NFI Core Review Class Flashcards

Questions and Answers

What are the 4 stages of combustion?

Char burning (correct)

Moisture evaporation (correct)

Ignition of combustible gas (correct)

Release of combustible gases (correct)

What is the total energy produced by burning one pound of wood?

8,600 BTUs

What is the ignition temperature of wood smoke when using catalytic converters?

500 degrees

What is the proper UL Standard for chimneys used to vent wood stoves?

UL103HT Signup and view all the answers

What do the UL103HT requirements cover?

Factory-built chimneys for gas, liquid, and solid-fuel fired appliances Signup and view all the answers

According to NFPA 211, the maximum horizontal run of a wood stove connector is limited to ______________ percent of the vertical portion of the chimney above the connector.

50% Signup and view all the answers

According to NFPA 211, a manual damper installed in a wood stove connector pipe cannot block more than ___________ percent of the connector when fully closed.

80% Signup and view all the answers

According to NFPA 211, the maximum permitted chimney flue area is __ times the appliance flue collar area for exterior chimneys and times the appliance flue collar area for interior chimneys.

2 and 3 Signup and view all the answers

The maximum chimney offset angle permitted in the United States is __________ degrees (from vertical).

30 degrees Signup and view all the answers

According to NFPA 211 and the IRC, a 3.5" brick wall with a 1" ventilated air space provides a __________ percent clearance reduction.

66% Signup and view all the answers

According to NFPA 211 and the IRC, a 3.5" brick wall without ventilated air space provides a __________ percent clearance reduction.

33% Signup and view all the answers

According to NFPA 211 and the IRC, a 24 gauge sheet metal panel with a 1" ventilated air space provides a __________ percent clearance reduction when used as a ceiling protector.

50% Signup and view all the answers

The standard clearance to combustibles for an unlisted wood stove is ___________ inches.

36 Signup and view all the answers

What is UL 1618?

2 types of manufactured pads Signup and view all the answers

What is Type 1 floor protection?

Can be used on appliances that do not require thermal protection Signup and view all the answers

What is Type 2 floor protection?

For appliances requiring thermal protection and must have an R value of 1.0 Signup and view all the answers

What is R-value?

Measure of heat resistance Signup and view all the answers

Who writes gas products standards?

ANSI (American National Standards Institute) Signup and view all the answers

What does ANSI Z21.50 apply to?

Newly produced vented decorative gas appliances Signup and view all the answers

What does ANSI Z21.8 cover?

Installation of a conversion burner Signup and view all the answers

What does ANSI Z21.9 refer to?

Outdoor decorative appliances Signup and view all the answers

What does ASTM E-1509 represent?

Standard specs for room heaters and pellet fuel burning Signup and view all the answers

What are the emission limits in the New Source Performance Standard (NSPS) for catalytic and non-catalytic woodstoves?

4.5 grams/hour and 7.5 grams/hour Signup and view all the answers

According to NSPS, what are the two phases for woodstoves?

Current: 4.5 grams/hour and by 2020: 2.5 grams/hour with cord wood, 2.0 grams/hour with crib wood Signup and view all the answers

What are the principles of draft and flow?

Exhaust flue gases to outside, protects home from hot gases and sparks, causes combustion air to be drawn in Signup and view all the answers

What is natural draft?

Force that moves air into the appliance and combustion byproducts out due to temperature differences Signup and view all the answers

What is flow in the context of chimney systems?

Volume of gases that pass through venting system as a result of draft Signup and view all the answers

What is a house stack effect?

Heated portion of the house taller than vent termination creates a greater chimney effect Signup and view all the answers

What is mechanical draft?

Can correct venting issues and is listed and installed according to instructions Signup and view all the answers

Draft gauges are measured in____________.

Water Column Inches Signup and view all the answers

What is the chimney connector pipe?

The pipe coming off the appliance and connecting to the chimney Signup and view all the answers

Study Notes

Combustion Stages

Four stages of combustion: moisture evaporation, release of combustible gases, ignition of combustible gas, and char burning.

Energy Production

Burning one pound of wood generates approximately 8,600 BTUs.

Ignition Temperature

Catalytic converters can reduce the ignition temperature of wood smoke to around 500 degrees.

UL Standards for Chimneys

Proper UL Standard for chimneys venting wood stoves is UL103HT.

UL103HT Details

Covers factory-built chimneys for venting gas, liquid, and solid-fuel residential-type appliances.

Wood Stove Connector Limitations

Maximum horizontal run of a wood stove connector is limited to 50% of the vertical chimney portion above the connector.

Manual Damper Regulations

A manual damper in a wood stove connector pipe must not block more than 80% of the connector when fully closed.

Chimney Flue Area Regulations

Maximum chimney flue area: 2 times the appliance flue collar area for exterior chimneys; 3 times for interior chimneys.

Chimney Offset Angle

Maximum permitted chimney offset angle in the U.S. is 30 degrees from vertical.

Clearance Reduction Specifications

A 3.5" brick wall with 1" ventilated air space provides a 66% clearance reduction.
A 3.5" brick wall without ventilated air space provides a 33% clearance reduction.
A 24 gauge sheet metal panel with 1" ventilated air space offers a 50% clearance reduction as a ceiling protector.

Clearance to Combustibles

Standard clearance to combustibles for unlisted wood stoves is 36 inches.

UL 1618 Understanding

UL 1618 provides two types of manufactured pads for floor protection: Type 1 for ember protection; Type 2 for thermal protection (requires an R value of 1.0).

R-Value Definition

R-Value measures heat resistance, indicating thermal efficiency.

Gas Product Standards

Gas product standards are outlined by ANSI (American National Standards Institute).

ANSI Standards Overview

ANSI Z21.50: Standards for newly produced vented decorative gas appliances.
ANSI Z21.8: Standards for installation of conversion burners.
ANSI Z21.9: Standards for outdoor decorative appliances.

Room Heater Standards

ASTM E-1509 specifies standards for room heaters and pellet fuel burning.

Emission Limits under NSPS

New Source Performance Standard emission limits set: 4.5 grams/hour for catalytic stoves and 7.5 grams/hour for non-catalytic stoves.

NSPS Phases for Woodstoves

NSPS consists of two phases:
- 1st phase: current limit is 4.5 grams/hour.
- 2nd phase (by 2020): reduction to 2.5 grams/hour with cord wood and 2.0 grams/hour with crib wood.

Principles of Draft and Flow

Ensures exhaust flue gases exit to the outside, protects the home from hot gases and sparks, and draws in combustion air.

Natural Draft Dynamics

Natural draft moves air into the appliance and expels combustion byproducts due to the temperature difference between gases and outside air.

Flow Definition

Flow refers to the volume of gases that traverse the venting system due to draft.

House Stack Effect

Occurs when a heated house portion is taller than the vent termination, creating additional chimney effect due to leaks and upper-window openings.

Mechanical Draft Utility

Mechanical draft systems can remedy venting issues but must be listed and installed per specific instructions.

Measurement of Draft Gauges

Draft gauges are measured in Water Column Inches.

Chimney Connector Pipe Function

The chimney connector pipe connects the appliance to the chimney and is critical for proper venting.

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Description

Test your knowledge with these flashcards covering essential concepts from the NFI Core Review Class. Learn about the stages of combustion, energy output of wood, and the role of catalytic converters in reducing ignition temperatures. Perfect for those preparing for certification or looking to enhance their expertise in fire science.