ECG Engineering Consultants Group

PROJECT NAME: Nozha City Centre. DATE: MAY-2007

PROJECT NO.: 1127 COMPUTED BY: A.Salah

Area Served: Car Park

Ventilation Type: Mechanical Ventilation Fans

Brief description: Exhaust through high temperature rated fans.

Fresh Air make-up through Ramps and slab openings.

Design Parameters:

Fire Size = 3 x 3

Fire Area = 9 m2

Heat Rate ( Qr) = 278 kw/m2

Heat Production (Q) = 2502 kw

Perimeter ( P ) = 12 m

Smoke Layer Height (Y) = 2.5 m

Smoke Layer Depth (Db) = 1.5 m

Air Specific Heat ( Cp) = 1.01 kj/kg.k

Outside Air Temp. (To) = 30 deg.c (303 k)

Calculations

Min. Smoke Flow Rate (Mf) = 0.188 x P x Y1.5

= 0.188 x 12 x 3.95

= = 8.918 kg/s

Temperature Rise (Tr) = Q / (Mf x Cp)

= = 277.8 Deg.c

Max. Smoke Temp. (Tc) = To + Tr

= = 307.8 deg.c ( 581 k )

Air Volume Flow rate (Ma) = Mf x Tc / (1.2 x To)

= 8.918 x 581 / (1.2 x 303)

= 14.24 m3/s =

= 30,182 CFM Note:

As per ANSI/ASHRAE standards 62.1.2004

Recommendation provide 3.7 lit/sec/m2

For 12000 m2

As per NFPA part 92B

Direct drive two speed smoke exhaust fans of 14.1 m3/s (30,000 cfm) rating shall be provided in each parking zone ,

Fire rated for 300oC for 1 HR. Motor and Bearing shall be out of air stream.

SMOKE MANAGEMENT DESIGN CALCULATION SHEET

Car parking area divided into 5 fire zones 2500 m2 each , Total exhaust 150,000 cfm.

Make up fresh air shall be supplied from Ramps and Slab opening.

cfm = 12000 x 3.7 x 2.1 = 93.240 cfm.

Shall be divided into 5 exhaust fans two speed fire protected each one is 20 000 cfm for ventilation.