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Design

95

Engineering

Specifications

GENERAL

Provide

a

high

performance,

low

maintenance,

centrifugal

fan

with

backward

curved

wheel and

spun

radial

sideplate.

Air

performance

and sound

ratings

shall be based

on

tests

and

procedures

in

accordance

with

AMCA

Publication

210

and

AMCA

Publication

300.

Fans

must

be

manufactured

and

assembled

in

the

U.S.A.

Acceptable suppliers:

Chicago

Blower

Corporation.

PERFORMANCE

Performance

shall include

a

steep

pressure

curve

with

non-overloading

horsepower

characteristics. Peak mechanical

efficiency

shall be

no

less than

84%.

Wheel inlet

to

be

designed

to

ensure

smooth,

stable air

flow

across

the

fan's

entire

operating

range.

System

static

pressure

changes

of

30%

shall result

in

an

approximate

10%

volume

reduction.

HOUSING

Fan

housing

shall

be

of

welded,

heavy

gauge

construction

with

seven common

discharge

positions.

Scroll

is

to

be

continuously

welded.

Plousing

stiffeners

and base

to

be welded construction

only.

Bolted

stiffeners

and construction

of

structural members is

strictly

prohibited.

All

welders shall

be

certified

to

AWS

code standards.

ROTOR

Wheel shall

be

welded

steel

construction.

Steel

wheel shall

have

cast

iron

hub

or

steel

hub that is

permanently

welded

or

fastened

to

heavy

gauge

backplate

using

Pluck lock

bolts and collars. Threaded

fasteners

are

not

allowed.

Steel

backward curved blades

must

be

single

sheet,

die

formed,

high strength

low

alloy,

or

equivalent

steel and

continuously

welded

to

backplate

and

wheel

sideplate.

All

welders shall

be

certified

to

AWS

code standards.

Wheels

to

be

statically

and

dynamically

balanced

to

G6.3

standards

in

accordance

with

ISO

1940

and

ANSI S2.19

specifications.

Shaft

shall be

turned,

ground,

and

polished

1045

SAE

cold rolled steel and

straightened

to

a

maximum

T.I.R.

of

0.002

inches.

Shafts

shall

be sized

so

the

fan

running

speed

is

30%

or more

below

the

first

critical

speed.

MOUNTING

Plousing

and base

assembly

complete

with

integral mounting

angles

or

structural steel

channel

for

connection

to

foundation.

For belt drive

fans,

the

adjustable

motor

base

to

be

welded

to

the

bearing

pedestal

or

steel channel base. For direct drive

fans,

an

integral

bearing

and

motor

pedestal

shall

be

welded

to

the

housing.

FACTORY MOUNTED

MOTORS

AND

COUPLING OR

DRIVES

(As Required)

Motors and

coupling

or

drives shall be

factory

mounted. Fan

to

be tested

at

running

speed

for

vibration and balance. Filtered vibration

readings,

taken

at

the

motor

bearings

and

fan

bearings,

not to

exceed

0.15

inches

per

second,

in

accordance

with

AMCA

Publication

204

“Balance

Quality

and

Vibration Levels

for

Fans.”

INLET

VOLUME CONTROL

(As Required)

Inlet volume control

(IVC)

device

shall

be

totally

enclosed

within

the inlet

cone.

IVC

device shall be

7-bladed,

and

pre-spin

the

incoming

air

to

control volume and

pressure.

Operation

of

IVC

shall be smooth without

fluttering

of

blades.

Performance

control shall

be

repeatable

and consistent without

slip

or

hunting

for

required

duty.

ACCESSORIES

Slip-fit

Inlet/Outlet

Punched,

Flanged

Inlet/Outlet

Type

B

or

C AMCA

Spark

Resistant

Construction

1-1/2”

NPT

Housing

Drain

Shaft Seal

Access Door

-

Quick

Clamp,

Flush

Bolted,

or

Insulated

Plug Type

Shaft Cooler

(Required

from

301

°F

and

above)

Inlet

Screen

Shaft

and

Bearing

Guard

-

painted

OSHA

yellow

Totally

Enclosed Belt

Guard

-

painted

OSHA

yellow

Adjustable

Motor Base

Extended

Grease

Fittings

Constant

or

Adjustable

Speed

V-Belt

Drives,

Min

1.3

S.F.

Flexible

Steel

Couplings

Bolt-on

or

Integral

Inlet Box

Mixing

Box

with

FGR

Port

AWS Code

Welding

Inlet

or

Outlet

Dampers

-

Parallel

or

Opposed

Bladed,

Manual

or

Automatic

Operation

Split

Housing

-

Horizontal

or

Wedge

Vibration

or

Unitary

Base

23