ASHRAE_Guideline_0-2019_ - Page 053
Extracted Content
(This appendix is not part of this guideline. It is merely informative and does not contain requirements necessary for conformance to the guideline.)
INFORMATIVE APPENDIX N QUALITY-BASED SAMPLING EXAMPLES
This appendix provides an example of how to implement part of Guideline 0. It is not intended to be a comprehensive representation or a best-practice example. Practitioners applying the Cx should carefully follow Guideline 0 and applicable commissioning technical guidelines tailored to their specific projects.
N1. DESIGN PHASE SUBMISSIONS
A critical step in the Cx is the review of the design submissions from the design professionals. It is important to remember that the role of the CxP is to verify that the OPR is met and that the system is designed in a quality manner. There are three distinct reviews that are completed on a drawing set: general, coordination, and field specific. A review of the specifications is also required. The general steps of completing a drawing review are as follows.
N1.1 General Review
a. Review the OPR. Because the drawing review is to verify
that the OPR is met, prior to the review the OPR should be reviewed to familiarize the reviewer with the key criteria of the facility. b. Document the General Review Criteria. The criteria
from which to accomplish the general review of the submission must be documented. The criteria should be based on general quality characteristics and specific OPR criteria. The general quality characteristics should include items such as the following:
- Continuation of items (ductwork, pipes, etc.) from page to page
- Labeling, including correct room numbering
- Details corresponding to actual components
- Schedules, including BoD information
- All information legible (not hidden by crossing lines or text)
- OPR information is included on drawings c. Accomplish Quick General Review. The general review
is intended to familiarize the reviewer with the submission. If, during this review, significant items are identified as of poor quality, then the review process should be stopped and the design professionals contacted to discuss the quality concerns. If the general quality is good, move on to the coordination review.
N1.2 Coordination Review
a. Determine Sampling Areas. For each floor plan area (i.e.,
if there are five sheets for each floor, then there are five floor plan areas for each floor) select a single 10 × 10 in. (250 × 250 mm) square randomly. A simple way to do this is to divide the drawing sheet into 15 squares (5 × 3) and select square number 3 on the first sheet (area) and then 5,
7, etc., for each remaining area. This selection is accomplished typically using the architectural sheets. b. Select Review Samples on Drawings. Using the sam pling strategy chosen in Step 1, mark the sample areas to be reviewed in each area. This should be accomplished for each trade (landscaping, architectural, structural, plumbing, mechanical, electrical, etc.). c. Accomplish Coordination Review. For each area, com pare the squares between each discipline. The intent of this review is to identify coordination problems with the placement and installation of components. Items of specific interest include the following:
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Placement of multiple pieces of equipment/components in the same location
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Accessibility to equipment/components for maintenance/replacement
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Use of consistent terminology (e.g., room numbers)
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Elevations provided where multiple systems are placed in the same area
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Other trade duties clearly identified (e.g., electric wiring for HVAC equipment, holes for sinks)
If significant coordination problems are identified, stop the review and contact the design professionals to discuss. If the coordination is good, continue on with the field-specific review.
N1.3 Field-Specific Review
a. Determine the Review Sampling Procedure. Use ran dom sampling that selects every x th square on the drawings to be verified. Squares that are completely blank (no walls, equipment, etc.) are not included in the counting. For example, if there are 10 pages of drawings and each drawing is split into 15 grids (5 × 3), there will be 150 potential grids to review. If a 20% sample rate is desired, then 30 grids would be reviewed, or every 5 grids. The starting grid should be chosen using a random selection process (die, 1 through 6 in a hat, etc.). b. Document Review Criteria. The criteria from which to
review the drawings should be based on specific OPR criteria. These typically include items such as accessibility, maintainability, meeting sustainability goals, comfort conditions, documentation of OPR and BoD, and operating details. c. Select Review Samples on Drawings. Using the sam pling strategy chosen in Step 1, mark the sample areas to be reviewed. d. Accomplish Detailed Statistical Review. Using the
review criteria from Step 2 and the selections from Step 3, conduct a detailed review of the drawings. This includes verifying that the specifications match those shown on the drawings (see below for specification review details). For example, if a VAV box is in the selected square, the steps in accomplishing the detailed review might include the following:
- Review design calculation inputs for matching architectural assumptions and the OPR.
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