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Wood NFI
Solid fuel appliances with legs 6 inches or longer, floor protection must consist of____________________. - Correct Answer โ โ Closely spaced masonry units of brick, concrete, or stone that provide a thickness of not less than 2", and covered with (24) gauge or thicker sheet metal.
NFPA 211 requires that at least ________ inch of open, ventilated airspace be provided between a single-wall connector that passes through a masonry wall used as a wall shield and the masonry. - Correct Answer โ โ 1/
Name the 2 appliance design improvements that have increased efficiency and reductions in emissions. - Correct Answer โ โ 1. Catalytic combustor technology
- Non-catalytic internal appliance design.
Gas log sets that use a FBF for exhaust combustion by-products must be listed to? - Correct Answer โ โ ANSI Z21.60 Decorative Gas Appliance's for installation in solid-fuel appliances.
True or False Thermostats are prohibited for use with vented gas logs.
- Correct Answer โ โ True
True or False; A fire screen must be in place during use of a vented gas log set? - Correct Answer โ โ True
According to ANSI Z21.50 vented gas logs must be equipped with __________ - Correct Answer โ โ an automatic gas ignition shutoff system.
A long run for a chimney connector is generally defined as - Correct Answer โ โ more than 6-8 ft
If off set elbows must be used on a connector it is recommended to have the elbows__________________________ - Correct Answer โ
โ As close to the chimney as possible.
The national regulations did not apply to appliances with: - Correct Answer โ โ - burn rates grater 5kg/hr (11lbs of wood)
- air-to flue ratio > 35 to 1
- firebox > 20 cubic feet
- weight > 800kg or 1760lbs
-coal
-open wood burning
- solid fuel furnaces & boilers
- large industrial and commercial wood fired appliances
Tests showed that these regulations from the 80's showed that - Correct Answer โ โ Emissions from certified appliances were 6kg/hr a reduction of 85%
May 2015 revised EPA regulations step 1 - Correct Answer โ โ - wood, pellet stoves = 4.5gram per hour limit
- Hydronic heaters have a 0.32 lbs per million BTU limit
- Forced air furnaces 0.93lbs per hour limit
May 15 2020 regulations for wood and pellet stoves - Correct Answer โ โ - 2 grams per/hr crib wood
- 2.5 grams per/hr cordwood
Stages of solid fuel combustion - Correct Answer โ โ 1. Moisture Evaporation > 212F
- Release of combustible gases > 500F
- Ignition and combustion of vapors and gases 540-1,225F
- Char burning > 900F
How much water is produced for each pound of wood burned. - Correct Answer โ โ 1/2 lb
At 100% combustion efficiency what byproducts would be produced - Correct Answer โ โ - Water vapor
Chimney connector reduced clearances with wall and ceiling protection:
24 gauge sheet metal over 1" glass fiber or mineral batts reinforced with wire, or equivalent on rear face, with at least 1" ventilated airspace
Max clearance reduction Wall & Ceiling
Min allowed clearance Wall & Ceiling - Correct Answer โ โ Max Wall & Ceiling = 66% / 50% Min allowed = 6"/9"
Chimney connector reduced clearances with wall and ceiling protection:
3 1/2 " thick masonry wall with ventilated airspace:
Max clearance reduction Wall & Ceiling
Min allowed clearance Wall & Ceiling - Correct Answer โ โ Max Wall & Ceiling = 66% / โ Min allowed = 6"/ โ
Chimney connector reduced clearances with wall and ceiling protection:
1/2" thick noncombustible insulation board over 1" glass fiber or mineral wool batts without ventilated airspace.
Max clearance reduction Wall & Ceiling
Min allowed clearance Wall & Ceiling - Correct Answer โ โ Max Wall & Ceiling = 50% / 33%. Min allowed = 9" / 12"
Chimney connector reduced clearances with wall and ceiling protection:
24 gauge sheet metal with at least 1" of ventilated airspace
Max clearance reduction Wall & Ceiling
Min allowed clearance Wall & Ceiling - Correct Answer โ โ Max Wall & Ceiling = 66% / 50% Min allowed = 6"/ 9"
3 1/2" masonry wall no ventilation, as wall protector / as ceiling protector - Correct Answer โ โ 33 1/3% / โโโโ
Maximum allowable clearance reduction from appliances (listed & unlisted)
3 1/2" masonry wall spaced out 1" as wall protector / as ceiling protector - Correct Answer โ โ 66 2/3% / โโโโ
Maximum allowable clearance reduction from appliances (listed & unlisted)
1/2" noncombustible insulation board over 1" glass fiber or mineral wool batts no ventilation, as wall protector , as ceiling protector - Correct Answer โ โ 50% / 33 1/3%
Maximum allowable clearance reduction from appliances (listed & unlisted)
Minimum 24 gauge sheet metal spaced out 1", as wall protector , as ceiling protector - Correct Answer โ โ 66 2/3% / 50%
Maximum allowable clearance reduction from appliances (listed & unlisted)
1/2" noncombustible insulation board over spaced out 1", as wall protector , as ceiling protector - Correct Answer โ โ 66 2/3% / 50%
Maximum allowed clearance reduction from appliance. ( Listed prefabricated systems) - Correct Answer โ โ Per manufactures instructions.
After reduction of listed clearances from appliances, clearances shall not be less than - Correct Answer โ โ 12"
UL 1618 Wall protectors, Floor protectors and hearth extinctions does not allow wall protectors to reduce listed appliance clearances to less than ___________" - Correct Answer โ โ 12
NFPA 211 requires a minimum of __________ inches clearance to combustibles for unlisted woodstoves - Correct Answer โ โ 36
the net free area of the outlet of the flue that it serves. - Correct Answer โ โ 4
A wythe or partition should be constructed of at least ____________" (nominal) thick solid masonry. - Correct Answer โ โ 4
An interior chimney requires a minimum ____________ inch clearance to combustible material - Correct Answer โ โ 2
Concerning interior masonry chimneys: Firestopping with a noncombustible sheet material no greater than __________inch thick, or galvanized steel not less than ______________gague must be installed at every floor and ceiling through which the chimney passes.
- Correct Answer โ โ 1/2 , 26
Interior chimney - Correct Answer โ โ One that has any portion of the chimney within the exterior wall of the building.
Exterior chimney - Correct Answer โ โ Is defined as one that has the entire chimney completely outside the exterior wall of the chimney.
An exterior chimney requires a minimum ________________ inch clearance to combustible material. - Correct Answer โ โ 1
Thimble - Correct Answer โ โ Is a lining for the opening from the room into the chimney, into which the chimney connector is inserted. Also called a breaching..
Thimbles should be constructed by flue liners not less than - ______________inch thick, galvanized sheet metal of_______________ gauge minimum thickness, or noncombustible sheet material not more than __________ inch thick - Correct Answer โ โ 5/8, 24, 1/
UL 1777 liners suitable for use with closed chamber solid fuel hearth appliances are tested to sustained temperatures of _____________
What is the primary function of a Catalyst - Correct Answer โ โ To convert unburned hydrocarbons and CO to compounds that ignite at lower temperatures.
Conditions that reduce the effective surface area of a catalyst are? - Correct Answer โ โ โข plugging
**- masking
- peeling
- substrate deterioration**
Masking - Correct Answer โ โ When the combustor becomes coated with carbon from low oxygen use and/or fly ash.
Peeling - Correct Answer โ โ Extreme temperatures (over 1800F) or flame impingement can cause the cells to peel away from the substrate of a catalytic combustor.
Substrate deterioration. - Correct Answer โ โ Damage to a combustor from...
**- thermal shock
- mishandling
- excessive draft.**
Name the 2 types of firebrick in wood stoves and their characteristics.
- Correct Answer โ โ โข Pumice - Light and high insulating capabilities - Fire clay - heavy and low insulating capabilities.
General guidelines for Minimum and Maximum draft for a wood stove
- Correct Answer โ โ Min = - 0.5-0.
Max = + .10 -.
Minimum clearance for unprotected single wall connector is? - Correct Answer โ โ 18"
The Small crimped end of the chimney connector should be pointed down because? - Correct Answer โ โ This method contains solid and liquid materials inside the connector.
According to NFPA 211, a masonry wall constructed directly against a combustible wall can reduce appliance clearances by no more than? - Correct Answer โ โ 33%
Define an interior chimney? - Correct Answer โ โ A chimney which has "any portion of the chimney within the the exterior wall of the building".
An exterior chimney must be constructed - Correct Answer โ โ Completely outside the exterior wall.
Interior chimneys have a _______" C2C and exterior chimney have a ________" C2C - Correct Answer โ โ 2", 1"
Minimum C2C for an unlisted appliance - Correct Answer โ โ 36"
k-value indicates - Correct Answer โ โ The amount of heat (in BTUs) that will flow in one hour through one sq foot of a uniform material one-inch thick for each degree (F) of temperature difference from one side to the other.
R-value - Correct Answer โ โ Is a measure of a materials resistance to heat transfer.
Formula for converting k to R - Correct Answer โ โ R = (1/k) x inches of thickness
Formula for determining k-value - Correct Answer โ โ (BTU) (inch)
โโโโโโโ
(foot)squared (hour) (F)
What conditions promote creosote buildup; (incomplete combustion)
- Correct Answer โ โ โข Combustion zone temperatures below gas ignition points.
