Glossary of Industrial & Commercial Chimney Terms

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

A

AHJ – Authority Having Jurisdiction. Refers to governmental organization or designated individual with legal responsibility for building codes, standards and inspection.

Air Quality Standards – The level of pollutants prescribed by law or regulation that cannot be exceeded during a specified time in a defined area.

AL 29-4C® - Superferritic stainless steel used in UL 1738 listed chimneys for venting Category II, III & IV appliances

Aluminized Steel - Steel which on which an aluminum coating is applied to resist corrosion.

Ambient Temperature - The temperature at a point or area expressed as an average of the surrounding areas or materials. Ambient temperature is generally given to be 70-80°F (21 TO 27°C); an average of daily and seasonal variation.

Andirons - Two pieces of metal designed to support firewood in a firebox.

Ash Pit - A storage compartment for ashes, located in the chimney base.

Ash Pit Door - A door found in the floor of the firebox that provides access to the ash dump, through which ashes can be dumped into the ash pit.

ASHRAE - American Society of Heating, Refrigerating and Air Conditioning Engineers. Schebler Chimney Systems is a member.

ASME - The American Society of Mechanical Engineers. Schebler certification: ASME code for pressure vessel fabrication and repair.

Atmospheric Appliance - An appliance which requires natural draft for venting. Venting is under negative pressure.

B

B-Vent - A type B venting product with an aluminum inner liner and galvanized outer shell. Rated to 550 degrees. Non positive pressure rated.

Barometric Damper - A balanced air damper to allow outside air into the vent system to equalize the draft.

Barometric Pressure - Atmospheric pressure as determined by a barometer

Blower - A fan used to force air under pressure.

Boiler - A closed vessel in which water or other fluid is heated. The heated or vaporized fluid exits the boiler for use in various processes or heating.

Boiler Efficiency - Difference between the energy input and energy output in a boiler.

Boiler Horsepower - Measure of a boiler’s capacity to produce steam.

Breast - The area located above the damper on the front smoke chamber wall of a masonry fireplace.

Breeching - The horizontal portion of a chimney system or grease duct from the boiler, hot water heater, generator, dish washer or kitchen appliance hood to the vertical portion of the system.

BTU - British Thermal Unit. One BTU is the amount of heat energy needed to raise the temperature of one pound of water by one degree F. It is approximately the amount of heat produced by one lighted kitchen match.

Building Heating Appliance - A fuel-burning or electric boiler operating at a gauge pressure not over 50psi.

Burner - A burner introduces the mixture of fuel and air into an appliance at the desired rate per the specific Appliance requirements.

C

Category I Appliance - An appliance that operates with a nonpositive vent static pressure and with a vent gas temperature that avoids excessive condensate production in the vent.

Category II Appliance - An appliance that operates with a nonpositive vent static pressure and with a gas vent temperature that is capable of causing excessive condensate production in the vent.

Category III Appliance - An appliance that operates with a positive vent static pressure and with a vent gas temperature that avoids excessive condensate production in the vent.

Category IV Appliance - An appliance that operates with a vent static pressure and with a vent gas temperature that is capable of causing excessive condensate production in the vent.

Chase - An enclosure for a "Class A" or factory-built chimney which hides the metal chimney from view.

Chimney - One or more passageways, vertical or nearly so, for conveying flue gases to the outside atmosphere

Chimney Cap Or Flue Cap - A factory-fabricated appliance that is installed on the chimney top to protect the chimney from water intrusion, birds, leaves and other debris.

Clean Out Door - An door located on the exterior base of the chimney which provides access into the ash pit for the purpose of removing ash.

Clearance to Combustibles - Distance required per UL listing between the single wall liner, or outer shell of the double wall products to combustible material such as a shaft, roof, etc.

Condensate - The liquid that separates from gas, including flue gas, due to a reduction in temperature.

Corrosion - Eating away of metal due to chemical reaction. Schebler’s continuous seam welding and absence of spot welds minimizes chimney corrosion. (SEE Solutions > Corrosion Resistant)

Creosote - Chimney and stovepipe deposits originating as condensed wood smoke having three stages. 1st stage is soot, 2nd stage is lumpy and crisp, 3rd stage looks like roofing tar and is smooth as glass.

cUL – Canadian Underwriters Laboratory. Schebler products carry specific certifications indicating satisfaction of safety standards set by Canadian Underwriters Laboratories. Also indicated by ULC.

D

Damper - A moveable blade located in the throat of the fireplace. Designed to impede air flow into the chimney.

Dew Point - The temperature at which condensation starts.

Diameters, chimney – At up to 18’ in diameter, Schebler chimneys are the largest available. In any application, chimney diameters greater than 26” reduce cost and space of venting multiple boilers – fewer stacks, fewer roof penetrations, lower costs.

Dimensional Accuracy – A Schebler Chimney Systems advantage, providing value in the way of installation ease, improved pitch and lowered rework.

Direct vent - Double wall pipe where exhaust air is removed by the liner and combustion air is brought into the appliance between the inner liner and outer wall.

Double Wall – A chimney constructed of an inner liner and outer shell, reducing conduction of heat to the outside. This allows the chimney to be installed without combustion danger to support materials.

Draft -The rising gas creates a pressure difference called draft, which draws combustion air into the appliance and expels the exhaust gas outside through the chimney.

Draft Hood - Located at the top of an atmospheric appliance where the breeching or chimney connects. Draft hood helps bring outside air into the vent to help draft.

E

Efficiency - The ratio of input of energy to output of energy

Engine Generator - device that converts mechanical energy into electrical energy with its own engine.

Engineered Stack - A chimney that is engineered to be self-supporting or free-standing. Schebler’s engineered stack expertise includes sizing, design, engineering, fabrication and installation. (See Engineered Stacks)

eVent SeriesTM - Prefabricated chimney system for high-efficiency condensing boilers. Three models are available in odd and even sizes from 5" to 48". UL 1738-Listed, corrosion-resistant, 24 and 20 gauge, AL 29-4C stainless steel products. (See Prefabricated Chimneys for links to all eVent models).

F

Factory-Built Fireplace - Metal fireplace components, fabricated in a factory and field installed.

Field Fabricated - Non UL fabrication of grease duct, flue, breeching or chimney products.

Firebox - The area that contains the grate or andirons upon which the materials are arranged for combustion.

Firebrick - Heat refractory brick used in the construction of a firebox.

Fireplace - Hearth, firebox, fascia and chimney.

Flashing - Sheet metal used to make a water-tight seal between the chimney and the roof.

Flange Connection - ½” rolled lip on Schebler products that allows secure connection of products. Schebler’s flange connection increases pressure rating and eliminates condensate leakage.

Flanged Boiler Connection - Boiler outlet that has a rolled lip and requires a flanged boiler kit.

Flue - The passage in the chimney which moves the products of combustion up and out of the chimney top.

Flue Liners - Materials that add protection to the inside of the chimney, protecting it from intense heat.

Flue Gas - The product of combustion from the appliance through the breeching and/or chimney into the atmosphere.

Forced Draft - Air under positive pressure produced by fans at the point where air or gases enter a unit, such as a combustion furnace.

G

Grease Duct - UL listed or field fabricated system conveying grease laden vapors from a cooking appliance to the atmosphere by means of a fan. Schebler ducts are UL-tested for temperatures up to 2000 degrees F.

Generator - a device that converts mechanical energy into electrical energy.

Grate - Raised grid-like metal structure where fuel is placed in the firebox.

Guy Section – a bracing attachment for tall chimney structures that provides protection from wind displacement.

H

Hearth (Inner) - The floor of the firebox.

Hearth (Outer) - The area in front of the firebox opening which is constructed of non-combustible material.

Heavy Wall Fabrication – An integral part of Schebler engineered stack production, featuring AWS-certified welders with expertise in a variety of high-integrity metals.

I

IMC - International Mechanical Code. Establishes minimum regulations for mechanical systems using prescriptive and performance-related provisions.

Induced Draft Fan - A fan located inside a system to assist exhaust of flue gas.

Insulation – Ceramic fiber material of various thicknesses used in Schebler chimney models to reduce cold-face temperatures and lower building cooling loads; to enable tight installations by reducing clearance to combustibles; and to diminish heat loss in low temperature environments.

ISO – International Organization for Standardization. Schebler’s ISO 9001:2000 certification indicates fulfillment of worldwide quality management requirements.

L

Liner – The interior component of a double-wall chimney. Schebler 304, 317 and AL29-4C stainless steel liners are designed to last for decades under a variety of uses and conditions.

M

Make Up - Outside air introduced into mechanical room to help draft.

N

NFPA - National Fire Protection Association – an International Codes and Standards Organization.

NFPA 37 - Standard for the installation and use of stationary combustion engines and gas turbines.

NFPA 96 - Standards for ventilation control and fire protection of commercial cooking operations.

NFPA-211 - Standards for chimneys, fireplaces, vents, and solid fuel burning appliances.

O

Obround – a space-conserving chimney shape consisting of two semicircles connected by parallel straight sides.

P

PAL - Model PAL (pipe-air gap-liner) for high-efficiency boilers is a pre-fabricated Schebler exclusive. Available in even and odd sizes from 5” to 48”, it features thicker-than-standard wall material and continuous seam welding. (See Products for information on all Schebler prefabricated chimneys)

R

Rain Test – UL test indicating that an unsatisfactory amount of water does not enter the rain cap of a chimney.

S

Skin Temperature Rise Tests – UL study subjecting a chimney to a series of burn tests at temperatures up to 1800 degrees F. Determines safe clearances from the chimney outer shell to combustible materials.

Stack - A vertical conduit, which due to the difference in density between internal and external gases creates a draft at the base. Used interchangeably with vent & chimney.

Stainless Steel - Material with different levels of corrosiveness used as the liner in UL listed chimneys and grease duct.

Structural Tests – UL study indicating support plates and wall supports have been physically tested to carry a load four times that allowed by the UL listing.

T

Thermal Expansion - Alteration to temperature inside a chimney or grease duct system that causes the metal surfaces to expand.

Tool-less End Cap - UL listed end cap used on grease duct that doesn’t require tools to remove, making inspection and cleaning easier at clean out locations.

U

UL - Underwriters Laboratories. Schebler Chimney Systems products carry specific certifications indicating satisfaction of safety standards set by Underwriters Laboratories. cUL and ULC refer to Canadian requirements.

UL 103 - Safety standard for prefabricated chimneys intended for venting gas, liquid, and solid-fuel fired residential-type appliances and building heating appliances.

UL 1738 - Safety standard for venting systems intended for gas-burning appliances, Categories II, III, and IV

UL 1978 - Standard for grease ducts and their clearance to combustibles.

UL 2221 - Indicates a zero clearance to combustibles for fire-resistive grease ducts.

V

Vee Band - A stainless steel V-shaped band that draws the flanges together on two pieces of Schebler Chimney products, securing them together.

Vent - A continuous passage from the flue collar to the draft hood. Flue gas temperatures at the outlet do not exceed 600 degrees.

W

Water Column - The amount of gas pressure necessary to displace a column of water a specified number of inches. 28 inches of water column equals 1 psi.