[Bldg-sim] Automatic Lighting Shutoff MandatoryProvisionQuestion

Bishop, Bill wbishop at pathfinder-ea.com
Wed Oct 6 06:56:06 PDT 2010

I agree with Nick's explanation to Jaigath, below. A 10% LPD credit can
be taken in spaces that have occupancy sensors, except where occupancy
sensors are required (classrooms etc. per It would make no
sense to allow energy savings only for spaces that have both time clock
and occupancy controls, since a space with both controls would provide
no additional energy savings over an occupancy sensor alone.
I also agree with Nick's comment to Rohini. Leave the baseline LPD alone
(turning lights off during unoccupied hours using the same schedule in
baseline and proposed) and take the 10% credit in the proposed where
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From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Jeremy
Sent: Wednesday, October 06, 2010 12:52 AM
To: Nick Caton; R B
Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Automatic Lighting Shutoff
We just had a pretty in-depth discussion on this internally also - local
implementations of the code (for example, Chicago Building Code) have
added some confusion.  To add to what Nick said, the credits in table
G3.2 are only referenced in the lighting requirements in Table G3.1 and
are specifically listed for use in the proposed model for controls that
are not already required by the mandatory provisions of Section 9.  I've
always found it ironic that a Section G3.2 doesn't exist even though a
Table G3.2 does...but I digress...here is where we arrived internally:
Section 9.4.1 has 4 main parts - Whole building control, individual
space control, exterior lighting control and additional mandatory
- requires an automatic whole building control capable of
shutting off lighting (with override capabilities allowed) for the
entire building based on either (a) time clock signal, (b) occupancy
sensors, or (c) some other control signal (like a BMS).  This applies to
all buildings over 5,000 SF.
- requires an individual control for all spaces, either
manual or automatic.  For specific space types, automatic controls are
required: classrooms (except shop classrooms, laboratory classrooms, and
preschool - 12th grade classrooms), conference/meeting rooms, and
employee lunch and break rooms UNLESS those rooms have multiscene
control in which case they are also exempt from the automatic
requirement.  All other spaces are not required to have automatic
controls and can have either manual or automatic controls.  In addition,
those spaces where automatic controls are mandatory are NOT required to
be connected to other automatic lighting shutoff controls (i.e. the
whole building controls required by
- requires photocell or astronomical time clock control
of site lighting (with some nuances, but this is a safe simplification
of the requirements).
- requires a number of specialty lighting installations
to have controls - most applicable to LEED is the requirement for all
task lighting to have an individual control.
The way I simplified this for our engineers is the following: any and
all spaces will have 2 levels of code-required control.  The first will
comply with and the second will comply with  As an
example, for a typical private office our engineers have been using wall
devices that have an occ sensor with a manual control.  If that is the
only controls that cover the private office, then the occ sensor
complies with and the manual switch complies with; no
credit from Table G3.2 would be allowed since both control methods are
required by 9.4.1.  Now, if there is a time clock in the building and
the private office were connected to the time clock with the same wall
device the situation would be different: the time clock would comply
with and the manual switch would comply with leaving the
occupancy sensor as an additional control, eligible in Table G3.2 for a
10% LPD credit against the PROPOSED LPD factors.  For a classroom in a
community center, if the lighting is setup for multiple purposes and the
space is on the building time clock, then you just have compliance with and respectively.  If you put in an occ sensor (some
control logic required due to the multiscene) then you can take credit
for that sensor in Table G3.2.
I'm curious what you two think of this interpretation?
We even went so far in our discussion to look literally at the way is worded and I believe that since the word "either" does not
imply mixed compliance then any given building must comply entirely with
one of the three options, not a mix of two.  Say a time clock for common
spaces with occ sensors for tenant leased space, for example, would not
comply with the most strict reading of the code.  That is quite literal,
but I've had code reviewers who have read other codes that literally
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From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Nick Caton
Sent: Tuesday, October 05, 2010 10:40 AM
To: R B
Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Automatic Lighting Shutoff Mandatory
While it's a minor point, I'd only caution that my "hard and fast rule"
is pretty much a directly from Table G3.1.6:  "No automatic lighting
controls ... shall be modeled in the baseline building design..."  That
said, if I were a reviewer I wouldn't have a problem with your approach.
While modeling occ. sensors in both cases would help the EUI of the
proposed model, not modeling occ sensors in both cases will mean your
baseline and proposed  HVAC systems have to deal with extra internal
loads, so presuming you have a better HVAC system in the proposed model,
I'd intuitively assume if anything a classroom-heavy school/university
might do better to not model occ. sensors in each model... I guess if
the results bear it out, go with the flow though =).
25501 west valley parkway
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From: R B [mailto:slv3sat at gmail.com] 
Sent: Tuesday, October 05, 2010 10:23 AM
To: Nick Caton
Cc: Jaigath Chandraprakash; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Automatic Lighting Shutoff Mandatory Provision
I actually take the credit for occ. sensor in both the baseline and
proposed case for such spaces that have a mandatory requirement for
occupancy sensor (e.g. classroom). The advantage is your total energy
consumption is slightly less, so when you are in border line cases where
you are ever so slightly less than the required percentage points for
the next level of points it helps. Much more advantageous to do it this
way when you are doing a school/university building.

Rohini Brahme, Ph.D, LEED AP
Building energy analysis, tool development, and training
Dallas/Fort Worth, TX 
On Tue, Oct 5, 2010 at 9:06 AM, Nick Caton <ncaton at smithboucher.com>
The hard and fast rule I follow is that baseline LPD's are never to be
messed with.  Any and all credit taken for lighting controls is a
deduction of LPD (or sufficiently documented schedule adjustment, I
suppose) in the proposed case. 
It can get confusing, but in specific spaces (i.e. classrooms),
may require occ. sensors.  In such a case, I don't take a credit in the
baseline (see hard/fast rule above), but instead remove the credit
otherwise taken for that space in the proposed case.    

25501 west valley parkway
olathe ks 66061
direct 913 344.0036
fax 913 345.0617
Check out our new web-site @ www.smithboucher.com
From: Jaigath Chandraprakash [mailto:cjaigath at yahoo.com] 
Sent: Monday, October 04, 2010 8:32 PM
To: Nick Caton; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Automatic Lighting Shutoff Mandatory Provision
Thank you very much Nick. I really appreciate your help on this.
I really got confused with this when I got a commnet recently saying
that the "baseline case per section were not modeled" and was
asked to revised the baseline. So I ended up with no savings. This is in
conflict with Table G3.1.6 that you have pointed out which says that No
automatic lighting controls shall be modeled in the baseline building
Does it mean that I am wrong when I applied also 10% savings to my
baseline? This is where I got confused since also mentions
occupant sensor that shall turn lighting off within 30 mins of occupant
leaving the space. 

From: Nick Caton <ncaton at smithboucher.com>
To: Jaigath Chandraprakash <cjaigath at yahoo.com>; 
bldg-sim at lists.onebuilding.org
Sent: Mon, October 4, 2010 10:38:08 PM
Subject: RE: [Bldg-sim] Automatic Lighting Shutoff Mandatory Provision
Appendix G allows us to take credit for automatic controls in addition
to (beyond) what's required in 9.4.1 for minimum compliance.  One of the
options here is to have programmable (time-of-day) shutoff for interior
lighting circuits, and you can infer from between Table G3.1 and G3.2 of
Appendix G that baseline models are taken to feature only such timeclock
controls for automatic shutoff.  Further, it's taken that the lighting
scheduling being kept identical between the proposed and baseline
adequately reflects the minimum requirements, so you aren't supposed to
try to explicitly model the programmable shutoff.  
If you have occupancy sensors throughout a building which only requires
programmable shutoff, that's an example of having automatic controls
beyond what 9.4.1 requires - and you'd get to take 10% off your proposed
LPD in all spaces where such short-term shutoff isn't already required
(per following section
Note Table G3.2 also has a corresponding distinction between building
smaller than and larger than 5,000ft2 - offering more credit for
buildings using a means of automatic shutoff where no such controls are
even minimally required.
Error! Filename not specified.
25501 west valley parkway
olathe ks 66061
direct 913 344.0036
fax 913 345.0617
Check out our new web-site @ www.smithboucher.com 
From: bldg-sim-bounces at lists.onebuilding.org [mailto:
bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Jaigath
Sent: Monday, October 04, 2010 9:01 AM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Automatic Lighting Shutoff Mandatory Provision
Hello All,
I am confused on the mandatory provision which states that
building larger than 5000 ft2 shall have automatic control device. Does
it mean that mid-rise and high rise building cannot claim for credit in
occupancy sensors shown in Table G3.2 because their GFA is more than
5000 ft2 and only small office can claim for this credit? I am sure I am
not interpreting this section correct since from what I read, other
modelers  are claiming for savings for buildings with more than 5000 ft2
area for occupancy sensors even if mandatory requirements states that
this is required which means baseline building will also have occupancy
Can someone correct me on this? 
Thank you,
C. Jaigath 

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