I

Ingress Protection

An international rating system which classifies the ability of an item of equipment to withstand ingress from either solid particles or liquids. Otherwise known as the 'IP' rating.

Insulator

A material which will not pass electrical current except at high voltages.

Interface

Apparatus used to monitor or control parts of a fire protection system or external equipment.

To find out more, visit the Apollo Interfaces page.

Interrupt

A signal placed on the communications protocol by a manual call point during polling of another device. The purpose of the interrupt is to minimise the time delay between operation of a manual call point and sounding of the alarm. Apollo patented.

Ionisation Detector (Ionization - US)

A smoke detector incorporating a radioactive isotope to ionise air and cause a small current flow between an inner (reference) and outer (smoke) chamber. Smoke entering the outer chamber causes an imbalance in the current flow which in turn causes the detector to change to the alarm state.

To find out more, click here.

Ionization Detector

See above.

Intrinsically Safe (IS)

A range of devices that have been specifically developed for use in hazardous areas where an explosive mixture of air and gas or vapour is or may be present. These areas typically include petroleum and chemical engineering plants and factories processing and storing gases, solvents and other volatile substances.

IS devices must be approved by a body such as BASEEFA/ATEX.
To find out more, visit our intrinsic safety page.

Isolator

A device which senses and isolates a short-circuit on an Apollo analogue addressable loop.