This credit requires compliance with a varied group of items that cumulatively help keep pollutants out of the indoor air. These requirements include self-closing doors on janitors' closets, MERVMinimum Efficiency Reporting Value (MERV) rating is an American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) measurement scale which rates the effectiveness of air filters. 13 filtration on mechanical equipment, and entryway trackoff systems.
Compliance will require the coordination of team members—including the mechanical engineer, architect, plumbing engineer, and contractor—and also impact project design and operations. The basic requirements are:
In addition to tobacco smoke, covered in IEQp2, one of the greatest sources of indoor pollutants is the dirt and other contaminants brought into buildings on people’s shoes. This material is tracked through the building interior, increasing the need and frequency for cleaning, and the wear on interior finishes. Dust can also be introduced into ventilation systems and distributed throughout a building, negatively effecting indoor air quality.
While it takes a lot of coordination to meet the many credit requirements, this is generally a low-cost credit. The most significant impact may come if MERVMinimum Efficiency Reporting Value (MERV) rating is an American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) measurement scale which rates the effectiveness of air filters. 13-compatible air-handling equipment is not initially specified, as redesigning mechanical systems can be costly. In some situations, especially when using heat pumps, HVAC systems cannot accept MERV 13 filters because they are not able to draw air through such a thick filter.
MERV 13 filtration results in an energy-use trade-off. While MERV 13 filters offer a greater level of air filtration and, consequently, increased indoor air quality, they also increase resistance to airflow and fan energy loads. If you can separate space conditioning from ventilation and use radiant systems for all or most of the space conditioning, you can minimize this energy penalty.
Multifamily residential and hotel projects may have difficulty achieving this credit due to the MERVMinimum Efficiency Reporting Value (MERV) rating is an American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) measurement scale which rates the effectiveness of air filters. 13 filtration requirement. These projects often do not have base-building HVAC systems; they use PTACs instead, which generally cannot be fitted with MERV 13 filters. If a project has forced air systems and MERV-13 filtration is not used, then you cannot pursue or achieve this credit. Naturally ventilated buildings do not have to meet the MERV 13 filtration requirement, as air filtration will not be part of system design.
When LEED 2009 was launched, this credit included language calling for containment drains in laboratory spaces where chemicals are mixed. However, the requirement was vague and it wasn't clear how to document it. Fortunately, in the July 2010 LEED addenda issued by USGBC, this requirement was removed.
There is no definitive information from USGBC on this one way or another. It is recommended that project teams do their best to find low-emitting options for IEQc5, and that IEQc4.3 compliance is recommended.
However, LEEDuser has heard that project teams have had success not including track-off mats, such as the type with grilles and small strips of carpeting. Also, mats that are removed for cleaning are not permanently installed and thus not subject to credit requirements. If used as track-off surfaces, carpet tiles should be certified, however, and are available with the requisite certifications.
There is not an official glossary definition that LEEDuser is aware of. However, various references indicate that LEED views "high volume" as one or more printers in an area totaling more than 40,000 copies (20,000 double sided) per month. The number is based on "expected" use, not capacity. This definition can be found in LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. #1938 issued 1/7/2008, for example, and although that Interpretation is not applicable to LEED 2009, the number 40,000 has appeared in enough places that we view it as a solid number.
If the copiers print less than 40,000 pages/month (20,000 pages double-sided) you do not need to install dedicated exhaust, self-closing doors and deck-to-deck partitions. Additionally, if you use printers that do not emit VOC’s or other harmful contaminants into the indoor environment, you can make a case for exemption.
LEED Interpretation #10098, dated 8/1/2011, states that "The intent for the entryway system (grilles, grates, walk-off mats) is to capture dirt and dust. An exception to the 10 foot length and/or indoor location is acceptable provided your alternative solution meets this intent and is thoroughly justified."
Project teams have been successful including exterior mats that are protected from the weather and regularly cleaned. LEEDuser has not heard of a project successfully gaining an exception to the 10-foot requirement, however. In situations where an irregular shaped mat makes sense, teams should consider whether people entering the building will travel at least 10 feet over a mat, and not be able to short-circuit it. A short narrative explaining the impediments and how your solution meets the standard established by the LEED Interpretation is recommended.
These entrances are those that are used by building occupants on a regular basis. If your project has unique circumstances where certain building entrances are not regularly used or do not serve building occupants, they may be excluded. For example, emergency exits that are not used as regular entrances can often be excluded.
LEED Interpretation #5266 made on 05/30/2007 states that the requirements are applicable only to entrances from the outdoors.
Yes, carpet tile applies per LEED Interpretation Ruling #10252. Some project teams have preferred to use carpet tile due to ease of maintenance and avoidance of trip hazards. The carpet tile must be specifically designed for entryway systems. Regular carpeting that is not designed for this purpose and does not have regular cleaning is not applicable.
LEEDuser has not seen an official ruling on this, but our expert consensus is no.
One, replacing a physical control with a policy control is a bit of a downgrade. Two, 100% avoidance of hazardous chemicals in cleaning is unlikely. The green cleaning purchasing credit in EBOM, for example, considers 30% good enough to earn the credit. Also, the thresholds, categories, and standards referenced in that credit will only go so far in preventing use of any cleaning supplies that might generate gases or chemicals that should be exhausted.
Identify programming requirements for special-use spaces such as high-volume copy rooms (40,000 pages or more per month), laboratories, art rooms, chemical storage, housekeeping areas, and other spaces that may expose occupants to hazardous materials.
Identify space requirements for entryway walk-off mats. Review the impact that the required ten-foot entryway systems will have on common areas, lobbies, and other interior spaces adjacent to building entries. Remember that the entryway systems have to be installed at all regularly used entrances from exterior spaces, including entrances from a covered parking garage into the building.
The LEED Reference Guide states that entryway systems need to be on the interior of the building or in an interior vestibule. It is recommended that projects pursuing this credit with the intent of using an exterior entryway system (either permanent or rollout) consult the GBCI or your certification board via email to verify credit compliance. It is usually accepted that exterior walk-off systems are allowed if they are properly sheltered from weather; that would typically mean some kind of roof, but additional shelter may be warranted depending on local conditions.
Review the potential for using MERV 13 filtration on ventilation systems. Systems with low fan power or filtration size limits may not be able to accommodate MERV 13 filters. Also, many residential and hotel projects use PTACs, or similar packaged systems, which cannot accommodate MERV 13 filters. Any mechanical ventilation must be designed with MERV 13 filters in mind.
If you can use radiant heating and cooling for space conditioning and separate that function from ventilation, you’ll be moving a lot less air and meeting the MERV 13 requirement won’t be nearly as big a deal, due to fewer and smaller ducts and filters.
Include mechanical engineers and design consultants for special-use spaces such as science labs early in the design process.
This is usually a low-cost credit. However, the MERV 13 filtration requirement can increase operational costs for added energy use and more frequent filter changes. If your ventilation system is not typically sized to accommodate a MERV 13 filter, you may have to choose a new system or have one custom-designed, which can add cost. Customization may include resizing ductwork, increasing fan capacity to maintain air delivery despite the added resistance of MERV 13 filtration, or other modifications to system design.
Design an adequate space for ten-foot entryway systems at all regularly accessed building entries. Evaluate all other building entrances—such as employee and service doors—for regular use, which may require entryway systems or roll-out mats.
Determine the type of entryway system that's best for your project. If you install permanent grates, grilles, or slotted entry systems, you will not be required to have a plan for cleaning, although those systems will still need periodic cleaning (less frequently than roll-off mats). However, if you decide to use rollout mats, you'll need to have a contract in place for weekly cleaning. The contract for weekly cleaning can be incorporated into any existing contract but must be clearly spelled out.
While roll-off mats are acceptable, additional documentation (service contracts and schedules) is required to confirm that the mats will be cleaned on a weekly basis. They cost more up-front, but permanent entryway systems provide better performance, require less maintenance, and are easier to document for LEED compliance.
Entryway systems should be climate-specific. For example, regions with high rainfall may choose high void-volume mats—for trapping dirt below the mat surface and fast drying. In regions where mud and snow are a greater source of contaminants, open-loop entry mats may be more appropriate.
Design in space for additional ductwork that might be needed to provide designated exhaust for all garages, high-volume copy rooms, janitors’ closets, science labs, workshops, art rooms, or any other spaces that may be used for mixing and storage of chemicals or hazardous materials. You need to design the exhaust system so that each space with hazardous material has negative pressure in respect to adjacent spaces. For each of these spaces, be sure to include self-closing doors, and deck-to-deck partitions or hard-lid ceilings.
Strategies for space planning may include:
When planning for space allocation to meet credit requirements, consider strategies like merging exhaust systems into a single, main, designated exhaust, or stacking chemical use areas over each other on different floors to minimize ductwork.
Provide adequate space for storage and containment of hazardous liquids.
Hazardous storage containers should be located in a secure area outdoors and away from air intakes.
Develop an outline of all the IEQc5 requirements that apply to your project, and confirm that the schematic design accommodates each one.
Adding ductwork to meet credit requirements can add costs; incorporate space-planning strategies to minimize this issue.
Once programming and space allocations have been determined, confirm that each of the relevant credit requirements is met, as detailed below.
Confirm that all mechanical ventilation systems can accommodate MERV 13 filtration on outdoor and make-up air supply.
If roll-out mats are used, make selections appropriate to the climate. The following specifics are also recommended in the LEED Reference Guide:
Confirm that chemical disposal areas meet local codes for separate drain lines or containment drains.
Confirm that all chemical storage areas, high-volume copy rooms, etc. have:
Locate hazardous waste storage containers away from outdoor air intakes.
Develop all required documentation for LEED submittal, including floor plans indicating locations and lengths of entryway systems, wall details (for deck-to-deck partitions), mechanical drawings showing locations of designated exhaust systems, and mechanical schedules specifying MERV 13 filtration.
For all spaces that may contain hazardous gas (such as garages, janitors' closets, and labs), calculate exhaust rates to confirm adequate negative pressurization. The pressurization requirements are:
Include credit requirements in all appropriate specification sections. Include the general requirements in Division 1 and others in specialties or furnishings (for the entryway systems) and HVAC (for filtration and other mechanical requirements).
Projects that use their own maintenance staff for regular cleaning of rollout entryway systems must provide a cleaning schedule and narrative along with their documentation.
Develop documentation customized for LEED submission—complete with LEED-related notes, callouts, and details—concurrently with the finalized construction documents.
The contractor is the signatory for IEQc5, even though it's a design credit. Have the contractor review 100% of the construction documents to confirm compliance before completing the design submittal. Otherwise, the credit may have to be deferred until the construction submittal.
Use temporary ventilation systems instead of the permanent HVAC units during construction. This prevents contamination of new ductwork during the construction process.
Use MERV 8 filtration on any permanent mechanical system equipment used during construction. This adds to construction management tasks and could easily be overlooked and lead to loss of the credit. (This requirement appears in the LEED Online credit form as of 10/09, even though it does not appear in the credit language or LEED Reference Guide.)
Make sure that compliance and coordination with this credit is called out in the IAQ management plan if your project is pursuing IEQc3.1: Construction Indoor Air Quality Management Plan—During Construction.
Ventilation and exhaust systems and proper filtration should be included in the commissioning scope for the commissioning credits EAp1 and EAc3.
Provide appropriate training for maintaining entryway systems. If roll-out mats are used, maintain a weekly schedule for cleaning.
Provide adequate training and education for all O&M and cleaning staff in appropriate handling, use, storage, and disposal of hazardous liquids.
Provide appropriate resources and training for O&M personnel to maintain mechanical equipment with MERV 13 filters.
Mechanical systems have to be commissioned to meet the commissioning prerequisite EAp1. The commissioning agent's scope should include confirming appropriate MERV ratings on filtration media and proper operation of designated exhaust systems.
Excerpted from LEED 2009 for New Construction and Major Renovations
To minimize building occupant exposure to potentially hazardous particulates and chemical pollutants.
Design to minimize and control the entry of pollutants into buildings and later cross-contamination of regularly occupied areas through the following strategies:
Projects in East Asia may use filtration media classified as high efficiency (高中效过滤器) or higher as defined by Chinese standard GB/T 14295-2008 (空气过滤器).
Design facility cleaning and maintenance areas with isolated exhaust systems for contaminants. Maintain physical isolation from the rest of the regularly occupied areas of the building. Install permanent architectural entryway systems such as grills or grates to prevent occupant-borne contaminants from entering the building. Install high-level filtration systems in air handling units processing both return air and outside supply air. Ensure that air handling units can accommodate required filter sizes and pressure drops.
This updated version of the spreadsheet categories dozens of specific space types according to how they should be applied under various IEQ credits. This document is essential if you have questions about how various unique space types should be treated. Up to date, 2nd Edition.
This spreadsheet categories dozens of specific space types according to how they should be applied under various IEQ credits. This document is essential if you have questions about how various unique space types should be treated. This is the 1st edition.
The Janitorial Products Pollution Prevention Project is a governmental and nonprofit project that provides fact sheets, tools, and links.
According to the website, IAQIndoor air quality: The quality and attributes of indoor air affecting the health and comfort building occupants. IAQ encompasses available fresh air, contaminant levels, acoustics and noise levels, lighting quality, and other factors. Design Tools for Schools “provides both detailed guidance as well as links to other information resources to help design new schools as well as repair, renovate, and maintain existing facilities. Though its primary focus is on indoor air quality, it is also intended to encourage school districts to embrace the concept of designing High Performance Schools, an integrated, whole building approach to addressing a myriad of important—and sometimes competing—priorities, such as energy efficiency, indoor air quality, daylighting, materials efficiency, and safety, and doing so in the context of tight budgets and limited staff."
Environmental Building News feature article describing the benefits and design choices for entryway walk-off systems.
Environmental Building News feature article explaining the various types of air filters, how their performance is measured, and ways to optimize their effectiveness.
Facilitiesnet article covering the basics of air filtration, drawbacks and benefits, standard practices and basic concepts.
Table of filtration efficiencies and their subsequent filtration properties and common applications. Good background on MERVMinimum Efficiency Reporting Value (MERV) rating is an American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) measurement scale which rates the effectiveness of air filters. 13 filtration.
This is a sample cutsheet for a MERVMinimum Efficiency Reporting Value (MERV) rating is an American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) measurement scale which rates the effectiveness of air filters. 13 filter that demonstrates compliance with credit requirements.
These plans from a LEED-certified project demonstrate how to design and document a hard-lid ceiling in a janitor's closet for credit compliance.
A floor plan like this project example is required to document the presence of entryway track-off systems, length and location. Note that this sample shows six-foot entryway systems because the project predated LEED 2009. For LEED 2009, the systems need to be ten feet in length.
Sample LEED Online forms for all rating systems and versions are available on the USGBC website.
Documentation for this credit can be part of a Design Phase submittal.
The conference center I'm working on has several small meeting rooms that have interior and exterior doors with the exterior doors leading to open public terraces. Those exterior doors are usually used by people taking a fresh air break from a meeting then coming back into the rooms. There are primary doors into the conference center nearby. Do those exterior secondary doors need walk-off mats?
You have to consider 2 things: exterior-to-interior, and regularly used. As an "open public terrace" your entrance fits the first criteria. So you would need to justify that the entrance is not a regularly used entry point. The interpretations on this subject are related to loading docks, and not directly applicable, but take a look http://www.usgbc.org/node/1732542?view=interpretations&return=/credits/n....
Ask yourself how much contamination could be brought into the building by meeting participants taking a break, and whether you think you meet the intent of the credit.
We have two chemical storage rooms that are adjacent to one another and share a common wall. Each of these spaces will have its own exhaust. We were wondering if it would be acceptable to have the deck-to-deck partitions create a border around the outermost perimeter of both rooms rather than have each room have full deck-to-deck partitions along all four walls. This strategy would separate the rooms containing chemical from the rest of the building, but the shared wall between the chemical storage rooms would not have a full deck-to-deck partition. Thanks.
I believe this solution would be acceptable. The intent of the deck to deck requirement is to separate the areas containing hazardous chemicals and toxins from the other areas of the building. I know you mentioned the independent exhaustion, just be sure they are negatively pressurized and you've included self-closers on the doors of both rooms.
I agree that seems like a reasonable strategy. Make sure you document clearly what you are doing and how it meets the intent.
In order to meet EQc5 requirements, do science prep rooms have to be independently exhausted even if fume hoods are installed (given deck to deck partitions and self-closing doors are present as well)? Thank you!
To determine the answer to this question ask:
Are all the potential indoor pollutants housed in the fume hoods? If you have a separate chemical storage area, or if chemicals are ever in the room outside the hood, they would also need negative pressure and exhaust.
Are the fume hoods on whenever a potential pollutant is inside the hood (sealed or unsealed) during occupied hours?
If you can justify that occupants are protected by your design from potential exposure, clearly document your strategy and rationale.
In our Project we can't apply deck-to-deck partitions in some janitor rooms so we are looking for (hard-lid ceiling) option. Can you please advise requirements of this type of ceiling?
The requirements are performance requirements, rather than specific design requirements. You must meet the intent and requirements of the credit using your professional judgment, such that the room can be completely sealed and isolated, and under negative pressure.
We are working on a project of a shopping mall. The building has a few delivery entrances (on the ground level and underground level) next to the delivery docks. These entrances will be used only by the delivery staff to deliver products to the shops. The question is if these entrances also need to be equipped with entryway walk-off systems? Standard building occupants won't use them. Moreover, delivery carts will be taken via these entrances and so it's not really practicall to install walk-off systems there.
In the underground parking lot there are also elevators for delivery only - do these elevator halls need walk-off mats?
From my experience the LEED reviewer will require mats at all regularly used entrances regardless if they are for occupants or delivery staff members.
Agata - From my experience, you may declare the doors for goods delivery to be "normally-closed" doors, so you will not be required by LEED reviewers to put entry mats.
The vestibule is actually rectangular, but the exterior door is 90 degrees off of the interior door, so the walking path is not straight. The entire vestibule has walkoff carpet tiles and is roughly 10'-3" x 6'-6".
In measuring the walking distance between the two doors (and therefore checking for 10' compliance), I have three options: (1) measure straight diagonal line from (center of) exterior door to (center of) interior door (walking distance = 9'-5"); (2) measure "L-shaped" walking distance from exterior door to interior door, as if only robots use the entrance (walking distance = 12'-9"); or (3) measure the arc length of a curved walking path from exterior door to interior door (walking distance = 10'-1").
Which measuring method is most appropriate?
I assume that you are not planning to change the dimensions of the vestibule. In that case you should show the most reasonable pathway representing actual use that meets the 10' requirement, perhaps giving a range of distance.
That is correct. Dimensions are set. We may be able to move one of the doors over a few inches to gain some path distance but otherwise we are really constrained. I think option 3 (arc from ctr. of door -to- ctr. of door) is the most realistic travel path, so I will add that to the drawings. Thanks
We have had a similar issue arise in a previous project. We were able to pursue this credit via alternative compliance path. We had an entryway system that encompassed an entire angled vestibule at roughly a 45 degree angle. The team was able to demonstrate that while the entryway system wasn't a straight 10', the number of steps and total path traveled would equal the required 10' to meet the credit requirement. We provided a written narrative and a highlighted exhibit demonstrating that the number of steps and total distance traveled would meet the requirement. The reviewer approved for the credit without any issues. Hope that helps and provides an alternative to pursuing the credit.
Thank you, Amari. Can you tell me more about the highlighted exhibit that you used. How deep into it did you go? I don't want to make this a science fair project, but I want to avoid doubt from the reviewer.
Of course! It was really quite simple honestly. We drew a dimension line from the door, then another one to follow the angle and the last one finished to the interior door. It was just three straight lines that included dimensions, following the path that a typical individual would walk. In the narrative, we supplied the data of a person's average stride length then included a description as to how a person would travel in that space, walking with an average stride and provided that total calculated length.
Where is the form for the LPE (Licensed Professional Exemption) to fill out and submit for NC 2009? It seems like the only one I can find is for OM 2009.
Also, what is the more typical path of compliance? LPE or Full Documentation Path? Seems like it may be simpler to just fill out the short pressurization calc and upload the self-closing door documentation than risk disciplinary action against your license if there is an error in the form. I'm sure it's fine either way, but I don't like the wording of the language for the LPE. There should be some kind of requirement of willful intent or neglect for disciplinary action from the board, rather than the wording "incomplete or incorrect".
This is difficult to find and has changed. When logged in to LOL, click on the drop down arrow to the right of your name and click on Credentials. You can add or edit your professional licenses.
Once you do that, there should be a drop down on any credit form that you are in where you can choose your name for LPE.
I'm a fan of LPE whenever you can use it, because it is usually less work, but you're right, you need to use your professional judgment. However, a lot of LEED consultants prefer the full pathway so they have documentation that the proper work was actually done.
As a LEED consultant, I prefer to see the full pathway, because, as Michelle says, that way I know whether the proper work was actually done. In my experience, it often takes more than one try (before we submit to GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC).).
We've heard that per a recent LEED clarification for filtration credit requirements, MERVMinimum Efficiency Reporting Value (MERV) rating is an American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) measurement scale which rates the effectiveness of air filters. 13 filtration is required on ALL outdoor air handling units, not just those serving regularly occupied spacesRegularly occupied spaces are areas where one or more individuals normally spend time (more than one hour per person per day on average) seated or standing as they work, study, or perform other focused activities inside a building. as currently noted in the LEED forms. Is that correct?
MERVMinimum Efficiency Reporting Value (MERV) rating is an American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) measurement scale which rates the effectiveness of air filters. 13 filters are required for all units providing outdoor air to either regularly occupied areas (e.g. offices) and non-regularly occupied areas (e.g. break rooms).
Units providing outdoor to unoccupied areas (e.g. inactive storage) do not require MERV 13 filters granted they do not serve any regularly or non-regularly occupied areas also.
The third bullet of IEQ 5 states the following:
In mechanically ventilated buildings, each ventilation system that supplies outdoor air shall comply with the
– Particle filters or air cleaning devices shall be provided to clean the outdoor air at any location prior to its introduction to occupied spacesOccupied Spaces are defined as enclosed spaces that can accommodate human activities. Occupied spaces are further classified as regularly occupied or non-regularly occupied spaces based on the duration of the occupancy, individual or multi-occupant based on the quantity of occupants, and densely or non-densely occupied spaces based upon the concentration of occupants in the space..
– These filters or devices shall be rated a minimum efficiency reporting value (MERVMinimum Efficiency Reporting Value (MERV) rating is an American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) measurement scale which rates the effectiveness of air filters. ) of 13 or higher in accordance with ASHRAE Standard 52.2.
We have several AHUs (Air handling units) located on the roof of our building, and many FCUs (Fan Coil units) installed and located inside of our building. My understanding of the above is that we have to have MERV 13 filters only for the AHUs as they supplies outdoor air, and not the FCUs. Could someone please confirm?
That is correct. Compliant filters are required on the AHUs, not on the FCUs.
does anybody know if we should consider microbiology laboratory premises as a pollutant source for this credit?
I would. I generally include any type of lab in this credit.
Hmmm... working on Environment & Natural Resources building with "teaching labs" that consist of lecture style arangement of furniture: chairs and tables lined up to face a presentation wall. No sinks, no fume hoods, no storage of chemicals of any kind. Pretty sure this is a classroom labelled "lab" because that word holds more appeal to these students. Guess I'd better clarify this in my narrative.
That sounds like the right approach. The word lab will raise a flag.
I have a laundry room in a building which has no interior doors to other inhabited interior spaces, only an exterior door and exterior windows. A reviewer referred me to an equation in Section 53.5 of the 2011 ASHRAE HVAC Applications Handbook. I have the 2015 Handbook here, and an equation there in Section 53.7, adjusted for units, has the differential pressure in Pascals at the square of CFM of airflow divided by 27552 times the square of the leakage area in SF. To achieve 5 Pa, this means 371.16 CFM per square foot of leakage area. Table 2 lists exterior, stairwell and elevator shaft walls, but not interior walls to other types of spaces. Should I use the exterior wall numbers for interior walls not adjacent to stairwells or elevator shafts? And should I use the loose, average or tight numbers in Table 2?
I've never been asked to do the leakage for the SF of a wall. Just for the door. If you have windows then the window as well. The calculation is typically for the linear feet around the perimeter of the window/door rather than the sqft.
OK, so a reviewer directed me to the 2011 ASHRAE HVAC Applications Handbook. I have the 2015 Handbook, and there in Section 53.7 is an equation which, adjusted for units, has differential Pa at CFM^2 / (27552 * SF^2). There is a Table 2 which lists leakage area ratios for walls and floors. I will assume a ceiling is like to a floor for this purpose. For walls, only exterior, stairwell and elevator shaft walls are listed in this table, and so I find it odd that this whole thing is being used mainly to determine underpressurization wrt an adjacent inhabited space. So should one consider interior walls not adjacent to stairwells or elevator shafts as like to exterior walls, and should one be using the loose, average, or tight ratios?
I am working on a graduate housing project that is all residential, and some apartments have doors directly to the outdoors. What are the walk-off mat alternate requirements in this case? We will provide walk-off mats to all other entries/corridors and it is only a few apartments that will need to meet an alternate compliance path.
My other question is can walk-off mats be an L-shape, such as leading in to a doorway on the right? We are looking into this because part of the corridor is exposed, so we need to push back the walk-off mat. It might not be 10' long unless we can use this L-shape option.
I'm not aware of an alternate compliance path unless you think you can justify LEED Homes criteria below. As for the L-shape, that should be acceptable IF you have 10' along the path of travel including cutting the corner if that is likely.
8.2 Indoor contaminant control (1 point each, maximum 2 points). Select from the following measures:
a. Design and install permanent walk-off mats at each entry that are at least 4 feet in length and allow accessibility for cleaning (e.g., grating with catch basin).
b. Design a shoe removal and storage space near the primary entryway, separated from living areas. This space may not have wall-to-wall carpeting, and it must be large enough to accommodate a bench and at least two pairs of shoes per bedroom.
c. Install a central vacuum system with exhaust to the outdoors. Ensure that the exhaust is not near any ventilation air intake.
Thanks, Michelle. We were also looking into the LEED for Homes requirement. I asked this question to LEED Coach also and apparently individual residences are not considered high traffic areas so we would not have to include walk-off mats!
We are specifying a recessed walk off mat for the building in the vestibule (8' long). I remember that if the walk off mat is 10', a point is granted. Do you know if the walk of mat needs to be recessed, or can we add a loose floor mat just inside the vestibule so the total length would be 8' + 2'? Or does the mat have to be recessed.
That should be fine, but you will need to demonstrate a weekly cleaning contract for the loose mat.
We have a project that has a washer & dryer in the corner of a building services room, for periodic/sporadic use. If the dryer vents directly out of the building (exterior wall) does this resolve the exhaust issue? Or is the requirement for dedicated exhaust actually related to the use of detergents? If the dryer vented outside, and it could be confirmed by the client that they would only use "green" cleaning agents, does this remove the requirements for this credit for this room? It is not clear what the actual issue is with "laundry rooms".
Laundry rooms are on the list due to cleaning supplies and exhaust, so I would say that exhausting the dryer would not be sufficient. If it's a hardship to meet the credit requirements for this project I would argue your case in the special circumstances or submit a CIR, but make sure you aren't storing cleaning supplies (bleach etc) in that room.
In our project, we have a janitor room adjacent to a toilet and these both rooms have exhaust duct which are combined together & exhausted directly to outside without re circulation.
But, we have common a fan coil unit to these rooms (i.e, supply air is going to both rooms & return air is taking from both room). Also,fresh air is provided to these room via FCU (in false ceiling) and both rooms are negatively pressurized.
Our concern is that return air from janitor room is going to FCU & this same FCU is serving toilet also. Will this affect our IEQc5 credit ?
Recirculation is not allowed for this credit.
Why not just duct the return for the fan coil unit into the hallway. Then you wouldn't have the recirculation issue.
For garage spaces that are designed for CO/NO₂ monitoring and have a neutral (Exhaust air – Supply air = 0) pressurization.
Please clarify how the average pressure differential with the surrounding spaces should be calculated.
In this case, you don't under pressure the garage space (often it is open to outside via the ramp, so it's impossible anyway). You must overpressurise the connected spaces so that the calculation of the airflow from a connected space (which is supplied more air than extracted) to the garage across cracks, grills and door undercuts shows a pressure difference as required by LEED. In the construction phase, you could even measure it.
What happens if the printers are situated with the open plan office - not a dedicated room. Does the printer need to be a particular spec ?
Typical desktop printers don't require any special treatment. Printers with 40,000 copies per month or more must be physically isolated in a room with negative pressure relative to surrounding areas per requirements listed in the credit language.
I would like to make sure what does "dedicated/designated exhaust" mean. Can all hazardous gas and chemical use areas have one exhaust system combined with the exhaust from toilets or does every kind of spece (eg. copy rooms, janitor room) have to have a separate system and fan?
Dylan should confirm, but yes you can combine the exhaust with toilets. I'm less certain about whether you can also combine one hazardous/chemical use with another.
Yes you can combine the exhaust systems.
Similar question - does the exhaust need to run 24/7, or can it be shut down when the building is unoccupied to conserve energy?
Just during occupied hours. California's T24 says to start the building's ventilation (and exhaust) 1 hour before occupancy - LEED has no rules with this regard - just best practice.
Do you have any citations for this that I can use for reference in case I get a review comment about it? I have not seen an LI or CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide for it, but I always like to be certain before it's too late to make changes.
Thank you very much, Dylan.
Why Entryway systems are at least 10 feet not 9 or 8?
10 is a proxy for 2 full steps per shoe from an average person. Eg. Left... right... left... right.. off
I always wondered what was magical about 10' as well. I did some looking online to see if there is any research has been done, and found some conducted by a mat manufacturer, but nothing suggesting 10' is optimal. Another site said about 52% of debris on shoes is eliminated in 10' (depending on composition of mat) and 100% in 30'. I'm assuming LEED adopted 10' as a reasonable distance and, as Dylan points out, is typically the distance of 2 full strides. I think the most effective mat is the one that comes with a sign that say "Wipe Your Feet!"....just like mom raised us to do. )
A little history:
Neither LEED versions 2.0 nor 2.1 specified a minimum walk-off distance, but a 2003 LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. dictated, “the length should ensure that all foot traffic will encounter the entryway system.” In 2005, LEEDv2.2 set the minimum length at 6-feet (1.8 m). That was only about enough for “left-right” and little more than what many commercial properties provided for conventional, non-green buildings.
Ultimately, EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating systems.-2008 & LEED-2009 increased the minimum to 10-feet (3 m), presumably for the reason that Dylan cites.
I have seen references that cite various percentages of dirt removal at various distances for various mat types. These numbers may have come from some kind of empirical research, but I have never been able to find a primary source for any of this data. However, it is intuitive that more mat is better than less.
Dylan's wipe each foot twice explanation is the same I have heard from Steve Ashkin.
could you please help me with the following question - on our project we have revolving doors with entryway systems installed, its diameter is 2,8 m. Entering way length through this door seems to be longer that 2,8 meters - i guess it would be approximately 3,5-3,7 m. Do we need to extend our entryway systems up to 3 meters? Will providing a narrative explaining my position work? I'm not quite sure about it, hope anyone could help me. Thanks in advance.
This interpretation should help. It is ok to have your entry within the revolving door if the length is sufficient.
How are people proving the differential pressure of applicable spaces in credit documentation? What tool is being used to determine the pressure differential, obviously not all projects will be doing blower door testing.
They don't actually require you show your work - you just check that you comply. There is an equation you can use to do the calculation for yourself. It is in the comments below.
We have a mixed use building major renovation on a Government site. There are shops and maintenance areas, some that have unique exhaust systems. Our designer has addressed these requirements. There are also a number of meeting rooms, office space of varying size from single senior staff as well as rooms with anywhere from 3 to 30 staff. No contract information was provided regarding walk-off mats or printers. During design, our client provided the following:
1. Our client determined that our recessed walk-off grills should not be longer than 6 ft. To meet the requirement for this credit, can we add 4 ft of roll-off mats?
2. Additionally, the documentation requirements are that we provide the maintenance requirements for the roll-off mats (i.e. a minimum of weekly cleaning). Do we also have to provide documentation from our client that they have a contract to clean the mats weekly?
1. Client indicates they will install low volume, convenience printers in areas designated for office workers supporting shops in our building and other shops in a industrial type area. These printers would be purchased under a separate contract. No further guidance was provided. Our designer has provided suggested locations in his design, providing one convenience printer per every 15-30 desks, but this is not part of his design requirements. The client has approved his design which shows the suggested convenience printer locations. Do we need to wait for the client to purchase printers or use the suggested locations provided in design?
Regarding low-volume printers - no you don't need to wait for them to be purchased. LEED is a design tool and you are indicating your design intentA written document that details the ideas, concepts, and criteria that are determined by the owner to be important to the success of the project. on most credits.
That answer sure does make my life easier, thanks!
I am working on a project in SE Asia. As with many resorts in SE Asia the lobby is sheltered but open to the exterior of the building. Does this count as the building interior or would entry way mats have to be placed at the interior of entrances to fully enclosed spaces?
The intent of the requirement is to remove contaminants from shoes before they are tracked into enclosed spaces and create indoor air quality issues. Typically these need to be inside the building, and precedent indicates that review teams take a quite strict view of the requirement for mats to be inside the building, although limited exceptions are made for renovated buildings.
That said, the regulations were not created with SE Asian architectural design in mind, and depending on the design, location and use of the property it may be possible to convince the review team that the credit intent is satisfied by placing mats at the entrance to the sheltered lobby. For example, It appears unlikely that this solution would be acceptable for an office building lobby in Bangkok where air pollution is high and dust will contaminate the lobby, while it may be acceptable at a remote island hotel where sand should be removed at the building entrance.
In any event, I would recommend submitting a CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide to confirm the strategy if achieving the credit is important to your certification strategy.
LI#5219 addresses an issue similar to yours: http://www.usgbc.org/leed-interpretations?keys=5219. Just as your question suggests, this ruling exempts open-air spaces, but requires walk-off provisions at entries into enclosed spaces.
However, because IEQc5 criteria have changed slightly since LEEDv2.2, portions of this interpretation may not be applicable to LEED-2009. To be safe, you may choose to request an interpretation from the USGBC citing LI#5219 and inquiring how this ruling might apply to your project’s specific conditions.
Did you get any feedback from USGBC regarding this subject? In our project there is a dining room which is connected to an outside terrace. The terrace has a roof and a short surrounding wall and people can access it only from the inside. My case is in some way similar to yours and I would like to confirm if this kind of entrance between the terrace and the dining room need a 10feet long entryway mat?
Balconies accessed only from the interior don't need entryway mats. I would apply that to a terrace as well.
Agata - We had a similar design, a dining room which is connected to an outside terrace. The terrace has an open grid/ trellis roof and a short surrounding wall with trellis. Similar scenario, people can access it only from the inside. However, there are gates for emergency egress. We did not provide a 10feet long entryway mat in this area and were awarded the credit. The USGBC reviewer questioned it, but we indicated these doorways would be exempt from the requirements of this credit as emergency exits or non-regularly used/available building entries.
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