Air transfer grilles for fire doors. Download. A rater-measured pressure differential of ≥ -5 Pascals and ≤ +5 Pascals (0. 6 inches : If the free area of grille is %, and side (a) is" , side (b) should be: 3. +27 (0)33 398 1100. ls in m = Throw distance to a bmaximum time averaged air vel ocity of 0. Construction Details All Dimensions ±1/16" Standard Finish: 01 White Finish 24 Mill Finish Optional Finish 02 Satin Silver 03 Black 28 Custom Color Extruded Aluminum Constructionjinteriordesignonline. Those results will be discussed in a future report. Genuine Comfort find that air return grilles tend to be the better choice between transfer grilles and air return grilles. Please watch our corporate video. 5mm. Aluminum Construction. Product 150 Intumescent Ventilation Grilles (SVG & HMG)blades. Series FB. 008. From standard grilles and registers, to its architectural line of Formations® linear slot diffusers, along with a newly released series of displacement diffusers, METALAIRE has the air devices to meet every need. 004 0. The high-low offset is located in an interior wall framing cavity adjacent to the door between the room and common space. Normally, with a single RA grille that'll be where the filter is. My 1st choice would be jumper ducts for aesthetics and better air volume capabilities. Model DG-FC Louvre Grilles are available in stock sizes and can. Carnes also offers a line of Door/Transfer Grilles to allow airflow from one area to the next while maintaining privacy with Light Tight construction. 2. Sight-Proof Door Grille. Can provide up to 60 minutes fire +. Duct 6. A high performance, standard vision intumescent air transfer grille for doors, walls and ducts. Specifications - Gilberts (Blackpool) EN English Deutsch Français Español Português Italiano Român Nederlands Latina Dansk Svenska Norsk Magyar Bahasa Indonesia. Presto ! Instant return ducts. Note: When framing both sides of the door or partition opening, use the TGF frame with the TG Grille. 42671 posts · Joined 2008. 6" Inch Door Air Vent Grille Two Sided Ventilation Cover - White - Overflow Ventilation Grill - Door Vent Cover - Free AIR Flow Between Rooms -. Download. Transfer Grilles offer the largest free area possible with the option of a sight-proof or light-proof core. * Note: 30mm protrusion with minimum depth of door DSR/425/285/9010-Matt Type Nominal width Nominal height Finish ORDER EXAMPLE Nominal W x H + 51 Nominal W x H - 25 60 Nominal W x H 40. ) Ak Factor Core Velocity Velocity Pressure Neg. The 2 most practical options are soundproof blankets and soundproof curtains. DSR units will only provide acoustic isolation improvements over that of a clear aperture. 004 0. These are specially designed which also giving a pleasing appearance to suit architectural needs. Operation: The units are operated by a 24V DC electrical supply. Our Acoustic Transfer Grilles are available in a range of sizes and finishes to suit your requirements. The damper units are slimline with an overall thickness of only 35mm, allowing these kits to be flush fitted within the conventional 35mm & 45mm nominal fire door leaves. Extensive product range. TAMARACK R. Intumescent air transfer grilles serve the same purpose but also expand when exposed to heat from a fire, sealing the gap in a fire door or wall – meaning the fire rating of the compartment is maintained. Displacement diffusers. Air transfer grilles. Fascia Cover Grilles For Fascia Grille options please refer to Gilberts Air Distribution Catalogue “Grilles” section Damper & Mounting Frame Damper with vertical blades for air passage and 15mm returned edge all round for ixing to structure. 4 out of 5. In this case, their height will be determined by your system. 002 0. Blade Grille. . Such spaces include storage rooms and restrooms. Please watch our corporate video. ) while at the same time offering effective protection against flames, smoke and gases in case of fire. Soundproofing transfer grilles is relatively easy, although the solutions aren’t permanent. A range. Gilberts are a local, trustworthy company based in Gosport who have been offering a wide range of services. 18 Registers, grilles and diffusers. Optional equipment and. Our range of combined intumescent fire + smoke air transfer grilles can be used in all applications where cold smoke containment is required. Intumescent Air Transfer Grille. uk. Discover our wide range of products within the Door grilles category and benefit from 20+ years of expertise Personal advice Competitive prices. w. Established in 1972 in the family garage, HVC Supplies has developed steadily over more than 45 years to become the industry leading company it is today. 0 My Basket. In a fire, our intumescent air transfer grilles expand to form a solid block that stops fire spreading. Aluminum Transfer Grille (ATG) Overview. The easiest way to reduce noise traveling through them is to cover them with an absorptive or sound-blocking material. 25. These fire resistant air transfer grilles are developed to allow the free circulation of air at room temperature through construction elements (walls, doors etc. Opening for the transfer of ambient air between two adjacent areas is referred to as a “Air Transfer Opening. NV4: Slimline surface mounted with a non-chevron blade, designed to suit fire doors. These grilles are compatible with doors or partitions as thin as 1 3/8 in. Construction is from all aluminium extrusion with fixed full chevron blades. duct or transfer grille), and perimeter walls insulated in accordance with Section N1102. It adjusts to suit a door thickness from 1-3/8" to 1-7/8". Duct registers, grilles and diffusers shall be installed in accordance with the manufacturer’s instructions. Allowing air movement through a door or wall without compromising fire integrity. CT-700L. Series GA WFV, WFVG, WFG Fire-rated Air Transfer Grilles. View Product. : Bedrooms with a design supply airflow ≥ 150 CFM are specified with any combination of transfer grilles, jump ducts, dedicated return ducts, and/or undercut doors to achieve a Rater-measured pressure differential ≥ - 5 Pa and ≤ +5 Pa with respect to the main body of the dwelling unit when all air handlers are operating. Available in either steel or aluminum construction with either single or double flange frame options. Designed for door transfer in dark room/light proof applications. Visit the Quietcool Store. Return Air Pathways – RAP. GRILLES AND REGISTERS F DOOR/TRANSFER GRILLES PERFORMANCE DATA: DOOR/TRANSFER GRILLES – 5100 AND 6100 SERIES MODELS: 51DG, 61DG Listed Duct Size (inches) Alternate Sizes (inches) Core Area (sq. ) Nominal Size Core Velocity (fpm) 100 150 200 250 300 350 400 Velocity Pressure (in. Air Ventilation Grilles, Fixed Blade & Adjustable Louvres, Ventilation Diffusers, Air Supply & Air Exhaust Valves, HVAC Grilles, Air Security Grilles, VAV & CAV Units, Radiant Panels and Trench Heating supplies from the industries leading manufacturer. £7. Slim-profile, versatile intumescent block grilles for use in ceilings, doors, walls or ducting. Designed for door mounting. DESCRIPTION: Construction: Frame and blades are 6063 extruded aluminum alloy with 200-R1 satin anodized finish. fitting a conventional grille to a wall or door will totally negate other measures taken to prevent the spread of fire, hot smoke andGrilles Type AH · WAP · AF Installation situation Type AH, AF ≥X Nomenclature ‡ in l/s/m based on 1000mm nominal grille length . The grilles are carefully constructed to be unobtrusive in appearance for architectural excellence. Transfer grilles, door undercuts and wall grilles are all acceptable means to allow air to flow around the house. O. Fisher & Paykel 48" Grill with Infrared Sear Burner, Natural Gas - BE1-48RCI-N. door transfer grille. Rack and pinion. Established in 1972 in the family garage, HVC Supplies has developed steadily over more than 45 years to become the industry leading company it is today. With high quality and competitive pricing these grilles form the back bone of a standard offering that will meet any application requirements. Gilberts Non-Vision Louvred Grille | Air Transfer Grille Cover. 005 150. Steel Maximum Security Grille with Square Perforations. PERFORMANCE DATA STG Core Area (sq. Even more important is the operation of these systems, particularly mechanical and plumbing. Catalog Pages . Jackshaft (indicates damper positioning) 9. Air Handling Units, Ceiling Cassettes, Wall Mounted. A door or partition non-vision grille incorporating inverted chevron blade…. Air Distribution Solutions - Gilberts Grilles : About Gilberts: Grille Product Info : Diffuser Product Info: Louvre Product Info: Damper Product Info: Domestic Product Info :. Sight-Proof (ATG1) + Finely spaced, chevron style blades provide an attractive sight-proof appearance. Technical support: [email protected]. The face velocity through return grilles with 'V'core should not exceed 2m/s. Telephone: (01253) 766911 Fax: (01253) 767941 e-mail: sales@gilbertsblackpool. The Gilberts non-vision stainless steel louvred grille is suitable for surface mounting in both door and wall applications and is ideal for both standard air transfer and fire rated applications where intumescent type fire dampers are utilised. These airflow volumes are then used to size and lay out the ducts. Door/Transfer Grilles. com 0344 856 0594. SCHAKO sight-proof transfer grilles are overflow grilles for walls and doors and are used between two adjacent rooms for pressure compensation. Blades are chevron in configreation and are mounted in a fixed position ina rigid PVC track in an integral part of the frame. A variety of frame types and mounting options are available to suit any application. £7. Duct diffusers. 3 (7) Download. Also, there is NO indication of the how to determine the required size of the permanent openings of any type. Acoustic Transfer Grilles DSR Acoustic transfer grille DSRX Acoustic transfer grille for variable depth DSR2 Back to back acoustic transfer grille. NV1 is the Vision proof core only. ArchiExpo offers ventilation grates and transfer grilles in aluminum, steel, stainless steel and other materials. Static Pressure 100. fitting a conventional grille to a wall or door will totally negate other measures taken to prevent the spread of fire, hot smoke andGrilles Type AH · WAP · AF Installation situation Type AH, AF ≥X Nomenclature ‡ in l/s/m based on 1000mm nominal grille length . My question is, can you essentially install a duct from the location of the grille, to somewhere else inside the house? (for instance down a hallway, it will still have a vent for air return, just moving that away from my actual. SG-PS. V-shaped Deflection Vanes Set on 1/2” Centers. Aluminum door grilles. View Products. Your guide to trusted BBB Ratings, customer reviews and BBB Accredited businesses. e use of a room as a return plenum is a code violation. Nominal sizes 150 × 105 – 1500 × 985 mm. 01924 444 174 [email protected] could be soil gases such as radon or fumes from paints, pesticides, or fuel stored in the crawlspace. Door grilles are required for the transfer of air from one room to another Material Door grille manufactured from. James Gilbert & Son specialises in high quality decorative metalwork. The 9700 provides a single side mounting frame for use where appearance is an issue on only one side, as in a utility or storage closet. The aluminium ‘V’ shape chevron blade mounted on a close Grilles View Products Diffusers View Products Domestic View Products Supply & Extract Valves View Products Finish Options View Data Sheet Download. With minimum and maximum security options as well as a variety of mounting types, these grilles are suitable for supply and return applications. Original plan was to take my central air return in the hallway and stub ducts in the attic to get individual air returns to each bedroom. Our intumescent grilles and fire dampers combine air movement with fire protection. View Product. 1"x3. Model includes a v-shaped louver providing a sightproof return or exhaust grille regardless of the viewing angle. Drop one in one side then go on the other wall behind and drop the other in. Optional equipment and. Gilberts NV Series provides a comprehensive and traditional range of vision proof grilles to suit all manner and type of air transfer application through doors, walls and partitions. They can be used for providing dampers in ductwork. 010Security Grilles Direct have fitted window protection for commercial sectors such as retail organisations, IT companies and schools, providing effective deterrents against potential intruders. DG-3 - Double Flange Door/Transfer Grille. One grille is located high on the wall on. O & MInstructions. Supplied in 2. Blades are chevron in configreation and are mounted in a fixed position ina rigid PVC track in an integral part of the frame. HVAC OV 17. Damper body formed in langed Z sections 52 x 35 x 196. X. The DV series are large format grilles for door ventilator applications. The aluminium ‘V’ shape chevron blade mounted on a close 8mm pitch renders see through vision impossible and when double banked in a matt Grille Options & Accessories. The LVH intumescent air transfer grilles available from Lorient Pty Ltd are specifically designed for use in fire rated door assemblies where pressure relief or extra ventilation is required. It adjusts to suit a door thickness from 1-3/8" to 1-7/8". Acoustic, smoke + fire containment systems. ; Transfer grilles shall use 50 square inches (of grille area) to 100 cfm (of. 0 ( 0) From £45. ) Ak Factor Core Velocity Pressure Neg. This will reduce moisture problems and help eliminate mold and mildew build up. - Economic Stock Availablity. We are committed to clarity in pricing which is unambiguous although this Site does not contain any pricing information. Blades are chevron in configreation and are mounted in a fixed position ina rigid PVC track in an integral part of the frame. Used to allow for air movement between two conditioned spaces while preventing vision. Displacement diffusers. Working from a purpose designed production and warehousing facility in the West Midlands, we are capable of producing everything from the. 3. For Enquiries contact us on +44 (0)1384 376555; Recently viewed items ;The Halton TVC transfer grille can also be used together with an opposite frame accessory (OF) to complete transfer unit for 25 to 50 mm thick doors or partition walls. 021 250. Heavy Duty Registers and Grilles. 450x92. ×. Fire resistant doors, fire resistant walls, fire resistant partitions. Non-vision door transfer grilles are two piece grilles designed to be installed in doors or partitions. The next steps are to perform testing to validate the CFD model for room-to-room air transfer via over-door and bottom-of-door transfer grilles, with the eventual goal of using that model to determine the expected airflow volume through the transfer grilles under various conditions. DG-3 - Double Flange Door/Transfer Grille. g. Login / Register; 0117 9372846;. DL. and is greater in size than transfer. 5 to 92 mm. ) 0. From the family garage to 70,000 square feet today. Door / Transfer Grilles Products Matching Your Selection METALAIRE is the flagship brand of Metal Industries Inc. See the crime statistics in your area here. Lorient Intumescent Air Transfer Grilles are used to provide an answer to situations where ventilation is required in fire compartment walls or doors. Maximum size is 36" x 36" (914 x 914). Minimum size is 6" x 4" (152 x 102). comDoor Grille TROX (South Africa) (Pty) Ltd. Submit a request online and get a quote from your local representative within 4 hours. Especially useful for narrow doors or fireblock installations. The DV series are large format grilles for door ventilator applications. The LVH44 dampers can be assembled in multi-modules to protect large. An electromechanically operated shutter smoke mechanism closes its slats in the event of a fire alarm going off, thus stopping cold smoke and flames from passing. Nailor 51DG and 61DG Series Door Grilles are designed to be completely sight proof and unobtrusive in appearance. Inverted V type grille bar for best vision proof quality and airflow. Both the Halton TVC grille and opposite frame are screwed to the wall or door. transfer grills over doors to bedroom/office. TRH (Transfer grilles) 1. The Waterloo fire rated ventilators are suitable for 1 hour rated doors and partitions. press machinery and production techniques the FB700 is<br />. Attenuators, Acoustic Louvres/Enclosures, Acoustic Transfer Grilles, Acoustic Fire Doors, Anti-Vibration Springs and Hangers. Gilberts NV Series provides a comprehensive and traditional range of vision proof grilles to suit all manner and type of air transfer application through doors, walls and partitions. Volume dampers or other means of supply air adjustment shall be provided in the branch ducts or at each individual duct register, grille or diffuser. It is designed for air transfer applications through fire rated doors and walls. Description. Download the pdf to learn. Share. It should not beSupply grille of horizontal-vertical double deflection with air flow regulation incorporated_RTHV . , offering a complete line of air distribution and air terminal products. 4 Dimensional Data Hole - 4mm dia. Extract air diffusers. The air transfer grilles are connected, via a control panel, to a standard fire alarm system. Table 1 shows the sizing specifications for using 10”, 12” or 14" wide transfer grilles with 70% free area as a function of room supply air flow. Available in nominal 2" (51) increments. Door / Transfer Grilles Products Matching Your Selection METALAIRE is the flagship brand of Metal Industries Inc. We are always on hand to help advise on suitability. Gilles Gilbert was born on March 31, 1949. Gilberts NV Series provides a comprehensive and traditional range of vision proof grilles to suit all manner and type of air transfer application through doors, walls and partitions. PERFORMANCE DATA STG Core Area (sq. 60% Free Area. The DGC is manufactured as per the DG but in a channel frame. NV1 Grille. Favorite. 5. These grilles also have a 6mm vermin proof mesh fitted to both faces, so unwelcome. Where return air is taken from a closet smaller than 30 square feet (2. We can supply vents in a bespoke design to suit your requirements. For the size of the installation hole, see Dimensions (L-10)x (H-10). CERTIFICATIONS. Our grilles have high quality paint finishes and accessories to suit your individual requirements. The above-door transfer grille simply has two grilles located above the door between the room and common space, one on each wall, with offset baffles to limit sound transmission. 065 400. Company. The Perfect Balance In-Door Return Air Pathway is a grille installed into the bottom. Grille face made of aluminium with powder coat finish. Air Distribution | GDL Air Systems Limited | EnglandDomestic Warm Air Grilles. 1 Double Defl ection Grille AUR 6 1. Over the last 135 years we've produced architectural quality metal works for some of the biggest brands on the planet, yet we don't forget our. 2. This 24V DC supply providesToday the range includes duct mounting smoke/fire dampers, curtain fire dampers, smoke evacuation dampers, intumescent air transfer grilles and air volume control dampers Engineering led our products are designed. For the size of the installation hole, see Dimensions (L-10)x (H-10). With a dedicated design team working on both new developments and. Clean-room diffusers. ft. Overall Face Height = Specified Door Opening + 1 34 3 3 9 16 XG-DGDFSS - Surface Mount Face View Neck Size MinMax Width448 Depth448 Greenheck Fan CorporationP. Download quality free BIM & Revit Components for the G Series - Transfer Grilles from Colman Air Distribution for free. Published by Raúl Galdrán from BIMETRICAL on 1/8/2018. Published by Raúl Galdrán from BIMETRICAL on 1/8/2018. fAdjustable Blade Grilles. Can be used to provide resistance to fire and hot smoke of up to 60 minutes in doors and walls. In many cases, pipes and ducts. when doors are closed. Behind the scenes, numerous FB700 door transfer grilles and NV (non vision) were installed to maintain fire compartments, with FBL60 (one hour intumescent) fire blocks for optimum safety. A fire-rated version is also available. 1 KB Views: 234. ago. A high performance, standard vision intumescent air transfer grille for walls, doors and ventilation ducts. SERIES FB700 Air Transfer Grille Gilberts. In the event of an alarm condition, or power failure, the smoke shutters shut, preventing the passage of cold smoke. Heavy Duty Registers and Grilles. Reinforced terminals. 5mm. 02576. Day-to-day this enables efficient ventilation but during a fire will seal shut, stopping the fire spreading further. It may be surprising that just these three systems — mechanical, electrical and plumbing (MEP) — can make up as much as 15% of the total environmental footprint of a building's. NR Ratings and Core Areas Air Volume m3/s Face. Or leave the doors open, cut the bottom off the door, 3" will help but looks weird. Gilberts (Blackpool) limited is one of the largest UK manufacturers of Grilles, Diffusers, Louvres, Smoke/Fire Dampers and Natural Ventilation Systems for the Heating, Ventilating and Air Conditioning industry. Skip to content The IFD-D intumescent door grille kit is suitable for new or existing Proprietary fire resistant doorsets that may require air transfer or pressure relief. Type NV6 Vision proof flanged grille suitable for surface mounting onto doors, wall or partitions. The negative pressure on that duct of your HVAC system will mess with the air distribution in weird (bad) ways, and it's almost certainly not big enough for what the dryer will be trying to pull. Showing 11 of 122 products. If one grille is to be used per door then the volumetric flow needed will be: 1152/2 = 576 cubic metres per hour. Use your stud finder and level to map out the exact location where you’re going to cut through the wallboard. The Perfect Balance is a transfer grill designed to fit in the door. Certifire approved. On the roof, 3 number penthouses, ranging from 1m x 1. Heavy duty registers and grilles work well in any application where the air volume is large and easy removal for cleaning is required. Install the Pyroplex Fire. Gilberts Blackpool. Our combined intumescent fire & smoke air transfer grilles can be used in applications where cold smoke containment is required. Fisher & Paykel 48" Grill with Infrared Sear Burner, LP Gas - BE1-48RCI-L. Operation: The units are operated by a 24V DC electrical supply. For both fire and smoke protection, see the Lorient LVN20S Air Transfer Grille. Supply registers usually have the damper handle so you can adjust it. Nominal sizes 225 × 125 – 1225 × 525 mm. Shop everything from registers, vent covers, diffusers & more at the Home Depot. 7" x 3. 020 inch water column) is acceptable for rooms with a design airflow ≥150 cfm. Door grilles provide visual security and limits light while allowing air transfer through doors or walls. Adjustable from 1-3/8" to 2 1/4" door thickness. Transfer Grille Baffle. Grilles; Registers; Diffusers; Air Distribution; Fire Dampers; Access Doors; Air and Sound Controls; Louvers and Dampers. Supplied in two pieces it lends itself to easy installation in a standard 54mm thick fire door, + when finished with a colour co-ordinated edge flange, results in an attractive but efficient air transfer feature. Air transfer grille FGS - type MMS represent passive fire protection, designed with the help of compartmentalization to prevent the spread of toxic gases, smoke and fire. Designed for door transfer in dark room/light proof applications. Transfer grilles are designed for use in doors and partitions to allow for smooth transfer of air between spaces. Browse a range of intumescent vents also known as air transfer grilles and fire vents. 170 in stock for next day delivery. Envirograf Firoblok | Intumescent Sleeve for Services - Silver, 360 X 204 X 60mm. Grilles are available in a range of sizes and offer up to 60 minutes integrity in accordance with BS 476-22. Aluminum door return grille with sight-proof blades parallel to short dimension. application in offices, shops, schools, hospitals and many<br />. But wherever air moves, fire and smoke can travel too. AG20 Bar Grille. The DGA4 vents in the toilets feature a louvred face for a horizontal air pattern. Gilberts Blackpool. or use our online contact form. WFV, WFVG, WFG Fire-rated Air Transfer Grilles. NV4 is a Set of two lightproof core grilles with 32mm flange borders. GREENHECK heavy duty grilles are an excellent choice for return or exhaust in high traffic areas such as gymnasiums. Please note the existing silver finish will now be supplied in a new industry-standard satin silver finish of RAL 9006. Amazon. Transfer grilles are designed for use in doors and partitions to allow for smooth transfer of air between spaces. 51EC - Aluminum • Eggcrate • Core Only. 1. Skip to contentThe IFD-D intumescent door grille kit is suitable for new or existing Proprietary fire resistant doorsets that may require air transfer or pressure relief. 1 (7 reviews) Extruded aluminum grille supply. GILBERTS DAMPERS 8 MAY 2005 PUBLICATION Features 60 or 120 Minute Fire Rating. One grille is located high on the wall on. when doors are open. Trimec. In the event of an alarm condition, or power failure, the smoke shutters shut, preventing the passage of cold smoke. The high-low offset is located in an interior wall framing cavity adjacent to the door between the room and common space. Gilberts NV Series provides a comprehensive and traditional range of vision proof grilles to suit all manner and type of air transfer application through doors, walls. (Matt black finish). Ventilation grille with angled blades. A transfer grille is a grille or register installed in the wall or above the door to connect the closed room with an open space such as a hallway or living room, thereby providing an. <br><br>The Perfect Balance In-Door Return Air Pathway is designed to maintain adequate air flow between rooms and eliminate pressure imbalancesallowing each room. Over the years we have built a reputation for providing an extensive range of attractively styled, contemporary, value engineered products at the best in. Lorient Code of Conduct. 012. 005 150. Type NV6 Vision proof langed grille suitable for surface mounting onto doors, wall or. The DG door transfer grilles are designed for use in doors where constant air transfer with non-vision is required. We take great pride in offering an exceptionally high level of customer service and in building long-term relationships with our clients, whether they be consultants. Grilles, Diffusers, External Louvres, Smoke Dampers, Fire Dampers, Volume Control Dampers. The damper units are slimline with an overall thickness of only 35mm, allowing these kits to be flush fitted within the conventional 35mm & 45mm nominal fire door leaves. Standard finish is natural anodised while other finishes including powder coat are available to suit the interior and architectural design requirements. Horizontal and vertical moving slats for an individual regulation as they adapt the air range and the air stream to the needs of the zone. TRH (Transfer grilles) 1. Original plan was to take my central air return in the hallway and stub ducts in the attic to get individual air returns to each bedroom. . transfer of room air to another, i. Our range of Non-Vision Grilles models include: NV1: Standard flanged grille. 7" x 3. Please note - A very. ) Nominal Size Core Velocity (fpm) 100 150 200 250 300 350 400 Velocity Pressure (in. That grille is either just an open transfer that let's the air leave the room via pressure differential so it can get back to the air handler or it's a ducted grille (not usually) that goes back to the air handler. other commercial projects. Minimum size is 6" x 4" (152 x 102). If the grille is installed close to the fan, a damper may need to be closed to direct air farther from the fan. The Perfect Balance is typically installed in a bathroom or mechanical room door for the purpose of providing make up air for the exhaust fan. Volume flow rate range 4 – 535 l/s or 14 – 1926 m³/h. ft. Transfer Grilles offer the largest free area possible with the option of a sight-proof or light-proof core. 5 inches (38 mm) or the closet shall include a louvered door or transfer grille with a minimum net free area of 30 square inches (194 cm 2). uk.