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BARNARD HQ
SANITARY SEWER & WATER DEMAND REPORT
Project No. 22285
Barnard Headquarters
Bozeman, Montana
March 27, 2023
March 27, 2023
Project No. 22285
SANITARY SEWER & WATER DEMAND REPORT
BARNARD HQ
BOZEMAN, MONTANA
SITE NARRATIVE
The purpose of this report is to summarize the design capacity and demands of the proposed
sanitary sewer and water service installations associated with the Barnard HQ project in
Bozeman, Montana. The water and sanitary service lines will connect to existing service stubs
south of Royal Wolf Way.
SEWER
The proposed building has two proposed sanitary sewer services exiting the building and includes
the installation of approximately 415-feet of 6-inch PVC sewer lines. The two 6-inch services will
tie-in to existing 6-inch sanitary sewer service stubs located on the south side of Royal Wolf
Way.
Capacity calculations were conducted per the City of Bozeman Design Standards and
Specifications Policy dated March 2004, updated May 2017 and Circular DEQ 4. Capacity
calculations are in Appendix A. The 6-inch sewer service capacity at 75-percent full is 268-gal/min
using the minimum pipe slope of 0.02 ft/ft.
The “Nelson Meadows Subdivision Water and Wastewater Report” dated February 2018 by
Morrison-Majerle estimated the total wastewater generated for the entire subdivision based on
the M-1 zoning at 960 gallons per acre per day. The proposed Barnard HQ parcel is 9.75 acres,
so utilizing the same 960 gallons per acre per day criteria, results in an estimated sanitary sewer
demand for Barnard HQ of 9,360 gal/day. The peaking factor assumed in the subdivision report
was 3.87. Using this peaking factor results in a peak hour flow of 36,223.2 gal/day or 25.2 gal/min.
The peak hour flow of 25.2 gal/min is the maximum allowable sewer design capacity for the
Barnard HQ project.
The project area is zoned M-1, Manufacturing. It is assumed that there will be approximately 356
employees at the proposed office building. Per Table 3.1-1 in Circular DEQ 4 for an office building,
the typical wastewater flow is 13 gpd/person.
P:22285_Utility_Design_Report 2 (03/27/2023)RPE/br
The typical wastewater flow for the building is as follows:
Sanitary Sewer Average Demand = 13 gpd/person * 356 employees = 4,628 gpd
Peak flow calculations for the proposed sanitary sewer pipes were completed to find the overall
peak flow in the 6-inch sewer service exiting the development. The average daily flow exiting the
development was estimated at 3.21 gal/min. A peaking factor of 3.87 was then applied for a peak
hourly flow rate of 12.44 gal/min. An infiltration flowrate of 1.02 gal/min was then used to
calculate a total peak hourly flow rate with infiltration of 13.45 gal/min, which is significantly less
than the 6-inch capacity of 268 gal/min stated above. The estimated wastewater flow is also less
than the wastewater projection for the Nelson Meadows subdivision, 25.2 gal/min, and therefore
has been designed to adequately serve the proposed Barnard HQ development.
WATER
The proposed water system consists of approximately 360-feet of new 4-inch diameter water
service and approximately 345-feet of new 6-inch diameter fire service. The proposed 4-inch and
6-inch diameter services will tie-in to existing 4-inch and 6-inch service stubs which are connected
to the existing 8-inch water main in Royal Wolf Way.
Morrison-Maeirle calculated the peak hour demand based on fixture counts to be 115 gpm, see
Appendix B. The City of Bozeman adjusted the PRV set points feeding the Nelson Meadows
subdivision to provide higher pressures throughout the subdivision. After the PRV adjustment,
we received updated fire flow test data for the two (2) existing fire hydrants closest to the site.
Based on these adjustments, there is adequate pressure to service the general domestic demand
and fire service based on the incoming system pressure (115 psi) in the water main in Royal Wolf
Way, see Appendix C.
A total flow of 1,990 gpm (1,875 gpm fire flow demand and 115 gpm peak hour demand) was
used to assume the total fire flow demand. Based on this demand, the residual pressure at the
existing hydrant in Royal Wolf Way is 103.2 psi which is well above the required 20-psi minimum
per the 2012 IFC and City of Bozeman requirements, see Appendix C. Therefore, the existing
water mains within Royal Wolf Way can adequately serve the proposed Barnard HQ
development.
CONCLUSION
Based on the assumptions provided above, the proposed 6-inch sanitary sewer service, 4-inch
water service, and 6-inch fire service installations will provide the required capacity for the
proposed Barnard HQ in the Nelson Meadows Subdivision. Please contact Bobby Egeberg, PE for
any questions pertaining to this report by email, begeberg@sandersonstewart.com or by phone
406-922-4308.
APPENDIX A Sanitary Sewer Demand CalculationsBarnard HQ Sanitary Sewer & Water Demand Report
22285
Project: 22285 Barnard HQ
Date: 3/27/2023
Capacity Calclulations
6" Pipe Flowing Full Capacity 0.80 cfs
6" Pipe Flowing Full Capacity 357 gal/min
Q/Qfill @ 75% full, 0.75 per nomograph
Capacity @ 75% full 268 gal/min
City of Bozeman Sanitary Sewer System Design Criteria
DESIGNATION (DEQ Circular 4 Table 3-1.1)People Demand
Office (13gpd/person)356 4628 gal/day
Total Demand 4628 gal/day
3.21 gal/min
Peaking Factor (per Nelson Meadows Subdivision)3.87
Peak Hourly Flow 12.44 gal/min
Infiltration at 150 gal/acre/day 1463 gal/day
Infiltration gal/min 1.02 gal/min
Total Peak Hourly Flow plus Infiltration 13.45 gal/min
Result
Q/Qfull based on peak hour 0.05
Percent Full for 6" From Nomograph at peak hour 18%
Service Area
APPENDIX B Water Demand Calculations Barnard HQ Sanitary Sewer & Water Demand Report
22285
memo
Page 1
TO: City of Bozeman
FROM: Joe Hughes, PE, Morrison Maierle, Inc.
DATE: 01/10/2023
RE: Barnard Office Building Water Demand Calculations
Urgent For Review Please Comment Please Reply For Your Use
The table below shows the summary of fixtures being serviced in the new Barnard Office building.
Fixture Fixture Units, Supply (Drainage) Quantity WSFU DFU
Drinking Fountain 0.5 (0.5) 6 3 3
Floor Drain, 2” - - (2.0) 44 0 88
Floor Sink, 4” - - (8.0) 3 0 24
Hose Bibb 2.5 (- -) 1 2.5 0
Hose Bibb (each additional) 1.0 (- -) 7 7.0 0
Lavatory (Single) 1.0 (1.0) 43 (3) 43 3
Lavatory (Group of 2-3) - - (2.0) 16 - - 32
Mop Sink 3.0 (3.0) 4 12 12
Shower 2.0 (2.0) 9 18 18
Sink (Domestic) 1.5 (2.0) 8 12 16
Urinal 4.0 (2.0) 5 20 10
Water Closet (Flush Valve) 5.0 (4.0) 47 235 188
Total 352.5 394
Note: WSFU values per 2021 UPC Appendix A – Table A 103.1. DFU values per 2021 UPC Ch. 7, Table 702.1.
Per Chart A 103.1 in Appendix A of the 2021 UPC, 343 water supply fixture units are roughly
equivalent to 115 GPM. Again per Appendix A, this requires a 3” domestic water service.
Per UPC 702.1 Table 702.2(2), the expected peak sanitary waste demand is approximately
2955 GPM. This clearly is an overestimation and is not realistic. It is our opinion that the
sanitary flow should more closely match the domestic water supply demand of 115 GPM.
- END -
Barnard HQ Sewer & Water Demand Report
22285 APPENDIX C Fire Flow Test Analysis
CITY OF BOZEMAN
Fire Flow Request Form
PHONE (406) 582-3200 FAX (406) 582-3201
The results of the fire flow information that you requested are as follows: Royal Wolf Way
(Nelson Meadows)
HD #3056 Static – 115PSI, Residual – 108PSI HD#3055 Pitot –80PSI flowing 1500 GPM on a
2.5” nozzle. Fire Flow test performed on 2/10/2023.
If you have questions or need further information feel free to email.
Data Disclaimer: Water distribution information is calculated using hydraulic modeling software and is subject to
variation. Actual field conditions may vary. This information provided to the requestor for evaluation purposes only,
without warranty of any kind, including, but not limited to any expressed or implied warranty arising by contract,
stature, or law. In no event regardless of cause, shall the City be liable for any direct, indirect, special, punitive or
consequential damages of any kind whether such damages arise under contract, tort, strict liability or inequity.
Barnard HQ
Project No. 22285
March 27, 2023
Fire Flow Test Analysis:
Discharge at Pf Pressure at Fire
Static Pressure (Ps) 115 psi (Qf)2 Condition (Pf)
Residual Pressure During Test (Pt)108 psi 6,806 0
Pitot Pressure During Test 80 psi 6,139 20
Discharge During Test (Qf)1501 gpm 5,403 40
4,570 60
3,580 80
2,266 100
1,990 103.2
0 115
Water System Hydraulic Calculations
Hydrant Data from Royal Wolf Way
y = -2E-06x2 - 0.003x + 117.56
R² = 1
0
20
40
60
80
100
120
0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000Pressure (psi)Flow (gpm)
Pressure vs Flow