We have three questions related to compliance with the second part of this Credit's requirements in spaces where chemical use occurs: 1. Our typical strategy involves providing structural deck-to-deck partitions, as well as separate outside exhausting which will create negative pressure. The applicable spaces will not have supply ductwork, but will draw supply air through the small undercut in the door. Does this meet the Credit Requirements for physical isolation of the space? 2. In spaces where chemical use occurs, is it sufficient for the exhaust system to be tied to a switch with a requirement that the user turn it on during the chemical use, or must the exhaust be continuous? 3. A Credit Ruling dated 7/22/2003 included "common laundry rooms" as housekeeping areas where chemical occurs. Laundry rooms typically have both washers and dryers. When a laundry room is in use, the dryers are typically in operation, which draw room air out through their individual exhaust systems. Assuming this measure is submitted under LEED 2.0, will the dryer exhausts meet the requirements for a laundry room, or must the exhaust system be provided in a different manner?
Your inquiry is in regards to a multi-unit residential project. The intent of this credit is to avoid exposure of building occupants to potentially hazardous chemicals that adversely impact air quality. A distinction needs to be made between the chemicals used in residential and commercial projects and the exposure to the occupants, especially in regards to laundry rooms. For example, if a laundry room is anticipated/expected to provide a dual purpose of providing the residents a space for them to do their laundry and possibly an area for custodians or building personnel to clean equipment, e.g. mops, brushes, etc., then as stated in the CIR ruling 7/22/03, the space would have to meet the chemical use requirements under LEED v2.1. Typical residential common laundry rooms do not fall under the category of rooms "where chemical mixing occurs." Additional information can be obtained through the LEED Application Guide for Lodging and it provides guidelines for low-rise lodging facilities. This information can be found on the USGBC website. Below are additional details to the points brought up in this inquiry: 1. The proposed ventilation strategy will not meet the requirements of this credit under LEED v2.1 unless the flow requirements are based on room size and construction. LEED v2.1 has adopted specific negative pressure requirements that must be met. The project team may choose to comply with LEED v2.0 if preferred (mixed submittals are permissible). In that case, the proposed strategy is acceptable because the room does not contain a return vent to the HVAC system. The presence of an HVAC supply duct is permissible as long as the room retains negative pressure. 2. Spaces where chemical use occurs must be continuously exhausted for LEED v2.0 and 2.1. In all probability, chemicals will be present in the room even when active mixing is not occurring and even when the room is unoccupied. In order to meet the intent of this credit, the negative pressure must be maintained at all times. 3. Typical residential common laundry rooms do not fall under the category of rooms "where chemical mixing occurs". Therefore most residential common laundry rooms would not have to be exhausted to meet the intent of this credit. However, if the common laundry room is used as a housekeeping area (with chemical use other than bleach), then an exhaust system separate from the dryer exhaust must be installed to meet the intent of this credit for LEED v2.0 and 2.1. The location of the dryers and relatively low exhaust flow rates from standard operation would not meet the requirements of LEED v2.1. In addition, the exhaust ductwork from individual dryers is positively pressurized. Any lint build-up at the dryer or in the exhaust line will increase the likelihood of recirculation of dryer exhaust into the Laundry space. Finally, similar to the response to item 2, in order to meet the intent of this credit, the negative pressure must be maintained at all times.
Related Addenda (Corrections & Interpretations)