Ductwork connected to fume hoods may be arranged in a variety of patterns depending on requirements. Generally, the best exhaust system involves the shortest duct length and the fewest elbows. Duct size, length, and number of elbows affect static pressure loss and blower efficiency. Ideally, each fume hood should have its own ducting and blower to maximize hood flexibility and reduce danger of backdraft from other hoods.

Common or manifold ductwork designs can be used, provided duct and blower have been sized properly. In these designs, individual hood dampers are recommended to balance the system. Hood users must be aware of how different hood exhaust fumes will react when mixed in the ductwork. Rigid PVC ductwork is recognized as an excellent fume hood exhaust duct material. The smooth interior surface reduces static pressure loss and chemical waste build up, and PVC is extremely resistant to a wide variety of reagents. For some applications flexible PVC lined duct provides adequate service and can significantly reduce installation costs. When planning exhaust ducting, duct size, length, number of bends, and exhaust material must be considered.

Consult HEMCO for Lab Ventilation Solutions

InLine HEPA / Carbon Filter Pak

Filter paks are used in laboratory exhaust and supply systems to remove hazardous fumes & particulate 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

Continuously monitors face velocity air flow of fume hood. Select and calibrate at desired fpm velocity set point. If the hood face velocity falls below set point, an audible alarm sounds and a visual red indicator light appears. Air flow alarm is factory installed or can be field installed. 115V/60Hz AC.

Cat. No. 51403

Continuously monitors face velocity air flow of fume hood. Select and calibrate at desired fpm velocity set point. If the hood face velocity falls below set point, an audible alarm sounds and a visual red indicator light appears. Air flow alarm is factory installed or can be field installed. 115V/60Hz AC.

Cat. No. 51406

InLine HEPA / Carbon Filter Pak

Filter paks are used in laboratory exhaust and supply systems to remove hazardous fumes & particulate 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

Continuously monitors face velocity air flow of fume hood. Select and calibrate at desired fpm velocity set point. If the hood face velocity falls below set point, an audible alarm sounds and a visual red indicator light appears. Air flow alarm is factory installed or can be field installed. 115V/60Hz AC.

Cat. No. 51403

Continuously monitors face velocity air flow of fume hood. Select and calibrate at desired fpm velocity set point. If the hood face velocity falls below set point, an audible alarm sounds and a visual red indicator light appears. Air flow alarm is factory installed or can be field installed. 115V/60Hz AC.

Cat. No. 51406

Fume Hood Ductwork & Venting Accessories

Ducting and accessories are chemical resistant and easy to install.

Flexible and Rigid PVC Ducting	4”	4"	6”	8”	10”	12”	14”
	1. Flexible Ducting neoprene impregnated fiberglass reinforced with steel helix wire. Standard 12’ lengths. Each piece includes 2 clamps	Cat. No. 80051	Cat. No. 80052	Cat. No. 80053	Cat. No. 80054	Cat. No. 80055	Cat. No. 80056
	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. 82012	Cat. No. 82013
	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
	4. PVC 90° 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
	5. PVC 45° Elbow used in order to offset obstacles. Less static pressure loss than a 90o 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
	6. PVC 45° 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
	7. PVC Tee used in manifold exhaust systems. Has belled ends for duct connections.	Cat. No. 82034	Cat. No. 82036	Cat. No. 82038	Cat. No. 82040	Cat. No. 82044	Cat. No. 82046
	8. PVC Butterfly Damper modifies cfm for single or multiple hood arrangement. Has belled ends for duct connections.	Cat. No. 82450	Cat. No. 82452	Cat. No. 82454	Cat. No. 82456	Cat. No. 82458	Cat. No. 82460
	9. PVC Blast Gate Damper a gate that slides in and out to control cfm. Has belled ends for duct connections.	Cat. No. 82369	Cat. No. 82371	Cat. No. 82373	Cat. No. 82375	Cat. No. 82377	Cat. No. 82379
	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
	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
	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
	13. Round to Round Transition to smaller duct diameter.	Cat. No. 826134”- 6”	Cat. No. 826156”- 8”	Cat. No. 826178”- 10”	Cat. No. 8261910”- 12”	Cat. No. 8262012”- 14”	Cat. No. 8262114”- 16”