CSI Division

Division 27: Communications submittal deviations

What changes between a Division 27 Communications spec section and the sub's submittal, why it matters, and how each deviation is graded.

By Deviation Check Editorial Team. Last reviewed June 1, 2026.

Short answer

Division 27 Communications 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 27 covers communications systems in commercial construction: structured cabling (copper and fiber), telecommunications rooms and infrastructure, wireless networks, distributed antenna systems (DAS), paging/intercom, and audio-visual systems. Common CSI sections submitted for review:

Common Division 27 CSI sections

Division 27 Communications spec sections frequently submitted for review:

Representative Division 27 CSI MasterFormat sections
Section	Title
`27 05 00`	Common Work Results for Communications
`27 05 26`	Grounding and Bonding for Communications Systems
`27 05 28`	Pathways for Communications Systems
`27 05 33`	Conduits and Backboxes for Communications Systems
`27 05 36`	Cable Trays for Communications Systems
`27 10 00`	Structured Cabling
`27 11 00`	Communications Equipment Room Fittings
`27 11 16`	Communications Cabinets, Racks, Frames, and Enclosures
`27 11 19`	Communications Termination Blocks and Patch Panels
`27 13 00`	Communications Backbone Cabling
`27 15 00`	Communications Horizontal Cabling
`27 15 01`	Communications Horizontal Cabling - Copper
`27 15 43`	Communications Faceplates and Connectors
`27 21 00`	Data Communications Network Equipment
`27 41 00`	Audio-Visual Systems
`27 42 00`	Electronic Digital Signage
`27 51 00`	Distributed Audio-Video Systems
`27 51 16`	Paging and Intercom Systems

The six deviation categories in Division 27 Communications

Every issue Deviation Check flags maps to one of six categories. Here is how each appears in Division 27 Communications 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.

Communications specs frequently name manufacturers with specific product lines for warranty and performance assurance. Mixed-manufacturer cabling systems void warranty coverage from most vendors. Look for:

Manufacturer or Product Substitution in Division 27 Communications submittals →

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 Div 27 submittals:

Performance Specification Gap in Division 27 Communications 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 Div 27 submittals:

Missing Certification or Compliance Documentation in Division 27 Communications submittals →

Aesthetic Deviation

Fix and Resubmit A visible attribute (color, finish, texture, profile) differs from the spec or the architect-approved sample.

Aesthetic Deviation in Division 27 Communications submittals →

Detail or Installation Mismatch

Fix and Resubmit The submitted detail, dimension, anchorage, or installation method differs from what the spec or drawings require.

Detail or Installation Mismatch in Division 27 Communications submittals →

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 27 specs:

Submittal Package Incompleteness in Division 27 Communications submittals →

How Division 27 deviations are graded

Each finding is graded Blocker, Fix and Resubmit, or Note. Division 27 escalation rules:

Cabling category below spec (Cat 6 where Cat 6A specified): BLOCKER (cannot support specified bandwidth)
Fiber type mismatch (OM3 where OM4 specified): BLOCKER (bandwidth/distance limitation)
Non-plenum cable in plenum space: BLOCKER (NEC Article 800, NFPA 90A, fire/smoke hazard)
Missing TIA-568 compliance test results for installed cabling: BLOCKER (no proof system meets performance)
Pathway fill exceeding TIA-569 40% limit: BLOCKER (code compliance, future capacity)
Missing UL 2043 listing for plenum components: BLOCKER (fire code)
Missing TIA-607 grounding/bonding documentation: BLOCKER if telecommunications grounding not addressed
Rack manufacturer substitution without equal performance data: FIX_AND_RESUBMIT
Faceplate color mismatch: FIX_AND_RESUBMIT (aesthetic, not safety)
Missing cable labeling plan per TIA-606: FIX_AND_RESUBMIT (administration requirement)
Wireless AP coverage below spec at cell edge: FIX_AND_RESUBMIT (performance gap, not life-safety)
Missing manufacturer warranty letter: FIX_AND_RESUBMIT (contractual, not code)
DAS coverage below -85 dBm threshold in required areas: FIX_AND_RESUBMIT unless emergency responder coverage - then BLOCKER per IFC Section 510

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Frequently asked questions

What are the most common deviations in Division 27 Communications 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 27 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.