Institutional Building

A building with mixed occupational activities where special requirements arising from those activities may be needed such buildings include hospitals, prisons etc.

Insulated Shutters

Insulating panels that cover a window opening to reduce heat loss.

Insulating Board

A building board made of compressed plant fibers, e.g., wood, cane, corn, stalks, dried and pressed to a specific thickness.

Insulating Glass

Two or more pieces of glass spaced apart and hermetically sealed to form a single glazed unit with one or more air spaces in between. Also called double glazing.

Insulating Value For Windows

See U-factor.

Insulation

Any material used to reduce the transfer of heat, cold or sound.  Three basic types of insulation used in residential construction are rock wool, fiberglass and cellulose. Insulation is available as a batt or loose fill. Batts are either fiberglass or rock wool spun together to form a continuous piece of insulation. Insulation is rated by its R-Value, which determines the resistance to the flow heat. The higher the R-Value the greater the insulating efficiency. Insulation ranges in R-Value from R-11 to R-38. Loose fill insulation includes any of the above substances and is blown into ceilings or walls.

Insulation

Construction materials used for protection from noise, heat, cold or fire.

Insulation / Economic Thickness Of Insulation

A thickness, giving the largest energy savings for the lowest investment costs.

Intentional Ventilation

Ventilation provided through the use of purpose provided openings, such as through windows or airbricks.

Interior Trim

The finish on the interior of a building e.g., casing, molding, baseboard.

Interlocker

An upright frame member of a panel in a sliding glass door which engages with a corresponding member in an adjacent panel when the door is closed. Also called interlocking stile.

Interlocking Shingles

Individual shingles that mechanically fasten to each other to provide wind resistance.

Inverter

Mitsubishi Electric's MSZ and MXZ outdoor units use inverter compressor technology (Variable Frequency Drive) to provide exceptional indoor, high-speed cooling and heating. By responding to indoor temperature changes, these systems reduce power consumption by varying the compressor speed for extra energy savings. The system operates only at the levels needed to maintain a constant and comfortable indoor environment.

Inward

Directed toward the interior.

IPLV - Integrated Part  Load Value

A single number, part-load efficiency indicator calculated using the ARI method at standard rating conditions. Introduced in ARI Standard 550-1986, the definition of IPLV was changed in ARI Standard 550/590-1998 to more closely reflect actual operating experience found in the field for a single chiller.

IWC

An acronym for Inches of water column, still commonly used in the USA. An old measure of air pressure used in HVAC systems.

Jalousie

Window made up of horizontally-mounted louvered glass slats that abut each other tightly when closed and rotate outward when cranked open.

Jalousies

Adjustable glass louvers in doors or windows that regulate light and air or exclude rain.

Jamb

The side framing or finish of a doorway or windows.  A vertical member at the side of a window frame, or the horizontal member at the top of the window frame, as in head jamb.

Jetty

In construction, the projection parts of a structure e.g., a bay window, a balcony.

Joint

The point where two objects or surfaces meet the space between units in a masonry wall that is occupied by mortar or bonding material.

Joint Compound

Plaster-like material used along with wallboard tape to fill and finish joints between gypsum board panels.

Joist

One of a series of parallel beams used to support floor and ceiling loads, and supported in turn by larger beams (girders) or bearing walls. Evenly spaced, horizontal lengths of lumber that provide structural support for floors and ceiling.

Joule

The Thomson Effect-Change in temperature of a gas on expansion through a porous plug from a high pressure to a lower pressure.

Journal, Crankshaft"

A part of shaft which contacts the bearing.

Junction Box

A box in an electrical systems where main circuits are connected or smaller circuits join the main circuit.  A group of electrical terminals housed in protective box or container.

Kata Thermometer (K)

A large bulb alcohol thermometer used to measure air velocities or atmospheric conditions by means of cooling effect.

Kelvin Scale (K)

A thermometer scale on which unit of measurement equals the centigrade degree and according to which absolute zero is 0 deg., the equivalent of -271.16 deg. C. Water freezes at 273.16 deg. And boils at 373.16 deg.

Keystone

A wedge-shaped or trapezoidal structural piece that forms the center unit at the top of a masonry arch.

Kilometer

A unit of electrical power, equal to 1000 watts.

Kilowatt (Kw)

A kilowatt equals 1,000 Watts. A kilowatt hour (kwh) is the amount of kilowatts of electricity used in one hour of operation of any equipment.

Knee Brace

A diagonal member (usually at a 45 degree angle) that is attached from a piling to a main structural beam or girder and serves to stiffen the foundation.

Knob And Tube Wiring

Old electrical wiring on ceramic knobs and tubes secured to structural members of a property.

Krypton

An inert, nontoxic gas used in insulating windows to reduce heat transfer.

Kw/Ton

A kilowatt (Kw) is a measure of electrical energy. A ton is a measure of cooling and is defined as 12,000 BTU of cooling per hour.

Lag

A delay in the effect of a changed condition at one point in the system, or some other condition to which it is related. Also, the delay in response to the sensing element of a control loop due to the time required for the sensing element to sense a change in the sensed variable.

Lamella Roof Structure

An arched, roof-framing structure composed of planking arranged in diamond shapes.

Laminar Flow

Smooth undisturbed flow of a fluid.

Laminate

To build up with layers of wood that are held together in a single unit used to produce plywood and laminated beams. One layer is called a lamination or ply.

Laminated Floor

A floor deck made by gluing or spiking two-by-fours or planks together.