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iso ul New UL UniFlow Fume Hoods
Fume Hood Ventilation Solutions
direct drive blowers   belt drive blower   ductwork   centerfugal fan
Direct Drive Blowers   Belt Drive Blowers   Ductwork   Centrifugal Fans
Direct drive steel blower and impeller wheel are epoxy coated for chemical resistance.   Belt Drive steel blower and impeller wheel are epoxy coated for superior chemical resistance.   Each Fume hood shoud have its own ducting and blower to maximize hood flexibility   Self contained high plume exhaust system designed to remove hazardous fumes
filters   scrubber   scrubber   ventilation
Inline HEPA/Carbon Filters   Manifold Fume Scrubbers   In-Line Fume Hood Scrubbers   Ventilation Systems
Filter packs used to remove chemical odors and vapors from the airstream.   Manifold Fume scrubbers provide air pollution control for water soluable fumes and odors.

  For Laboratories requiring removal of acid vapors from exhaust , under corrosive conditions   Integrated components, blowers, fume scrubbers, and ducting
Fume Hood Ventilation
Lab Ventilation
Fume Hood Blowers / Belt Drive btt
A complete line of belt and direct drive exhaust blowers that are chemical resistant and available in standard and explosion-proof models. HEMCO blowers are designed to operate effectively and efficiently to remove noxious and hazardous fumes. Standard 115V 60Hz & International Electrical Configuration of 220V 50Hz AC available.
Epoxy Coated Steel Blower Belt Drive
Epoxy Coated Steel Blower
Blower
  Standard (STD) belt drive steel blower and impeller wheel are epoxy coated for superior chemical resistance. Explosion-proof blowers (EXP) have epoxy coated, non-sparking aluminum impeller wheel. V-belt drive and adjustable pulleys permit field balancing. Seven discharge positions to suit installation. Weather housing is furnished. Motor has thermal overload protection. Specify: 115 V single phase, 230 V single phase, 230/460 V three phase or 208 V (consult factory). 1 year manufacturer’s warranty
 
Catalog Number and Static Pressure
cfm A
Inlet
Diameter
B
Outlet
Size
1/2” Static Pressure 3/4” Static Pressure 1” Static Pressure 1 1/2” Static
Pressure
HP STD EXP HP STD EXP HP STD EXP HP STD EXP
296 8 7/8” 10 1/8” x 4 1/8” 1/4 51701 51801 1/4 51702 51802 1/4 51703 51803 1/4 51704 51804
474 8 7/8” 10 1/8” x 4 1/8” 1/4 51705 51805 1/4 51706 51806 1/4 51707 51807 1/2 51708 51808
652 8 7/8” 10 1/8” x 6 3/8” 1/2 51709 51809 1/2 51710 51810 1/2 51711 51811 1/2 51712 51812
800 8 7/8” 10 1/8” x 6 3/8” 1/2 51713 51813 1/2 51714 51814 1/2 51715 51815 3/4 51716 51816
914 9 7/8” 11 1/2” x 8 1/4” 1/2 51717 51817 1/2 51718 51818 -- -- -- -- -- --
1044 9 7/8” 11 1/2” x 8 1/4” 1/2 51719 51819 1/2 51720 51820 3/4 51721 51821 -- -- --
1175 9 7/8” 11 1/2” x 8 1/4” 1/2 51722 51822 1/2 51723 51823 3/4 51724 51824 -- -- --
1240 9 7/8” 11 1/2” x 8 1/4” 1/2 51725 51825 1/2 51726 51826 3/4 51727 51827 3/4 51728 51828
1240 11 7/8” 13 3/8” x 8 1/4” 1/3 51729 51829 1/2 51730 51830 -- -- -- -- -- --
1506 11 7/8” 13 3/8” x 8 1/4” 1/2 51731 51831 1/2 51732 51832 3/4 51733 51833 -- --  
1771 11 7/8” 13 3/8” x 8 1/4” 1/2 51734 51834 3/4 51735 51835 3/4 51736 51836 1 51737 51837
Polypropylene Belt Drive Blowers
Polypropolene Blower
Polypropolene Blower
 

High efficiency impellers produce low power consumption, reduced operating costs and quiet operation. 20 forward curved blades, in fire retardant polypropylene. Non-static and oil resistant v-Belt, cast iron pulleys, adjustable pulleys available, adjustment for tensioning and belt replacement. 230V explosion proof, non sparking, chemical resistant for hostile or hazardous environments. 115V single phase or three phase. Non-static and oil resistant v-belt, cast iron pulleys, adjustable pulleys available, adjustment for tensioning and belt replacement.
1 year manufacturer’s warranty

 
Catalog Number and Static Pressure
cfm A
Inlet
Diameter
B
Outlet
Diameter
0.5” Static Pressure HP 0.75” Static Pressure HP 1.0” Static Pressure HP
HP STD EXP HP STD EXP HP STD EXP
400 6” 6” 1/4 51450 51850 1/4 51460 51860 1/4 51470 51870
800 8” 8” 1/4 51451 51851 1/3 51461 51861 1/3 51471 51871
1000 8” 8” 1/2 51452 51852 1/2 51462 51862 1/2 51472 51872
1200 10” 10” 1/2 51453 51853 1/2 51463 51863 1/2 51473 51873
1600 10” 10” 1 51754 51854 1 51464 51864 1 51474 51874
Fume Hood Blowers / Direct Drive btt
Epoxy Coated Steel Blower Direct Drive
Direct Drive Blower
Direct Drive Blower
Direct drive steel blower and impeller wheel are epoxy coated for superior chemical resistance. Explosion proof blowers have epoxy coated non-sparking aluminum impeller wheels. Motor is 115V, 1 phase and has thermal overload protection. 1 year manufacturer’s warranty
 
A
Inlet
Diameter
B
Outlet
Size
HP STD EXP 1/4” SP 1/2” SP 3/4” SP 1” SP
cfm cfm cfm cfm
6” 7” X 4-3/8” 1/6 51177 51178 565 515 440 300
8” 8-3/4” X 5-7/16” 1/3 51179 51180 935 875 800 712
9” 10-1/8” X 4-1/8” 1/2 51181 51182 1050 980 920 850
9” 10-1/8” X 5-1/8” 3/4 51183 51184 1260 1220 1180 1100
Standard motors are 115V, 60Hz / 1 phase. Explosion proof motors are 115/230V, 60Hz, 1 phase. Other voltage, hertz, and phase motors are available.
 
Perchloric Acid Exhaust Blowers

Constructed of halar-coated steal & feature v-belt adjustable sheave drive, TEFC motor, nonsparking wheel, wash down nozzle, drain outlet, inlet & outlet flanges, & weather cover. Note: Blowers below are sized for 100 FPM.

Fume Hood Face Velocity cfm

Sash in full open position should be for setup of apparatus & maintenance service only. If opening is at 1/2 open at 120 fpm (feet per minute), face velocity at full open would be approximately 60 fpm.

The recommended face velocity for perchloric acid fume hood efficiency & safety should be 120 fpm. Lower face velocity may compromise user safety.

Perchloric Acid Hoods  
 
Perchloric Acid Sash Management & Design
Size Hood 48" 60" 72"
Full open cfm Exhaust Blower 950 1250 1525
1/2 open cfm Exhaust Blower 475 625 765
Perchloric Acid Exhaust Blowers

Blowers are constructed of fluoropolymer coated steel, are belt driven, include TEFC motors and feature a
spray wash nozzle and drain in theblower housing. The specifications to
the right are based on 120 Fpm face velocity.

(For 48” hoods) 475 cfm @ 1/2 open

52395

 

 

(For 48” hoods) 950 cfm @ full open

51395

 

 

(For 60” hoods) 625 cfm @ 1/2 open

 

52396

 

(For 60” hoods)1250 cfm @ full open

 

51396

 

(For 72” hoods) 765 cfm @ 1/2 open

 

 

52397

(For 72” hoods) 1525 cfm @ full open

 

 

51397

   
Fume Hoods Ductwork and Venting Accessories btt
Ducting and accessories are chemical resistant and easy to install
Flexible and Rigid PVC Ducting 4” 6” 8” 10” 12” 14”
Flexable Ducting

1. Flexible Ducting Neoprene impregnated fiberglass reinforced with steel helix wire. Standard 12’ lengths. Each piece includes two strap clamps.

Cat. No.
80051

Cat. No.
80052

Cat. No.
80053

Cat. No.
80054

Cat. No.
80055

Cat. No.
80056

Rigid Ducting

2. PVC Rigid Ducting chemical resistant for
permanent installations. Standard 10’ lengths
with straight ends.

Cat. No.
82004

Cat. No.
82006

Cat. No.
82009

Cat. No.
82011

Cat. No.
82013

Cat. No.
82015

PCD Coupling

3. PVC Coupling required to connect straight sections.

Cat. No.
82147

Cat. No.
82149

Cat. No.
82153

Cat. No.
82157

Cat. No.
82159

Cat. No.
82160

90 degree Elbow

4. PVC 90 degree Elbow used in order to offset obstacles. Has belled ends for duct connections.

Cat. No.
82060

Cat. No.
82061

Cat. No.
82063

Cat. No.
82066

Cat. No.
82068

Cat. No.
82069

45 degree elbow

5. PVC 45 degree Elbow used in order to offset obstacles. Less static pressure loss than a 90 degree elbow. Has belled ends for duct connections.

Cat. No.
82082

Cat. No.
82083

Cat. No.
82085

Cat. No.
82087

Cat. No.
82089

Cat. No.
82090

45 degree wye

6. PVC 45 degree WYE lateral for joining common ductwork in multiple hood designs. Branch diameter may be sized to 2” to 4” smaller than main diameter.Has belled ends for duct connections.

Cat. No.
82216

Cat. No.
82218

Cat. No.
82226

Cat. No.
82229

Cat. No.
82233

Cat. No.
82234

PVC Tee

7. PVC Tee used in manifold exhaust systems.
Has belled ends for duct connection.

Cat. No.
82034

Cat. No.
82036

Cat. No.
82038

Cat. No.
82040

Cat. No.
82044

Cat. No.
82046

PVC Butterfly

8. PVC Butterfly Damper modifies cfm for single
or multiple hood arrangement.
Has belled ends for duct connection.

Cat. No.
82450

Cat. No.
82452

Cat. No.
82454

Cat. No.
82456

Cat. No.
82458

Cat. No.
82460

PVC Blast gate

9. PVC Blast Gate Damper a gate that slides in and out to control cfm. Has belled ends for duct connection.

Cat. No.
82369

Cat. No.
82371

Cat. No.
82373

Cat. No.
82375

Cat. No.
82377

Cat. No.
82379

Rain Skirt

10. PVC Rain Skirt slips over straight pipe on roof to slope water away from cutout.

Cat. No.
82328

Cat. No.
82330

Cat. No.
82332

Cat. No.
82334

Cat. No.
82336

Cat. No.
82337

PVC Vent outlet

11. PVC Vent outlet for horizontal venting through wall or window. Angled end prevents rain from entering. Male connector included.

Cat. No.
80074

Cat. No.
80076

Cat. No.
80077

Cat. No.
80078

Cat. No.
80079

Cat. No.
80080

Weather Cap

12. Zero Pressure Weather Cap discharges fumes
vertically away from roof. Self-draining. Minimal static pressure loss. This is the recommended weather cap.

Cat. No.
82350

Cat. No.
82352

Cat. No.
82354

Cat. No.
82356

Cat. No.
82358

Cat. No.
82359

Condensation Ring Wash Ring Reducers
Condensation Ring Collects condensed vapors in ducting and channels them to a drain outlet.
10” Condensation Ring Cat. No. 82590
12” Condensation Ring Cat. No. 82591
Wash Ring Suited for use in perchloric acid duct systems. Features a wide angle spray nozzle and supply water connector.
10” Wash Ring Cat. No. 82580
12” Wash Ring Cat. No. 82581
PVC Reducer
Dia A
Dia B
Cat. No
6”
4”
82613
8”
6”
82615
10”
8”
82617
12”
10”
82619
Round to round transition to smaller duct diameter.
14”
12”
82620
16”
14”
82621
   
Clean Aire HEPA Filtration Systems btt

HEMCO Clean Aire HEPA Filter Paks effectively collect particulate contaminants from the exhaust air stream. HEPA filters are 99.999% effective at removing particulate .3 micron and larger. The filter pak housing features a hinged access door with gaskets and spring latches for convenient filter change. Inlet and outlet plenums with duct connection collars are installed. The HEPA Filter Pak can also be paired with a carbon filter pak to remove chemical fumes and odors.

Note: HEMCO recommends a minihelic or magnehelic gauge to monitor the airflow differential across the filter. The static pressure indicated would alert when to change filter. The gauges can be hood or filter mounted. We recommend ordering a back-up replacement filter.

Filter Pak
Clean Aire HEPA Filter Pak
CFM Size Duct Size Cat. No.
250-650 26” x 15” x 35 1/2” 4”, 6”,8” diameter 50188
650-1200 26” x 26” x 35 1/2” 8”, 10”, 12” diameter 50189
HEPA Filters Prefilter (6 per carton)
CFM Size Cat. No CFM Size Cat. No.
500 24” x 12” x 12” 50094 500 24” x 12” x 2” 52000
1000 24” x 24” x 12” 50095 1000 24” x 24” x 2” 52001
HEPA Filter Bag in bag out system

Filter Housing is fabricated of type-304 stainless steel & requires (1) carbon filter absorber, (1) 24” X 24” X 2” 30% pleated prefilter & (1) bag.

Bag-In bag-out filters are designed to meet air filtration requirements to handle hazardous fumes and vapors. The housing incorporates a ribbed bagging ring around the side access door over which a specially designed plastic bag is attached. Filters are then installed and changed through the bag to reduce the risk of exposure to personnel. Note: The carbon filter is not included with the housing. We also, recommend the sampling kit below to check if there has been a break through in the carbon filter, and ordering a back-up replacement filter.

Bag in bag out
Clean Aire HEPA Filter Bag-In Bag-Out System
Description CFM Size Cat. No.
Clean-Aire HEPA Filter Bag-In Bag-out System 1000 26” X 26” X 35-1/2” 51189
HEPA Filters 1000 24” X 24” X 12” 50095
HEPA Prefilter (6 per carton) 1000 24” X 24” X 2” 52001
Replacement Bags (2 per carton) 51989

Minihelic Gauge
Gauge monitors the pressure differential across the HEPA filter, Gauge conveniently mounts on the fume hood or on the filter housing. Measure range is from 0 to 2.0” wg Gauge is 3” dia. with 5% accuracy

Cat. # 51300

Magnahelic Gauge
Gauge measures static pressure across the HEPA filter. Can mount on the fume hood or the filter housing. Range of measurement is from 0 to 2” wg. Gauge is 5” dia with 2% accuracy.

Cat. # 51301

 
Clean Aire Carbon Filtration System

HEMCO carbon filter paks are used in laboratory exhaust and supply systems to remove chemical odors and vapors from the airstream. Filters are loaded with virgin coconut activated carbon to efficiently absorb organic solvents and acid fumes. The filter pak housing features a hinged access door with gaskets and spring latches for convenient filter changes. Inlet and outlet plenums with duct connection collars are installed. The carbon filter pak can also be paired with a HEPA filter pak to collect particulate contaminants. For other types of contaminates, please see the chart below.

Note: A standard “01” activated carbon filter for organics is included.HEMCO recommends the sampling kit to check if there has been a breakthrough in the carbon filter, and ordering a back-up replacement filter.

Filter Pak
Clean Aire Carbon Filter Pak
CFM Size Duct Size Cat. No.
250-650 26” x 15” x 35 1/2” 4”,8” diameter 50297
650-1200 26” x 26” x 35 1/2” 8”, 10”, 12” diameter 50298
Carbon Filters Prefilter (6 per carton)
CFM Size Cat. No CFM Size Cat. No.
500 24” x 12” x 12” 52100 500 24” x 12” x 2” 52000
1000 24” x 24” x 12” 52101 1000 24” x 24” x 2” 52001
Carbon Filter Bag in bag out system

Filter housing is fabricated of type-304 stainless steel & requires (1) carbon filter absorber, (1) 24” X 24” X 2” 30% pleated prefilter & (1) bag.

Bag-In bag-out filters are designed to meet air filtration requirements to handle hazardous fumes and vapors. The housing incorporates a ribbed bagging ring around the side access door over which a specially designed plastic bag is attached. Old filter is removed then new filters are then installed and changed through the bag to reduce the risk of exposure to personnel. Note: The carbon filter is not included with the housing. We also, recommend the sampling kit below to check if there has been a break through in the carbon filter, and ordering a back-up replacement filter.

Bag in bag out
Clean Aire Carbon Filter Bag-In Bag-Out System
Description CFM Size Cat. No.
Clean-Aire Carbon Filter Bag-In Bag-out System 1000 26” X 26” X 35-1/2” 51198
Carbon Filters 1000 24” X 24” X 12” 52101
Carbon Prefilter (6 per carton) 1000 24” X 24” X 2” 50001
Replacement Bags (2 per carton) 51999

Carbon Efficiency Chart

The following chart is a partial list of contaminants and the proper type of carbon for maximum efficiency. For additional contaminants, please consult factory. *Filter Check Available

Contaminant

Type

Contaminant

Type

Contaminant

Type

Contaminant

Type

Contaminant

Type

Acetic Acid

01

Chlorophicbin

01

Ethylene Dichloride

01

Iodine

01

Propyl Mercaptan

01

Acetone

01

Crotonaidehyde

01

Ethylene Oxide

06

Isopropyl Alcohol

01

Pyridne

01

Ammonia*

05

Cyclohexanone

01

Formaldehyde

03

Isopropyl Ether

01

Styrene Monomer

01

Benzene

01

Dibromoethane

01

Formic Acid*

02

Methyl Butyl Keytone

01

Sulphur Dioxide*

02

Butyl Acetate

01

Dichloronitroethane

01

Glutaraldehyde

04

Methyl Ethyl Keytone

01

Sulfuric Acid*

02

Caprylic Acid

01

Dichloropropane

01

Heptane

01

Methylene Chloride

01

Toluene

01

Carbolic Acid

01

Dimethyl Sulfate

01

Heptylene

01

Nitric Acid*

02

Trichloroethalene

01

Carbon Tetrachloride

01

Dipropyl Keyton

01

Hexane

01

Nitrobenzene

01

Trichloroethane

01

Chlorine*

02

Ethyl Alcohol

01

Hydrogen Bromide*

02

Nitropropane

01

Xylene

01

Chloroform

01

Ethyl Benzene

01

Hydrogen Chloride*

02

Octalene

01

     
HEMCO's Inline Fume & Vapor Scrubbers btt

Scrubber systems offer high efficiency and minimal maintenance on meeting pollution control requirements.

Remote recirculation Pump  

Remote Recirculation Pump

Can be supplied for installations where the scrubber is located outdoors and the possibility of freezing is present.

 

CFM

Cat. No

500

80210

1000

80211

2000

80212

4000

80213

6000

80214

8000

80215

  Scrubber

PH Control Package

Allows precise control over effluent quality and provides neutralization of contaminants. The PH control system consists of a weather tight, corrosion -proof enclosure containing an analyzer, pre-wired chemical feed pump, weather- protected terminal block, clear PVC face plate and external chemical -feed connection. Enclosure can be mounted on any vertical surface. A heavy-duty industrial probe with a 10” lead wire is supplied, along with (2) 10” lengths of vinyl tubing to connect the feed pump
Cat. No. 80112

PH Control
 

Fume Scrubbers provide excellent air pollution control for water soluble fumes and odors by moving contaminated air through a filter pack media exposing over forty square feet of surface per cubic foot. Containment is collected on filter media surface and rinsed off with water, excess water is then mechanically removed and cleaned air is released. When conditions require, chemical additives can increase absorptive capacity of the scrubber. Unit includes integral recirculation tank and pump which significantly reduces water consumption and related waste disposal costs. Fan is not included, must be sized to meet exhaust requirements. Request a Plan-A Scrubber specification sheet for planning your scrubber.

 

Catalog Number and Fume Removal Efficiencies
(based on a 3 foot bed)

Atmospheric Contaminant

5 Foot Bed Series

With pH Control Package

Acetic Acid Mist

NR

90-95%

Alcohols

*

*

Alkaline Mists, General

99.9%

99.9%

Aqua Regina Gas

95-98%

96-98%

Ammonia Gas

NR

98-99%

Chlorine

NR

95-98%

Chromic Acid

99%

99%

Cyanide Solutions

99.9%

99.9%

Fluoborate Mist

99%

99%

Formaldehyde

NR

98-99%

Haldid Mist

98%

98%

Hydrofloric Acid

96-99%

98-99%

Hydrogen Cyonide

NR

95-98%

Nickle Suffate

99%

99%

Nitrogen Dioxide

*

*

Perchloric Acid

85-90%

95-98%

Phosphoric Acid

85-90%

95-98%

Sodium Sulfide

99%

99%

Sulfamate Mist

99%

99%

Sulfuric Acid

99.9%

99.9%

Zinc Chloride

95%

95%

Horizontal Air Flow Scrubber

Scrubber

Blower

Size

Dimensions

Cat.No.

Size

Cat.No.

A

B

C

500 CFM

49”

30”

18”

80000

500 CFM

80010

1000 CFM

50”

34”

22”

80001

1000 CFM

80011

2000 CFM

50”

40”

28”

80002

2000 CFM

80012

3700 CFM

52”

49”

37”

80003

3700 CFM

80013

6000 CFM

53”

58”

45”

80004

6000 CFM

80014

8000 CFM

54”

65”

52”

80005

8000 CFM

80015

The above efficiencies are intended as a guide representing average values. Specific combinations and concentrations of fumes may result in a significant variation from the above. * Requires extended packing depth and chemical addition to scrubber solution.  
Inline Fume & Vapor Scrubbers btt

The Fume Hood Scrubber is designed for laboratories that require removal of acid vapors from exhausted air, under the most demanding corrosive environmental conditions. VS Scrubbers are compact vertical venturi units for indoor installations.

 
Vapor Scrubber

•Low operating cost

•Sizes from 8” to 20”, larger sizes available

•Highly effective for water soluble acids

•No moving parts to wear out or replace

•Installs directly into exiting duct systems

•Average installation time 2 hours with
minimal tools

•Uses no packing material to clog or replace

•Allows the isolation of individual hoods or
tanks that require pollution reduction

•Low water consumption at a minimum
8 gallons per hour

•Can be ducted if necessary to meet
venting requirements.

Scrubber

The design of the

Inline fume scrubber

is based on the need

for a simple, compact,

efficient, and

water conservative

apparatus for the

removal of particulates

and water soluble

vapors from individual

laboratory fume hoods.

Scrubber

Optimal Air Volume

240-250 CFM

580-720 CFM

890-1000 CFM

1590-1735 CFM

1950-2400 CFM

2400-3052 CFM

Overall Height “A”

38.75”

44.77”

50.75”

61.75”

73.537”

78.5”

Inlet Diameter “D”

8”

10”

12”

15”

18”

20”

 

Cat. No.

Cat. No.

Cat. No.

Cat. No.

Cat. No.

Cat. No.

PolyPro Construction

85008

85010

85012

85015

85016

85018

Recirculation System: includes recirculation tank, ph meters, recirculation pump, chemical feed tank and pump. Cat.No. 85000

 
Centrifugal Fans btt
Manifold

•Installed quickly and easily on reinforced
roof curb

• Designed to withstand up to 125 mph wind loads
with out guy wires

• Performance capacities range from 270 - 2400
cfm and up to 3.5 in. wg per fan

• Meets ANSI Z9.5 , NFPA 45 and ASHRAE
guidelines

• U.L. listed for electrical 705 power ventilators

• AMCA Certified for Sound and Air performance
AMCA 210 & 300

• Components are electrostatically powder coated
with a 2 part corrosion resistant coating, standard color: Gray

• Housing Style is an In-Line Configuration

• 1 Year Warranty

Centrfugal Fan'
 
Centrifugal Fan Centrifugal Fan

Housing Style

inLine Configuration

Stack Style

High Plume Nozzle

Minimum Flow

270 cfm

Maximum Flow

24,000 cfm

Maximum ESP

Up to 3.5 in wg (875 Pa)

UL Listed

U.L. for electrical 705 power
ventilators

AMCA
Certified

Sound and Air performance AMCA210 & 300

Warranty

1 year

Unit Size

Cat. No.

Dimensions
In Inches

Performance Range (cfm)

Nozzle Size Range

A

B

Min

Max

Min

Max

9 85009 21 5/8 21 5/8 270 1750 4 9
10 85010 21 5/8 21 5/8 450 1800 5 10
12 85012 21 5/8 21 5/8 600 2640 6 13
13 85013 23 5/8 23 5/8 810 3160 7 14
16 85016 27 5/8 27 5/8 -- 7080 8 18
 
     
Laboratory Ventilation Systems btt

Designed to offer the complete solution to laboratory ventilation concerns. Integrated components, blowers, fume scrubbers, and ducting are engineered together to provide a safe, effective, and efficient fume hood ventilation system. VAV controllers minimize the amount of conditioned air that is exhausted through the fume hood.

Lab Ventilation
Supplemental Room Air Supply

Laboratory supplemental air supply package is designed for situations where there is a shortage in availability of proper air supply to fume hoods. Supplemental air supply package serves as a alternative to auxiliary air hoods by diffusing make-up air to the laboratory rather than creating turbulence at the face of the hood. Package includes: 2’ x 2’ ceiling diffuser, prefilter, flexible ducting, and fan.

500 CFM Package 1 Diffuser Included Cat. No. 90001
1000 CFM Package 2 Diffusers Included Cat. No. 90002
1500 CFM Package 3 Diffusers Included Cat. No. 90003
Variable Air Volume Controls VAV

Variable Air Volume (VAV) Systems allow fume hoods to reduce energy consumption while maintaining face velocity. The system operates by sensing actual face velocity and actuating a motorized damper or blower speed control to continuously adjust face velocity as sash is raised or lowered.

VAV Damper Control

Utilizes electronically actuated dampers within the ductwork to create and maintain optimal air flow. The VAV System includes the front mounted audio-visual alarm, electronic actuated damper controller and wall-mounted sensor, transformer, and calibration. Night set back, emergency airflow, mute of audible alarm, and self-test mode are standard features of the unit. Cat. No. 51401

 
Laboratory Ventilation Recommendations

Proper placement and use of fume hoods and blowers are important laboratory ventilation requirements. HEMCO offers the following suggestions to help in your laboratory layout. Please feel free to contact HEMCO’s technical support team in order help with your laboratory needs.

Location of Hood

Room airflow patterns and user convenience are the most important considerations in planning the location of hoods within the laboratory.
Hoods placed directly in front of doors, open windows, or air conditioning registers will not perform efficiently. The drafts interfere with the airflow into the fume hood.
Hoods should not be placed where users would be forced to work in the line of traffic. Traffic in front of the hood adversely affects fume hood airflow
When common exhaust or supply systems are used for several hoods, the hood units should be arranged so minimum amount of ductwork is required.
Hoods used as part of an air conditioning system to exhaust air from the laboratory should generally be located on the opposite wall from the side-wall inlet registers. The hoods should be placed so that air from the registers or diffusers sweep through the laboratory area first then into the hoods.

  Hood Location
Hood Operation  

Proper use and maintenance will increase hood life.
Hoods should not be used as laboratory storage space. Piles of unnecessary material or unused bottles and flasks can block exhaust openings and interfere with hood performance.
An airflow monitor should be incorporated on the hood to monitor velocities and warn operator of potentially dangerous low air flows through the hood due to damper or blower failure, blockage of ductwork system, or extreme sash opening height.

 
Typical Ventilation Installations
Vnet Installations
Blower Selection and Installation

Blower systems must be properly installed and maintained in order to properly control the amount of air movement through the hood.
Select a blower with a large enough capacity for your application and set-up. Allow for some drop in capacity from fouling by dust and other contaminants.
Blowers and ductwork should be arranged so that pressure loss in the system is minimal. Minimize the use of elbows and other restrictions. The simplest arrangements are the most effective and efficient.
It is suggested that each hood have its own blower and ducts for maximum flexibility and to avoid back flow from other hoods. Common ductwork systems will also perform efficiently, provided ducts and blowers have been properly sized for the number if hood units in the system.
It is recommended that the blowers be located as close as possible to the exhaust end of the duct system. By keeping the number of elbows to a minimum, the air will be under negative pressure; thereby, should a leak occur, clean air would be pulled into the duct rather that contaminated air being pushed out.
Auxiliary air hoods, supply, and exhaust blowers should be operated by one switch to avoid danger of turning on supply blower only. An alternative method would be to have one switch operate both exhaust and supply blowers and a second switch operate exhaust blower only.
Where fume hoods are used as part of the laboratory ventilation system, blowers should be in operation at all times.

Blower Maintenance

Proper maintenance of blower and ducting will increase the efficiency of your fume removal system.
Blower and ductwork systems should be part of your regular maintenance schedule. Contaminant build-up collected on impeller blades of a centrifugal blower can greatly reduce its capacity.
Blowers should be checked to make certain the direction of rotation is correct. Centrifugal blowers will function while rotating in wrong direction but output will be greatly reduced.
The above figures show various suggested arrangements of ducts and blowers. Blowers may be installed within the lab, on the roof, on an external wall, or in the fume hood itself. Your choice of arrangements will depend on your particular laboratory location and set-up, facility policies, and building codes.

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