CSI Division
Division 23: Heating, Ventilating, and Air Conditioning (HVAC) submittal deviations
What changes between a Division 23 Heating, Ventilating, and Air Conditioning (HVAC) spec section and the sub's submittal, why it matters, and how each deviation is graded.
Short answer
Division 23 Heating, Ventilating, and Air Conditioning (HVAC) submittals deviate most often on product substitutions, performance ratings, and missing certifications. Deviation Check flags every difference from the spec and grades it a Blocker, Fix and Resubmit, or Note.
Division 23 covers heating, ventilating, and air conditioning systems in commercial construction: air handling units, chillers, boilers, ductwork, piping, controls, and related equipment. Common CSI sections submitted for review:
Common Division 23 CSI sections
Division 23 Heating, Ventilating, and Air Conditioning (HVAC) spec sections frequently submitted for review:
| Section | Title |
|---|---|
23 05 00 | Common Work Results for HVAC |
23 05 53 | Identification for HVAC Piping and Equipment |
23 05 93 | Testing, Adjusting, and Balancing (TAB) for HVAC |
23 07 00 | HVAC Insulation |
23 09 00 | Instrumentation and Control for HVAC |
23 21 13 | Hydronic Piping |
23 23 00 | Refrigerant Piping |
23 31 13 | Metal Ducts |
23 33 00 | Air Duct Accessories (dampers, turning vanes) |
23 34 23 | HVAC Power Ventilators (exhaust fans) |
23 36 00 | Air Terminal Units (VAV boxes) |
23 64 16 | Centrifugal Water Chillers |
23 65 00 | Cooling Towers |
23 72 00 | Air-to-Air Energy Recovery Equipment |
23 73 13 | Modular Indoor Central-Station Air-Handling Units |
23 81 26 | Split-System Air-Conditioners |
23 82 16 | Packaged Rooftop Air-Conditioning Units (RTUs) |
23 83 33 | Ductless Split Units (Mini-Splits) |
The six deviation categories in Division 23 Heating, Ventilating, and Air Conditioning (HVAC)
Every issue Deviation Check flags maps to one of six categories. Here is how each appears in Division 23 Heating, Ventilating, and Air Conditioning (HVAC) submittals, with the full guide one click away.
Manufacturer or Product Substitution
Blocker The submittal proposes a different manufacturer or product than the spec names, without an approved or-equal or substitution request.
HVAC specs routinely name basis-of-design manufacturers (Trane, Carrier, Daikin, York/Johnson Controls, Lennox, McQuay) with model series. Submittals proposing alternate brands must provide "or equal" documentation. Look for:
Performance Specification Gap
Blocker A measurable performance property in the submittal (rating, capacity, tolerance, efficiency) does not meet what the spec requires.
Key performance parameters in HVAC submittals:
Missing Certification or Compliance Documentation
Fix and Resubmit A required listing, test report, certification, or compliance document is absent from the submittal package.
Required certifications in HVAC submittals:
Aesthetic Deviation
Fix and Resubmit A visible attribute (color, finish, texture, profile) differs from the spec or the architect-approved sample.
Less common but applies to:
Aesthetic Deviation in Division 23 Heating, Ventilating, and Air Conditioning (HVAC) submittals →
Detail or Installation Mismatch
Fix and Resubmit The submitted detail, dimension, anchorage, or installation method differs from what the spec or drawings require.
Submittal Package Incompleteness
Fix and Resubmit A required submittal element (cut sheet, schedule, calculation, sample) is missing, leaving the package unreviewable as submitted.
Commonly required items in Div 23 specs:
How Division 23 deviations are graded
Each finding is graded Blocker, Fix and Resubmit, or Note. Division 23 escalation rules:
- Cooling/heating capacity below spec requirement: BLOCKER (system will not meet load; occupant comfort failure, potential code violation)
- Refrigerant type not compliant with local/state regulations: BLOCKER (EPA/state environmental code)
- Missing AHRI certification for equipment with a spec AHRI requirement: BLOCKER (unverified performance claims)
- UL listing absent for fire/smoke dampers (UL 555/555S): BLOCKER (life-safety)
- Duct leakage class exceeds spec: BLOCKER if high-pressure system, FIX_AND_RESUBMIT if low-pressure
- SEER/EER/COP below spec minimum: BLOCKER (energy code non-compliance, Title 24 / ASHRAE 90.1)
- Sound rating exceeds spec NC level: FIX_AND_RESUBMIT for office/classroom, BLOCKER for hospital/recording studio
- Missing seismic certification in seismic zone: BLOCKER (IBC requirement)
- Motor efficiency below NEMA Premium where spec requires: FIX_AND_RESUBMIT (ASHRAE 90.1 compliance)
- Filter MERV rating below spec: FIX_AND_RESUBMIT (IAQ, ASHRAE 62.1)
- Diffuser/grille style mismatch: FIX_AND_RESUBMIT (aesthetic)
- Missing controls sequence or points list: FIX_AND_RESUBMIT (coordination issue, not safety)
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Frequently asked questions
What are the most common deviations in Division 23 Heating, Ventilating, and Air Conditioning (HVAC) submittals?
The most common are product or manufacturer substitutions, performance specification gaps, and missing certification or compliance documentation. Deviation Check sorts every finding into one of six categories.
How are Division 23 deviations graded?
Each finding is graded Blocker (resolve before approval), Fix and Resubmit (correct and re-send before fabrication or install), or Note (acceptable with a comment).
View this page as Markdown for LLMs and note-taking.