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DALI vs DALI-2 — What Specifiers Need to Know in 2026

Backwards-compatibility myths, certification realities, and the spec wording that protects you when a contractor substitutes.

Tier 2 · Technical GuidanceUK · EU4.6 (47 ratings)654 learners
PR
Priya RamanathanMIET IEng

Senior Building Services Engineer — Hoare Lea

Section 1 of 4

First principles & design

Start from the physics — the why — then the design that flows from it. First principles is the design: the judgement AI can't recite.

The first-principles view is being prepared.

Every EngTree entry follows the same progression — first principles, design, interfaces, delivery. The contributor is finalising this section.

The design · EngTree Engineering

Theorist content is being prepared.

The author is finalising the theorist view — deep theory + first principles. You can switch to another lens above, or follow the channel to be notified when it ships.

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Section 2 of 4

Validation — codes & standards

The codes are the validation. Here's the chartered review, the standards cited, and the trust score that stands behind this design.

Knowledge Index™

72/100
Strongly verified
See breakdown
  • Author credentials (20%)12.0
  • Specialism match (10%)5.0
  • Validators × tier (25%)22.4
  • Standards currency (10%)0.0
  • Recency (10%)10.0
  • Field-application signal (10%)8.0
  • No dissent flag (5%)5.0
  • Jurisdictional precision (10%)10.0
  • · Author credential: MIET
  • · 2 validators
  • · Some cited standards may be superseded

EngTree's algorithmic trust score. Computed nightly from author credentials, validator chain, standards currency and recency. Higher is better.

Validators (2)

  • DM

    David MacLeod

    CEng MIET

    Verified against BS EN IEC 62386 series

    4 May 2026

  • SL

    Sarah Lemon

    MIET IEng

    Verified against BS EN 12464-1

    7 Apr 2026

Standards cited

  • BS EN IEC 62386 series
  • BS EN 12464-1

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Section 3 of 4

Interfaces & buildability

Where the validated design meets reality — coordination, technical interfaces, construction management, and the disciplines that hand off to each other. The bit textbooks skip.

The interfaces & buildability view is being prepared.

Every EngTree entry follows the same progression — first principles, design, interfaces, delivery. The contributor is finalising this section.

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Section 4 of 4

Delivery — on site

How it's actually built — by the trade professional who does it. Same topic, two credential chains: design ↔ delivery. EngTree Trade.

Every design has a delivery half. The chartered engineer sets the intent; the trade professional makes it real on site — and EngTree pairs them, so the same topic carries two credential chains.

Alongside is the paired Delivery entry from a trade-tier practitioner (Master Trade · EngTech · NICEIC · Gas Safe · NVQ L4).

Design → Delivery

The Delivery counterpart for this entry is in recruitment.

Every Design entry on EngTree is structurally paired with a Delivery entry from a trade-tier practitioner — Master Trade · EngTech · NICEIC · Gas Safe · NVQ Level 4. We're building this entry's Delivery half right now. If you're a senior site practitioner in this space and want to be the paired Delivery voice, get in touch.

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design_slug: dali-vs-dali-2-specifiers · no pair wired

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Ask & discuss· Roots · 12 comments

  • James O. (Graduate Geotechnical Engineer)

    3 weeks ago

    Used the α=0.45 figure on a job in Hackney last month — bentonite-installed piles, below water table. Load test came back within 4% of predicted. The negative skin friction reminder saved us; the made ground there is recent and consolidating measurably.

    ▲ 18Reply

  • Helena V., CEng MICE

    2 weeks ago

    The end-bearing reduction in fissured zones isn't widely appreciated. We had a project at Bank station where the textbook approach would've given us 30% more capacity than the actual fissured London clay supports. Recommend adding a sketch of typical fissure mapping.

    ▲ 11Reply

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Other perspectives on this topic

Multiple creators publish takes on the same sub-topic. Different experience, different jurisdictions, different angles. All chartered-validated, all ranked by Knowledge Index.

4 of 4 perspectives