A smoke detector includes a tamper indicator that can prevent a cover from at least partially covering a battery location and/or mounting of a detector body to a detector mount if a battery is not located at the battery location of the detector body. The detector mount and/or cover can engage with the detector body by relative rotation about an engagement axis, and the tamper indicator can pivot about a pivot axis that is parallel to the engagement axis and/or move along a linear path. The tamper indicator can prevent engagement of a portion of the detector mount, such as an intermediate component between the detector body and a base of the detector mount, with the detector body. The intermediate component can at least partially cover the battery location when engaged with the detector body. The base of the detector mount can engage with the detector body via the intermediate component.

A sensor guard and method of using the sensor guard to protect a sensor element of a fire sensor. The sensor guard includes one or more legs that extend in a direction that is oblique to a central axis of the fire sensor. The fire sensor includes a housing and the sensor element, extending from the housing, for detecting an indication of fire. The sensor guard is mounted on the housing for protecting the sensor element.

A sensor guard and method of using the sensor guard to protect a sensor element of a fire sensor. The sensor guard includes one or more legs that extend in a direction that is oblique to a central axis of the fire sensor. The fire sensor includes a housing and the sensor element, extending from the housing, for detecting an indication of fire. The sensor guard is mounted on the housing for protecting the sensor element.

The invention relates to a system for building automation including at least one smoke and/or fire detector, at least one adapter that is coupleable with the smoke or fire detector; and one or plural functional units which are connected or connectable with the adapter. The building also relates to a building automation method.

An alarm apparatus, for detecting radiation and/or pollutants including smoke and carbon monoxide, comprises an alarm circuit including a detector for radiation and/or pollutants and an audible alarm emitting device. A power supply circuit, connectable to an external AC power supply, supplies power to the alarm circuit. A controller operates the power supply circuit in a first mode of operation in which it supplies current to the alarm circuit at a first power level less than that required to energize the audible alarm emitting device and, in response to the detection of radiation and/or pollutants, operates the power supply in a second mode of operation in which it supplies current to the alarm circuit at a second power level sufficient to energize the audible alarm emitting device.

The present invention relates to a system for testing the availability of a detector for detecting smoke. More specifically, the present invention relates to a detector with a testing unit arranged to detect whether the detector has been covered, such that it is unable to perform its function as a smoke detector.

An ion chamber provides a current representative of its characteristics as affected by external conditions, e.g., clean air or smoke. A direct current (DC) voltage is applied to the ion chamber at a first polarity and the resulting current through the ion chamber and parasitic leakage current is measured at the first polarity, then the DC voltage is applied to the ion chamber at a second polarity opposite the first polarity, and the resulting current through the ion chamber and parasitic leakage current is measured at the second polarity. Since substantially no current flows through the ion chamber at the second polarity, the common mode parasitic leakage current contribution may be removed from the total current measurement by subtracting the current measured at the second polarity from the current measured at the first polarity, resulting in just the current through the ion chamber.

An ion chamber provides a current representative of its characteristics as affected by external conditions, e.g., clean air or smoke. A direct current (DC) voltage is applied to the ion chamber at a first polarity and the resulting current through the ion chamber and parasitic leakage current is measured at the first polarity, then the DC voltage is applied to the ion chamber at a second polarity opposite the first polarity, and the resulting current through the ion chamber and parasitic leakage current is measured at the second polarity. Since substantially no current flows through the ion chamber at the second polarity, the common mode parasitic leakage current contribution may be removed from the total current measurement by subtracting the current measured at the second polarity from the current measured at the first polarity, resulting in just the current through the ion chamber.

A method of mounting and dismounting a smoke alarm from a supporting element mounted to an overhead surface; said method including the steps of, inserting an elongate implement into an opening provided in a body of the smoke alarm, and applying a force via the elongate implement so as to detach the body of the smoke alarm from the supporting element, and wherein the elongate implement is applied by a user standing on a floor surface below the overhead surface.

A method of mounting and dismounting a smoke alarm from a supporting element mounted to an overhead surface; said method including the steps of, inserting an elongate implement into an opening provided in a body of the smoke alarm, and applying a force via the elongate implement so as to detach the body of the smoke alarm from the supporting element, and wherein the elongate implement is applied by a user standing on a floor surface below the overhead surface.