Fire Detectors

This page explains the parameters that define a fire detector in Kryptos. For more details on where to enter these values, see Fire Mapping Parameters.

What Defines a Fire Detector?

A fire detector in Kryptos is characterized by four parameters: Horizontal Field of View, Vertical Field of View, Curvature and Range.

Selecting a detector model from the Detector Database automatically populates its field-of-view angles and curvature. The detection ranges are configured separately for each grade and alarm level. Selecting Custom in the Detector drop down allows you to enter the detector parameters manually.

Field of View

A fire detector can detect fires only within its field of view (FOV), which defines the angular extent of its detection volume. It is described by two angles:

• FOV Horizontal (°) — the horizontal angular width of the detector's field of view.
• FOV Vertical (°) — the vertical angular height of the detector's field of view.

These values are typically specified in the manufacturer's datasheet.

A detector with a wide horizontal field of view and a narrow vertical field of view has a broader horizontal coverage area but a more restricted vertical extent. A detector with equal horizontal and vertical angles has a more symmetrical field of view.

The direction in which the field of view points is determined by the detector's orientation, configured through the detector's horizontal and vertical tilt when placing it.

Curvature

Curvature defines the shape of the boundary at the far edge of the detector's detection volume.

The field-of-view angles define the angular extent of the detection volume, while the range defines its maximum detection distance. Without curvature, the detection volume would terminate at a flat surface at the maximum range.

Curvature modifies the shape of this maximum range boundary, allowing the detection volume to represent the detector's sensitivity characteristics more realistically.

The appropriate curvature value should be obtained from the detector manufacturer's specifications or alternatively, the corresponding detector model in Kryptos' Detector Database.

Range

Range defines the maximum distance at which a detector can detect a fire, expressed in the project's selected units.

The detection range is configured separately for each Risk Grade in the Fire Ranges table. This is necessary because a detector's effective detection distance depends on the fire size being assessed. A detector may have a longer detection range for a larger fire and a shorter range for a smaller fire.

Ranges are also specified separately for each alarm level:

• Low Alarm (L)
• High Alarm (H)

Consequently, the detection range can differ by both Risk Grade and alarm level.

TIP

A detector does not have a single detection volume that applies to every risk grade. Its effective detection volume depends on the configured range for the selected risk grade and alarm level, together with its field of view and curvature.

This is why fire coverage results are evaluated and reported separately for each grade and applicable alarm configuration.

Related

• Fire Calculation Methods — understand how Kryptos determines whether a fire is detected at a mapping point.
• Area Settings — configure detector models and fire mapping parameters for an area.