603. Commercial Grilles, Registers and Diffusers. Introduction 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. Showing 11 of 122 products. Door / Transfer Grilles Products Matching Your Selection METALAIRE is the flagship brand of Metal Industries Inc. Ross MacGugan of Ernest Griffiths, explains: “Gilberts’ grilles and diffusers were the most suitable technically and aesthetically for the project. V-shaped Deflection Vanes Set on 1/2” Centers. Habitable rooms only shall be required to meet these requirements forEngera Bathroom Door Air Vent Grille Two Sided Ventilation Cover for Restroom, Warehouse, Storage Doors | Interior Door Transfer Grill 453mm x 91mm (18. 5mm. For more friendly and professional advice on air grilles, please get in touch via our contact us page or give us a call on 01842 765657. Designed for installation into fire resisting doors, walls and ducts. Gilberts’ NV3 door transfer grilles allow Regulatory flow of fresh air whilst being vision proof. 1H 1V 2H 2V OBSS ED DT-2M. Used to allow for air movement between two conditioned spaces while preventing vision. Discreet, but attractive, this robust extruded aluminium grille incorporates a slotted, linear airway across its length and locates at the bottom of the doorsingle doors, double doors and louvre screens. 301. co. These fire resistant air transfer grilles are developed to allow the free circulation of air at room temperature through construction elements (walls, doors etc. 6 SERIES GP Security Grilles 150 200 250 300 400 500 600 PIVOT LINE GRILLE HEIGHT - mm ALTERNATIVE SIZE FROM PIVOT 150 POINT 200 250 300 400 500 600 GRILLE WIDTH - mm 100 50 40 30 20 10 5 4 3 2. Can be used to provide resistance to fire and hot smoke of up to 60 minutes in doors and walls. Wrapping up smoke and fire protection with our range of Fire Dampers, Smoke Dampers, Smoke/ Fire Dampers, Intumescent Air Transfer Grilles and Air Volume Control Dampers all developed to the latest test standards. Ventilation grille with angled blades. uk HomeDoor grilles are seldom used nowadays for two reasons 1. sales@gdl. 6") HVAC OV 17. View an intumescent ATG fire test here. Description. These are specially designed which also giving a pleasing appearance to suit architectural needs. Bright White or Satin Anodized finish. WFV, WFVG, WFG Fire-rated Air Transfer Grilles. g. Begin by selecting a space over a doorway and measure the metal frame. Transfer grilles, door undercuts and wall grilles are all acceptable means to allow air to flow around the house. 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. For more friendly and professional advice on air grilles, please get in touch via our contact us page or give us a call on 01842 765657. Cover grille (not included) Duct SERIES FB Door, Wall & Partition Mounting Intumescent Air Transfer Grilles Gilberts FB Series provides a compact, ef椀cient range of intumescent seals designed to satisfy many types of air transfer application in of椀ces, shops, schools, hospitals and many other commercial projects. Standard and bespoke aluminium louvres offering excellent functionality and rain defence. 4. Shop our great collection of registers & grilles at everyday low prices. Static Pressure 100. Duct Smoke/Fire DampersCombined smoke and fire damperssuitable for use in all types of HVAC ductwork. The damper can be suitably masked on both sides either with steel type A grilles or aluminium non-vision type B grilles. When posting in certain forums, knowing your location will. 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. Use your stud finder and level to map out the exact location where you’re going to cut through the wallboard. Can provide 180 minutes fire resistance. . BBB Accredited Door and Gate Operating Devices near Victoria, BC. 14 (58 grilles required) 0. Supplied in 2. 2. Discreet, but attractive, this robust extruded aluminium grille incorporates a slotted, linear airway across its length and locates at the bottom of the door. Maybe you can have transfer grilles installed to those rooms verse ducted returns. 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. 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. Normally, when there is ducted returns, the filter is located at the air handler. - Individually Adjustable Aerofoil Blades. Secure the system into place using steel pins [not supplied]. DG-3 - Double Flange Door/Transfer Grille. Available in either steel or aluminum construction with either single or double flange frame options. <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. If transfer grilles or jump ducts are used, refer to the balancing report provided by the HVAC contractor for the bedroom air flows to size the grilles or ducts. Series AV Door Transfer Grille. Day-to-day this enables efficient ventilation but during a fire will seal shut, stopping the fire spreading further. With high quality and competitive pricing these grilles form the back bone of a standard offering that will meet any application requirements. With this new Series Gilberts provide a comprehensive range of stainless steel grilles and diffusers designed to suit the most demanding of projects. These are particularly suitable for doors to staircases etc. Career. Pyrogrille air transfer grille allows free air flow and provides up to 60 minutes fire protection. 18 Registers, grilles and diffusers. 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. Clearance dimension 430x75 mm. Fabricated in a plain industrial grade 304 and 430 stainless steel the units are very robust and are suitable principally for Acoustic, smoke + fire containment systems. AG60 Bar Grille. Contact Us. Meanwhile, the house is directly connected to the outside through that transfer grille. application. Downloads. O & MInstructions. Transfer Grilles offer the largest free area possible with the option of a sight-proof or light-proof core. Alternatively, secure the system using self-tapping screws. View Product. Grilles are fitted into walls and some doors; and ductwork to keep fresh air circulating. Air Transfer Grille Introduction Gilberts FB700 Series presents a range of Mild Steel Louvred Grilles designed to satisfy all types of air transfer application in offices, shops, schools, hospitals and many other commercial projects. The standard finish will be RAL9010 or polyester powder coated to. Envirograf Firoblok | Intumescent Sleeve for Services - Silver, 360 X 204 X 60mm. Return Air Pathways – RAP. A fire-rated version is also available. The 61DG Series Door Grille may also be used as a transfer grille and in place of standard design exhaust and return air grilles where it is important that the interior of the plenum or duct be concealed. Published by Raúl Galdrán from BIMETRICAL on 1/8/2018. Intumescent air transfer grilles allow movement of air when fitted into doors, walls and ductwork in a building. 048 350. The LVN20S provides a unique solution to the problem of containing both fire + smoke in emergency conditions yet offering good air transfer through doors in everyday use. Our Acoustic Transfer Grilles are available in a range of sizes and finishes to suit your requirements. Typical Building Sector : Commercial,Dom. AGS-T. Floor diffusers. Steel Maximum Security Grille with Square Perforations. 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 materials. Model includes a v-shaped louver providing a sightproof return or exhaust grille regardless of the viewing angle. The high-low offset is located in an interior wall framing cavity adjacent to the door between the room and common space. 14" x 14" White Aluminum Transfer Door Grille w/out Frame (TG Series) ADD TO CART. Reinforced terminals. Construction is from all aluminium extrusion with fixed full chevron blades. Stainless Steel Door Grille with Single Flat Frame (Auxiliary Frame, Dual Core) The 9700 series transfer grilles are designed to ensure visual privacy while providing air circulation from one area to another. Minimum Unit Size is 6”x4” with a Maximum. Sight-Proof Door Grille. 3 (7) Download. Where return air is taken from a closet smaller than 30 square feet (2. AGS-T read more. 012. The LVH20S damper is a unique combination of intumescent slats to provide two hour fire resistance + excellent insulation properties together with a servo powered set of shutter plates that control cold + warm smoke. All manufactured from 1. Lancashire FY4 4QT. Series PE Perforated Face Extract Grilles. The transfer grille sizing includes allowance for one 32" by 1/2" door undercut. Soundproofing transfer grilles is relatively easy, although the solutions aren’t permanent. Door grilles provide visual security and limits light while allowing air transfer through doors or walls. Door Furniture; Drawers and Drawer Runners; Eyes; Feet; Fixings Fasteners; Formed Section; Gastronorm Containers; Gates; Glass Canopy; Handles. 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. HVAC OV 17. Allowing air movement through a door or wall without compromising fire integrity. fAdjustable Blade Grilles. December 19, 2020 ·. Even more important is the operation of these systems, particularly mechanical and plumbing. Allowing air movement through a door or wall without compromising fire integrity. Catalog. 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. Carpets will filter the air and remove all the candle soot and other airborne particulate, as it is forced under the bedroom door due to a high pressure difference. We are a manufacturer of Grilles, Diffusers and Louvres with a special emphasis in the fabrication and technical knowledge of Swirl Diffusers. From the family garage to 70,000 square feet today. SG-SD. These grilles are compatible with doors or partitions as thin as 1 3/8 in. NV6 is a Vision proof flanged grille suitable for surface mounting onto doors, wall or partitions. uk . Share. Air Velocity : 75 m/s. Login / Register; 0117 9372846;. Extract air diffusers. London’s Decorative Metalwork and Metal Grille Specialist. Optional equipment and. Countersunk holes. Series NV Vision Proof Transfer Grilles. Working from. Total No of Grilles = 10m3/s = 28. 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. In fact, everywhere I've worked it's mandated by code. All-in-one intumescent block grille with faceplates. (Matt black finish). Series GE Eggcrate Grilles. METALAIRE is the flagship brand of Metal Industries Inc. Please watch our corporate video. Allaway Acoustics. Transfer Grille. Make your expertise uniquely valuable. Air Flow : 21 m3/h. Catalogue DIFFUSER. From the GFX/600/2 & 3 sizing chart this indicates a unit with approx Max Vol of 175 l/s. 012. Aluminum door return grille with sight-proof blades parallel to short dimension. 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. Door Transfer Grilles. On the roof, 3 number penthouses, ranging from 1m x 1. £7. This 24V DC supply provides Today 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 to offer the highest level of performance safety and security and are tested to the relevant BS/EN standards as well as CE marked. NV3: Double layered grille intended for dark rooms (supplied as two modified NV1 grilles). 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 grille vanes are individually adjustable to allow jet spread or deflection to be set within 45 of the duct axis. ” In light of this, what exactly are transfer grilles? Typically, a transfer grille or register is inserted in the wall or above a door to link a closed room with an open area such as a corridor or living room, so giving a second. The Perfect Balance In-Door Return Air Pathway is a Durable ABS plastic grille with a noise and light dampening baffle that is installed into the bottom of interior doors. If transfer grilles or jump ducts are used, refer to the balancing report provided by the HVAC contractor for the bedroom air flows to size the grilles or ducts. The problem is that sound (and a small amount of light) pass freely through the vents negating all privacy of closing the door. Aluminum door grilles. That does not even come close to the negative pressure issues it throws the rest of the home into. 3. Our weather louvres, louvre screens, clip-on louvres, penthouse louvres and louvre doors are provided with high quality paint finishes and accessories to suit your individual requirements. With a dedicated design team working on both new. Because transfer grilles connect two rooms or a room and a hallway, there is nothing that is blocking sound between the two areas. Intumescent air transfer grilles allow movement of air when fitted into doors, walls and ductwork in a building. Flush mounted ,non vision door or partition grille. This reduces noise and increases airflow. Download catalogue. Take a flow hood and check cfm with the door open and the door closed, with a 1" undercut on a bedroom door you will have a serious cfm drop. Grille face made of aluminium with anodised finish. Grille face made of aluminium with anodised finish 30 mm wide front border Countersunk holes Optional equipment and accessories Grille face in RAL CLASSIC colours Installation subframe Matching rear frame for door installation. Description. Transfer grille examples to alleviate pressure differences. DSR units will only provide acoustic isolation improvements over that of a clear aperture. Shop everything from registers, vent covers, diffusers & more at the Home Depot. 001. ) 0. centrally located return air of which you can. Door/Transfer Grilles. 001 0. TAMARACK R. Showing 11 of 122 products. 008 0. View Products. Door / Transfer Grilles Products Matching Your Selection METALAIRE is the flagship brand of Metal Industries Inc. Jet velocity is approx 1. XG-DG Series. 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. 1 (7 reviews) Extruded aluminum grille supply. In many cases, pipes and ducts. Smoke, Fire and Volume Control. The DG door transfer grilles are designed for use in doors where constant air transfer with non-vision is required. recent projects include: Harrow Crown Courts Walton Prison (Segregation. Duct registers, grilles and diffusers shall be installed in accordance with the manufacturer’s instructions. 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. NV3 Grille. Gilberts (Blackpool) Limited is one of the UK’s leading designers and manufacturers of Grilles, Diffusers, Louvres, Smoke/Fire Dampers and Natural Ventilation Systems for the Heating, Ventilating and Air Conditioning industry. Minimum size is 6" x 4" (152 x 102). Item number: 35013002. Long throw, high capacity supply grille with rotating drum. Can be used to provide resistance to fire and hot smoke of up to 60 minutes in doors and walls. NV2 is a Vision proof core in 32mm flanged border. Recommended price. Curtain Rails Collapsible rails and safety track Curtain Tracking Avoid gaps in fixed tracking Curtain Wires Avoid use of curtain wiresThe Advanced Air Model Series 51DG Door Transfer/Non-Vision Grilles are designed to meet the demand for top quality andcompetitive prices. SCHAKO sight-proof transfer grilles are overflow grilles for walls and doors and are used between two adjacent rooms for pressure compensation. 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. It adjusts to suit a door thickness from 1-3/8" to 1-7/8". Fisher & Paykel 48" Grill with Infrared Sear Burner, Natural Gas - BE1-48RCI-N. Discover our wide range of products within the Door grilles category and benefit from 20+ years of expertise Personal advice Competitive prices. 006. co. TROX Easy Product Finder Fast. Product SA - Search A-Z Find out quickly and simply. 4 Dimensional Data Hole - 4mm dia. New Build Residential sales:. Product 36 New Style Intumescent Block Grille. View Products. Air movement in a building is important. Lattice and perforated security grilles reduce the risk of damage and disassembly associated with traditional grilles in secure areas. Jet diffusers. Introduction Gilberts AV1601 Series presents an attractive alternative to traditional vision proof door mounting air transfer grilles. Transfer Grilles offer the largest free area possible with the option of a sight-proof or light-proof core. 8 m 2), the closet door shall be undercut a minimum of 1. ft. dimensions: 788 x 788 mm H • Fitting dimensions: 7 mm more than the grille dimensions. Because transfer grilles connect two rooms or a room and a hallway, there is nothing that is blocking sound between the two areas. frame: telescopic frame suitable for doors or partitions from 25 – 55 mm thickness (fixed on both sides of the door) material: extruded aluminium profile for frame and blades: sizes:Above door transfer grilles. Canadian iron main entrance doors gate grill design single door $35. Introduction Gilberts FB Series provides a compact, efficient range of intumescent fire dampers designed to satisfy all types of air transfer application in offices, shops, schools, hospitals and many other commercial projects. 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. Static Pressure 100. application in offices, shops, schools, hospitals and many<br />. 002 0. When mounted into a door, our telescopic frame can facilitate a door thickness between 28 and 52mm, with light tight or vision proof cores to meet the application requirement. 2. Length : 80 mm. Certifire approved. Ventilation grille with angled blades. 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. Ideal for low velocity air handling systems, it can be operated as a stand-alone unit. Click here to download. <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. If at hallways, then, they are a code violation nowadays, as door grilles are not fire rated, there may some rated doors with grilles, but it is your case? 2. TheBareHandyman • 2 yr. Download. Program. View Product. CERTIFICATIONS. Even more important is the operation of these systems, particularly mechanical and plumbing. 001. 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. Bespoke designs, priority order and guaranteed delivery dates. In the event of an alarm condition, or power failure, the smoke shutters shut, preventing the passage of cold smoke. e. • Height in 85 mm steps (blade pitch) • Door thickness: from 37. Domestic Warm Air Heating Grilles. Still family owned Gilberts operates from its 120,000 sq ft manufacturing base in Blackpool, Lancashire with an annual turnover in excess of £20 million. £7. H Nominal grille heigh t. Submit a request online and get a quote from your local representative within 4 hours. Install the Air Transfer Grille into the aperture. Private conversations and loud noises can easily be. 6") HVAC OV 17. From standard grilles and registers, to its architectural line of Formations® linear slot diffusers, along with a newly released series of displacement. Individual grilles, grille bands, multiple grilles, and long throw nozzle grilles achieve different throw distances. 0 ( 0) From £4. Download catalogue. Displacement diffusers. 020 inch water column) is acceptable for rooms with a design airflow ≥150 cfm. 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. My 1st choice would be jumper ducts for aesthetics and better air volume capabilities. Their special features make them ideal for placing in doorways and interior walls. Supplied in two pieces it lends itself to easy installation in a standard 44mm thick fire door, + when finished with a colour co-ordinated edge flange, results in an attractive but efficient air transfer feature. Non-Vision Transfer Grilles Single & Double CoresType DTG/WTG Core Only. Install the Pyroplex Fire. Easy to assemble. 51DG, 61DG. Private conversations and loud noises can easily be. GILBERTS Head Office and Works GILBERTS (BLACKPOOL) LTD Gilair Works, Clifton Road, Blackpool. 9 Slimline Weather Louvre AWLS 37 1. Supplied in 2. TRH (Transfer grilles) 1. Door, Wall or Partition Mounting. It's annoying that you can hear everything that goes on in the house due to the transfer grilles above the door. 200. pattern: vision proof inverted ‘v’ shape horizontal cross section blades arranged to overlap each other. View Product. ft. How tall was Gilles Gilbert? Gilles Gilbert. Optional equipment and. We are the world's oldest manufacturer of decorative metal grilles. Type NV6 Vision proof flanged grille suitable for surface mounting onto doors, wall or partitions. It should not beSupply grille of horizontal-vertical double deflection with air flow regulation incorporated_RTHV . ) Nominal Size Core Velocity (fpm) 100 150 200 250 300 350 400 Velocity Pressure (in. SG-PS. TYPE GPS4 & GPP4 -Air supply or extract grille fascia for applications using a seperate plenum box. A fire-rated version is also available. The units, which satisfy BS 476 Part 22, incorporate intumescent elements which expand and carbonise when exposed to temperatures in excess of 150 C, thereby sealing off the ventilation opening. robustly fabricated from 20swg mild steel and comprises of<br />. The range is available with a wide variety of frame and fixing options to suit various design needs. Designed for wall or partition mounting. Door Transfer Grilles. Our intumescent grilles and fire dampers combine air movement with fire protection. The sight–proof blade configuration and unobtrusive appearance make Krueger’s 600/5600 series grille an ideal choice for wall or door air transfer from room to room. Nailor 51DG and 61DG Series Door Grilles are designed to be. Description. Door Furniture; Drawers and Drawer Runners; Eyes; Feet; Fixings Fasteners; Formed Section; Gastronorm Containers; Gates; Glass Canopy; Handles. ) Ak Factor Core Velocity Velocity Pressure Neg. 6. 3. We are also able to custom fabricate products to suit your specific architectural requirements. The Waterloo adjustable, single and double deflection grilles are suitable for duct, ceiling and sidewall applications in most commercial projects. A range of grille sizes can be produced from two modules of size 150mm by 150mm and 225mm by 112mm each 40mm thick. SG-SD. There are no doors - just an open stairway leading to the cold air return upstairs? I'm considering converting one of the transfer grille to a cold air return if needed - although hoping I don't need to do the extra work if not needed! Attachments. Grilles are available in a range of sizes and offer up to 60 minutes integrity in accordance with BS 476-22. Du ctodamp esl v ni 7. 005 150. Supply and extract grilles for all building types including double and single deflection grilles, egg crate cores, security grilles and data centre floor grilles. Blades are chevron in configreation and are mounted in a fixed position ina rigid PVC track in an integral part of the frame. Est. A transfer grille or grate is a panel or fitting with an opening allowing air or sound to move from one room to another. Non-vision air transfer grilles, made of aluminium, withRETURN GRILLE DOOR/TRANSFER GRILLES MODELS: DG-I, DG-2, DG-3 DG-I CORE ONLY 11/16" 5/16" DG-2 Single Flange SUSTATNABLE EXTRUDED ALUMINUM Dimensions are in inches (mm) a DG-I Core only Door Transfer Glille a DG-2 Single Flange Door Transfer Glille a DG-3 Double Flange Door Transfer Glille OPTIONS: 11/16". IP£X grille rating that provides an open area of 23%. Conditioned air supply sized to deliver at a rate equal to 1 cubic foot per minute (0. 61DGD - Steel • Double Flange. NV4: Slimline surface mounted with a non-chevron blade, designed to suit fire doors. A range. Heavy Duty Registers and Grilles. Available in nominal 2" (51) increments. The sight–proof blade configuration and unobtrusive appearance make Krueger’s 600/5600 series grille an ideal choice for wall or door air transfer from room to room. ALN, ALM, ALF, ALG, ALJ Airline Linear Grilles 14 APF, APG, APJ, APN, APM Plasterline Linear Grilles 16 UC / UF / UE Urban Grilles 17 Door / Sidewall Grilles NS, DV, NSNL Air Transfer Grilles 18 DSR, DSRX Acoustic Air Transfer Grilles 19 T P W Ss e l l i r G l l a w e d i 20 WFV, WFVG Fire Rated Air Transfer Grilles 21 Floor GrillesWaterloo transfer Grilles are suitable for mounting in doors, partitions and Walls to allow ventilation air to pass between adjacent rooms. Intumescent air transfer grilles to satisfy air transfer application in doors. 0 ( 0) From £45. For both fire and smoke protection, see the Lorient LVN20S Air Transfer Grille. Allows for air transfer through doors or walls. Grilles are optional and supplied by. Coat Hook Remove all hooks behind doors, in wardrobes, etc. Designed to be fitted in doors, walls and ducts they provide a cost effective solution in allowing free air movement and yet maintain the integrity of the door or wall in a fire situation. ) Nominal Size Core Velocity (fpm) 100 150 200 250 300 350 400 Velocity Pressure (in. ago. This may cause the damper to scream. Vision proof. Jet diffusers.