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Ducted system is connected to Fan Coil Units, Air Handling Units & Fresh Air handling units for distribution of air. Units are selected depending on Air volume and ESP (External Static Pressure). Let us discuss few cases of duct arrangement and application.
Duct Sizing: Fan Coil Units
Air Flow: up to 2000 CFM
Eternal Static Pressure: < 60 Pa.
FCU - Bed Room / Hotel Room - Refer Fig : 1
Where there shall be minimal Space for duct work. In such case we need to follow the grille size as duct size.
Figure : 1 Figure : 2
FCU - Bed Room / Living Room - Refer Fig : 2
Where we have enough length to install mouth piece, straight length, elbow and taper piece for supply air grille.
Straight Duct
Velocity Up to 800FPM
Friction Drop < 0.08 in. WC/100Ft
Taper for Grille
Same Size as Supply Air Grille.
FCU - Office Rooms - Refer Fig : 3
Where we have enough length to distribute the duct across the room.
Main Duct
Velocity Up to 1000FPM
Friction Drop < 0.08 in. WC/100Ft
Branch Duct
Velocity Up to 700FPM
Friction Drop < 0.08 in. WC/100Ft
Dropper (Diffuser) / Shoe Collar (Grille)
Same as Diffuser, Griller size.
Duct Sizing: Air Handling Units
Air Flow: > 2000 CFM
Open Offices
Main Duct
Velocity Up to 1200FPM
Friction Drop < 0.08 in. WC/100Ft
Branch Duct
Velocity Up to 800FPM
Friction Drop < 0.08 in. WC/100Ft
Sub Branch Duct
Velocity Up to 600FPM
Friction Drop < 0.08 in. WC/100Ft
Dropper (Diffuser) / Shoe Collar (Griller)
Same as Diffuser, Griller size.
| Duct Sizing: Fresh Air Handling Units Building / Towers Riser Duct Velocity Up to 1500FPM Friction Drop < 0.1 in. WC/100Ft Floor Entry Duct Velocity Up to 1200FPM Friction Drop < 0.08 in. WC/100Ft Branch Duct Velocity Up to 800FPM Friction Drop < 0.08 in. WC/100Ft Sub Branch Duct Velocity Up to 600FPM Friction Drop < 0.08 in. WC/100Ft Fresh Air Discharge Velocity Up to 400FPM Friction Drop < 0.08 in. WC/100Ft Bell Mouth with wire mesh. |
|---|
Duct Material
Space | Application | Duct Material |
|---|---|---|
Hotel, Shopping Mall, Commercial, Residential - Rooms, Flats, Offices, Shops, Corridors | Supply Air, Return Air, Fresh Air, Toilet Extract | G.I, P.I |
Ware House, Super Markets, Show rooms | Supply Air | G.I, P.I & Fabric Duct |
Hotel, Office, Residential - Riser / Shafts | Fresh Air, Toilet Extract, Kitchen Extract | G.I |
Residential - Kitchen | Kitchen Extract | G.I |
Restaurant & Commercial Kitchen | Kitchen Extract | Fire Rated Duct |
Fire & Safety Services | Staircase & Lift Well Pressurization, Corridor Smoke Extract & Make up, Car park Extract & Make up. | Fire Rated Duct |
At BTU Electromechanical Works LLC, Dubai, UAE, we execute HVAC Design & Build projects ranging 250 TR to 660 TR such as 5 Star Hotels, Logistics Centers, Community Malls. Also we provide technical support such as Heat Load, Duct Sizing, Pipe Sizing, ESP Calculation, Pump Head Calculation and Complete HVAC System Design, to equipment suppliers, MEP Contractors and Clients. We can be reached at projects@btullc.com, www.btullc.com.