The credit intent is to, Provide for the effective delivery and mixing of fresh air to support the safety, comfort and well-being of the occupants. We will demonstrate our compliance through the second compliance by submitting a detailed narrative illustrating the design approaches that were used per the ASHRAE Fundamentals Handbook 2001, Chapter 32: Space Air Diffusion, as described in the edition of the Reference Guide (May 2003 edition). We understand from the Reference Guide that in the case of an audit we must provide scale airflow pattern diagrams, among other data, on all major room types. We would like verification of our interpretation of the major room types of our project and our approach to meeting the credit intent. Our major room types are defined on the basis of room size, shape, extent of mechanical recirculation, the location of heat generating objects, and air motion. We have determined that 5 room types can represent the majority of the regularly occupied rooms at the health center. 1) 100 ft2, 4 ACH 2) 100 ft2, 12 ACH 3) 170 ft2, 4 ACH 4) 170 ft2, 9 ACH 5) 400 ft2, 4 ACH All room types above have 1 diffuser in the center of the room, except for room type 5, which has 2 diffusers Assumptions: - tests will be completed in cooling mode because we do not have air-based in-room heating - radiant panels located at the perimeter walls and will negate exterior wall effects - furnishings are neglected because they are minimal in offices and patient rooms and based on literature, will not contribute significantly to our ADPI calculations Hospital rooms, such as operating rooms, requiring specialized ventilation systems are excluded from our testing. These systems are characterized by high air change rates and laminar flow outlets. We feel that the high air change rate is sufficient to achieve the required ventilation effectiveness. Further, this system type cannot be evaluated using ASHRAE's Standard 113. We have also excluded non-regularly-occupied spaces such as corridors, storage rooms etc. as defined in credits EQc8 We have also excluded non-typical rooms from the testing process because they are not major spaces. However, ADPI calculations will still be performed on these rooms as per ASHRAE Fundamentals Handbook 2001, Chapter 32: Space Air Diffusion. For each of the 5 major room types, we will provide the following, as per the May 2003 version of the Reference Guide and the : 1. the predicted ADPI as determined by mock ups in accordance with ASHRAE Standard 113; 2. scale diagrams graphically illustrating the air throw patterns and air directions in the test planes. 3. ACE _cooling calculations per the USGBC ruling dated July 19, 2004 Because of the large variety of rooms we are representing, we cannot provide section and plan drawings showing inlets, outlets, furniture and occupants, as requested. Based on preliminary tests we expect that the test results will support our predicted ADPI. We feel that we will sufficiently demonstrate that the intent of this credit has been met by: 1) following the design recommendations in ASHRAE Fundamentals, Chapter 32; 2) evaluating the ADPI and ACE for all regularly occupied spaces as per the calculation guidelines provided in that document and ASHRAE 62 2001; and, 3) supporting the ADPI calculations with measured ADPI values and scale graphic airflow illustrations at two sections each for the 5 major room types described, We propose to base the design on test results acquired during the design phase. The test results will be submitted, as described above, to demonstrate that the design meets the credit intent to provide for the effective delivery and mixing of fresh air to support the safety, comfort and well-being of building occupants. Please advise us whether this approach is acceptable.
The course of action proposed by the applicant is above and beyond what is required. Per the EQc2 ruling dated 7/19/2004, provided the HVAC design has been developed according to Chapter 32, Table 4, ADPI Selection Guide, for an estimated ADPI of at least 80%, one may use the Zone Air Distribution Effectiveness, Ez, , in ASHRAE Standard 62-2001, Addendum n, Table 6.2, to identify the ACE for each zone." This does not require testing to establish the estimated ADPI. Measured values and graphic airflow illustrations are not needed. Since the heating is not air-based, the heating mode need not be considered if heating occurs in the zone during occupied hours. The EQc2 ruling dated 7/19/2004 provides guidance and useful examples of how to use the ACE calculation procedure once the minimum ADPI of 80% has been established; it also illustrates how to average the ACE for heating and cooling. The establishment of major room types is a reasonable way to approach the calculations. In addition to the major room types given, other regularly occupied rooms such as waiting rooms and operating rooms should be addressed. Contrary to your statement, ASHRAE Standard 113 may be used to measure ADPI of operating rooms as the scope of this test method says that the method is applicable to all types of supply outlets. Furthermore as stated in the EQc2 ruling dated 7/19/2004, the ADPI need not be measured but may be estimated from Table 4 in Chapter 32 of the ASHRAE Handbook of Fundamentals. Please note that higher ventilation rates do not correlate with better mixing of the ventilation air. Higher ventilation rates (ach) will reduce the air change effectiveness, because at these higher ventilation rates the residence time (age) of the air is lower, so there is less time to mix the air.
Related Addenda (Corrections & Interpretations)