UNI-STACK™-1800 Series
Refractory-Lined Steel Ductwork

UNI-STACK-1800 refractory-lined, steel ductwork is designed to withstand high temperatures and resist corrosion from acid gases in chimney, breeching, and exhaust systems that vent boilers, furnaces, incinerators, fireplaces, appliances that burn wood or coal, kilns, kitchen appliances, diesel/gas engines, heat recovery systems, and process equipment. It can be used with all types of fuels and combustible materials. UNI-STACK-1800 ductwork can handle flue gas with a maximum temperature range of 960°F to 3,100°F for continuous firing and intermittent firing.

UNI-STACK 1800 series

Construction

UNI-STACK-1800 ductwork is available in eight refractory-lined models:
Model 1800
has a refractory aggregate bonded with calcium aluminate cement.
Model 1800
Plus
 replaces 1 inch of 1800 refractory with insulating board for thermal control in heat recovery applications.
Model 1800 V
 has a refractory of high-density aggregate bonded with high-purity calcium aluminate cement.
Model 1800
AR-2
 has a refractory of high-density aggregate co-bonded with high-purity calcium aluminate cement and potassium silicate binders.
Model 1800
AR-H
 has a refractory that is a low-shrink mix of 60 percent alumina to provide high strength, high density, and high abrasion resistance.
Model 1800
AR-T
 has an amorphous, vitreous silica refractory to provide high density and high abrasion resistance.
Model 1800
BB
 has foamed, closed-cell borosilicate blocks secured to the outer shell with 1/8-inch urethane asphalt adhesive membrane.
Model 1800
EE
 uses 1 inch of the standard Model 1800 refractory for engine exhaust applications.
Model 1800
CUS
 can be supplied with custom refractory and membrane linings to meet your needs.

UNI-STACK-1800 duct is constructed with a welded (or riveted for 26 gauge) longitudinal seam in standard lengths of 36 inches for inside diameters of 4 through 8 inches, and lengths of 48 inches (72 inches for heavy gauges) for inside diameters of 9 through 60 inches. Standard diameters are 4 to 60 inches inside diameter (Model 1800 Plus is 4 to 60 inches and Model 1800 BB is 30 inches or greater). Standard outer shell materials are 26-gauge aluminized steel or 11-gauge galvanized steel. Stainless steel (304 and 316) jackets are available. Model 1800 is not available in 26 gauge for inside diameters greater than 36 inches. Components are joined with a leak-proof and acid-resistant sealant. An 8-inch-wide, 26-gauge aluminized steel draw band is placed over each sealed joint and bolted tightly to secure the joint. For heavy-gauge outer shells, an 11-gauge galvanized steel draw band is available. Joints can also be welded to increase strength.

Clearance Requirements

For noncombustible materials, a clearance of 2 inches is required for inside diameters of 4 to 18 inches, and a clearance of 4 inches is required for inside diameters greater than 18 inches. Note: clearances in a noncombustible interior chase shall be as necessary to ease installation and/or allow access.

The following clearances must be maintained between Model 1800 and combustible building materials (a clearance of 6 inches is required for all diameters when used with low-heat appliances producing flue gas temperatures of 1,000°F or less).

Inside Diameter
(inches)
Clearance
(inches)

4-15

16

18-21

18

24

20

27

21

30-36

22

39-42

25

45

26

48

27

51

28
54
29

57

30

60

31

Application References and Listings: UL (Model 1800 only), BOCA, NFPA, SBC, UBC, NBC, ICBO
SilverGuard Antimicrobial
 

 
McGill AirFlow's UNI-STACK™ Duct Systems:

UNI-STACK-S Duct
UNI-STACK-1400 Series
UNI-STACK-1800 Series
UNI-STACK-ENG Chimneys
Applications

  

 

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An enterprise of United McGill Corporation—Family owned and operated since 1951

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