Can You Clean Out A Kitchen Exhaust Duct
Kitchen Exhaust Retrofit Duct Guide
Telescopic
Provide spot exhaust ventilation over the stove that vents to the to exhaust steam, cooking pollutants, smoke, and odors to the outside of the home.
- Replace an existing recirculation kitchen fan with a kitchen exhaust fan that is ducted to the exterior or
- Install a new kitchen exhaust fan that is ducted to the outside.
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- Choose a kitchen exhaust fan that will attain air period, audio, and pollutant removal goals.
- Follow manufacturer's installation instructions.
- Apply a metal duct with a smooth interior, equally required past lawmaking.
- Use the duct size recommended past the manufacturer to maximize air flow.
- Make up one's mind the shortest, well-nigh directly route in which y'all can install the duct to run from the unit of measurement to the outside.
- Finish the duct at the exterior wall or roof; install a hooded termination vent with a damper and screening to keep out pests. Wink and seal around the duct terminus.
- Seal all seams and joints in the duct and seal the duct-fan connection with mastic or UL-181 record.
- Provide make-upwards air to the kitchen if the kitchen exhaust fan flow rate exceeds 400 cfm.
- Have the flow charge per unit third-party tested and confirmed.
For more information run across the Pre-Retrofit Cess of Ventilation Systems.
See the Compliance Tab for related codes and standards requirements and criteria to run across national programs such as DOE's Zero Energy Ready Home plan, Free energy STAR Certified Homes, and EPA Indoor airPLUS.
Description
Kitchen frazzle ventilation, properly ducted to the outside, is an essential component of expert indoor air quality (Figure 1). Research has identified kitchens every bit the principal location where about harmful pollutants are generated in the home. During the cooking process, wet and pollutants are released into the home, from the cooking fuel source and from the ingredients themselves. The health effects of cooking pollutants (such as particulate affair, formaldehyde, and NO2) are well established. A helpful summary of enquiry on this event is published past the California Air Resources Board. In addition to decision-making pollutants, the control of odors and moisture from cooking is some other important aspect of adequate indoor air quality in homes. Compounding the issue of pollutants is the fact that kitchens are i of the most popular places to assemble in the dwelling, which increases occupants' exposure to cooking pollutants and increases carbon dioxide levels in the kitchen.
Many kitchens do not have adequate ventilation systems installed. Common kitchen ventilation scenarios one is likely to run across in existing homes include the post-obit:
- Recirculating Mechanical Ventilation
- Many of the existing fans located in kitchen range hoods, downdraft systems, and integrated into over-the-range microwaves are recirculating fans, not frazzle fans that are ducted to the outside. Recirculating fans do not provide ventilation that is compliant with mod codes.
- Natural Ventilation
- Many older homes have no mechanical ventilation but instead rely on natural ventilation via an openable window.
- Fan on Ceiling or Wall
- A kitchen exhaust fan that is located in a general location such as on a wall or on the ceiling away from the stove will non capture and remove kitchen pollutants equally effectively as a range hood fan located directly over the cooktop, even if that ceiling or wall exhaust fan is ducted to the outside.
- Fan Ducted to Attic or Crawlspace
- Ducted exhaust fans that stop in an attic or crawl space are non compliant with code and can cause moisture problems and re-innovate pollutants into the living space.
When ducted to the exterior, mechanical kitchen ventilation systems tin can significantly reduce exposure to cooking pollutants, but while this is considered best practice, because codes practice not crave it, the practice is non commonly seen in older homes. A 2022 study was conducted of tightly constructed homes without range hoods (Militello et al. 2022). The homes in the written report "relied on ventilator exhaust grilles [full general ceiling or wall exhaust fans] in the kitchen area to remove the pollutants. This strategy, in full general, did not prove to be effective. The particulate emissions from cooking overwhelmed any exhaust removal and spread to the rest of the business firm" (Militello et al. 2022). The combination of ducting and using a range hood rather than an area kitchen exhaust fan will reduce kitchen pollutants in any home.
Farther, studies evidence that the majority of residents don't operate their range hoods routinely, or as designed, to properly ventilate the space during the cooking process, often citing the operation of their kitchen exhaust system equally also loud. A homeowner survey of kitchen exhaust use by Lawrence Berkeley National Lab found that noise was one of the about mutual reasons that residents did not apply their kitchen exhaust organization (xx.7%) and many did non consider kitchen exhaust to be necessary (47.7%) (Mullet et al. 2022). Adding an outdoor duct every bit a retrofit application will not only improve indoor air quality by reducing exposure to cooking pollutants but may besides come with additional benefits such equally significantly reducing the operating noise, making occupants more likely to utilize the fan. Even with older fans with higher sone ratings, adding ducting to the exterior can significantly lower noise levels.
Even though adding a kitchen exhaust duct can make such an impact on indoor air quality and dissonance, the conversion is rarely done in existing homes, except as part of a major kitchen renovation. When the retrofit is performed, ducting kitchen ventilation to the outside in an existing domicile is ofttimes done by an electrician, general contractor, or handyman. If part of a broader kitchen renovation, it may be done past a kitchen remodeler or an HVAC contractor. It is of import to ensure that the scope of installing a kitchen exhaust duct is broadly considered. Missing important installation considerations and steps can result in a ventilation organization with inadequate air menses or inadequate capture efficiency. Capture efficiency is measured every bit the percentage of emissions captured and vented to a command device. Until recently, this was a largely ignored area of performance in kitchen frazzle, but manufacturers are beginning to market their fans' functioning related to capture efficiency.
At that place are multiple of import things to accept into account when scoping out the project, including whether you are converting or replacing the existing organisation or installing a new system, and where and what type of fan system to install, as well as where and what blazon of duct to install. These volition be described in the following sections.
Converting or Replacing Existing Recirculation System
If a recirculating arrangement is installed, there are a few things to consider. In many cases these fans tin exist configured to operate as a recirculation fan or an exhaust fan. However, some tin can just exist operated as recirculation fans. Check the fan's ability to operate equally an exhaust fan. Refer to manufacturer installation instructions if available or search online. If you intend to reconfigure a recirculating fan for utilize as an frazzle fan, check to see if it is capable of pulling the required amount of air. It may be necessary to have an energy inspect or other assessment to determine this information unless the contractor installing the range hood tin test the fan.
Fifty-fifty if the existing recirculating fan can be converted to a ducted frazzle fan, the homeowner may still wish to install a new exhaust fan to attain better operation, including higher energy efficiency and quieter operation. Kitchen fans can become coated with grease and grime over time that decreases performance and is difficult to clean off. When looking for a new fan, await for models that are Energy STAR rated.
Note: A mutual scenario for wall-mounted chimney range hoods is to wait as though they are ducted when the flue is really simply for aesthetics and is not connected to any duct organization (Figure 2). Check behind the chimney slice to see whether a duct is fastened to the range hood.
Installing a New Kitchen Exhaust System
When installing a new ducted kitchen exhaust fan, the layout of the kitchen will determine the type of unit that can exist installed. If in that location are cabinets above the range, an under-cabinet range hood is appropriate. For kitchens with open space above the range, a wall-mounted range hood is likely the best selection. For ranges on an island, a ceiling-mounted hood would exist platonic.
Follow the manufacturer'southward installation instructions for range hood placement to maximize capture efficiency. The minimum acceptable catamenia is 100 cubic feet per minute (CFM) when operating intermittently, or v air changes per 60 minutes (ACH), based on kitchen volume, according to ASHRAE 62.2-2019. Code minimums are also established in the 2022 International Residential Code (IRC), Section 1505.iv.4. The Home Ventilating Institute (HVI) provides a diversity of fan size recommendations based on system location and configuration. Current Free energy STAR criteria require that exhaust fans take a minimum efficiency of 2.eight CFM/Watt and a maximum audio rating of 2.0 Sones. Check to meet if the system has been tested for capture efficiency.
Range Hood Arrangement Requirements
Frazzle hoods installed over domestic open-top broiler units should be made of metallic and have a 1/4-inch clearance betwixt the hood and the underside of combustible material or cabinets. The hood should extend the full width and depth of the cooktop, discharge to the outside, and take a backdraft damper (2018 IRC- Section M1505.2.1). Check the manufacturer-included damper to make sure that it is closed. An additional or substitute damper may be necessary. A range hood, fan-integrated microwave, or downdraft system may be selected, simply be conscientious to examine the performance features of these options, as not all options will provide equivalent removal of pollutants. If reconfiguring an existing unit, remove the existing unit from the wall and follow the manufacturer'due south instructions for reconfiguring from a recirculation fan to an exhaust fan. Note that this may involve electrical work, depending on existing wiring. A qualified installer should perform any electrical alterations. When replacing an older recirculating fan with a new organization, it is possible that wiring volition need to be changed to adapt modern controls. The older arrangement may only accept had an on/off switch while a newer organisation may be variable speed, requiring dissimilar wiring details. Discover data on certified fan products at hvi.org.
Duct Textile
The duct serving the range hood should be made of rigid metal such as galvanized steel or stainless steel and should have a smoothen interior surface. Metal or plastic flex ducts are prohibited. This is a mutual code violation related to kitchen exhaust systems. PVC ducts may exist used for downdraft exhaust systems.
Duct Size
To ensure the duct is correctly sized, refer to the manufacturer's installation instructions for duct size. The larger the duct, the less it will restrict air flow. Using a duct that is too minor for the required air flow will significantly reduce the achieved menses rate. To achieve the rated air flow of the selected fan, the right duct size is needed. The size recommended by the manufacturer will vary by model and sometimes past exit direction (horizontal or vertical duct). Depending on the exit option selected, an exhaust arrangement may crave a circular or rectangular duct. For example, a range hood might use a 6-in. round duct or an equivalent 3.25 x x-in. rectangular duct. Ducts can be transitioned from rectangular to round via connector pieces. Cut openings in the ceiling or wall for the exhaust duct no wider than needed to fit the duct and whatever needed insulation. An opening that is likewise small will not let installation of the duct. An opening that is besides large will complicate air sealing measures and may require additional supports.
Duct Get out Route, Layout, and Complications
Locate the shortest, most straight route to the exterior in which the appropriate duct size can fit, taking into account any obstacles and complying with termination location requirements. This varies depending on the location of the equipment and the floor plan of the dwelling house. Ducts should not exist combined with other duct systems. Frequently complications arise that prevent a complete direct route. Choose a route that non simply minimizes duct length, but likewise limits elbows in the duct run. Longer ducts and more elbows will reduce menses rate, sometimes to the point where a fan with a college rated CFM must exist considered. Elbows non but reduce flow but can allow the build upwards of grease over time. Many fan models take the power to duct from the summit or from the back of the unit to better suit duct runs that could go vertical or horizontal.
Longer duct runs will need to be supported co-ordinate to code. Depending on the lawmaking adopted, the code may refer to the duct manufacturer's instructions or to a maximum of 10-foot intervals. The fact that the ducts are metal volition prevent sagging between supports only duct supports may be necessary if the run is longer than 10 feet (see 2018 IRC M1601.four.iv).
Interior Wall Complications
If the equipment is located against an interior wall, the shortest route may exist through the attic (typical in a one-story house). For 2-story homes with the kitchen on the first floor on an interior wall, often this means running the duct upward and through cabinets to the exterior. If a duct is passing through finished space to reach the exterior, it could run through an available floor cavity if joists are running parallel to the duct. If non, a soffit should exist considered. Review the maximum length guidelines specified in the current local building code. The shortest run possible is ideal.
Kitchen Island Range Complications
A kitchen island range often encounters similar exit route complications to that of an interior wall. For ceiling-mounted isle range hoods, the most straight route may be through the roof. For a downdraft system, the duct would need to run through the floor joists to the outside or through a soffit in the story below.
Exterior Wall Complications
If the equipment is located on an outside wall, ducting to the exterior can be simpler, only sometimes structural members are obstacles to direct routes to the outside.
Example Scenario: A kitchen range is located on an exterior forest-framed wall. This wall has a stud directly in the center of the range, blocking the shortest, straightest exhaust duct run. Duct elbows could be used to twist the duct around the stud to achieve the exterior, resulting in a less-than-ideal duct installation with reduced air flow. Or, the contractor may be able to cut out a portion of the stud to allow the duct to pass through, then install framing pieces above and below to transfer the load to surrounding studs.
Duct Termination
Vent the kitchen fan frazzle to the outside, non into an attic, crawlspace, or space betwixt floors. Terminating the duct within the dwelling house violates lawmaking and volition introduce wet and kitchen pollution into the indoor environment. The frazzle duct must vent outside and the terminal cease of the duct must exist a minimum of ten feet away or three anxiety higher up any air inlet and at least 3 feet away from whatsoever operable window (see 2022 IRC, Section M1504.3). Additionally, the fan cannot exhaust air onto walkways, a common scenario for townhome communities (see 2022 IRC, Section R303.5.2).
Instance Scenario: A kitchen on an exterior wall had a range installed immediately side by side to an operable window during a previous kitchen renovation. An frazzle duct installed to a higher place the range direct through the exterior wall will exhaust too close to the window, violating lawmaking and allowing odors and kitchen pollutants to re-enter the infinite when the window is open. A solution may be to route the duct vertically through the roof or at least high enough on the wall to terminate at least three feet from the window. Another solution might be to convert the window to a department of solid wall.
The penetration in the exterior building envelope must be flashed to foreclose the intrusion of bulk wet and must be sealed with caulk, foam, or a gasket to prevent air leakage through the edifice envelope. The duct termination must be covered with louvers, a screen, or a grille to protect the exhaust duct from weather and pests. The EPA Indoor airPLUS plan requires a pest screen at exhaust terminations. Duct terminations should be integrated aesthetically with the exterior cladding. Installations of kitchen exhaust ducts ofttimes do not take into account how to integrate the duct termination with the exterior cladding, resulting in a termination grille that is but screwed on meridian of the exterior siding. Planning the installation of cladding finishing pieces as office of the work will help avert an eyesore at the cease of the project.
Duct Sealing and Insulation
All duct joints and seams must be sealed with either mastic or UL 181 tape. Failure to seal the seams will upshot in duct leakage and reduced air period. In some cases, duct leakage may likewise result in unwanted condensation in the dwelling house. Warm moist air from a kitchen exhaust system leaking into cold spaces will cause surface condensation. Careful sealing of all possible points of leakage volition forestall major performance issues on the frazzle duct. Connect the exhaust duct to the fan box with mechanical fasteners and seal with mastic or UL 181 tape. Air seal any holes in the fan box with mastic or UL 181 tape.
Although duct insulation is non required for exhaust ducts, for ducts passing through unconditioned infinite in colder climates duct insulation is recommended to forbid condensation. All penetrations created for the duct should have into account the width of any planned insulation to avoid crushing or compressing the insulation.
Make-Up Air
For homes with combustion appliances, it is important to provide make-up air to prevent hazardous atmospheric condition in which the range hood exhaust fan causes the combustion appliance to backdraft. The 2022 IRC, Section M1503.6, requires that if the range hood is capable of exhausting more than 400 CFM of air, make-up air must be provided. This only applies in homes with gas appliances that are atmospherically vented. This is a combustion safety issue. For homes adding a kitchen exhaust fan for the commencement time, if a ≥400 CFM exhaust system is installed, this requirement will utilize, if there are any atmospherically vented combustion appliances in the home. Annotation that in earlier versions of the IRC, this requirement applies to all homes with ≥400 CFM kitchen exhaust systems, regardless of whether there are combustion appliances in the home.
Although 400 CFM is the code trigger for brand-up air requirements, make-up air should be considered even for kitchen exhaust fans with lower CFM ratings. In a home with atmospherically vented combustion appliances, it is possible for a range hood to crusade back-drafting fifty-fifty when pulling less than 400 CFM of air flow (run into Figure four). If the home has combustion appliances, consider adding make-up air regardless of the range hood'due south rated CFM.
The IRC allows multiple options for providing make-up air. The makeup air can exist provided mechanically or naturally straight to the kitchen, to a room that communicates with the kitchen, or to a duct system that communicates with the kitchen. This last option is the near common because it allows the introduction of brand-upwards air into the dwelling house'south HVAC duct system, which prevents unconditioned outdoor air from beingness straight introduced into the infinite.
A damper is required for the make-up air inlet. Although the code allows this to exist a gravity damper, a mechanical damper is preferred. Gravity dampers are not tested to any standard and are oftentimes field made. It is conceivable that backdrafting could occur at pressures depression enough that a gravity damper would non be forced open by the exhaust system.
Verification
The exhaust fan flow rate should be tested by a certified free energy rater using test procedures listed in ANSI/RESNET/ICC 380-2016.
Ensuring Success
- Each habitation will bring its own fix of variables. Be prepared to conform to site atmospheric condition and obstacles. Before beginning all piece of work, map out multiple possible paths to the outdoors, paying close attending to structural barriers and allowable termination points. Consider that scope may be significantly broader than installing duct for a new abode or complete kitchen renovation.
- Follow the manufacturer's instructions for duct sizing and connecting the duct to the exhaust fan. In order for the fan to perform equally expected, the correct sized duct and connection must exist installed. A unlike sized duct will adjust the performance of the kitchen ventilation arrangement.
- Follow the manufacturer's instructions regarding the location to install the kitchen ventilation system. Heart the unit over the range. Hoods should extend the whole width of the range top. Pay close attending to the recommended summit the ventilation unit should be above the range top. The location of the organisation in relation to the range top plays a critical role in maximizing capture efficiency (the percentage of emissions captured and vented to a command device).
- See the Compliance Tab for requirements for To a higher place Code Programs (Free energy STAR Certified New Dwelling and DOE Goose egg Energy Ready Home), ASHRAE 62.two- 2022 Standards, and Building Lawmaking requirements (IRC and IECC). Be certain to check your local code for whatever additional requirements.
- Air seal all ducts and ostend the frazzle duct is sealed to the fan box with both mechanical fasteners and mastic and/or metallic tape. Seal all penetrations to the exterior with caulk or spray cream.
- Ensure the duct is properly sealed using UL 181 tape or mastic to seal all joints and seams. Mastic is preferable.
- Afterward installation, take a certified rater or energy auditor verify performance by conducting a catamenia hood exam using ANSI/RESNET/ICC 380-2019.
- See the Success Tab in the Solution Center guide Kitchen Exhaust Fans for new homes for further guidance and more considerations to ensure a successful installation.
Climate
Consider insulating the frazzle duct in cold climates to avoid condensation on the duct.
The Compliance tab contains both program and code data. Code language is excerpted and summarized beneath. For exact code language, refer to the applicable lawmaking, which may crave purchase from the publisher. While we continually update our database, links may have changed since posting. Please contact our webmaster if y'all notice cleaved links.
Free energy STAR Certified Homes, Version iii/3.1 (Rev. 09)
National Rater Field Checklist
Heating Ventilation Air-conditioning (HVAC) System.
7. Whole-House Mechanical Ventilation System.
7.four Arrangement fan rated ≤ 3 sones if intermittent and ≤ 1 sone if continuous, or exempted.44
eight. Local Mechanical Exhaust - In each kitchen and bath, a arrangement is installed that exhausts directly to the outdoors and meets one of the following Rater-measured airflow and manufacturer-rated sound level standards:42, 48
Footnote 42) The whole-firm ventilation air flow and local exhaust air flows shall be determined and documented past a Rater using the same version of ANSI / RESNET / ICC Std. 380 that is utilized by RESNET for HERS ratings.
Footnote 44) Whole-house mechanical ventilation fans shall exist rated for audio at no less than the airflow charge per unit in Item ii.3 of the National HVAC Design Report. Fans exempted from this requirement include HVAC air handler fans, remote-mounted fans, and intermittent fans rated ≥ 400 CFM. To be considered for this exemption, a remote-mounted fan must be mounted outside the habitable spaces, bathrooms, toilets, and hallways and there shall be ≥ four ft. ductwork betwixt the fan and intake grill. Per ASHRAE 62.ii-2010, habitable spaces are intended for continual homo occupancy; such space generally includes areas used for living, sleeping, dining, and cooking simply does non generally include bathrooms, toilets, hallways, storage areas, closets, or utility rooms.
Footnote 48) Continuous bathroom local mechanical frazzle fans shall be rated for sound at no less than the airflow rate in Item 8.2. Intermittent bath and both intermittent and continuous kitchen local mechanical exhaust fans are recommended, but not required, to be rated for sound at no less than the airflow rate in Items 8.1 and 8.ii. Per ASHRAE 62.2-2010, an exhaust system is one or more fans that remove air from the edifice, causing outdoor air to enter past ventilation inlets or normal leakage paths through the building envelope (e.g., bathroom exhaust fans, range hoods, clothes dryers). Per ASHRAE 62.two-2010, a bathroom is any room containing a bathtub, shower, spa, or similar source of moisture.
Footnote 49) An intermittent mechanical exhaust system, where provided, shall be designed to operate equally needed by the occupant. Control devices shall not impede occupant command in intermittent systems.
Footnote fifty) Kitchen volume shall be adamant by cartoon the smallest possible rectangle on the floor plan that encompasses all cabinets, pantries, islands, peninsulas, ranges / ovens, and the kitchen exhaust fan, and multiplying past the average ceiling height for this surface area. In addition, the continuous kitchen exhaust rate shall be ≥ 25 CFM, per 2009 IRC Table M1507.3, regardless of the rate calculated using the kitchen book. Chiffonier volume shall be included in the kitchen book.
DOE Zero Energy Ready Domicile (Revision 07)
Exhibit ane Mandatory Requirements.
Exhibit ane, Item 1) Certified under the Free energy STAR Qualified Homes Plan or the ENERGY STAR Multifamily New Construction Program.
Exhibit 1, Item half-dozen) Certified under EPA Indoor airPLUS.
2012, 2022, and 2018 International Energy Conservation Code (IECC)
2021 IECC Table R402.iv.i.1 (2018, 2022, 2022 IECC – Aforementioned Reference)
Mandatory Table R402.4.1.1 requires all penetrations in the air barrier, and all duct penetrations to the exterior to be sealed.
Retrofit: 2009, 2022, 2022, 2022, and 2022 IECC
Section R101.4.three (in 2009 and 2022). Additions, alterations, renovations, or repairs shall adapt to the provisions of this code, without requiring the unaltered portions of the existing building to comply with this code. (See code for boosted requirements and exceptions.)
Chapter 5 (in 2022, 2022, 2022). The provisions of this chapter shall control the alteration, repair, addition, and change of occupancy of existing buildings and structures.
2009, 2022, 2022, 2018, and 2022 International Residential Code (IRC)
2021 and 2022 IRC M1503.3 (2015, 2022 IRC, 2009 IRC – M1503.ane)
The IRC requires that a habitation has a kitchen exhaust system that is ducted to the outdoors. However, it includes a big exception that allows homes to use natural ventilation (e.g. windows) along with a recirculating mechanical kitchen ventilation system. For this reason, a large number of existing homes do non take an existing duct to the outdoors for use in a kitchen ventilation system.
This section likewise requires that the duct system exist closed and have a polish interior. The requirement for a shine interior eliminates all flex ducts from compliance. It is important to notation that flex ducts are commonly used for kitchen exhaust retrofits for their ease of installation, merely this exercise violates lawmaking.
Ducts serving kitchen exhaust systems are not permitted to terminate anywhere inside the building. This includes a prohibition of the common practice of terminating the duct in a ventilated attic or crawl space.
2021 and 2022 IRC M1503.four (2015 IRC, 2022 IRC, 2009 IRC – M1503.2)
Kitchen frazzle ducts must be fabricated of specific material. For virtually kitchen exhaust systems, the just allowable materials are metallic (galvanized or stainless steel, or copper). Aluminum ducts, a common flex duct material, are not allowed. The simply exception to the metal duct requirement applies to downdraft systems, which are immune to apply Schedule forty PVC.
2021 and 2022 IRC M1503.half-dozen (2015 IRC, 2022 IRC, 2009 IRC – M1503.four)
If the range hood is capable of exhausting more 400 CFM of air, make-up air must be provided. This only applies in homes with gas appliances that are atmospherically vented. This is a combustion safety issue. For homes adding a kitchen frazzle duct for the first time, if a high-CFM system is installed, this requirement will apply. Notation that in the 2009, 2022, and 2022 IRC, this section applies to all homes with 400 CFM+ kitchen frazzle systems regardless of fuel blazon.
2021 and 2022 IRC Table M1504.two (2015 IRC – Table M1506.ii)
This table sets the maximum duct length for any exhaust ducts. The tabular array varies based on type of duct, duct diameter, and rated CFM of the frazzle fan. At that place is an exception that allows the apply of a manufacturer design with site-tested and confirmed flow. Note that this tabular array was added in the 2022 IRC and did not exist in previous versions.
2021 and 2022 IRC M1504.3 (2015 IRC – M1506.3; 2022 IRC – M1506.ii)
For all exhaust openings, in that location are specific limitations to their location. They must be at to the lowest degree iii feet from other openings such as windows and doors, or gravity intakes. They must be at least x anxiety abroad, or 3 feet higher up intakes for mechanical supply. This is a complication for near kitchen exhaust duct retrofit projects. There is often a window close to the ideal location for kitchen exhaust because the firm was designed to use windows for natural ventilation in combination with a recirculating range hood. This department was added in 2022.
2021 and 2022 IRC M1505.4.iv (2015 IRC, 2022 IRC – M1507.4; 2009 IRC – M1507.3)
This section provides a table with requirements for kitchen exhaust systems to encounter a minimum flow charge per unit. The exhaust can either be at least 100 CFM, when operating intermittently, or 25 CFM, when operating continuously, to see the minimum requirements. Fans replacing existing exhaust systems, exhaust systems replacing recirculating systems, or new installations of kitchen frazzle systems would all be required to run across this minimum menstruation rate. This department provides a blueprint target and does not require field verification for code compliance.
2021 and 2022 IRC M1601.iv (2015 IRC, 2022 IRC, 2009 IRC – Aforementioned Reference)
Joints and seams in exhaust ducts must be sealed according to this department, which lists a variety of adequate materials for sealing. While many sealing methods are permissible according to code, mastic remains the most reliable for preventing air flow leakage.
2021 and 2022 IRC M1601.4.iv (2015 IRC – Same Reference; 2022 IRC, 2009 IRC – M1601.4.3)
In the 2022 and 2022 IRC, ducts are required to exist supported according to manufacturer's instructions. The 2022 and 2009 IRC prescribe duct support intervals not to exceed ten feet. The 2022 and 2009 IRC also crave ½-inch-wide 18-approximate straps or 12-judge galvanized wire.
2021 and 2022 IRC R303.5.2 (2015 IRC, 2022 IRC, 2009 IRC – Same Reference)
In add-on to the locations prohibited in M1504.3, R303.5.two specifically prohibits exhausting onto walkways.
2021 and 2022 IRC R303.six (2015 IRC, 2022 IRC, 2009 IRC – Same Reference)
Describes protection requirements for ventilation openings including protection from location-specific weather.
Retrofit: 2009, 2022, 2022, 2022, and 2022 IRC
Section R102.7.i Additions, alterations, or repairs. Additions, alterations, renovations, or repairs shall conform to the provisions of this code, without requiring the unaltered portions of the existing edifice to comply with the requirements of this lawmaking, unless otherwise stated. (Meet code for additional requirements and exceptions.)
Appendix J regulates the repair, renovation, alteration, and reconstruction of existing buildings and is intended to encourage their continued condom utilise.
ASHRAE 62.2-2019 Ventilation and Adequate Indoor Air Quality in Residential Buildings
Any jurisdiction or voluntary program that requires ASHRAE 62.2 besides requires that kitchen frazzle exist ducted to the outside. While this typically applies to new construction, existing homes programs such equally the Weatherization Assistance Program, require ASHRAE 62.ii in order to safeguard against causing problems by making existing homes more efficient only increasing indoor air quality risk.
ASRHAE 62.2 section 5.iv requires that exhaust fans have a site measured menstruation rate. Exceptions to this measurement including using manufacturer design criteria, or using prescriptive duct sizing table v-3. This table tin only be used for ducts less than 25 anxiety in length, with less than three elbows. Duct size, length, and the number of elbows will all accept an effect on both the achieved CFM of the exhaust system and the racket level. Tabular array 5-two sets minimum flow rates for local exhaust, including kitchen exhaust Minimum air menstruum for kitchen exhaust is 100 CFM operating intermittently or v ACH (based on volume) operating continuously.
Admission to some references may crave buy from the publisher. While we continually update our database, links may have changed since posting. Please contact our webmaster if you find cleaved links.
References and Resources*
*For non-dated media, such as websites, the date listed is the date accessed.
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