abs-lifts.pptx

7/27/2019 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


two speed

0.25-1.25 3000 6000 0-40


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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abs-lifts.pptx

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