greenheck external supply plenum

7/28/2019 GREENHECK External Supply Plenum

1/4

External Supply Plenums

Introducing Make-Up Air to Exhaust Only Hoods

April

2005


2/4

Make-up air can be introduced through the hood with an integrated supply plenum or an external supply

plenum. The shaded region represents the volume of the hood. Increasing the volume by using an external

plenum allows more smoke and heat to be held in the hood until it can be exhausted. This is important over

cooking equipment that produces

a great deal of heat and smoke,

such as a char-broiler.

External supply plenums areusually less expensive than an

integrated supply type hood and

can be retrofitted to existing

exhaust only hood systems to

improve performance and

comfort.

Advantages of External Supply Plenums

Recommended use: To introduce untempered ormarginally tempered air (heated air during colder

months). Air is kept near hood to minimize mixing

with air in the space.

Located along the backside of the hood

Air is directed through perforated panels

behind and below cooking equipment. Will not

disturb pilot lights

Provides clearance to limited combustibles*

Functions as a backsplash panel

Made of 304 or 430 stainless steel

Use with canopy (Type I or II) or proximity

hoods (plenum heights vary according to hood

type)

Insulate plenum to eliminate condensation

Multiple sections may be used to fit any length

of hood

*NFPA 96 requires a minimum 3 inch clearance

between the hood and any defined limited

combustible. See NFPA 96 for a listing of limited

combustibles.

Back Supply Plenum to be mounted 31.25 inches

above the finished floor.

145 cfm/ft.

145 cfm/ft.

Integrated Face Supply Exhaust Only with ASP

In order for a kitchen system to work properly, 100% of the exhausted air must be made up. Be sure to follow

the recommended supply rates for each type of external supply plenum. Maximum supply rates are only to be

used under ideal conditions and may cause performance and comfort problems. Be aware that in some cases,not all of the necessary make-up air can be brought through external supply plenums. Air may need to be

brought in from another source to completely balance the building. Transfer air from another room, or using

non-directional ceiling diffusers along with an external plenum, may be necessary for optimum performance. For

a complete explanation, see the Supply and Make-up air section (pg 15) of the Application and Design Guide

available for download at www.greenheck.com.

All Greenheck External Supply Plenums come with a variety of configurations and sizes of duct collars, either

mounted at the factory or shipped loose to be installed in the field.

Back Supply Plenum (BSP)

Design Considerations for External Supply Plenums

Back Supply Plenum with a

canopy type hoodBack Supply Plenum with a

proximity type hood


3/4

Recommended use: To minimize mixing with air in the

space by distributing airflow at the hood. May use

tempered or untempered air.

A series of perforated panels evenly distribute air at

lower discharge velocities which benefits hood capture

and containment

Made of 304 or 430 stainless steel to match hood Use with canopy (TypeI and II), or proximity hoods

(must mount high above hood against enclosure panels

or in ceiling grid when using proximity type hoods)

Multiple sections may be used to fit any length of hood

80-160

cfm/ft.

adjustable

damper

0-80 cfm/ft.

Air Curtain Supply Plenum (ASP)

Variable Supply Plenum (VSP)

160 cfm/ft.

180 cfm/ft.

> 110 cfm/ft.

110 cfm/ft.

Recommended use: To mix supply air with room air. May

use tempered or untempered air depending on climate.

Air is directed down onto cooking personnel through

the curtain and distributed out into the kitchen through

the face

Perforated panels evenly distribute air at low discharge

velocities

Made of 304 or 430 stainless steel

Use with canopy (Type I or II), or proximity hoods

Multiple sections may be used to fit any length of hood

Adjustable damper controls airflow between the curtain

and face: Face Supply 50-100%

Air Curtain Supply 0-50%

Variable Supply Plenum to be mounted 6 inches above the

bottom edge of hood or higher (shown), if ceiling heights allow.

Do not put finished ceiling below front face.

180 cfm/ft.

14 inch wide ASP

14 inch wide ASP

Standard ASP mounted at the standard height

Increase airflow by raising the mounting height

Increase airflow with a wider plenum

For increasing airflow through an Air Curtain

Supply Plenum (ASP):

Use multiple plenums(description on backcover)

Raise the mounting height of the plenum

Use the 24 inch wide plenumProximity hood with 24 inch wide ASP mounted

above top of hood with enclosure panels

24 inch wide ASP


4/4

Greenheck warrants this equipment to be free from defects in material and workmanship for a period of one

year from the purchase date. Any units or parts which prove defective during the warranty period will be

replaced at our option when returned to our factory, transportation prepaid. Motors are warranted by the

motor manufacturer for a period of one year. Should motors furnished by Greenheck prove defective during

this period, they should be returned to the nearest authorized motor service station. Greenheck will not be

responsible for any removal or installation costs.

As a result of our commitment to continuous improvement, Greenheck reserves the right to change

specifications without notice.

P.O. Box 410 Schofield, WI 54476-0410 Phone (715) 359-6171 greenheck.comCopyright 2005 Greenheck Fan Corp

External Supply Plenum SN, Rev. 2,April 2005

Our Warranty

External SupplyPlenum Type

Weight(lbs/ft.)

Width(in.)

Height(in.)

Length persection (ft.)

Recommended

Supply Rate

Maximum

Supply Rate

Back - BSP 42.0* 6 Variable 3 to 16 Up to 100% or 145 cfm/ft Up to 100% or 250 cfm/ft

Air Curtain - ASP

(14 inch)9.5 14 10 3 to 16 Up to 30 % or 110 cfm/ft Up to 50% or 180 cfm/ft

Air Curtain - ASP

(24 inch)12.5 24 10 3 to 16 Up to 50% or 180 cfm/ft Up to 80% or 280 cfm/ft

Variable - VSP 16.0 12 18 3 to 16 Up to 70% or 0-80 cfm/ftcurtain, 80-160 cfm/ft faceUp to 90% or 0-137 cfm/ftcurtain, 138-275 cfm/ft face

* Back Supply Plenum Only

Weights are based on a 24 inch hood height and a hood hanging height of 78 inches. For every increase

of 6 inches in hood hanging height or an increase of hood height from 24 inches to 30 inches, add an

additional 2.2 lbs/ft. of weight to the plenum. If the hood hanging height is 84 inches and hood height is

30 inches, add 4.4 lbs/ft. to the plenum.

Isometric view of multiple

Air Curtain Supply Plenums

Multiple plenums can be used to

increase airflow into the kitchen

without exceeding supply rate

limitations. Performance and increased

comfort are benefits of using multiple

plenums. Wrap ASPs along all open

sides of a canopy hood or use two

different types of supply plenums such

as a Back Supply Plenum (BSP) with

an Air Curtain Supply Plenum (ASP) to

provide up to 100% make-up air to the

kitchen. Using multiple ASPs (shown)

can eliminate the need for enclosure

panels above the hood if the bottom of

the plenums are mounted flush with

the top of the hood (shown to right).

Weights, Dimensions, and Supply Rates

Multiple Plenums

greenheck external supply plenum

Documents