• Welcome to The Building Code Forum

    Your premier resource for building code knowledge.

    This forum remains free to the public thanks to the generous support of our Sawhorse Members and Corporate Sponsors. Their contributions help keep this community thriving and accessible.

    Want enhanced access to expert discussions and exclusive features? Learn more about the benefits here.

    Ready to upgrade? Log in and upgrade now.

Occupant Sensors-C405.2.1 Clarification

VAC

VAC

SAWHORSE
Joined
Jul 10, 2022
Messages
100
Location
Florida's Treasure Coast
Understanding the spaces where the occupancy sensors are required is clear.
Here is the question
Does the 300SF limit apply to any of the spaces listed or it is just for spaces that are not mentioned.
I always thought the 300SF limit applied to any and all spaces (few exceptions like open offices/warehouses)
Am I misinterpreting the requirement/code?
Thanks!
 
VAC said:
Understanding the spaces where the occupancy sensors are required is clear.
Here is the question
Does the 300SF limit apply to any of the spaces listed or it is just for spaces that are not mentioned.
I always thought the 300SF limit applied to any and all spaces (few exceptions like open offices/warehouses)
Am I misinterpreting the requirement/code?
Thanks!
Click to expand...
The less than 300SF is for OTHER occupancies not listed. So all of the areas one through 12 which includes other spaces 300SF or less. it is a catch all. For example, an IT room with computer equipment that is less than 300SF must have an occupancy sensor. The 300SF limit does not apply to the other 11 examples, just the "other spaces"

C405.2.1Occupant sensor controls.​

Occupant sensor controls shall be installed to control lights in the following space types:
  1. 1.Classrooms/lecture/training rooms.
  2. 2.Conference/meeting/multipurpose rooms.
  3. 3.Copy/print rooms.
  4. 4.Lounges.
  5. 5.Employee lunch and break rooms.
  6. 6.Private offices.
  7. 7.Restrooms.
  8. 8.Storage rooms.
  9. 9.Janitorial closets.
  10. 10.Locker rooms.
  11. 11.Other spaces 300 square feet (28 m2) or less that are enclosed by floor-to-ceiling height partitions.
  12. 12.Warehouses.
 
jar546 said:
The less than 300SF is for OTHER occupancies not listed. So all of the areas one through 12 which includes other spaces 300SF or less. it is a catch all. For example, an IT room with computer equipment that is less than 300SF must have an occupancy sensor. The 300SF limit does not apply to the other 11 examples, just the "other spaces"

C405.2.1Occupant sensor controls.​

Occupant sensor controls shall be installed to control lights in the following space types:
  1. 1.Classrooms/lecture/training rooms.
  2. 2.Conference/meeting/multipurpose rooms.
  3. 3.Copy/print rooms.
  4. 4.Lounges.
  5. 5.Employee lunch and break rooms.
  6. 6.Private offices.
  7. 7.Restrooms.
  8. 8.Storage rooms.
  9. 9.Janitorial closets.
  10. 10.Locker rooms.
  11. 11.Other spaces 300 square feet (28 m2) or less that are enclosed by floor-to-ceiling height partitions.
  12. 12.Warehouses.
Click to expand...
Thank you! I think I get it.
So a Conference room that is 400 SF will still require a sensor because the limit doesn't apply to that occupancy.
But an IT room (not listed) would be subject to the limit and not require one if it's 400 SF.
Did I get that right?
 
VAC said:
Thank you! I think I get it.
So a Conference room that is 400 SF will still require a sensor because the limit doesn't apply to that occupancy.
But an IT room (not listed) would be subject to the limit and not require one if it's 400 SF.
Did I get that right?
Click to expand...
That is the way I read and interpret it.
 
  • Like
Reactions: VAC
VAC said:
Not sure anyone is omitting OS.
Simply discussing the 300SF limitation and how to apply it. Since this is beyond what I normally do, it wasn't clear to me. Thanks!
Click to expand...
I was simply putting what the plan review comment is.....Everyone tries to omit them here...
 
And don't forget that if they omit OS, they put in a timeclock...

C405.2.2 Time-switch controls. Each area of the building
that is not provided with occupant sensor controls
complying with Section C405.2.1.1 shall be provided
with time-switch controls complying with Section
C405.2.2.1.
 
steveray said:
And don't forget that if they omit OS, they put in a timeclock...

C405.2.2 Time-switch controls. Each area of the building
that is not provided with occupant sensor controls
complying with Section C405.2.1.1 shall be provided
with time-switch controls complying with Section
C405.2.2.1.
Click to expand...
Yes! Thank you for pointing that out
 
# ~ # ~ #

IMO, ...the OC's are well intentioned devices to limit the use
of electrical power usage when not needed, however, when
installed in some office settings, they will turn off the lights
while people are still working in that office ( i.e. - can you
say nuisance lighting controls ? ).

Are today's lighting sensors manufactured with timing
controls on them, or has a system been devised yet to
control lighting throughout a defined period similar to the
HVAC System controls ?

# ~ # ~ #
 
# ~ # ~ #

I think ** steveray ** answered my question whilest I was typing my response.

& ( ) & ( ) &
 
Reviving my thread from 2 years ago... you can see how often I do this :)

A waiting area is not listed as part of the 12 spaces (above.)

Does it fall under this exception?

Exception: Full automatic-on controls shall be permitted to control lighting in public corridors, stairways, restrooms, primary building entrance areas and lobbies, and areas where manual-on operation would endanger the safety or security of the room or building occupants.

The waiting area I'm working on is in a small office. There is a vestibule and the waiting area is right outside a greeters window. (kind like you see in medical practices)

I don't have an OS in the vestibule but the waiting is technically an intervening space and used as egress to reach the exit.

Conversely, A restroom is listed as part of the 12 spaces (above), yet, it's also mentioned on the exception.
I just mention this because I find it confusing as well. I have the OS in the restrooms, but is the exception also saying I can skip them? -I won't, but looking for your expertise.

Any thoughts on these?
(For the record, I am not trying to avoid getting out of installing OS, just trying to get clarity from those who do this all day long)

Thank you!
 
VAC said:
Reviving my thread from 2 years ago... you can see how often I do this :)

A waiting area is not listed as part of the 12 spaces (above.)

Does it fall under this exception?

Exception: Full automatic-on controls shall be permitted to control lighting in public corridors, stairways, restrooms, primary building entrance areas and lobbies, and areas where manual-on operation would endanger the safety or security of the room or building occupants.

The waiting area I'm working on is in a small office. There is a vestibule and the waiting area is right outside a greeters window. (kind like you see in medical practices)

I don't have an OS in the vestibule but the waiting is technically an intervening space and used as egress to reach the exit.

Conversely, A restroom is listed as part of the 12 spaces (above), yet, it's also mentioned on the exception.
I just mention this because I find it confusing as well. I have the OS in the restrooms, but is the exception also saying I can skip them? -I won't, but looking for your expertise.

Any thoughts on these?
(For the record, I am not trying to avoid getting out of installing OS, just trying to get clarity from those who do this all day long)

Thank you!
Click to expand...
That section is merely about control operation....For full on vs. half on...Sorta

1753115820284.png

1753115913006.png
 
You must log in or register to reply here.
Back
Top