ASHRAE_Guideline_0-2019_ - Page 054
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- Compare calculation results with the total airflow of the diffusers downstream of the VAV box and with the VAV box schedule.
- Compare location of VAV box with maintenance requirements of the selected make and model (BoD).
- Compare VAV box location on drawings with requirements in the specifications.
- Review the OPR for other issues that the VAV box could impact. e. Document Concerns. During the review of the drawings
keep detailed notes of problems found or concerns with certain items. Also, at the end of the review, a general summary of the quality of the drawings should be developed. A letter detailing the quality of the drawings should then be sent to the design professionals and the Owner with specific recommendations and directions given. f. Review the Drawing Review Procedure. After the drawing review is completed, this document should be reviewed and modified to improve the process for the next time.
N1.4 Specification Review
a. Determine the Review Sampling Procedure. The pur pose of this review is to determine the general quality of the specifications. During the field-specific review, the actual details are checked. The sampling procedure should check approximately 10% of the specifications. The easiest way of doing this is to check every x th page of the specifications (i.e., if there are 100 pages, check every 10th page). b. Accomplish General Review. The review should focus
on the quality of the specification, specifically as follows:
- Are there extraneous sections that do not pertain to the project (i.e., medical gas in an office building, 15 types of valves when only two are used, etc.)?
- If a manufacturer has been listed, has the engineer checked to verify that the OPR is met?
- Are there any “or as equals”? (“As equal” should always be defined.)
- Are the directions clear and concise? c. Develop Summary of Review. Develop a summary of the
review. If there are problems with the specifications, contact the design professionals and discuss.
N1.5 Design Professional Actions. Comments provided by the CxP should be formally replied to by the design professionals. If systemic issues are identified during the CxP’s review, the design process should be stopped and the issues resolved. It is expected at the next submission that the CxP will again use random sampling that will result in a review of different areas on the drawings and the specifications, and that will identify whether the systemic issue has been resolved. Back-checking of the specific items may be appropriate, but not as the sole means of verifying resolution of the issue.
N2. CONTRACTOR PHASE SUBMISSIONS
The focus of the review of contractor submittals by the CxP during construction is different from that accomplished by the
design professional. Whereas the design professional reviews all submittals against the contract documents (specifications), the CxP compares a sample (typically 5% to 10%) of a submittal against the OPR and BoD. This different approach is due to the fact that the Cx role is to verify achievement of the OPR using quality tools.
The following are general guidelines for implementing quality-based sampling on contractor submittals:
a. Submittal Received. Verify submittal falls within Cx
scope. b. Select Sample for Review
- Single/Few (<10) Components. Choose every x th part of the submittal—for example, for a 10 page submittal, to get a 10% sample, divide each page into 6 parts and select every 10th block (resulting in 6 blocks to check).
- Multiple Components. Choose every y th component (typically 20% to 30% of components) and then divide and select blocks as detailed above for “Single/Few (<10) Components.” c. Accomplish Review. For each sample block, review
information contained against the OPR and BoD. Identify discontinuities. d. Results. Document results of the review. Typically, if
consistent issues are identified, the general quality of the submittal to achieve the OPR is lacking, and the recommendation provided to the design professional should be to reject the submittal. In the CxP write-up, it is important to state that a sampling approach was used to avoid having the design professional or others assume that the CxP reviewed everything.
N3. CONSTRUCTION PHASE TESTS AND VERIFICATIONS
The role of accomplishing site visits and Cx tests is the ongoing verification of OPR achievement. Because the contractor is responsible for 100% construction and checking of work, the Cx uses a sampling strategy in accomplishing verifications and tests.
a. Construction Checklist Verifications. During site visits,
the completed construction checklists are verified (typically 2% to 10%). The following is general guidance for selecting and verifying construction checklists.
- Identify Completed Construction Checklists. Identify the construction checklists that have been completed since the last site visit.
- Select Sample. Depending on the pace of construction and the size of the project, the number of new construction checklists can vary widely. The following is a general guide for sample rates based on the number of new construction checklists. Please note that this is not meant to be used directly for your project due to the many variables in determining acceptable sample rates and Owner input. Randomly select the construction checklists to be verified. Note that you often want to sample similar components as a group so that if there is only 1 or 2 of a particular component, it is not
52 ASHRAE Guideline 0-2019