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Sundance Springs Comm Lot 2
Water Design Report
Revised July 27, 2022
Project Background
•2 buildings
•1.31 acres
•Commercial use (mixed office, food service, and retail)
•Zoning designation is B-1 (neighborhood commercial)
Design Flow
•From DSSP V.A “Water Distribution Lines Design Criteria”, the design flow shall be based on a
maximum hour to average day ratio of 2.3:1 for an average daily usage of 170 GPD per person.
•From DSSP V.A, “for non-residential flows an equivalent population shall be calculated”.
Equivalent population is calculated based on estimated wastewater flow rate:
o For B-1 zoning, estimated wastewater flow is 1,000 gallons/acre/day (DSSP Table V-1)
plus 150 gallons/acre/day for estimated infiltration losses. 1,150 * 1.31 acres = 1506.5
GPD.
o 1506.5 GPD is used to estimate equivalent population for domestic water demand
calculations.
o Per COB Engineering, estimated wastewater flow is 64.4 GPD/person.
o 1506.5 GPD / 64.4 GPD/persons = 24 persons equivalent population.
•170 GPD/person * 24 persons = 4,080 GPD daily flow for the estimated equivalent population.
•2.3:1 average day ratio: 4,080 * 2.3 = 9,384 GPD = 6.5 GPM water service demand
•28 GPM for landscaping demands based on fixture count analysis.
•6.5 GPM plus 28 GPM = 34.5 GPM for two buildings of equivalent size and use.
•34.5 / 2 = 17.25 GPM non-fire flow service line demand per building
•ISO (Insurance Services Offices) criteria for fire flow demand = 1500 GPM
Water Main Specifications
•Main line – 8-inch diameter Ductile Iron Pipe (DIP), 321’
•Water main shall be constructed using fittings at 11.25, 22.5, and 90-degree angles.
•Water main shall be placed a minimum of 10’ from sewer main.
COB Standard Drawings
•MPW 02660-1 Thrust Blocking for Water Main Fittings
•MPW 02660-2 Water and Sewer Main Separation
•COB 02660-3 Thrust Blocking for Water main Valves
•COB 02660-7 Typical Blowoff Valve
•COB 02660-6 Water Service Line
•COB 02660-10 Typical Valve/Tee Restraint
•COB 02660-12 Water Service Line
•COB 02660-13 Standard Fire Service Line Installation
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• COB 02660-16 Water and Sewer Main and Services Location Standards
• COB 020660-17 Water Service Interior Clearances
Main Size
A line serving more than one building is designated a water main. The water main for Sundance Springs
Comm Lot 2 has water service demands of 34.5 GPM, and a fire flow demand of 1500 GPM. Head Loss
calculations indicate that 321’ of = 8’’ DIP with a C of 130 and a flow rate of 1534.5 GPM will have an
actual head loss of 5.72 psi and a velocity of 9.8 ft/s. COB requires that the velocity not exceed 15 ft/s.
COB requires that the minimum diameter for any new main is 8 inches unless specific approval in writing
Is obtained from the COB. Water main pressure at the connection point is assumed to be 30 psi based
on the residual pressure at hydrant 1075 in the COB network. Working residual water pressure is
assumed to be 30 psi -6.8 psi = ~23.2 psi.
Main Extensions
The new main will be tapped from a 12” COB water main beneath Little Horse Drive. The proposed
dead-end main is approximately 321 feet in length and shall end with a 2” blow-off valve. A 6” main
extension stub exists onto the property but will be capped.
Services Lines
Each of the two buildings shall have two service lines, with one for domestic water service and the other
designated for fire-flow demand. An additional service line connection will provide landscaping flows to
the berm along South 3rd Ave. Service lines are sized so as not to exceed 10 feet/sec velocity as
calculated by the fixture unit method as specific in the Uniform Plumbing Code. Using the AWWA water
demand for fixtures calculation, the fixture demand is 17 GPM/building.
Standard service lines shall be 1” type “K” copper to accommodate 17.25 GPM per building. Fire flow
service lines shall be 4’’ ductile iron pipe to accommodate fire flow for building sprinklers. The
landscaping service line shall be 1.5” type “K” copper. Backflow prevention devices will be installed as
required by the Water Superintendent.
No service line shall be extended into the buildings until an “Application for Service” has been
completed and a Plumbing Permit has been obtained from the Building Department.
Building fire sprinkler demand estimate:
• Occupied square footage (main and upper floor) for each building is approximately 6000 SF
• Fire sprinkler head cover = 200 SF (Architectural Tool Box)
• Output per sprinkler head = 20-45 gpm (Summit Fire and Security Bozeman)
• 6000 SF/165 SF = 30 heads * 30 gpm = 1080 gpm (lower flow range)
o The Hazen-Williams calculation for a 4’’ water pipe with a flow of 1080 gpm indicates a
velocity of 27.6 ft/s, meeting the NFPA 24 standard of greater than 10 ft/s for fire
service lines.
• NCRRS Fire Flow calculator = 1500 gpm (higher flow range)
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o The Hazen-Williams calculation for a 4’’ water pipe with a flow of 1500 gpm indicates a
velocity of 38.3 ft/s, meeting the NFPA 24 standard of greater than 10 ft/s for fire
service lines.
Valves: One eight-inch gate valve is proposed at the connection to the existing 12-inch water main in
Little Horse Drive.
Hydrants: No hydrants are proposed on the site. Two existing hydrants on the corners of Little Horse
Drive and Ellis View Loop with South 3rd Ave provide coverage for the lot with both buildings entirely
within 400’ of one or both hydrants per IFC 2018 specifications.
Air Relief: Air relief is provided by the 2” blowoff valve.
Pressure Reducing Valves: Pressure reduction valves are not required for these service connections.
Attachments: (1) ISO Fire Flow Calculation
(2) Hazen-Williams Calculations
(3) Fixture Count
07/27/2022
Page 1/3
NFF = (Ci)(Oi)(Xi+Pi)
C=18F(Ai)^0.5
Address:
Project Name:Occupancy Type:Commercial
Construction Type:Number of Stories:2
STEP 1 Take the area, which is 100% sq. ft. of the first floor plus the following percentage
of the total area of the other floors.
First Floor Area in Sq. Ft 3008 Sq. Ft. @ 100%
Additional Floors
Enter total area in sq. ft for all other floors 3008
Total Area Entire Building 4512
STEP 2
F = Coefficient related to the class of construction as determined by using the
construction type found in SBCCI
Construction Type Class F Value
Frame 1 1.5
Joist Masonry 2 1
Non-combustible 3 0.8
Heavy Timber 4 0.8
Modified fire resistance 5 0.6
Fire resistive 6 0.6
Construction Class 1
Square Root of the Area x F x 18 1750 = C Value
Commerical
FIRE & RESCUE
ISO Fire Flow Worksheet
Needed Fire Flow Work Sheet (ISO formulas)
S 3rd Ave
Sundance Springs Comm Lot 2
Page 2/3
STEP 3 Multiply result of rounded off GPM by the Occupancy Factor (Oi)Occupancy Factor
Noncombustible (C-1) = No active fuel loads such as storage of asbestos,0.75
clay, glass, marble, stone, or metal products.
Limited - Combustible (C-2) = Limited fuel loads such as airports,0.85
apartments, art studios, auto repair, auto showroom, aviaries, banks,
barber shops, beauty shops, churches, clubs, cold storage warehouses,
day care center, educational occupancies, gas stations, green houses,
health clubs, hospitals, jails, libraries, medical labs, motels, museums,
nursing homes, offices, radio stations, recreation centers, and rooming
houses.
Combustible (C-3) = Moderate fuel loads such as auto part stores, auto 1.0
repair training center, bakery, bookstores, bowling centers, casinos,
commercial laundries, contractor equipment storage, dry cleaners with no
flammable fluids, leather processing, municipal storage buildings, nursery
sales stores, pavilions, pet shops, photographic supplies, printers,
restaurants, shoe repair, supermarkets, theaters, vacant buildings, and most wholesale & retail sales ocuppancies.
Free-Burning (C-4) = Active fuel loads such as aircraft hangers, cabinet 1.15making, combustible metals, dry cleaners using flammable fluids, feed
stores, furniture stores, kennels, lumber, packaging and crating, paper
products manufacturing, petroleum bulk distribution centers, tire
manufacturers, tire recapping or retreading, wax products, and woodworking shops.
Rapid-Burning (C-5) = Contents that burn with great intensity, 1.25
spontaneously ignite, have flammable or explosive vapors, or large quantities of dust such as ammunition, feed mills,
fireworks, flammable compressed gases, flammable liquids, flour mills,
highly flammable solids, matches, mattress factories, nitrocellulose-based
products, rag storage, upholstery shops, & waste paper storage.
Occupancy Class Selected (1 thru 5)3
GPM x Oi 1750
Page 3/3 FIRE & RESCUE
FIRE & RESCUE
ISO Fire Flow Worksheet
Needed Fire Flow Work Sheet (ISO formulas)
STEP 4 Now consider the exposure factor (Xi) - (Separation between buildings)
Distance (feet to the exposed building) Xi >3 stories
0-10 0.22 0.47
11-30 0.18 0.43
31-60 0.13 0.38
61-100 0.09 0.34
Distance, in feet, to the exposed building 20
Xi (from table)0.18
Multiply GPM from step 4 by (1+Xi)
Total From Step 4 2065
STEP 5 Approved Fire Sprinkler System? (Y or N)y
Take fire flow from step 5 and multiply by sprinkler credit of 0.25
Sprinkler credit 516
Now subtract sprinkler credit from fire flow in step 4
NEEDED FIRE FLOW 1500 GPM
Needed Fire Flow Work Sheet (ISO formulas)
ISO Fire Flow Worksheet
Hazen-Williams Calculations for Sundance Springs Comm Lot 2 Water Distribution System, from
Engineeringtoolbox.com online calculator
Water Main, 8” DIP
Service Line, 1” K-Copper, domestic flow
Service Line, 1.5” K-Copper, landscaping flow
Service Line, 4” Ductile Iron Pipe, fire flow, 1500 GPM
Service Line, 4” Ductile Iron Pipe, fire flow, 1080 GPM
Facility Name
Building address or number
Residential or Non-Residential
Minimum Pressure (psi) ** this is typically 35 psi
Fixture Value Number of Subtotal
Fixture or Appliance (at 60 psi)Fixtures Fixture Value
Toilet (tank) 4 6
Toilet (flush valve) 35 0
Urinal (wall or stall) 16 0
Urinal (flush valve) 35 0
Bidet 2 0
Shower (single head) 2.5 0
Sink (lavatory) 1.5 4
Kitchen Sink 2.2 1
Utility Sink 4 1
Dishwasher 2 1
Bathtub 8 0
Clothes Washer 6 0
Hose connections (with 50 ft of hose)
1/2 in. 5 2
5/8 in. 9 11 0
3/4 in. 12 0
Miscellaneous
Bedpan washers 10 0
Drinking fountains 2 2
Dental units 2 0 0
Combined Fixture Value 17
Demand (gpm) 17
Pressure Adjustment Factor 0.58
Total Adjusted demand (gpm)9.9
Water Demand Estimate Using Fixture Values
(Based on AWWA M22 Manual, Second Edition)
Sundance Springs Comm Lot 2