LIFT TRAFFIC ANALYSIS
ABD. JAMAL OTHMAN
HOPT 4, CKK, IPJKR
TEL : 03- 92354640
Email : oajamal@jkr.gov.my
Users Expectation on Vertical Transportation
Lighting
Stopping
accuracy
Ride Comfort
Safety
Interior
Waiting finishes
time
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3
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Lift Traffic Analysis
GENERAL CONSIDERATION
• Application
• Office building/Hospital/commercial
• Capacity & Nos. Of Lift
• Traffic and size of building
• Speed of lift
• Number of stops and traffic load
• Lift Doors
• Depends on application
• Number of stops/opening
• Depends on building height, applications
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Lift Traffic Analysis
• Other Requirement
• Electrical switch boards and power points in lift motor rooms
• Ventillation fans and lightings in machine rooms
• Cat Ladders and power points in lift pits
• Structural openings in lift motor rooms, hoistways etc.
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Lift Traffic Analysis
• Assessment of demand
• Traffic patterns (in an office building)
• Morning UP peak
• Evening DOWN peak
• Two-way traffic (lunch periods)
• Interfloor traffic
• Other considerations, e.g. ‘Flexitime’ attendance
• Estimation of population (occupant density)
• Estimation of arrival rate
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Traffic pattern in an office building
[Source: CIBSE Guide D]
Up peak traffic profile
[Source: CIBSE Guide D]
Down peak traffic profile
[Source: CIBSE Guide D]
Estimation of population
Building type Estimated population
Hotel 1.5-1.9 persons/room
Flats 1.5-1.9 persons/bedroom
Hospital 3.0 persons/bedspace*
School 0.8-1.2 m2 net area/pupil
Office (multiple
tenancy): 10-12 m2 net area/person
- Regular 15-18 m2 net area/person
- Prestige
Office (single tenancy):
- Regular 8-10 m2 net area/person
- Prestige 12-20 m2 net area/person
* excluding patient
[Source: CIBSE Guide D]
Percentage arrival rates and up-peak intervals
Building type Arrival rate (%) Interval (sec)
Hotel 10-15 30-50
Flats 5-7 40-90
Hospital 8-10 30-50
School 15-25 30-50
Office (multiple tenancy):
- Regular 11-15 25-30
- Prestige 15-17 20-25
Office (single tenancy):
- Regular 15 25-30
- Prestige 15-17 20-25
[Source: CIBSE Guide D]
Lift Traffic Analysis
• Estimation of quality of service
• Actual average passenger waiting time (AWT)
• Time between the instant of passenger arrival until the instant of the actual arrival of the lift
• Shorter the waiting time, better the service
• But cannot be measured easily
• Interval of car arrivals at the main terminal
• Often taken to estimate the probable quality of service
• A part of the evaluation of handling capacity
• AWT ≈ 85% of the interval (assumed 80% car loading)
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Lift Traffic Analysis
• Lift traffic calculations
(1) Based on classical formulae & results
• For the worst 5-min period during morning up peak
(2)Based on a discrete digital simulation of the building, its lifts and the
passenger dynamics
Such as for down peak, two-way & inter floor traffic
Need to work at early design stage with architect or planner and the client to
establish the lift system & its design criteria.
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Probable quality of service in office buildings
Interval (sec) Quality of service
20 Excellent
25 Very good
30 Good
40 Poor
50 Unsatisfactory
[Source: CIBSE Guide D]
Lift Traffic Analysis
Calculate up peak performance
• Determine round trip time (RTT)
• Time for a single lift to make a round trip
• Select number of lifts (L)
• Determine up peak interval (UPPINT)
• Such as, <= 30 sec (good)
• Determine up peak handling capacity (UPPHC)
• During the worst 5-min (300 sec) of up peak
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Lift Traffic Analysis
• RTT = 2 H tv + (S + 1) ts + 2 P tp
• H = average highest call reversal floor
• tv = single floor transit time (s)
• S = average no. of stops
• ts = time consumed when stopping (s)
• P = average no. of passengers carried
• tp = passenger transfer time (s)
• UPPINT = RTT / L
• UPPHC = (300 x P) / (UPPINT x U)
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Lift Traffic Analysis
• Parameters in RTT equation
• Average no. of passengers (P)
• P = 0.8 x rate capacity of lift car
• Average highest call reversal floor (H)
N 1 P
i
H N
i 1 N
• Average no. of stops (S)
1
P
S N 1 1
N
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N 1 P
i
H N
i 1 N
N-1 j P
• H=N–Σ( Σ U1
U
)
J=1 i=1
• N = Number of floors above terminal floor to
• be served by the lift system.
• U = Total population in the building
• U1 = Population at floor
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1
P
S N 1 1
N
N P
• S=N–Σ( 1- UU )
1
i=1
• N = Number of floors above terminal floor to
• be served by the lift system.
• U = Total population in the building
• U1 = Population at floor
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Lift Traffic Analysis
• Parameters in RTT equation (cont’d)
• Single floor transit time, tv = df / v
• df = average interfloor distance (m)
• v = contract (rated) speed (m/s)
• For a lift serving an upper zone, an extra time to make the jump to/from the
express zone to the main terminal must be added:
RTT = 2 H tv + (S + 1) ts + 2 P tp + [2 He tv]
• He = number of average height floors passed through to reach the first served
floor of the express zone
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Lift Traffic Analysis
• Parameters in RTT equation (cont’d)
• Time consumed when stopping
ts = T - tv = tf(1) + tc + to - tv
• T = floor-to-floor cycle time (s)
• tf(1) = single floor flight time (s)
• tc = door closing time (s)
• to = door opening time (s)
• Floor cycle time (T) has the most effect on RTT
• Can be used to judge the quality of service
• For a good system, T = 9 to 10 sec
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Minimum Door Opening Times
Door Size
Panel arrangement 0.8m 1.1m
Side Opening 2.5s 3.0s
Centre Opening 2.0s 2.5s
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Minimum Door Closing Times
Door Size
Panel arrangement 0.8m 1.1m
Side Opening 3.0s 4.0s
Centre Opening 2.0s 3.0s
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Guide to selection of lift contract speed
Contract Speed (m/s) Lift Travel (m)
< 1.00 < 20
1.00 20
1.50 30
2.50 45
3.50 60
5.00 120
>5.0 >180
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Lift Traffic Analysis
• Parameters in RTT equation (cont’d)
• Passenger transfer time (tp)
• Vague to define
• Depends on:
• Shape of lift car
• Size and type of car entrance
• Environment (commercial, institutional, residential)
• Type of passenger (age, gender, purpose, etc)
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Lift Traffic Analysis
• Assumptions of RTT equation
• Average no. of passengers
• Passengers arrive uniformly in time
• All floors equally populated
• All cars load to 80%
• Rated speed reached in a single floor jump and interfloor height are
equal
• Other operating time (like dwell time) ignored
• Traffic controller is ‘ideal’
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Lift Traffic Analysis
• Average passenger waiting time (AWT)
• Average time an individual passenger waits at a floor before being
able to board a lift
• Not dependent solely on UPPINT
• Also affected by the average car load and the arrival probability distribution
function
• Some design criteria for different traffic patterns have been derived
empirically based on the simulation method (see CIBSE Guide D)
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Lift Traffic Analysis
– Basic simple criteria
• Average waiting time is 30 to 60 seconds. Common users expectation.
• Average Max 5 stops per lift.
• Max travel time for the lift to return to ground floor from highest floor is
60 seconds. Therefore, lift speed is set based on this criteria.
• 20% of floor population weight is equal to about 80% of the per lift
capacity. Per person weight is 68Kg.
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Lift Traffic Analysis
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• SEKIAN
• TERIMA KASIH
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