abs-lifts.pptx
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BLDGS.
ELECTROMECHANICAL MEANS OF VERTICAL
TRANSPORTATION
Elevators Design Considerations
Elevator Selection Parameters
Architectural implications
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Transportation
Need of Today: For efficient functioning of bldg.
Mandatory for 15m height. Means of vertical transport: Staircase
Lifts
Escalators
For efficient service- No. & type of lifts must take into
account several factors including: type of bldg.
nature of its occupancy
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Passenger Elevator Components
Traction Elevator
car
cables elevator machine
controls
counterweight
hoistway
rails
penthouse
pit
The principal means of vertical transport in tall
buildings is the roped elevator. It moves by a directcurrentelectric motor, which raises and lowers the
cab in a shaft with wire ropes running over a series
of sheaves at the motor and the cab itself; the
ropes terminate in a sliding counterweight that
moves up and down the same shaft as the cab,reducing the energy required to move the elevator.
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Performance Criteria
minimum waiting time
comfortable acceleration
rapid transportation
smooth/rapid slowing
accurate leveling
rapid loading/unloading
quick/quiet door operation good visual travel direction/floor indicators
easily operated controls
comfortable lighting
reliable emergency equipment
smooth/safe operation of mechanical equipment
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Classification
Elevators
Passenger
Freight
Special service
Escalators
Passenger elevators range in:
capacity : 910 to 2,275 kilograms (2,000 to 5,000pounds)
Speed: 90 to 510 metres per minute
freight elevators
hold up to 4,500 kilograms (10,000 pounds).
speed of elevators is limited to the current value
of 510 metres per minute by the acceleration
passengers can accept and the rate of change of
air pressure with height, which at this speed
begins to cause eardrum discomfort.
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Location:
-Sited in central area taking into account the proximity of entrance & staircases.
-Usually preferable to group no. of lifts together rather than spread them thru out.
-Although passenger walking time is saved by spreading the lifts, this is offset by the
increase in average waiting time for standing waiting than they are by walking to it.
Grouping reduces cost of installation.
-demand on lift or staircase can be increased or decreased by its placement.
-In department stores lifts to be easily seen & accessible to encourage customers to
visit the upper sales floors.
In hospitals bed lift is reqd close to the operating theatre in addition to other lifts.
-in all types of buildings lift lobby is desirable &should be large enough to allow trafficmovement in both directions on landing without being obstructed by the people
waiting for the lift.
-Lift lobbies to be visible from entrance hall but not viceversa as people tend to hold
lifts for late arrivals, causing disturbance and wear of the system.
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No of lifts:
The number and size of the lift may be related to the following:
1. The population of the bldg.
2.Type of bldg. Occupants
3.Starting & finishing time of population-whether staggered or unified.
4. No. Of floors & height
5. Position of building w.r.t public transport services. Bldg. Near traffic
terminal has more passenger peaks during arrival hours.
6. Convenience of user & tall building loading times and there should be
balance between these two factors.
Several smaller lifts provide better service than fewer larger lifts, but the
installation cost increases.
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Installation Quality of service
One lift for every 3 floors Excellent
One lift for every 4 floors Average
One lift for every 5 floors Below Average
Population
Estimate can be made from net floor area & probable population density per Sq M.
Average population density can vary betw 1 person per 4m2 & 1 person per 20 m2.
For general office building population density of 1 person per 10 m2 or net floor area
may be assumed.
Minimum No. Of Lifts for offices:
Table 11.1
Lower standard for this is acceptable for hotels and flats. Cars with less than 12
person capacity not acceptable for large group of people.
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Round trip timeTime in seconds taken by single lift to travel from the ground floor to top floor,
including probable no. of stops & return to the ground floor.
Flow rateExpressed as a % of total population requiring lift service during a 5 min peak
demand period. Surveys show that:
10%-25% population will require transportation during 5 min peak time.
12%- for buildings with staggered starting times
17%- for buildings with unified starting times.
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Interval (I) or lobby dispatch time
average time between departure of cars from lobby, Expressed in seconds
Represents RTT of one car divided by no. of cars in a common group system
Waiting time
average time spent by a passenger between arriving in the lobby and leaving
the lobby in a car.
Expressed theoretically as half this interval but in practice it is probably 3/4th of
the interval, equals (0.6 x I)
Interval (s) Quality of service25-35 Excellent
35-45 Acceptable for offices
60 Acceptable for hotels
90 Acceptable for flats
Table 11.2
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Speed (m/s) Lift travel in mts
Municipal flats Luxury flats offices Bed lifts0.25-0.375 - - - 5
0.50 30 15 10 10
0.75 45 20 15 -
1.00 55 25 20 20
1.50 - - 30 452.50 - - 45 100
3.50 - - 60 -
5.00 - - 125 -
Lift Travel
The number of floors above ground multiplied by the floor height.
Lift Speed
Recommended lift speeds for various building heights.
Table 11.3
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Passenger lift performance (based on 3.3 m floor to floor
height) lift serving all 15 floors
Interval (s) Handling
capacity
persons
No. Of cars Speed m/s 12 passenger 16 passenger 20 passenger 24 passenger
4 2.50 29
103
12
112
37
127
41
137
4 3.50 41
116
36
132
40
42
5 3.50 25 116 39
105
32
125
6 3.50 24
198
27
213
Lift performance
If the travel, speed & building population are known, the interval, no. Of lifts and
no. Of passenger to be carried by each lift may be found from the table below.
Table 11.4
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Car passenger capacity (p)
passengers per car
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Calculating Round Trip Time (Rtt or RT)
Step 1: Door opening & closing at each stop= 10 s.
Step 2: Time taken by passenger leaving or entering=10s
Step 3: Travelling time= Travel distance (m)
Speed of car (m/s)
Step 4: Add figure of step 1+2+3 gives total time taken
Step 5: Add 10% extra for unforeseen events
Recommended interval for lifts }= Refer NBC
Speed for different height of building}
Handling capacity (HC): HC=300p/I
Interval (I): I=RT/N5-min. handling capacity (h): h=300p/RT
Number of cars (N): N=HC/h
Sizing Equations
dl ( )
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Calculating Handling Capacity (HC)
H=maximum number of passengers handled in a 5
minute peak period time
Q= Average no. of passengers in a car
T= waiting interval in secondsP= Total population to be handled during peak
period H= 300 xQx100
TxP
Q is taken as 80% of max. capacity of the car.
Waiting interval T is calculated by
T= Rt
N
Rt= round trip time
N= Number of lifts
Handling Capacity (HC)
maximum number of passengers handled in a 5 minute peak period
when expressed as a percentage of the building population it is called
percent handling capacity(PHC)
ff b l ff
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Office building efficiency
net usable area as a percentage of
gross area
Elevator equipmentrecommendations building type
car capacity rise
speed
E l
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Example
A 15 storey office block has a net floor area above ground level of 8000 m2.Assuming unified starting times & population density of 1 person per m2 of netfloor area, calculate the flow rate & find out the lift speed, number & capacity oflifts.
From Table 11.2 check the quality of service:1. Flow rate: allowing 17% of population
8000 x 17 = 136 persons during 5 min peak demand period
10 x 100
2. Travel & Speed
Assuming a floor height of 3.3 m, the lift travel =14x3.3=46.2 mFrom Table 11.3, nearest travel for offices is 45m which requires a speed of 2.5 m/s.
3. No. & capacity of lifts
From table 11.4, four 24 passenger cars may be installed having a handling capacityof 137 & interval of 41s.
4. Quality of serviceFrom Table 11.2 the acceptable interval for offices is 35 & 45 sec, so, 41 s is
satisfactory. This will give waiting time of 20s.
Referring Table 11.1, one lift for every four floors give average quality of service & onthis basis four lifts for 15 storeys would give satisfactory service.
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Lobby Parameters
Proximity to other cars
single zone
multizone Proximity to emergency
exits/egress stairs
Adjacent to main lobbyMaximum Allowable No. of Elevators in One Group
The maximum allowable number of elevators in a groupis 8 for conventional group control system; the criterion
is the walking time for passengers in order to board the
elevator in time; 12 elevators in one group can be
tolerated for the case of destination control system.
L t C id ti L bb d C
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Layout Considerations: Lobby and Core
DesignLobby Design: Four car group: have 2 facing 2
Maximum 3 cars in line
Four in line depreciates service due to longer door hold open times requirement Lobby size and configuration:
Avoid walk thru lobbies
Passenger elevatorslobby width
Between 10 to 14 feet
Service Elevators: Depth of car x 2
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Electric Lifts
Principles of operation
Electric lift with traction drive consist of lift car suspended by steel ropes
which travel over grooved driving sheave.
Load on motor= wt. of car+ its load counterweight + friction
High tensile steel wire ropes used; no. of ropes between
4 to 12; Dia is between 9 & 19 mm.
Ropes
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Roping arrangements
Single wrap for a small car Single wrap for deflector pulley Double wrap traction
used for geared machines,
but may be used for gearless
machines for lower speed of
1.75-2.5 m/s .
The angle of contact of rope
with driving sheave is 140-180
deg.
As use of a diverting or deflector
pulley increases the risk of rope slip,by reducing the frictional area of the
rope with the driving sheave a
double wrap or wrapping pulley may
be used.
Used on high speed & heavily
loaded lifts.
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Roping arrangements
2:1 Roping 3:1 Roping
used for geared machines, at lower car speed
of between 1.75 and 3.0 m/s .
The car & counterweight speed equal half of
the peripheral speed of the driving sheave &this halves the load on the sheave & allows the
use of high speed motors which are cheaper
than slower speed motors.
The disadvantage is that the length of rope is
three times that reqd. for single wrap system.
used for heavy goods lift
where it is reqd to reduce the
motor power& the pressure
acting upon the bearings.
Traction
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Compensating ropes
In highrise bldgs. Above 10 storeys the rope
load transferred from the car to the
counterweight (and vice versa during cartravel) is considerable & with the car at the top
floor the rope load is trasferred to the
counterweight .
To offset this and reduce bounce
compensating ropes are suspended from theunderside of the car & the counterweight.
To accommodate the compensating ropes a
deeeper pit is reqd.
Diverting or
deflector pulley
Compensati
on ropes
Traction
sheave
Counterweight
Weighted
compensati
on sheave
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longer rope is needed, it travels round more pulleys,
resulting in higher functional resistance & hence moremaintenance is reqd.
However with machine room sited at ground floor , the
lift shaft is relieved of the weight of the winding machine
& control equipment.
the lower portion of the machine room also obviates
penetrating of roof slab & weathering.
Roping for machine room at
intermediate floor or bottom of the shaft
Drum drive
In this arrangement one set of ropes is wound clockwise
around the drum & another anti-clockwise , hence when
one set of ropes is being wrapped the other is unwrappedon the drum.
The disadvantage is that, as the height of the travel
increases, the drum become unwieldy & system is
limited to rise of upto 30m.
Over Speed Governor & Equipment
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Used to prevent the car from over speeding
due to the ropes breaking, stretching or by
some electric fault.mounted in the motor room directly above lift
shaft & is fitted with a pulley at least 300 mm
in dia driven by a governor rope.
One end of rope is attached to a braking
system underneath the car while the other end
extends upwards, wraps around the governor
pulley & extends down to a tension pulley at
the bottom & then returns to the car.
As the lift car travels the governor rope drives
the pulley.
Flyweights with spring control respond toover speed & the movement is used to break
the electrical contacts & trigger a mechanical
device which arrests governor rope to operate
the brake under the car.
Over Speed Governor & Equipment
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Winding
motors If drive transmitted thru to traction sheave is thru a worm gear , motor is known
as geared type.
If drive is by direct coupling from the motor to the driving sheave , motor is
known as gearless type. Gearless traction motors range in power from 22 kw to 83 kW, while geared
traction motors range in power from 3kW to 30kW.
Table 11.5 gives the type of lift equipment for various applications:
Type of Eqpt. Speed(m/s)
Load (kg)Passenger lift Goods lift
Travel(m)
Geared traction type
Single speed
0.25-0.80 1000 6000 0-25
Geared traction type
two speed
0.25-1.25 3000 6000 0-40
Geared traction type
variable speed
0.75-2.5 3000 6000 0-100
Gearless traction
type variable speed
1.75-8 3000 3000 0-250
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Geared Traction single speed motor
contains a worm gear & motor is either
A.C or D.C.
when car is within short distance of floor
landing brake is applied automatically to
bring the car at a smooth stop.
Geared Traction two speed motorconsists of either a motor with two separate windings or alternate separate motors
are used .
when starting the high speed windings are switched on in series with a resistor to
limit the current.
Smooth acceleration of car is obtained as the resistance field is progressivelylowered.
On approaching a floor landing the high speed winding or motor is switched off &
the low speed winding or motor, combined with a choke is switched on.
The car speed is gradually reduced until it is within a short distance of the landing
when the power is switched off & the brake is applied automatically to bring the car to
a smooth stop.
Geared Traction variable voltage motor
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Geared Traction variable voltage motor
Gives results cannot be obtained by any other system.
extreme smoothness of acceleration & retardation.
equipment consists of an a.c driven motor set which supplies d.c power
to the driving motor of the geared machine.
Gearless Traction variable voltage motor
Eqpt. essential for high speed lifts
having car speeds of 1.75 m/s &
over.
representation of best modern
practice to meet traffic conditions
demanding high efficiency.
a regulator is used in the generator
field circuit which controls the
generator output.
a variable resistor in a field circuit gradually reduces the resistance & increases thegenerator voltage to smoothly accelerate the car to full speed .
On attaining full speed, the generator voltage remains constant until the initiation
of slow down of the car.
Set of inductor switches are used to initiate the slow down & stopping of car, the
brakes being applied only when the car is stationary.
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Elevator Applications: TractionGeared Gearless
Stops: 15-60+Rise up to- 2000
Max.Speed: 2400
FPM
Stops: 5-15
Rise upto 150
Max.Speed:
500 FPM
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Details of Lift
Lift cars: made of wide range of
finishes & sometimes made to
architects design. They must be
strong & stand to wear &tear
without deterioration. No open
panels are permissible in the
enclosure within 1.8m of car floor.Openings in the ventilating panel
should not exceed 13mm. It is
normal for ventilating grills to be
fitted in the car skirting.
Machine Room
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Machine Room
should be at top of the lift shaft for best
efficiency.
Well ventilated, consideration to stop sound
transmission by providing insulation toconcrete base of the machine compressed
cork slabs.
Overhead lifting beam directly over the
machine for positioning or dismantling eqpt.
an access hatch on the floor, above the
landing thru which the eqpt. Can be lowered
for repair or replacement.
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lockable room adequate floor space for controllers, floor selectors & other eqpt. Is reqd.
Socket outlets & good electric lighting & daylighting is recommended.
Temperature shall not be below 10deg or above 40 deg & means of heating
& ventilating is reqd.
Walls & floors painted to avoid dust which can damage & cause
breakdown of the electrical circuit due to poor contacts.
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Lift Shaft
manufacturers drgs. Consulted regarding builders work for fixing steel guides,
counterweight & reqd. for door gear at floor landing.
constructed of RCC or brickwork in cement mortar, shall have sufficient strengthto carry the dead & superimposed loads.
FR of at least 1 hr. & constructed out of incombustible material.
Shaft to have opening in its structure for cables operating the lift into the room
containing the lift motor.
Size depends on size, speed of car & type of door gear;
manufacturers drgs. to be consulted.
must be plumb finished, smooth & painted to preventcollection of dust.
provision for air escape below & above moving car to
prevent air pressure building up.
smoke vent having opening of 0.1 m2 for smoke escape in
event of fire.
No other services accommodated in the shaft. clearance at top required for over travel & distance
depends on speed.
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shaft to extend below bottom landing to
form pit which permits car overtravel. Pit to be watertight & drainage should be
provided.
Buffers fixed to base, these are spring
loaded for slow speed lifts & oil loaded for
high speed lifts.
Electric mechanical brake is reqd. which is designed to fail safe.
when lift is running, brake shoes are electromechanically lifted clear of thebrake drum, overcoming the force of the coil or disc springs which apply the
brakes when the car is stationary.
The switching off of the electric supply permits the brake to be applied &
therefore fail safe if there is a failure in the supply.
Brakes
Lift Pit
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Traction Elevator
Components
Machine room
8-6 minimum clear
Bottom of Beam (OH) 17-6 206
Travel
number of floors
Pit (P)
10-1 11-5
S: p. 1439, F.31.29
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No. of
passenge
rs
Load
(Kg)
Speed
(m/s)
Shaft or
well (m)
Car (m) Depth of
pit (m)
Machine
room
4 300 0.5 1.8 x 1.3 1.800 x 800 1.400 3.700 x 1.800
6 450 0.5-
0.75
1.8x 1.6 1.300 x
1.100
1.400 4.000 x 1.800
8 600 0.5 2.0 x 1.9 1.400 x1.300
1.500 4.400 x 2.000
Table gives the various details & dimensions of small passenger lift installations:
Guides: Car & counterweight guides are machined tee sections finished to veryfine limits. Joints are spigoted & fish plated with machined surfaces on both
rails & fish plates.
are erected plumb & fastened to the lift shaft by heavy steel brackets.
For high-speed lifts the shoes may be provided with renewable nylon linings.
Car is guided on rails by means of sliding shoes or roller assemblies.
Balance Weight: consist of a rigid steel frame consisting the required no. of cast
iron weights.
Car & Counterweight buffers: Oil loaded buffers are used for lifts with speed of
1.5m/s or over & spring buffers for speeds 0 & 1 m/s. For slow speed lifts of 0
to 0.25 m/s it is permissible to use timber or cellular polyurathane buffers.
Landing Doors Two sets of doors reqd:
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single slide (24-36)
center opening (42-60)
two-speed, side opening (42)
two-speed, center opening (60)
mechanically interlocked & operated by the car doors,
driven by an electric motor having speed reduction
unit with clutch drive & connecting mechanism.
The power unit is mounted on an insulated bedplate,
mounted on top of the car.
Requirements:
made of solid combustible material to reduce fire risk,
keeps dust out of shaft.
Sheet steel welded to steel frame provides a suitable door32 mm thk & door panel can be painted or faced with
aluminium or wood veneer.
should have robust steel angle frames to which top & bottom tracks may be fitted.
If a maintenance engineer unlocks the landing door a contact is broken which
switches off the electric supply & renders the lift inoperative.
1. Car doors fitted to lift car
2. Landing doors fitted to lift shaft
enclosure.
D i
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Doors may be of following types:
Two leaf side opening
Two lead centre opening
Single leaf side opening
Single hinged doors are suitable for residences & small houses they should be
self closing & provided with locking mechanism.
Door openings
>3-6 for simultaneous
loading/unloading
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TYPES OF LIFTS
Firemans Lift
mandatory for bldgs. Above 24m, out of reach of
fire brigade .
Should have direct access from street, separate
electric supply to that of other lifts. Special switch G.F on close to entrance
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Goods Lift
design similar to that of passenger lift, usually larger & car less decorative.
speed rarely exceeds 1m/s, accurate leveling is essential to facilitate loading &
unloading wheeled trolleys.
heavy goods require strong cars & efficient brakes, roping arrangements
designed to prevent slipping of rope.
Service Lifts designed & constructed to carry only goods.
floor area does not usually exceed 1 m2 & for small lifts to carry 50kg at speed
of 0.25m/s or 0.50m/s.
principles same as that of goods lift, but machine is much smaller & often
safety gear is not fitted.
used mainly by hotels & restaurants to provide service from kitchens to dining
area. car constructed of stainless steel which can be polished & easily cleaned.
A stainless steel removable shelf included, car opened at front or front & back.
doors to hatches can be hingedupward or sideway sliding or a roller shutter
may be provided.
Table: Common classification & speeds of goods lift
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Type of lift Speed (m/s) Load
(kg)
Document 0.4 10
ledger 0.4 35Food service 0.4 50
Small goods 0.25-0.5 100
Large goods 0.25-0.5 500-2000
Canteen
service
0.25-0.5 110-150
Hospital Bed Lift accurate floor leveling essential to allow bed to be wheeled into & out of the car.
car large enough to take a bed with room to spare for passengers.
speed between 0.25-1m/s.
min depth of car 2.4m, width 1.4m, height 2.2 m.
Hand powered lifts load above 25 kg, no. of operations per day are limited & maximum load for car
should be 100 kg.
hatch doors hinged timber or multi leaf metal sliding types.
method of operation is by endless hauling rope external to landing doors.
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Types
Elevators traction
gearlessmedium-high speedpassenger
geared low speed passenger hydraulic
plunger
hole-less
roped
Oil hydraulic lifts
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operated by water by high pressure water main with centralized pumping station,capital costs are high. modern lift uses oil pressure from self contained power plant driven by an electricmotor.
suitable with moderate car speed short travels are acceptable. suitable for goods lift, hospital lift or old age homes. speed ranges from 0.12-1 m/s & maximum travel is 21m. machine room is on lowest lvl. Served, can be remote from lift shaft. all lift loads carried by ram directly to ground thus simplifying the structural design ofthe shaft.
construction of shaft is cheaper & design is decided by degree of fire resistance reqd. simplicity of operation reduces maintenance cost & power pack can be sited belowstaircase, thus saving space.
Advantages power pack is at lower lvl. doesnot require machine room. machine rm. Relatively smaller, can be located at some distance from the shaft.
load imposed on lift shaft is far less than with elec. Traction lift thus costing less. no brake or winding mechanism, ropes, pulleys, driving sheave necessary. no counterweight & larger lift car can sometimes be used.Extremely accurate floor leveling can be achieved. acceleration & travel is very smooth.
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Hydraulic Elevator
Components
Machine room
7-9 minimum clear
Bottom of Beam (OH) 12-0 123
Pit (P)/Plunger
4-0
Travel +2-6
S: p. 1402, F.31.6
El t A li ti
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Elevator Applications:
Hydraulic TypesCommon to all: 2 to 5 floors; max rise 40 to 45 feet
Direct Plunger Holeless Roped Hydro
Telescoping HolelessLimited to 15-0 Expensive to Install
Limited to 40-0;
Problematic
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Operation
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Downward direction
Controlled by lowering valve A, which controls oil
returning to oil tank.
Lowering solenoid energized by an electric current& opens to allow oil to bypass lowering piston
B.Reduction in oil pressure behind piston allows
lowering valve to open.
Oil forced in oil tank & lift car moves downward.
Upward direction
Controlled by up valve C, which controls oil
returning to oil tank. For lift to travel up UP
solenoid valve is energized by an electric
current & opens to allow oil to enter above the
UP piston D. Since area of Up piston D is larger,oil pressure closes the valve & allows high
pressure oil to flow to ram & lift the car. The
spring loaded check valve E prevents oil from
flowing back along pipe F.
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Elevator Applications: Machine Room Less
Traditional Machine Room Less
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Paternosters
series of two persons doorless lift cars,suspended from hoisting chains which run over
sprocket wheels at top & bottom of the shaft.Provides up & down movement of passengers in
one shaft & when car reaches limit of travel in one
direction moves across to another set of chains &
engages with the guides to travel in other
direction. passenger enters & leaves moving car therefore
speed not to exceed 0.4 m/s.
installation used in universities, colleges etc.
were users are agile to use the lift.
Supports for cars at the top & therefore carsremain vertical at all times.
@ 650 passengers per hour can be carried.
safety devices provided to reduce accidents.
Constr ction
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Construction
RCC wall or 225 mm brickwall is required.
Shaft measures @ 2.6 m x
1.6 m, contains two set of
chains & guides.
A motor room is reqd. at top
of the shaft in which motor,
gearbox & sprocket wheels
are mounted. pit below is 4.5m-5.8m in
depth
Advantages
absence of controlgears reduces
maintenance cost.
reduction in waiting
time. Information by Architect
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1. No. of lifts-size & position
2. Particular of lift well
3. Size, position, No. & type of landing doors
4. No. of floors served
5. Height between floors
6. No. of entrances to car
7. total head room (in consultation with
manufacturer)
8. Access to machine room
9. Ventilation to machine room
10. Height of machine room
11. Depth of lift pit
12. Position of machine room
13. Supporting steel work at roof level.
14. Size & position of footing, close to pit
15. Passenger lift to carry household goods eg.
Refrigerator.
Planning & Working aspects
Data given in Architects data booke & NBC, dimension vary from manufacturer to
manufacturer- refer catalogue.
Staircase & shaft closer-one more flight upwards leads to machine room.
Information regarding depth of footings-deeper than pit depth.
Co-ordination between architect & different agencies.
Lift controls
Quantitative (Handling capacity) & qualitative (waiting time for passenger)
Example Problem
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Example Problem
Design an elevator system for a 10 story, single purpose tenant, office
building that provides an good level of service.
Construction level is normalFloor height: 12-0 floor to floor
Floor area: 15,000 net square feet (nsf) each
1. Determine Percent Handling Capacity (PHC)
Office buildingInvestment
range 11.5-13 %
say 12%
PHC=0.12
2 Determine Interval (I)
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2. Determine Interval (I)
Office building
Good service
I=25-29 sec
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3. Determine Building Population
Office building
Single tenant
Normal construction
range 90-110 sf/person
say 100 sf/person
Pop= 9 floors@15,000 nsf
100sf/personPop=1350 people
S: p. 1423, T.31.7
4. Determine Handling Capacity (HC)
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g p y ( )
PHC=0.12
HC=0.12 x 1350 people
HC= 162 people
5 Determine Rise & Select Car
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5. Determine Rise & Select Car
9 floors (above lobby)
12-0 floor-floor
Rise=9 x 12-0
Rise=108
Select Car:
2500# car
@400 fpm
S: p. 1432, T.31.9
6. Determine Average
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6. Determine Average
Trip Time (AVTRP)
12-0 floor-floor
2500# car400 fpm
9 floors
AVTRP= 64 secS: p. 1425, F.31.21
7. Determine Round
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Trip Time (RT)12-0 floor-floor
2500# car
9 floors
400 fpm
RT= 112 sec
S: p. 1428, F.31.23
9. Determine 5-minuteHandling Capacity (h)
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Handling Capacity (h)
h=300p/RT
h= 300 x 13/112
h= 34.8 people
.(p)
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2500# car
p= 13 people
S: p. 1422, T.31.5
. e erm ne num er o cars(N)
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(N)
N=HC/h
N= 162/34.8
N= 4.7 cars
say 5 cars
11. Confirm Interval (I)
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11. Confirm Interval (I)
I=RT/N
I= 112/5
I= 22.4 sec
Required I 25-29 sec
Design exceeds performancerequirements
11 (Re)Confirm Interval (I)
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11. (Re)Confirm Interval (I)
I=RT/N
I= 112/4
I= 28 sec
Required I 25-29 sec
Design meets performance requirements
12. Repeat Until
Performance Complies
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Performance Complies
Performance is in compliance
Use 4 cars (2500 lbs., 400 fpm)
Lobby Sizing
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Lobby Sizing
Size based on peak interval
15 or 20 minute peak time
5 sf/person
From previous example using 15 minute peak
h=34.8 people/5-min.104.4 people/15 min.Area= 104.4 people x 5 sf/person = 522 sf
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Codes and Standards
ANSI/ASME Code A17.1
NFPA 101 Life Safety Code
NFPA 70 Electrical
ANSI A117.1 Barrier Free
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