CSA ANSI Z21.91-2017 pdf free download – Ventless firebox enclosures for gas-fired unvented decorative room heaters.
Electrical diagrams —
Connection – a diagram that shows the connections of an installation or its component devices orparts. It may cover internal or external connections, or both, and contains such detail as is neededto make or trace connections that are involved.The Connection Diagram usually shows generalphysical arrangement of the component devices or parts.
Schematic – a diagram that shows, by means of graphic symbols, the electrical connections andfunctions of a specific circuit arrangement. The Schematic Diagram facilitates tracing the circuit andits functions without regard to the actual physical size, shape, or location of the component devicesor parts.
Ladder form of schematic – a diagram drawn in the form of a vertical ladder. The outer verticallines represent the electrical supply conductors. The horizontal steps represent each individualcircuit with all component devices.
Excess air – air that passes through the combustion chamber and the appliance flues in excess of whatis required for complete combustion.
Firebox canopy – a decorative trim piece on the front of the fireplace to deflect the flue products awayfrom the mantel.
Flue gases – products of combustion and excess air.
Heating surface — all surfaces that transmit heat directly from flames or flue gases to the medium tobe heated.
Heating value (total) 一 the number of British Thermal Units produced by the combustion at constantpressure of 1 cubic foot of gas, when the products of combustion are cooled to the initial temperatureof the gas and air, when the water vapor formed during combustion is condensed, and when all thenecessary corrections have been applied.
Input rating — the gas-burning capacity of an appliance in Btu per hour as specified by the
manufacturer.Appliance input ratings are based on sea level operation and need not be changed foroperation up to 2,000 feet elevation.For operation at elevations above 2,000 feet, input ratings shouldbe reduced at the rate of 4 percent for each 1,000 feet above sea level.
Listed — equipment or materials included in a list published by an organization acceptable to the
authority having jurisdiction and concerned with product evaluation that maintains periodic inspectionof production of listed equipment or materials and whose listing states either that the equipment ormaterial meets appropriate standards or has been tested and found suitable for use in a specifiedmanner.
Manifold – the conduit of an appliance that supplies gas to the individual burners.Mixer — the combination of mixer head, mixer throat, and mixer tube.
Mixer head – the portion of an injection-type burner, usually enlarged, into which primary air flowsto mix with the gas stream.
Mixer throat – the portion of the mixer, which has the smallest cross-sectional area, that liesbetween the mixer head and the mixer tube.
Mixer tube — the portion of the mixer that lies between the throat and the burner head.
Mixer face – the air inlet end of the mixer head.
Noncombustible material – material that is not capable of being ignited and burned, such as materialsconsisting entirely of, or a combination of, steel, iron, brick, tile, concrete, slate, asbestos, glass, andplaster.
Normal inlet test pressures – those pressures specified for testing purposes at which adjustment ofburner ratings and primary air adjustments are made.
orifice – the opening in an orifice spud or other device whereby the flow of gas is limited and throughwhich the gas is discharged.
orifice spud – a removable plug or cap containing an orifice that permits adjustment of the flow of gasby substitution of a spud with a different size orifice.
Port – any opening in a burner head through which gas or a gas-air mixture is discharged for ignition.Radiation shield – a separate panel or panels interposed between heating surfaces and jackets toreduce heat losses through radiation.
Safety circuit – a circuit or portion thereof involving one or more safety controls in which failure due togrounding, opening, or shorting of any part of the circuit can cause unsafe operation of the controlledappliance.
Safety shutoff device – a device that will shut off the gas supply to the controlled burner(s) in the event the source of ignition fails. This device may interrupt the flow of gas to the main burner(s) only, orto the pilot(s) and main burner(s) under its supervision.CSA ANSI Z21.91 pdf download.