1. Vertical Transportation Elevator Design Consideration Elevator Selection Parameters

2. Introduction
The selection of the vertical transportation equipment is the most important decision to be made by the designer
The passenger, freight elevators and elevator

3. Passenger Elevators Ideal performance:
Minimum waiting time for car at any floor level
Comfortable acceleration
Rapid transportation
Smooth and rapid parking
Accurate automatic leveling at ladings
Rapid loading and unloading at all stops

4. Architectural Impact
Cars and shaft way doors must be treated in a manner consonant with the architectural unit of the building
Integration of shaft way into the building is a prime factor in composition as is the design of elevator lobby

5. Codes and Standards ANSI/ASME NFPA 101
A17.3 existing elevators and escalators
A17.4 –emergency evacuation of passengers from elevators
ANSI A117.1 –accessible and usable buildings and facilities
NFPA 101

6. Elevator Equipment Principle equipment The car Safety doors
Operating control equipment, floor level indicator
Illumination
Emergency exits and ventilation

7. Cables (Ropes)
The minimum safety factor varies for for passenger elevators and for freight elevators

8. Counterweight
Its value is equal to that of the empty car plus 40% of the rated live load
It serves several purposes:
To provide adequate traction at the sheave for car lifting
Reduce the size of the traction machine
Reduce power demand and energy cost
75% of the energy expended in lifting a car is returned to the system by regeneration when the car is lowered

9. Control Equipment
Drive control- concerned with the velocity, acceleration , position determination and leveling of the car
Operating control covers car doors operation and functioning or car signals, including floor call buttons and all indicating devices
Supervisory control is concerned-car installations

10. Shaft
The hoist way is the vertical passage way for the car and counterweights

11. Gearless Traction Machine
It consists of a DC or AC motor, the shaft of which is directly connected to a brake wheel and driving sheave
The motor must run at the same low speed as the driving sheave
They are used for passenger service , car capacity of 2000 ib-4000 lb.
Below 500 fpm geared machine are used

12. Geared Traction Machine
It a worm and gear interposed between the driving motor and the hoisting sheave

13. Safety devices A dual safety system designed to stop an
The main break of an elevator is mounted directly on the shaft of the machine
A dual safety system designed to stop an
elevator car automatically before
its speed becomes excessive is normally used

14. Elevator Doors
The choice of the car door affects the speed and quality of elevator service considerably
Installations can be equipped with an electronic sensing device that detects passengers in a wide area on the landing in front of the car door rather than only directly in the door’s path
Such detection often accompanied by audible signal, causes the car door to remain open for a predetermined length of time or a closing door to reverse

15. Requirements for the disabled
Elevator manufacturers follow ADA additional conveniences for the disabled as the specific facility design intent or local codes require

16. Elevator Design Procedure

17. Example Problem
Design an elevator system for a 12 story, single purpose tenant , office building that provides an excellent level of service
Construction level is “normal”
Floor height:12-0 floor to floor
Floor are : net square feet (nsf) each

18. 1. Determine the percent handling capacity
Office building
Single purpose
table

19. Table Minimum Handling Capacities (HC)
Facility
Percent of Population to be Carried in 5 min
Office buildings
Center city
12-14
Investment
Single purpose
14-16
Residential
Prestige
5-7
Other
6-8
due to more urgent demands, particularly at the school and work exodus
Dormitories
10-11
Hotels-1st quality
12-15
Hotels – 2nd quality
10-12

20. Range 14-16%
Assume it 15%
PHC=0.15

21. 2. Determine the Interval (I)
Table 31.4 Recommended Elevator Intervals
and Related Lobby Waiting Time

22. Facility type
Interval (sec)
Waiting time (sec) Based on the relationship: waiting time = 0.6x interval
Office building
Excellent service
15-24
9-14
Good service
25-29
14-17
Fair service
30-39
18-23
Poor service
40-49
24-29
Unacceptable service
50+
30+
Residential
Prestige apartments
50-70
30-42
Middle-income apartments
60-80
36-48
Low-income apartment
80-120
48-72
Dormitories
Hotels-1st quality
30-50
18-30
Hotels -2nd quality

23. Office building “excellent” service
I=15-24 sec

24. 3. Determine the population
Table Population of typical buildings for estimating elevator and escalator requirements

25. Building type
Net area
Office buildings
Square feet per person
Diversified (multiple tenancy)
Normal
Prestige
Single tenancy
normal
90-110
prestige
Hotels
Persons per sleeping room
Normal use
1.3
Conventions
1.9
Hospitals
Visitors and staff per bed
General private 3
General public (large Wards)
3-4
Apartment Houses
Persons per bedroom
High-rental housing
Moderate-rental housing
1.5
2.0

26. Office building
Single tenant
Normal construction
Range from sf/person
Assume 100 sf/person

27. 4. Determine the handling capacity (HC)
PHC=0.15
HC=0.15 x 1100
HC =165 persons

28. 5. Determine rise and select Car
Table (31.9)
Elevator Equipment Recommendations

29. Building type
Car capacity, lb
Rise , ft
Maximum car speed, ft/sec
Office building
2500
0-125
3000
35000
700
800

30. 11 floors (above lobby)
12-0 (floor-floor)
Rise=11x12-0
Rise = 132 feet
Select a Car:
2500 # 500 fpm

31. 6. Determine the average trip time (AVTRP)
12 – 0 floor –floor
2500 # car
500 fpm
11 floors
From fig the round time is about 65 sec

32. 7. Determine the round trip time
12 – 0 floor – floor
2500 # car
500 fpm
11 floors
From fig the round time is about 120 sec

33. 8. Verify single car capacity (P)
Elevator capacity (lb)
Maximum Passenger Capacity
Normal Passenger Load per trip
2000 12 10
2500 17 13
3000 20 16
3500 23 19
4000 28 22

34. From Table 31.5 for a 2500 lb car the normal capacity load per trip is 13 persons
The number of passengers carried on a trip during peak conditions is approximately 80% pf the car capacity

35. 9. Determine 5 minutes handling capacity
Handling capacity (HC)= passengers/car x cars/sec x 5 min x 60 sec
HC 300 p/I
When the interval is 30 sec, the system’s handling capacity is 10 p
h=300 p /RT
h= 300x 13/120
h= 32.5 persons

36. 10. Determine number of cars
N=HC/h
N=165/32.5
N=5.07 Cars
N=5 Cars

37. 11. Confirm interval (I) I=RT/N I=120/5 I=24 Required I : 15-24 sec
Design compels

38. 12. Repeat until performance complies
In this case the performance is compliance
Use 5 cars (2500 lbs, 500 fpm)

39. System relationships
P-individual car capacity equal to 80% of the maximum during peak hours
h - 5-minute capacity of a single car
N -number of cars in a system
HC -system 5 min handling capacity, expressed in number of persons
RT -round trip time in sec
AVTRP- average trip time, sec
I- interval in sec
D – population density, in square feet per person
PHC percent of the population to be moved in 5 minutes, and expressed as percentage

40. Equations

41. Single zone systems Example
Office building downtown, diversified use, 14 rentable floors above the lobby, each ft2 net. Floor to floor height – 12 ft. determine a workable system

42. Solution From table 31.6 , recommended average HC is 13%.
From table 31.4, the maximum recommended interval is 25 sec. from table 31.7 average population density is 120 ft2 per person

43. Trial one
Building population:

44. From table 31.9 , select a car size of 3500 lb at 500 fpm

45. Then from fig 31.17c and c:

46. Single-car capacity:
From table 31.5 , we get p.

47. These figures are acceptable but we should try cars to reduce the interval.
We select 700 fpm

48. This solution is only marginally better than the previous 500 fpm solution, and the increased cost would not be justified
A trial using smaller cars with shorter RT is necessary

49. Trial 3
3000-lb cars
500fpm

50. Trial 4
3000-lb cars
500fpm
Number of cars =6

51. Both solutions are acceptable
Speed
Solution
Cars (lb)
fpm
RT (s)
AVTRP (s)
I (s)
PHC (%) 1
5 (3500)
500
155 82 31 13 2
700
151 81 30
13.5 3
5 (3000)
143 76
28.4 12 4
6 (3000)
23.8
14.4

52. 5th trial
3000 lb cars
500 fpm
RT= 143 seconds
AVTR=76 seconds
H=300(16)/143=33.6 persons
N=HC/N=182/33.6=5.4 cars
I=RT/N=140/5=28 seconds
PHC = 5*(13%)/5.3=12.3%
As expected , the improvement over the performance at 500 fpm is very slight: an interval of 28 seconds rather than 28.4 seconds and a handling capacity of 12.3% versus 12%. The large increase in first cost for gearless equipment would not be justified.

53. Multi-zone systems Less than 15 floors –one zone
More than 20 stories- two zones
From floors can be either way

54. Other elevator selection recommendations
Office buildings
Apartment buildings
Hospitals
Retail stories

55. Physical properties and spatial requirements of elevators
Shafts and lobbies
The elevator and shafts form one of the major space factors with which the architect is concerned
Proximity to other cars
Single zone
Multizone
Proximity to emergency exits/egress
Adjacent to main lobby
Dimensions and weights

56. lobby sizing Size based on peak interval 15 or 20 minute peak time
5 sf/person
From previous example using 15 minute peak
H=33.1 people/5 min→99.3 people/15 min.
Area=99.3 people x 5 sf/person=497 sf

57. Escalators Configuration
Crisscross
Stacked parallel
Spiral parallel

58. Design consideration
Lighting
Fire /Life safety