Smoke Detectors in University

[dema]

I have been told by vendors in the past that various fire alarm equipment is required here and there where I cannot find any reference to the requirement in the code. I am particularly musing about the need for a smoke detector at the top of a stairwell and the top of an elevator shaft.

Is there a requirement for either anywhere in the national codes, and if so, would you please give me the reference?

I am interested in any reference to these smoke detectors being required in any type of construction.

And while I'm at it. NFPA 72 states that a visible alarm notification device is required in public and common areas, and the only definition I can find for that is "Use by more than one person". Really? A two person office is a common area? I've been putting them in. But is there anything that defines common area differently?

 

[mgookin]

A University can have many different occupancy classifications in it. Academic Hall (usually Group B), Dorms (Group R), Physical Plant (Industrial), Library & Dining Halls (Assembly), etc.

What building are you in?

 

[GrayHair]

And why do I need one of

And why do I need one of

NFPA 72 includes sections of other codes by reference. For example, in 72 there are no specifics on whether a duct detector is required or where it should be located; 72 references 90A and it's there you'll find the specifics. 90B is also referenced but contains no requirements for fire alarms. Whether or not a fire alarm system is even required comes from 101 and as mgookin pointed out, different occupancies. Building design may bring unfamiliar requirements into play as can the design of the life safety system itself. Selecting a particular method can change what is usually a option to a requirement. Smoke control (NFPA 92) would be a good example.

My usual disclaimer: I've been retired for several years, have not kept up with the latest codes and local requirements can change everything.

 

[ron]

To know where the requirements for smoke detector locations being required, means you need access to several codes. In most jurisdictions, the Building Code Section 907 offers most of the information. Then elevator code A17.1 for shaft detection and Mechanical code (generally IMC) for duct detection. Then NFPA 72 tells you how to install the stuff.

For example
907.2.13.1.1 Area smoke detection.
Area smoke detectors shall be provided in accordance with this section. Smoke detectors shall be connected to an automatic fire alarm system. The activation of any detector required by this section shall activate the emergency voice/alarm communication system in accordance with Section 907.5.2.2. In addition to smoke detectors required by Sections 907.2.1 through 907.2.10, smoke detectors shall be located as follows:1. In each mechanical equipment, electrical, transformer, telephone equipment or similar room which is not provided with sprinkler protection.2. In each elevator machine room and in elevator lobbies.

 

[dema]

Classrooms Type B

Classrooms Type B

So, it doesn't sound like you know of a reference to a stairwell requirement? Anywhere?

Thank you for your references.

 

[mgookin]

So, it doesn't sound like you know of a reference to a stairwell requirement? Anywhere?

Thank you for your references.

Group B stairwells do not need smoke detectors.

But don't take my word. Ask the fire official for your project.

 

[gadfly56]

There doesn't appear to be any prescriptive requirement for smoke detectors being at the top of stairwells. However, stairwells are frequently so constructed as to prevent the accumulation of smoke at any point short of the top of the stairwell. As long as the stairwell is less than about 4 stories, the logical place for the detector is at the top of the stairwell. For stairwells above 4 stories, you probably want to place detectors on every 4th story. The reason for this is that as smoke rises in the stairwell, it cools. You most likely won't find any fire hot enough to drive the smoke much higher than 40 feet, and maybe a good deal less, as the smoke is likely to be fairly cool before it gets into the stairwell.

As far as the elevator shaft, they are required if the hoistway is sprinklered. They're forbidden otherwise, unless they are for hoistway smoke control.

 

[ron]

As far as the elevator shaft, they are required if the hoistway is sprinklered. They're forbidden otherwise, unless they are for hoistway smoke control.

A17.1 requires smoke detectors to activate elevator recall. A heat detector is often in place at the top of the shaft next to the smoke detector to shunt trip the elevator power if it is sprinklered.

 

[dema]

Thank you

Thank you

I appreciate the input. Finding information is one thing. Verifying that a claim does not exist is something else entirely. How in the world does one know she has looked everywhere?

 

[GoldDigger]

I appreciate the input. Finding information is one thing. Verifying that a claim does not exist is something else entirely. How in the world does one know she has looked everywhere?

Usually, by finding a complete list of applicable codes and then word searching the entirety of each one instead of relying on a TOC or index.
Not easy, but possible. Local amendments can make it more difficult.

 

[ron]

I appreciate the input. Finding information is one thing. Verifying that a claim does not exist is something else entirely. How in the world does one know she has looked everywhere?

Unfortunately, this is why they keep us old people around. Job security is to spread out the requirements to multiple disparate codes so you need to ask.

 

[gadfly56]

A17.1 requires smoke detectors to activate elevator recall. A heat detector is often in place at the top of the shaft next to the smoke detector to shunt trip the elevator power if it is sprinklered.

These could be the elevator lobby smoke detectors or the elevator machine room smoke detector(s). Further to my point:

NFPA 72-2007

6.16.3.6 Smoke detectors shall not be installed in unsprin-
klered elevator hoistways unless they are installed to activate
the elevator hoistway smoke relief equipment.

 

[ron]

These could be the elevator lobby smoke detectors or the elevator machine room smoke detector(s). Further to my point:

NFPA 72-2007

6.16.3.6 Smoke detectors shall not be installed in unsprin-
klered elevator hoistways unless they are installed to activate
the elevator hoistway smoke relief equipment.

It seems with the advent of machine-roomless elevators, the hoist mechanism is at the top of the shaft and it has been considered the elevator machine room for machine-roomless elevators, by some AHJ's

 

[gadfly56]

It seems with the advent of machine-roomless elevators, the hoist mechanism is at the top of the shaft and it has been considered the elevator machine room for machine-roomless elevators, by some AHJ's

You raise an interesting point. We did a retrofit for a tenant adding sprinklers to a building that was used for a charter school. The elevator machine room was at the top, with the hoist mechanism in the room. There was a trap in the floor to access the hoistway proper. Since the hoistway was not sealed away from the machine room, was everything in the hoistway? In this case, because sprinklers were installed we had a heat and smoke under the floor, and another pair at the ceiling. Thinking about it now makes my head hurt. What if there were no sprinklers?