Tag
nfpa-72
September 7, 2026 · 5 min read
The NFPA 72 Record of Completion Nobody Fills Out RightWhat actually goes in each NFPA 72 Record of Completion block, which signatures matter, and why one blank line can stall your certificate of occupancy.
August 27, 2026 · 5 min read
Fire Alarm Communicator Requirements After the POTS Line DiedPOTS is gone. Here's what AHJs actually want documented for cellular and dual path IP communicators, plus the panel compatibility trap that catches techs.
August 24, 2026 · 4 min read
Pull Station Mounting Height and Placement RulesPull station height, exit distance, and travel distance rules under NFPA 72 and ADA, plus the dual action question and why inspectors flag it so often.
August 20, 2026 · 6 min read
Smoke Detector Spacing: The Rules That Actually Get Enforced30 ft on center gets quoted a lot, but plan reviewers flag corridor width, beam pockets, and HVAC returns more. Here's what actually gets a comment letter.
July 28, 2026 · 6 min read
NFPA 72 Secondary Power: The 24-Hour Standby Rule ExplainedWhy NFPA 72 wants 24 hours of standby plus 5 minutes of alarm (15 for voice), how that feeds the battery calc, and when a generator fits instead.
July 13, 2026 · 6 min read
Building a Fire Alarm Device Matrix (With a Real Example)A walkthrough of a real device matrix: addresses, circuits, currents, and the annunciation and supervision columns a plan reviewer actually checks.
June 29, 2026 · 5 min read
Battery Calc Differences: Potter vs Fire-Lite vs Silent KnightHow Potter, Fire-Lite, and Silent Knight structure battery worksheets differently: where to find the numbers and how each handles the derating factor.
June 26, 2026 · 5 min read
Sizing a NAC Circuit: Current Limits and Voltage DropHow to add up horn/strobe current draw, apply NAC de-rating, and know when voltage drop forces a circuit split or booster.
June 25, 2026 · 5 min read
Duct Smoke Detector Requirements Without the GuessworkCFM thresholds, sampling tube sizing, remote station placement, and the IMC vs NFPA 72 overlap that catches fire alarm techs off guard.
June 24, 2026 · 5 min read
Class A vs Class B Fire Alarm Wiring: When and WhyUnderstand the survivability difference between Class A and Class B fire alarm wiring, where AHJs actually require Class A, and the real cost tradeoff.
June 23, 2026 · 5 min read
Fire Alarm Candela and Strobe Spacing, ExplainedHow to read the NFPA 72 candela tables for wall and ceiling strobes, pick the right cd rating for a real room, and avoid the sync gotcha.
June 21, 2026 · 8 min read
NFPA 72 Battery Calculation: A Step-by-Step Walkthrough for Working ContractorsWalk through the 24-hour standby and 5-minute alarm battery calc from NFPA 72 using real numbers from a Potter panel swap, including the 1.2x derating factor.
June 21, 2026 · 8 min read
Fire Alarm Voltage Drop Calculation: The Real Numbers (and Why Most Submittals Show Zero)How the fire alarm voltage drop calc actually works, why the panel maker's form almost always shows zero, and when you really need real wire-run numbers.
June 21, 2026 · 10 min read
What Goes in a Fire Alarm AHJ Submittal Package? (Based on 47 Real Approved Jobs)A practical checklist of every component in approved fire alarm permit packages, with notes on which AHJs want each one, from 47 real completed jobs.