DAQ-2025-001018

Small Source Registration

DAQE-EN161610002-25

{{$d1 }}

Jolene Clark
Utah State University
416 East Innovation Avenue
North Logan, UT 84341
[e-mail]

Dear Ms. Clark:

Re: Request for Evaluation of Compliance with Rule R307-401-9, UAC: Small Source Exemption
Project Fee Code: N161610002

On January 30, 2025, the Division of Air Quality (DAQ) received your request for a small source
exemption for Utah State University’s Space Dynamics Laboratory. The source is located at 416 East
Innovation Avenue, North Logan, in Cache County. The eight (8) buildings at the facility with emergency
engines and various buildings with exempt natural gas combustion equipment are considered a single
source. DAQ has determined the small source exemption applies to the source, as long as the equipment
and associated processes operate as specified in the registration request. Specifically, the source shall not
run each emergency engine on site for more than 30 hours per year in non-emergency situations.

The small source exemption does not exempt a source from complying with other applicable federal,
state, and local regulations and the current Utah Administrative Code. Based on the emissions that you
submitted to DAQ with your registration request, Utah State University’s Space Dynamics Laboratory is
not required to obtain an approval order under R307-401. If you change your operation such that there is
an increase in emissions, we recommend that you notify us, as an approval order may be required.

As authorized by the Utah Legislature, the fee for issuing this small source exemption is a one-time filing
fee in addition to the actual time spent by the review engineer and all other staff on the project. Payment
should be sent to DAQ upon receipt of the invoice.
195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144820 • Salt Lake City, UT 84114-4820
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah

SPENCER J. COX
Governor
DEIDRE HENDERSON
Lieutenant Governor

Department of
Environmental Quality

Kimberly D. Shelley
Executive Director

DIVISION OF AIR QUALITY
Bryce C. Bird
Director

" / 2 / 6 Ú Ü Û Ù Û Þ
DAQE-EN161610002-25
Page 2
Thank you for registering your source with the DAQ. If you have any additional questions, please contact
Dungan Adams at [phone] or [e-mail].

Sincerely,

Bryce C. Bird
Director

{{$s }}

Alan D. Humpherys, Manager
New Source Review Section

BCB:ADH:DA:jg

{{#d1=date1_es_:signer1:date:format(date, "mmmm d, yyyy")}} {{#s=Sig_es_:signer1:signature}}
195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144820 • Salt Lake City, UT 84114-4820
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper

DAQE-MN161930001-25

M E M O R A N D U M
TO: 16193: Utah State University- Airport Hangar Space Dynamics Laboratory
(N161930001)

THROUGH: Alan Humpherys, Minor NSR Manager – Air Quality
FROM: Dungan Adams, Environmental Engineer – Air Quality
DATE: February 11, 2025
SUBJECT: Mailing Address for Small Source Exemption Letter (DAQE-EN16193001-24)
Updated
On January 15, 2025, Utah State University’s Space Dynamics Laboratory requested that the
mailing address of their small source exemption (SSE) letter (DAQE-EN16193001-24 dated
January 17, 2024) be updated from 8315 Old Main Hill, Logan, UT 84322-8315 to 416 East
Innovation Avenue, North Logan, UT 84341. The incorrect address listed in the SSE letter is the
mailing address for Utah State University’s campus. The updated address is the mailing address
for Utah State University’s Space Dynamics Laboratory. The Utah Division of Air Quality
(DAQ) has updated the mailing address in their records and will incorporate this address change
if a new SSE is issued to this source in the future.
State of Utah

SPENCER J. COX Governor
DEIDRE HENDERSON Lieutenant Governor

Department of
Environmental Quality
Kimberly D. Shelley Executive Director
DIVISION OF AIR QUALITY Bryce C. Bird Director
Dungan Adams <[e-mail]>
USU Space Dynamics Laboratory Permitting Question
13 messages
Dungan Adams <[e-mail]>Tue, Nov 12, 2024 at 2:12 PM
To: [e-mail]
Hi Jolene,
My name is Dungan and I work in the minor new source review permitting section at the Utah Division of Air Quality
(DAQ). My manager assigned me to help answer a permitting question that was originally asked to John Persons. From
my understanding, USU Space Dynamics Laboratory currently holds a small source exemption (SSE), and you reached
out to see if you could reduce the operation of emergency generators from 100 hours per year to 30 hours per year in
order to remain below the threshold which requires an Approval Order.
The operation reduction you have outlined is possible, but I would need to see data/justification that supports the 30 hours
per year. I would also need to issue a new SSE that includes language limiting emergency generator operation to 30
hours per year.
UAC Code Rule R307-401-10 lists source category exemptions, one of which is natural gas fuel burning equipment rated
less than 5 MMBtu/hr. DAQ guidance states that exempt equipment does not disqualify a source from registering for a
SSE. Basically, if the equipment in the new building is natural gas fuel burning equipment rated less than 5 MMBtu/hr then
you can keep your SSE status even if the emissions from the equipment bump you over the 5 tons per year (tpy)
threshold.
I think there is a very good chance the Space Dynamics Laboratory can remain below the 5 tpy threshold with the
addition of another building, but since you don't have the equipment information for the building my recommendation
would be to hold off on any SSE updates until you do. When you do get information about the new building, please let me
know and I can confirm that the laboratory remains below all applicable thresholds.
Let me know if that sounds good and if you have any questions.
Thanks,
Dungan
--

Dungan Adams
Environmental Engineer | Minor NSR Section
M: [phone]
airquality.utah.gov
Jolene Clark <[e-mail]>Tue, Nov 12, 2024 at 3:13 PM
To: Dungan Adams <[e-mail]>
Hi Dungan,

2/5/25, 11:11 AM State of Utah Mail - USU Space Dynamics Laboratory Permitting Question
https://mail.google.com/mail/u/0/?ik=c52f18613a&view=pt&search=all&permthid=thread-a:r8412651044987740747&simpl=msg-a:r-301627769261226…1/7
I appreciate you following up with me. This is some very good informaon. I will see what informaon I can find regarding our new
building and get back with you.

Thanks again,

Jolene Clark
Safety Administrator
416 East Innovation Avenue
North Logan, Utah 84341
Office: 435-713-3836
Cell: 435-799-7512
[Quoted text hidden]
Jolene Clark <[e-mail]>Wed, Dec 18, 2024 at 11:33 AM
To: Dungan Adams <[e-mail]>
Hi Dungan,

I’m reaching out to follow up on the natural gas equipment in the new building we’ll soon be moving in to. The building has seven
roof top units and one water heater with the BTU rangs as follows:

Water heater – 40,000 BTU
RTU #1 – 120,000
RTU #2 – 100,000
RTU #3 – 200,000
RTU #4 200,000
RTU #5 – 100,000
RTU#6 – 150,000
RTU #7 – 200,000

Addionally, I want to let you know about a development that may affect our exempon status. We’re currently doing construcon
on one of our buildings and will soon be adding a new emergency generator. I believe the generator will have a capacity of 500 kw
and a 1,700 gal tank.

2/5/25, 11:11 AM State of Utah Mail - USU Space Dynamics Laboratory Permitting Question
https://mail.google.com/mail/u/0/?ik=c52f18613a&view=pt&search=all&permthid=thread-a:r8412651044987740747&simpl=msg-a:r-301627769261226…2/7
Regarding our emissions calculaons, I’m sll hoping to use our actual run me data instead of the default 100 hours per year. You
menoned that you would need data/jusficaon supporng our runme in order to do this. Could you clarify what specific data
you require? Would data from our monthly inspecon records be sufficient to meet your requirements? During our monthly
inspecons we record generator runmes. Currently our generators are exercised for 30 minutes weekly, though we plan to reduce
this to 30 minutes every two week. In terms of actual usage, power outages are infrequent. For example: In October, one generator
ran for 1.5 hours (including the weekly exercise me). In November, it ran for 5.8 hours, which included both exercise me and a
brief power outage. Even with the power outage, the annual run me is sll well below 100 hours. On average our generator
runmes are typically between 1.5 and 2.5 hours per month, and this will soon decrease with the reduced exercise schedule.

Please let me know how we should proceed with this and whether you believe we sll qualify for the SSE. If addional informaon is
needed to move forward, please let me know. If you think it would be helpful, I’m happy to arrange a Zoom meeng to discuss our
status in more detail. I look forward to your guidance and next steps.

Best regards,
[Quoted text hidden]
Dungan Adams <[e-mail]>Thu, Dec 19, 2024 at 2:53 PM
To: Jolene Clark <[e-mail]>
Jolene,
Thanks for following up.
The natural gas equipment in the new building is all rated <5 MMBtu/hr. As stated in my initial email, UAC Code Rule
R307-401-10 lists natural gas fuel burning equipment rated less than 5 MMBtu/hr as exempt equipment. Since all of the
natural gas equipment is <5 MMBtu/hr, none of those emissions will be included in threshold determination. The new 500
kW engine will need to be included in emission calculations. If the generators are exercised only 30 minutes weekly, I am
good to use 30 hours of operation per year for emission estimates. I don't need any further justification, but I will need to
re-issue a Small Source Exemption to include a statement that says all emergency generators on site will each run up to
30 hours per year. In periods of maintenance or power outage, emergency generators can run as much as necessary and
that operation would not count towards the 30 hours per year.
Before we move forward with re-issuing a small source exemption, I would like to get some more information about the
facility. You have mentioned there are multiple buildings and emergency generators. Could you list the number of
buildings and the emitting equipment (emergency engines, combustion equipment, etc.) in each building?
Thanks,
Dungan
[Quoted text hidden]
Jolene Clark <[e-mail]>Fri, Dec 20, 2024 at 3:09 PM
To: Dungan Adams <[e-mail]>
Dungan,

That is great news. Thank you for leng us know we can use 30 hours of operaon. I will make sure to get you a list of our buildings
and eming equipment. With the holiday break, it will most likely be aer the first part of the year.

Thanks again,
Jolene
[Quoted text hidden]
2/5/25, 11:11 AM State of Utah Mail - USU Space Dynamics Laboratory Permitting Question
https://mail.google.com/mail/u/0/?ik=c52f18613a&view=pt&search=all&permthid=thread-a:r8412651044987740747&simpl=msg-a:r-301627769261226…3/7
Jolene Clark <[e-mail]>Tue, Jan 7, 2025 at 3:17 PM
To: Dungan Adams <[e-mail]>
Dungan,

I am following up to provide the list of our buildings and eming equipment. We have a total of 16 buildings, eight of which have
emergency generators. I’ve also included a list of our natural gas eming equipment for each building. While you menoned that
equipment under 5 MMBtu is exempt from the calculaons, I’ve included it for your reference, should you need it. Please let me
know if you need addional informaon.

Thank you,

Jolene
[Quoted text hidden]
Emission Sources.docx
17K
Dungan Adams <[e-mail]>Tue, Jan 14, 2025 at 11:47 AM
To: Jolene Clark <[e-mail]>
Hi Jolene,
Thanks for sending this over.
From what I see in the document, all of the individual natural gas equipment in all of your buildings is less than <
5MMBtu/hr. This equipment is exempt from the requirement to obtain an Approval Order (AO) and emissions from the
equipment would not count towards small source exemption determination.
After looking at a map of the space dynamics laboratories, I think all of the SDL buildings would be considered a single
source. I believe they are all under common control (i.e. all operated by the SDL), belong to the same industrial grouping,
and are contiguous or within close proximity to each other. If this is the case and you agree with this determination, the
DAQ can issue a single Small Source Exemption (SSE) for all of the SDL buildings.
I have attached a spreadsheet which estimates the emissions from each engine assuming 30 hours of operation per year.
Based on emissions, this combined source would qualify for a SSE. If you feel 30 hours of operation per year for each
engine is a conservative estimate for maintenance, exercise, testing, .etc, please confirm. A sentence in the SSE letter will
need to be included saying something like the following: "The source shall not operate each emergency engine on site for
more than 30 hours per rolling 12-month period during non-emergency situations."
Let me know if you have any questions and if you would like to move forward with a single SSE for the SDL buildings.
Thanks,
Dungan
[Quoted text hidden]
USU SDL Emergency Engine Calculations.xlsx
161K
Jolene Clark <[e-mail]>Wed, Jan 15, 2025 at 4:14 PM
To: Dungan Adams <[e-mail]>
Hi Dungan,
2/5/25, 11:11 AM State of Utah Mail - USU Space Dynamics Laboratory Permitting Question
https://mail.google.com/mail/u/0/?ik=c52f18613a&view=pt&search=all&permthid=thread-a:r8412651044987740747&simpl=msg-a:r-301627769261226…4/7

I le you a phone message this morning, but will follow up with an email. Yes, let’s move forward with a single SSE for our Logan
site. The 30 hours of operaon per year is more than adequate to cover any exercising, maintenance, etc. For your reference I have
aached the previous SSE that we were issued for this locaon. In addion, I aached the SSE for our airport hangar. The return
address is not correct. I don’t know if this is a problem that should be fixed, but I thought I’d bring it to your aenon. Instead of
8315 Old Main Hill, it should have our 416 E Innovation Ave address. I think we got mixed up with USU.

Thank you for sending the spreadsheet of your esmates. I am familiar with the emission factor and the reference tables, but I have
a few quesons (below). This is just for my own understanding to make sure I’m looking at the informaon correctly.
I see that you used 750 kw to calculate the emission totals. Which emission total do you look at when determining if we fall
below the 5 ton/yr? Is it NOx only, or do you look at others as well?
Since we have 8 generators that vary in size, for your esmaon did you just assume they were all 750 kw and mes that
emission factor by 8?
I’ve never calculated HAPs before. Is that something I should be doing on our end?

Thanks for everything.
[Quoted text hidden]
2 attachments
DAQE-EN161610001-24.pdf
155K
DAQE-EN161930001-24.pdf
155K
Dungan Adams <[e-mail]>Thu, Jan 16, 2025 at 9:14 AM
To: Jolene Clark <[e-mail]>
Hi Jolene,
I have attached a screenshot of what I see on my end regarding the spreadsheet I sent on Tuesday. At the bottom of the
page there are nine tabs, the first summing the total PTE for all buildings, and the next eight calculating the
individual emissions from each engine. If you can see these, please check and make sure that the engine ratings are
correct. If you can't see these tabs, let me know.
Here is the link to the Small Source Exemption (SSE) Application. The application goes over the specific eligibility criteria
for a SSE. The emissions units would be the emergency engines and the natural gas boilers <5 MMBtu/hr. You can put
N/A for pollution control equipment since I don't believe any is used for the small engines and boilers. You can upload the
emission calculations I sent once you have reviewed them.
I will follow up with my manager about updating the mailing addresses/physical locations and get back to you. In the mean
time, let me know if you have any questions.
Thanks,
Dungan
[Quoted text hidden]
2/5/25, 11:11 AM State of Utah Mail - USU Space Dynamics Laboratory Permitting Question
https://mail.google.com/mail/u/0/?ik=c52f18613a&view=pt&search=all&permthid=thread-a:r8412651044987740747&simpl=msg-a:r-301627769261226…5/7
Screenshot 2025-01-16 084729.png
76K
Jolene Clark <[e-mail]>Thu, Jan 16, 2025 at 4:44 PM
To: Dungan Adams <[e-mail]>
Hi Dungan,

The spreadsheet you sent me did have the tabs at the boom. I don’t know how I missed that before. I verified that all the engine
rangs are correct and everything looks great. The only small item that is a lile off is the sulfur content in our fuel is 10% instead of
15%, but since the SO2 is well below the NOx, that point is not important.

Thanks for all your help and answering my quesons.
[Quoted text hidden]
Dungan Adams <[e-mail]>Fri, Jan 17, 2025 at 9:35 AM
To: Jolene Clark <[e-mail]>
Hi Jolene,
Awesome, I am glad everything looks good. When you fill out the SSE application, you can attach the spreadsheet as
your emission calculations. In this case, since the total site-wide SO2 emissions are estimated to be less than 0.00 tons
per year, I don't think changing the sulfur content to 10% is necessary.
In regards to the address issue you discovered on the existing SSE letter, can you clarify if the mailing address is
incorrect or if physical location is incorrect? If it is a mailing address issue, then I can make that change and send you an
email confirmation that the address has been updated in our system. If the physical location is incorrect, then you will
need to submit a new SSE application. I think the letter in question is DAQE-EN161930001-24 (attached above), and it
looks like the mailing address should be corrected to 416 E Innovation Ave. If that is the only issue, I can get that
corrected on the DAQ's end right away.
Thanks,
Dungan
[Quoted text hidden]
Jolene Clark <[e-mail]>Fri, Jan 17, 2025 at 10:28 AM
To: Dungan Adams <[e-mail]>
Hi Dungan,

Yes, you’re right, it’s the mailing address that is incorrect. The site address is correct. Instead of the Old Main Hill address, we need
it to be corrected to the 416 E Innovation Ave address. Thanks for geng that fixed for us.

2/5/25, 11:11 AM State of Utah Mail - USU Space Dynamics Laboratory Permitting Question
https://mail.google.com/mail/u/0/?ik=c52f18613a&view=pt&search=all&permthid=thread-a:r8412651044987740747&simpl=msg-a:r-301627769261226…6/7
Regarding the SSE applicaon, is this the correct form? https://utahgov.co1.qualtrics.com/jfe/form/SV_3t4JtgzRudum7l3

Thanks,
[Quoted text hidden]
Dungan Adams <[e-mail]>Fri, Jan 17, 2025 at 1:23 PM
To: Jolene Clark <[e-mail]>
Yes, that is the correct form.
Thanks,
Dungan
[Quoted text hidden]
2/5/25, 11:11 AM State of Utah Mail - USU Space Dynamics Laboratory Permitting Question
https://mail.google.com/mail/u/0/?ik=c52f18613a&view=pt&search=all&permthid=thread-a:r8412651044987740747&simpl=msg-a:r-301627769261226…7/7