Return Air Grille Sizing Chart

340 cfm of return air x 87 5 298 cfm.

Return air grille sizing chart. We are after the ability to move 980cfm so you now divide this number by 400 fpm yielding 2 45 or 2 5. Ventilation systems for ventilation and air handling air change rates ducts and pressure drops charts and diagrams and more. Proper sizing and orientation of grilles registers and diffusers may seem like such a simple thing but it s an area where confusion and mistakes are commonly made.

Wxh wxh wxh wxh wxh wxh wxh wxh 80 6x6 7x5 9x4 90 7x6 8x5 10x4 100 7 8x6 9x5 11x4 125 7x7 9x6 11x5 13x4 150 8x7 9x6 12x5 15x4 175 8 8x8 9x7 10x6 13x5 17x4. A return air grill should be sized for an air speed of 300 500 fpm feet per minute. The louvers positioned on a fixed bar return grille are further apart and are designed much more aerodynamically than those of a stamped face grille.

Convert this measurement to inches. Return a return draws air into a return duct system with negative pressure compared to the space usually via a fixed grille but. Particle diameter strainer and filter mesh size vs.

4 ton unit x 144 square inches 576 squared. Aluminum return grille 45 degree deflection 1 2 blade spacing blades parallel to long dimension. Step 1 open up the cabinet of your furnace to gain access to the service plate.

400 fpm is the median air speed for this calculation. Look on the plate to see how many btu or british thermal units your furnace puts out. Do this by multiplying 2 5 x 144 360 square inches.

Return filter grille specification chart. Proper sizing of the return air filter grille is required for the furnace to function correctly. The square root of 576 is 24.

Table 4 2 return air duct installation sizes based on 05 inches of pressure drop per 100 ft round duct rectangular duct cfm dia. D minus 2 3 4 d heavy guage steel construction concealed hinges equipped with filter retainers uses 1 nominal disposable filters finish. Calculate the square root of the total.

1 5 8 c minus 2 3 4. It s a 1600 cfm system with 200 cfm of outside air 200 1600 12 5 of outside air. An acoustical return sound boot designed for ceiling plenum return air applications.

Aluminum aeroblade return grille for narrow tee ceilings 1 2 blade spacing with 45 degree deflection blades parallel to short dimension. Air intakes and outlets ventilation systems air intakes and outlets rules of thumbs. Take 100 12 5 to find a multiplier of 87 5.

Velocity classification of ventilation ducts recommended. First let s define some terms. A high flow return grille or fixed bar type return grille has essentially more open area to let air flow through the actual grille.