Using an external portable Test Lamp
is the best and only sure method to perform a fully functional test.

Most optical fire and flame detectors have automatic internal self-tests for checking its viewing window lens cleanliness. These detectors include UV, UV/IR, Multi-Spectrum UV/IR/VIS, Multi-spectral IR, Single Band IR, Dual Band IR, Triple Band IR, Multi-Spectrum Triple IR, QuadBand Triple IR, etc. However, these detectors´ automatic tests do not constitute a fully functional "end to end" detector test. The automatic self-tests only partially check the operational readiness of a detector since the actual alarm outputs are not activated.

Manually using a Test Lamp is the only non-hazardous and safe method to test any flame or fire detector’s sensors, internal electronics and its alarm activation software, viewing window lens cleanliness, terminal wiring integrity, actual relay activation, and the proper functionality of any other outputs that are used.  Also, since most detectors are installed in a fire protection alarm system, using a Test Lamp is the only practical method to test the complete fire alarm system, ensuring all the system wiring and cabling and system control panel(s) are properly installed.

Using an external Test Lamp also verifies that the detector has an unobstructed, clear view of the fire threat area. Since all electro-optical radiant energy fire and flame detectors are line-of-sight devices, they must be properly positioned and oriented with an unobstructed view of the threat area so that they can "see" in order to detect flames/fires. A physical obstruction in the detector’s partial or full field of view can seriously compromise the integrity of the fire detection ("blind") and protection system such as:

1. Such things as paint overspray, masking tape, storage boxes, vehicles, and hanging garments such as hats, coats, tarp, etc. physically covering the detector’s window viewing lens.
   
   
2. Detector mounting bracket breakage, failure, or misalignment where detector is improperly oriented (aimed) at the fire threat area. Like a human being watching for a fire, the detector must be "looking" in the right direction of the fire and not be "staring" at the ground or in the wrong direction. Since most optical fire and flame detectors are used in industrial applications, vibration, physical impact, maintenance, cleaning, etc. can cause improper detector orientation resulting in unprotected detection zone even though the detector is reporting a successful automatic self-test to the Fire Alarm Panel. This kind of "false security" can be disastrous if an actual fire occurred in this unprotected area.
   
   
3. Storage boxes, crates, equipment, or air ducts or pipes placed or installed after fire protection system commissioning that are in the detector’s direct field of view of the threat area. Again, a detector with automatic self-test will report to the Fire Alarm Panel that it is working properly even though it is unable to alarm to a fire occurring in its detection coverage area.

Using an external Test Lamp verifies an optical fire or flame detector´s viewing window lens cleanliness and its internal electronic operation similar to an internal automatic detector self-test. However, importantly, it will also functionally test its critical alarm outputs, whether relay activation, 4-20mA alarm output, RS-485 digital data output including ModBus, etc. is used, the detector and system’s wiring terminals, cabling and its splicing connections, Fire Alarm Panel functionality, proper alarm notification, and, if desired, actual suppression release, etc.

It must be noted and emphasized: If an actual suppression release (i.e., high or low pressure carbon dioxide, water, water mist, FM200, AFFF, etc.) is NOT desired, this action MUST BE DISABLED at the Fire Alarm Releasing Panel.

To comply with NFPA standards (and AHJ requirements), "end to end" testing of Fire Protection Alarm Systems, including detectors, should be performed periodically. Many Plant Managers of high valued assets and facilities, including Life Safety, mandate quarterly "end to end" testing of their entire Fire Protection Systems using an external Test Lamp.