Properly Designing a Boiler Exhaust System
Post on 19-Jul-2016
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P l D i i Properly Designing A Boiler Exhaust SystemA Boiler Exhaust System
Common Problems Of Improperly Designed Boiler Exhaust Systems
Common Problems
Boiler Inefficiency
Flame Ignition Failure
Downtime
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Common Problems
Excess draft in the stack
Insufficient draft in the stack
FactorsFactors Improper breeching sizing
Improper stack sizing
Poorly designed ventilation systemPoorly designed ventilation system
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Important Criteria InStack System Design
Boiler Categorization
Stack Types
Stack Sizing
UL C tifi tiUL Certification
Materials Of Construction
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Boiler Categorization
Boilers are divided into four categories based on thepressure and temperature produced in the exhaust stackand the likelihood of condensate production in the ventand the likelihood of condensate production in the vent.
TIV
E
CATEGORY IICATEGORY I
NE
GAT CATEGORY II
APPLIANCECATEGORY IAPPLIANCE
VE
NON-CONDENSING CONDENSINGP
OS
ITIV CATEGORY IV
APPLIANCECATEGORY IIIAPPLIANCE
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Boiler Categorization
Category IA b il hi h i h i i
Category IIA b il hi h i h i iA boiler which operates with a non-positive
vent static pressure and with a vent gas temperature that avoids excessive condensate production in the vent.
(B V t T A)
A boiler which operates with a non-positive vent static pressure and with a vent gas temperature that may cause excessive
condensate production in the vent.(T BH)(B-Vent, Type A) (Type BH)
Category IIIA boiler which operates with a positive vent
Category IVA boiler which operates with a positive vent p p
pressure and with a vent gas temperature that avoids excessive condensate
production in the vent.(Type BH)
p ppressure and with a vent gas temperature
that may cause excessive condensate production in the vent.
(Type BH)( yp ) ( yp )
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Boiler Categorization
N C d i B ilNear-Condensing Boilers
Condensing BoilersCondensing Boilers
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Stack Types
Type B Gas Vents
•• Gas Appliance with Draft HoodGas Appliance with Draft Hood•• Gas Appliance with Draft HoodGas Appliance with Draft Hood
•• MasonryMasonry ChimneysChimneys
Liners
Type BH Gas Vents
• Most Cat II, III and IV boilers• Most Cat II, III and IV boilers
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Stack Sizing
Appliance category Altitude
Draft Draft
Appliance category
Power input
Altitude
Flue gas velocity
calculation based on criteria
calculation based on criteria
Type of fuel Flow restriction: tees, elbows, wyes, dampers, reducers
c te asuch as:c te asuch as: Flue gas temperature
Stack and breeching
Seasons(summer vs. winter)
A dStack and breeching diameter, height, length And more…
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Stack Sizing
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UL Certification
UL 103 (USA) / ULC959 (CAN)
Building HeatingAppliance Chimney
I t d d f ith d li id id ti l t d b ildi• Intended for use with gas and liquid residential type and building heating appliances which vent flue gases at a temperature not exceeding 1000ºF under continuous operating conditions with a maximum rated positive pressure of 60 inches W.C., as specified in the Chimney Selection Chart of the National Fire Protection Association Standard No. 211
• Can be installed in an unenclosed installation or enclosed in a noncombustible chasenoncombustible chase
• Also complied with a temperature test at 1700ºF for 10 minutes
• 1400ºF Chimney: same as above, but for flue gases at a
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temperature not exceeding 1400ºF
UL Certification
UL 1738 (USA) / ULC S-636 (CAN)
Special Gas Vents
I t d d t b t d di tl t th fl tl t f th C t• Intended to be connected directly to the flue outlet of the Category II, III and IV gas burning appliances, as defined by the National Flue Gas Code, ANSI Z223.1/NFPA 54, where the maximum continuous flue gas temperature produced does not exceed 550ºF with a maximum rated positive pressure of 15 inches W.C.
• Can be installed in an unenclosed or an enclosed installation made of combustible materials
• Also complied with a temperature test at 1700ºF for 10 minutes
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UL Certification
UL 1777 (USA) / ULC S-635 (CAN)
I t d d t b i t ll d i hi d t t il
Chimney Liners
• Intended to be installed in masonry chimneys used to vent gas or oil fuel fired residential type and building heating appliances where the maximum continuous flue gas temperature produced does not exceed 570ºF
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UL Certification
UL 1978 (USA & CAN)
I t d d f i i t ll ti f th l f k d
Grease Duct For Restaurant Cooking Appliances
• Intended for use in installations for the removal of smoke and grease laden vapors in commercial and industrial applications
• They are appropriate for continuous operation at temperatures not exceeding 500ºFexceeding 500 F
• Were evaluated in accordance with the Standard for Removal of Smoke and Grease-Laden Vapors from Commercial Cooking Equipment, NFPA 96Equipment, NFPA 96
• Also complied with an abnormal temperature test at 2000ºF for 30 minutes
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UL Certification
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Materials Of Construction
Installation-Ready Exhaust Systems
Structural
• Stainless steel (304 / 316 / 301 / AL29 4C)( )• Aluminized steel• ABS / PVC / CPVC / POLYETHYLENE• Galvanized steel
Insulation
• Air• Mineral fiber• Ceramic fiber
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Materials Of Construction
Freestanding Stacks
Structural
• Carbon steel• Cor-Ten steel• Stainless steel• Other materials per customer specifications
Insulation
• Per customer specifications
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Other Considerations
Installation-Ready Exhaust Systems
Draft control systems Dampers
N tiBarometric draft controls
Modulating draft systems
Negative pressurein the building
Air inletModulating draft systems
Draft inducer fans
Air inlet
Clearances for the boiler
Draft hoods Masonry chimney
Maximum length of breeching or stack
Other Considerations
Freestanding Stacks
Duct works and breeching systems Platforms and ladders
Concrete pad and footing design
FAA aircraftwarning system
Seismic calculations
Special anchoring
Wind loads
Lightening protectionSpecial anchoring Lightening protection
Special steel structural design
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Other Considerations
Local codes and regulations Special support requirements
Chemical and ASME and CWBthermal conditions certified products
Corrosion effects UL certified products
Special paint requirementsNeeds for related products: economizer, SCR products,
silencer, other
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Cleaver-Brooks Product Offering
Installation-ReadyExhaust Systems
Freestanding Stacks
Special Gas Vents
Chimney Liners
Grease Duct Products
cleaverbrooks.com/exhaustsolutions
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References
• CSA B149.1-10: Natural Gas & Propane Installation Code – Applies to the installation of Natural Gas & Propane Appliances & Equipment- http://www.csa.ca/cm/ca/en/standards
• NFPA -http://www.nfpa.org/categoryList.asp?categoryID=124&URL=Codes%20&%20Standards
• 211: STANDARD FOR CHIMNEYS, FIREPLACES, VENTS, AND SOLID FUEL-BURNING
NFPA 54: NATIONAL FUEL GAS CODE• NFPA 54: NATIONAL FUEL GAS CODE
• UL- http://www.ul.com/global/eng/pages/?noredirect
• UL103: Factory built chimneys-
• UL1738: Vent or chimney connector dampers for oil fired appliances• UL1738: Vent or chimney connector dampers for oil-fired appliances
• UL1777: Chimney liners
• ANSI Z21.86: Vented gas-fired space heating appliances- http://www.ansi.org/
• ASME STS-1 – 2011: Steel Stacks- http://www.asme.org/kb/standards
• ASHRAE- http://www.ashrae.org/standards-research--technology/standards--guidelines
• Manufacturer’s Operations and Maintenance Manuals• Manufacturer s Operations and Maintenance Manuals
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Eric GravelSales Manager
egravel@cleaverbrooks.com(450) 625-6060
clea erbrooks com/e ha stsol tions25
cleaverbrooks.com/exhaustsolutions
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