MODEL OAL. Water Penetration. Water Penetration. Free Area OAL PERFORMANCE REGISTERS GRILLES &

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1 MODEL OAL The OAL series of etruded aluminum stationary louvers is manufactured for installation in eterior wall openings. They are designed to allow fresh air and ehaust air to flow into/out of the building while maintaining a clean architectural appearance. The OAL series is available in 2 (OAL-2) and 4 (OAL-4) depths. 45 blade angle Flanged frame or channel frame Insect/bird screens available OAL PERFORMANCE Performance Variables The resistance of a louver to water penetration is an important design consideration. A louver s water resistance performance is usually determined by a specific set of laboratory tests in which water is directed over the louver face without eternal wind, referencing only the velocity of the air entering the louver. This industry standard aids the design engineer in sizing intake louvers for NORMAL WEATHER conditions, but is not a guarantee that, for all variable conditions of wind and rain, a tested louver will prevent water penetration. Metal Industries Inc. certainly does not offer such a claim. Designers of critical installations should consider their local weather records, and provide a reasonable safety factor by sizing louvers at some point less than the manufacturer s maimum recommended free area velocities. Maimum Recommended Velocities for Minimum (Intake Louvers Only. No Maimum for Ehaust Louvers OAL-2 F OAL-2 C 575 fpm GRILLES & INDUSTRIAL GRILLES OAL OAL-4 F OAL-4 C 525 fpm Curves 1 and 2 show the relationship between water penetration and free area velocity in Feet Per Minute (fpm). AMCA (Air Moving and Conditioning Association) Standard 500 is the basis for the louver free area calculations ONLY as shown in Figures 1 and 2 on page 4. Louver static pressure drop data shown in Curves 3 and Curve #1 for OAL Curve #2 for OAL Metal Industries, Inc. GR 1

2 GRILLES & 2000 Curve #3 for OAL INDUSTRIAL GRILLES Velocity In FPM Through (Standard Air.075 LBS./Cubic FT.) OAL Static Pressure Drop Inches W.G. OAL PERFORMANCE Performance Variables Louver free area, static pressure drop and water penetration should all be considered in the proper selection of Outside Air Louvers. Louvers should not be specified to meet a percent free area requirement since the percent free area varies with the louver size and model. Louvers should be specified to meet a maimum allowable pressure drop for a specific volume of design CFM with acceptable water penetration levels. The eamples on this page show how these factors are interrelated. OAL-2 or OAL-2 Louver Sizes Eample: Select a Model OAL-2 F and OAL-2 C for fresh air intake application to handle 5000 CFM at less than inches W.G. for minimum water penetration. Step 1: Refer to Louver Performance Curve No. 3 and determine the free area velocity at 0.94 inches W.G. A pressure drop of inches W.G. limits the free area velocity to approimately 575 fpm. Step 2: Use the formula for finding in sq. ft. Step 3: Refer to Curve No. 1 at a Free Area Velocity of 575fpm, water penetration is slight, approimately ounces of water per square foot of free area in 5 minutes at 2< per hour rainfall rate. penetration for Models OAL-2 and OAL-2 C starts to become of concern above 615 fpm free area velocity. Step 4: Use the following formula to calculate the total water penetration of the louver required for the application: = Louver Free Area in sq. ft. = 8.7 sq. ft..75 = Step 5: Refer to models OAL-2C, OAL-2F, Table 2 and select a Louver with approimately 8.7 sq. ft. of free area. Several selections are available. Ounces of water per sq. ft. of.6525 ozs. in 5 minutes (sq. ft.) = CFM Velocity (fpm) (sq. ft.) = 5000 CFM 575 (fpm) = 8.7 sq. ft. GR 2 Metal Industries, Inc. For complete product specifications and submittal data, visit us at

3 Width Height (Sq. Ft.) in 5 Minutes ounces H ounces H ounces H ounces H 20 Eample: Select a Model OAL-4 and OAL-4 for fresh air intake application to handle 5000 CFM at less than 0.04 inches W.G. for minimum water penetration. Step 1: Refer to Louver Performance Curve No. 4 and determine the free area velocity at 0.04 inches W.G. A pressure drop of 0.04 inches W.G. limits the free area velocity to approimately 525 fpm. Step 2: Use the formula for finding in sq. ft. (sq. ft.) = (sq. ft.) = CFM Velocity (fpm) 5000 CFM 525 (fpm) = 9.5 sq. ft. Step 4: Use the following formula to calculate the total water penetration of the louver required for the application: = Louver Free Area in sq. ft. Step 5: Refer to models OAL-4C, OAL-4F, Table 1 with approimately 9.5 sq. ft. of free area. Several selections are available. Width Height Ounces of water per sq. ft. of = 9.5 sq. ft..03 =.285 ozs. in 5 minutes (Sq. Ft.) in 5 Minutes ounces H ounces H ounces H ounces H 20 GRILLES & INDUSTRIAL GRILLES OAL Step 3: Refer to Curve No. 2. At a Free Area Velocity of 525 fpm, water penetration is slight, approimately ounces of water per square foot of free area in 5 minutes at 2< per hour rainfall rate. penetration for Models OAL-4 and OAL-4 C starts to become of concern above 550 fpm free area velocity. Selections at higher free area velocities are possible for installations with built-in positive protection of equipment against water penetration. In these situations, the recommended free area velocities for minimum water penetration may be eceeded Curve #4 for OAL-4 Velocity In FPM Through (Standard Air.075 LBS./Cubic FT.) Static Pressure Drop Inches W.G Metal Industries, Inc. GR 3

4 GRILLES & INDUSTRIAL GRILLES OAL Figure 1 Braces and Mullions - OAL-2 C & OAL 4 C Face Reinforcing Brace when specified Figure 2 Braces and Mullions - OAL-2 F & OAL-4 F Face Reinforcing Brace when specified Rear Reinforcing Brace on Widths Greater than 48 Rear Reinforcing Brace on Widths Greater than 48 Typical Mullions For Louvers Greater Than 60 Figure 3 Face Flange with Epansion Anchor No. 6 SMS Zinc Plated Typical Mullions For Louvers Greater Than 60 No. 6 SMS Zinc Plated Type OAL PERFORMANCE Louver Installation Details Louvers can be installed in wall openings by a variety of methods. Louvers are available with flanges for overlapping wall openings and with channel periphery for recess in wall openings. Face flange Models OAL-4 F and OAL-2 F are provided with front flanges on head, sill and jambs. Model OAL-4 F has 3/4< wall opening overlap and Model OAL-2 F has a 1/2 inch wall opening overlap. Attachment is suggested through the face flange with lead epansion shields and stainless steel bolts or screws to suit the conditions of construction. (Plase see Fig. 3). Angle Anchors Continuous angles or 6< long sections of 1 1/4< 1 1/4< aluminum angles for 4< and 2< deep face flanged louvers and 1< 5/8< 1/4< aluminum angles for 4< and 2< deep channel louvers can be used at jambs, sills, and heads for attachment from the rear. Bolt the angle leg to the wall opening. It is suggested that a coating of mastic sealant be used between the wall and angle leg surfaces. Fasten the remaining angle leg to the louver. On continuous angles, installation bolts should be spaced on 18< centers. (Please see Fig. 5). Figure 4 Epansion Anchor Through Jamb Figure 5 Continuous Angle Anchor Angle Lead Epansion Anchors Stainless steel bolts with lead epansion shields can be used through holes drilled in louver jambs. Large flat washers of the same material as the bolts should be used with mastic sealant between the washers and louver jambs. (Please see Fig. 4). Vertical Mullions Flat batten vertical mullions are available for multiple louver sections and are field installed with stainless steel screws by others. The flat batten mullions are 0.081< thick aluminum strips available undrilled in 5 ft. and 10 ft. lengths in 1 1/4< widths for Models OAL-2 C and OAL-4 C and 1 1/2< widths for Models OAL-2 F and OAL-4 F louvers. (Please see Fig. 1 & 2). Installation, caulking around perimeter of louvers and wall openings, hardware and structural materials are furnished by others. Any of the recommended methods, as well as other means of attachment and installation as detailed by the architect can be employed. GR 4 Metal Industries, Inc. For complete product specifications and submittal data, visit us at

5 SERIES OAL PERFORMANCE DATA MODEL OAL-4C, OAL-4F, TABLE 1 Model Height GRILLES & INDUSTRIAL GRILLES OAL 2015 Metal Industries, Inc. GR 5

6 GRILLES & INDUSTRIAL GRILLES OAL SERIES OAL PERFORMANCE DATA MODEL OAL-2C, OAL-2F, TABLE 2 Model Height GR 6 Metal Industries, Inc. For complete product specifications and submittal data, visit us at