Smoke detectors vs Smoke alarms

[shortcircuit1]

I know the difference between smoke alarms and smoke detectors but i am looking at NFPA 72 and they have requirements for the smoke alarms but when it comes to smoke detectors they are not clear as to where they are required.And i am scratching my head :blink: as to do we need to install smoke detectors or smoke alarms in our units?

 

[gadfly56]

I know the difference between smoke alarms and smoke detectors but i am looking at NFPA 72 and they have requirements for the smoke alarms but when it comes to smoke detectors they are not clear as to where they are required.And i am scratching my head :blink: as to do we need to install smoke detectors or smoke alarms in our units?

Smoke alarms are generally for residential use. Smoke detectors are for commercial locations. Then you have hotels, which could be a mixture of both, depending on the contract documents, local requirements, and the designer's general inclination.

So, when you say "units", what are you referring to?

 

[infinity]

Smoke detectors are initiation devices and when they detect smoke they signal an alarm system, do not have an integral alarm like smoke alarms.

 

[shortcircuit1]

Smoke alarms are generally for residential use. Smoke detectors are for commercial locations. Then you have hotels, which could be a mixture of both, depending on the contract documents, local requirements, and the designer's general inclination.

So, when you say "units", what are you referring to?

I was referring to residential units.Yes i see requirements for smoke alarms but none for smoke detectors in dwelling units in NFPA 72.

 

[shortcircuit1]

Smoke detectors are initiation devices and when they detect smoke they signal an alarm system, do not have an integral alarm like smoke alarms.

Do the smoke alarms have to be tied up to FACP?And if i am not wrong the power supply for the smoke alarms is same as the smoke detectors which is one commercial source of power supply and second can be a generator source or battery backup.Am i right on this?

 

[gadfly56]

Do the smoke alarms have to be tied up to FACP?And if i am not wrong the power supply for the smoke alarms is same as the smoke detectors which is one commercial source of power supply and second can be a generator source or battery backup.Am i right on this?

Interconnected smoke alarms operate at 120VAC with a 9VDC backup. You don't hook them up to a fire alarm control panel (FACP). FACP's fall under UL864 and initiating devices placed on their indicating device circuits (IDC's) or signal line circuit's (SLC's) must be listed for use with that panel. Smoke alarms are not supervised while smoke detectors are.

I was referring to residential units.Yes i see requirements for smoke alarms but none for smoke detectors in dwelling units in NFPA 72.

You didn't look very hard. See chapter 29 in NFPA 72-2013.

 

[shortcircuit1]

Interconnected smoke alarms operate at 120VAC with a 9VDC backup. You don't hook them up to a fire alarm control panel (FACP). FACP's fall under UL864 and initiating devices placed on their indicating device circuits (IDC's) or signal line circuit's (SLC's) must be listed for use with that panel. Smoke alarms are not supervised while smoke detectors are.



You didn't look very hard. See chapter 29 in NFPA 72-2013.

If you are referring to 29.5.1 required detection that is for smoke alarms and 29.8.3.4 is for specific location requirements(Both smoke detectors and smoke alarms).Are there any more other than these two references?

 

[jumper]

I was referring to residential units.Yes i see requirements for smoke alarms but none for smoke detectors in dwelling units in NFPA 72.

It is in the IRC.

 

[gadfly56]

If you are referring to 29.5.1 required detection that is for smoke alarms and 29.8.3.4 is for specific location requirements(Both smoke detectors and smoke alarms).Are there any more other than these two references?

Sure. 29.5.2.1.2 for notification requirements that points to 29.3.6, 29.6.2 for power to household fire alarm systems, 29.8.2 for interconnection, etc. They didn't separate the two types of detection into distinct categories. You have to read the whole chapter to get the full picture.

 

[gadfly56]

It is in the IRC.

Actually, also in 29.5. The very first and only sentence, in fact.

29.5 Detection and Notification. The use of fire alarm system
smoke detectors and notification appliances shall be permitted
to meet the fire-warning requirements for smoke alarms
specified in 29.5.1.

 

[shortcircuit1]

Sure. 29.5.2.1.2 for notification requirements that points to 29.3.6, 29.6.2 for power to household fire alarm systems, 29.8.2 for interconnection, etc. They didn't separate the two types of detection into distinct categories. You have to read the whole chapter to get the full picture.

I am sorry but in the sections you pointed out those refer to the notification requirements,power supplies and interconnection.Am i missing something here?Like for the installation of smoke alarms they are pretty clear but when it comes to the smoke detectors it is little vague.

 

[shortcircuit1]

Actually, also in 29.5. The very first and only sentence, in fact.

29.5 Detection and Notification. The use of fire alarm system
smoke detectors and notification appliances shall be permitted
to meet the fire-warning requirements for smoke alarms
specified in 29.5.1.

Yes!So if i interpret that sentence correctly you can use the same rules for placing the smoke detectors as well as smoke alarms?

 

[jumper]

Yes!So if i interpret that sentence correctly you can use the same rules for placing the smoke detectors as well as smoke alarms?

Gadfly knows 72, I am just familiar with IRC. It says locations are the same.

https://www.bcnv.org/DocumentCenter/Home/View/55

 

[gadfly56]

Yes!So if i interpret that sentence correctly you can use the same rules for placing the smoke detectors as well as smoke alarms?

Yes.

 

[shortcircuit1]

Yes.

Thanks!Is there any requirements for placement of strobes(Horn or Audio/Visual)in dwelling units?I generally place them one inside the bedroom and one outside in the living area to have coverage.

 

[gadfly56]

Thanks!Is there any requirements for placement of strobes(Horn or Audio/Visual)in dwelling units?I generally place them one inside the bedroom and one outside in the living area to have coverage.

If you are using separate notification appliances you'll need one in each bedroom as well as outside the sleeping area. It doesn't actually say that, but you have to have a certain db level at the pillow. If you have a horn in the hallway right outside the bedroom door and you close the door, you'll never meet that minimum level even with the horn at 99 db. I know, I've done surveys with that exact setup.

In addition, following the smoke alarm requirements, you'll need a notification device on each level. Where it gets really tricky is if you incorporate a CO detector into the system. Now you need to find a way to generate a temporal 4 signal as well as temporal 3. The easiest way to get all that done is with sounder bases for the detectors.

 

[shortcircuit1]

If you are using separate notification appliances you'll need one in each bedroom as well as outside the sleeping area. It doesn't actually say that, but you have to have a certain db level at the pillow. If you have a horn in the hallway right outside the bedroom door and you close the door, you'll never meet that minimum level even with the horn at 99 db. I know, I've done surveys with that exact setup.

In addition, following the smoke alarm requirements, you'll need a notification device on each level. Where it gets really tricky is if you incorporate a CO detector into the system. Now you need to find a way to generate a temporal 4 signal as well as temporal 3. The easiest way to get all that done is with sounder bases for the detectors.

I get the part where we have to have 75db requirement for pillow level and like as you pointed out it would be hard to get that db if you close the door.But is there any code reference for one outside the sleeping unit?I know its a common sense to have one outside the sleeping area like smoke alarms but i want to see if it says anywhere in the code.

 

[jumper]

I get the part where we have to have 75db requirement for pillow level and like as you pointed out it would be hard to get that db if you close the door.But is there any code reference for one outside the sleeping unit?I know its a common sense to have one outside the sleeping area like smoke alarms but i want to see if it says anywhere in the code.

While you are waiting for Gadfly, I did find this:

The NFPA 72 requirement for sleeping rooms is either a minimum of 75 dBA or 15 dB over the average ambient sound level, whichever is greater. It is important to use a sound level meter to ensure the minimum sound levels have been achieved. NFPA 72 requires sound level meters to meet the requirements of ANSI S1.4a, Specifications for Sound Level Meters, Type 2 requirements. This basically means the meter must be able to be calibrated. m

https://www.sdmmag.com/articles/85224-horns-strobes-clarifying-code-requirements

Not exactly what you asked, no code section.

Seems like a reputable source.

 

[gadfly56]

I get the part where we have to have 75db requirement for pillow level and like as you pointed out it would be hard to get that db if you close the door.But is there any code reference for one outside the sleeping unit?I know its a common sense to have one outside the sleeping area like smoke alarms but i want to see if it says anywhere in the code.

29.5.1.1* Where required by other governing laws, codes, or
standards for a specific type of occupancy, approved single and
multiple-station smoke alarms shall be installed as follows:
(1)*In all sleeping rooms and guest rooms
(2)*Outside of each separate dwelling unit sleeping area,
within 21 ft (6.4 m) of any door to a sleeping room, with
the distance measured along a path of travel

As I keep saying, you have to read the whole section.

 

[shortcircuit1]

29.5.1.1* Where required by other governing laws, codes, or
standards for a specific type of occupancy, approved single and
multiple-station smoke alarms shall be installed as follows:
(1)*In all sleeping rooms and guest rooms
(2)*Outside of each separate dwelling unit sleeping area,
within 21 ft (6.4 m) of any door to a sleeping room, with
the distance measured along a path of travel

As I keep saying, you have to read the whole section.

I was referring to system fire alarm strobes not the local smoke alrms like if someone in the building pulls a pull station then the occupants in the building should be notified through strobes in their dwelling units.We need a 75db in the sleeping area as per NFPA 72 but do we require one outside the sleeping area per NFPA?