hci engineering - thornton · findings hci engineering does not foresee adverse impacts to...

HCI ENGINEERING A division of HABERER CARPENTRY INC. May 1st, 2014 Attn: Heath Klein, P.E.

City of Thornton, Development Engineering 9500 Civic Center Drive Thornton, CO 80229

Re: Utility Letter for T-Mobile Site at Plazas Las Americas Dear Mr. Klein, This letter serves to inform you that the proposed development for the T-Mobile Store Site at 88th Avenue and Washington Street complies with the City of Thornton and North Washington Street Water and Sanitation District (NWSWSD) standards and specifications for water and sewer services. The following letter is written on behalf of Washington Box LLC, Denver CO 80209.

Area Map

621 SOUTHPARK DR., SUITE 1600 – LITTLETON, CO 80120 - (720) 252-3484 EMAIL: [email protected]

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Description of Property: The proposed T-Mobile Store Site is located on Lot 5A4, City View Heights Subdivision, Filing No. 1, Amendment No. 3, in the northwest quarter of Section 26, Township 2 South, Range 68 West, of the Sixth Principal Meridian, City of Thornton, County of Adams, State of Colorado. This site will be part of the existing Plaza Las Americas commercial development consisting of a grocery store and other retail buildings and pad sites. The property currently consists of approximately 0.7 acres of previously graded, partially vegetated, undeveloped land. The site has approximately 10 feet of grade change from the high point nearest 88th Avenue to the low point at the southwest corner. The existing grade across the middle of the site is approximately 2.5%. The site slopes from north to south at about 2.5% (the exception is the landscape lining the west boundary—this landscaping forms a drop-off to Washington Street which is not considered as part of the overall slope. The proposed development will include vertical construction of approximately 2,520 square feet of building for the purpose of cell phone sales/service center and parking areas with associated drive lanes, parking stalls, trash/recycling enclosure, utilities and landscaping. Wet Utilities: Fire Flow Requirement: The fire flow requirement for this building, based on Type V-B construction, a fire area of approximately 2,520 square feet, and no automatic fire sprinkler protection, is 1,500 gallons per minute (gpm) at a minimum residual pressure of 20 pounds per square inch (psi). This flow shall be provided by a minimum of one (1) hydrant, with a maximum spacing of 500 feet between hydrants. The maximum distance form any point on the front (east) side of the building to the nearest fire hydrant shall be 250 feet. The quantity and locations for the existing fire hydrants near this building site appear to be sufficient to meet these requirements. A hydrant flow test conducted by North Washington Street Water and Sanitation District on November 19, 2012, utilizing existing fire hydrants in close proximity to this building site, indicated that the existing water supply near this building is sufficient to provide the required fire flow of 1,500 gpm and 20 psi. Water System: The overall Plaza Las Americas has an existing 8” water main looped though the development. An existing 8” main is located within a water easement on the south boundary of this site. The proposed site will include the installation of a new 1.0” tap and meter to service the proposed tenant space. Per conversations and flow information provided by North Washington Street Water and Sanitation District (NWSWSD) the static pressure in this main is 60 PSI, refer to figure C. The anticipated Water demands for the T-Mobile are summarized below.

• Domestic 16GPM, per fixture count formula, see figure A. • Landscape irrigation 14-18GPM, per landscape architect (off our irrigation).

Using the above flow values a service line calculation was completed for this site to confirm that the proposed 1.0” service will provide adequate flows for this development, refer to figure B for detail calculations. The proposed building will not require a fire suppression system.


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Sewer System: The overall Plaza Las Americas is serviced by and internal 8” Sewer Main. This main is located roughly 250 feet south east from the proposed building. The site will connect to this internal 8” main via a 4-inch sewer service line. This line has been designed to convey 16 GPM determined by the fixture count above. Using this flow a normal depth and flow velocity calculation was completed to demonstrate compliance with the city and utility district requirements, refer to figure D for detailed calculations. Summary: Based upon these findings we believe that the site will have adequate water and sewer service. Given these findings HCI Engineering does not foresee adverse impacts to downstream or adjacent properties due to the development of this site. Sincerely Cole C Haberer, P.E. #43259 HCI Engineering Attachments: FIGURE – A, Vicinity Map FIGURE – B, Water Service Calculations (2 sheets) FIGURE – C, Flow Test Info FIGURE – D, Sewer Service Calculations


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ColeH

CCH STAMP

ColeH

CCH SIG BLUE HEAVY

HCI ENGINEERING A division of HABERER CARPENTRY INC.

Fixture Demand Form Figure - B1

621 Southpark Dr., Suite 1600 - Littleton, CO 80120 - (720)-252-3484 Email: [email protected]

1

FIXTUREFIXTURE VALUE

60 PSINO. OF

FIXTURESFIXTURE VALUES

Bathtub 8 0Bedpan Washers 10 0Bidet 2 0Dental Unit 2 0Drinking Fountain - Public 2 1 2Kitchen Sink 2.2 1 2.2Lavatory 1.5 2 3Showerhead (Shower Only) 2.5 1Service Sink 4 1 4Toilet - Flush Valve 35 0Toilet - Tank Type 4 2 8Urinal - Pedestal Flush Valve 35 0Urinal - Wall Flush Valve 16 0Wash Sink (Each Set of Faucets) 4 0Dishwasher 2 0Washing Machine 6 0Hose (50 ft Wash Down)

- 1/2 in. 5 0 - 5/8 in. 9 0 - 3/4 in. 12 0

(per figure 4-5 of AWWA M22 Manual) 20.2

Adjusted gpm 16.16

Pressure Adjustment Factor TableWorking Pressure at Meter

Discharge (psi)35405060708090

100

Working Pressure at Meter Discharge (psi) 40

Pressure Adjustment Factor

(per table 4-1 of AWWA M22 Manual)

11.212.1

0.740.80.91

1.091.171.251.34

6.77.28.19

9.810.5

COMBINED FIXTURE TOTAL VALUE

Average Flow from 50 ft of 5/8-in. Hose and Sprinkler (gpm)


Service Line Sizing Figure - B2


2

Step 1 - Head loss in pipe

L (Length) 27 ftD (diameter) 0.995 inches (Use internal pipe diameter for service lines, RE: table 5-1)

Q (flow rate) 16.16 gpm (Provided from fixture count)

C (Hazen-Williams C-factor) 130 unit-less (Hazen - Williams C-facors between 150-130, 130 conservative)

hp (Piping Head Loss) = hp = 10.4(L)*((Q/C)1.85)*(D-4.87) = 6.08 ft

Step 2 - Minor loss in meter

k (minor loss) 4.6 unit-less (per table 5-3 of AWWA M22 Manual)

hm (Meter head Loss) = hm = [k(Q2)]/(383*D4) = 3.20 ft

Step 3 - Minor loss in bends / fittings

k (minor loss - bend r/D = 1) 0 unit-less (per table 5-2 of AWWA M22 Manual)

hm (Bend head Loss) = hm = [k(Q2)]/(383*D4) = 0.00 ft

k (minor loss - 90deg elbow) 0.3 unit-less (per table 5-2 of AWWA M22 Manual)


k (minor loss - Contraction) 0 unit-less (per table 5-2 of AWWA M22 Manual)


k (minor loss - Ball Check) 4.5 unit-less (per table 5-2 of AWWA M22 Manual)

hm (Corp stop) = hm = [k(Q2)]/(383*D4) = 3.13 ft

Step 4 - Total head loss

htot (Total head loss) = Pipe loss + Meter loss + Minor losses = 12.62 ft

Step 5 - Allowable head loss

zm (Elevation @ Main) 5287 ftzc (Elevation @ Customer) 5296.32 ftpm (Pressure @ Main) 60 psipc (Pressure @ Customer) 40 psi

ha (Allowable head loss) = ha = (zm - zc) + 2.31(pm - pc) = 36.88 ft

Step 6 - Sizing Check

Service line check = ha ≥ htot, Service line OK if not RESIZE = OK


SEWER SERVICE CALCULATIONS Figure - D


1

UnitsRoughness Coefficient, n 0.013 N/AChannel Slope, S 0.02 ft/ftPipe Diameter, D 4 inPipe Radius, r 2 inDischarge, Q 16.16 gpm

0.036 cfs

UnitsQ_full 0.269 cfsQ_act 0.036 cfsQ/Q_full 0.134 N/A

(from chart) d/D 0.29 N/A0.097 ft

(from chart) v/v_full 0.72 N/Av_full 3.08 fpsv_actual 2.22 fps ≥ 2.0 fps OK

Formulas:

Parameters

Results

𝑑𝑑𝑛𝑛

𝐷𝐷 = 1.335𝑛𝑛𝑛𝑛𝑆𝑆

38�

𝑛𝑛= 0.463∗𝐷𝐷83� ∗ 𝑆𝑆

𝑛𝑛

𝑛𝑛 = 𝐴𝐴𝐴𝐴

hci engineering - thornton · findings hci engineering does not foresee adverse impacts to...

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