20120312 Sewer STEP Tank Sizing 01142013 SEWER STEP TANK SIZING
PROJECT, Yelm McDonald's Addition
PR0.7ECT NO.: i 1815.OI
DATE. � I/1�J2013,., �: -,
The sizing calculations below have been based on the following information:
• The Washington State DOE Criteria of Sewe� Works Design
• City of Yelm Development Guidelines
• Water Use Records from City of Yelm
McDonald's located at 505 Yelm Avenue West currently uses 207 Cubic Feet a day.
(based on attached water records)
• Ex. Daily Water Use: 207 Cubic Feet
• Increase Water Use by 32% (827 s.f. Addtion) 273 Cubic Feet
• Daily Water Use: 2042 Gallons
Using the above information the calculations from the DOE manual can be solved.
• Detention Volume from Pg C1-32
V = (2.0) Q
Q=Peak Daily Flow 2042 Gallons
Non Resid. Strength = 2.0 2
V=Liquid Volume 4084 Gallons
• Working Volume from Pg C1-32
• Working Volume is defined as the difference between the peak inflow and
pumps ability to keep up with the flow.
• O.S. 20 GPM duplex pump system will be installed in the new second tank. It has
the ability to convey 1,200 GPH. The pump will be capable of conveying the whole
daily flow in less than 4 hours. This pumps flow is substantially higher than the
actual. All duplex systems are required to have OSI 20 pumps
•The standard City of Yelm float settings should be used (5.0")
• Emergency Power Outage Storage Volume from Pg C1-32
• 24 hours of additional storage volume is required.
• 2042 gallons have been included.
• City of Yelm requires a transfer switch and generator connection to be
installed. Refer to Sewer Addendum notes for type and model info.
���: 'i���D
FEB 0 8 2013
' �3�Y:
Tank Sizing Summary
Based on standard concrete 3,000 gallon step tank 84" in depth
Standard tank contains 35.71 gallons per 1" of storage.
STEP Tank Detention:
• Required Detention Volume 4084 Gallons
• Ex first 3000 gallon tank outflow pipe at 65" from bottom 2321 Gallons
• New second 3000 gallon tank pumped at 50" from bottom 1786 Gallons
• Total Detention Provided 4107 Gallons
• Additional Detention Volume Provided 23 Gallons
STEP Tank Detention:
• Required Working Volume (5") 179 Gallons
Elev 50" to 55"
Emergency Tank Storage (Elevation 55" to 84"):
• Required Emergency Volume 2042 Gallons
• Emergency Volume Provided in Ex First Tank 678 Gallons
(84" - 65") * 35.71
• Emergency Volume Provided in Ex First Tank Risers
n(1')�*4' * 7.48 gal/ft' 94 Gallons
rr(1.25')2*4' * 7.48 gal/ft3 147 Gallons
• Emergency Volume Provided in Second Tank 1036 Gallons
(84" - 55") * 35.71
• Emergency Volume Provided in Ex First Tank Risers
rr(1')z*4' * 7.48 gal/ft3 94 Gallons
rr(1.25')2*4' * 7.48 gal/ft3 147 Gallons
• Emergency Volume Provided 2196 Gallons
Total Tank Volume
• Detention Provided 4107 Gallons
• Working Volume 179 Gallons
• Emergency Volume 2196 Gallons
6481 Gallons
2
14/19�2012 12:21 FAX 3604384348 CITVOfVELM f�002/002
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Account Number-01-0261-02 N80 ENTERPRISES INC Service Address; 505 YELM AVE W
Se�v�ce: 100 005 COMMER�IA�IN 1 Meter:21Q593Q6A
, ' � Read' , ' Total ' ' Demand , Readfng
Monih Date I'reviaus• Curr,ent � ConsumptlQn � Read Consumplion Flag SourCe Occuparrt
Ye�r;2012 Tot�l 9
Sep 09/30/2�12 124370 124950 5800 RegulAr Hand Held q2
' Aug 08/31(2012 123700 �24370 6700 Regular Hand Held 02
Jul 07/31J2q12 123030 123700 6700 Regular Hand Held 02
Jun 06/30/2�12 122480 123030 5700 Regular Hand Meld o2
Msy 05/31/2012 121895 122460 5654 Reguiar Hand Held �2
Apr 04/30/2012 12125Q 421695 8454 Regu�ar Hand Held 02
Mar 03l31l2012 120680 12125� 5600 Regular Hand He1d b2
Feb 02/2912012 1200A5 72069b 6450 Reguler Hand Hald pZ
Jan U1/3112072 118470 12�045 5750 Regular Hand Heid 02
Year:2011 Totel 3
�ec 12/31/2411 118910 1i9470 5800 Regular Hand Held 02
Nov 11l30/2011 118190 118910 7200 Regular Hend Heid 02
�ct 10I91/2011 797515 118190 6750 Regular Hsnd Held Q2
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