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64 Cards in this Set
- Front
- Back
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how much do you reduce corrugated liner? |
20% |
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how much must high altitude appliances must be derated? |
10% |
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how much do you reduce each elbow in a vent? |
10% |
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when a draft hooded appliance has more than two 90° elbows on a vent connector, how much should it be de rated? |
10% |
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when a fan assisted appliance on a vent connector has more than two 90° elbows, how much should it be de rated? |
15% |
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if you were to reduce a fan assisted appliance from 4" to 3" .... how much do you reduce from the vent sizing tables? |
10% |
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the minimum size of a vent or vent connector? |
equal to 3" in diameter |
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minimum size of a vent or chimney if it's not round? |
2" |
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what is the size of the vent connector serving a single appliance? |
same size as the draft hood |
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what is the size of a common vent connector serving a single appliance with multiple draft hood outlets? |
the combined area of all the outlets |
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what is the minimum size of a chimney serving a single appliance? |
one size larger than the vent connector |
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what is the formula to size a vent serving multiple appliances? |
100% of the area of the largest output +50% of the rest |
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what is the minimum size (area) of a chimney? |
12 in² (77cm²) |
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what is the maximum size of a masonry chimney for a given installation? |
not to exceed the appliances input by more than 25% |
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what is the minimum height of an air supply inlet above ground? |
6" |
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what is the minimum size of an opening screen, Louvre, or grille used for air supply? |
1/4" |
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what is the maximum developed length of an air supply duct allowed without increasing in size? |
20' |
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what is the minimum area for a square or rectangular duct used for air supply? |
9 in² |
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what type of damper is allowed for installations on an air supply duct in a dwelling unit? |
a certified automatic damper |
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where should an air supply duct terminate? |
next to the burner of the largest appliance |
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what is the minimum size of a fresh air intake and duct? |
4" |
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what two types of buildings are there? |
-loose construction -air tight |
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what type of building is loose construction? |
type B |
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what type of building is air tight construction? |
type A |
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all houses, old or new, are considered to be _______ unless told otherwise |
classed as air tight |
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where must air supply openings and ducts be located? |
1 ft above burner level 2 ft horizontally |
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what would be declared if a zero is entered into the tables of a loose building? |
no outdoor air supply is needed |
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what appliance does ROT only apply for? |
Category 1 Natural Draft Hood |
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when do you not use ROT sizing |
when sizing fan assist appliances |
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how far must a chimney terminate above a roof? |
3 ft |
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how far must a chimney be above any obstruction within 10 ft? |
2ft |
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what is the minimum gauge thickness for a vent connector ? |
28 GSG |
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what is the gauge thickness for an incinerator? |
20 GSG |
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what must be used since a single wall vent connector cant pass through a wall or ceiling? |
type B |
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what is the purpose of the 16 GVRs? |
they are used to "tailor" the vent sizing table to reflect the installation scenarios |
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what is the minimum clearance to unprotected combustibles for a single wall vent? |
6" |
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what is the minimum clearance to unprotected combustibles for type B vent? |
1" |
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if the clearance of a single wall vent connector is protected by combustibles, what can the clearance be reduced to? |
2" |
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how much larger should a ventilated thimble be if the vent connector is 6 ft or less long? |
4" |
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how much larger shall a ventilated thimble be if the vent connector is more than 6 ft long? |
2 " |
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how many BTUs is 1 sq in of a power burner? |
30 000 |
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how many BTUs is 1 sq in of an appliance over 1 million MBH |
14,000 |
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how many BTUs is 1 sq in of an appliance under 1 million? |
7000 |
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what is the minimum vent height? |
5 ft from the highest draft to the rain cap |
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when can you reduce the size of a draft hooded appliance from 5" to 4" ? |
when the vent is 10 ft high |
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what is the maximum length of a common vent connector? |
1.5 ft for every inch of diameter |
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when shall an outdoor air supply not be required? |
when a single water heater with an input of 50 000 btuh or less with no other appliances in the structure. |
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how many openings must there be for one or more natural draft hood appliances? |
2 |
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where must the openings be located for the natural draft hooded appliances? |
-no more than 18" from the ground and not less than 6" -as high as possible to the cieling but no lower than the opening of the lowest draft hood. |
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where shall an air supply duct be located from a moisture exhaust duct? |
3 ft |
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how high must an air supply inlet be above grade |
12" above the outside ground |
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what type of damper or louvers shall not be used? |
-manually operated damper -manually adjustable louvers |
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where are BW vents only used? |
recessed wall heaters |
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what is required when a mechanical air supply is used? |
the mechanical unit must be interlocked with the appliance it serves |
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what is the minimum size of opening for air supply? |
10 in² |
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where do type A buildings get their air supply? |
Outdoors |
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where do type B buildings get their air supply? |
ALL from outdoors or ALL from inside |
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when a duct exceeds 50 ft, instead of upsizing by 1 size, what must be done? |
require a mechanical engineer |
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the atmospheric pressure inside a building having a category 1 appliance installed must not be allowed to drop more than .... |
5 pascals or 0.02" of WC |
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what is the pressure inside a vent? |
-0.03 to -0.1 inch water column |
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how much does a category 4 appliances terminate above a roof? |
18" |
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what is the maximum length of a comment vent connector? |
1.5 ft for each inch of diameter |
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how is the commen vent height measured for two or more gas fired appliances? |
from the highest draft good connection to the rain cap |
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when must you never use rule of thumb for? |
category 1 fan assisted appliances |
