SUMP PIT AND SUMP PUMP SIZING
DESIGN CALCULATION SHEET
Project no.: Date: Sheet No.: 1 of 3 Computed by: SYED SAAD ALI
Subject: Sump Pump Calculation Checked by:
Building: Parking Approved by:
Determining Sump Pump Flow Rate
Assumptions:
1- Rainwater coming from ramps is totally removed by trenches
2- Sprinkler discharge is the only source of water
Fire Data:
Parking Type of Hazard Ordinary group I
Sprinkler protection Area (ft2) 130
ENGR. SYED SAAD ALI
Area of sprinkler Operation (ft2) 1500
Density (gpm/ft ) 2
0.15
Flow from Sprinklers (gpm) 225
Flow rate Analysis
* For a 90 min operation of the fire pump the total flow from sprinklers is 20250 Gal = 76545 liters
*Adopting a flow of 225 gpm or 14.19 l/s for a sump pump means that:
1. All sprinklers are activated within 1500 ft2
2. The sump pump will remove all the water dishcarged instantaneously in 90 min
* If the total amount of 20250 gal are to be removed in 3 hours the pump flow rate would be 7.1 l/s
* If the total amount of 20250 gal are to be removed in 4 hours the pump flow rate would be 5.3 l/s
* The number of sprinkler in the operating area will be 11.54 say 12
Depending on the layout this number could be up to 14
* For a total flow rate of 225 gpm, the individual sprinkler flow rate is 18.75 gpm
* Assuming 3 sprinklers are first activated the total discharge flow is 56.25 gpm or 3.55 l/s
* Trench Data : Trench Average Height (m) 0.15
Length of trench serving one pit (m) 45
Volume of water in trenches (m ) 3
6.75
Pump flow rate to remove water in trenches in 15 min 7.5 l/s
Pump flow rate to remove water in trenches in 30 min 3.75 l/s
* Based on the above, three significant flow rate figures are simulated in the Table below
Pump flow rate (l/s) 14 14 14 7 7 7 4 4 4
Total water removal
duration (min) 30 60 90 30 60 90 30 60 90
* Parking area served
by one pit (m2) 2300 2300 2300 2300 2300 2300 2300 2300 2300
Max volume of water in
parking (liters) 76545 76545 76545 76545 76545 76545 76545 76545 76545
Volume removed by
sump pump (liters) 25200 50400 75600 12600 25200 37800 7200 14400 21600
Volume of wter in
trenches (liters) 6750 6750 6750 6750 6750 6750 6750 6750 6750
Remainig Volume of
water on floor (Liters) 44595 19395 -5805 57195 44595 31995 62595 55395 48195
Height of water on
floor of parking (cm) 1.94 0.84 -0.25 2.49 1.94 1.39 2.72 2.41 2.10
www.linkedin.com/in/engrsyedsaadali
SUMP PIT AND SUMP PUMP SIZING
Design calculation sheet
Project no.: Sheet No.: 2 of 3 Computed by:
Subject: Sump Pump Calculation Checked by:
Building: Parking Approved by:
Pump Flow Rate
Design flow rate of the sump pump 4 l/s
Selecting Duplex operation of the the sump pumps, the flow rate of each one to be selected is 2l/s
Thus when water reach a high level in the pit, the second pump operate and the total flow rate would be 4 l/s
Minimum Required Sump Volume:
T min Q
V req=
4
ENGR. SYED SAAD ALI
Where: Vreq is the required sump volume between the start level and stop level of the pump
Tmin is the minimum pump cycle time
Q is the pump flow rate
Tmin 600 seconds
Tmin 10 min The total # of starts & stops / hour is 6
Q 2 l/sec
Vreq 300 Liters OR 0.3 m3
The Total Volume for the sump with 2 pumps
Vtot = Vreq + (n-1) ΔH х S
Vtot Total sump volume between the start level and stop level of the pump
n total number of pumps
ΔH The constatnt height between the start up of two pumps (in meters)
S Surface area of the sump (in sq meters)
n 2
ΔH 0.2 m
S 1 m2
Vtot 0.5 m3
The Total Volume for the sump with 2 pumps with cyclic alternation
Vtot = Vreq/n + (n-1) ΔH х S
n 2
ΔH 0.2 m
S 1 m2
Vtot 0.35 m3
The pit is designed to have a sump volume of 0.5 m3
www.linkedin.com/in/engrsyedsaadali
SUMP PIT AND SUMP PUMP SIZING
Design calculation sheet
Project no.: Date: Sheet No.: 3 of 3 Computed by:
Subject: Sump Pump Calculation Checked by:
Building: Parking Approved by:
Pump Head Calculation
Static 5.0 m 5.0 m
Force Main Pipe Run 130 m 3.0 m (7 ft/1000 ft friction loss for a 4 '' pipe)
Force Main Pipe Run 50 m 2.3 m (14 ft/1000 ft friction loss for a 3 '' pipe)
Residual 1.0 m
Total Head 9.0 m
ENGR. SYED SAAD ALI
Safety 9.9 m
Pump head 10 m
Pump Flow 2 l/s
Notes:
1- In pumping stations do not use 2 1/2" on the discharge of waste, use 3" pipe
www.linkedin.com/in/engrsyedsaadali
6"
3'-0"
3'-0"
ENGR. SYED SAAD ALI
4'
2'
4'
www.linkedin.com/in/engrsyedsaadali
