Limited Specialty (D-Series) (C-61) · Lesson 2 of 6

D-28 Powered Doors and Automatic Gates: Leaf Count, Controls and Backup Power

"D-28 Powered Doors and Automatic Gates: Leaf Count, Controls and Backup Power" is lesson 2 of 6 in the Limited Specialty (D-Series) (C-61) Learning Hub. It opens with "What D-28 Covers and Which California Rules Apply" and works through 5 short steps, then a worked example you can check yourself against.

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Steps in this lesson

  1. What D-28 Covers and Which California Rules Apply
  2. The One-in-Eight Rule - CBC 11B-404.2.9
  3. Controls on Both Sides - CBC 11B-404.2.9 Item c
  4. Backup Power, Clear Width and Signs - CBC 11B-404.2.9 and 11B-404.3
  5. Automatic Vehicular Gates - CBC 3110

The worked example in the course applies this lesson to a realistic job in 5 steps, from "Opening force on the other leafs" through "Clear width and signs".

What you'll be able to do

  • Explain the main idea of "D-28 Powered Doors and Automatic Gates: Leaf Count, Controls and Backup Power" in plain language you can use on the exam.
  • Apply this step with confidence: "Controls on Both Sides - CBC 11B-404.2.9 Item c".
  • Apply this step with confidence: "Backup Power, Clear Width and Signs - CBC 11B-404.2.9 and 11B-404.3".
  • Apply this step with confidence: "Automatic Vehicular Gates - CBC 3110".
  • Test yourself on the worked example and the quick-check quiz inside the classroom.
D-28 POWERED DOORS: LEAF COUNT AND CONTROLSTen exterior leafs, occupant load 180, one entrance locationONE ENTRANCE: 10 EXTERIOR LEAFS2 powered8 manual: 8.5 lb maxCONTROL HEIGHTS ABOVE FLOORplate 2: 30-44 inplate 1: 7-8 inbar top35 in minbottom 5 in maxSIZE THE PACKAGE (CBC 11B-404)1) Powered: 10 / 8 = 1.25, round up = 2 leafs, nearest accessible route2) Other 8 leafs: 8.5 lb max (5 lb max if none are powered)3) Occupancy 180 is 150 or more: backup power, 100 cycles min4) Two push plates, both sides: centerlines 7-8 in and 30-44 in5) Bar bottom 4 in: length 35 - 4 = 31 in minimum6) Clear width 32 in, power on or offGates (3110): ASTM F2200, UL 325 openerRESULT: 2 powered leafs, 8.5 lb on the rest, 100-cycle backupSource: 2025 CBC 11B-404.2.9, 11B-404.3.1, 11B-404.3.6, 3110.2-3110.3; CSLB Get Licensed to Build, D-28.CC
The diagram for this lesson, exactly as it appears in the Learning Hub.

The first steps of this lesson

Step 1: What D-28 Covers and Which California Rules Apply

CSLB defines D-28 Doors, Gates and Activating Devices as installing, modifying or repairing all types of residential, commercial or industrial doors, including overhead and sliding assemblies, power-activated doors and gates, card-activated equipment and other access control devices, and any low-voltage electronic or manually operated door hardware (CSLB, Get Licensed to Build, D-28). Two California Building Code (CBC) rules give this class its hard numbers: CBC 11B-404 for powered and automatic doors and gates on accessible routes, and CBC 3110 for automatic vehicular gates. Egress hardware and panic devices are a separate topic (CBC Chapter 10 and the C-28 lessons); this lesson covers the powered side.

Step 2: The One-in-Eight Rule - CBC 11B-404.2.9

Opening force is 5 pounds maximum for interior hinged doors, sliding or folding doors, and exterior hinged doors (fire doors: the minimum the administrative authority allows, not over 15 pounds). The exception is what a D-28 installer uses daily: at a single location, when one of every eight exterior door leafs, or fraction of eight, is a powered door, the other exterior doors serving the same interior space may have an opening force of 8.5 pounds maximum. The powered leaf or leafs must be located closest to the accessible route, and powered doors must comply with 11B-404.3 as full-powered automatic doors (BHMA A156.10) or low-energy doors (BHMA A156.19). Count by rounding up: 10 leafs is 1.25 groups of eight, so 2 powered leafs.

The remaining 3 steps, the worked example and the quiz are in the course. This is a preview. The full lesson, with the step-by-step explanations, a worked example and a quick-check quiz, is inside the classroom.

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