• Smoke Alarm: A standalone device that detects smoke, usually 9-volt battery and/or 120 volts alternating current. Used in residential occupancies to alert you of possible fire mainly when you are sleeping. Note the human senses can detect fire faster than any smoke alarm can when you are awake and are in the same room.
• Smoke Detector: A device that is part of a system that detects the physical characteristics of smoke and emits a signal in response to a fire alarm panel. The detector is the decision-making component to activate the fire alarm system.
• Smoke Sensor: A device that is part of a system that senses the physical characteristics of smoke and transmits a value to a fire alarm panel. The fire alarm panel is the decision-making component to activate the fire alarm system.
• Ionization Detectors/Sensor: Are generally more responsive to flaming fires. Ionization-type smoke detectors/sensors have a small amount of radioactive material between two electrically charged plates, which ionize the air and causes current to flow between the plates. When smoke enters the chamber, it disrupts the flow of ions, thus reducing the flow of current and activating the alarm.
• Photoelectric Detectors/Sensor: Are generally more responsive to fires that begin with a long period of smoldering. Photoelectric-type detectors/sensors aim a light source into a sensing chamber at an angle away from the sensor. Smoke enters the chamber, reflecting light onto the light sensor triggering the alarm. 
• Smoke Alarms/Detectors/Sensors Installation Location: On the ceiling, wall mount within 12 inches of the ceiling. When mounting on a sloped ceiling they shall be mounted near the highest peak.

• Smoke Alarm: A standalone device that detects smoke, usually 9-volt battery and/or 120 volts alternating current. Used in residential occupancies to alert you of possible fire mainly when you are sleeping. Note the human senses can detect fire faster than any smoke alarm can when you are awake and are in the same room.
• Smoke Detector: A device that is part of a system that detects the physical characteristics of smoke and emits a signal in response to a fire alarm panel. The detector is the decision-making component to activate the fire alarm system.
• Smoke Sensor: A device that is part of a system that senses the physical characteristics of smoke and transmits a value to a fire alarm panel. The fire alarm panel is the decision-making component to activate the fire alarm system.
• Ionization Detectors/Sensor: Are generally more responsive to flaming fires. Ionization-type smoke detectors/sensors have a small amount of radioactive material between two electrically charged plates, which ionize the air and causes current to flow between the plates. When smoke enters the chamber, it disrupts the flow of ions, thus reducing the flow of current and activating the alarm.
• Photoelectric Detectors/Sensor: Are generally more responsive to fires that begin with a long period of smoldering. Photoelectric-type detectors/sensors aim a light source into a sensing chamber at an angle away from the sensor. Smoke enters the chamber, reflecting light onto the light sensor triggering the alarm. 
• Smoke Alarms/Detectors/Sensors Installation Location: On the ceiling, wall mount within 12 inches of the ceiling. When mounting on a sloped ceiling they shall be mounted near the highest point of the ceiling.
• Smoke Alarms How Many and Where: You shall have one in every bedroom, one outside of every bedroom and one on every floor.
  Example 1: Three bedrooms all connected by one hallway; you shall have one in the hallway. You shall have a total of four smoke alarms.
  Example 2: Two bedrooms connected by a hallway and a third bedroom on the opposite side of the house. You shall have a total of five smoke alarms.
  Example 3: Three bedrooms all on the second floor with a common hallway and a family room in the basement. You shall have a total of six smoke alarms.
• Smoke Alarm are NOT meant to be install business occupancies. Business occupancies the standard is to install smoke detectors or smoke sensors connected to a fire alarm control panel with a monitoring service. The Building Code and Fire Code determine if a fire alarm system is required.

updated 2-September-2020