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© Copyright U.S. Green Building Council, Inc. All rights reserved.
Requirements
Design to minimize and control the entry of pollutants into buildings and later cross-contamination of regularly occupied areas through the following strategies:
- Employ permanent entryway systems at least 10 feet (3 meters) long in the primary direction of travel to capture dirt and particulates entering the building at regularly used exterior entrances. Acceptable entryway systems include permanently installed grates, grills and slotted systems that allow for cleaning underneath. Roll-out mats are acceptable only when maintained on a weekly basis by a contracted service organization.
AND
- Minimize the entry of contaminants into the building from vehicles, pesticides, herbicides, helipads, diesel generators, designated smoking areas, sources of exhaust air, and other sources of potential contaminant as follows: Provide pressurized entryway vestibules at high-volume building entrances: Ensure, through the results of mathematical modeling [e.g. Computational Fluid Dynamics (CFD), Gaussian Dispersion Analyses] and/or physical modeling (e.g. wind tunnel, tracer gas) that the air contaminant concentrations at outdoor air intakes are less than the thresholds established for the project under worst case meteorological conditions. Demonstrate that outside air intake concentrations pollutants meet the limits in the following table OR demonstrate by calculations that indoor concentrations shall not exceed 2.5% of the exposure limits listed in the table.
AND
Design to minimize and control cross-contamination of regularly occupied areas:- Where hazardous gases or chemicals may be present or used—garages, soiled utility areas, sterilization and disinfection areas, housekeeping/laundry areas and copying/printing rooms—exhaust each space sufficiently to create negative pressure with respect to adjacent spaces with the doors to the room closed. For each of these spaces, provide self-closing doors and deck-to-deck partitions or a hard-lid ceiling. The exhaust rate shall be at least six air changes per hour with no air re-circulation. (For rooms containing disinfectant and sterilant applications, provide a minimum of 12 air changes per hour.) The pressure differential with the surrounding spaces shall be at least 5 Pa (0.02 inches of water gauge) on average and 1 Pa (0.004 inches of water) at a minimum, when the doors to the rooms are closed.
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See all forum discussions about this credit »Addenda
Our project is using a demand controlled exhaust system for a parking garage to meet the exhaust requirements for Minimum Indoor Air Quality Performance as approved in LEED Interpretation 10247. Is this approach also acceptable to meet the hazardous gases or chemicals requirements in EQ Credit: Indoor Chemical and Pollutant Source Control?
Yes, for parking garages, the demand exhaust strategy determined in EQ Prerequisite Minimum Indoor Air Quality Performance is an acceptable alternative to the exhaust requirements for spaces where hazardous gases or chemicals may be present or used. The other requirements for these spaces must also be met (negative pressure, self-closing doors and deck-to-deck partitions or hard lid ceiling, no air recirculation, pressure differential).
We are meeting the IEQp1: Minimum Indoor Air Quality Performance with Option 2, CEN standards EN 15251:2007 and EN 13779:2007. The CEN standards provide minimum outdoor air requirements for most spaces but refer to local codes for certain specialty spaces such as parking garages. To meet the intent of the prerequisite, we propose using our local code requirements for garages, which is Teil 5 Garagen (“Section 5 – Parking Garages”) of the Verordnung über Bau und Betrieb von Sonderbauten - Nordrhein-Westfalen (“Local Law of North Rhine-Westphalia for the Construction and Operation of Specialty Buildings”), dated 17 November 2009 (SBauVO). To meet this local code, our design will use demand control ventilation with carbon monoxide (CO) detectors to limit the CO concentration. Is this approach acceptable?
**Update 10/01/2014: Ruling has been revised
Yes, garage demand control ventilation is an acceptable ventilation approach for parking garages. This approach is acceptable for projects pursuing Option 2 (EN 15251 and EN 13779) of EQ Prerequisite Minimum Indoor Air Quality Performance as well as the hazardous exhaust requirements in EQ Credit Indoor Chemical and Pollutant Source Control. The demand control ventilation strategy must meet the following requirements:
- • Consider the number of cars expected to be operating in the garage at any given time and the length of time a car remains in operation in the parking garage.
- • Consider the emission rates associated with the car exhaust for the average car.
- • Detect the primary contaminant(s) of concern in the parking garage (for example: carbon monoxide, particulates, VOCs, NO2, etc.).
- • Modulate airflow such that contaminant levels are maintained below a specified contaminant concentration limit and corresponding exposure period. All concentration limits must be based on local code or some other cognizant authority. If the contaminant is carbon monoxide, a concentration limit of 35 ppm time-weighted average (8 hours) and levels not to exceed 50 ppm at any time is recommended.
Where there are physical impediments to locating 10 ft of walk-off mats inside the building, is it acceptable to locate a portion of the mat or grate outside and then the remainder of the required 10 ft inside?
The intent for the entryway system (grilles, grates, walk-off mats) is to capture dirt and dust. An exception to the 10 ft length and/or indoor location is acceptable provided your alternative solution meets this intent and is thoroughly justified. Applicable Internationally.
Carpet tile is not currently considered an acceptable entryway system. One reason carpet tile is not accepted is because it cannot be cleaned underneath and therefore does not meet the performance of mechanical systems (such as grates/grilles), or roll-out mats. Carpet tile is a highly desired material for walk off areas due to its ease of maintenance as compared to mechanical systems, avoidance of trip hazards associated with roll-out mats, and numerous other factors. The ability to clean underneath carpet tile is not necessary. Carpet tile creates a sealed floor where dirt and moisture do not penetrate the seams. Though not specifically required by the rating system, the reference guide provides suggestions for optimal performance attributes for entryway systems. The carpet tile product we are suggesting meets the performance-related attributes as follows:
Capture particles & prevent interior contamination- the carpet tile product is specifically designed to withstand heavy traffic at entranceways. Captures and hides soil, requires minimal maintenance and helps prevent slips and falls. Extend 10 feet: the carpet tile will extend 15' into the interior from the exterior entrance and 40' in left-right directions along the building lobby. Solid backings & appropriate for climate- the carpet tile backing is stable even under extreme changes in temperature and humidity. It will not move, create gaps, or curl up over time. High-void-volume & high fiber height- the carpet tile is produced with needlepunch hair-like face fibers with pile height of 0.165 in. Electrostatic propensity- the electrostatic propensity level is less than 2.5 kV. Weekly cleaning - the walk-off system will be maintained by the in-house school maintenance staff. The tiles are vacuumed daily and spot cleaned with appropriate environmentally-preferable cleaning products as needed. If an individual tile is deemed to be damaged beyond repair, it is simply removed and immediately replaced with a new identical tile.
How can we demonstrate that carpet tile is an equally performing or better solution for entryway systems?
The applicant is requesting confirmation that carpet tiles may be used as acceptable entryway systems. Yes, carpet tiles with similar attributes to the product described are acceptable entryway systems.Conventional carpet is not acceptable, the carpet tile must be specifically designed for entryway system or similar use, have performance attributes equivalent to other acceptable entryway systems, and must be regularly maintained. Applicable Internationally.
***Updated 01/012013 to add applicability for LEED 2009 for Healthcare and to remove the text "(such as high pile height)".
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© Copyright U.S. Green Building Council, Inc. All rights reserved.
Requirements
Design to minimize and control the entry of pollutants into buildings and later cross-contamination of regularly occupied areas through the following strategies:
- Employ permanent entryway systems at least 10 feet (3 meters) long in the primary direction of travel to capture dirt and particulates entering the building at regularly used exterior entrances. Acceptable entryway systems include permanently installed grates, grills and slotted systems that allow for cleaning underneath. Roll-out mats are acceptable only when maintained on a weekly basis by a contracted service organization.
AND
- Minimize the entry of contaminants into the building from vehicles, pesticides, herbicides, helipads, diesel generators, designated smoking areas, sources of exhaust air, and other sources of potential contaminant as follows: Provide pressurized entryway vestibules at high-volume building entrances: Ensure, through the results of mathematical modeling [e.g. Computational Fluid Dynamics (CFD), Gaussian Dispersion Analyses] and/or physical modeling (e.g. wind tunnel, tracer gas) that the air contaminant concentrations at outdoor air intakes are less than the thresholds established for the project under worst case meteorological conditions. Demonstrate that outside air intake concentrations pollutants meet the limits in the following table OR demonstrate by calculations that indoor concentrations shall not exceed 2.5% of the exposure limits listed in the table.
AND
Design to minimize and control cross-contamination of regularly occupied areas:- Where hazardous gases or chemicals may be present or used—garages, soiled utility areas, sterilization and disinfection areas, housekeeping/laundry areas and copying/printing rooms—exhaust each space sufficiently to create negative pressure with respect to adjacent spaces with the doors to the room closed. For each of these spaces, provide self-closing doors and deck-to-deck partitions or a hard-lid ceiling. The exhaust rate shall be at least six air changes per hour with no air re-circulation. (For rooms containing disinfectant and sterilant applications, provide a minimum of 12 air changes per hour.) The pressure differential with the surrounding spaces shall be at least 5 Pa (0.02 inches of water gauge) on average and 1 Pa (0.004 inches of water) at a minimum, when the doors to the rooms are closed.