Stair Case Pressurization Calculation - Class A

Calculation for Stair case pressurization System . ST-1 & 2 CLASS A SYSTEM

Case-1 ; Considering only leakage through the Door at the ST-1 area

Double Door area ( only at Ground floor)

Height-H/(m) = 2.2 m

Width-D/(m) = 2.2 m

Total No of Door = 1 Nos

Total Area = 4.84 m2

Leakage factor for Double Door is , K 0.03

Air Flow rate Q , as per BS 5588

Q=0.83xAxP^0.5

Q=0.83x(1X0.03)x50^0.5

Q1 0.18 m3/s

Single Door Area (all the floor apart from Ground Floor )

Height-H/(m) = 2.2 m

Width-D/(m) = 1.1 m

Total No of Door = 29 Nos

Total Area = 70.18 m2

Leakage factor for single Door is , K 0.01 Air Flow rate Q , as per BS 5588

Q=0.83xAxP^0.5

Q=0.83x(29X0.01)x50^0.5

Q2 1.70 m3/s

Total Air Flow rate for ST-01

Q3 = Q1+Q2 Q3 = 0.18+1.7 m3/s 1.88 m3/s 3,980.66 cfm Increase by 50% 2.82 m3/s Q3 = 5,970.99 cfm Case-2 ; Considering one single door is opened (Class A system)

Single Door Area

Height-H/(m) = 2.2 m

Width-D/(m) = 1.1 m

2.42 sqm From the BS5588 ,velocity is to be 0.75m/s

V = 0.75 m/s Q4= AV Q4= 2.42X0.75 m3/s Q4= 1.815 m3/s 3,846.97 cfm

Total of case 1 & Case 2

Q= Q3+Q4 Q= 2.82+1.815 m3/s Q= 4.63 m3/s 9,818 cfm Total area A =

Total Volume Flow Rate 9,817.96 cfm

Add Duct leakages @ 15% 0.69 m3/s

1,472.69

cfm

Total Volume Flow Rate of the Fan should be 5.33 m3/s

11,290.65 cfm

According to the BS 5588 Staircase pressurization fan is to be single speed 1hr fire rating @300C

a) To calculate pressure required in stairwell to exhaust 1.815 m3/s to atmosphere via fire floor Area of single leaf door=2.2X1.1=2.42 sq.m

Area of exhaust vent = 1.815/2.5 =0.726 sq.m A.E = (1/A1^2+1/A2^2)^-0.5 = (1/2.42^2+1/0.726^2)^-0.5 = 0.70 sq.m P1=(Q/(0.83XA.E))^2 = (1.815/(0.83X0.7))^2 = 9.758902835 Pa

This is more than covered by 50 Pa

b) To calculate area of pressure relief Quantity of air to be wasted = 5.33 - 2.82

= 2.51 m3/s

Area of pressure relief = Q/(0.83XP^0.5) = 2.51 / (0.83X50^0.5)

= 0.428 sq.m

Let Height of Pressure relief damper = 0.7 m then Width will be = 0.428 / 0.7 = 0.62 m, say 0.65m

Static Pressure Calculations

Note:-1) The Equivalent Diameter Formula is: De = 1.3(ab)^0.625 / (a+b)^0.25

2) The friction loss and the velocity can be obtained from the charts knowing the flow and the eq. diameter

3) The equivalent length for an elbow can be obtained from the formula: Le = W exp [-2.13(H/W)^0.126 ln(0.33R/W)]

ST-01 & 02 - Presurization unit (11310cfm)@237Pa

Straight Ducts 1600 500 11,310.00 10 0.939 1550 500 10,933.00 4 0.926 1500 500 10,556.00 4 0.913 1450 500 10,179.00 4 0.900 1400 500 9,802.00 4 0.886 1350 500 9,425.00 4 0.872 1300 500 9,048.00 4 0.857 1250 500 8,671.00 4 0.843 1200 500 8,294.00 4 0.827 1150 500 7,917.00 4 0.812 1100 500 7,540.00 4 0.795 1050 500 7,163.00 4 0.779 1000 500 6,786.00 4 0.762 950 500 6,409.00 4 0.744 900 500 6,032.00 4 0.726 850 500 5,655.00 4 0.706 800 500 5,278.00 4 0.687 750 500 4,901.00 4 0.666 700 500 4,524.00 4 0.644 650 500 4,147.00 4 0.622 600 500 3,770.00 4 0.598 550 500 3,393.00 4 0.573 500 500 3,016.00 4 0.547 450 500 2,639.00 4 0.518 400 500 2,262.00 4 0.488 350 500 1,885.00 4 0.455 300 500 1,508.00 4 0.420 250 500 1,131.00 4 0.381 500 200 754.00 10 0.337 350 200 377.00 8 0.286 54 Fittings Elbow 1600x500 2 3 4.0 Reducer 29 1.0 19.1

Size Qty Eq. length (m) Friction Loss (Pa)

Width/(mm) Height/(mm) Volume flow Rate/(cfm) Length(m) Eq. Diameter(De) m

SAT(sound attonuator) 0 70

VAV 0 0

Flexible duct 0 0.3inch/100ft 0.00

sub total 89.14

Fire Damper Size Pressure Drop (Pa)

0

VCD Size Qty

Various 2

grilles Qty

Various 1

Preassure Drop (Pa) 197.20 Pa

Additional 20% 39.44 Pa

237 pa

Avg Pressure Drop/(Pa) 20

Avg Pressure Drop/(Pa) 10

Total pressure Drop accros the exhaust air side of FAHU-1 unite

3) The equivalent length for an elbow can be obtained from the formula: Le = W exp [-2.13(H/W)^0.126 ln(0.33R/W)] pa/m inch/100ft 0.57 0.07 5.740 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 2.296 0.57 0.07 5.740 0.57 0.07 4.592 TOTAL 78.064 Total Friction Loss(Pa) Friction loss

Calculation for Stair case pressurization System . ST-3 to 7 CLASS A SYSTEM

Case-1 ; Considering only leakage through the single Door at the ST-3 area

Double Door area ( only at Ground floor)

Height-H/(m) = 2.2 m

Width-D/(m) = 2.2 m

Total No of Door = 1 Nos

Total Area = 4.84 m2

Leakage factor for Double Door is , K 0.03

Air Flow rate Q , as per BS 5588

Q=0.83xAxP^0.5

Q1 =0.83X(1X0.03)X50^0.5

Q1 0.18 m3/s

Single Door Area (all the floor apart from Ground Floor )

Height-H/(m) = 2.2 m

Width-D/(m) = 1.1 m

Total No of Door = 6 Nos

Total Area = 14.52 m2

Leakage factor for single Door is , K 0.01

Air Flow rate Q , as per BS 5588

Q=0.83xAxP^0.5

Q2=0.83X(4X0.01)X50^0.5

Q2= 0.35 m3/s

Total Air Flow rate for ST-01

Q 3 = Q1+Q2 Q 3 = 0.18+0.35 m3/s 0.53 m3/s 1,119.56 cfm Increase by 50% 0.79 m3/s 1,679.34 cfm

Case-2 ; Considering one single door is opened (Class A system)

Single Door Area

Height-H/(m) = 2.2 m

Width-D/(m) = 1.1 m

2.42 sqm From the BS5588 ,velocity is to be 0.75m/s

V = 0.75 m/s

Q4= AV

Q4= 2.42X0.75 m3/s

Q4= 1.815 m3/s

3846.97 cfm

Total of case 1 & Case 2

Q= Q3+Q4

Q= 0.62+1.815 m3/s Q= 2.607 m3/s Q= 5,526 cfm Total Volume Flow Rate of the Fan should be 5,526.31 cfm

Add duct losses @ 15% 0.39 m3/s

828.95

cfm

Total Volume Flow Rate of the Fan should be 3.00 m3/s 6,355.26

cfm

According to the BS 5588 Staircase pressurization fan is to be single speed 1hr fire rating @300C

a) To calculate pressure required in stairwell to exhaust 1.815 m3/s to atmosphere via fire floor Area of single leaf door=2.2X1.1=2.42 sq.m

Area of exhaust vent = 1.815/2.5 =0.726 sq.m A.E = (1/A1^2+1/A2^2)^-0.5 = (1/2.42^2+1/0.726^2)^-0.5 = 0.70 sq.m P1=(Q/(0.83XA.E))^2 = (1.815/(0.83X0.7))^2 = 9.758902835 Pa

This is more than covered by 50 Pa

b) To calculate area of pressure relief Quantity of air to be wasted = 2.80 - 0.62

= 2.18 m3/s

Area of pressure relief = Q/(0.83XP^0.5) = 2.18 / (0.83X50^0.5)

= 0.371 sq.m

Let Height of Pressure relief damper = 0.5 m

then Width will be = 0.371 / 0.5 = 0.742 m, say 0.75m

Static Pressure Calculations

Note:-1) The Equivalent Diameter Formula is: De = 1.3(ab)^0.625 / (a+b)^0.25

2) The friction loss and the velocity can be obtained from the charts knowing the flow and the eq. diameter

3) The equivalent length for an elbow can be obtained from the formula: Le = W exp [-2.13(H/W)^0.126 ln(0.33R/W)]

ST-3 TO 7 - Presurization unit (6356cfm)@148Pa

Straight Ducts pa/m inch/100ft 750 650 6,356.00 10 0.763 0.57 0.07 5.740 650 650 5,448.00 4 0.711 0.57 0.07 2.296 650 550 4,540.00 4 0.653 0.57 0.07 2.296 550 550 3,632.00 4 0.601 0.57 0.07 2.296 450 550 2,724.00 4 0.543 0.57 0.07 2.296 350 550 1,816.00 4 0.477 0.57 0.07 2.296 350 350 908.00 4 0.383 0.57 0.07 2.296 34 TOTAL 19.516 Fittings Elbow 2100x1100 2 3 4.0 Reducer 6 1.0 4.0 SAT(sound attonuator) 0 70 VAV 0 0

Flexible duct 0 0.3inch/100ft 0.00

sub total 73.96

Fire Damper Size Pressure Drop (Pa)

0 0

VCD Size Qty

Various 2

grilles Qty

Various 1

Preassure Drop (Pa) 123.48 Pa

Additional 20% 24.70 Pa

148 pa

Total Friction Loss(Pa)

Size Qty Eq. length (m) Friction Loss (Pa) Width/(mm) Height/(mm)

Volume flow Rate/(cfm)

Length(m)

Avg Pressure Drop/(Pa) 20

Avg Pressure Drop/(Pa) 10

Total pressure Drop accros the exhaust air side of FAN-ST-1 unite

Friction loss Eq.

Diameter(De) m