EXHAUSTO: Venting Design
Appliance Categories
ASHRAE Equation & Chimney Pressures Common
Code Violations
Chimney Automation Systems
Combustion Air Supply
Boiler Room Simulator
Overdraft Damper System
Dryer Venting
Appliance Categories
• ANSI Venting Categorization
Sub Title
Appliance Categorization
Atmospheric
Draft Hood
Fan Assisted
Scotch Marine
Draft Diverter
I
Negative
Forced Draft
Sub
Title
Fan Assisted
(high
efficiency)
II
III
IV
Condensing
Positive
Acceptable Venting Material
Atmospheric
Fan Assisted
Forced Draft
B-Vent
B-Vent
UL103 P-Stack
Masonry
Masonry (interior)
Welded Steel
I
Negative
III
Sub
Title
Fan Assisted
(85+ efficiency)
AL29-4C double wall
Condensing
II
IV
(85 – 90 % efficiency)
(90+ efficiency)
AL29-4C double wall
AL29-4C single wall
Positive
CPVC (tested with appliance)
Masonry Chimney Liners
Reference: ANSI Z223.1-2002 10.4.1 and 13.1.9, NFPA211 4-2.2
•Atmospheric
Clay tile liner
•Fan Assisted
•Forced Draft
Clay tile liner (interior chimney)
Positive pressure steel liner
Ex. Welded steel,
Inner liner of pressure stack
Steel liner (exterior chimney)
Exception: Clay tile liner can be
used with exterior chimney if an
Atmospheric appliance is
connected to the same chimney
Negative
Sub Title
I
III
Positive
•Fan Assisted
II
IV
•Condensing
(85+ efficiency)
AL29-4C Liner
AL29-4C Liner
Chimney Design Equation
1996 Edition
INPUTS:
•
•
•
•
•
•
•
•
Appliance Type
Fuel Type
MBH Input
CO2% in Flue Gases
Flue Gas Temperature
Ambient Temperature
Altitude
Flue Layout
Theoretical
Draft (-)
Sub Title
RESULTS:
•
•
•
•
•
Flue Gas Volume
Flue Gas Velocity
Theoretical Draft
Total Pressure Losses
Appliance Outlet Pressure
Pressure
Losses (+)
+
Outlet
Pressure
Boiler Efficiency versus Draft
Sub Title
Annual Draft Variations
Sub Title
Chimney Draft – Steady-State
Sub Title
Draft Variations During Operation
Vent = 30’ vert./10’ horiz., 18” diam.
4 Fan-assisted Cat I boilers with
1,000 MBH input each
Constant ambient of 60°F
Sub Title
Draft requirement: 0.05”WC
Modulating Boiler Systems
Gravity Stack Design
Sub Title
Chimney Automation Systems
Sub Title
CASV – Chimney Automation System
Sub Title
CASI – Chimney Automation System
Sub Title
Modulating Boiler Systems
Controlled Draft Design
Sub Title
First Cost Analysis
Ordinary Stack Material Cost
EXHAUSTO System Material Cost
Item
Qty
Item
Qty
List Price
20" pressure stack
35'
$
5,775
12" pressure stack
50'
$
4,600
16" pressure stack
5'
$
630
12" Tee
1
$
345
14" pressure stack
5'
$
535
12" end cap
2
$
260
10" pressure stack
5'
$
405
12" x 8" reducing Tee
4
$
1,240
20" Tee
1
$
610
20 " end cap
1
$
205
Sub Title
20" x 16" tapered reducer
1
$
410
1
$
360
16" x 8" reducing Tee
1
$
355
16" x 14" tapered reducer
1
$
280
14" x 8" reducing Tee
1
$
335
14" x 10" tapered reducer
1
$
245
10" x 8" reducing Tee
1
$
295
10" end cap
1
$
130
20" stack cap
1
$
640
20" x 8" reducing Tee
Total
List Price
$ 11,210
Total
$ 6,445
National Fuel Gas Code
•
•
•
•
•
•
•
Horizontal distances
Large stack area
Self venting connector
rise
Fan Min capacities
Different type of
Sub Title
appliances
Existing masonry
chimneys
Location of draft
inducer
NFPA 54
IFGC
ANSI Z
223.1
Common Code Violations
Chimney
Automation System
Sub Title
(NFPA 54) Z223.1-2002 (Venting of Equipment)
10.6.1.4 The total horizontal distance of a vent plus the horizontal vent connector serving draft hood-equipped appliances
shall not be greater than 75 % of the vertical height of the vent.
Table 13.1 and 13.2 The total horizontal length of the vent plus the vent connector for a single Category I appliance is: 100%
of the height (vent 6 – 30 ft high); 30 ft (vent 31 – 50 ft high); 50% of the height (vent 51 – 100 ft high)
Common Code Violations
3" 4" 5" 6" 7" 8" 9" 10" 12" 14" 16" 18" 20" 22" 24"
4.5' 6' 7.5' 9' 10.5' 12' 13.5' 15' 18' 21' 24' 27' 30' 33' 36'
Chimney
Automation System
Sub Title
(NFPA 54) Z223.1-2002 13.2 (Sizing of Venting Systems)
13.2.2 The maximum vent connector horizontal length shall be 18 in./in of connector diameter.
13.2.4 The length of the common vent manifold shall not exceed 18 in./in. of common vent diameter.
13.2.5 The horizontal length of the common vent offset shall not exceed 18 in./in. of common vent diameter.
Common Code Violations
3" 4" 5" 6" 7" 8" 9" 10" 12" 14" 16"
7" 10" 12" 14" 18" 22" 22" 26" 30" 36" 42"
Chimney
Automation System
Sub Title
(NFPA 54) Z223.1-2002 13.2.17 (Sizing of Venting Systems)
13.2.17 Where two or more appliances are connected to a vertical vent or chimney, the flow area of the largest section of
vertical or chimney shall not exceed seven times the smallest listed appliance categorized vent areas, flue collar area, or draft
hood outlet area unless designed in accordance with approved engineering methods.
Common Code Violations
Chimney
Automation System
Sub Title
(NFPA 54) Z223.1-2002 10.10.4.2 (Venting of Equipment)
10.10.4.2 Vent connectors serving Category I appliances shall not be connected into any portion of mechanical
draft systems operating under positive static pressure, such as those serving Category III or Category IV appliances.
Side-wall Venting
Sub Title
Z223.1-51-2002 (Venting of Equipment)
10.3.4.6 Mechanical Draft Systems.
The exit terminals of mechanical draft systems shall be not less than
7ft above grade where located adjacent to public walkways.
Side-wall Venting
Sub Title
Z223.1-56 (Venting of Equipment)
7.8 Venting System Location.
(a) A Venting system shall terminate at least 3 ft (0.9 m) above any forced air
inlet located within 10 ft (3.1 m).
Exception No. 1: This provision shall not apply to the combustion air intake of a
direct-vent appliance.
Exception No. 2: This provision shall not apply to the separation of circulating
air inlet and flue gas discharge of listed outdoor appliances.
Side-wall Venting
Sub Title
Z223.1-56 (Venting of Equipment)
7.8 Venting System Location.
(b) The venting system of other than a direct-vent appliance shall terminate at
least 4 ft (1.2 m) below, 4 ft (1.2 m) horizontally from, or 1 ft (30 cm) above any
door, window, or gravity air inlet into any building. The bottom of the vent
terminal shall be located at least 12 in. (30 cm) above grade.
Roof-top Venting
Sub Title
Z223.1-56 (Venting of Equipment)
Gravity Stack Terminations
Sub Title
NFPA Fig. 12a
NFPA Fig. 12b
Gravity Stack Terminations
Experience Shows
Hypotenuse of
two obstruction
edges
Hypotenuse of
two obstruction
edges
2 ft above
hypotenuse
Sub Title
More than
10 ft
2 ft above
hypotenuse
Mechanical Draft Systems Defined
Z223.1-2002 Standard for Venting of Equipment
10.3.4.1 Mechanical draft systems shall be listed and shall be installed in accordance
with the terms of their listing and both the appliance and the mechanical draft system
manufacturer’s instructions.
10.3.4.2 Gas utilization equipment requiring venting shall be permitted to be vented by
Sub
Title draft systems of either forced or induced draft design.
means
of mechanical
Exception: Incinerators
10.3.4.5 Where a mechanical draft system is employed, provision shall be made to
prevent flow of gas to the main burners when the draft system is not performing so as to
satisfy the operating requirements of the equipment for safe performance
Mechanical Draft Systems Defined
IFGC - Section 503 (Venting of Equipment)
503.6.9.3 Mechanical draft. Chimney venting systems using mechanical
draft shall be sized in accordance with approved engineering methods.
Z223.1-2002 Standard for Venting of Equipment
Sub Title
10.5.3.1 Size of Chimneys. Chimney venting systems using mechanical
draft shall be sized in accordance with approved engineering methods.
CASV – Chimney Automation System
Sub Title
CASI – Chimney Automation System
Sub Title
RSIB – Power Venter
•
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•
•
Sub Title
•
•
•
•
•
•
SS16 construction
Removable access door
Direct drive
Class A insulated motor - eliminates the
need for secondary fan cooling
Maintenance free
575 ºF Continuous Duty
UL 378 – Draft Equipment
The RSIB fan can vent category I, II, III
and IV appliances with or without
barometric dampers
Simple design with few components
reduces the risk of failure and
simplifies service
RSIB is of Type B, Spark Resistant
Construction
Installation Options - RSIB
Sub Title
CASV Applications – Stack
Downsizing
Sub Title
Hazen High School – Renton,
WA
Soldier Field - Chicago, IL
CASV Applications - Aesthetics
Getty Center – Los Angeles,
CA
Sub Title
Rigel – South San
Francisco, CA
CASV Applications - Aesthetics
SBC Center – San Antonio, TX
Sub Title
CASV Applications
Sub Title
MODS
Modulating Overdraft Damper
System
Modulating Overdraft Damper System
Sub Title
MODS Components
•
Sub Title
MDF Damper

Sizes – 12 in. to 48 in. diameters

Multiple opposed blades made of 16
gauge type 316 stainless

Pressure stack flange connections

Rated to 700°F
EBC30

Prime function

Additional over-pressure protection for
Forced-draft boilers
MODS Applications
Kaiser Center - Oakland, CA
Wells Fargo - Great Falls, MT
Sub Title
Markham Road - Toronto
MCAS
Mechanical Combustion Air
Supply
Codes and Standards
Code Requirements – Air for Combustion and
Ventilation
• Z223.1-2002 8.3.3 Outdoor Combustion Air.
8.3.3.1 Two Permanent Openings Method. Two permanent
openings, one commencing within 12 in. of the top and one
commencing within 12 in. of the bottom of the enclosure,
shall be provided. The openings shall communicate directly,
or by ducts, with the outdoors or spaces that freely
communicate with the outdoors as follows:
Sub Title
(1)
Where directly communicating with the outdoors or through
vertical ducts, each opening shall have a minimum free area
of
1 in.²/4000 Btu of total input rating of all equipment in the
enclosure.
(2)
Where communicating with the outdoors through horizontal
ducts, each opening shall have a minimum free area of not
less than 1in.²/2000 Btu of total input rating of all equipment
in the enclosure
Codes and Standards
Code Requirements – Air for Combustion and
Ventilation
• Z223.1-2002 8.3.3 Outdoor Combustion Air.
8.3.3.2 One Permanent Opening Method: One permanent
opening, commencing within 12 in. of the top of the
enclosure, shall be provided. The opening shall directly
communicate with the outdoors or shall communicate
through a vertical or horizontal duct to the outdoors or
spaces that freely communicate with the outdoors and shall
have a minimum free area of the following:
Sub Title
(1)
(2)
1 in.²/3000 Btu of the total input rating of all equipment
located in the enclosure, and
Not less than the sum of the areas of all vent connectors in
the space.
Codes and Standards
Sizing of Gravity Louvers
Louver(s) Sizing:
•
1 sq.in./4000 Btu per louver
4000 MBH = 1000 in2
of free area per louver.
•
Typical louver has 30-60% free
area.
•
Depending on louver design
actual louver size will be:
 Using 45% free area louvers
= Two 5’ x 4’ louvers
Sub Title
2000 MBH 2000 MBH
Codes and Standards
Code Requirements – Air for Combustion and
Ventilation – Mechanical Combustion Air Supply
(MCAS)
• Z223.1-2002
8.3.6 Mechanical Combustion Air Supply. Where all combustion air is
provided by a mechanical air supply system, the combustion air shall be
supplied from outdoors at the minimum rate of 0.35 ft³/min per
1000 Btu/hr for all appliances located within the space.
Sub Title
8.3.6.1 Where exhaust fans are installed, additional air shall be provided
to replace the exhausted air.
8.3.6.2 Each of the appliances served shall be interlocked to the
mechanical air supply system to prevent main burner operation where the
mechanical air supply system is not in operation.
Codes and Standards
Sizing of Mechanical Combustion Air
Louver Sizing:
• Engineered using ASHRAE
Chimney Design Equation.
Sub Title
• Flue Gas Volume corrected for
temperature
= 1,400 cfm of combustion air
• 1400 cfm/500 fpm
= 2.8 ft2 of louver free area
2000 MBH 2000 MBH
• Using a 45% free area louver
= One 3’ x 2’ louver
MCAS – Modulating Combustion Air
Supply System
Sub Title
MCAS Components – BESF/BESB Fan
Seven Models
450 – 5500 cfm
Sub Title




Fan can be mounted indoors or outdoors.
Impeller - statically and dynamically balanced.
Insulated housing in galvanized steel
Hinged fan housing easily opens to provide easy
access to duct and impeller
 Direct drive, variable speed, TEFC motor located
outside housing for easy access.
 Variable Frequency Drive is used on three phase
models (VFD should be located inside the building).
MCAS Components – SFTA Fan
Seven Models
1,500 – 30,000 cfm
Sub Title




Fan can be mounted indoors
Impeller – cast allunimum.
Housing in steel
Direct drive, variable speed, TEFC motor located
outside housing for easy access.
 Variable Frequency Drive is used on three phase
models (VFD should be located inside the building).
EBC30 Modulating Control
Chimney
Automation
System
Sub Title
Modulating
Combustion
Air Supply
System
MCAS
Mechanical Combustion Air Supply
SBC Center – San Antonio, TX
Sub Title
Two 16 inch ducted combustion air inlets
Instead of
Two 10 foot high by 15 foot long Louvers
Lifetime Fitness – Savage, MN
Sub Title
Marriott Waterfront – Annapolis, MD
Sub Title
One 24 inch ducted combustion air
Instead of one 90 ft.² louver
MDVS
Modulating Dryer Venting System
Types of Clothes Dryers
•
Type 1 dryers: “Domestic” dryers to be used primarily in a family
living environment.
• Residences
• Individual apartments or condominiums
• Type
dryers:
Sub2 Title
“Public” dryers designed to be used in business with
direct intercourse of the function with the public.
• Laundromats
• Laundry rooms (apartment complexes, dormitories, etc.)
• Business laundries (hotels, hospitals, health clubs, etc.)
Typical Dryer Manufacturer’s
Requirements
•
•
•
Where possible use a single exhaust duct per dryer
Dryers are to run with a positive outlet pressure.
• Type 1 dryers between +0.10 and +0.90 inch W.C.
•Sub
Type
2 dryers between +0.10 and +0.30 inch W.C.
Title
Maximum exhaust duct length:
• Type 1 dryers = 35 equiv. feet (each elbow = 5 feet)
• Type 2 dryers = 15 equiv. feet (each elbow = 5 feet)
Typical Dryer Manufacturer’s
Requirements for Multiple Dryers
•
Vertical venting must not exceed 8 feet and can include up to 3 elbows
•
Horizontal venting cannot exceed 15 feet and 1 elbow.
Sub Title
Common Exhausting of Multiple
Dryers
•
•
•
•
Common horizontal duct diameter is sized with
maximum 0.10 inch W.C. pressure drop
Pressure drop in main exhaust shaft is only
limited by fan’s total pressure capability
Cleanouts must be provided in the common
horizontal as well as the main exhaust shaft for
removal of lint
Sub Title
The BESB fan can be located anywhere downstream of the last dryer
Use an MDVS for
Multiple Dryer Exhausting
Multistory exhausting
of dryers
Sub Title
Common exhausting of
multiple dryers
Multistory Exhausting of Dryers
•
•
•
Type 1 or Type 2 dryers
If main exhaust shaft does not need to be fire
rated – attach connector to main shaft at 45° as
previously shown
If main exhaust shaft does need to be fire rated
– attach connector via a 22 inch subduct riser
as shown
•
Main exhaust shaft and subduct riser must
be made of appropriate materials to meet
local codes
•
In order to offset the subducts, a square or
rectangular main exhaust shaft should be
considered
Sub Title
Main Issues when
Common Exhausting Dryers
•
For multistory dryer systems where the 22 inch subduct is used to maintain fire rating, a fan MUST BE USED and it must be in operation at all times to comply
with code requirements
•
IBC 2006
Sub Title
716.5.3 Penetrations of shaft enclosures. Shaft
enclosures that are permitted to be penetrated by ducts
and air transfer openings shall be protected with
approved fire and smoke dampers installed in accordance
with their listing.
Exceptions:
1. Fire dampers are not required at penetrations
of shafts where:
1.1 Steel exhaust subducts extend at least 22 inches
(559 mm) vertically in exhaust shafts pro-vided
there is a continuous airflow upward to
the outside.
2. In Group B and R occupancies, equipped throughout with
and automatic sprinkler system in accordance with
Section 903.3.1.1 smoke dampers are not required at
penetrations of shafts where:
2.1. Kitchen, clothes dryer, bathroom and toilet room
exhaust are installed with steel exhaust subducts,
having a wall thickness of 0.019(0.48 mm); and
2.2 That extend at least 22 inches vertically; and
2.3 An exhaust fan is installed at the upper terminus of
the shaft, that is powered continuously in accordance
with Section 909.11, so as to maintain a continuous
upward airflow to the outside.
Multistory Exhausting of Dryers
•
•
•
Main exhaust shaft is made of smooth (firerated) material
Main exhaust shaft sized to max 0.10 inch W.C.
pressure drop
Access door or cleanout to be located at bottom
of main exhaust shaft for lint removal
Sub Title
•
BESB fan can be located anywhere above top
most dryer
MDVS versus Single Speed
MDVS
•
•
•
Single Speed
ETL Listed mechanical dryer
exhaust system
•
Usually runs at low rpm = low
power
•
Sub Title
Uses little to no conditioned air =
low additional building heat or A/C
•
No listing for lint-laden air
Runs at full rpm 24 hr/day X 365
days/yr = high power
Uses a large quantity of conditioned
air = large additional building heat
and A/C
MDVS versus Single Speed
20 Dryer Multistory Apartment
200 cfm X 20 X 50% = 2000 cfm
MDVS
Fan Power
Single Speed
Savings
41 KW/yr
$4 /yr
4368 KW/yr
$437 /yr
$434 /yr
Loss of heated air
1,454,200
(BTU/yr)
$15 /yr
155,520,000
(BTU/yr)
$1,555 /yr
$1540 /yr
Loss of A/C air
(sensible only)
824,100
(BTU/yr)
$5 /yr
88,128,000
(BTU/yr)
$557 /yr
$552 /yr
Sub Title
Location = Atlanta, GA (3000 DDH, 1700 DDC)
Power = $0.10 per KW/h
Heating = $1.00 per therm
A/C = .75 KW/ton X $0.10 per KW/h
Total Annual Savings = $2526
MDVS – Mechanical Dryer Venting
System
Sub Title
MDVS Components - BESB Fan
Four Models
1200 – 5500 cfm
Sub Title
•
•
•
•
Cast aluminum, backward curved impeller reduces lint build-up.
Statically and dynamically balanced with permanently attached balancing
weights.
Insulated hinged fan housing easily opens to provide easy access to duct
and impeller
Direct drive with variable speed TEFC motor located outside housing for
easy access. Frequency drive should be located inside the building.
ETL Listed to UL705 with special consideration for operation with lint-laden
air
Mechanical Dryer Venting
Systems
Sub Title
MCAS
Modulating Combustion Air Supply
for Dryers
Why MCAS for Dryers?
Make-Up Air.
• Z223.1-2002
9.4 Clothes Dryers.
Sub Title
9.4.3.2 Provisions for Make-Up Air. Provisions for
make-up air shall be provided for Type 2 clothes
dryers, with a minimum free area of 1 sq.in. for each
1000 Btu per hr total input rating of the dryer(s)
installed.
Manufacturer’s Requirement
•
•
•
National Fuel Gas Code requires a minimum free area opening of 1 sq.in./1000 Btuh
Most manufacturers require even larger – approximately 1 sq.in / 700 Btuh. Ex. A twin 30# tumbler dryer
with a total input of 204,000 Btuh (1100 cfm) requires a minimum 2 sq.ft. free area opening.
Most laundry facilities have problems with make-up air. The industry believes it is one of their biggest
problems.
Sub Title
MCAS Components – SFTA Fan
Seven Models
1,500 – 30,000 cfm
Sub Title




Fan can be mounted indoors
Impeller – cast allunimum.
Housing in steel
Direct drive, variable speed, TEFC motor located
outside housing for easy access.
 Variable Frequency Drive is used on three phase
models (VFD should be located inside the building).
Marriott Waterfront – Annapolis, MD
Sub Title
One 24 inch ducted combustion air inlet
Instead of
One 90 ft.² louver
Simulators
CASV / MCAS
MDVS
Sub Title