Detector VS Alarm

Since I started in this biz, I have used the term “Smoke Detector” and later “CO Detector” in my reports and discussions. And then yesterday, a fellow inspector and smart guy pointed out to me, that I am using the wrong term.

He referenced the 2021 IRC code commentary volumes. Most of what I see and all of what I report on are actually alarms, and not detectors.

Ripped from the internet summary of the IRC commentary:

  • A smoke alarm is a device that has both a sensor to monitor for smoke and a speaker to alert people to a fire. It is usually used in homes or individual apartments.
  • A smoke detector is a device that has only a sensor to monitor for smoke and is connected to a fire suppression system or a building-wide fire alarm system. It is usually used in office, industrial, health care, apartment, etc., buildings.

So, I am amending my reports and mentally adjusting my verbal terms to be more accurate. It’s a small thing, but I find the distinction interesting.


Seems accurate to me. The whole “detector” thing has always seemed half-way.

1 Like

Yes smoke alarm is the proper term if it has it’s own integral signaling device. A smoke detector like a heat detector or a pull station is an initiation device that will signal a FA control panel to initiate an alarm.


I agree with you completely!

I have attempted many times over the years to ‘enlighten’ others as to this very subject…
(One of many threads below)…


All smoke alarms are smoke detectors, but not all smoke detectors are smoke alarms.

Put another way…

A smoke detector could refer to either a smoke alarm or a smoke detector, whereas a smoke alarm can only refer to a device with a built in alarm.

I will continue to “report on the absence of smoke detectors as per my state’s SOP(InterNACHI SOP has the same requirement).


Of course before any alarm is sounded the gas of interest must be ‘detected.’ Some will argue semantics all day long despite knowing exactly to what you are referring.



The inspector shall inspect:

A. the service drop;
B. the overhead service conductors and attachment point;
C. the service head, gooseneck and drip loops;
D. the service mast, service conduit and raceway;
E. the electric meter and base;
F. service-entrance conductors;
G. the main service disconnect;
H. panelboards and over-current protection devices (circuit breakers and fuses);
I. service grounding and bonding;
J. a representative number of switches, lighting fixtures and receptacles, including receptacles observed and deemed to be arc-fault circuit interrupter (AFCI)-protected using the AFCI test button, where possible;
K. all ground-fault circuit interrupter receptacles and circuit breakers observed and deemed to be GFCIs using a GFCI tester, where possible; and
L. for the presence of smoke and carbon monoxide detectors.


Not according to the IRC, as I pointed out in my original post. Your comment would be semantically on target, if the IRC had not defined the differences.
As for your state’s SoP, if it requires you to use the term “detector” for an alarm, then that settles it for you.
The InterNACHI SoP arguably has some wiggle room in it for using the more accurate terminology since most houses not only, do not have detectors, but most states require alarms as described in the IRC.


You should follow the SOP but it’s too bad that they’re using the incorrect terminology.


They are refered to as alarms in the Ohio SOP.


At least half of the confusion lies within the state laws, alarm manufacturer’s websites, and SOP’s.

Example in my state it is titled “Illinois Smoke Detector Act”.

Then the Illinois State Fire Marshall calls it Illinois Smoke Alarm Law

Then from the NFPA website: “What kind of smoke alarm (smoke detector) should I buy?”

Home Depot, Lowe’s and most if not all of the major smoke alarms / detectors websites have the same wording. They’ll start off with the title being smoke detector. Then the first sentence will say smoke alarm.

And Illinois SOP:
3) Report on the presence of solid conductor aluminum branch circuit wiring and on the absence of carbon monoxide and smoke DETECTORS.


I always use “Smoke Detectors/Alarms should be…” in my narratives. Seems to cover both angles and I’ve never had anyone correct me.


That’s the way I address them in my reports also Thomas. :+1:


I love refining my skill and knowledge with the small things.


Maybe the InterNACHI SOP can be changed to reflect more accuracy regarding the above definitions? @bgromicko1 @gromicko



says right on them


Not to be argumentative, but it’s kind of in the definition:

A smoke alarm is…both a sensor(detector) to monitor for smoke and a speaker(alarm) to alert people to a fire.
A smoke detector is…only a sensor(detector) to monitor for smoke and is connected to a fire suppression system or a building-wide fire alarm system.

IMO, absent a definition from either InterNACHI SOP or Indiana SOP, the spirit of the requirement is to report the absence of a fire alert system, whether it be a series of interconnected smoke alarm devices, or a Fire Alarm System with a centralized fire alarm control unit and remote smoke detector devices.

Curious. if you encountered a Fire Alarm System with remote smoke detectors, would you be feel compelled to report the absence of smoke alarms?


Please pardon me for chiming in. A fire alarm system with integrated smoke detectors satisfies the alarm portion of the statement. Provided the fire alarm system has audible alerts (horns/bells); which it should.

1 Like

Oh, I agree. It satisfies the spirit of the SOP requirement.

1 Like

On a side note, I wish they would add strobes to these devices for a visual alert.