Potter Releasing Systems - Manual (Page 8)

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National Fire Protection Association [NFPA] - Administers the development of and publishes codes,
standards, and other materials concerning all phases of fire safety.
Non Restorable Initiating Device - A device whose sensing element is designed to be destroyed in the process
of operation.
Notification Appliance - A fire alarm system component such as a bell, horn, speaker, strobe, etc., that provides
an audible or visible output or both.
Notification Appliance Circuit - A circuit directly connected to a notification appliance.
Obscuration - A reduction in the atmospheric transparency caused by smoke. Usually expressed in percent per foot.
Particles of Combustion - Substances resulting from the chemical process of a fire.
Photoelectric Smoke Detector - A smoke detector utilizing a light source and a photosensitive sensor so
arranged that the rays from the light do not normally shine on the photosensitive sensor. When smoke enters the
light path, some of the light reflects off the smoke onto the sensor, causing the detector to respond.
Proprietary Fire Alarm System - An installation of fire alarm systems that serve contiguous and noncontiguous
properties under one ownership from a proprietary supervising station located at the protected property.
Rate Of Rise Heat Detector - A device which will respond when the temperature rises at a rate exceeding a
predetermined amount [usually about 15 degrees per minute].
Remote Station Fire Alarm System - A system installed in accordance with NFPA 72 to transmit alarm, trouble
and supervisory from one or more protected premises to a remote location at which appropriate action is taken.
Residual Pressure - Potential pressure remaining in the system while the system is flowing.
Restorable Initiating Device - A device whose sensing element is not ordinarily destroyed in the process of
operation. Restoration may be manual or automatic.
Riser – The vertical supply pipe in a sprinkler system.
Shall - In NFPA literature indicates a mandatory requirement.
Should - In NFPA literature indicates a recommendation or that which is requested but not required.
Sloping Ceiling - Ceilings having a slope of more than 1½ in. per foot.
A) Sloping - Peaked Type, Ceilings in which the slope is in two directions from the highest point. Curved or
domed ceilings may be considered peaked.
B) Sloping - Shed Type, Ceilings in which the high point is at one side with the slope extending toward the opposite side.
Smooth Ceiling - A surface uninterrupted by continuous projections such as solid joists, beams or ducts,
extending more than 4 in. below the ceiling surface.
Solid Joist Construction - Ceilings having solid structural or nonstructural members projecting down from the
ceiling surface a distance of more than 4 in. and spaced at intervals 3 ft. or less, center to center.
Spot Type Detector - A device whose detecting element is concentrated at a particular location. Examples
include, certain smoke and heat detectors.
Static Pressure - Pressure acting on a point in the system with no flow from the system.
Story - The portion of a building included between the upper surface of a floor and the upper surface of a floor
or roof next above.