evacuation of disabled and elderly occupants and the evacuation of low occupancy highrise apartments.The escape times for lift egress can be calculated from the following formula (Klote et al,1993)Klote et al (1993) found that the use of lifts for egress decreases building evacuation times by between 10 and 50%. Greater evacuation efficiency occurs as the height of the building increases. The timesavings are a result of using a bination of lifts and stairs for evacuation. A similar result was found by Andersson and Wadensten (2000), in their simulations of the One Canada Square building at Canary Wharf in London, where they found that lifts improved the evacuation procedures in the building.The following are 13 criteria for safe lift egress design proposed by Chapman (1994)1. The building be fully sprinkler protected2. Lift shafts should be pressurised3. Lift lobbies on all floors should be enclosed4. Lift lobbies should be pressurised5. Lift and lobby pressurisation intakes should be in a smoke free location6. All lift lobbies should be protected by smoke detectors7. Lift systems should be made water resistant8. When a power failure occurs all lifts should return to their designated level9. All lifts should be able to be operated from a designated emergency powergenerator10. All lift lobbies should have access to a pressurised stair, without the occupantshaving to pass through a fire area11. All lift cars should have a means of two way munication12. All lift lobbies should have a means of two way munication13. A program specifying the priority of lift response during a fire should bedeveloped.For lifts to be effective in evacuations, some other design concepts that should be considered are:? Smoke and fire separation of lift machine room and lift shaft (Klote, 1993, Kloteet al, 1995, Levin and Groner, 1994)? Analogue addressable detection system linked to lift control to prevent liftstopping on fire floors and to prioritise floors for evacuation (Klote et al, 1995,Levin and Groner, 1994)? Automatically recall lift if a fault is detected (Klote, 1993, Klote et al, 1995,Levin and Groner, 1994)? Wardens or security staff to direct evacuations, reassure occupants and prioritisewho uses the lifts, and also to control occupant numbers in the lifts (Klote et al,1995, Levin and Groner, 1994)? Provide a system to prevent the lift stopping on floors where heat is detected, orproviding fire rated lobbies on all floors (Klote et al, 1995, Levin and Groner,1994)? Higher levels of protection for lift system, if building is non sprinkler protected(Klote et al, 1995)? Load weighting device, so lift bypasses all other calls when fully loaded(Fox,1991)? Lifts connected to alarm panel and sent to the top floor in an emergency and onlyresponding to calls in the down direction (Fox, 1991)? Have machine room close to ground level, therefore if occupants are trapped inthe lift the time to access machine room is reduced (Gatfield, 1991).? Reduce lobby sizes to prevent storage of bustible materials. BS5588 Part 5limits the lift lobby to between 520m2 (Gatfield, 1991)In some cases occupants may prefer to use lifts, instead of stairs, for egress due to thephysical exertion of walking down several flights of stairs (Klote et al 1993). In the Forest Lane fire, 40% of the respondents said they used the lifts (Proulx et al, 1995). This included people who were assisted by rescue personnel and occupants who were not successful.Occupants also prefer to use entry points as exit points due to familiarity. Therefore, as lifts are the main point of entry for the occupants, they will be familiar with them and may prefe